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7/30/2019 Chapter 5 KTTK
1/26
Presented By
Harry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
Gii thiu cc loi tn tht
Ni dung chnh
Tm hiu th nghim Reynolds
Tnh ton tn tht dc ng
Cht lng chy tng
Cht lng chy ri
Tnh ton tn tht cc b
K thut thu kh
http://www.presentationpro.com/power_designs.aspxhttp://www.presentationpro.com/power_designs.aspxhttp://www.presentationpro.com/power_designs.aspxhttp://www.presentationpro.com/power_designs.aspx7/30/2019 Chapter 5 KTTK
2/26
Presented By
Harry Mills /PRESENTATIONPRO
K thut thu kh
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.1 TN THT NNG LNG DNG CHY
5.1.1 Nguyn nhngy tn tht
Chtlng c
tnh nht
C s ma sttrong khi
chuyn ng
Binthnh
nhit nng
Nhit ivo mi
trng
7/30/2019 Chapter 5 KTTK
3/26
Presented By
Harry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.1 TN THT NNG LNG DNG CHY
5.1.1 Nguyn nhngy tn tht
Bm cp nng lng cho
cht lng chuyn ng K thut thu kh
7/30/2019 Chapter 5 KTTK
4/26
Presented By
Harry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.1 TN THT NNG LNG DNG CHY
Hai loi tn tht chnh
K thut thu kh
KhoTn tht ccb
Tn tht dc -ng
7/30/2019 Chapter 5 KTTK
5/26
Presented By
Harry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.1 TN THT NNG LNG DNG CHY
5.1.2 Tn tht dc ng
K hiu
dn v mCng thc tnh tng qut
Sinh ra trn ton b
chiu di dng chy.L tn tht xy radc theo ng dichuyn ca dng
chy do s ma stca cht lng vithnh rntip xcg2
v
R4
l.h
2
d
K thut thu kh
7/30/2019 Chapter 5 KTTK
6/26
Presented By
Harry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.1 TN THT NNG LNG DNG CHY
5.1.2 Tn tht dc ng
Trong : hssccn ma st,phthuc votrng thi chyca dng chy. l (m)chiu di on tnh tntht. R (m) bn knh thulc v (m/s) vntcon dng chy ng trn: d = 4R
K thut thu kh
g2
v
R4
l.h
2
d
7/30/2019 Chapter 5 KTTK
7/26
Presented By
Harry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.1 TN THT NNG LNG DNG CHY
5.1.3 Tn tht cc b
K hiu
cn v mCng thc tnh tng qut
Sinh ra ti nhngni dng chybinitngt. Thdtnthttich cong
cang, tn tht tini thu hp, ti cht van...g2
v.h2
Cc
K thut thu kh
7/30/2019 Chapter 5 KTTK
8/26
Presented By
Harry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.1 TN THT NNG LNG DNG CHY
5.1.3 Tn tht cc b
c l hs tn thtccb,phthuc vo tngv trxy ra tntht. v (m/s) vn tcv tr
xy ra tntht.
Trong :
K thut thu kh
g2
v.h
2
Cc
7/30/2019 Chapter 5 KTTK
9/26
Presented By
Harry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.1 TN THT NNG LNG DNG CHY
5.1.3 Tn tht cc b
Tn tht nng lng ca ton b
on dng ang xt
m
i
di
n
i
Ciw hhh11
21
m
1i
2
i
i
ii
n
1i
2
iCi21w
g2
v
d
l
g2
vh
K thut thu kh
n: s v tr tn tht cc b
m: s on ng tnh ton tn
tht dc ng
7/30/2019 Chapter 5 KTTK
10/26
Presented By
Harry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.2 HAI CH CHY TH NGHIM REYNOLDS
5.2.1 Cc ch chy ca dng chy
Chy tng
cc phn tcht lng
chuyn ng
theo nhngtng lp khng
xo ln vo
nhau
Chy ri
cc phn t chtlng chuyn
ng v trt t,hn lon
K thut thu khLink th nghim
http://localhost/var/www/apps/conversion/releases/20121107221618/tmp/phim/dns-large.mpeghttp://localhost/var/www/apps/conversion/releases/20121107221618/tmp/phim/dns-large.mpeghttp://localhost/var/www/apps/conversion/releases/20121107221618/tmp/phim/dns-large.mpeg7/30/2019 Chapter 5 KTTK
11/26
Presented By
Harry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.2 HAI CH CHY TH NGHIM REYNOLDS
5.2.2 Th nghim Reynolds
Thay i vn tc dng chy trong ng
Thay i nhit nc t 4oC n 44oC
Th nghim nhiu ng c ng knh khc nhau
K thut thu kh
Kt lun: Dng chy thay i trng thi khi thay i cc yu t trn
http://localhost/var/www/apps/conversion/releases/20121107221618/tmp/phim/dns-large.mpeghttp://localhost/var/www/apps/conversion/releases/20121107221618/tmp/phim/movie_streak_cyl.mpeghttp://localhost/var/www/apps/conversion/releases/20121107221618/tmp/phim/movie_iso_obst.mpeg7/30/2019 Chapter 5 KTTK
12/26
Presented By
Harry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.2 HAI CH CHY TH NGHIM REYNOLDS
5.2.2 Th nghim Reynolds
Trng thi
chy phthuc vo
Vn tcdng chy
Kch
thc ngLoi cht
lng
K
thut thu
kh
7/30/2019 Chapter 5 KTTK
13/26
Presented By
Harry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.2 HAI CH CHY TH NGHIM REYNOLDS
5.2.3 Tiu chun phn bit hai ch chy
K
thut thu
kh
Tiu chunphn bit
ch chy
Dng t hp khng th nguyn (s Reynolds)
d.vRe
Lu : cng thc trn dng tnh cho ngtrn ng knh d.
7/30/2019 Chapter 5 KTTK
14/26
Presented By
Harry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.2 HAI CH CHY TH NGHIM REYNOLDS
5.2.3 Tiu chun phn bit hai ch c chy
K
thut thu
kh
Mt ct bt k
Trong : (m2/s): H s nht ng hc
d (m) : ng knh ngv (m/s) : Lu tc trung bnh mt ctR (m) : Bn knh thu lc mt ct
RR .vRe
7/30/2019 Chapter 5 KTTK
15/26
Presented By
Harry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.2 HAI CH CHY TH NGHIM REYNOLDS
5.2.3 Tiu chun phn bit hai ch c chy
K thut thu kh
7/30/2019 Chapter 5 KTTK
16/26
Presented By
Harry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.2 HAI CH CHY TH NGHIM REYNOLDS
5.2.3 Tiu chun phn bit hai ch c chy
K
thut thu
kh
Vd:Xc nh trng thi chycadu trong ngnung c ng knh d=150mm; vn tc v=0,3m/s; nhtng=0,28 st (1 st = 1 cm2/s)?
Ktqu: Re=1607 < 2320
Kt lun:Du chy tng trong ng
7/30/2019 Chapter 5 KTTK
17/26
Presented By
Harry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.3 TNH TON TN THT DC NG
K
thut thu
kh
Xc nh trng thi chy ca dng chy
Xc nh h s sc cn ma st
Chy tng:Re
64
Chy ri: Ref
7/30/2019 Chapter 5 KTTK
18/26
Presented ByHarry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.3 TNH TON TN THT DC NG
K
thut thu
kh
Tn Cngthc
2
8
C
g
Chezy Maning
Blart
Canacp
Antsun
Nicurats
4 Re
3164,0
25,1Relg8,11
25,0
Re
10046,11,0
d
2
14,1lg2
1
d
Gii thiu mt s cng thc tnh khi dng chy ri
7/30/2019 Chapter 5 KTTK
19/26
Presented ByHarry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.4 TNH TON TN THT CC B
K
thu
t thu
kh
g
v
g
vvhc
21
2
21
2
2
12
21
V1; 1
V2; 2
1
1
2
22
2
11
mr
Mt s v tr xy ta tn tht cc b thng gp
Tn tht do t ngt m rng
Dng chy t ng i vo b cha rt rng cr=1
7/30/2019 Chapter 5 KTTK
20/26
Presented ByHarry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.3 TNH TON TN THT CC B
K thut thu kh
Mt s v tr xy ta tn tht cc b thng gp
Tn tht do t ngt thu hp
Dng chy t b cha rt rngi vo ng cv=0,5
1
215,0
tc
1 2
7/30/2019 Chapter 5 KTTK
21/26
Presented ByHarry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.3 TNH TON TN THT CC B
K thut thu kh
Mt s v tr xy ta tn tht cc b thng gp
Tn tht un
- Nu gc cong = 90o
ca ng trn bn knh ro,bn knh cong l R ta c:
5,3o
CR
r85,113,0
- Nu gc cong 90o
ta nhn Cvi o90
R
ro
7/30/2019 Chapter 5 KTTK
22/26
Presented ByHarry Mills /PRESENTATIONPRO
Chng : CHUYN NG MT CHIU CACHT LNG KHNG NN
5.3 TNH TON TN THT CC B
K thut thu kh
Mt s v tr xy ta tn tht cc b thng gp
Tn tht qua van
H s Cph thuc vo gc m cho bi bng sau y:
o 5 10 20 30 40 50 60 70 80
C 0,05 0,29 1,56 5,47 17,3 52,6 206 486
7/30/2019 Chapter 5 KTTK
23/26
Presented ByHarry Mills /PRESENTATIONPRO
Bi tp v d:
K thut thu kh
H1
H2
7/30/2019 Chapter 5 KTTK
24/26
Presented ByHarry Mills /PRESENTATIONPRO
Bi tp v d:
K thut thu kh
ngc ngknh ngthnhtd1 =200mm; l1=20m;ngthhai d2=100mm; l2=35m.
H1 = 15m; H2 =5m
Hstnthttica vo: cv = 0,5; ti van v=1,56; cara cr=1; un cong tibm v qua bmu=0,9.Hscn ma stng1 1=0,026; 2=0,02;Cht lng l nc c nht ng =0,0101 (cm2/s);
r=998,23kg/m3
Mtthong 2 btip xc vi khtri.Ctp bm cung cp cho hthngl Hb=5m.Lyhshiuchnhngnng=2.
7/30/2019 Chapter 5 KTTK
25/26
Presented ByHarry Mills /PRESENTATIONPRO
Bi tp v d:
K thut thu kh
Tm:
1/ Lu lng Q chy trong ng? V kim tra trng thi chy
ca dng chy trong 2 ng? (chung c nhm tho lun)2/ Tm tn tht ti ca vo? (T 1)3/ Tm tng tn tht dc ng trn ng 1? (T 2)4/ Tm tn tht un v qua bm? (T 3)5/ Tm tng tn tht dc ng trn ng 2? (T 4)6/ Tm tn tht qua van? (T 5)7/ Tm tn tht ti ca ra? (T 6)
7/30/2019 Chapter 5 KTTK
26/26
Presented ByHarry Mills /PRESENTATIONPRO
THO LUN TUN TH 11
CH : TNH TON TN THT
C nhm thit lp bi ton
Nhm khc gii quyt
Nhm thit lp gii quyt bi ton
K thut thu kh
a ra bi ton v tr li trc 10pht
a ra bi ton v tr li trc 15 pht
a ra bi ton v tr li trc 20pht
a ra bi ton v tr li sau 25 pht
100%
80%
40%
20%