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THE EFFECT OP A VARIABLE DRAPl lUBE FLOW AREA
ON 18 PERFORMlBOE OF A REACTION TURBINE
b7
BLISS DEAN RAY
A THESIS
submitted to
OREGOI SlAE OOLLEGE
in putlal tultlllment ot th-e requ1remente tor the
degree ot
MASBR OF SOIEWOE
June 19$7
Srr[ ffiHttlf f nralE
ffi frurld rr TmS fir6
Ioryw lltDilr0 I0 rfrq
Redacted for Privacy
rilE 0 r4mrro lmur rs ur-Ttqamp
Redacted for Privacy
trfrrryIlW ITITS ge lumrrE silrfrtHt
Redacted for Privacy
mftr o r8rne uf ffrTo Jc iprmJHa
Redacted for Privacy
rffilgtrIIY
or the many persona who have shown interest and
offered assistance in the progress or this investigation
certain ones merit special acknowledgment
In particular gratitude is expreased toward H G
Barnett Head or the Depaltment of Electrical Engineering
L N Stone Associate Professor of Electrical Engineering
and w H Paul Profeasoll of Automotive Engineering tor
their generous supply ot advice and equipment J R H Shoebull
maker Jr Assistant Professor of Civil Eng1neering for
his help and photographic work G w Holcomb Chairman or the Department of Oivil Engineering and w c Weatgarth
Assistant Professor of 01vil Engineering for thea
cooperation and assistance in obtaining material and
auppllea J Thomas B Hayes and Vtetor N Bredbullhoett ot the
oonaulting engineering firm or Cornell Howland Raybullbull and
Merryfield for their suggestions and encouragementJ H D
Pritchett tor the photoglaph1c duplication B K Scoggan
R D Smith D D Sweeney R M Elder R L Polv1 and
W H Knuth ror their b1releaa ettorts in the taking ot
data and Mra Jeanne Nepoundf for her patience in t he typing
ot the final draft ot the thesis
lb1a investigation could have been neither started
nor finished without the inapirat1on1 ideas and criticisms
of Fl-ed Merryfield Professor ot Sanitary Engineering to
whom a special debt is owed
Grant Robley Aas1stant Dean or t he School of Engibull
neering or Yal Un1ver ity ia the cause or it all
Arl1sa D Ray
bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull
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TABLE Qf CONTENTS
Chapter
I INTRODUCTION bull
A Purpose and Scope of Investigation bull bull bull bull l B Reaction Turbinea bull bull bull bull bull bull bull bull bull bull bull bull 2 C Draft Tubes bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 5
II DISCUSSION OF TURBI NE LOSSES bull bull bull bull bull bull bull bull 1
A General bull a Shock Loae ~ c Exit Loss 12
III PROPOSAL OF ALTERNATE METHOD OF CONTROL bull bull bull bullbull 14 A Type and Location of Control bull bull bull bull bull bull bull B Estimated Eftect on Actual Turbine bull bull bull bull ~ c Requirements tor Teet Verification bull bull bull bull 19
IV APPARATUS AND METHODS OP TESl bull bull bull bull bull bull bull bull bull 23
A Equipment bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 23 B InatlWilentation and Measuring Devicbullbull bull bull 26 c Operational Pz-ocedure bull bull bull bull bull bull bull bull bull bull 26 D Schedule ot Rune bull bull bull bull bull bull bull bull bull bull bull bull bull JS
v DATA bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 37
A Original Data bull bull bull bull bull bull bull bull bull bull B Calculated Data bull bull bull bull bull bull bull bull bull bull bull bull bull ~A
VI TEST RESULTS bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 44 A Presentation of Results bull bull bull bull bull bull bull bull bull 44B Discussion of aeaults $1
VII CONCLUSIONS bull middot 56bull bull bull bull bull bull bull bull bull bull bull BIBLIOGRAPY bull bull bull bull bull bull bull bull bull bull bull 51 APPENDICES bull bull bull bull bull bull bull bull bull bull bull 60
A lfotation bull bull bull bull 61 B Original Data bull bull bull bull bull bull bull bull bull bull bull bull bull bull 6)c Calculated Data bull bull bull bull bull bull bull bull bull bull bull 67
bull bull bull bull bull bull bull bull bull bull bull
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LIS~ OP_ __ ILLUSTRAfiOBS-middot
Fiere Page
1 13 $ Inch Reaction turbine bull bull bull bull bull bull bull bull bull bull 4
s bull bull bull bull bull bull bull bull bull bull bull bull
Plow Area bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 4S
2 Turbine Runner Vector D1agrama and Shook Loaa Diaptama bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 10
) Turbine PertoPmance CurYea bull bull bull bull bull bull bull bull bull bull 20
4 General View ot Teat Equipment bull bull bull bull bull bull bull 21
6 View ot Teat ut-bine bull bull bullmiddot bull bull bull bull bull bull bull bull bull 7 Teat Generator and Platform bull bull bull bull bull bull bull bull bull 27
8 Iutrument Board and Field Rheostat bull bull bull bull bull 27
9 Vlev ot Water lUteoatat bull bull bull bull bull bull bull bull bull bull 29
10 View or Water Rheostat bull 29
11 Vater Plow Diagram and Electrical Laout bull bull bull 30
12 Sketoh ot Draft ltlbe and Teat Inaerta bullbull bull bull 33
13 View ot Dratt Ube Inaer bull bull bull bull bull bull bull bull bull bull 34
14 Vlev ot Dr~t lube Iuert bull bull bull bull bull bull bull bull bull 34 lS Curves ot Generator Voltage Drop and Copper
Lose bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 40 16 euvtee of Oenerator Stray Power Lobullbull bull bull bull 41 17 Turbine Charae ter1at1ca with lOOC Dl-att lUbe
18 Turbine Characteristicbull With 7SC Draft tube Flow Area bull bull bull bull bull bull bull bull bull bull bullbull bull bullbull 46
19 Comparleon Between 7S~ and 100 Pratt Tubbull Flow Areas ot Power and Etf1c1ency at OVer Gate Condition bull bull bullbullbull bull bullbullbullbullbullbull 47
bull bull
~ Q ILLt1SlATlOIS (Continued)
F1pe
20 Comparison Between 15 and 100~ Draft Tube Flow Areas of PoweP and Ett1c1enoy at Halt Gate Condition bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 46
21 Oompu1aon Betwen S~ and 100~ Draft Tube Flow ANaa ot Po-r and Efflctency ab Ovbullbull Gate Condftimiddoton bull - bull bull bull bull - bull bull middot bull bull bull 49 Compar1aon ot Spec1tic Speeda tor 75~ middotand 10~ Draft Tube Flow Areae bull bull bull bull bull bull bull bull so
I
bull
filE EPPEOI OF A VARIABLE DRAFT TUBE FLOW AREA
ON THE PERFORMANltJE OF A REAOTIO TURBINE
Chapter l
IITRODUClIOH
A hrpose and Scope of Invst1pt1on
Present day control of reaction turbines is accombull
pl1ahed by the use of wicket gates immediately- preceding
the turbine runner These gates otter an interrelated conbull
- trol to the quantity and direction ot the water entering
t-he runner ie a change in the amount ot flow will rebull
middot ult in a change in direction This combined control leada
to loesee at all but the rated or design condition ot the
turbine (2$ Pbull )71)
This investigation dealt with an att mpt to better
turbine performance at all points of operation b y the
eatabliahment of separate controls over the rate of flow
and the d1J~ect1on ot the entering watebullbull
The only physical modification of the test tlutbine
was the insertion of flow restricting device in the dratt
tube
Ot primary interest were the trends in the change of
2
turbine performance with the amount ot draft tube tlow
area To this end complete turbine charaeteristiea were
not obtained tor 0ach device inserted in the draft tube
It was considered sutt1e1ent to obtain data tor the tull
speed range tor two representative gat openings one
greater and one less than the rated gate openingbull
Before proceeding with th report ot this 1nvest1gabull
t1on it 1a desirable to supply sa b ckground m terial
on reaction tw-blnes and their dratt tubes
B Raot1on 1rbinea
A hydraulic turbine is a device for converting the
energy in water to eohanical energy (6 Pbull 93lbull96S) furbull
b1nes may be loosely grouped into one of three elasse
impulsmiddote 1 reaot1on or propeller
An impulse turbine normally operates under a high head
and with a relatively sma~l amount ot watel in the converbull
sion or kinetic nergy to mechanical energy The propeller
turbine utilizes pressure energy to develop mechanical
energy while under a low head and p ss1ng a large amount of
waver
The reaction turbine lies somewhere between these two
extremes It changes both pressure and kinetic energy
while oper ting under a medium head with a moderate ount
opound water An example or a reaction turbine is pietur d in
Figure 1
lhe terms of high low small and so tomiddotrth are only
relative in sense A turbinebulls class1f1 eat1on is depenfent
upon its hoad rate of diacharge and speed of rot tion A
useful index tor turbine comparison (5 Pbull 825) is termed
specific speed and this ia a function of the rated ipeed
power output and head or the turbine The common range in
values ot speoitic speed ($ Pbull 826 ) tor each type ot tlirshy
bine is
Impulse J to SS tor one nozzle)Reaction bull 22 to 80 Propeller - 85 to 170
The development of t he reaction turbine began in the
early part or the nineteenth century (26 Pbull 1217bull1)6)
The trst efficient inward tlow turbine was de igned by
James B Francis an American in 1649bull For many years
turbine design was a matter of cutbullandbulltry in America an4
pure mathematical analysis 1n Europe It was not until the
two schools began exchanging ideas in the l$tter halt ot
the n1neteenth century that pronounced advancement was made
in the field
ObTioual7 the primary pux-pose ot any turbine inatallabull
t1on is t he production of power Added to this is the
restriction that the production or power must necessarily
be a controlled process An example of this is where the
turbine is direct-connected to an electric generator which
4
Figure 1 - 135 Inch Reaction Turbine
5
must operate at a constant speed or rotation even though _
the power demand ohangos In thiamp case the turbine nuet
be eap~able or producing a range of power output yet menshy
ta1n e eonetant speed
Speed regulation of the turbine iv accomplished by
means ot a governor (23 Pbull 24bull3-7) bull The contr-ol or regulashy
tion 1s indirect that i s the governor actually exereiaabull
control over the water in order to JJaintain e given speed
Co-ntrol over- the turbine end bence its speed and
power is the function ot a ring of movable wicket gates
located just upsttteam of the turbine runner These w1eket
gates 1n the process of opening and closing upon eeeh
0~1ar in a rotational manner actually control the amount
velocity and direction of tne water passing throu~~ them
C Draft Tubes
It has been found that the effeetive head on a reae
1l1on middotturbine is increased with the addi timiddoton of a draft tube
(3 Pbull 256bull264) Tne draft tube does thin by~
(1) Making a greater presaure d~op across the turbine
possible by the creation of a negative pressure at the
discharge or the runner and
2) DeoreaGing the k1net1e energy lost by increasing
the eross sectional area at exit
he draft tube permits the turbine runner to be
6
located above the tail race water surface without the
sacrifice of head However cavitation will cause pitting
of the turbine if the difference in elevation is too great
A common maximum elevation difference is 19 feet although
this figure is quite subject to modification between difshy
ferent installations (3 p middot 264-266)
There are many different types or draft tubes in use
today the choice or type being largely a matter or
economics (2$ p 368-370) A very common type particushy
larly among the smaller units is vertical with flaring
sides However the angle of flare is limited by the possishy
bility of separation of the flow from the sides In order
to achieve a certain discharge area the length of the tube
may be such as to require a great deal of excavation In
oases or this sort the cost of this excavation must be
balanced against a more elaborate design that does not
require as much excavation Other draft tubes in use
include the elbow hydracone and spreader types
Despite the differences found in construction and
design the draft tube must accomplish the desired objecshy
tives while offering a good hydraulic geometry to the flow
passing through it An inefficient draft tube defeats its
own purpose
Ohapter II
DISCUSSION ~ TURBINE LOSSES
A General
lhe head that 1a actually utilized by the turbine 1a
less than the effective bead as defined by equation ($) by
the amount that 1a lost due to mechanical and hydraulic
reasons
Mechanical loaaea are a function or the turbine 8p$ed
fhis ia not a lineaz- function but varies eomewhere between
N and N2 (3- Pbull 224)
Hydraulic losses encounteled in turbines ma- be subshy
divided aa to the location or occurrence (3 p 225-227) aa
fOllOW$S
(1) Penstock and scroll case
(2) Wicket gates
(3) Between wicket gates and turbine runner
(4) Runner passages
(5) Runner exit into draft tube
(6) Draft tube and
(7) At exit from the draft tube
The flow in the penstock scroll case wicket gates
runner passages and draft tube may be envisioned as
examples of flew in conventional pipes elbows and convergbull
1ng passages If this comparison may be made it could be
assumed that the losses encountered in these locations
would be proportional to vn ~ value ot N is normally2g
aesU111ed to be 2
he losses encountered between the wicket gates an4
the turbine runner and exit lossos are special cases which
will be discussed separately
B Shock toes_
The flow betwe n the wicket gat outlet and the runner
blade entrance is or particular 1nt rest because no direct
comparison vith common flow situations is obvious
Conaider the vector diagram (7 Pbull 7576) in Figure 2
The veetoo v1 is the absolute entering velocity of the
water and is fixed in magnitude and direction by the setbull
ting or the wicket gates The vector l11 1e the peripheztal
velocity of the runnel which tol any given turbine 1e
dependent only upon the turbine rotational speed The
combination of these two vectors ylelda the third vector
v1 which is the relative entering velocity ot the water
nere is only one setting ot the wicket gates for a
given turbine a peed that will produce an angle B1 which
coincides with the blade angle B1bull At other gate settings
the vector v1 will rotate and change in magnitude in such a
9
t ehion that B1 will beoome either greater or 1 sa than B1bull Th1 give rise to tbe phenomenon term d shock loasft
If B1 1a greater than B1 the relative ent ring veloebull
ityt v1 will have a compon~nt opposing the forward motion
of the runner The shock loss could be typified bullbull that
occasioned by direct impact or the water 0n the blade- If
E1 is lese than a] the vector l will overshoot the blade
and the flow will tend to eddy around the forward portion
or the blade tip
The shock loss can then be either due to impact or
eddying flow Since the area norm 1 to the radius at outlampt
of the w1eket gftee is essentially equ 1 to the area normnl
to the rad1u~ at the inlet to the turbine runner the combull
ponents ot vl and vl perpendicular to ul will b approxishy
mately equal This leads to the conclusion that xxbull ~epresenting the shock vector 1 parallel to Ulbull
For either the impact or eddy case the trigonometric
law of $1nee leads tot
XX
bull ul - sin (Bi-Al) vl eln Bi
It it 1a assumed that the energy lost in the shock 1a
the Telocity head ot the shock component XX then
10
VELOCITY VECTOR DIAGIWI
TYPES OF SHOCK LOSS
xbull X
IMPACT BDDJ
XX 1a Teloc1t7 caponent ot shock
Figure 2 - ~bine Runner Vector Diagram$ and Shock Loss Diagrams
11
2 shock loss (XX gt2g
C =sin (BimiddotAl)Let (1)sin Bi
(UlmiddotCV1)2Then shock loabull (2)- 2g
For a given gate opening C ia a constant ranging
from about 14 to 10 For a well designed wheel it is to middot
be expected that C would be approximately equal to U1V1
at rated conditions ie at point of maximum efficiency
This point will occur in the neighborhood of 3~ to 78
gate opening for moat turbines For overgate conditions
the angle A1 becomes larger so the value of C would
decrease For gate openings below rated conditions t he
angle A1 decreases and C would decrease One could expect
a fairly uniform decrease in t he value of C as the gate is
closed from t he overgate position
The velocity v1 is approximately constant for any
turbine speed since the area and rate of flow both decrease
fairly uniformly However for a given gate opening the
velocity V1 will decrease with increased turbine speed
From the foregoing comments and equation (2) the
following trends can be established
(1) For constant turbine speed the shook loss curve
will be close to parabolic in shape concave upward and
have its maximum near t he point of complete gate closure
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
Srr[ ffiHttlf f nralE
ffi frurld rr TmS fir6
Ioryw lltDilr0 I0 rfrq
Redacted for Privacy
rilE 0 r4mrro lmur rs ur-Ttqamp
Redacted for Privacy
trfrrryIlW ITITS ge lumrrE silrfrtHt
Redacted for Privacy
mftr o r8rne uf ffrTo Jc iprmJHa
Redacted for Privacy
rffilgtrIIY
or the many persona who have shown interest and
offered assistance in the progress or this investigation
certain ones merit special acknowledgment
In particular gratitude is expreased toward H G
Barnett Head or the Depaltment of Electrical Engineering
L N Stone Associate Professor of Electrical Engineering
and w H Paul Profeasoll of Automotive Engineering tor
their generous supply ot advice and equipment J R H Shoebull
maker Jr Assistant Professor of Civil Eng1neering for
his help and photographic work G w Holcomb Chairman or the Department of Oivil Engineering and w c Weatgarth
Assistant Professor of 01vil Engineering for thea
cooperation and assistance in obtaining material and
auppllea J Thomas B Hayes and Vtetor N Bredbullhoett ot the
oonaulting engineering firm or Cornell Howland Raybullbull and
Merryfield for their suggestions and encouragementJ H D
Pritchett tor the photoglaph1c duplication B K Scoggan
R D Smith D D Sweeney R M Elder R L Polv1 and
W H Knuth ror their b1releaa ettorts in the taking ot
data and Mra Jeanne Nepoundf for her patience in t he typing
ot the final draft ot the thesis
lb1a investigation could have been neither started
nor finished without the inapirat1on1 ideas and criticisms
of Fl-ed Merryfield Professor ot Sanitary Engineering to
whom a special debt is owed
Grant Robley Aas1stant Dean or t he School of Engibull
neering or Yal Un1ver ity ia the cause or it all
Arl1sa D Ray
bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull
bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull
bull bull bull bull
bull bull bull bull bull bull bull bull bull bull
bull bull bull bull bull bull bull bull bull bull bull bull bull
TABLE Qf CONTENTS
Chapter
I INTRODUCTION bull
A Purpose and Scope of Investigation bull bull bull bull l B Reaction Turbinea bull bull bull bull bull bull bull bull bull bull bull bull 2 C Draft Tubes bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 5
II DISCUSSION OF TURBI NE LOSSES bull bull bull bull bull bull bull bull 1
A General bull a Shock Loae ~ c Exit Loss 12
III PROPOSAL OF ALTERNATE METHOD OF CONTROL bull bull bull bullbull 14 A Type and Location of Control bull bull bull bull bull bull bull B Estimated Eftect on Actual Turbine bull bull bull bull ~ c Requirements tor Teet Verification bull bull bull bull 19
IV APPARATUS AND METHODS OP TESl bull bull bull bull bull bull bull bull bull 23
A Equipment bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 23 B InatlWilentation and Measuring Devicbullbull bull bull 26 c Operational Pz-ocedure bull bull bull bull bull bull bull bull bull bull 26 D Schedule ot Rune bull bull bull bull bull bull bull bull bull bull bull bull bull JS
v DATA bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 37
A Original Data bull bull bull bull bull bull bull bull bull bull B Calculated Data bull bull bull bull bull bull bull bull bull bull bull bull bull ~A
VI TEST RESULTS bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 44 A Presentation of Results bull bull bull bull bull bull bull bull bull 44B Discussion of aeaults $1
VII CONCLUSIONS bull middot 56bull bull bull bull bull bull bull bull bull bull bull BIBLIOGRAPY bull bull bull bull bull bull bull bull bull bull bull 51 APPENDICES bull bull bull bull bull bull bull bull bull bull bull 60
A lfotation bull bull bull bull 61 B Original Data bull bull bull bull bull bull bull bull bull bull bull bull bull bull 6)c Calculated Data bull bull bull bull bull bull bull bull bull bull bull 67
bull bull bull bull bull bull bull bull bull bull bull
bull bull
bull bull
LIS~ OP_ __ ILLUSTRAfiOBS-middot
Fiere Page
1 13 $ Inch Reaction turbine bull bull bull bull bull bull bull bull bull bull 4
s bull bull bull bull bull bull bull bull bull bull bull bull
Plow Area bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 4S
2 Turbine Runner Vector D1agrama and Shook Loaa Diaptama bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 10
) Turbine PertoPmance CurYea bull bull bull bull bull bull bull bull bull bull 20
4 General View ot Teat Equipment bull bull bull bull bull bull bull 21
6 View ot Teat ut-bine bull bull bullmiddot bull bull bull bull bull bull bull bull bull 7 Teat Generator and Platform bull bull bull bull bull bull bull bull bull 27
8 Iutrument Board and Field Rheostat bull bull bull bull bull 27
9 Vlev ot Water lUteoatat bull bull bull bull bull bull bull bull bull bull 29
10 View or Water Rheostat bull 29
11 Vater Plow Diagram and Electrical Laout bull bull bull 30
12 Sketoh ot Draft ltlbe and Teat Inaerta bullbull bull bull 33
13 View ot Dratt Ube Inaer bull bull bull bull bull bull bull bull bull bull 34
14 Vlev ot Dr~t lube Iuert bull bull bull bull bull bull bull bull bull 34 lS Curves ot Generator Voltage Drop and Copper
Lose bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 40 16 euvtee of Oenerator Stray Power Lobullbull bull bull bull 41 17 Turbine Charae ter1at1ca with lOOC Dl-att lUbe
18 Turbine Characteristicbull With 7SC Draft tube Flow Area bull bull bull bull bull bull bull bull bull bull bullbull bull bullbull 46
19 Comparleon Between 7S~ and 100 Pratt Tubbull Flow Areas ot Power and Etf1c1ency at OVer Gate Condition bull bull bullbullbull bull bullbullbullbullbullbull 47
bull bull
~ Q ILLt1SlATlOIS (Continued)
F1pe
20 Comparison Between 15 and 100~ Draft Tube Flow Areas of PoweP and Ett1c1enoy at Halt Gate Condition bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 46
21 Oompu1aon Betwen S~ and 100~ Draft Tube Flow ANaa ot Po-r and Efflctency ab Ovbullbull Gate Condftimiddoton bull - bull bull bull bull - bull bull middot bull bull bull 49 Compar1aon ot Spec1tic Speeda tor 75~ middotand 10~ Draft Tube Flow Areae bull bull bull bull bull bull bull bull so
I
bull
filE EPPEOI OF A VARIABLE DRAFT TUBE FLOW AREA
ON THE PERFORMANltJE OF A REAOTIO TURBINE
Chapter l
IITRODUClIOH
A hrpose and Scope of Invst1pt1on
Present day control of reaction turbines is accombull
pl1ahed by the use of wicket gates immediately- preceding
the turbine runner These gates otter an interrelated conbull
- trol to the quantity and direction ot the water entering
t-he runner ie a change in the amount ot flow will rebull
middot ult in a change in direction This combined control leada
to loesee at all but the rated or design condition ot the
turbine (2$ Pbull )71)
This investigation dealt with an att mpt to better
turbine performance at all points of operation b y the
eatabliahment of separate controls over the rate of flow
and the d1J~ect1on ot the entering watebullbull
The only physical modification of the test tlutbine
was the insertion of flow restricting device in the dratt
tube
Ot primary interest were the trends in the change of
2
turbine performance with the amount ot draft tube tlow
area To this end complete turbine charaeteristiea were
not obtained tor 0ach device inserted in the draft tube
It was considered sutt1e1ent to obtain data tor the tull
speed range tor two representative gat openings one
greater and one less than the rated gate openingbull
Before proceeding with th report ot this 1nvest1gabull
t1on it 1a desirable to supply sa b ckground m terial
on reaction tw-blnes and their dratt tubes
B Raot1on 1rbinea
A hydraulic turbine is a device for converting the
energy in water to eohanical energy (6 Pbull 93lbull96S) furbull
b1nes may be loosely grouped into one of three elasse
impulsmiddote 1 reaot1on or propeller
An impulse turbine normally operates under a high head
and with a relatively sma~l amount ot watel in the converbull
sion or kinetic nergy to mechanical energy The propeller
turbine utilizes pressure energy to develop mechanical
energy while under a low head and p ss1ng a large amount of
waver
The reaction turbine lies somewhere between these two
extremes It changes both pressure and kinetic energy
while oper ting under a medium head with a moderate ount
opound water An example or a reaction turbine is pietur d in
Figure 1
lhe terms of high low small and so tomiddotrth are only
relative in sense A turbinebulls class1f1 eat1on is depenfent
upon its hoad rate of diacharge and speed of rot tion A
useful index tor turbine comparison (5 Pbull 825) is termed
specific speed and this ia a function of the rated ipeed
power output and head or the turbine The common range in
values ot speoitic speed ($ Pbull 826 ) tor each type ot tlirshy
bine is
Impulse J to SS tor one nozzle)Reaction bull 22 to 80 Propeller - 85 to 170
The development of t he reaction turbine began in the
early part or the nineteenth century (26 Pbull 1217bull1)6)
The trst efficient inward tlow turbine was de igned by
James B Francis an American in 1649bull For many years
turbine design was a matter of cutbullandbulltry in America an4
pure mathematical analysis 1n Europe It was not until the
two schools began exchanging ideas in the l$tter halt ot
the n1neteenth century that pronounced advancement was made
in the field
ObTioual7 the primary pux-pose ot any turbine inatallabull
t1on is t he production of power Added to this is the
restriction that the production or power must necessarily
be a controlled process An example of this is where the
turbine is direct-connected to an electric generator which
4
Figure 1 - 135 Inch Reaction Turbine
5
must operate at a constant speed or rotation even though _
the power demand ohangos In thiamp case the turbine nuet
be eap~able or producing a range of power output yet menshy
ta1n e eonetant speed
Speed regulation of the turbine iv accomplished by
means ot a governor (23 Pbull 24bull3-7) bull The contr-ol or regulashy
tion 1s indirect that i s the governor actually exereiaabull
control over the water in order to JJaintain e given speed
Co-ntrol over- the turbine end bence its speed and
power is the function ot a ring of movable wicket gates
located just upsttteam of the turbine runner These w1eket
gates 1n the process of opening and closing upon eeeh
0~1ar in a rotational manner actually control the amount
velocity and direction of tne water passing throu~~ them
C Draft Tubes
It has been found that the effeetive head on a reae
1l1on middotturbine is increased with the addi timiddoton of a draft tube
(3 Pbull 256bull264) Tne draft tube does thin by~
(1) Making a greater presaure d~op across the turbine
possible by the creation of a negative pressure at the
discharge or the runner and
2) DeoreaGing the k1net1e energy lost by increasing
the eross sectional area at exit
he draft tube permits the turbine runner to be
6
located above the tail race water surface without the
sacrifice of head However cavitation will cause pitting
of the turbine if the difference in elevation is too great
A common maximum elevation difference is 19 feet although
this figure is quite subject to modification between difshy
ferent installations (3 p middot 264-266)
There are many different types or draft tubes in use
today the choice or type being largely a matter or
economics (2$ p 368-370) A very common type particushy
larly among the smaller units is vertical with flaring
sides However the angle of flare is limited by the possishy
bility of separation of the flow from the sides In order
to achieve a certain discharge area the length of the tube
may be such as to require a great deal of excavation In
oases or this sort the cost of this excavation must be
balanced against a more elaborate design that does not
require as much excavation Other draft tubes in use
include the elbow hydracone and spreader types
Despite the differences found in construction and
design the draft tube must accomplish the desired objecshy
tives while offering a good hydraulic geometry to the flow
passing through it An inefficient draft tube defeats its
own purpose
Ohapter II
DISCUSSION ~ TURBINE LOSSES
A General
lhe head that 1a actually utilized by the turbine 1a
less than the effective bead as defined by equation ($) by
the amount that 1a lost due to mechanical and hydraulic
reasons
Mechanical loaaea are a function or the turbine 8p$ed
fhis ia not a lineaz- function but varies eomewhere between
N and N2 (3- Pbull 224)
Hydraulic losses encounteled in turbines ma- be subshy
divided aa to the location or occurrence (3 p 225-227) aa
fOllOW$S
(1) Penstock and scroll case
(2) Wicket gates
(3) Between wicket gates and turbine runner
(4) Runner passages
(5) Runner exit into draft tube
(6) Draft tube and
(7) At exit from the draft tube
The flow in the penstock scroll case wicket gates
runner passages and draft tube may be envisioned as
examples of flew in conventional pipes elbows and convergbull
1ng passages If this comparison may be made it could be
assumed that the losses encountered in these locations
would be proportional to vn ~ value ot N is normally2g
aesU111ed to be 2
he losses encountered between the wicket gates an4
the turbine runner and exit lossos are special cases which
will be discussed separately
B Shock toes_
The flow betwe n the wicket gat outlet and the runner
blade entrance is or particular 1nt rest because no direct
comparison vith common flow situations is obvious
Conaider the vector diagram (7 Pbull 7576) in Figure 2
The veetoo v1 is the absolute entering velocity of the
water and is fixed in magnitude and direction by the setbull
ting or the wicket gates The vector l11 1e the peripheztal
velocity of the runnel which tol any given turbine 1e
dependent only upon the turbine rotational speed The
combination of these two vectors ylelda the third vector
v1 which is the relative entering velocity ot the water
nere is only one setting ot the wicket gates for a
given turbine a peed that will produce an angle B1 which
coincides with the blade angle B1bull At other gate settings
the vector v1 will rotate and change in magnitude in such a
9
t ehion that B1 will beoome either greater or 1 sa than B1bull Th1 give rise to tbe phenomenon term d shock loasft
If B1 1a greater than B1 the relative ent ring veloebull
ityt v1 will have a compon~nt opposing the forward motion
of the runner The shock loss could be typified bullbull that
occasioned by direct impact or the water 0n the blade- If
E1 is lese than a] the vector l will overshoot the blade
and the flow will tend to eddy around the forward portion
or the blade tip
The shock loss can then be either due to impact or
eddying flow Since the area norm 1 to the radius at outlampt
of the w1eket gftee is essentially equ 1 to the area normnl
to the rad1u~ at the inlet to the turbine runner the combull
ponents ot vl and vl perpendicular to ul will b approxishy
mately equal This leads to the conclusion that xxbull ~epresenting the shock vector 1 parallel to Ulbull
For either the impact or eddy case the trigonometric
law of $1nee leads tot
XX
bull ul - sin (Bi-Al) vl eln Bi
It it 1a assumed that the energy lost in the shock 1a
the Telocity head ot the shock component XX then
10
VELOCITY VECTOR DIAGIWI
TYPES OF SHOCK LOSS
xbull X
IMPACT BDDJ
XX 1a Teloc1t7 caponent ot shock
Figure 2 - ~bine Runner Vector Diagram$ and Shock Loss Diagrams
11
2 shock loss (XX gt2g
C =sin (BimiddotAl)Let (1)sin Bi
(UlmiddotCV1)2Then shock loabull (2)- 2g
For a given gate opening C ia a constant ranging
from about 14 to 10 For a well designed wheel it is to middot
be expected that C would be approximately equal to U1V1
at rated conditions ie at point of maximum efficiency
This point will occur in the neighborhood of 3~ to 78
gate opening for moat turbines For overgate conditions
the angle A1 becomes larger so the value of C would
decrease For gate openings below rated conditions t he
angle A1 decreases and C would decrease One could expect
a fairly uniform decrease in t he value of C as the gate is
closed from t he overgate position
The velocity v1 is approximately constant for any
turbine speed since the area and rate of flow both decrease
fairly uniformly However for a given gate opening the
velocity V1 will decrease with increased turbine speed
From the foregoing comments and equation (2) the
following trends can be established
(1) For constant turbine speed the shook loss curve
will be close to parabolic in shape concave upward and
have its maximum near t he point of complete gate closure
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
or the many persona who have shown interest and
offered assistance in the progress or this investigation
certain ones merit special acknowledgment
In particular gratitude is expreased toward H G
Barnett Head or the Depaltment of Electrical Engineering
L N Stone Associate Professor of Electrical Engineering
and w H Paul Profeasoll of Automotive Engineering tor
their generous supply ot advice and equipment J R H Shoebull
maker Jr Assistant Professor of Civil Eng1neering for
his help and photographic work G w Holcomb Chairman or the Department of Oivil Engineering and w c Weatgarth
Assistant Professor of 01vil Engineering for thea
cooperation and assistance in obtaining material and
auppllea J Thomas B Hayes and Vtetor N Bredbullhoett ot the
oonaulting engineering firm or Cornell Howland Raybullbull and
Merryfield for their suggestions and encouragementJ H D
Pritchett tor the photoglaph1c duplication B K Scoggan
R D Smith D D Sweeney R M Elder R L Polv1 and
W H Knuth ror their b1releaa ettorts in the taking ot
data and Mra Jeanne Nepoundf for her patience in t he typing
ot the final draft ot the thesis
lb1a investigation could have been neither started
nor finished without the inapirat1on1 ideas and criticisms
of Fl-ed Merryfield Professor ot Sanitary Engineering to
whom a special debt is owed
Grant Robley Aas1stant Dean or t he School of Engibull
neering or Yal Un1ver ity ia the cause or it all
Arl1sa D Ray
bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull
bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull
bull bull bull bull
bull bull bull bull bull bull bull bull bull bull
bull bull bull bull bull bull bull bull bull bull bull bull bull
TABLE Qf CONTENTS
Chapter
I INTRODUCTION bull
A Purpose and Scope of Investigation bull bull bull bull l B Reaction Turbinea bull bull bull bull bull bull bull bull bull bull bull bull 2 C Draft Tubes bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 5
II DISCUSSION OF TURBI NE LOSSES bull bull bull bull bull bull bull bull 1
A General bull a Shock Loae ~ c Exit Loss 12
III PROPOSAL OF ALTERNATE METHOD OF CONTROL bull bull bull bullbull 14 A Type and Location of Control bull bull bull bull bull bull bull B Estimated Eftect on Actual Turbine bull bull bull bull ~ c Requirements tor Teet Verification bull bull bull bull 19
IV APPARATUS AND METHODS OP TESl bull bull bull bull bull bull bull bull bull 23
A Equipment bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 23 B InatlWilentation and Measuring Devicbullbull bull bull 26 c Operational Pz-ocedure bull bull bull bull bull bull bull bull bull bull 26 D Schedule ot Rune bull bull bull bull bull bull bull bull bull bull bull bull bull JS
v DATA bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 37
A Original Data bull bull bull bull bull bull bull bull bull bull B Calculated Data bull bull bull bull bull bull bull bull bull bull bull bull bull ~A
VI TEST RESULTS bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 44 A Presentation of Results bull bull bull bull bull bull bull bull bull 44B Discussion of aeaults $1
VII CONCLUSIONS bull middot 56bull bull bull bull bull bull bull bull bull bull bull BIBLIOGRAPY bull bull bull bull bull bull bull bull bull bull bull 51 APPENDICES bull bull bull bull bull bull bull bull bull bull bull 60
A lfotation bull bull bull bull 61 B Original Data bull bull bull bull bull bull bull bull bull bull bull bull bull bull 6)c Calculated Data bull bull bull bull bull bull bull bull bull bull bull 67
bull bull bull bull bull bull bull bull bull bull bull
bull bull
bull bull
LIS~ OP_ __ ILLUSTRAfiOBS-middot
Fiere Page
1 13 $ Inch Reaction turbine bull bull bull bull bull bull bull bull bull bull 4
s bull bull bull bull bull bull bull bull bull bull bull bull
Plow Area bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 4S
2 Turbine Runner Vector D1agrama and Shook Loaa Diaptama bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 10
) Turbine PertoPmance CurYea bull bull bull bull bull bull bull bull bull bull 20
4 General View ot Teat Equipment bull bull bull bull bull bull bull 21
6 View ot Teat ut-bine bull bull bullmiddot bull bull bull bull bull bull bull bull bull 7 Teat Generator and Platform bull bull bull bull bull bull bull bull bull 27
8 Iutrument Board and Field Rheostat bull bull bull bull bull 27
9 Vlev ot Water lUteoatat bull bull bull bull bull bull bull bull bull bull 29
10 View or Water Rheostat bull 29
11 Vater Plow Diagram and Electrical Laout bull bull bull 30
12 Sketoh ot Draft ltlbe and Teat Inaerta bullbull bull bull 33
13 View ot Dratt Ube Inaer bull bull bull bull bull bull bull bull bull bull 34
14 Vlev ot Dr~t lube Iuert bull bull bull bull bull bull bull bull bull 34 lS Curves ot Generator Voltage Drop and Copper
Lose bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 40 16 euvtee of Oenerator Stray Power Lobullbull bull bull bull 41 17 Turbine Charae ter1at1ca with lOOC Dl-att lUbe
18 Turbine Characteristicbull With 7SC Draft tube Flow Area bull bull bull bull bull bull bull bull bull bull bullbull bull bullbull 46
19 Comparleon Between 7S~ and 100 Pratt Tubbull Flow Areas ot Power and Etf1c1ency at OVer Gate Condition bull bull bullbullbull bull bullbullbullbullbullbull 47
bull bull
~ Q ILLt1SlATlOIS (Continued)
F1pe
20 Comparison Between 15 and 100~ Draft Tube Flow Areas of PoweP and Ett1c1enoy at Halt Gate Condition bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 46
21 Oompu1aon Betwen S~ and 100~ Draft Tube Flow ANaa ot Po-r and Efflctency ab Ovbullbull Gate Condftimiddoton bull - bull bull bull bull - bull bull middot bull bull bull 49 Compar1aon ot Spec1tic Speeda tor 75~ middotand 10~ Draft Tube Flow Areae bull bull bull bull bull bull bull bull so
I
bull
filE EPPEOI OF A VARIABLE DRAFT TUBE FLOW AREA
ON THE PERFORMANltJE OF A REAOTIO TURBINE
Chapter l
IITRODUClIOH
A hrpose and Scope of Invst1pt1on
Present day control of reaction turbines is accombull
pl1ahed by the use of wicket gates immediately- preceding
the turbine runner These gates otter an interrelated conbull
- trol to the quantity and direction ot the water entering
t-he runner ie a change in the amount ot flow will rebull
middot ult in a change in direction This combined control leada
to loesee at all but the rated or design condition ot the
turbine (2$ Pbull )71)
This investigation dealt with an att mpt to better
turbine performance at all points of operation b y the
eatabliahment of separate controls over the rate of flow
and the d1J~ect1on ot the entering watebullbull
The only physical modification of the test tlutbine
was the insertion of flow restricting device in the dratt
tube
Ot primary interest were the trends in the change of
2
turbine performance with the amount ot draft tube tlow
area To this end complete turbine charaeteristiea were
not obtained tor 0ach device inserted in the draft tube
It was considered sutt1e1ent to obtain data tor the tull
speed range tor two representative gat openings one
greater and one less than the rated gate openingbull
Before proceeding with th report ot this 1nvest1gabull
t1on it 1a desirable to supply sa b ckground m terial
on reaction tw-blnes and their dratt tubes
B Raot1on 1rbinea
A hydraulic turbine is a device for converting the
energy in water to eohanical energy (6 Pbull 93lbull96S) furbull
b1nes may be loosely grouped into one of three elasse
impulsmiddote 1 reaot1on or propeller
An impulse turbine normally operates under a high head
and with a relatively sma~l amount ot watel in the converbull
sion or kinetic nergy to mechanical energy The propeller
turbine utilizes pressure energy to develop mechanical
energy while under a low head and p ss1ng a large amount of
waver
The reaction turbine lies somewhere between these two
extremes It changes both pressure and kinetic energy
while oper ting under a medium head with a moderate ount
opound water An example or a reaction turbine is pietur d in
Figure 1
lhe terms of high low small and so tomiddotrth are only
relative in sense A turbinebulls class1f1 eat1on is depenfent
upon its hoad rate of diacharge and speed of rot tion A
useful index tor turbine comparison (5 Pbull 825) is termed
specific speed and this ia a function of the rated ipeed
power output and head or the turbine The common range in
values ot speoitic speed ($ Pbull 826 ) tor each type ot tlirshy
bine is
Impulse J to SS tor one nozzle)Reaction bull 22 to 80 Propeller - 85 to 170
The development of t he reaction turbine began in the
early part or the nineteenth century (26 Pbull 1217bull1)6)
The trst efficient inward tlow turbine was de igned by
James B Francis an American in 1649bull For many years
turbine design was a matter of cutbullandbulltry in America an4
pure mathematical analysis 1n Europe It was not until the
two schools began exchanging ideas in the l$tter halt ot
the n1neteenth century that pronounced advancement was made
in the field
ObTioual7 the primary pux-pose ot any turbine inatallabull
t1on is t he production of power Added to this is the
restriction that the production or power must necessarily
be a controlled process An example of this is where the
turbine is direct-connected to an electric generator which
4
Figure 1 - 135 Inch Reaction Turbine
5
must operate at a constant speed or rotation even though _
the power demand ohangos In thiamp case the turbine nuet
be eap~able or producing a range of power output yet menshy
ta1n e eonetant speed
Speed regulation of the turbine iv accomplished by
means ot a governor (23 Pbull 24bull3-7) bull The contr-ol or regulashy
tion 1s indirect that i s the governor actually exereiaabull
control over the water in order to JJaintain e given speed
Co-ntrol over- the turbine end bence its speed and
power is the function ot a ring of movable wicket gates
located just upsttteam of the turbine runner These w1eket
gates 1n the process of opening and closing upon eeeh
0~1ar in a rotational manner actually control the amount
velocity and direction of tne water passing throu~~ them
C Draft Tubes
It has been found that the effeetive head on a reae
1l1on middotturbine is increased with the addi timiddoton of a draft tube
(3 Pbull 256bull264) Tne draft tube does thin by~
(1) Making a greater presaure d~op across the turbine
possible by the creation of a negative pressure at the
discharge or the runner and
2) DeoreaGing the k1net1e energy lost by increasing
the eross sectional area at exit
he draft tube permits the turbine runner to be
6
located above the tail race water surface without the
sacrifice of head However cavitation will cause pitting
of the turbine if the difference in elevation is too great
A common maximum elevation difference is 19 feet although
this figure is quite subject to modification between difshy
ferent installations (3 p middot 264-266)
There are many different types or draft tubes in use
today the choice or type being largely a matter or
economics (2$ p 368-370) A very common type particushy
larly among the smaller units is vertical with flaring
sides However the angle of flare is limited by the possishy
bility of separation of the flow from the sides In order
to achieve a certain discharge area the length of the tube
may be such as to require a great deal of excavation In
oases or this sort the cost of this excavation must be
balanced against a more elaborate design that does not
require as much excavation Other draft tubes in use
include the elbow hydracone and spreader types
Despite the differences found in construction and
design the draft tube must accomplish the desired objecshy
tives while offering a good hydraulic geometry to the flow
passing through it An inefficient draft tube defeats its
own purpose
Ohapter II
DISCUSSION ~ TURBINE LOSSES
A General
lhe head that 1a actually utilized by the turbine 1a
less than the effective bead as defined by equation ($) by
the amount that 1a lost due to mechanical and hydraulic
reasons
Mechanical loaaea are a function or the turbine 8p$ed
fhis ia not a lineaz- function but varies eomewhere between
N and N2 (3- Pbull 224)
Hydraulic losses encounteled in turbines ma- be subshy
divided aa to the location or occurrence (3 p 225-227) aa
fOllOW$S
(1) Penstock and scroll case
(2) Wicket gates
(3) Between wicket gates and turbine runner
(4) Runner passages
(5) Runner exit into draft tube
(6) Draft tube and
(7) At exit from the draft tube
The flow in the penstock scroll case wicket gates
runner passages and draft tube may be envisioned as
examples of flew in conventional pipes elbows and convergbull
1ng passages If this comparison may be made it could be
assumed that the losses encountered in these locations
would be proportional to vn ~ value ot N is normally2g
aesU111ed to be 2
he losses encountered between the wicket gates an4
the turbine runner and exit lossos are special cases which
will be discussed separately
B Shock toes_
The flow betwe n the wicket gat outlet and the runner
blade entrance is or particular 1nt rest because no direct
comparison vith common flow situations is obvious
Conaider the vector diagram (7 Pbull 7576) in Figure 2
The veetoo v1 is the absolute entering velocity of the
water and is fixed in magnitude and direction by the setbull
ting or the wicket gates The vector l11 1e the peripheztal
velocity of the runnel which tol any given turbine 1e
dependent only upon the turbine rotational speed The
combination of these two vectors ylelda the third vector
v1 which is the relative entering velocity ot the water
nere is only one setting ot the wicket gates for a
given turbine a peed that will produce an angle B1 which
coincides with the blade angle B1bull At other gate settings
the vector v1 will rotate and change in magnitude in such a
9
t ehion that B1 will beoome either greater or 1 sa than B1bull Th1 give rise to tbe phenomenon term d shock loasft
If B1 1a greater than B1 the relative ent ring veloebull
ityt v1 will have a compon~nt opposing the forward motion
of the runner The shock loss could be typified bullbull that
occasioned by direct impact or the water 0n the blade- If
E1 is lese than a] the vector l will overshoot the blade
and the flow will tend to eddy around the forward portion
or the blade tip
The shock loss can then be either due to impact or
eddying flow Since the area norm 1 to the radius at outlampt
of the w1eket gftee is essentially equ 1 to the area normnl
to the rad1u~ at the inlet to the turbine runner the combull
ponents ot vl and vl perpendicular to ul will b approxishy
mately equal This leads to the conclusion that xxbull ~epresenting the shock vector 1 parallel to Ulbull
For either the impact or eddy case the trigonometric
law of $1nee leads tot
XX
bull ul - sin (Bi-Al) vl eln Bi
It it 1a assumed that the energy lost in the shock 1a
the Telocity head ot the shock component XX then
10
VELOCITY VECTOR DIAGIWI
TYPES OF SHOCK LOSS
xbull X
IMPACT BDDJ
XX 1a Teloc1t7 caponent ot shock
Figure 2 - ~bine Runner Vector Diagram$ and Shock Loss Diagrams
11
2 shock loss (XX gt2g
C =sin (BimiddotAl)Let (1)sin Bi
(UlmiddotCV1)2Then shock loabull (2)- 2g
For a given gate opening C ia a constant ranging
from about 14 to 10 For a well designed wheel it is to middot
be expected that C would be approximately equal to U1V1
at rated conditions ie at point of maximum efficiency
This point will occur in the neighborhood of 3~ to 78
gate opening for moat turbines For overgate conditions
the angle A1 becomes larger so the value of C would
decrease For gate openings below rated conditions t he
angle A1 decreases and C would decrease One could expect
a fairly uniform decrease in t he value of C as the gate is
closed from t he overgate position
The velocity v1 is approximately constant for any
turbine speed since the area and rate of flow both decrease
fairly uniformly However for a given gate opening the
velocity V1 will decrease with increased turbine speed
From the foregoing comments and equation (2) the
following trends can be established
(1) For constant turbine speed the shook loss curve
will be close to parabolic in shape concave upward and
have its maximum near t he point of complete gate closure
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
nor finished without the inapirat1on1 ideas and criticisms
of Fl-ed Merryfield Professor ot Sanitary Engineering to
whom a special debt is owed
Grant Robley Aas1stant Dean or t he School of Engibull
neering or Yal Un1ver ity ia the cause or it all
Arl1sa D Ray
bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull
bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull
bull bull bull bull
bull bull bull bull bull bull bull bull bull bull
bull bull bull bull bull bull bull bull bull bull bull bull bull
TABLE Qf CONTENTS
Chapter
I INTRODUCTION bull
A Purpose and Scope of Investigation bull bull bull bull l B Reaction Turbinea bull bull bull bull bull bull bull bull bull bull bull bull 2 C Draft Tubes bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 5
II DISCUSSION OF TURBI NE LOSSES bull bull bull bull bull bull bull bull 1
A General bull a Shock Loae ~ c Exit Loss 12
III PROPOSAL OF ALTERNATE METHOD OF CONTROL bull bull bull bullbull 14 A Type and Location of Control bull bull bull bull bull bull bull B Estimated Eftect on Actual Turbine bull bull bull bull ~ c Requirements tor Teet Verification bull bull bull bull 19
IV APPARATUS AND METHODS OP TESl bull bull bull bull bull bull bull bull bull 23
A Equipment bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 23 B InatlWilentation and Measuring Devicbullbull bull bull 26 c Operational Pz-ocedure bull bull bull bull bull bull bull bull bull bull 26 D Schedule ot Rune bull bull bull bull bull bull bull bull bull bull bull bull bull JS
v DATA bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 37
A Original Data bull bull bull bull bull bull bull bull bull bull B Calculated Data bull bull bull bull bull bull bull bull bull bull bull bull bull ~A
VI TEST RESULTS bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 44 A Presentation of Results bull bull bull bull bull bull bull bull bull 44B Discussion of aeaults $1
VII CONCLUSIONS bull middot 56bull bull bull bull bull bull bull bull bull bull bull BIBLIOGRAPY bull bull bull bull bull bull bull bull bull bull bull 51 APPENDICES bull bull bull bull bull bull bull bull bull bull bull 60
A lfotation bull bull bull bull 61 B Original Data bull bull bull bull bull bull bull bull bull bull bull bull bull bull 6)c Calculated Data bull bull bull bull bull bull bull bull bull bull bull 67
bull bull bull bull bull bull bull bull bull bull bull
bull bull
bull bull
LIS~ OP_ __ ILLUSTRAfiOBS-middot
Fiere Page
1 13 $ Inch Reaction turbine bull bull bull bull bull bull bull bull bull bull 4
s bull bull bull bull bull bull bull bull bull bull bull bull
Plow Area bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 4S
2 Turbine Runner Vector D1agrama and Shook Loaa Diaptama bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 10
) Turbine PertoPmance CurYea bull bull bull bull bull bull bull bull bull bull 20
4 General View ot Teat Equipment bull bull bull bull bull bull bull 21
6 View ot Teat ut-bine bull bull bullmiddot bull bull bull bull bull bull bull bull bull 7 Teat Generator and Platform bull bull bull bull bull bull bull bull bull 27
8 Iutrument Board and Field Rheostat bull bull bull bull bull 27
9 Vlev ot Water lUteoatat bull bull bull bull bull bull bull bull bull bull 29
10 View or Water Rheostat bull 29
11 Vater Plow Diagram and Electrical Laout bull bull bull 30
12 Sketoh ot Draft ltlbe and Teat Inaerta bullbull bull bull 33
13 View ot Dratt Ube Inaer bull bull bull bull bull bull bull bull bull bull 34
14 Vlev ot Dr~t lube Iuert bull bull bull bull bull bull bull bull bull 34 lS Curves ot Generator Voltage Drop and Copper
Lose bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 40 16 euvtee of Oenerator Stray Power Lobullbull bull bull bull 41 17 Turbine Charae ter1at1ca with lOOC Dl-att lUbe
18 Turbine Characteristicbull With 7SC Draft tube Flow Area bull bull bull bull bull bull bull bull bull bull bullbull bull bullbull 46
19 Comparleon Between 7S~ and 100 Pratt Tubbull Flow Areas ot Power and Etf1c1ency at OVer Gate Condition bull bull bullbullbull bull bullbullbullbullbullbull 47
bull bull
~ Q ILLt1SlATlOIS (Continued)
F1pe
20 Comparison Between 15 and 100~ Draft Tube Flow Areas of PoweP and Ett1c1enoy at Halt Gate Condition bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 46
21 Oompu1aon Betwen S~ and 100~ Draft Tube Flow ANaa ot Po-r and Efflctency ab Ovbullbull Gate Condftimiddoton bull - bull bull bull bull - bull bull middot bull bull bull 49 Compar1aon ot Spec1tic Speeda tor 75~ middotand 10~ Draft Tube Flow Areae bull bull bull bull bull bull bull bull so
I
bull
filE EPPEOI OF A VARIABLE DRAFT TUBE FLOW AREA
ON THE PERFORMANltJE OF A REAOTIO TURBINE
Chapter l
IITRODUClIOH
A hrpose and Scope of Invst1pt1on
Present day control of reaction turbines is accombull
pl1ahed by the use of wicket gates immediately- preceding
the turbine runner These gates otter an interrelated conbull
- trol to the quantity and direction ot the water entering
t-he runner ie a change in the amount ot flow will rebull
middot ult in a change in direction This combined control leada
to loesee at all but the rated or design condition ot the
turbine (2$ Pbull )71)
This investigation dealt with an att mpt to better
turbine performance at all points of operation b y the
eatabliahment of separate controls over the rate of flow
and the d1J~ect1on ot the entering watebullbull
The only physical modification of the test tlutbine
was the insertion of flow restricting device in the dratt
tube
Ot primary interest were the trends in the change of
2
turbine performance with the amount ot draft tube tlow
area To this end complete turbine charaeteristiea were
not obtained tor 0ach device inserted in the draft tube
It was considered sutt1e1ent to obtain data tor the tull
speed range tor two representative gat openings one
greater and one less than the rated gate openingbull
Before proceeding with th report ot this 1nvest1gabull
t1on it 1a desirable to supply sa b ckground m terial
on reaction tw-blnes and their dratt tubes
B Raot1on 1rbinea
A hydraulic turbine is a device for converting the
energy in water to eohanical energy (6 Pbull 93lbull96S) furbull
b1nes may be loosely grouped into one of three elasse
impulsmiddote 1 reaot1on or propeller
An impulse turbine normally operates under a high head
and with a relatively sma~l amount ot watel in the converbull
sion or kinetic nergy to mechanical energy The propeller
turbine utilizes pressure energy to develop mechanical
energy while under a low head and p ss1ng a large amount of
waver
The reaction turbine lies somewhere between these two
extremes It changes both pressure and kinetic energy
while oper ting under a medium head with a moderate ount
opound water An example or a reaction turbine is pietur d in
Figure 1
lhe terms of high low small and so tomiddotrth are only
relative in sense A turbinebulls class1f1 eat1on is depenfent
upon its hoad rate of diacharge and speed of rot tion A
useful index tor turbine comparison (5 Pbull 825) is termed
specific speed and this ia a function of the rated ipeed
power output and head or the turbine The common range in
values ot speoitic speed ($ Pbull 826 ) tor each type ot tlirshy
bine is
Impulse J to SS tor one nozzle)Reaction bull 22 to 80 Propeller - 85 to 170
The development of t he reaction turbine began in the
early part or the nineteenth century (26 Pbull 1217bull1)6)
The trst efficient inward tlow turbine was de igned by
James B Francis an American in 1649bull For many years
turbine design was a matter of cutbullandbulltry in America an4
pure mathematical analysis 1n Europe It was not until the
two schools began exchanging ideas in the l$tter halt ot
the n1neteenth century that pronounced advancement was made
in the field
ObTioual7 the primary pux-pose ot any turbine inatallabull
t1on is t he production of power Added to this is the
restriction that the production or power must necessarily
be a controlled process An example of this is where the
turbine is direct-connected to an electric generator which
4
Figure 1 - 135 Inch Reaction Turbine
5
must operate at a constant speed or rotation even though _
the power demand ohangos In thiamp case the turbine nuet
be eap~able or producing a range of power output yet menshy
ta1n e eonetant speed
Speed regulation of the turbine iv accomplished by
means ot a governor (23 Pbull 24bull3-7) bull The contr-ol or regulashy
tion 1s indirect that i s the governor actually exereiaabull
control over the water in order to JJaintain e given speed
Co-ntrol over- the turbine end bence its speed and
power is the function ot a ring of movable wicket gates
located just upsttteam of the turbine runner These w1eket
gates 1n the process of opening and closing upon eeeh
0~1ar in a rotational manner actually control the amount
velocity and direction of tne water passing throu~~ them
C Draft Tubes
It has been found that the effeetive head on a reae
1l1on middotturbine is increased with the addi timiddoton of a draft tube
(3 Pbull 256bull264) Tne draft tube does thin by~
(1) Making a greater presaure d~op across the turbine
possible by the creation of a negative pressure at the
discharge or the runner and
2) DeoreaGing the k1net1e energy lost by increasing
the eross sectional area at exit
he draft tube permits the turbine runner to be
6
located above the tail race water surface without the
sacrifice of head However cavitation will cause pitting
of the turbine if the difference in elevation is too great
A common maximum elevation difference is 19 feet although
this figure is quite subject to modification between difshy
ferent installations (3 p middot 264-266)
There are many different types or draft tubes in use
today the choice or type being largely a matter or
economics (2$ p 368-370) A very common type particushy
larly among the smaller units is vertical with flaring
sides However the angle of flare is limited by the possishy
bility of separation of the flow from the sides In order
to achieve a certain discharge area the length of the tube
may be such as to require a great deal of excavation In
oases or this sort the cost of this excavation must be
balanced against a more elaborate design that does not
require as much excavation Other draft tubes in use
include the elbow hydracone and spreader types
Despite the differences found in construction and
design the draft tube must accomplish the desired objecshy
tives while offering a good hydraulic geometry to the flow
passing through it An inefficient draft tube defeats its
own purpose
Ohapter II
DISCUSSION ~ TURBINE LOSSES
A General
lhe head that 1a actually utilized by the turbine 1a
less than the effective bead as defined by equation ($) by
the amount that 1a lost due to mechanical and hydraulic
reasons
Mechanical loaaea are a function or the turbine 8p$ed
fhis ia not a lineaz- function but varies eomewhere between
N and N2 (3- Pbull 224)
Hydraulic losses encounteled in turbines ma- be subshy
divided aa to the location or occurrence (3 p 225-227) aa
fOllOW$S
(1) Penstock and scroll case
(2) Wicket gates
(3) Between wicket gates and turbine runner
(4) Runner passages
(5) Runner exit into draft tube
(6) Draft tube and
(7) At exit from the draft tube
The flow in the penstock scroll case wicket gates
runner passages and draft tube may be envisioned as
examples of flew in conventional pipes elbows and convergbull
1ng passages If this comparison may be made it could be
assumed that the losses encountered in these locations
would be proportional to vn ~ value ot N is normally2g
aesU111ed to be 2
he losses encountered between the wicket gates an4
the turbine runner and exit lossos are special cases which
will be discussed separately
B Shock toes_
The flow betwe n the wicket gat outlet and the runner
blade entrance is or particular 1nt rest because no direct
comparison vith common flow situations is obvious
Conaider the vector diagram (7 Pbull 7576) in Figure 2
The veetoo v1 is the absolute entering velocity of the
water and is fixed in magnitude and direction by the setbull
ting or the wicket gates The vector l11 1e the peripheztal
velocity of the runnel which tol any given turbine 1e
dependent only upon the turbine rotational speed The
combination of these two vectors ylelda the third vector
v1 which is the relative entering velocity ot the water
nere is only one setting ot the wicket gates for a
given turbine a peed that will produce an angle B1 which
coincides with the blade angle B1bull At other gate settings
the vector v1 will rotate and change in magnitude in such a
9
t ehion that B1 will beoome either greater or 1 sa than B1bull Th1 give rise to tbe phenomenon term d shock loasft
If B1 1a greater than B1 the relative ent ring veloebull
ityt v1 will have a compon~nt opposing the forward motion
of the runner The shock loss could be typified bullbull that
occasioned by direct impact or the water 0n the blade- If
E1 is lese than a] the vector l will overshoot the blade
and the flow will tend to eddy around the forward portion
or the blade tip
The shock loss can then be either due to impact or
eddying flow Since the area norm 1 to the radius at outlampt
of the w1eket gftee is essentially equ 1 to the area normnl
to the rad1u~ at the inlet to the turbine runner the combull
ponents ot vl and vl perpendicular to ul will b approxishy
mately equal This leads to the conclusion that xxbull ~epresenting the shock vector 1 parallel to Ulbull
For either the impact or eddy case the trigonometric
law of $1nee leads tot
XX
bull ul - sin (Bi-Al) vl eln Bi
It it 1a assumed that the energy lost in the shock 1a
the Telocity head ot the shock component XX then
10
VELOCITY VECTOR DIAGIWI
TYPES OF SHOCK LOSS
xbull X
IMPACT BDDJ
XX 1a Teloc1t7 caponent ot shock
Figure 2 - ~bine Runner Vector Diagram$ and Shock Loss Diagrams
11
2 shock loss (XX gt2g
C =sin (BimiddotAl)Let (1)sin Bi
(UlmiddotCV1)2Then shock loabull (2)- 2g
For a given gate opening C ia a constant ranging
from about 14 to 10 For a well designed wheel it is to middot
be expected that C would be approximately equal to U1V1
at rated conditions ie at point of maximum efficiency
This point will occur in the neighborhood of 3~ to 78
gate opening for moat turbines For overgate conditions
the angle A1 becomes larger so the value of C would
decrease For gate openings below rated conditions t he
angle A1 decreases and C would decrease One could expect
a fairly uniform decrease in t he value of C as the gate is
closed from t he overgate position
The velocity v1 is approximately constant for any
turbine speed since the area and rate of flow both decrease
fairly uniformly However for a given gate opening the
velocity V1 will decrease with increased turbine speed
From the foregoing comments and equation (2) the
following trends can be established
(1) For constant turbine speed the shook loss curve
will be close to parabolic in shape concave upward and
have its maximum near t he point of complete gate closure
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull
bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull
bull bull bull bull
bull bull bull bull bull bull bull bull bull bull
bull bull bull bull bull bull bull bull bull bull bull bull bull
TABLE Qf CONTENTS
Chapter
I INTRODUCTION bull
A Purpose and Scope of Investigation bull bull bull bull l B Reaction Turbinea bull bull bull bull bull bull bull bull bull bull bull bull 2 C Draft Tubes bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 5
II DISCUSSION OF TURBI NE LOSSES bull bull bull bull bull bull bull bull 1
A General bull a Shock Loae ~ c Exit Loss 12
III PROPOSAL OF ALTERNATE METHOD OF CONTROL bull bull bull bullbull 14 A Type and Location of Control bull bull bull bull bull bull bull B Estimated Eftect on Actual Turbine bull bull bull bull ~ c Requirements tor Teet Verification bull bull bull bull 19
IV APPARATUS AND METHODS OP TESl bull bull bull bull bull bull bull bull bull 23
A Equipment bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 23 B InatlWilentation and Measuring Devicbullbull bull bull 26 c Operational Pz-ocedure bull bull bull bull bull bull bull bull bull bull 26 D Schedule ot Rune bull bull bull bull bull bull bull bull bull bull bull bull bull JS
v DATA bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 37
A Original Data bull bull bull bull bull bull bull bull bull bull B Calculated Data bull bull bull bull bull bull bull bull bull bull bull bull bull ~A
VI TEST RESULTS bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 44 A Presentation of Results bull bull bull bull bull bull bull bull bull 44B Discussion of aeaults $1
VII CONCLUSIONS bull middot 56bull bull bull bull bull bull bull bull bull bull bull BIBLIOGRAPY bull bull bull bull bull bull bull bull bull bull bull 51 APPENDICES bull bull bull bull bull bull bull bull bull bull bull 60
A lfotation bull bull bull bull 61 B Original Data bull bull bull bull bull bull bull bull bull bull bull bull bull bull 6)c Calculated Data bull bull bull bull bull bull bull bull bull bull bull 67
bull bull bull bull bull bull bull bull bull bull bull
bull bull
bull bull
LIS~ OP_ __ ILLUSTRAfiOBS-middot
Fiere Page
1 13 $ Inch Reaction turbine bull bull bull bull bull bull bull bull bull bull 4
s bull bull bull bull bull bull bull bull bull bull bull bull
Plow Area bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 4S
2 Turbine Runner Vector D1agrama and Shook Loaa Diaptama bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 10
) Turbine PertoPmance CurYea bull bull bull bull bull bull bull bull bull bull 20
4 General View ot Teat Equipment bull bull bull bull bull bull bull 21
6 View ot Teat ut-bine bull bull bullmiddot bull bull bull bull bull bull bull bull bull 7 Teat Generator and Platform bull bull bull bull bull bull bull bull bull 27
8 Iutrument Board and Field Rheostat bull bull bull bull bull 27
9 Vlev ot Water lUteoatat bull bull bull bull bull bull bull bull bull bull 29
10 View or Water Rheostat bull 29
11 Vater Plow Diagram and Electrical Laout bull bull bull 30
12 Sketoh ot Draft ltlbe and Teat Inaerta bullbull bull bull 33
13 View ot Dratt Ube Inaer bull bull bull bull bull bull bull bull bull bull 34
14 Vlev ot Dr~t lube Iuert bull bull bull bull bull bull bull bull bull 34 lS Curves ot Generator Voltage Drop and Copper
Lose bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 40 16 euvtee of Oenerator Stray Power Lobullbull bull bull bull 41 17 Turbine Charae ter1at1ca with lOOC Dl-att lUbe
18 Turbine Characteristicbull With 7SC Draft tube Flow Area bull bull bull bull bull bull bull bull bull bull bullbull bull bullbull 46
19 Comparleon Between 7S~ and 100 Pratt Tubbull Flow Areas ot Power and Etf1c1ency at OVer Gate Condition bull bull bullbullbull bull bullbullbullbullbullbull 47
bull bull
~ Q ILLt1SlATlOIS (Continued)
F1pe
20 Comparison Between 15 and 100~ Draft Tube Flow Areas of PoweP and Ett1c1enoy at Halt Gate Condition bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 46
21 Oompu1aon Betwen S~ and 100~ Draft Tube Flow ANaa ot Po-r and Efflctency ab Ovbullbull Gate Condftimiddoton bull - bull bull bull bull - bull bull middot bull bull bull 49 Compar1aon ot Spec1tic Speeda tor 75~ middotand 10~ Draft Tube Flow Areae bull bull bull bull bull bull bull bull so
I
bull
filE EPPEOI OF A VARIABLE DRAFT TUBE FLOW AREA
ON THE PERFORMANltJE OF A REAOTIO TURBINE
Chapter l
IITRODUClIOH
A hrpose and Scope of Invst1pt1on
Present day control of reaction turbines is accombull
pl1ahed by the use of wicket gates immediately- preceding
the turbine runner These gates otter an interrelated conbull
- trol to the quantity and direction ot the water entering
t-he runner ie a change in the amount ot flow will rebull
middot ult in a change in direction This combined control leada
to loesee at all but the rated or design condition ot the
turbine (2$ Pbull )71)
This investigation dealt with an att mpt to better
turbine performance at all points of operation b y the
eatabliahment of separate controls over the rate of flow
and the d1J~ect1on ot the entering watebullbull
The only physical modification of the test tlutbine
was the insertion of flow restricting device in the dratt
tube
Ot primary interest were the trends in the change of
2
turbine performance with the amount ot draft tube tlow
area To this end complete turbine charaeteristiea were
not obtained tor 0ach device inserted in the draft tube
It was considered sutt1e1ent to obtain data tor the tull
speed range tor two representative gat openings one
greater and one less than the rated gate openingbull
Before proceeding with th report ot this 1nvest1gabull
t1on it 1a desirable to supply sa b ckground m terial
on reaction tw-blnes and their dratt tubes
B Raot1on 1rbinea
A hydraulic turbine is a device for converting the
energy in water to eohanical energy (6 Pbull 93lbull96S) furbull
b1nes may be loosely grouped into one of three elasse
impulsmiddote 1 reaot1on or propeller
An impulse turbine normally operates under a high head
and with a relatively sma~l amount ot watel in the converbull
sion or kinetic nergy to mechanical energy The propeller
turbine utilizes pressure energy to develop mechanical
energy while under a low head and p ss1ng a large amount of
waver
The reaction turbine lies somewhere between these two
extremes It changes both pressure and kinetic energy
while oper ting under a medium head with a moderate ount
opound water An example or a reaction turbine is pietur d in
Figure 1
lhe terms of high low small and so tomiddotrth are only
relative in sense A turbinebulls class1f1 eat1on is depenfent
upon its hoad rate of diacharge and speed of rot tion A
useful index tor turbine comparison (5 Pbull 825) is termed
specific speed and this ia a function of the rated ipeed
power output and head or the turbine The common range in
values ot speoitic speed ($ Pbull 826 ) tor each type ot tlirshy
bine is
Impulse J to SS tor one nozzle)Reaction bull 22 to 80 Propeller - 85 to 170
The development of t he reaction turbine began in the
early part or the nineteenth century (26 Pbull 1217bull1)6)
The trst efficient inward tlow turbine was de igned by
James B Francis an American in 1649bull For many years
turbine design was a matter of cutbullandbulltry in America an4
pure mathematical analysis 1n Europe It was not until the
two schools began exchanging ideas in the l$tter halt ot
the n1neteenth century that pronounced advancement was made
in the field
ObTioual7 the primary pux-pose ot any turbine inatallabull
t1on is t he production of power Added to this is the
restriction that the production or power must necessarily
be a controlled process An example of this is where the
turbine is direct-connected to an electric generator which
4
Figure 1 - 135 Inch Reaction Turbine
5
must operate at a constant speed or rotation even though _
the power demand ohangos In thiamp case the turbine nuet
be eap~able or producing a range of power output yet menshy
ta1n e eonetant speed
Speed regulation of the turbine iv accomplished by
means ot a governor (23 Pbull 24bull3-7) bull The contr-ol or regulashy
tion 1s indirect that i s the governor actually exereiaabull
control over the water in order to JJaintain e given speed
Co-ntrol over- the turbine end bence its speed and
power is the function ot a ring of movable wicket gates
located just upsttteam of the turbine runner These w1eket
gates 1n the process of opening and closing upon eeeh
0~1ar in a rotational manner actually control the amount
velocity and direction of tne water passing throu~~ them
C Draft Tubes
It has been found that the effeetive head on a reae
1l1on middotturbine is increased with the addi timiddoton of a draft tube
(3 Pbull 256bull264) Tne draft tube does thin by~
(1) Making a greater presaure d~op across the turbine
possible by the creation of a negative pressure at the
discharge or the runner and
2) DeoreaGing the k1net1e energy lost by increasing
the eross sectional area at exit
he draft tube permits the turbine runner to be
6
located above the tail race water surface without the
sacrifice of head However cavitation will cause pitting
of the turbine if the difference in elevation is too great
A common maximum elevation difference is 19 feet although
this figure is quite subject to modification between difshy
ferent installations (3 p middot 264-266)
There are many different types or draft tubes in use
today the choice or type being largely a matter or
economics (2$ p 368-370) A very common type particushy
larly among the smaller units is vertical with flaring
sides However the angle of flare is limited by the possishy
bility of separation of the flow from the sides In order
to achieve a certain discharge area the length of the tube
may be such as to require a great deal of excavation In
oases or this sort the cost of this excavation must be
balanced against a more elaborate design that does not
require as much excavation Other draft tubes in use
include the elbow hydracone and spreader types
Despite the differences found in construction and
design the draft tube must accomplish the desired objecshy
tives while offering a good hydraulic geometry to the flow
passing through it An inefficient draft tube defeats its
own purpose
Ohapter II
DISCUSSION ~ TURBINE LOSSES
A General
lhe head that 1a actually utilized by the turbine 1a
less than the effective bead as defined by equation ($) by
the amount that 1a lost due to mechanical and hydraulic
reasons
Mechanical loaaea are a function or the turbine 8p$ed
fhis ia not a lineaz- function but varies eomewhere between
N and N2 (3- Pbull 224)
Hydraulic losses encounteled in turbines ma- be subshy
divided aa to the location or occurrence (3 p 225-227) aa
fOllOW$S
(1) Penstock and scroll case
(2) Wicket gates
(3) Between wicket gates and turbine runner
(4) Runner passages
(5) Runner exit into draft tube
(6) Draft tube and
(7) At exit from the draft tube
The flow in the penstock scroll case wicket gates
runner passages and draft tube may be envisioned as
examples of flew in conventional pipes elbows and convergbull
1ng passages If this comparison may be made it could be
assumed that the losses encountered in these locations
would be proportional to vn ~ value ot N is normally2g
aesU111ed to be 2
he losses encountered between the wicket gates an4
the turbine runner and exit lossos are special cases which
will be discussed separately
B Shock toes_
The flow betwe n the wicket gat outlet and the runner
blade entrance is or particular 1nt rest because no direct
comparison vith common flow situations is obvious
Conaider the vector diagram (7 Pbull 7576) in Figure 2
The veetoo v1 is the absolute entering velocity of the
water and is fixed in magnitude and direction by the setbull
ting or the wicket gates The vector l11 1e the peripheztal
velocity of the runnel which tol any given turbine 1e
dependent only upon the turbine rotational speed The
combination of these two vectors ylelda the third vector
v1 which is the relative entering velocity ot the water
nere is only one setting ot the wicket gates for a
given turbine a peed that will produce an angle B1 which
coincides with the blade angle B1bull At other gate settings
the vector v1 will rotate and change in magnitude in such a
9
t ehion that B1 will beoome either greater or 1 sa than B1bull Th1 give rise to tbe phenomenon term d shock loasft
If B1 1a greater than B1 the relative ent ring veloebull
ityt v1 will have a compon~nt opposing the forward motion
of the runner The shock loss could be typified bullbull that
occasioned by direct impact or the water 0n the blade- If
E1 is lese than a] the vector l will overshoot the blade
and the flow will tend to eddy around the forward portion
or the blade tip
The shock loss can then be either due to impact or
eddying flow Since the area norm 1 to the radius at outlampt
of the w1eket gftee is essentially equ 1 to the area normnl
to the rad1u~ at the inlet to the turbine runner the combull
ponents ot vl and vl perpendicular to ul will b approxishy
mately equal This leads to the conclusion that xxbull ~epresenting the shock vector 1 parallel to Ulbull
For either the impact or eddy case the trigonometric
law of $1nee leads tot
XX
bull ul - sin (Bi-Al) vl eln Bi
It it 1a assumed that the energy lost in the shock 1a
the Telocity head ot the shock component XX then
10
VELOCITY VECTOR DIAGIWI
TYPES OF SHOCK LOSS
xbull X
IMPACT BDDJ
XX 1a Teloc1t7 caponent ot shock
Figure 2 - ~bine Runner Vector Diagram$ and Shock Loss Diagrams
11
2 shock loss (XX gt2g
C =sin (BimiddotAl)Let (1)sin Bi
(UlmiddotCV1)2Then shock loabull (2)- 2g
For a given gate opening C ia a constant ranging
from about 14 to 10 For a well designed wheel it is to middot
be expected that C would be approximately equal to U1V1
at rated conditions ie at point of maximum efficiency
This point will occur in the neighborhood of 3~ to 78
gate opening for moat turbines For overgate conditions
the angle A1 becomes larger so the value of C would
decrease For gate openings below rated conditions t he
angle A1 decreases and C would decrease One could expect
a fairly uniform decrease in t he value of C as the gate is
closed from t he overgate position
The velocity v1 is approximately constant for any
turbine speed since the area and rate of flow both decrease
fairly uniformly However for a given gate opening the
velocity V1 will decrease with increased turbine speed
From the foregoing comments and equation (2) the
following trends can be established
(1) For constant turbine speed the shook loss curve
will be close to parabolic in shape concave upward and
have its maximum near t he point of complete gate closure
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
bull bull bull bull bull bull bull bull bull bull bull
bull bull
bull bull
LIS~ OP_ __ ILLUSTRAfiOBS-middot
Fiere Page
1 13 $ Inch Reaction turbine bull bull bull bull bull bull bull bull bull bull 4
s bull bull bull bull bull bull bull bull bull bull bull bull
Plow Area bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 4S
2 Turbine Runner Vector D1agrama and Shook Loaa Diaptama bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 10
) Turbine PertoPmance CurYea bull bull bull bull bull bull bull bull bull bull 20
4 General View ot Teat Equipment bull bull bull bull bull bull bull 21
6 View ot Teat ut-bine bull bull bullmiddot bull bull bull bull bull bull bull bull bull 7 Teat Generator and Platform bull bull bull bull bull bull bull bull bull 27
8 Iutrument Board and Field Rheostat bull bull bull bull bull 27
9 Vlev ot Water lUteoatat bull bull bull bull bull bull bull bull bull bull 29
10 View or Water Rheostat bull 29
11 Vater Plow Diagram and Electrical Laout bull bull bull 30
12 Sketoh ot Draft ltlbe and Teat Inaerta bullbull bull bull 33
13 View ot Dratt Ube Inaer bull bull bull bull bull bull bull bull bull bull 34
14 Vlev ot Dr~t lube Iuert bull bull bull bull bull bull bull bull bull 34 lS Curves ot Generator Voltage Drop and Copper
Lose bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 40 16 euvtee of Oenerator Stray Power Lobullbull bull bull bull 41 17 Turbine Charae ter1at1ca with lOOC Dl-att lUbe
18 Turbine Characteristicbull With 7SC Draft tube Flow Area bull bull bull bull bull bull bull bull bull bull bullbull bull bullbull 46
19 Comparleon Between 7S~ and 100 Pratt Tubbull Flow Areas ot Power and Etf1c1ency at OVer Gate Condition bull bull bullbullbull bull bullbullbullbullbullbull 47
bull bull
~ Q ILLt1SlATlOIS (Continued)
F1pe
20 Comparison Between 15 and 100~ Draft Tube Flow Areas of PoweP and Ett1c1enoy at Halt Gate Condition bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 46
21 Oompu1aon Betwen S~ and 100~ Draft Tube Flow ANaa ot Po-r and Efflctency ab Ovbullbull Gate Condftimiddoton bull - bull bull bull bull - bull bull middot bull bull bull 49 Compar1aon ot Spec1tic Speeda tor 75~ middotand 10~ Draft Tube Flow Areae bull bull bull bull bull bull bull bull so
I
bull
filE EPPEOI OF A VARIABLE DRAFT TUBE FLOW AREA
ON THE PERFORMANltJE OF A REAOTIO TURBINE
Chapter l
IITRODUClIOH
A hrpose and Scope of Invst1pt1on
Present day control of reaction turbines is accombull
pl1ahed by the use of wicket gates immediately- preceding
the turbine runner These gates otter an interrelated conbull
- trol to the quantity and direction ot the water entering
t-he runner ie a change in the amount ot flow will rebull
middot ult in a change in direction This combined control leada
to loesee at all but the rated or design condition ot the
turbine (2$ Pbull )71)
This investigation dealt with an att mpt to better
turbine performance at all points of operation b y the
eatabliahment of separate controls over the rate of flow
and the d1J~ect1on ot the entering watebullbull
The only physical modification of the test tlutbine
was the insertion of flow restricting device in the dratt
tube
Ot primary interest were the trends in the change of
2
turbine performance with the amount ot draft tube tlow
area To this end complete turbine charaeteristiea were
not obtained tor 0ach device inserted in the draft tube
It was considered sutt1e1ent to obtain data tor the tull
speed range tor two representative gat openings one
greater and one less than the rated gate openingbull
Before proceeding with th report ot this 1nvest1gabull
t1on it 1a desirable to supply sa b ckground m terial
on reaction tw-blnes and their dratt tubes
B Raot1on 1rbinea
A hydraulic turbine is a device for converting the
energy in water to eohanical energy (6 Pbull 93lbull96S) furbull
b1nes may be loosely grouped into one of three elasse
impulsmiddote 1 reaot1on or propeller
An impulse turbine normally operates under a high head
and with a relatively sma~l amount ot watel in the converbull
sion or kinetic nergy to mechanical energy The propeller
turbine utilizes pressure energy to develop mechanical
energy while under a low head and p ss1ng a large amount of
waver
The reaction turbine lies somewhere between these two
extremes It changes both pressure and kinetic energy
while oper ting under a medium head with a moderate ount
opound water An example or a reaction turbine is pietur d in
Figure 1
lhe terms of high low small and so tomiddotrth are only
relative in sense A turbinebulls class1f1 eat1on is depenfent
upon its hoad rate of diacharge and speed of rot tion A
useful index tor turbine comparison (5 Pbull 825) is termed
specific speed and this ia a function of the rated ipeed
power output and head or the turbine The common range in
values ot speoitic speed ($ Pbull 826 ) tor each type ot tlirshy
bine is
Impulse J to SS tor one nozzle)Reaction bull 22 to 80 Propeller - 85 to 170
The development of t he reaction turbine began in the
early part or the nineteenth century (26 Pbull 1217bull1)6)
The trst efficient inward tlow turbine was de igned by
James B Francis an American in 1649bull For many years
turbine design was a matter of cutbullandbulltry in America an4
pure mathematical analysis 1n Europe It was not until the
two schools began exchanging ideas in the l$tter halt ot
the n1neteenth century that pronounced advancement was made
in the field
ObTioual7 the primary pux-pose ot any turbine inatallabull
t1on is t he production of power Added to this is the
restriction that the production or power must necessarily
be a controlled process An example of this is where the
turbine is direct-connected to an electric generator which
4
Figure 1 - 135 Inch Reaction Turbine
5
must operate at a constant speed or rotation even though _
the power demand ohangos In thiamp case the turbine nuet
be eap~able or producing a range of power output yet menshy
ta1n e eonetant speed
Speed regulation of the turbine iv accomplished by
means ot a governor (23 Pbull 24bull3-7) bull The contr-ol or regulashy
tion 1s indirect that i s the governor actually exereiaabull
control over the water in order to JJaintain e given speed
Co-ntrol over- the turbine end bence its speed and
power is the function ot a ring of movable wicket gates
located just upsttteam of the turbine runner These w1eket
gates 1n the process of opening and closing upon eeeh
0~1ar in a rotational manner actually control the amount
velocity and direction of tne water passing throu~~ them
C Draft Tubes
It has been found that the effeetive head on a reae
1l1on middotturbine is increased with the addi timiddoton of a draft tube
(3 Pbull 256bull264) Tne draft tube does thin by~
(1) Making a greater presaure d~op across the turbine
possible by the creation of a negative pressure at the
discharge or the runner and
2) DeoreaGing the k1net1e energy lost by increasing
the eross sectional area at exit
he draft tube permits the turbine runner to be
6
located above the tail race water surface without the
sacrifice of head However cavitation will cause pitting
of the turbine if the difference in elevation is too great
A common maximum elevation difference is 19 feet although
this figure is quite subject to modification between difshy
ferent installations (3 p middot 264-266)
There are many different types or draft tubes in use
today the choice or type being largely a matter or
economics (2$ p 368-370) A very common type particushy
larly among the smaller units is vertical with flaring
sides However the angle of flare is limited by the possishy
bility of separation of the flow from the sides In order
to achieve a certain discharge area the length of the tube
may be such as to require a great deal of excavation In
oases or this sort the cost of this excavation must be
balanced against a more elaborate design that does not
require as much excavation Other draft tubes in use
include the elbow hydracone and spreader types
Despite the differences found in construction and
design the draft tube must accomplish the desired objecshy
tives while offering a good hydraulic geometry to the flow
passing through it An inefficient draft tube defeats its
own purpose
Ohapter II
DISCUSSION ~ TURBINE LOSSES
A General
lhe head that 1a actually utilized by the turbine 1a
less than the effective bead as defined by equation ($) by
the amount that 1a lost due to mechanical and hydraulic
reasons
Mechanical loaaea are a function or the turbine 8p$ed
fhis ia not a lineaz- function but varies eomewhere between
N and N2 (3- Pbull 224)
Hydraulic losses encounteled in turbines ma- be subshy
divided aa to the location or occurrence (3 p 225-227) aa
fOllOW$S
(1) Penstock and scroll case
(2) Wicket gates
(3) Between wicket gates and turbine runner
(4) Runner passages
(5) Runner exit into draft tube
(6) Draft tube and
(7) At exit from the draft tube
The flow in the penstock scroll case wicket gates
runner passages and draft tube may be envisioned as
examples of flew in conventional pipes elbows and convergbull
1ng passages If this comparison may be made it could be
assumed that the losses encountered in these locations
would be proportional to vn ~ value ot N is normally2g
aesU111ed to be 2
he losses encountered between the wicket gates an4
the turbine runner and exit lossos are special cases which
will be discussed separately
B Shock toes_
The flow betwe n the wicket gat outlet and the runner
blade entrance is or particular 1nt rest because no direct
comparison vith common flow situations is obvious
Conaider the vector diagram (7 Pbull 7576) in Figure 2
The veetoo v1 is the absolute entering velocity of the
water and is fixed in magnitude and direction by the setbull
ting or the wicket gates The vector l11 1e the peripheztal
velocity of the runnel which tol any given turbine 1e
dependent only upon the turbine rotational speed The
combination of these two vectors ylelda the third vector
v1 which is the relative entering velocity ot the water
nere is only one setting ot the wicket gates for a
given turbine a peed that will produce an angle B1 which
coincides with the blade angle B1bull At other gate settings
the vector v1 will rotate and change in magnitude in such a
9
t ehion that B1 will beoome either greater or 1 sa than B1bull Th1 give rise to tbe phenomenon term d shock loasft
If B1 1a greater than B1 the relative ent ring veloebull
ityt v1 will have a compon~nt opposing the forward motion
of the runner The shock loss could be typified bullbull that
occasioned by direct impact or the water 0n the blade- If
E1 is lese than a] the vector l will overshoot the blade
and the flow will tend to eddy around the forward portion
or the blade tip
The shock loss can then be either due to impact or
eddying flow Since the area norm 1 to the radius at outlampt
of the w1eket gftee is essentially equ 1 to the area normnl
to the rad1u~ at the inlet to the turbine runner the combull
ponents ot vl and vl perpendicular to ul will b approxishy
mately equal This leads to the conclusion that xxbull ~epresenting the shock vector 1 parallel to Ulbull
For either the impact or eddy case the trigonometric
law of $1nee leads tot
XX
bull ul - sin (Bi-Al) vl eln Bi
It it 1a assumed that the energy lost in the shock 1a
the Telocity head ot the shock component XX then
10
VELOCITY VECTOR DIAGIWI
TYPES OF SHOCK LOSS
xbull X
IMPACT BDDJ
XX 1a Teloc1t7 caponent ot shock
Figure 2 - ~bine Runner Vector Diagram$ and Shock Loss Diagrams
11
2 shock loss (XX gt2g
C =sin (BimiddotAl)Let (1)sin Bi
(UlmiddotCV1)2Then shock loabull (2)- 2g
For a given gate opening C ia a constant ranging
from about 14 to 10 For a well designed wheel it is to middot
be expected that C would be approximately equal to U1V1
at rated conditions ie at point of maximum efficiency
This point will occur in the neighborhood of 3~ to 78
gate opening for moat turbines For overgate conditions
the angle A1 becomes larger so the value of C would
decrease For gate openings below rated conditions t he
angle A1 decreases and C would decrease One could expect
a fairly uniform decrease in t he value of C as the gate is
closed from t he overgate position
The velocity v1 is approximately constant for any
turbine speed since the area and rate of flow both decrease
fairly uniformly However for a given gate opening the
velocity V1 will decrease with increased turbine speed
From the foregoing comments and equation (2) the
following trends can be established
(1) For constant turbine speed the shook loss curve
will be close to parabolic in shape concave upward and
have its maximum near t he point of complete gate closure
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
bull bull
~ Q ILLt1SlATlOIS (Continued)
F1pe
20 Comparison Between 15 and 100~ Draft Tube Flow Areas of PoweP and Ett1c1enoy at Halt Gate Condition bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 46
21 Oompu1aon Betwen S~ and 100~ Draft Tube Flow ANaa ot Po-r and Efflctency ab Ovbullbull Gate Condftimiddoton bull - bull bull bull bull - bull bull middot bull bull bull 49 Compar1aon ot Spec1tic Speeda tor 75~ middotand 10~ Draft Tube Flow Areae bull bull bull bull bull bull bull bull so
I
bull
filE EPPEOI OF A VARIABLE DRAFT TUBE FLOW AREA
ON THE PERFORMANltJE OF A REAOTIO TURBINE
Chapter l
IITRODUClIOH
A hrpose and Scope of Invst1pt1on
Present day control of reaction turbines is accombull
pl1ahed by the use of wicket gates immediately- preceding
the turbine runner These gates otter an interrelated conbull
- trol to the quantity and direction ot the water entering
t-he runner ie a change in the amount ot flow will rebull
middot ult in a change in direction This combined control leada
to loesee at all but the rated or design condition ot the
turbine (2$ Pbull )71)
This investigation dealt with an att mpt to better
turbine performance at all points of operation b y the
eatabliahment of separate controls over the rate of flow
and the d1J~ect1on ot the entering watebullbull
The only physical modification of the test tlutbine
was the insertion of flow restricting device in the dratt
tube
Ot primary interest were the trends in the change of
2
turbine performance with the amount ot draft tube tlow
area To this end complete turbine charaeteristiea were
not obtained tor 0ach device inserted in the draft tube
It was considered sutt1e1ent to obtain data tor the tull
speed range tor two representative gat openings one
greater and one less than the rated gate openingbull
Before proceeding with th report ot this 1nvest1gabull
t1on it 1a desirable to supply sa b ckground m terial
on reaction tw-blnes and their dratt tubes
B Raot1on 1rbinea
A hydraulic turbine is a device for converting the
energy in water to eohanical energy (6 Pbull 93lbull96S) furbull
b1nes may be loosely grouped into one of three elasse
impulsmiddote 1 reaot1on or propeller
An impulse turbine normally operates under a high head
and with a relatively sma~l amount ot watel in the converbull
sion or kinetic nergy to mechanical energy The propeller
turbine utilizes pressure energy to develop mechanical
energy while under a low head and p ss1ng a large amount of
waver
The reaction turbine lies somewhere between these two
extremes It changes both pressure and kinetic energy
while oper ting under a medium head with a moderate ount
opound water An example or a reaction turbine is pietur d in
Figure 1
lhe terms of high low small and so tomiddotrth are only
relative in sense A turbinebulls class1f1 eat1on is depenfent
upon its hoad rate of diacharge and speed of rot tion A
useful index tor turbine comparison (5 Pbull 825) is termed
specific speed and this ia a function of the rated ipeed
power output and head or the turbine The common range in
values ot speoitic speed ($ Pbull 826 ) tor each type ot tlirshy
bine is
Impulse J to SS tor one nozzle)Reaction bull 22 to 80 Propeller - 85 to 170
The development of t he reaction turbine began in the
early part or the nineteenth century (26 Pbull 1217bull1)6)
The trst efficient inward tlow turbine was de igned by
James B Francis an American in 1649bull For many years
turbine design was a matter of cutbullandbulltry in America an4
pure mathematical analysis 1n Europe It was not until the
two schools began exchanging ideas in the l$tter halt ot
the n1neteenth century that pronounced advancement was made
in the field
ObTioual7 the primary pux-pose ot any turbine inatallabull
t1on is t he production of power Added to this is the
restriction that the production or power must necessarily
be a controlled process An example of this is where the
turbine is direct-connected to an electric generator which
4
Figure 1 - 135 Inch Reaction Turbine
5
must operate at a constant speed or rotation even though _
the power demand ohangos In thiamp case the turbine nuet
be eap~able or producing a range of power output yet menshy
ta1n e eonetant speed
Speed regulation of the turbine iv accomplished by
means ot a governor (23 Pbull 24bull3-7) bull The contr-ol or regulashy
tion 1s indirect that i s the governor actually exereiaabull
control over the water in order to JJaintain e given speed
Co-ntrol over- the turbine end bence its speed and
power is the function ot a ring of movable wicket gates
located just upsttteam of the turbine runner These w1eket
gates 1n the process of opening and closing upon eeeh
0~1ar in a rotational manner actually control the amount
velocity and direction of tne water passing throu~~ them
C Draft Tubes
It has been found that the effeetive head on a reae
1l1on middotturbine is increased with the addi timiddoton of a draft tube
(3 Pbull 256bull264) Tne draft tube does thin by~
(1) Making a greater presaure d~op across the turbine
possible by the creation of a negative pressure at the
discharge or the runner and
2) DeoreaGing the k1net1e energy lost by increasing
the eross sectional area at exit
he draft tube permits the turbine runner to be
6
located above the tail race water surface without the
sacrifice of head However cavitation will cause pitting
of the turbine if the difference in elevation is too great
A common maximum elevation difference is 19 feet although
this figure is quite subject to modification between difshy
ferent installations (3 p middot 264-266)
There are many different types or draft tubes in use
today the choice or type being largely a matter or
economics (2$ p 368-370) A very common type particushy
larly among the smaller units is vertical with flaring
sides However the angle of flare is limited by the possishy
bility of separation of the flow from the sides In order
to achieve a certain discharge area the length of the tube
may be such as to require a great deal of excavation In
oases or this sort the cost of this excavation must be
balanced against a more elaborate design that does not
require as much excavation Other draft tubes in use
include the elbow hydracone and spreader types
Despite the differences found in construction and
design the draft tube must accomplish the desired objecshy
tives while offering a good hydraulic geometry to the flow
passing through it An inefficient draft tube defeats its
own purpose
Ohapter II
DISCUSSION ~ TURBINE LOSSES
A General
lhe head that 1a actually utilized by the turbine 1a
less than the effective bead as defined by equation ($) by
the amount that 1a lost due to mechanical and hydraulic
reasons
Mechanical loaaea are a function or the turbine 8p$ed
fhis ia not a lineaz- function but varies eomewhere between
N and N2 (3- Pbull 224)
Hydraulic losses encounteled in turbines ma- be subshy
divided aa to the location or occurrence (3 p 225-227) aa
fOllOW$S
(1) Penstock and scroll case
(2) Wicket gates
(3) Between wicket gates and turbine runner
(4) Runner passages
(5) Runner exit into draft tube
(6) Draft tube and
(7) At exit from the draft tube
The flow in the penstock scroll case wicket gates
runner passages and draft tube may be envisioned as
examples of flew in conventional pipes elbows and convergbull
1ng passages If this comparison may be made it could be
assumed that the losses encountered in these locations
would be proportional to vn ~ value ot N is normally2g
aesU111ed to be 2
he losses encountered between the wicket gates an4
the turbine runner and exit lossos are special cases which
will be discussed separately
B Shock toes_
The flow betwe n the wicket gat outlet and the runner
blade entrance is or particular 1nt rest because no direct
comparison vith common flow situations is obvious
Conaider the vector diagram (7 Pbull 7576) in Figure 2
The veetoo v1 is the absolute entering velocity of the
water and is fixed in magnitude and direction by the setbull
ting or the wicket gates The vector l11 1e the peripheztal
velocity of the runnel which tol any given turbine 1e
dependent only upon the turbine rotational speed The
combination of these two vectors ylelda the third vector
v1 which is the relative entering velocity ot the water
nere is only one setting ot the wicket gates for a
given turbine a peed that will produce an angle B1 which
coincides with the blade angle B1bull At other gate settings
the vector v1 will rotate and change in magnitude in such a
9
t ehion that B1 will beoome either greater or 1 sa than B1bull Th1 give rise to tbe phenomenon term d shock loasft
If B1 1a greater than B1 the relative ent ring veloebull
ityt v1 will have a compon~nt opposing the forward motion
of the runner The shock loss could be typified bullbull that
occasioned by direct impact or the water 0n the blade- If
E1 is lese than a] the vector l will overshoot the blade
and the flow will tend to eddy around the forward portion
or the blade tip
The shock loss can then be either due to impact or
eddying flow Since the area norm 1 to the radius at outlampt
of the w1eket gftee is essentially equ 1 to the area normnl
to the rad1u~ at the inlet to the turbine runner the combull
ponents ot vl and vl perpendicular to ul will b approxishy
mately equal This leads to the conclusion that xxbull ~epresenting the shock vector 1 parallel to Ulbull
For either the impact or eddy case the trigonometric
law of $1nee leads tot
XX
bull ul - sin (Bi-Al) vl eln Bi
It it 1a assumed that the energy lost in the shock 1a
the Telocity head ot the shock component XX then
10
VELOCITY VECTOR DIAGIWI
TYPES OF SHOCK LOSS
xbull X
IMPACT BDDJ
XX 1a Teloc1t7 caponent ot shock
Figure 2 - ~bine Runner Vector Diagram$ and Shock Loss Diagrams
11
2 shock loss (XX gt2g
C =sin (BimiddotAl)Let (1)sin Bi
(UlmiddotCV1)2Then shock loabull (2)- 2g
For a given gate opening C ia a constant ranging
from about 14 to 10 For a well designed wheel it is to middot
be expected that C would be approximately equal to U1V1
at rated conditions ie at point of maximum efficiency
This point will occur in the neighborhood of 3~ to 78
gate opening for moat turbines For overgate conditions
the angle A1 becomes larger so the value of C would
decrease For gate openings below rated conditions t he
angle A1 decreases and C would decrease One could expect
a fairly uniform decrease in t he value of C as the gate is
closed from t he overgate position
The velocity v1 is approximately constant for any
turbine speed since the area and rate of flow both decrease
fairly uniformly However for a given gate opening the
velocity V1 will decrease with increased turbine speed
From the foregoing comments and equation (2) the
following trends can be established
(1) For constant turbine speed the shook loss curve
will be close to parabolic in shape concave upward and
have its maximum near t he point of complete gate closure
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
I
bull
filE EPPEOI OF A VARIABLE DRAFT TUBE FLOW AREA
ON THE PERFORMANltJE OF A REAOTIO TURBINE
Chapter l
IITRODUClIOH
A hrpose and Scope of Invst1pt1on
Present day control of reaction turbines is accombull
pl1ahed by the use of wicket gates immediately- preceding
the turbine runner These gates otter an interrelated conbull
- trol to the quantity and direction ot the water entering
t-he runner ie a change in the amount ot flow will rebull
middot ult in a change in direction This combined control leada
to loesee at all but the rated or design condition ot the
turbine (2$ Pbull )71)
This investigation dealt with an att mpt to better
turbine performance at all points of operation b y the
eatabliahment of separate controls over the rate of flow
and the d1J~ect1on ot the entering watebullbull
The only physical modification of the test tlutbine
was the insertion of flow restricting device in the dratt
tube
Ot primary interest were the trends in the change of
2
turbine performance with the amount ot draft tube tlow
area To this end complete turbine charaeteristiea were
not obtained tor 0ach device inserted in the draft tube
It was considered sutt1e1ent to obtain data tor the tull
speed range tor two representative gat openings one
greater and one less than the rated gate openingbull
Before proceeding with th report ot this 1nvest1gabull
t1on it 1a desirable to supply sa b ckground m terial
on reaction tw-blnes and their dratt tubes
B Raot1on 1rbinea
A hydraulic turbine is a device for converting the
energy in water to eohanical energy (6 Pbull 93lbull96S) furbull
b1nes may be loosely grouped into one of three elasse
impulsmiddote 1 reaot1on or propeller
An impulse turbine normally operates under a high head
and with a relatively sma~l amount ot watel in the converbull
sion or kinetic nergy to mechanical energy The propeller
turbine utilizes pressure energy to develop mechanical
energy while under a low head and p ss1ng a large amount of
waver
The reaction turbine lies somewhere between these two
extremes It changes both pressure and kinetic energy
while oper ting under a medium head with a moderate ount
opound water An example or a reaction turbine is pietur d in
Figure 1
lhe terms of high low small and so tomiddotrth are only
relative in sense A turbinebulls class1f1 eat1on is depenfent
upon its hoad rate of diacharge and speed of rot tion A
useful index tor turbine comparison (5 Pbull 825) is termed
specific speed and this ia a function of the rated ipeed
power output and head or the turbine The common range in
values ot speoitic speed ($ Pbull 826 ) tor each type ot tlirshy
bine is
Impulse J to SS tor one nozzle)Reaction bull 22 to 80 Propeller - 85 to 170
The development of t he reaction turbine began in the
early part or the nineteenth century (26 Pbull 1217bull1)6)
The trst efficient inward tlow turbine was de igned by
James B Francis an American in 1649bull For many years
turbine design was a matter of cutbullandbulltry in America an4
pure mathematical analysis 1n Europe It was not until the
two schools began exchanging ideas in the l$tter halt ot
the n1neteenth century that pronounced advancement was made
in the field
ObTioual7 the primary pux-pose ot any turbine inatallabull
t1on is t he production of power Added to this is the
restriction that the production or power must necessarily
be a controlled process An example of this is where the
turbine is direct-connected to an electric generator which
4
Figure 1 - 135 Inch Reaction Turbine
5
must operate at a constant speed or rotation even though _
the power demand ohangos In thiamp case the turbine nuet
be eap~able or producing a range of power output yet menshy
ta1n e eonetant speed
Speed regulation of the turbine iv accomplished by
means ot a governor (23 Pbull 24bull3-7) bull The contr-ol or regulashy
tion 1s indirect that i s the governor actually exereiaabull
control over the water in order to JJaintain e given speed
Co-ntrol over- the turbine end bence its speed and
power is the function ot a ring of movable wicket gates
located just upsttteam of the turbine runner These w1eket
gates 1n the process of opening and closing upon eeeh
0~1ar in a rotational manner actually control the amount
velocity and direction of tne water passing throu~~ them
C Draft Tubes
It has been found that the effeetive head on a reae
1l1on middotturbine is increased with the addi timiddoton of a draft tube
(3 Pbull 256bull264) Tne draft tube does thin by~
(1) Making a greater presaure d~op across the turbine
possible by the creation of a negative pressure at the
discharge or the runner and
2) DeoreaGing the k1net1e energy lost by increasing
the eross sectional area at exit
he draft tube permits the turbine runner to be
6
located above the tail race water surface without the
sacrifice of head However cavitation will cause pitting
of the turbine if the difference in elevation is too great
A common maximum elevation difference is 19 feet although
this figure is quite subject to modification between difshy
ferent installations (3 p middot 264-266)
There are many different types or draft tubes in use
today the choice or type being largely a matter or
economics (2$ p 368-370) A very common type particushy
larly among the smaller units is vertical with flaring
sides However the angle of flare is limited by the possishy
bility of separation of the flow from the sides In order
to achieve a certain discharge area the length of the tube
may be such as to require a great deal of excavation In
oases or this sort the cost of this excavation must be
balanced against a more elaborate design that does not
require as much excavation Other draft tubes in use
include the elbow hydracone and spreader types
Despite the differences found in construction and
design the draft tube must accomplish the desired objecshy
tives while offering a good hydraulic geometry to the flow
passing through it An inefficient draft tube defeats its
own purpose
Ohapter II
DISCUSSION ~ TURBINE LOSSES
A General
lhe head that 1a actually utilized by the turbine 1a
less than the effective bead as defined by equation ($) by
the amount that 1a lost due to mechanical and hydraulic
reasons
Mechanical loaaea are a function or the turbine 8p$ed
fhis ia not a lineaz- function but varies eomewhere between
N and N2 (3- Pbull 224)
Hydraulic losses encounteled in turbines ma- be subshy
divided aa to the location or occurrence (3 p 225-227) aa
fOllOW$S
(1) Penstock and scroll case
(2) Wicket gates
(3) Between wicket gates and turbine runner
(4) Runner passages
(5) Runner exit into draft tube
(6) Draft tube and
(7) At exit from the draft tube
The flow in the penstock scroll case wicket gates
runner passages and draft tube may be envisioned as
examples of flew in conventional pipes elbows and convergbull
1ng passages If this comparison may be made it could be
assumed that the losses encountered in these locations
would be proportional to vn ~ value ot N is normally2g
aesU111ed to be 2
he losses encountered between the wicket gates an4
the turbine runner and exit lossos are special cases which
will be discussed separately
B Shock toes_
The flow betwe n the wicket gat outlet and the runner
blade entrance is or particular 1nt rest because no direct
comparison vith common flow situations is obvious
Conaider the vector diagram (7 Pbull 7576) in Figure 2
The veetoo v1 is the absolute entering velocity of the
water and is fixed in magnitude and direction by the setbull
ting or the wicket gates The vector l11 1e the peripheztal
velocity of the runnel which tol any given turbine 1e
dependent only upon the turbine rotational speed The
combination of these two vectors ylelda the third vector
v1 which is the relative entering velocity ot the water
nere is only one setting ot the wicket gates for a
given turbine a peed that will produce an angle B1 which
coincides with the blade angle B1bull At other gate settings
the vector v1 will rotate and change in magnitude in such a
9
t ehion that B1 will beoome either greater or 1 sa than B1bull Th1 give rise to tbe phenomenon term d shock loasft
If B1 1a greater than B1 the relative ent ring veloebull
ityt v1 will have a compon~nt opposing the forward motion
of the runner The shock loss could be typified bullbull that
occasioned by direct impact or the water 0n the blade- If
E1 is lese than a] the vector l will overshoot the blade
and the flow will tend to eddy around the forward portion
or the blade tip
The shock loss can then be either due to impact or
eddying flow Since the area norm 1 to the radius at outlampt
of the w1eket gftee is essentially equ 1 to the area normnl
to the rad1u~ at the inlet to the turbine runner the combull
ponents ot vl and vl perpendicular to ul will b approxishy
mately equal This leads to the conclusion that xxbull ~epresenting the shock vector 1 parallel to Ulbull
For either the impact or eddy case the trigonometric
law of $1nee leads tot
XX
bull ul - sin (Bi-Al) vl eln Bi
It it 1a assumed that the energy lost in the shock 1a
the Telocity head ot the shock component XX then
10
VELOCITY VECTOR DIAGIWI
TYPES OF SHOCK LOSS
xbull X
IMPACT BDDJ
XX 1a Teloc1t7 caponent ot shock
Figure 2 - ~bine Runner Vector Diagram$ and Shock Loss Diagrams
11
2 shock loss (XX gt2g
C =sin (BimiddotAl)Let (1)sin Bi
(UlmiddotCV1)2Then shock loabull (2)- 2g
For a given gate opening C ia a constant ranging
from about 14 to 10 For a well designed wheel it is to middot
be expected that C would be approximately equal to U1V1
at rated conditions ie at point of maximum efficiency
This point will occur in the neighborhood of 3~ to 78
gate opening for moat turbines For overgate conditions
the angle A1 becomes larger so the value of C would
decrease For gate openings below rated conditions t he
angle A1 decreases and C would decrease One could expect
a fairly uniform decrease in t he value of C as the gate is
closed from t he overgate position
The velocity v1 is approximately constant for any
turbine speed since the area and rate of flow both decrease
fairly uniformly However for a given gate opening the
velocity V1 will decrease with increased turbine speed
From the foregoing comments and equation (2) the
following trends can be established
(1) For constant turbine speed the shook loss curve
will be close to parabolic in shape concave upward and
have its maximum near t he point of complete gate closure
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
2
turbine performance with the amount ot draft tube tlow
area To this end complete turbine charaeteristiea were
not obtained tor 0ach device inserted in the draft tube
It was considered sutt1e1ent to obtain data tor the tull
speed range tor two representative gat openings one
greater and one less than the rated gate openingbull
Before proceeding with th report ot this 1nvest1gabull
t1on it 1a desirable to supply sa b ckground m terial
on reaction tw-blnes and their dratt tubes
B Raot1on 1rbinea
A hydraulic turbine is a device for converting the
energy in water to eohanical energy (6 Pbull 93lbull96S) furbull
b1nes may be loosely grouped into one of three elasse
impulsmiddote 1 reaot1on or propeller
An impulse turbine normally operates under a high head
and with a relatively sma~l amount ot watel in the converbull
sion or kinetic nergy to mechanical energy The propeller
turbine utilizes pressure energy to develop mechanical
energy while under a low head and p ss1ng a large amount of
waver
The reaction turbine lies somewhere between these two
extremes It changes both pressure and kinetic energy
while oper ting under a medium head with a moderate ount
opound water An example or a reaction turbine is pietur d in
Figure 1
lhe terms of high low small and so tomiddotrth are only
relative in sense A turbinebulls class1f1 eat1on is depenfent
upon its hoad rate of diacharge and speed of rot tion A
useful index tor turbine comparison (5 Pbull 825) is termed
specific speed and this ia a function of the rated ipeed
power output and head or the turbine The common range in
values ot speoitic speed ($ Pbull 826 ) tor each type ot tlirshy
bine is
Impulse J to SS tor one nozzle)Reaction bull 22 to 80 Propeller - 85 to 170
The development of t he reaction turbine began in the
early part or the nineteenth century (26 Pbull 1217bull1)6)
The trst efficient inward tlow turbine was de igned by
James B Francis an American in 1649bull For many years
turbine design was a matter of cutbullandbulltry in America an4
pure mathematical analysis 1n Europe It was not until the
two schools began exchanging ideas in the l$tter halt ot
the n1neteenth century that pronounced advancement was made
in the field
ObTioual7 the primary pux-pose ot any turbine inatallabull
t1on is t he production of power Added to this is the
restriction that the production or power must necessarily
be a controlled process An example of this is where the
turbine is direct-connected to an electric generator which
4
Figure 1 - 135 Inch Reaction Turbine
5
must operate at a constant speed or rotation even though _
the power demand ohangos In thiamp case the turbine nuet
be eap~able or producing a range of power output yet menshy
ta1n e eonetant speed
Speed regulation of the turbine iv accomplished by
means ot a governor (23 Pbull 24bull3-7) bull The contr-ol or regulashy
tion 1s indirect that i s the governor actually exereiaabull
control over the water in order to JJaintain e given speed
Co-ntrol over- the turbine end bence its speed and
power is the function ot a ring of movable wicket gates
located just upsttteam of the turbine runner These w1eket
gates 1n the process of opening and closing upon eeeh
0~1ar in a rotational manner actually control the amount
velocity and direction of tne water passing throu~~ them
C Draft Tubes
It has been found that the effeetive head on a reae
1l1on middotturbine is increased with the addi timiddoton of a draft tube
(3 Pbull 256bull264) Tne draft tube does thin by~
(1) Making a greater presaure d~op across the turbine
possible by the creation of a negative pressure at the
discharge or the runner and
2) DeoreaGing the k1net1e energy lost by increasing
the eross sectional area at exit
he draft tube permits the turbine runner to be
6
located above the tail race water surface without the
sacrifice of head However cavitation will cause pitting
of the turbine if the difference in elevation is too great
A common maximum elevation difference is 19 feet although
this figure is quite subject to modification between difshy
ferent installations (3 p middot 264-266)
There are many different types or draft tubes in use
today the choice or type being largely a matter or
economics (2$ p 368-370) A very common type particushy
larly among the smaller units is vertical with flaring
sides However the angle of flare is limited by the possishy
bility of separation of the flow from the sides In order
to achieve a certain discharge area the length of the tube
may be such as to require a great deal of excavation In
oases or this sort the cost of this excavation must be
balanced against a more elaborate design that does not
require as much excavation Other draft tubes in use
include the elbow hydracone and spreader types
Despite the differences found in construction and
design the draft tube must accomplish the desired objecshy
tives while offering a good hydraulic geometry to the flow
passing through it An inefficient draft tube defeats its
own purpose
Ohapter II
DISCUSSION ~ TURBINE LOSSES
A General
lhe head that 1a actually utilized by the turbine 1a
less than the effective bead as defined by equation ($) by
the amount that 1a lost due to mechanical and hydraulic
reasons
Mechanical loaaea are a function or the turbine 8p$ed
fhis ia not a lineaz- function but varies eomewhere between
N and N2 (3- Pbull 224)
Hydraulic losses encounteled in turbines ma- be subshy
divided aa to the location or occurrence (3 p 225-227) aa
fOllOW$S
(1) Penstock and scroll case
(2) Wicket gates
(3) Between wicket gates and turbine runner
(4) Runner passages
(5) Runner exit into draft tube
(6) Draft tube and
(7) At exit from the draft tube
The flow in the penstock scroll case wicket gates
runner passages and draft tube may be envisioned as
examples of flew in conventional pipes elbows and convergbull
1ng passages If this comparison may be made it could be
assumed that the losses encountered in these locations
would be proportional to vn ~ value ot N is normally2g
aesU111ed to be 2
he losses encountered between the wicket gates an4
the turbine runner and exit lossos are special cases which
will be discussed separately
B Shock toes_
The flow betwe n the wicket gat outlet and the runner
blade entrance is or particular 1nt rest because no direct
comparison vith common flow situations is obvious
Conaider the vector diagram (7 Pbull 7576) in Figure 2
The veetoo v1 is the absolute entering velocity of the
water and is fixed in magnitude and direction by the setbull
ting or the wicket gates The vector l11 1e the peripheztal
velocity of the runnel which tol any given turbine 1e
dependent only upon the turbine rotational speed The
combination of these two vectors ylelda the third vector
v1 which is the relative entering velocity ot the water
nere is only one setting ot the wicket gates for a
given turbine a peed that will produce an angle B1 which
coincides with the blade angle B1bull At other gate settings
the vector v1 will rotate and change in magnitude in such a
9
t ehion that B1 will beoome either greater or 1 sa than B1bull Th1 give rise to tbe phenomenon term d shock loasft
If B1 1a greater than B1 the relative ent ring veloebull
ityt v1 will have a compon~nt opposing the forward motion
of the runner The shock loss could be typified bullbull that
occasioned by direct impact or the water 0n the blade- If
E1 is lese than a] the vector l will overshoot the blade
and the flow will tend to eddy around the forward portion
or the blade tip
The shock loss can then be either due to impact or
eddying flow Since the area norm 1 to the radius at outlampt
of the w1eket gftee is essentially equ 1 to the area normnl
to the rad1u~ at the inlet to the turbine runner the combull
ponents ot vl and vl perpendicular to ul will b approxishy
mately equal This leads to the conclusion that xxbull ~epresenting the shock vector 1 parallel to Ulbull
For either the impact or eddy case the trigonometric
law of $1nee leads tot
XX
bull ul - sin (Bi-Al) vl eln Bi
It it 1a assumed that the energy lost in the shock 1a
the Telocity head ot the shock component XX then
10
VELOCITY VECTOR DIAGIWI
TYPES OF SHOCK LOSS
xbull X
IMPACT BDDJ
XX 1a Teloc1t7 caponent ot shock
Figure 2 - ~bine Runner Vector Diagram$ and Shock Loss Diagrams
11
2 shock loss (XX gt2g
C =sin (BimiddotAl)Let (1)sin Bi
(UlmiddotCV1)2Then shock loabull (2)- 2g
For a given gate opening C ia a constant ranging
from about 14 to 10 For a well designed wheel it is to middot
be expected that C would be approximately equal to U1V1
at rated conditions ie at point of maximum efficiency
This point will occur in the neighborhood of 3~ to 78
gate opening for moat turbines For overgate conditions
the angle A1 becomes larger so the value of C would
decrease For gate openings below rated conditions t he
angle A1 decreases and C would decrease One could expect
a fairly uniform decrease in t he value of C as the gate is
closed from t he overgate position
The velocity v1 is approximately constant for any
turbine speed since the area and rate of flow both decrease
fairly uniformly However for a given gate opening the
velocity V1 will decrease with increased turbine speed
From the foregoing comments and equation (2) the
following trends can be established
(1) For constant turbine speed the shook loss curve
will be close to parabolic in shape concave upward and
have its maximum near t he point of complete gate closure
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
Figure 1
lhe terms of high low small and so tomiddotrth are only
relative in sense A turbinebulls class1f1 eat1on is depenfent
upon its hoad rate of diacharge and speed of rot tion A
useful index tor turbine comparison (5 Pbull 825) is termed
specific speed and this ia a function of the rated ipeed
power output and head or the turbine The common range in
values ot speoitic speed ($ Pbull 826 ) tor each type ot tlirshy
bine is
Impulse J to SS tor one nozzle)Reaction bull 22 to 80 Propeller - 85 to 170
The development of t he reaction turbine began in the
early part or the nineteenth century (26 Pbull 1217bull1)6)
The trst efficient inward tlow turbine was de igned by
James B Francis an American in 1649bull For many years
turbine design was a matter of cutbullandbulltry in America an4
pure mathematical analysis 1n Europe It was not until the
two schools began exchanging ideas in the l$tter halt ot
the n1neteenth century that pronounced advancement was made
in the field
ObTioual7 the primary pux-pose ot any turbine inatallabull
t1on is t he production of power Added to this is the
restriction that the production or power must necessarily
be a controlled process An example of this is where the
turbine is direct-connected to an electric generator which
4
Figure 1 - 135 Inch Reaction Turbine
5
must operate at a constant speed or rotation even though _
the power demand ohangos In thiamp case the turbine nuet
be eap~able or producing a range of power output yet menshy
ta1n e eonetant speed
Speed regulation of the turbine iv accomplished by
means ot a governor (23 Pbull 24bull3-7) bull The contr-ol or regulashy
tion 1s indirect that i s the governor actually exereiaabull
control over the water in order to JJaintain e given speed
Co-ntrol over- the turbine end bence its speed and
power is the function ot a ring of movable wicket gates
located just upsttteam of the turbine runner These w1eket
gates 1n the process of opening and closing upon eeeh
0~1ar in a rotational manner actually control the amount
velocity and direction of tne water passing throu~~ them
C Draft Tubes
It has been found that the effeetive head on a reae
1l1on middotturbine is increased with the addi timiddoton of a draft tube
(3 Pbull 256bull264) Tne draft tube does thin by~
(1) Making a greater presaure d~op across the turbine
possible by the creation of a negative pressure at the
discharge or the runner and
2) DeoreaGing the k1net1e energy lost by increasing
the eross sectional area at exit
he draft tube permits the turbine runner to be
6
located above the tail race water surface without the
sacrifice of head However cavitation will cause pitting
of the turbine if the difference in elevation is too great
A common maximum elevation difference is 19 feet although
this figure is quite subject to modification between difshy
ferent installations (3 p middot 264-266)
There are many different types or draft tubes in use
today the choice or type being largely a matter or
economics (2$ p 368-370) A very common type particushy
larly among the smaller units is vertical with flaring
sides However the angle of flare is limited by the possishy
bility of separation of the flow from the sides In order
to achieve a certain discharge area the length of the tube
may be such as to require a great deal of excavation In
oases or this sort the cost of this excavation must be
balanced against a more elaborate design that does not
require as much excavation Other draft tubes in use
include the elbow hydracone and spreader types
Despite the differences found in construction and
design the draft tube must accomplish the desired objecshy
tives while offering a good hydraulic geometry to the flow
passing through it An inefficient draft tube defeats its
own purpose
Ohapter II
DISCUSSION ~ TURBINE LOSSES
A General
lhe head that 1a actually utilized by the turbine 1a
less than the effective bead as defined by equation ($) by
the amount that 1a lost due to mechanical and hydraulic
reasons
Mechanical loaaea are a function or the turbine 8p$ed
fhis ia not a lineaz- function but varies eomewhere between
N and N2 (3- Pbull 224)
Hydraulic losses encounteled in turbines ma- be subshy
divided aa to the location or occurrence (3 p 225-227) aa
fOllOW$S
(1) Penstock and scroll case
(2) Wicket gates
(3) Between wicket gates and turbine runner
(4) Runner passages
(5) Runner exit into draft tube
(6) Draft tube and
(7) At exit from the draft tube
The flow in the penstock scroll case wicket gates
runner passages and draft tube may be envisioned as
examples of flew in conventional pipes elbows and convergbull
1ng passages If this comparison may be made it could be
assumed that the losses encountered in these locations
would be proportional to vn ~ value ot N is normally2g
aesU111ed to be 2
he losses encountered between the wicket gates an4
the turbine runner and exit lossos are special cases which
will be discussed separately
B Shock toes_
The flow betwe n the wicket gat outlet and the runner
blade entrance is or particular 1nt rest because no direct
comparison vith common flow situations is obvious
Conaider the vector diagram (7 Pbull 7576) in Figure 2
The veetoo v1 is the absolute entering velocity of the
water and is fixed in magnitude and direction by the setbull
ting or the wicket gates The vector l11 1e the peripheztal
velocity of the runnel which tol any given turbine 1e
dependent only upon the turbine rotational speed The
combination of these two vectors ylelda the third vector
v1 which is the relative entering velocity ot the water
nere is only one setting ot the wicket gates for a
given turbine a peed that will produce an angle B1 which
coincides with the blade angle B1bull At other gate settings
the vector v1 will rotate and change in magnitude in such a
9
t ehion that B1 will beoome either greater or 1 sa than B1bull Th1 give rise to tbe phenomenon term d shock loasft
If B1 1a greater than B1 the relative ent ring veloebull
ityt v1 will have a compon~nt opposing the forward motion
of the runner The shock loss could be typified bullbull that
occasioned by direct impact or the water 0n the blade- If
E1 is lese than a] the vector l will overshoot the blade
and the flow will tend to eddy around the forward portion
or the blade tip
The shock loss can then be either due to impact or
eddying flow Since the area norm 1 to the radius at outlampt
of the w1eket gftee is essentially equ 1 to the area normnl
to the rad1u~ at the inlet to the turbine runner the combull
ponents ot vl and vl perpendicular to ul will b approxishy
mately equal This leads to the conclusion that xxbull ~epresenting the shock vector 1 parallel to Ulbull
For either the impact or eddy case the trigonometric
law of $1nee leads tot
XX
bull ul - sin (Bi-Al) vl eln Bi
It it 1a assumed that the energy lost in the shock 1a
the Telocity head ot the shock component XX then
10
VELOCITY VECTOR DIAGIWI
TYPES OF SHOCK LOSS
xbull X
IMPACT BDDJ
XX 1a Teloc1t7 caponent ot shock
Figure 2 - ~bine Runner Vector Diagram$ and Shock Loss Diagrams
11
2 shock loss (XX gt2g
C =sin (BimiddotAl)Let (1)sin Bi
(UlmiddotCV1)2Then shock loabull (2)- 2g
For a given gate opening C ia a constant ranging
from about 14 to 10 For a well designed wheel it is to middot
be expected that C would be approximately equal to U1V1
at rated conditions ie at point of maximum efficiency
This point will occur in the neighborhood of 3~ to 78
gate opening for moat turbines For overgate conditions
the angle A1 becomes larger so the value of C would
decrease For gate openings below rated conditions t he
angle A1 decreases and C would decrease One could expect
a fairly uniform decrease in t he value of C as the gate is
closed from t he overgate position
The velocity v1 is approximately constant for any
turbine speed since the area and rate of flow both decrease
fairly uniformly However for a given gate opening the
velocity V1 will decrease with increased turbine speed
From the foregoing comments and equation (2) the
following trends can be established
(1) For constant turbine speed the shook loss curve
will be close to parabolic in shape concave upward and
have its maximum near t he point of complete gate closure
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
4
Figure 1 - 135 Inch Reaction Turbine
5
must operate at a constant speed or rotation even though _
the power demand ohangos In thiamp case the turbine nuet
be eap~able or producing a range of power output yet menshy
ta1n e eonetant speed
Speed regulation of the turbine iv accomplished by
means ot a governor (23 Pbull 24bull3-7) bull The contr-ol or regulashy
tion 1s indirect that i s the governor actually exereiaabull
control over the water in order to JJaintain e given speed
Co-ntrol over- the turbine end bence its speed and
power is the function ot a ring of movable wicket gates
located just upsttteam of the turbine runner These w1eket
gates 1n the process of opening and closing upon eeeh
0~1ar in a rotational manner actually control the amount
velocity and direction of tne water passing throu~~ them
C Draft Tubes
It has been found that the effeetive head on a reae
1l1on middotturbine is increased with the addi timiddoton of a draft tube
(3 Pbull 256bull264) Tne draft tube does thin by~
(1) Making a greater presaure d~op across the turbine
possible by the creation of a negative pressure at the
discharge or the runner and
2) DeoreaGing the k1net1e energy lost by increasing
the eross sectional area at exit
he draft tube permits the turbine runner to be
6
located above the tail race water surface without the
sacrifice of head However cavitation will cause pitting
of the turbine if the difference in elevation is too great
A common maximum elevation difference is 19 feet although
this figure is quite subject to modification between difshy
ferent installations (3 p middot 264-266)
There are many different types or draft tubes in use
today the choice or type being largely a matter or
economics (2$ p 368-370) A very common type particushy
larly among the smaller units is vertical with flaring
sides However the angle of flare is limited by the possishy
bility of separation of the flow from the sides In order
to achieve a certain discharge area the length of the tube
may be such as to require a great deal of excavation In
oases or this sort the cost of this excavation must be
balanced against a more elaborate design that does not
require as much excavation Other draft tubes in use
include the elbow hydracone and spreader types
Despite the differences found in construction and
design the draft tube must accomplish the desired objecshy
tives while offering a good hydraulic geometry to the flow
passing through it An inefficient draft tube defeats its
own purpose
Ohapter II
DISCUSSION ~ TURBINE LOSSES
A General
lhe head that 1a actually utilized by the turbine 1a
less than the effective bead as defined by equation ($) by
the amount that 1a lost due to mechanical and hydraulic
reasons
Mechanical loaaea are a function or the turbine 8p$ed
fhis ia not a lineaz- function but varies eomewhere between
N and N2 (3- Pbull 224)
Hydraulic losses encounteled in turbines ma- be subshy
divided aa to the location or occurrence (3 p 225-227) aa
fOllOW$S
(1) Penstock and scroll case
(2) Wicket gates
(3) Between wicket gates and turbine runner
(4) Runner passages
(5) Runner exit into draft tube
(6) Draft tube and
(7) At exit from the draft tube
The flow in the penstock scroll case wicket gates
runner passages and draft tube may be envisioned as
examples of flew in conventional pipes elbows and convergbull
1ng passages If this comparison may be made it could be
assumed that the losses encountered in these locations
would be proportional to vn ~ value ot N is normally2g
aesU111ed to be 2
he losses encountered between the wicket gates an4
the turbine runner and exit lossos are special cases which
will be discussed separately
B Shock toes_
The flow betwe n the wicket gat outlet and the runner
blade entrance is or particular 1nt rest because no direct
comparison vith common flow situations is obvious
Conaider the vector diagram (7 Pbull 7576) in Figure 2
The veetoo v1 is the absolute entering velocity of the
water and is fixed in magnitude and direction by the setbull
ting or the wicket gates The vector l11 1e the peripheztal
velocity of the runnel which tol any given turbine 1e
dependent only upon the turbine rotational speed The
combination of these two vectors ylelda the third vector
v1 which is the relative entering velocity ot the water
nere is only one setting ot the wicket gates for a
given turbine a peed that will produce an angle B1 which
coincides with the blade angle B1bull At other gate settings
the vector v1 will rotate and change in magnitude in such a
9
t ehion that B1 will beoome either greater or 1 sa than B1bull Th1 give rise to tbe phenomenon term d shock loasft
If B1 1a greater than B1 the relative ent ring veloebull
ityt v1 will have a compon~nt opposing the forward motion
of the runner The shock loss could be typified bullbull that
occasioned by direct impact or the water 0n the blade- If
E1 is lese than a] the vector l will overshoot the blade
and the flow will tend to eddy around the forward portion
or the blade tip
The shock loss can then be either due to impact or
eddying flow Since the area norm 1 to the radius at outlampt
of the w1eket gftee is essentially equ 1 to the area normnl
to the rad1u~ at the inlet to the turbine runner the combull
ponents ot vl and vl perpendicular to ul will b approxishy
mately equal This leads to the conclusion that xxbull ~epresenting the shock vector 1 parallel to Ulbull
For either the impact or eddy case the trigonometric
law of $1nee leads tot
XX
bull ul - sin (Bi-Al) vl eln Bi
It it 1a assumed that the energy lost in the shock 1a
the Telocity head ot the shock component XX then
10
VELOCITY VECTOR DIAGIWI
TYPES OF SHOCK LOSS
xbull X
IMPACT BDDJ
XX 1a Teloc1t7 caponent ot shock
Figure 2 - ~bine Runner Vector Diagram$ and Shock Loss Diagrams
11
2 shock loss (XX gt2g
C =sin (BimiddotAl)Let (1)sin Bi
(UlmiddotCV1)2Then shock loabull (2)- 2g
For a given gate opening C ia a constant ranging
from about 14 to 10 For a well designed wheel it is to middot
be expected that C would be approximately equal to U1V1
at rated conditions ie at point of maximum efficiency
This point will occur in the neighborhood of 3~ to 78
gate opening for moat turbines For overgate conditions
the angle A1 becomes larger so the value of C would
decrease For gate openings below rated conditions t he
angle A1 decreases and C would decrease One could expect
a fairly uniform decrease in t he value of C as the gate is
closed from t he overgate position
The velocity v1 is approximately constant for any
turbine speed since the area and rate of flow both decrease
fairly uniformly However for a given gate opening the
velocity V1 will decrease with increased turbine speed
From the foregoing comments and equation (2) the
following trends can be established
(1) For constant turbine speed the shook loss curve
will be close to parabolic in shape concave upward and
have its maximum near t he point of complete gate closure
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
5
must operate at a constant speed or rotation even though _
the power demand ohangos In thiamp case the turbine nuet
be eap~able or producing a range of power output yet menshy
ta1n e eonetant speed
Speed regulation of the turbine iv accomplished by
means ot a governor (23 Pbull 24bull3-7) bull The contr-ol or regulashy
tion 1s indirect that i s the governor actually exereiaabull
control over the water in order to JJaintain e given speed
Co-ntrol over- the turbine end bence its speed and
power is the function ot a ring of movable wicket gates
located just upsttteam of the turbine runner These w1eket
gates 1n the process of opening and closing upon eeeh
0~1ar in a rotational manner actually control the amount
velocity and direction of tne water passing throu~~ them
C Draft Tubes
It has been found that the effeetive head on a reae
1l1on middotturbine is increased with the addi timiddoton of a draft tube
(3 Pbull 256bull264) Tne draft tube does thin by~
(1) Making a greater presaure d~op across the turbine
possible by the creation of a negative pressure at the
discharge or the runner and
2) DeoreaGing the k1net1e energy lost by increasing
the eross sectional area at exit
he draft tube permits the turbine runner to be
6
located above the tail race water surface without the
sacrifice of head However cavitation will cause pitting
of the turbine if the difference in elevation is too great
A common maximum elevation difference is 19 feet although
this figure is quite subject to modification between difshy
ferent installations (3 p middot 264-266)
There are many different types or draft tubes in use
today the choice or type being largely a matter or
economics (2$ p 368-370) A very common type particushy
larly among the smaller units is vertical with flaring
sides However the angle of flare is limited by the possishy
bility of separation of the flow from the sides In order
to achieve a certain discharge area the length of the tube
may be such as to require a great deal of excavation In
oases or this sort the cost of this excavation must be
balanced against a more elaborate design that does not
require as much excavation Other draft tubes in use
include the elbow hydracone and spreader types
Despite the differences found in construction and
design the draft tube must accomplish the desired objecshy
tives while offering a good hydraulic geometry to the flow
passing through it An inefficient draft tube defeats its
own purpose
Ohapter II
DISCUSSION ~ TURBINE LOSSES
A General
lhe head that 1a actually utilized by the turbine 1a
less than the effective bead as defined by equation ($) by
the amount that 1a lost due to mechanical and hydraulic
reasons
Mechanical loaaea are a function or the turbine 8p$ed
fhis ia not a lineaz- function but varies eomewhere between
N and N2 (3- Pbull 224)
Hydraulic losses encounteled in turbines ma- be subshy
divided aa to the location or occurrence (3 p 225-227) aa
fOllOW$S
(1) Penstock and scroll case
(2) Wicket gates
(3) Between wicket gates and turbine runner
(4) Runner passages
(5) Runner exit into draft tube
(6) Draft tube and
(7) At exit from the draft tube
The flow in the penstock scroll case wicket gates
runner passages and draft tube may be envisioned as
examples of flew in conventional pipes elbows and convergbull
1ng passages If this comparison may be made it could be
assumed that the losses encountered in these locations
would be proportional to vn ~ value ot N is normally2g
aesU111ed to be 2
he losses encountered between the wicket gates an4
the turbine runner and exit lossos are special cases which
will be discussed separately
B Shock toes_
The flow betwe n the wicket gat outlet and the runner
blade entrance is or particular 1nt rest because no direct
comparison vith common flow situations is obvious
Conaider the vector diagram (7 Pbull 7576) in Figure 2
The veetoo v1 is the absolute entering velocity of the
water and is fixed in magnitude and direction by the setbull
ting or the wicket gates The vector l11 1e the peripheztal
velocity of the runnel which tol any given turbine 1e
dependent only upon the turbine rotational speed The
combination of these two vectors ylelda the third vector
v1 which is the relative entering velocity ot the water
nere is only one setting ot the wicket gates for a
given turbine a peed that will produce an angle B1 which
coincides with the blade angle B1bull At other gate settings
the vector v1 will rotate and change in magnitude in such a
9
t ehion that B1 will beoome either greater or 1 sa than B1bull Th1 give rise to tbe phenomenon term d shock loasft
If B1 1a greater than B1 the relative ent ring veloebull
ityt v1 will have a compon~nt opposing the forward motion
of the runner The shock loss could be typified bullbull that
occasioned by direct impact or the water 0n the blade- If
E1 is lese than a] the vector l will overshoot the blade
and the flow will tend to eddy around the forward portion
or the blade tip
The shock loss can then be either due to impact or
eddying flow Since the area norm 1 to the radius at outlampt
of the w1eket gftee is essentially equ 1 to the area normnl
to the rad1u~ at the inlet to the turbine runner the combull
ponents ot vl and vl perpendicular to ul will b approxishy
mately equal This leads to the conclusion that xxbull ~epresenting the shock vector 1 parallel to Ulbull
For either the impact or eddy case the trigonometric
law of $1nee leads tot
XX
bull ul - sin (Bi-Al) vl eln Bi
It it 1a assumed that the energy lost in the shock 1a
the Telocity head ot the shock component XX then
10
VELOCITY VECTOR DIAGIWI
TYPES OF SHOCK LOSS
xbull X
IMPACT BDDJ
XX 1a Teloc1t7 caponent ot shock
Figure 2 - ~bine Runner Vector Diagram$ and Shock Loss Diagrams
11
2 shock loss (XX gt2g
C =sin (BimiddotAl)Let (1)sin Bi
(UlmiddotCV1)2Then shock loabull (2)- 2g
For a given gate opening C ia a constant ranging
from about 14 to 10 For a well designed wheel it is to middot
be expected that C would be approximately equal to U1V1
at rated conditions ie at point of maximum efficiency
This point will occur in the neighborhood of 3~ to 78
gate opening for moat turbines For overgate conditions
the angle A1 becomes larger so the value of C would
decrease For gate openings below rated conditions t he
angle A1 decreases and C would decrease One could expect
a fairly uniform decrease in t he value of C as the gate is
closed from t he overgate position
The velocity v1 is approximately constant for any
turbine speed since the area and rate of flow both decrease
fairly uniformly However for a given gate opening the
velocity V1 will decrease with increased turbine speed
From the foregoing comments and equation (2) the
following trends can be established
(1) For constant turbine speed the shook loss curve
will be close to parabolic in shape concave upward and
have its maximum near t he point of complete gate closure
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
6
located above the tail race water surface without the
sacrifice of head However cavitation will cause pitting
of the turbine if the difference in elevation is too great
A common maximum elevation difference is 19 feet although
this figure is quite subject to modification between difshy
ferent installations (3 p middot 264-266)
There are many different types or draft tubes in use
today the choice or type being largely a matter or
economics (2$ p 368-370) A very common type particushy
larly among the smaller units is vertical with flaring
sides However the angle of flare is limited by the possishy
bility of separation of the flow from the sides In order
to achieve a certain discharge area the length of the tube
may be such as to require a great deal of excavation In
oases or this sort the cost of this excavation must be
balanced against a more elaborate design that does not
require as much excavation Other draft tubes in use
include the elbow hydracone and spreader types
Despite the differences found in construction and
design the draft tube must accomplish the desired objecshy
tives while offering a good hydraulic geometry to the flow
passing through it An inefficient draft tube defeats its
own purpose
Ohapter II
DISCUSSION ~ TURBINE LOSSES
A General
lhe head that 1a actually utilized by the turbine 1a
less than the effective bead as defined by equation ($) by
the amount that 1a lost due to mechanical and hydraulic
reasons
Mechanical loaaea are a function or the turbine 8p$ed
fhis ia not a lineaz- function but varies eomewhere between
N and N2 (3- Pbull 224)
Hydraulic losses encounteled in turbines ma- be subshy
divided aa to the location or occurrence (3 p 225-227) aa
fOllOW$S
(1) Penstock and scroll case
(2) Wicket gates
(3) Between wicket gates and turbine runner
(4) Runner passages
(5) Runner exit into draft tube
(6) Draft tube and
(7) At exit from the draft tube
The flow in the penstock scroll case wicket gates
runner passages and draft tube may be envisioned as
examples of flew in conventional pipes elbows and convergbull
1ng passages If this comparison may be made it could be
assumed that the losses encountered in these locations
would be proportional to vn ~ value ot N is normally2g
aesU111ed to be 2
he losses encountered between the wicket gates an4
the turbine runner and exit lossos are special cases which
will be discussed separately
B Shock toes_
The flow betwe n the wicket gat outlet and the runner
blade entrance is or particular 1nt rest because no direct
comparison vith common flow situations is obvious
Conaider the vector diagram (7 Pbull 7576) in Figure 2
The veetoo v1 is the absolute entering velocity of the
water and is fixed in magnitude and direction by the setbull
ting or the wicket gates The vector l11 1e the peripheztal
velocity of the runnel which tol any given turbine 1e
dependent only upon the turbine rotational speed The
combination of these two vectors ylelda the third vector
v1 which is the relative entering velocity ot the water
nere is only one setting ot the wicket gates for a
given turbine a peed that will produce an angle B1 which
coincides with the blade angle B1bull At other gate settings
the vector v1 will rotate and change in magnitude in such a
9
t ehion that B1 will beoome either greater or 1 sa than B1bull Th1 give rise to tbe phenomenon term d shock loasft
If B1 1a greater than B1 the relative ent ring veloebull
ityt v1 will have a compon~nt opposing the forward motion
of the runner The shock loss could be typified bullbull that
occasioned by direct impact or the water 0n the blade- If
E1 is lese than a] the vector l will overshoot the blade
and the flow will tend to eddy around the forward portion
or the blade tip
The shock loss can then be either due to impact or
eddying flow Since the area norm 1 to the radius at outlampt
of the w1eket gftee is essentially equ 1 to the area normnl
to the rad1u~ at the inlet to the turbine runner the combull
ponents ot vl and vl perpendicular to ul will b approxishy
mately equal This leads to the conclusion that xxbull ~epresenting the shock vector 1 parallel to Ulbull
For either the impact or eddy case the trigonometric
law of $1nee leads tot
XX
bull ul - sin (Bi-Al) vl eln Bi
It it 1a assumed that the energy lost in the shock 1a
the Telocity head ot the shock component XX then
10
VELOCITY VECTOR DIAGIWI
TYPES OF SHOCK LOSS
xbull X
IMPACT BDDJ
XX 1a Teloc1t7 caponent ot shock
Figure 2 - ~bine Runner Vector Diagram$ and Shock Loss Diagrams
11
2 shock loss (XX gt2g
C =sin (BimiddotAl)Let (1)sin Bi
(UlmiddotCV1)2Then shock loabull (2)- 2g
For a given gate opening C ia a constant ranging
from about 14 to 10 For a well designed wheel it is to middot
be expected that C would be approximately equal to U1V1
at rated conditions ie at point of maximum efficiency
This point will occur in the neighborhood of 3~ to 78
gate opening for moat turbines For overgate conditions
the angle A1 becomes larger so the value of C would
decrease For gate openings below rated conditions t he
angle A1 decreases and C would decrease One could expect
a fairly uniform decrease in t he value of C as the gate is
closed from t he overgate position
The velocity v1 is approximately constant for any
turbine speed since the area and rate of flow both decrease
fairly uniformly However for a given gate opening the
velocity V1 will decrease with increased turbine speed
From the foregoing comments and equation (2) the
following trends can be established
(1) For constant turbine speed the shook loss curve
will be close to parabolic in shape concave upward and
have its maximum near t he point of complete gate closure
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
Ohapter II
DISCUSSION ~ TURBINE LOSSES
A General
lhe head that 1a actually utilized by the turbine 1a
less than the effective bead as defined by equation ($) by
the amount that 1a lost due to mechanical and hydraulic
reasons
Mechanical loaaea are a function or the turbine 8p$ed
fhis ia not a lineaz- function but varies eomewhere between
N and N2 (3- Pbull 224)
Hydraulic losses encounteled in turbines ma- be subshy
divided aa to the location or occurrence (3 p 225-227) aa
fOllOW$S
(1) Penstock and scroll case
(2) Wicket gates
(3) Between wicket gates and turbine runner
(4) Runner passages
(5) Runner exit into draft tube
(6) Draft tube and
(7) At exit from the draft tube
The flow in the penstock scroll case wicket gates
runner passages and draft tube may be envisioned as
examples of flew in conventional pipes elbows and convergbull
1ng passages If this comparison may be made it could be
assumed that the losses encountered in these locations
would be proportional to vn ~ value ot N is normally2g
aesU111ed to be 2
he losses encountered between the wicket gates an4
the turbine runner and exit lossos are special cases which
will be discussed separately
B Shock toes_
The flow betwe n the wicket gat outlet and the runner
blade entrance is or particular 1nt rest because no direct
comparison vith common flow situations is obvious
Conaider the vector diagram (7 Pbull 7576) in Figure 2
The veetoo v1 is the absolute entering velocity of the
water and is fixed in magnitude and direction by the setbull
ting or the wicket gates The vector l11 1e the peripheztal
velocity of the runnel which tol any given turbine 1e
dependent only upon the turbine rotational speed The
combination of these two vectors ylelda the third vector
v1 which is the relative entering velocity ot the water
nere is only one setting ot the wicket gates for a
given turbine a peed that will produce an angle B1 which
coincides with the blade angle B1bull At other gate settings
the vector v1 will rotate and change in magnitude in such a
9
t ehion that B1 will beoome either greater or 1 sa than B1bull Th1 give rise to tbe phenomenon term d shock loasft
If B1 1a greater than B1 the relative ent ring veloebull
ityt v1 will have a compon~nt opposing the forward motion
of the runner The shock loss could be typified bullbull that
occasioned by direct impact or the water 0n the blade- If
E1 is lese than a] the vector l will overshoot the blade
and the flow will tend to eddy around the forward portion
or the blade tip
The shock loss can then be either due to impact or
eddying flow Since the area norm 1 to the radius at outlampt
of the w1eket gftee is essentially equ 1 to the area normnl
to the rad1u~ at the inlet to the turbine runner the combull
ponents ot vl and vl perpendicular to ul will b approxishy
mately equal This leads to the conclusion that xxbull ~epresenting the shock vector 1 parallel to Ulbull
For either the impact or eddy case the trigonometric
law of $1nee leads tot
XX
bull ul - sin (Bi-Al) vl eln Bi
It it 1a assumed that the energy lost in the shock 1a
the Telocity head ot the shock component XX then
10
VELOCITY VECTOR DIAGIWI
TYPES OF SHOCK LOSS
xbull X
IMPACT BDDJ
XX 1a Teloc1t7 caponent ot shock
Figure 2 - ~bine Runner Vector Diagram$ and Shock Loss Diagrams
11
2 shock loss (XX gt2g
C =sin (BimiddotAl)Let (1)sin Bi
(UlmiddotCV1)2Then shock loabull (2)- 2g
For a given gate opening C ia a constant ranging
from about 14 to 10 For a well designed wheel it is to middot
be expected that C would be approximately equal to U1V1
at rated conditions ie at point of maximum efficiency
This point will occur in the neighborhood of 3~ to 78
gate opening for moat turbines For overgate conditions
the angle A1 becomes larger so the value of C would
decrease For gate openings below rated conditions t he
angle A1 decreases and C would decrease One could expect
a fairly uniform decrease in t he value of C as the gate is
closed from t he overgate position
The velocity v1 is approximately constant for any
turbine speed since the area and rate of flow both decrease
fairly uniformly However for a given gate opening the
velocity V1 will decrease with increased turbine speed
From the foregoing comments and equation (2) the
following trends can be established
(1) For constant turbine speed the shook loss curve
will be close to parabolic in shape concave upward and
have its maximum near t he point of complete gate closure
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
examples of flew in conventional pipes elbows and convergbull
1ng passages If this comparison may be made it could be
assumed that the losses encountered in these locations
would be proportional to vn ~ value ot N is normally2g
aesU111ed to be 2
he losses encountered between the wicket gates an4
the turbine runner and exit lossos are special cases which
will be discussed separately
B Shock toes_
The flow betwe n the wicket gat outlet and the runner
blade entrance is or particular 1nt rest because no direct
comparison vith common flow situations is obvious
Conaider the vector diagram (7 Pbull 7576) in Figure 2
The veetoo v1 is the absolute entering velocity of the
water and is fixed in magnitude and direction by the setbull
ting or the wicket gates The vector l11 1e the peripheztal
velocity of the runnel which tol any given turbine 1e
dependent only upon the turbine rotational speed The
combination of these two vectors ylelda the third vector
v1 which is the relative entering velocity ot the water
nere is only one setting ot the wicket gates for a
given turbine a peed that will produce an angle B1 which
coincides with the blade angle B1bull At other gate settings
the vector v1 will rotate and change in magnitude in such a
9
t ehion that B1 will beoome either greater or 1 sa than B1bull Th1 give rise to tbe phenomenon term d shock loasft
If B1 1a greater than B1 the relative ent ring veloebull
ityt v1 will have a compon~nt opposing the forward motion
of the runner The shock loss could be typified bullbull that
occasioned by direct impact or the water 0n the blade- If
E1 is lese than a] the vector l will overshoot the blade
and the flow will tend to eddy around the forward portion
or the blade tip
The shock loss can then be either due to impact or
eddying flow Since the area norm 1 to the radius at outlampt
of the w1eket gftee is essentially equ 1 to the area normnl
to the rad1u~ at the inlet to the turbine runner the combull
ponents ot vl and vl perpendicular to ul will b approxishy
mately equal This leads to the conclusion that xxbull ~epresenting the shock vector 1 parallel to Ulbull
For either the impact or eddy case the trigonometric
law of $1nee leads tot
XX
bull ul - sin (Bi-Al) vl eln Bi
It it 1a assumed that the energy lost in the shock 1a
the Telocity head ot the shock component XX then
10
VELOCITY VECTOR DIAGIWI
TYPES OF SHOCK LOSS
xbull X
IMPACT BDDJ
XX 1a Teloc1t7 caponent ot shock
Figure 2 - ~bine Runner Vector Diagram$ and Shock Loss Diagrams
11
2 shock loss (XX gt2g
C =sin (BimiddotAl)Let (1)sin Bi
(UlmiddotCV1)2Then shock loabull (2)- 2g
For a given gate opening C ia a constant ranging
from about 14 to 10 For a well designed wheel it is to middot
be expected that C would be approximately equal to U1V1
at rated conditions ie at point of maximum efficiency
This point will occur in the neighborhood of 3~ to 78
gate opening for moat turbines For overgate conditions
the angle A1 becomes larger so the value of C would
decrease For gate openings below rated conditions t he
angle A1 decreases and C would decrease One could expect
a fairly uniform decrease in t he value of C as the gate is
closed from t he overgate position
The velocity v1 is approximately constant for any
turbine speed since the area and rate of flow both decrease
fairly uniformly However for a given gate opening the
velocity V1 will decrease with increased turbine speed
From the foregoing comments and equation (2) the
following trends can be established
(1) For constant turbine speed the shook loss curve
will be close to parabolic in shape concave upward and
have its maximum near t he point of complete gate closure
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
9
t ehion that B1 will beoome either greater or 1 sa than B1bull Th1 give rise to tbe phenomenon term d shock loasft
If B1 1a greater than B1 the relative ent ring veloebull
ityt v1 will have a compon~nt opposing the forward motion
of the runner The shock loss could be typified bullbull that
occasioned by direct impact or the water 0n the blade- If
E1 is lese than a] the vector l will overshoot the blade
and the flow will tend to eddy around the forward portion
or the blade tip
The shock loss can then be either due to impact or
eddying flow Since the area norm 1 to the radius at outlampt
of the w1eket gftee is essentially equ 1 to the area normnl
to the rad1u~ at the inlet to the turbine runner the combull
ponents ot vl and vl perpendicular to ul will b approxishy
mately equal This leads to the conclusion that xxbull ~epresenting the shock vector 1 parallel to Ulbull
For either the impact or eddy case the trigonometric
law of $1nee leads tot
XX
bull ul - sin (Bi-Al) vl eln Bi
It it 1a assumed that the energy lost in the shock 1a
the Telocity head ot the shock component XX then
10
VELOCITY VECTOR DIAGIWI
TYPES OF SHOCK LOSS
xbull X
IMPACT BDDJ
XX 1a Teloc1t7 caponent ot shock
Figure 2 - ~bine Runner Vector Diagram$ and Shock Loss Diagrams
11
2 shock loss (XX gt2g
C =sin (BimiddotAl)Let (1)sin Bi
(UlmiddotCV1)2Then shock loabull (2)- 2g
For a given gate opening C ia a constant ranging
from about 14 to 10 For a well designed wheel it is to middot
be expected that C would be approximately equal to U1V1
at rated conditions ie at point of maximum efficiency
This point will occur in the neighborhood of 3~ to 78
gate opening for moat turbines For overgate conditions
the angle A1 becomes larger so the value of C would
decrease For gate openings below rated conditions t he
angle A1 decreases and C would decrease One could expect
a fairly uniform decrease in t he value of C as the gate is
closed from t he overgate position
The velocity v1 is approximately constant for any
turbine speed since the area and rate of flow both decrease
fairly uniformly However for a given gate opening the
velocity V1 will decrease with increased turbine speed
From the foregoing comments and equation (2) the
following trends can be established
(1) For constant turbine speed the shook loss curve
will be close to parabolic in shape concave upward and
have its maximum near t he point of complete gate closure
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
10
VELOCITY VECTOR DIAGIWI
TYPES OF SHOCK LOSS
xbull X
IMPACT BDDJ
XX 1a Teloc1t7 caponent ot shock
Figure 2 - ~bine Runner Vector Diagram$ and Shock Loss Diagrams
11
2 shock loss (XX gt2g
C =sin (BimiddotAl)Let (1)sin Bi
(UlmiddotCV1)2Then shock loabull (2)- 2g
For a given gate opening C ia a constant ranging
from about 14 to 10 For a well designed wheel it is to middot
be expected that C would be approximately equal to U1V1
at rated conditions ie at point of maximum efficiency
This point will occur in the neighborhood of 3~ to 78
gate opening for moat turbines For overgate conditions
the angle A1 becomes larger so the value of C would
decrease For gate openings below rated conditions t he
angle A1 decreases and C would decrease One could expect
a fairly uniform decrease in t he value of C as the gate is
closed from t he overgate position
The velocity v1 is approximately constant for any
turbine speed since the area and rate of flow both decrease
fairly uniformly However for a given gate opening the
velocity V1 will decrease with increased turbine speed
From the foregoing comments and equation (2) the
following trends can be established
(1) For constant turbine speed the shook loss curve
will be close to parabolic in shape concave upward and
have its maximum near t he point of complete gate closure
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
11
2 shock loss (XX gt2g
C =sin (BimiddotAl)Let (1)sin Bi
(UlmiddotCV1)2Then shock loabull (2)- 2g
For a given gate opening C ia a constant ranging
from about 14 to 10 For a well designed wheel it is to middot
be expected that C would be approximately equal to U1V1
at rated conditions ie at point of maximum efficiency
This point will occur in the neighborhood of 3~ to 78
gate opening for moat turbines For overgate conditions
the angle A1 becomes larger so the value of C would
decrease For gate openings below rated conditions t he
angle A1 decreases and C would decrease One could expect
a fairly uniform decrease in t he value of C as the gate is
closed from t he overgate position
The velocity v1 is approximately constant for any
turbine speed since the area and rate of flow both decrease
fairly uniformly However for a given gate opening the
velocity V1 will decrease with increased turbine speed
From the foregoing comments and equation (2) the
following trends can be established
(1) For constant turbine speed the shook loss curve
will be close to parabolic in shape concave upward and
have its maximum near t he point of complete gate closure
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
--
12
and its minimum near the rated gate position
(2) For conatant gate opening the shook loss curve
will approximate a symmetrical parabola with its vertex
the point of minimum loas located at the rated condition
of operation (7 Pbull 79)
c Exit Loas
It can be seen from Figure 2 that the exit loss from
the turbine would be v222g if no draft tube were present
The addition of a draft tube permits the gradual reduction
of velocity by an increase in cross sectional area between
the exit of the runner and the exit from the draft tube
The exit loss and the frictional loss encountered in
the draft tube may be placed together in the expression
m va2 (3)Exit Loss ~---2g
For the ideal case of no friction in the draft tube
m is equal to the square of the ratio of the area at exit
from the runner to the area at exit from the draft tube
In an actual turbine installation however friction
will change the value of m (7 p 84-85) to somewhere
between that for the ideal case and a maximum ot 10
In the interest of maintaining a minimum exit loss
the turbine should be designed and operated so the velocity
V2 will be minimum This will occur when the discharge
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
13
vector is at right angles to the tangent to the runnerbull
ie the angle A2 1e ninety degree bull It ia to be expected
that this condition will be tultilled near the design con~
d1t1ons ot the ~bine
Current design praetiee 1 to have a small component
ot v2 in th$ direction of turbine rotation at rated condibull
tion$ ltS p 938)
For a constant turbine speed the d1seharg or exit
loss is ess nti lly a constant
For a constant gate opening the exit lo s curve is
aptrroximately a symmetrical pa~abola with ita vert x the
point or minimum loss located at a slightly lowe~ speed
th n the turbine rated speed (7 Pbull 79)
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
Chapter III
PROPOSAL OP ALlERMAlE MFTBO 0 CO TROL-A lz ~ Location 2 Control
Thua tar only practice and theoretical aspects appemiddotrbull
taining to present day turbinea have been d1acuaaed It
haa been presented that control over the ~bine ia ezerbull
oiaed b y manipulation of the wicket gatea located 11101led1bull
ately preceding the runner These gate - upon rotation
modify both the magn1tu4e and the direction ot the entering
velocit7 Moreover it has be n shown that a simultaneous
change in these two variables leads to inefficient operabull
tion by the introduction of shock loss he farther the
point of operation a from the rated conditione the more
aerioua ia the ahock loss encountered
Any attempt to better turbine pertorance at other
than rated conditione and tbne flatten the top ot the
etticieney hill8 must concentrate upon the lessening ot
the ahock loaa It 1a a aumed that 1 provement in the
scroll case gates and runners would lequ1re sueh pertecbull
tion 1n machine work and metal$ as to be prohibitively
expensive
It ie surmised that any move to elblinate eYen parbull
tially the shock loss would require separate control ovel
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
l$
the flow and gate exit angle Since it is improbable that
d1~ect1on could be controlled at any location other than
where the gatea are situated in current turbines it will
be assumed that guide vanes will be necessary regardlesa or the method used to control the rate of flow
The primary purpose ot th se guide vanes 1s that or control over the direction ot the incoming water They
should be free to rotate in much the same manner as ordibull
nary wicket gates in order to exercise control over th
turbine speed
If the rate ot tlov is to be controlled elsewhere it
must be modified either in the penstock or the draft tube
Devices that could be used are standard valves gates
variable orifices variable venturi sections and associated
flow regulating schemes
Alauming it were decided to locate such a device upbull
stream of the turbine it would be necessary to allow disbull
tance tor the flow picture to become reestablished prior to
entry to the turbine A contused flow making transit of
the turbine passages would only contribute additional loesbull
ea Such a distance allowance would be perbapa 20 to So
diameters (2$ Pbull 119-123) In large penstocka th1a would
repreaent a considerable distance Which from the viewbull
points ot convenience and control would be undesirable
Attempts to ascertain the effect or additional tlov
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
16
reduc ion at the wicket gatctsmiddot wae ade 1n the lfadraulioe middot
Laboratory of Oregon St middot te College in 1933 (20) Three
d1tterent thode ot reducins the tlow were t~ied
(l) Locking in the cloeed position pairs or wicket
gatea located opposite to eaeh o~er on the -periphery ot
the wheel
(2) Locking adjacent gates in an open position by
inserting blocks of wood between them and
()) Suocess1vely looking adjacent gates in the closed
position
The results indicated a arked reduction in both power
and efficiency when compared to the curves tor normal gate
operation However it was demonstrated that it was poae1bull
ble to ahitt the power and tfieiency curve ill relation to
turbine apeed lbis important feature will be diacussed
later
ihe main conclusion of the investigation was that conbull
trol by the conyent1onal wick t gates was auper1or to other
methode egtt control exercised at the gates the aelvebullbull
It would app$ar that the bebullt location tor flow conshy
trol would be in the draft tube since none of the objecbull
tiona prev1ously mentioned wou~d eziat there
As bas been stated previously the sole object or the
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
17
18
turbine is to produce power as etfic1ently as possible
The equation tor the power output of a turbine () Pbull 227)
PaWHe HP (4)55o bull bull Assuming the head 1a constant and a g te located in
the draft tube decreases bhe rate ot flow the power eu
only be increased if the etticiency increases
The ettective head Gn the turbine 1s conventionally
d r1ned as the difference between the auma ot the elevashy
tion head pressure head and velocity head at the entrance
to the turbine casing and the tailrace ($ Pbull 872)
lt ie recognized that the theoretical treatment ot
shock loss as given is highly approximate and serves only
to dictate certain trenda For example the area at xit
rom the wicket g tea CfUl be measuPed with some exactness
but there exists no guarantee that the wateP particles will
complet-ely fill the apace oz- will exit at the establiahed
g te angle The same can be said of the exit trom the
runner blades AssUIlptiona were implied which would indishy
cate that all water particles passing a given croea section
ampH traveling at the same velocity in the same direction
the e alone are autt1c1ent to show 11m1tationa in a theoretbull
1eal approach to the problem
Assume a turbine with ordinary wicket gates tor oonbull
trol compared gainst the same turbine with a gate in the
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
18
draft tttbe tor supplampment1ng control or the rate ot rlow
Let it also be assumed that the two turbines are opershy
ating at the same point It 1s desirable to predict relabull
tive performance of the two turbines 1 this point of
operation is such that edd7 s hook loss ot reasonable proshy
portions is present in the fir t turbine
~ tull erteot of the shock loss will be exper1 need
by- the fir t turbine
lhe second turbine will derive certain advantages 11
the gate in the draft tube is adjusted to reduce the tlov
1n the proper amount Since they vary a the square ot
the veloo1t7bull the lossabull in the aeroll case wiomiddotket gate
and runner passages will decx-ease aetet-r1ng to Figure 2 1
it can be seen that a decreased velocity v1 w-ill reduce the
eddy shock losa
The ent loss in the dJtaft tube of the second turbine
will be the sum ot the tr1ct1onal loss and the velocity
head at ex1t The velocity head dissipated will be greater
due to the closing action or the gate but the reduoed
t~ictional loss which ia a tunction ot the rate of tlow1
will partially balance this
It 1a entirely possible that the net reduction in
losses in the second turbine will lead to a greater ettibull
oiency and more power output than 4eYeloped by the first
turbine
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
19
In Figure 3 the plot ot power output against turbine
speed for Curv A~ represents the typical family of curvea
tor a reaction turbine Th b st sp ed is the locus ot
points connecting maximum eft1oiency at each gate opening
The operating speed is the coZUJtant turbine apeed which
passes through the point ot maximum efC1ciencr of the turbull
bine The plot of turbine efficiency against power output
for Curve A is also ahown
It the turbine with flow regulation in the dratt tube
oan demonstrate superior power and efficiency at part loads
the effect would be the same as a shifting or the power
curves toward the condition shown fop Curve B 11 Thisbull
illustrates th ultimate case of the uperpoait1on of best
and operating speeds It will be noted that the pet-form~
of the turbine ot Ourve Bu 1a better than that of CUrve
A at part loads because of ita ability to sustain a relabull
tively high etticienoy ovel a Wider range of power output
o Reguireaegts tort Test Velitication
It is desired to deterra1ne the effect on the turbine
performance b) the addition of a gate in the dratt tube
Th step in the teit will bet
(1 To determine the power output and efficiency ot
the turbine tor wicket gate settings above and below rated
conditione for a wide range ot speed
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
20
CURVEAbull
TURBINE SPSBD TURBID SPEKD
POIBR OOTPOl
Figure 3 - Turbine Performance Curves
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
21
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
22
(2 peat (l) with the gate installed in the drat
tube
(3) middot Converting middot all data to a constant head compare the
powere and effioiencies at the same wicket gate setting and
turbin speed tor the two cbullses
If the ddition or the gate indicates an improvement
in power output and efficiency and the powe~ curve shifts
to the right along the turbine apeed scale the advantage
ot draft tube con~ol of the flow will hav been demonshy
strated
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
Chapter IV
A E9J11pment
ih turbine used in this test is lJ 5 1nch Pelton
reaction turbine with a rated output ot 30 horsepower under
a head of 56 feet at a speed ot 720 reYolutiona per minute
Views of this turbine are hovn in Figures S and 6 The
turbine is installed on a concrete pad located over an open
channel in the Hydraulics Laboratory at Oregon State Colshy
lege The date of manufacture of this turbine was 1915
The water was delivered to the turbine from a sump
reservoir by two pumps operating 1n parallel Each pump 1a
an 8 inch Pelton double suction centrifugal pump witb a
rating of l$00 gallons per minute at a head ot 75 teet with
a speed ot 1175 revolutions per minute Tbe inlet tlange
ot tne turbine is $pprox1mately 18 feet above the center
line of the pump
A direct current generator was coupled to the turbine
to receive tne power d veloped as shown in Figures 4 and 7 The generator is a Spr gue Electrodynamometer rated at SS horsepower with a speed range of 7$0 to l$00 revolut1one
per minute The classification is type LO 26A 2)0 volta
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
Figure 5 - View of Test Turbine
Figure 6 ~ View of Test Turbine
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
and 149 amperes lbe generator ti ld was aepar tely
excited using direct current from a motor g n r tor ampt
(l$ p 4~8)
The power output of the generator waa dissipated in
the water rheostat (3 p 488-489) shown in Figures 9 and
10 The galvanized tank contain d water ot variable d pth
on an electrode ot cast iron m aauring 1bull x 1 x 1
In the initial installation of the turbine it was
intended that the power output should be measured with a
Prony brak bull For th purpoa68 or this teat it was decided
that the brake was too instable and the generator was
substituted The platform for raising the generator the
nee asary two teet for alignment was built out of available
material In this case heavy laminated wood blocks reiashy
torced with other timbers were used and bolted through the
concrete deck (11 Pbull 36-$7)
Due to the light concrete deck the lack ot mas in
the platform and the slight misalignment in the flexible
coupling ao e vibration waa encountered It seemed to
ncr aae linearly to a maximum at the speed of bout 750
revolutions per minute Above this speed no vibPation was
noticeable The vibration waa not se~ere and does not
appear to have materially affected the test results
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
26
B Intrumentat1on ~ eaeur1ng Devices
The pressure head at inlet to the turbine vaa meaave4
bymeane ot two )6 inch waterbullmeroury manometerbull connected
in series as shown in Figure 8
The terminal voltage ot the generator vas meaeured by
a laboratory voltDleter with a range to )00 yolta and callbull
brated to within 15 Yolta
The armature current bull and hence the line current was
measured by a laboratory ammeter with a range to 150 amperea
and callbrated to w1 thin o 7S amperes
Tae rate ot tlow was established by weight and time
meaeurementa The weighing ank has a capacity ot 121 000
poundsJ the weight belng indicated by Toledo direct reading
scales Timing was done with a hand atop watch with clivibull
aion ot 02 second
he ~ater level in the tailrace was dete~1ned by a
hook gauge lhie was read to the nearest 001 toot
The turbine and generator speeds were eaaured by a
hand tachometer The technique of almost cont1nuoua readbull
ings of the speed gave an error ot no more than 5 revolubull
tiona per minute
c Operational Procedure
Atter the water level in the aump was checked to
insure an adequate auppl7 the puapa were primed and
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0
27
Figure 7 - Test Generator and Plattorm
Figure middot8- Instrument Board and Field Rheostat
28
started After venting they were valved for operation 1n
parallel
The motor generator set was started to supply the
field current and the circuit breaker was closed Water
wa added to the water rheostat to the level shown in
Figure 10 ~ field current wae minimized by cutting in
all the f ield resistance in the field rheostat of Figure 8
The l2 inch gate valve shown in Figures 5 and 6 waa
slowly opened and the turbine and generator brought up to
speed The 12 inch gat valve and turbine were vented and
the pumps were checked to insure neither had lost ita prime
lhe water rheostat offers very steady load 1f the
water level is essentially constant and the water temperabull
ture 1a fixed () p 488~89) In order to maintain this
constant temperature it was decided not to circulate the
water in the rheostat but rather to allow the water to
boil thua achieving the desired result A standing wave
was set up on the face ot the electrode by the boiling
action but a atable load was eatablished except at very
low water leYels where th11 agitation led to fluctuationa
in the line current
After putting the turbine and generator on the line
maximum power was dissipated in the rheostat by redueing
the turbine speed to between oSO and Soo revolutions per
minute Salt vas added to the rheoetat wat r to increasemiddot
29
Figure 9 - View of Water Rheostat
Figure 10 - View of Water Rheostat
Separate Field ExcitationFrom Motor-Generator set Compound Water-Mercury
---shy
re Manometer
I Q)
~ 0
~
Book Gauge
Open Channel
I
Slap Reservoir
Figure 11 - Wat~r Flow Diagram and Electrical Layout
31
waiting pe~iod ot perhaps an h~ followed
while the boiling point or the water wbulls reacbe4 During
this ti+ne the manometer was vented end eheoked electrical
measur1ng 1nstlUments were connected end the hook gauge was
adjusted tor elevation
It required about two- houtte tor the generator to reach
its normal operating tempe-ratu~e_ After the water in the
rheostat and generator had reached their operating temperabull
turea it was possible to begin the taking of data
The only vaPiable which was controlled wee the turbineshy
generator speed However the upper l1ut1t of safe line
current was slightly over 100 ampJilPampPes and the eireuit
breaker would open when the current reached lOS ~ere bull
Control was exercised by means ot regulating the water
level and salt 1n the water rheo tat and the res1stsnoe of
the tield rheost t~
The etfeet ot each type ot regulation on the three
variables is shown below
Volta Aaperebull Speed
Inc Dec Inc Dee~ Inc Dec
Wa~e1 Level Inc Dec~ X
X X X X
X
Salt Concentration
Inc Dec X
X X X X
X
field Resistance
Inc Dec
X X
X X
X X
32
Jlot all methods gave the ame amount ot change in a
given variable and a period of experiment and trial led to
the following scheme starting the rune with the lowest
turbine speed the water level was high with a high amount
ot salt and the field resistance was cut completely out
Aa it became necessary to increase the speed tor each
aucceasive run either cutting in t he field resistance
decreasing the salt concentration or lowering the Vater
level would produce the desired result However decreasbull
1ng the salt concentration had to be done Without a net
gain in water which led to a tluahing procedure that was
not particularly good because cold water was introduced
which required time to heat to the boiling point Cutting
1n additional field resistance was a good method but th1a
increased the amperage possibly to the point of opening
the circuit breaker Lowering the water level was aatiashy
factol1 until the level got too low causing the current
fluctuation previously mentioned Actually it turned out
that a combination of lowering the water level and cutting
field resistance in would carry the speed from ita minimum
to 1ts maximum value it the proper choice were made each
time the speed waa to be changed At the conclusion of
each aet of runs at a high speed the water level would be
low and the field resistance high
33
TURBINE
PAD AND DECK
TAILRACE
WATER SURFACamp
CONCRETE
DRAFT TU1B INSERTS
7 5( DRAFr TUBE
FLltJI ARIA
5~ DRAFT TUBE
FLOI ARSA
Figure 12 - Sketch of Draft Tube and Test Inserts
34
Figure 13 - View of Draft Tube Insert
Figure 14 - View of Draft Tube Insert
D c __ ~s_middot hedu_le of
A number was assigned to each run The fi~st number
applies to the draft tube tlow areas
1 bull 100~ flow area or 0~ oonatriction
2 - 7S tlow area or 2$ conatr1ct1on
3 SoC flow area or so~ constriction
The second number refers to the wicket gate openings
9 over gate opening
6 bull intermediate gate opening
4 bull one h lt gate opening
The third number 14entif1ea the location of the particular
1Wl in a set ot rona made at a given dratt tube tlow area
and wicket gate opening
fnua run number 1bull4bull10 would identity this as the
tenth run ot a set made at halt gate with 75 ot the draft
tube t1ow area
Rune w re made tor a g1yen dratt tube condition
Firat tor tull 41-aft tube flow area seta ot rune were
made for the overgate halt gate and intermediate gate
conditione An insert was placed in t he draft tube and
rune based on the same gate conditions were made tor the
7S~ draft tube flow area case The insert was then changed
to allow only $~ draft tube flow area
The inserts are sketched 1n Figure 12 and photographed
ln Flgurea 13 and 14 They oonaisted of circula~ segments
36
or l2 ineh plywood mount 4 on wooden legs 10 inches high
The 1nse7te were placed in position and secured by th use
ot a-clamps on the legs and the outside ot the bottom of
the draft tube The obvious disadvantage to this method
waa the neoeasity tor draining the water from the tailrace
tor a change ot 1naert The advantage vas of course the
simplicity ot design and construction
Chapter V
DATA-A Original Data
The normal data-taking crew consisted or two men
Assuming adjustments having been made to secure a certain
turbine speed (aee section on Operational Procedure) one
man would take semi-continuous speed readings with the hand
tachometer until a state or rotational equilibrium was
reached This could be only a period or two minutes up to
ten or tifteen minutes As soon as steady speed was
assured the data taking would begin The second man went
to the weighing tank Where a minimum ot three weighingamp
were made The requirement was to get three consecutive
readings such that the ditterence between tbe smallest and
largest time did not exceed 04 seconds The time to
collect a given weight ot water was then assumed to be the
arithmetic average of the three times He then went to the
hook gauge determined the hook elevation and then
recorded the data on the data sheets The first man meanshy
while had taken readings of the line voltage line current
and manometers and checked the turbine speed by multiple
readings During the length of the run all values were
38
checked to determine mean values for recording
The minimum length of one run was about five minutes
If one or more measure ants tended to drift during the run
all values wer discarded and a new run began as soon aa
qu111br1um was stabl1shedo
B -0-al_e_u_l_a_t--d Data
The h d on the tu~bine 1 defined by
($)
The maxtmwm velocity V4 was equal to about o8 tampet per
secon4 which makes it a negligible quantity when converted
into velocity head
An engineerbulla level was used to deterine the d1ffePshy
ence 1n elevation between the compound water-mercury manoshy
meter and the hook gauge Using this value the equation
for turbine bead becomes
where z4 is the hook gauge reading
The rate of flow 1 cent
w weight or water collected average time to collect
The inlet velocity v1 vas calculated by dividing the
weight rate or flow by the specific weight of water and the
)9
area ot ~e inlet pipe This was equivalent to dividing
the weight rate of flow by 490 Then the power input to the turbine is equal to
WHpin rri
10 (6)
Also
(P ~ut) Turbine
(P out) + Generator
(P lost) Generator
The power output of the generator is simplJ the
produot ot the terminal voltage and the armature (line)
curPent The power lost in the generator can be subdivided
into copper losses and stray power losses lo evaluate
these cunes based on losses of an identical generator
11leampsured by the Department ot Mechanical Engineering were
used The loss curves are reppoduced in part in Figures
15 and 16
Determination ot generator losses proceeds as tollowau
(1) From Figure 15 detem1ne the vo1tage drop in the
armature circuit using the temperatures of 1220 F and the
meaaured current
(2) The induced voltage is t~e sum of the terminal
voltage and the voltage drop 1n the armature circuit
() Entering the induced voltage and the turbine speed
into Figure 16 the stray power loss can be determined
(4) The copper lose can be evaluated from Figure 1$
using the measured current and the temperatlll-e of 1220 P
40
25 ~------~--------~--------~------~
U) -U) - 20
f-4 ~
-~ -gt 0
0
VOLTAGE DROP
~ - i -
- bullbullbull bull - -middot-middot -+ ~- + -t--+ ~ - ~ middotbull ~-~ middott- -+----- _ -4 middotmiddot- --~-+-t---r~~ ~--+t-t- - ---t-c-++~-ulf--
0 50 75 100
Figure 15 - Curves of Generator Voltage Drop and Copper Loss
41
1200
1000
800
600
800
0
0
~-
middot--~ 1shy --1 + bull l
100
I -
150 200
IIDOOED VOLTAGB (VOLTS)
Figure 16 - Curves of Generator Stray Power Loss
_ j
-bullshy -L---- shy middot -shy
250
- r
42
(5) The generator los os equal the sum of the eopp r
loss and stray power loss
~e efficiency or the turbine is taken as
etticiency u e =P out (8)Pin
~ample pound Determ1n1gg turbine Power Output
The following data are taken trom that ot Run 1-9-1
Line voltage 1040 volts Line current 870 amperesSpeed 355 revolutions per minute
The induced voltage 1a determined as follows
Line voltage 1040
Voltage drop 90 using Figure 15 with line current of 870 amperes and temperature ot 122 degrees)
Induced Toltage 1130 volta
The power output of the turbine is determined as follows
Generator output 90$0 (line voltage z line current)
Oopper loss 7 (using Figure 15 with line current of 870 amperes and temperatUe or 122 degrees)
Stray power lose 470 (using Figure 16 with speed ot 355 revolutions per miDUte and induced voltage or 1130 volts)
Turbine power output 9527 vatta
or turbine power output 1s 12z2 horsepower
43
The conversion of the calculated data to a constant
head is based on the conventional assumption of constant
efficiency regardless of turbine head For a constant head
ot 81 teet a purely arbitrary figure the tollowing relashy
tionships are ass1lJiled to be true
I ____L (9) (i)l72
(10)
For these two values the specific a peed may be combull
putedt
N t Jt VPt (11)8 243
Chapter VI
~RESULTS
A -Pr_e_ae_n_t_a_t_t_o~n g Reaultbull
Graphical presentation ot the results ot this te1t
are given as follows
Figure 17 -Turbine characteristics with 100~ dratt
tuba 1low area
Figure 18 - Turbine characteristics with 7S dratt
tube tlow area
Figure 19 bull Comparison ot power and etticiency at
over gate conditions between 100 and
75~ draft tube flow area
Figure 20 bull COZQparison of power and ettic1ency at
halt gate conditions between 100~ and
7S~ draft tube flow area
Figure 21 bull Comparison of power and etticiency at
over gate condition between 100~ and
So dratt tube tlow area
Figure 22 - Comparison in variation ot apec1t1c
speed between 100 and 75~ dratt tube
tlow area
50
45
20
-bull - 1--shy40
bull J-~ 30
~ ex
~ 20
~~ ~ -)q
I
~ - _
- -
10~ OF DRAFT TUBE FL(Jif AREA
CONSTANT HEAD OF 8l FEST10
POIER OUTPUT EFFICIENCY SPECIFIC SPEED
0 ~--------------_--------~------~------~ 400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 17 - Turbine Char~cteristics with 100 Draft Tube Flow Area
50
46
-bulllle
~ 7 ~ OF DRAFt TUBE FLOW AREA
0 -~~-rl C05STAMT BEAD OF 81 mET 1J~
POIER OOTPUT ---+- ---o ~_H EFFICIDCY ~ I shy
bull ql SPECIFIC SPEKD - ~ -
bull ~ J 10 L rmiddotr- r- -
bullz- I
~~ 30 ~~--~----~~-
20 ~ ~ middot-shy
26
~~ 25
~0 ~r-----i (
Tbull -bullshy
400 600 800 1000 1200 1400
TURBINE SPEED (R PK )
Figure 18 -Turbine Characteristics with 75 Draft Tube Flow Area
47
EFFICIENCY 60
1-----shy
-~ 50~--~--~~-~middot middot middot middot r~-~----~~~~---4~-r~-~~gtt
II
POWER~ J ~ bull bull
u I
sH
40~------+-------+---- -~~--~~-~~~~
~----~rl 1 bull
I
I
0~--------------~------_------~--------
~ -OVER GATE CONDITION
COIJSTANT HEAD OF 81 FEET
0 o 10~ DRAFt TUBE
_-- _ 7~ DRAFT TUBamp FLON AREA II
10_~-----+--------r-------r----~~
400 600 800 1000 1200 1400
TURBINE SPEED (RPM)
Figure 19 middot - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Over Gate Conshydition
48
t
bull --4 r ~- ~ middot~
70 1-----------+-~~~~~+middot ~ ~~ middot middot -~~--~~--------~~----~-+1
-~-
Atbull bull
lla-
60
amp0
40
20
10
oampOO
t _ - - ~-+- - -~-
l2 GATB COJIDITIOJJ
COJISTABT HJW) OF 81 JBET
o 0 lOQ( DRAFl TUB8 FLOI AREA
e-- - e 75 DRAFT TUBE FLOW AREA
800 1000
- r-
~
TURBIbull SPBIID (RPII)
Figure 20 - Comparison between 75 and 100 Draft Tube Flow Areas of Power and Efficiency at Half Gate Conshydition
49
60
50
-40
bull 30
IIQbull
20
10
0
400
- t - ~
EFFICIENCY
_J bull - bull bull
~ r r middot t -+ shy L -t -
OVER GAD COliDITIOI
CONSTABT BEAD OF 8l FBB
o o 10~ DRAFt TUBE FLOI ADA middot--- 5~ DRAF TUBE FLQPi AREA
600 800 1000 1200
Figure 21 -Comparison between 50~ and 100~ Draft Tube Flow Areas of Power and Efficiency at Ove~ Gate Conshydition
50
25
20
15
10
0
Figure 22
~- T -4 -t- -l --~-
t-~ I
middot --~- t ~---- _ __ _ + --
----~- --r-- --
~-=J-~-=-~ -==~ _ ~- -- ---f---1 - shy
CONSTANT HEAD OF 81 FEBT
o--o 1~ DRAFT TUBE FLltll AREA
75C DRMT TUBK FLCIJ AREAmiddot--middot-middot 600 800 1000
TURBINE SPEED (RPK)
Comparison of Specific Speeds for 75 and 100 Draft Tube Flow Areas
51
B Discussion 2 Result
Consideration of Figures 17 and 18 indicates the
overall eftioi ncy pattern or hill is significantly or
rounded for the 7$~ flow area than for the 100~ flow area
bia implies a greateP efficiency is possible at speeds
leas than or greater than design speed with an insert in
the draft tube However the muilDum efficiency is lemiddotas
Direct comparison at over gate conditions is made in
Figure 19 ~e same general trend is noted tor both the
etticiency and power curves for the 7$~ flow area case
The eurves show higher values at overspeed than do the
correaponding cWvea for the 100 flow area case It ia
not clear whether the curves have been shifted by the dratt
tube constriction or whether the curves simply bulge past
the normal curves at both overspeed and underspeed condishy
tions The power curves apparently peak near the aeme
point bullalthough maximum power is still obtained with the
normal draft tube area
For the comparison at halt gate operation shown in
Figure 20 a general improvement has apparently been made
by restriction of the draft tube flow area At every speed
the etticienoy and the power is greater for the restricted
tlow case The two ett1o1ency curves and two power curvea
are practically parallel throughout the speed range ot
teat
As the flou aroa i e decreased still farther a s1gn1
ticant change appears Reterr1ng to Figllle 211 tor the $0
flow area curves it a obvious that exit losses have
become excessive at the overgate condition because the
efficiency and power are everywhere leas than tor the case
of normal draf t tube area
Earlier it was pointed out t hat 1t the r esult s 1nd1bull
eated an increase in both power and ef tieiency- t hen it
could be assumed tha t the additional los s i ntroduced with
the draft tube insert is less than the diminished losses
due to leas shock losa and water passage losses For the
places where both the efficiency and power have been
increased we can assume that the insert has improved turshy
bine performance
For the places where the power haa been decreased
nothing can be said as to the elimination of ampbock loss
because the new lose present with the drat tube insert has
overshadowed any gains in eftecti Ve head upatJ-eam of the
insert
Near the peak of the efficiency hill howeve~ it may
be pointed out t hat shock loaa ie a minimum with a normal
draft tube and the insert merely adds an additional loss
with the resultant decrease in maximum efficiency tor the
7$~ flow area case
Perhaps the most s1gn1ticant set of eurves is shown aa
53
Figure 22 In this graph values of specific speed tor the
75 and 100~ flow area cases for both over gate and one
halt gate openings are plotted against turbine speed At
every speed and both gate openings the value ot specific
speed for th 75~ flow area case is greater than that for
the 100 t1ow area ease
Since the head is a constant for both situations this
may be interpreted in either of two ways trom equation
(11)
(1) For the same turbine apeed restriction of the
draft tube t1ow area resulted in greater turbine power
(2) For the same power amputput the turbine with 75~
draft tube flow area operated at a greater speed than did
the one with 100 flow area
Since the required diameter of a turbine varies
inversely with the speed the second interpretation could
be stated such that a smaller turbine could be used to
develop the same power output
Whether viewed trom the aspect of increased power
greater speed or reduced size the performance of the turshy
bine with reduced draft tube flow area is superior to that
with the nolmal flow are in the draft tube
The curve of specmiddotific speed versus turbine speed for
the so draft tube flow area case at over gate cond1t1ona
was not included in Figure 22 This curve lies below that
for the 100~ flow area c se at all speeds
In elaboration ot the second interpretation of Figure
22 attention is directed to the relative magnitudes ot
increased apee1f1c speed tor the two gate openings Assumbull
ing that the increase in specific speed implies a shift ot
the power curve to the right along the turbine speed scale
the power curve would be shifted more tor tbe halt gate
opening than tor the over gate opening
It thia trend could be extrapolated to the other gate
openings the tendency can be seen tor the line ot beat
speed to rotate toward the line of the operating speed as
illustrated in FigtU-e ) The advantage of this has already
been discussed
This particular turbine has a low specific speed tor a
reaction turbine Aa the rated value of apecitic apeed tor
reaction turbines increases the line ot beat speed departs
even more radically from the line of operating bullpeed It a
test similar to this were conducted on a reaction turbine
ot gleater specific speed it is pJobable t hat the rotation
ot the line of beat apeed would become more p~onounced
The scheme used in th1a teat had two obvious dr wbull
backs The first was the decision to leave all the wicket
gamiddottes installed tor all conditions ot the draft tube
These gates predominated in control of the tlow The
inserts added to the draft tube merely acted as auxiliary
55
contrGla
The aecond drawback was the choice or device to place
in the draft tube The reasons foll selection of this type
of device have been previously mentioned It is to be
anticipated that adaptation ot dratt tube flow control
would result 1n a better device for an actual turbine
installation Such apparatus might take the form of a
pneumatic bladder or a h7drau11oally operated variable
venturi section in the draft tube It is conceivable that
the gate as used in this test might be adapted also
Chapter VII
OONCLtJSIOfS
From the results of this test the following eonolubull
e1ona aa to the effect ot a variable draft tube flow area
on the performance or a r action turbine may be drawn
(1) The effect ot a variable draft tube tlow area 1a
generally favorable upon the operat1Gn ot a reaction turbull
bine because or the tendency tor the line or beat speed to
rotate toward the line ot operation This resulte in
better performance of the turbine at partbullloads
(2) he etf1o1ency eh111 tor the turbine beeomaa JDore
tlat at the top leading to a smaller max1JilWD effic1enc7
but e reater etticieney at other pointe of operation with
the insertion ot an auxiliary control ror the rate ot tlov
in the draft tube
(3) The power output of the turbine will increase at
over speed over gate conditione as well a at part gate
conditions with the proper amount or draft tube eonatr1cbull
tion or flow
(4) It is possible to eliminate at least partially
eddy type shock loss by tho introduction ot flow control
in the draft tube
BIBLIOGRAPBl
1 Addison Herbert A treatise on applied h-draul1cs New York Wiley 1954 724 Pbull
2 Allen o M and I A Winter middot Co111parative testa on experimental draft tubes Tranaact1ons ot the American ociety ot Civil Engineers 87t893bull970 1924
3 Barrows a E Water power engineering 3d ed ew York McGraw-Bill 1943 791 Pbull
Bovet G A Modern trenda in hydraulic turbine design4middot in Europe Tranaactions of the American Society ot Mechanical Engineera 75975bull993 1953bull
s Oreager William P and Joel D Justin Hydroelectrichandbook 2d ed New York Wiley 19$0 1151 Pbull
6 Daily Jamea w Hydraulic machinery Int Hunter Rouses Engineering hydraulics Hew York Wiley 19$0 p 8$8bull99
Daughertybull Robert L Bydraulie turbines ew Yorkbull7middot MoGrav-Hlll 1920 281 Pbull
8 Daugherty Robert L Inveat1gat1on of tne performance ot a reaction turbine ~anaactiona or the American Society ot Civil Engineers 7811270bull1304 1915
9 Davie L M Model and prototype testa Int Trend in hydraulle turbine practice symposium lranaactions ot the American Society ot Civil Engineers 1o63S3middot368 1941
lfJ Doland James J Hydro power engineering Hew Yorkbull Ronald 1954 209 Pbull
11 Gandy Theodore s and Elmer c Schacht Direct curshyrent motor and generator troubles operation and repair New York McGraw-Bill 1911 293 Pbull
12 Gibaon Arnold H Hydraulics and ita applications5th ed London Constable 1952 813 Pbull
58
13 Button s P Component loases in Kaplan turbinebull and The prediction of efficiency from model tests Probull coedings of the Institution or Mechanical Engineers168743-762 1954
14 Knapp R T~ Oavit t1on mechanics and its relation to the d sign or hydraulic equip ent Proceedings or tne Institution ot Mechanical Engineers 166150bull16) 1952
15 Langsdorf Alexander s Principles of direct curHnt mach1nee 5th ed New York r~cGrawbullH1ll 1940 746 Pbull
16 Lsrner Chester w Characteristica of modern hydraubull lie turbines Trans e~ions of the ~~erican Society ot Civil Engineers 66306-386 1910
17 Linsley Ray K Jr and Jobulleph B Franzin1 Eleshyments of hydraulic enginebullring New York McGrawshyBill 19$5 $82 Pbull
18 Mead Daniel w Hydraulic machinery llev York McGraw-Hill 1933 396 Pbull
19 ead Daniel w Water power engineering New York McGrawbullRill 191S 843 Pbull
20 Mockmore Charles A Part gate operation at water turbines Corvallis Oregon State College Department ot Civil Engineering 1933 11 numb leaves (Unpubshylshed typescript)
21 Mockmore Oharles A Flow characteristics in elbow dratt tubes Transactions of the Amez-ican Society ot Civil Engineers 103402middot464bull 1938
22 Moody L F Hydraulic machinery In c v Davis Handbook ot applied hydraulics New York McGrawshyHlll 1942 1082 Pbull
2) Ptau At-nold Hydrbullulie turbine handbook ld ed Milwaukee AllisbullOhalmers ManufactUIing Company 1948 70 Pbull
RheingalUI w J Recent developments in Francis turshybines Mechanical Engineering 74189-196 1952
25 Russell George E Hydraulica 5th ed New York Henry Holt 1942 466 Pbull
26 Safford A and E P- Hamilton American mixed tlow turbine and ita setting Tranampactions or the Amerieal Society of Civil Engineers 851237bull1)56 1922
27 bull Spannhake W1lhe1Dh Problems or modern pump and tur b1ne design Transactions of the American Society of Mechanical Engineers 56e22$-248 1934bull
28 Sutherlandraquo R A Better ethod or representing and middot tudying water turbine performance ~ansaetions ot thmiddote American Society of Mechanical Engineers 68t675bull 686 1946
29 Teats ot five models or draft tubes tor turbines Engineering News-Record Pbull 182-184 Aug 2 1923
30 White w M American hydztaulic turbines Mechanical Engineering S2t390bull39S 1930bull
31 White w M lhe hydraucGne rega1ner1 its developmentand appl1eat1ons 1n hydroelectric plants Meohanlobulll Engineering 43t37Sbull380 1921 middot
32 Winter I A Economic principlebull in designbull Int Trend in hydraulic urbin practice bull a ampoeiumTranaaot1ona ot the American Society ot Civil Engineerslo6332bull3S2 1941
33 Wiel1cenua G F Fluid mechan1ca or turbo-machineryNev York McGraw-Hill 1947 613 Pbull
APPENDICES
c
Appendix A
NOATIOB
A Angle between the absolute velocity vector and the tangent to the rwmer Subscripts 1 and 2 refel to entrance and exit ot the runner blade
B Angle between the relative 1elooity vector and the tangent to the rwmer Subscripta 1 and 2 refer to entrance and ezit or the runner blade
Angle between the tangent to the runner blade tip and the tangent to the runnel- Subscripts 1 and 2 reter to entrance and exit of the rt1rmer bladebull
Blade angle-gate opening conetant defined by equation (1)
e 09erall efficiency
g Gravitational acceleration assumed constant at 322 teet per second per second bull
H Turbine head detined by equation ($)
m Exit loss coeft1e1ent
Turbine speed expressed in revolutions per minute
Turbine speed under a constant head of 81 teet
specitic apeed of the turbine under a constant head ot 81 teet
p Power output in horsepower ot the tvbine
Power output of the turbine Ulder a constant head ot Sl teet
Pl- Pressure head at entrance to the tUlb1new
l1 Peripheral velocity ot the runneP Subacr1pta 1 and 2 refer to entrance and exit ot the JUnllampr blade
62
v Relative velocity reaulting trom the combination ot the absolute water velocity V and the runner periphshyeral velocity u Subscripts 1 and 2 refer to entrance and exit ot the runner blade
v] Relative velocity vector necessary to produce a tanbull gential entry into the runner blades
V Absolute water velocity Subscripts l and 2 refer to entrano and exit ot the runner blade
v2 Velocity head Subscripts 1 and 4 reter to the ~8 entrance to the turbine and the tail~ace wate~
w Unit weight ot water assumed constant at 624 pounda per cubic toot
V Weight rate ot flow in pounds per aeooncl
XX Velocity component ot ahook See Figule 2
Z Elevation head Subscripts 1 and 4 reter to entrance to the turbine and the taibace water surfacebull
Appendix B ORIGINAL DATA-Run
lfwnber
0-4-1 0-4-2 0-4-3 o-4-4 o-4-S o-4-6 0-4-7 0-4-8 0-4-9o-4-lo o-4-11 o-4-12 0-4-13
o-6-1 o-6-2 06-3 o-6-4o-6middotS o-6-6 o-6-7 o-6-8 0-6-9 o--6-lo o-6-11
Speed
rmiddot2middotbullmiddot(1)
336 38$ 451 S$9 620 669 6lt)$ 120 787 860 932
102imiddot109 bull
352 355 443middot 543middot 620 654AJs32
911 1001 1111
~essure Head rt (2)
410 410 416 426 431 43-7 439 44-9 452 467 482 soo $1 bull $
350 351 35middot7 )66 37-9 37-9 392 41 bull 3 43middot3 460 489
Elevation Bead
fjj $7 $7 $7 $7 $7 $7 51 57 5-15858 $8 58 56 56 $6565656 51 575As5a
Velocit Head
flj 07 07 07 06 06 06 06 os 05 os0404 03
09 09 oa o8 o8 os 07 07 06 o~o
Total Head rt ($)
47middot4 4A44 o 489 49-4 soo $02 $11 $14 $29 5imiddot45 2 576
41 bull $ 416 421 430 44middot3 44middot3 456 47-7 496 523551
Plow
lbtjec
326 324middot317 311 306 30029middot28 middotmiddot middot 386 275middot260 240 218
359 36~35 bull 349 345middot 339 330 318 300 273 240
Line Potential
vyqjbull 1060 1220 ~-0o 1920 2150 2000 2$60 2000 1940 18)015io11 o
1000 1100 139bull5 1760 1925 16$0 1620 1610 1540 1330 870
Line Current
amlscs 960 900 830 740 730655 70bull 0 530 660 600 5imiddot54 6 )60
982 930 860 780 ~3-545
79-5 74-5 670 560 370
P
Appendix B ORIGINAL DATA (Continued)
Run Number
Speed
Pbulltmiddotbullmiddot )
leasure Head ft(2
Elevation Head tt(J)
Velocity He-dfmiddotj
Total Bead tt($
Flow
lbstsec( )
Line Potential vo~ta( )
Line Current
amjs (sect
0bulllt)-1 0-9-2
3ll6 398
28o ~~1
$6 56
1o 10
346 347
390 365
1ooo 1190
aao 835
0-9-3 0-9-4 o-9-S
472 565 632
292 305 312
$6 s6 56
10 o9 o9
)$8 J7~o 37~7
381376 37o
1)6614oo 141o
820 ass ass o-9-6 0-9-7 0-9-8 o-9-9 0middot9-10
680 120 762 844 920
)24337346 366 390
56 $6 56 57 $7
09 os o8 oa 07
)89401 410 431454
367~ 357348 34o 322
1400 1J6o l36o 1310 1170
843 820 7957So 67~0
0-9-ll 0-912
1001 1100
41 bull 7 45-3
s 7 6~0
06 os 480 $18
299 268
980 65$
560 36~5
1-4-1 1-4-21-4-l1-4shy1-4-5 1-4-6 l-4-7 1 4-8 1-4-9 1-4-10 1middot4-ll 1-4bull12
354middot452 562 62q 674shy102 752 760- 863 932
1022 1100-
)82389 4014oa 416 41--7 423 428 44-2 45-7 486 49-2
51S757 51 5-7 5middot15zs sa $8 58 59
07 07 06 06 06 06 06 os o bull o 04 o J
446 45-)46middot4 471 ti7-9480 q86 491505 $19 548 55-4
)28 320 311 306 300 295 291 286 269 2582iimiddot21 bull
1080 14Lo 1550 153-5 1470 141-0 1385 1310 1310 1230 1120 855
970855 875 91-0 94~0 975 966 995 860 77-S 610 4fo
0 ~
Appendix B ORIGINAL DATA (Contirmed)-Run Speed Pressure Elevation Velocity Total Flow Line Line
Number Head Head Head had Potential Current rtjjmbull t~ bttec vyfs am~a12) ( ) ti fli 8
1-6-l $6 33$ $6 0bull9 400 364 1100 93 0 1-6-2 41 34laquo2 $6 oa 406 JS7middot iios a5s l-6-3 500 3~0 5bull6 os 356 1 1 o aos 41middot~1-6~4 35bull4 5-6 oa 41middot 352 16~0 82 0 5~1-6-5 5 bull 36_2 Sbull6 08 42bull6 349middot 161 ~ 0 86~0 1-6-6 622 366 $6 oe 43bull0 345middot 158 0 88~$ 16-A 649bull 37bull1 56 os 43-S 342middot 1570 895 1~- 386 57 07 46-0 192 ) 125A44 333middot 1-6-9 3) 404 5middot1 07 468 317 1620 675 1610 911 42-4 5-7 o6 48-7 298 168 0 61 0 1-6-11 999 451 56 os Sl ll 276 ~2-0 530 1-612 1115 485 58 04 54middot7 238 90 )3 0
1middot9-l 355 279 56 10 )45 385 1040 870 1-9-2 399 28J $6 10 )49 38$ 1140 86 5 l-9-3 ~ ao 291 56 ~0 35middot1 J8J_ JJ6o 815 1bull9-4 579 303 56 09 )68 375middot J4JO 830 l-9bullS 40- 313 )6 09 31middot8 370- 1460 82~0 1-9bull6 679 2) 56 09 3 bull8 364middot 1670 710 l-9-7 682 319 56 o9 384 ) 62 1460 79 5 l-9-8 724 33middot5 56 o8 399 3$6 bull 1480 76 -5 1-9-9 762 34middot3 $6 0 bull 8 407 )48 14910 13middotS 1-9-10 833middot )60 5middot7 os 42$ 339 144$ 686 1-9-ll 926 39middot1 5-7 07 455 318 1290 600 1-9-12 1000 41middot3 0-6 476 298 1115 510$ ~ 1middot9-13 1105 452 s o4 $14 2$6 710 )10
~
Appendix Bt ORIGDIAL J (Continued)
Run Speed Pressure Elevation Velocity Total Plow Line Line Number Head ltead Head jlamp$d P()ten~ibulll Current
r~~~m ft ft lbs~seo voltattj rgj twimiddot t 1 t2gt lt3 ou t ( rt
2-9-1 384 289 S 6 10 35 5 1400 1170 810 2-9-2 443middot 29$ $6 ltimiddot9 360 379middot 11(0 87$ 2-9-J 536 30bull 3 sc 09 )68 374middot 1)40 84 bull) 2-9-4 571 306 $6 09 3~1 372 120bull 0 955 2-9-5 623 316 S6 09 J l )6S UJSo 77$ 2bull9-6 669 327 S6 09 )92 )61 1240 905 2-9bull7 712 )39 56 os 40-3 351 12(0 86 bull0 2-9-8 ~5$~ J48 56 oa 412 348 1290 81 bull ) 2-9-9 04 )63 56 oa 42-7 339 12ltJO 76$ 2middotmiddot9-10 8$2 376 5middot1 07 440 33~- ~ o 710 2-9-11 955 394 5-1 o6 457 300 1100 506 2middot9-12 1000 421 $7 06 48middoti 295 1020 $18 2-9bull13 110~ 463 56 05 $2 267 620 3~0
oshy0
Appendix Gt CALCULATED DAgA
Turbine Run Generator Generator Turbine Turbine Efficiency Turbine Turbine Specit1c
Number OutputKWlt21
Loa~Jes KWlol
Outut K bull (H)
Input RP 12)
middot Percentlt13gt
Speed r~Jmiddot(
0ltput HP ~1
Speed r-m
( 6) middot
o-4-1 0middot4-2 0-4-3 0-4-4 0-4-5 0-4-6 O-qmiddot7o-4-8o-4-9 0-4bull10 0-4-11 o-4-12
1018 1o9a 1220 1)62J40214oa1J4oo 1357 1320 1164 997 718
046 o59 071 092 096 1071oo 134 104 100 109 107
14261sso 17)01948 2008 20322011 1999 19 09 1708 14-84 11o6
281279 27-7 276 215 273271 268 268 26h 258 24-5
soa 555 62$ 705 7)1145 742 74-6714645 51s 45-1
440 sos 585 720 195 sso sao 9$$ 985
1065 1135middot 1230
318 357 319 416 422 419412 39middot9 378 324 260 191
102 12bull4 148 191 21bull 3 22o 233 249 24924middot9 238 221
0-4middot13 418 104 699 228 306 1300 117 18)
o-6-1 982 045 1376 271 $08 496 376 124 o-6-2 o-6-3 G-6-4o-6-5 0-6-6
1023 1200 13 73 J415 139h
051 0middot66 oaa ()bull 96 088
14-39 1696 1958 2026 1986
276 27middot4 273 278 274
$20 61 8 717 7)0726
q95615745 8)5685
390 ll5middot3 sos soo 490
127 170 218 243 2$$
o-6-7 o-6-8 o-6-9o-6-lo
1288 1199 1032 7-45
o9o 094 09$ 096
1846 1733 1511 1128
274 276 271 260
67S 629559 43middot4
980 1085 1165 1245shy
436 )83316 21bull 7
266 276 270 239
0-6-11 322 1oo 566 2141 2JS 1350 101 177 0 --4
Appendix C CALCULATED DAlA ( Continued)-Run
Number Generator Generator
Out2ut Losaes xw LW- 12gt (lO)
Turbine Out2ut
ltPlJ
Turbine Inat lfP Jig)
Etpound1e1ency
PireentDl
Turbine Sed x-~m( 1
Turbine OutEut RPJl)
Turbine Specific
SeeedrIbullntbull
( 6)
o-9middot1 0-9-2 0-9-3 o-lt)-4 09-$ 0bull9-6 0-9-7 0-9-8 0-9-9 0-9-10 o-9-11 0-9-12
aao 994
111$ 1197 1206 1180 11)21081 982 784 5-49 2)9
0middot45oss o6$ 070 07$ 0-77 (l77 or~ o s06o 8 096
123~ 1402 1$80 1698 17bulllS 168$ 16bull18 ~middot5430 1151 a~J4 9
24middotgt24middot3248 25~25 260 260 259 267 266 26middot1 2S2
sos 577 63-7 671 676 650 621 60036J4
327 178
$) 610AlO 3$
92S 980
102$ 1070 1157middot 1230 1300 137Smiddot
44middot4 soo 523 ssomiddot 540so6 46-5 432 368 274 18~8
J46 176 21-1 255 2802s_A 28 289 288 265 231 168
1-4-1 1-4middot2 1-4-3 1-4-4 1-4-5 1-4-6 1-4-7 1-J-8 1-4~9 1-4-10 1-4-11 1-4-12
10bull48 1231 13-S6 1397 1)821375 1))8 1303 1127 953 683) 51
048 067 o7A07 0 bull79 oa1 oss o bullao osa 0lt)0 096 099
J468 1740 1921 1978 1958 19$1 1911 lSSi162 1)98 1045
603
266 264 262 262 261 2512$7 2$6 24middot7 24-3 233 217
551 660 13middot3155 75-6 7~-97 middot4 72$ 67 51middotJ 44middot9 21middot1
475 605 A4220
875middot 910 970_
1000 1090bull 1166 1243 1330
5816
44middot444middot5 430 427 412 392 329 273 188 l0-7
117 101 204 22$ 2)7245 2562sa 257251 222 179
a-C))
Appendix Ct CALCULATED -DATA ( Ocntinued)
1-6middot1 1023 o$2 14-41 26S 505 41~6 26~
54middot5 13middot3l-6-2 1201 067 1boo 625 47-9 17shy~middot41-6bull3 1296 oA9 1 middot43 26 9 700 so5 20bull 4 l-6-4 l3j5 o 0 19~09 268 71bull3 A5o 514 222 1-6-5 1) 5 o81 19(gt4 271 725 51-5 238 l-66 1398 081 198) 27-0 736 8 S13 252~-middot l-6j 1405 083 199i 211 733 885 $middot06 2$9 l-6 13middot9~ 103 2amp 0 279 71 8 985~ 467 ~-69 1228 1 bull 02 17-SS 270 661 109$ 407 ~3~ l-6bull10 1025 100 lSll 26i 573 1175middot 27~S32middot~l-ampu 153 1-00 llft3 26 444 1270 22 24bull8 1bull6-12 294 100 52a 231 22 3 1360 95 172
1-9bull1 904 048 1275 2J4Z $28 S4$ 459 1$2 1-92 98$ oss 13-92 24middot4 57-0 6JO 49bull1 176 1-9middot3 1110 066 1$76 24middot9 63middot4 I2o 536 21-7 l--9-4 1187 072 1685 251 66$ 5 $$ bull 0 261 1middot9-5 llltJ7 1710 25middot4 67-3 93$ 536 28~20-671middot9-6 1186 o 8 1708 25-7 67) 980 $15 2691-9- 1161 oBo 1660 2$middot3 6$6 990 508 29-1 l~- ll-32 oB) 16sect0 2$8 632 1030 471 291 1-9bull9 109$ oa5 2$7 614 1075 29S~middot 0 4imiddot41-9-10 9~91 oas 262 S$1 1150~ 3 o 292 1-9-11 o9o u57 12JiO 21gt 26-77middot74
-45 26sect ~middot91-912 $69 091 sas 25 middot3 1)0$ 196 2J-8 1-9-1) 220 098 426 2)9 178 1390middot 84 16 6
0 0
Appendx C CALCULATED DATA (Continued)
Turbine Run Generator Generator lurbine Turbine Eft1e1eney Turbine lurbine Spee1f1c
Number Output Losses Outit Input Speed Output SPed middot k_-V KW R _ H_bull_P Percent r Thm HP rpm_ (9) tlo) 11) middot (12 _) (lJI ( ) (1$ (14)
2-9-1 9--46 055 1)62 258 528 580 164 2-9-2 1024 056 248 58 4 665 4 9 191iimiddot48 4~middot0 2-9-3 1132 067 05 2$0 641 795 52q 237 2-9-4 1148 065 1027 2$1 -~8 845 525 252 2-9-5 11 77 oso 16-83 253 6 910~ 522 270 2-9 6 1122 071 1600 251 622 960 47-5 2722-9-A 1092 015 1562 257 608 1010 445 2z12bull9- 1052 079 1514 261 580 1060 41middot7 2 2 2middot9-9 986 o82 ]429 26) 542 1105 372 277 2-9-10 915 086 1340 268 500 1160 334 27-6 2-9-11 638 087 972 254 )81 1270~ 229 250 2-9-12 )28 090 828 259 )19 1295 179 226 2-9-13 192 094 383 2$ 6 150 1370 7 3 152
-3 0