FluidMachines_labManual_2008_revised

8/7/2019 FluidMachines_labManual_2008_revised

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Laboratory Manual

FLUID MECHANICS ANDMACHINES

LABORATORY

DEPARTMENT OF MECHANICALENGINEERING

Prepared by:Dr. DEBOJYOTI MITRA


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LIST OF EXPERIMENTS

SERIAL

NO.

NAME OF EXPERIMENT HOURS

1 Calibration of Venturimeter 22 Calibration of Orificemeter 23 Calibration of Rotameter 24 Calibration of Rectangular and V-Notches 25 Reynolds experiment: Laminar and Turbulent flow 26 Determination of friction factor of pipes 27 Determination of loss coefficients of pipe fittings 28 a) Determination of jet impact on plane surface 2

b) Determination of jet impact on hemispherical surface 29 Performance characteristics of variable speed centrifugal

pump

2

10 Performance characteristics of Francis turbine 211 Performance test of a Pelton wheel Turbine 212 a) Performance test of reciprocating pump 2

b) Performance test of gear pump 2

Experiment No. 8 (A)

TITLE

A) DETERMINATION OF JET IMPACT ON PLANE SURFACE

OBJECTIVES


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To study the force exerted by a liquid jet impact on a plane surface.

INTRODUCTION

A plate, placed in the path of a liquid jet, experiences a force on it. This force can becalculated from the impulse-momentum equation, which is based on Newtons SecondLaw of Motion: The algebraic sum of external forces applied to control volume of fluidin any direction is equal to the rate of change of momentum in that direction.

THEORY

Consider a water jet, moving vertically with a velocity V, impacts on a flat plane whichcan move freely in vertical direction. This force, according to Newtons Second Law ofMotion, must be equal to the rate of change of momentum of the jet flow in the samedirection. An equal amount of force will then be required to bring back the plate in its

original position.Therefore,

Fx = the force exerted by the jet in the direction of the jet= force required to bring back the plate in its original position= rate of change of momentum in the direction of force

=time

momentumFinalmomentumInitial

=time

velocityfinalxmassvelocityinitialxmass

= ( )velocityfinalvelocityinitialtimemass

= ( )0VAV= 2AV

DESCRIPTION OF EXPERIMENTAL SET-UP

The set-up consists of a sump tank with centrifugal pump to circulate water. A chamberwith two side glass is provided for visualization of impact of jet on vanes. Water fromsump tank flows through a nozzle and strikes vertically the vane (here, a flat one)positioned above the nozzle. Arrangement is made for the movement of the plate of the

vane under the action of the jet and also because of the weight placed on the loading pan.Measuring tank and stop watch is provided for flow measurement.

UTILITIES REQUIRED

1. Electric supply: single phase, 220 V AC, 50 Hz, 5 15 Amp socket with earthconnection

2. Water supply (initial fill)


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3. Drain4. Bench area: 1.5 m x 0.75 m

EXPERIMENTAL PROCEDURE

1. Close all the valves provided2. Fill sump tank th with water and ensure that no foreign particles are there3. Fix flat vane4. Ensure that all ON/OFF switches given on the panel are at OFF position5. Open bypass valve6. Switch ON the pump7. Put weight on the pan8. Operate bypass valve and flow control valve to regulate the flow of water

through channel9. Now control the flow of water so that the applied weight on the top is counter-

balanced by the impact of jet

10. Measure flow rate using measuring tank and stop watch11. Repeat the experiment for different weights12. Switch off the pump when the experiment is over13. Switch off power supply to panel14. Drain water from all tanks with the help of drain valves

OBSERVATION TABLE

S. No. WA, kg R 1, cm R 2, cm t, sec

CALCULATIONS

The following formulae may be used for calculation of results :

2

4da

= , m2

100

21RR

R

= , m


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t

RxAQ = , m3/sec

A

QV = , m/sec

2VxaxFx = , N

W = WD+R+ WF + WA, kg

Fth = W x g, N

100% xF

FFError

x

thx

=

Where,

A = Area of measuring tank = 0.077 m2

a = Cross sectional area of the nozzle, m2

d = Diameter of Nozzle = 0.01 mFx = Rate of change of momentum (Actual Force), NFth = Theoretical Force, NQ = Actual discharge, m3/secR = Rise of water level in measuring tank, mR1 = Final height of water in measuring tank after time t, mR2 = Initial height of water in measuring tank, mt = Time for R, secV = Velocity of jet, m/sW = Total weight, kgWD+R = Weight of aluminium disc with rod = 0.538 kgWF = Weight of flat plate vane = 0.227 kgWA = Weight applied on disc, kg = Density of water = 1000 kg/m3

g = Acceleration due to gravity, m/sec2

RESULTS

S. No. A R Q V Fx W Fth %Error


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PRECAUTION & MAINTENANCE INSTRUCTIONS

1. Never run the apparatus if power supply is less than 180 Volts and 230 Volts2. Never switch ON main power supply before ensuring that ON/OFF switch

given on the panel is at OFF position3. Always use clean water4. Never fully close the delivery valve and bypass valve at a time5. Always keep apparatus free from dust

TROUBLESHOOTING

1. If pump gets jammed, open the back cover of pump and rotate the shaftmanually

2. If pump gets heated up, switch OFF the main power for 15 minutes and avoidclosing the flow control valve and bypass valve at a time

REFERENCES

1. Dr. R. K. Bansal, Fluid Mechanics & Hydraulic Machines, LaxmiPublications (P) Ltd, New Delhi.

REVIEW QUESTIONS:

1. Draw a neat labeled sketch of the experimental set-up.

2. Find the force exerted by a jet of water of diameter 75 mm on a stationary flatplate, when the jet strikes the plate normally with velocity of 20 m/s.

3. Plot a curve between the %Error and the flow rate Q and find out whether there isany dependence between them or not.

Experiment No. 8 (B)

TITLE

B) DETERMINATION OF JET IMPACT ON HEMISPHERICAL SURFACE

OBJECTIVES

To study the force exerted by a liquid jet impact on a hemispherical surface.


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INTRODUCTION

A plate, placed in the path of a liquid jet, experiences a force on it. This force can becalculated from the impulse-momentum equation, which is based on Newtons SecondLaw of Motion: The algebraic sum of external forces applied to control volume of fluid

in any direction is equal to the rate of change of momentum in that direction.THEORY

Consider a water jet, moving vertically with a velocity V, impacts on a hemisphericalplane which can move freely in vertical direction. This force, according to NewtonsSecond Law of Motion, must be equal to the rate of change of momentum of the jet flowin the same direction. An equal amount of force will then be required to bring back theplate in its original position.

Therefore,

Fx = the force exerted by the jet in the direction of the jet= force required to bring back the plate in its original position= rate of change of momentum in the direction of force

=time

momentumFinalmomentumInitial

=time

velocityfinalxmassvelocityinitialxmass

= ( )velocityfinalvelocityinitialtime

mass

= ( )( )VVAV

=2

2 AV

DESCRIPTION OF EXPERIMENTAL SET-UP

The set-up consists of a sump tank with centrifugal pump to circulate water. A chamberwith two side glass is provided for visualization of impact of jet on vanes. Water fromsump tank flows through a nozzle and strikes vertically the vane (here, a hemisphericalone) positioned above the nozzle. Arrangement is made for the movement of the plate ofthe vane under the action of the jet and also because of the weight placed on the loadingpan. Measuring tank and stop watch is provided for flow measurement.

UTILITIES REQUIRED

1. Electric supply: single phase, 220 V AC, 50 Hz, 5 15 Amp socket with earthconnection

2. Water supply (initial fill)3. Drain4. Bench area: 1.5 m x 0.75 m


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1. Close all the valves provided2. Fill sump tank th with water and ensure that no foreign particles are there3. Fix hemispherical vane

4. Ensure that all ON/OFF switches given on the panel are at OFF position5. Open bypass valve6. Switch ON the pump7. Put weight on the pan8. Operate bypass valve and flow control valve to regulate the flow of water through

channel9. Now control the flow of water so that the applied weight on the top is counter-

balanced by the impact of jet10. Measure flow rate using measuring tank and stop watch11. Repeat the experiment for different weights12. Switch off the pump when the experiment is over

13. Switch off power supply to panel14. Drain water from all tanks with the help of drain valves

OBSERVATION TABLE

S. No. WA, kg R 1, cm R 2, cm t, sec

CALCULATIONS

The following formulae may be used for calculation of results:

2

4da

= , m2

100

21RR

R

= , m

t

RxAQ = , m3/sec


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A

QV = , m/sec

22 VxaxxFx = , N

W = WD+R+ WH + WA, kg

Fth = W x g, N

100% xF

FFError

x

thx

=

Where,

A = Area of measuring tank = 0.077 m2

a = Cross sectional area of the nozzle, m2

d = Diameter of Nozzle = 0.01 mFx = Rate of change of momentum (Actual Force), NFth = Theoretical Force, NQ = Actual discharge, m3/secR = Rise of water level in measuring tank, mR1 = Final height of water in measuring tank after time t, mR2 = Initial height of water in measuring tank, mt = Time for R, secV = Velocity of jet, m/sW = Total weight, kgWD+R = Weight of aluminium disc with rod = 0.538 kgWH = Weight of hemispherical vane = 0.227 kgWA = Weight applied on disc, kg = Density of water = 1000 kg/m3

g = Acceleration due to gravity, m/sec2

RESULTS

S. No. A R Q V Fx W Fth %Error


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PRECAUTION & MAINTENANCE INSTRUCTIONS

1. Never run the apparatus if power supply is less than 180 Volts and 230 Volts2. Never switch ON main power supply before ensuring that ON/OFF switch given

on the panel is at OFF position3. Always use clean water4. Never fully close the delivery valve and bypass valve at a time5. Always keep apparatus free from dust

TROUBLESHOOTING

1. If pump gets jammed, open the back cover of pump and rotate the shaft manually2. If pump gets heated up, switch OFF the main power for 15 minutes and avoidclosing the flow control valve and bypass valve at a time

REFERENCES

1. Dr. R. K. Bansal, Fluid Mechanics & Hydraulic Machines, Laxmi Publications(P) Ltd, New Delhi.

REVIEW QUESTIONS:

1. Draw a neat labeled sketch of the experimental set-up.2. Find the force exerted by a jet of water of diameter 75 mm on a stationary

hemispherical plate, when the jet strikes the plate normally with velocity of 20m/s.

3. Plot a curve between the %Error and the flow rate Q and find out whether there isany dependence between them or not.

Experiment No. 9

TITLE

PERFORMANCE CHARACTERSTICS OF VARIABLE SPEED CENTRIFUGAL

PUMP

OBJECTIVE:

a) To Study the Centrifugal pump characteristics and determine:


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- Power input- Shaft output- Discharge- Total head- Pump output

- Overall efficiency- Pump efficiency

b) To plot the following performance characteristics :-

Head Vs DischargePump efficiency Vs Discharge

INTRODUCTION:

The hydraulic machines, which convert the mechanical energy into hydraulic energy, arecalled pumps. The hydraulic energy is in the form of pressure energy. If the mechanicalenergy is converted into pressure energy by means of centrifugal force acting on thefluid, the hydraulic machine is called centrifugal pump.

THEORY:

The centrifugal pump acts as a reversed of an inward radial flow reaction turbine. Thismeans that the flow in centrifugal pumps is in the radial outward directions. Thecentrifugal pump works on the principle of forced vortex flow, which means that when anexternal torque rotates a certain mass of liquid, the rise in the pressure head of therotating liquid takes place. The rise in pressure head at any point of the rotating liquid isproportional to the square of tangential velocity of ( i.e. rise in pressure head = V2 / 2g or2r2 / 2g ) the liquid at that point. Thus, at the outlet of the impeller where radius is more,the rise in pressure head will be more and the liquid will be discharged at the outlet with ahigh-pressure head. Due to this high-pressure head, the liquid can be lifted to a high level.Centrifugal pump is a mechanical device, which consists of a body, impeller and arotating mean i.e. motor, engine etc. Impeller rotates in a stationary body, sucks the fluidthrough its axes, and delivers through its periphery. Impeller has an inlet angle, outletangle and peripheral speed, which affect the head and discharge. Impeller is rotated bymotor or i.e. engine or any other device.

DESCRIPTION OF CENTRIFUGAL PUMP TEST RIG

Centrifugal Pump Test Rig consists of a sump, a centrifugal pump, and AC motor andmeasuring tank. To measure the head, pressure and vacuum gauges are provided. Tomeasure the discharge, a measuring tank is provided. Flow diversion system is providedto divert flow from sump tank to measuring tank and from measuring tank to sump tank.A valve is provided in pipe line to change the rate of flow.


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UTILITIES REQUIRED

1. Electricity supply: Single phase, 220 V AC, 50 Hz, 5 15 amp socket with earth

connection.2. Water supply.3. Drain required.4. Bench area required: 1.5 m x 0.75 m5. Tachometer for RPM measurement


Starting procedure

1. Clean the apparatus and make tanks free from dust.

2. Close the drain valves provided.3. Fill sump tank with clean water and ensure that no foreign particles are there.

4. Open flow control valve given on the water discharge line and control valve given onsuction line.

5. Ensure that all ON/OFF switches given on the panel are at OFF position.

6. Set the desired speed of pump with the help of step cone pulley arrangement.

7. Operate the flow control valve to regulate the flow of water discharged by the pump.

8. Operate the control valve to regulate the suction of the pump.

9. Record discharge pressure by means of pressure gauge, provided on discharge line.

10. Record suction pressure by means of vacuum gauge, provided at suction of the pump.

11. Record the power consumption by means of energy meter, provided in panel.

12. Measure the flow of water, discharged by the pump, using stop watch and measuringtank.

13. Repeat the same procedure for the rest of the two speeds of motor / pump.

Closing Procedure

1. When experiment is over, open gate valve properly provided on the discharge line.


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2. Reduce the RPM of the pump with the help of DC drive.

3. Switch OFF the pump first.

4. Switch OFF power supply to panel.OBSERVATION AND CALCULATION

EMC = 3200 Pulses / KwhA = 0.128 m2

= 1000 Kg / m2

m = 0.8 (assumed)g = 9.81 m / s2

hpg = 1 m

OBSERVATION TABLE:

Sr. No. N,RPM

Pd,Kg/cm2

PS,mm Hg

R1,cm

R2,cm

t,sec

tp,sec

To plot head vs discharge and pump efficiency vs discharge.CALCULATIONS :

P 3600

Ei = -------- x ------------- , kW = -------------------- kWtp EMC

Es = Ei x m , kW = ----------------------- kWR1 - R2

R = --------------- , m = ------------------------- m100


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A x RQ = -------------- , m3 / sec = ------------------------ m3 / sec

tPs

H = 10 x [ Pd + -------- ] + hpg , m of water = --------------- m of water760

x g x Q x HE = --------------------------- , kW = -------------------------- kW

1000

E00 = -------- x 100 % = --------------------- %E1E0

p = -------- x 100 % = --------------------- %Es

NOMENCLATURE:

A = Area of measuring tank, m2

EMC = Energy meter constant, Pulses / kW rh

Ei = Pump input, kW

Es = Shaft output, kW

g = Acc. dueto gravity, / m s2

H = Total Head, m of water

hpg = Height of pressure gauge from vacuum gauge, m

N = Speed of pump, r.p.m.

P = Pulses of energy meter

Pd = Delivery pressure, kg / cm2

Ps = Suction pressure, mmHg


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Q = Discharge, m3 / s

R = Rise of water level in measuring tank, m

R1 = Final level of water level in measuring tank, cm

R2 = Initial level of water level in measuring tank, cm

t = Time taken by R, sec

tp = Time taken by P, sec

= Density of fluid, kg / m3

p = Pump efficiency, %

0 = Overall efficiency, %

PRECAUTIONS AND MAINTENANCE

1. Never run the apparatus if power supply is less than 180 volts and above 230 volts.

2. Never fully close, the Delivery line and By-pass line valves simultaneously.

3. To prevent clogging of moving parts, run pump at least once in a fortnight.

4. Always use clean water.

5. If apparatus will not be in use for more than one month, drain the apparatuscompletely.

6. Always keep apparatus free of dust.

TROUBLESHOOTING

1. If rpm indicator is not displaying the rpm, check the distance of proximity switch and

adjust it to 2-3 mm.

2. If pump does not lift the water, open the air vent provided on the pump to remove theair from pump.

3. If panel is not showing input, check the fuse and main supply.


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Experiment No. 10

TITLE

PERFORMANCE CHARACTERSTICS OF FRANCIS TURBINE

OBJECTIVE:To study the operation of a Francis Turbine and determine the output power andefficiency of Francis Turbine.

INTRODUCTION:

Francis Turbine named after James Bichens Francis, is a reaction type of turbine formedium high to medium low heads and medium small to medium large quantities ofwater. The reaction turbine operates with its wheels submerged in water. The waterbefore entering the turbine has pressure as well as kinetic energy. The moment on thewheel is produced by both kinetic and pressure energies. The water leaving the turbinehas still some of the pressure as well as kinetic energy.


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THEORY:

Originally the Francis turbine was designed as a purely radial flow type reaction turbinebut modern Francis turbine is a mixed flow type in which water enters the runner radiallyinwards towards the centre and discharges out axially. It operates under medium heads

and requires medium quantity of water.DESCRIPTION FRANCIS TURBINE TEST RIG(1 kW):

The present set up consists of a runner. The water is fed to the turbine by means ofCentrifugal pump, radially to the runner. The runner is directly mounted on one end of acentral SS shaft and other end is connected to a brake arrangement. The circular windowof the turbine casing is provided with a transparent acrylic sheet for observation of flowon the runner. This runner assembly is supported by thick cast iron pedestal. Load isapplied to the turbine with the help of brake arrangement so that the efficiency of theturbine can be calculated. A draught tube is fitted on the outlet of the turbine. The set upis complete with guide mechanism. Pressure and vacuum gauges are fitted at the inlet and

outlet of the turbine to measure the total supply head on the turbine.UTILITIES REQUIRED:

1. Electricity supply : 3 phase, 440 V AC, 50 Hz, 5 kw with earth connection/

2. Water supply (200 liters)

3. Drain required.

4. Floor area required : 2m x 1m

5. Tachometer to measure RPM

6. Mercury for manometer, 250 gm.

EXPERIMENTAL PROCEDURE:

Starting Procedure

1. Clean the apparatus and make tank free from dust.

2. Close the drain valve provided.3. Fill sump tank with clean water and ensure that no foreign particles are there.

4. Fill manometer fluid i.e. Hg in manometer by opening the valves of manometer andone PU pipe from pressure measurement point of pipe.

5. Connect the PU pipe back to its position and close the valves of manometer.


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6. Ensure that there is no load on the brake drum.

7. Switch ON the pump with the help of the starter.

8. Open the air release valve provided on the manometer, slowly to release the air frommanometer. ( This should be done very carefully. )

9. When there is no air in the manometer, close the air release valves.

10. Now turbine is in operation.

11. Apply load on hanger and adjust the spring balance load by hand wheel just to releasethe rest position of the hanger.

12. Note the manometer reading, pressure gauge reading and vacuum gauge reading.

13. Measure the RPM of the turbine.

14. Note the applied weight and spring balance reading.

15. Repeat the same experiment for different load.

16. Regulate the discharge by regulating the guide vanes position.

17. Repeat the experiment for different discharge.

Closing Procedure:

1. When the experiment is over, first remove load on dynamometer.

2. Open the by-pass valve.

3. Close the ball valves provided on manometer.

4. Switch OFF pump with the help of starter.

5. Switch OFF main power supply.

OBSERVATION AND CALCULATION:

DATA:


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g = 9.81 m/sec2

w = 1000 Kg/m3

m = 13600 Kg/m3Cv = 0.98D = 0.08m

dB = 0.2 mdR = 0.012 mW3 = ----- kgW4 = ----- kg

OBSERVATION TABLE:

Sr. No. N,RPM

Pd,Kg/cm2

PS,mm Hg

h1,cm

h2,cm

W1,kg

W2,kg

CALCULATIONS:

PsH = 10 ( Pd + ----- ) , m of water = --------------- m of water

760

Q = V x A, m3/sec = ------------------ m3/sec

A = ----- d 2, m2 = --------------- m2

4

h1 h2h = ---------------- , m = ---------------- m

100


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V = Cv x 2gh x (m /w - 1) , m / sec = --------------------- m / sec w x g x Q x H

Ei = ------------------------- , kW = ------------------------ kW1000

T = ( W1 + W3 + W4 - W2 ) x g x Re , Nm = ---------------- Nm

dB + 2dRRe = ---------------- , m = -------------------------- m

2

2 x x N x TE0 = ------------------------- , kW = ------------------------kW

60 x 1000E0

t = --------- x 100 % = --------------------------- %Ei

NOMENCLATURE:

A = Cross-sectional area of pipe, m2

CV = Co-efficient of pitot tube

D = Diameter of pipe, m

dB = Diameter of brake drum, m

dR = Diameter of rope, m

Ei = Input power, kW

Eo = Output power, kW

g = Acceleration due to gravity, m / sec2

H = Total head, m

h = Differential pressure of manometer, m


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h1, h2 = Manometer reading at both points, cm

N = RPM of runner shaft

Pd = Delivery pressure, kg / cm2

PS = Suction Pressure, mm / Hg

Q = Discharge, m3 / sec

Re = Equivalent radius, m

T = Torque , N m

V = Velocity of water, m/s

W1 = Applied weight, kg

W2 = Dead weight (obtain from spring balance), kg

W3 = Weight of hanger, kg

W4 = Weight of rope, kg

w = Density of water, kg / m3

m = Density of manometer fluid i.e. Hg, kg / m3

t = Turbine efficiency, %

PRECAUTION AND MAINTENANCE INSTRUCTIONS

1. Never run the apparatus if power supply is less than 390 volts and above 420 volts.

2. To prevent clogging of moving parts, run pump at least once in a fortnight.

3. Always use clean water.

4. Drain the apparatus completely after experiment is over.

5. Always keep apparatus free from dust.

TROUBLESHOOTING


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1. If pump does not lift the water, the revolution of the motor may be reverse. Change theelectric connection to change the revolution.

2. If panel is not showing input, check the main supply.

Experiment No. 11

TITLE

PERFORMANCE TEST OF A PELTON WHEEL TURBINE

OBJECTIVES

To study the performance of Pelton wheel turbine and draw its characteristics at constantspeed and constant head.

THEORY

Hydro-power is one of the major cheap sources of power available one earth, andhence it is widely used for generation of electric power world wide. Water stored in thedam contains potential energy. The water flows through the turbine, so that power is


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generated by impact of water or reaction of water flow. The turbine drives a generatorwhich delivers electrical power. Thus, turbines are of great importance.

Turbines are basically of two types, viz. impulse turbines and reaction turbines. Inimpulse turbines, water coming from high head acquires high velocity. The high velocitywater jet strikes the buckets of the turbine runner and causes it to rotate by impact. In

reaction turbine, total head of water is partly converted into velocity head as itapproaches turbine runner and it fills the runner and pressure of water gradually changesas it flows through runner. In impulse turbine, the only turbine used now-a-days is PeltonWheel Turbine. In reaction turbines, Francis Turbine and Kalpan Turbine are theexamples.

The DYNAMIC Pelton wheel turbine consists of runner mounted over the mainshaft. Runner consists of buckets fitted to the disc. The buckets have a shape of doubleellipsoidal cups. The runner is encased in a casing provided with a Perspex window forvisualization. A nozzle fitted in the side of casing directs the water jet over the Spilteror center ridge of the buckets. A spear operates inside the nozzle to control the waterflow. On the other side of the shaft, a rope brake is mounted for loading the turbine.

PELTON WHEEL TURBINE TEST RIG 5 HP SPECIFICATIONS:-

1) Turbine Power 5 H.P. fitted with 18 number of buckets, mounted over the sumptank provided with nozzle and spear.

2) Pump 15 H.P. mono-block pump, Head 85m, Discharge 6lps provided with semiautomatic star-delta starter

3) Measurements a) Venturi meter with mercury manometer for discharge measurement.b) Rope brake pulley dia 0.270 meter with spring balance 50 Kgs. Capacity and beltthk. 6mm.c) Pressure gauge to note down the pressure 0 7 Kg/cm2 capacity.

EXPERIMENTAL PROCEDURE: -

1) Fill up sufficient water in the sump tank.2) Keep the venturimeter valves closed.3) Close nozzle by operating the spear. Press Green button of starter, hold it for 1-2seconds and release so that pump starts running.4) Observe direction of pump rotation during starting. It should be clockwise, as seenfrom fan end. If it is reverse, interchange any two phases supply line. If direction pump iscorrect, pressure gauge will read the pressure about 6 Kgs/cm2. If it is reverse, pressuregauge will read about 2 Kgs/cm2.5) Slowly open the nozzle. Turbine will start rotating. Adjust the spear so that turbine isrotating at 1000rmp.6) Put the load using loading stud. Open the nozzle, so that turbine is again rotating at1000rpm.


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7) Note down the readings in observation table.8) Repeat the procedure for different speeds, say 800 rpm, 600 rpm, 500 rpm.9) Release all the load. Keep spear at 1/4 opening. Load the rope brake with 5 Kg load.Note down the speed.10) Go on adding the load, without disturbing spear position. Note down head, speed,

discharge and load each time.11) Repeat the procedure for 1/2, 3/4 and full spear opening. This is a constant head test.

OBSERVATION TABLE: -

1) Constant speed test Turbine speed, N = RPM

S. No. Spring balancedifference

(Kg)

Manometerdifference(m of Hg)

Pressure gaugereading

(Kg/cm2)

Use similar table for different speeds.

2) Constant head test Spear opening 1/4, 1/2, 3/4, Full.Manometer difference m of HgPressure gauge reading Kg/cm2

S. No. Spring balance difference

(Kg)

Speed rpm


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CALCULATIONS : -

1) Head over the turbine -

Since 10 Mtr. of water head corresponds to 1 Kg/cm2.Therefore, H = Pressure Gauge Reading Kg/cm2 x 10 mtr.

2) Water flow rate

Q = Cd x a1 x a2----------------- x (2 ghw)0.5 m3/sec(a12 - a22) 0.5

Q = 0.02498 ( h in mtr ) 0.5 ----------- h = Manometer reading mtr.

Where,a1 = Inlet area of Venturimeter at dia. = 0.05m = 1.963 x 10-3 m2

a2 = Throat are of Venturimeter at dia = 0.04m = 1.25 x 10-3 m2

Cd = Co efficient of discharge = 0.98

hw = Water head across venture= Manometer difference (h) x 12.6 mtr of water

3) Power supplied to turbine

Pin = WHQ wattsWhere,

W = Specific weight of water = 9810 N/ m3

4) Brake Power

( 0.270 + 0.006 )T = ( Spring balance difference Kg ) x 9.81 x --------------------- N.m

22 x 3.14 x N x T


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Brake Power = ------------------------------ watts60

Note i) Turbine speed is to be noted from laboratory tachometer, which is not thepart of equipment.

ii) Belt the 6 mm (i.e. 0.006 mtrs.)

5) Specific Speed

N ( P ) 0.5

NS = -------------------H5/4

N ( P in / 0.75 ) 0.5

= ---------------------------

H

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N x 1.77 x ( P in ) 0.5

= --------------------------------H5/4

6) Overall efficiency of turbine

BP = --------- x 100 %

P inGraphs

1) Constant speed test -Plot the graph of load Vs efficiency and discharge Vs. B. P. and efficiency.

2) Constant head test Plot the graph of speed N Vs. B. P. andN Vs. overall efficiency for various spear openings

PRECAUTIONS

1) While putting ON the pump see that the nozzle is closed by the spear and load on thebrake drum is released.

2) Use clean water in the tank.

3) Operate all the controls and switches gently.


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4) Lubricate the bearings, before experiment.

5) Drain the water after completion of experiment.

6) It is necessary to prime the pump before starting.7) Open manometer cocks slowly and simultaneously so that mercury does not run awaywith the water.

Experiment No. 12 (A)

TITLE

A) PERFORMANCE TEST OF GEAR PUMP

OBJECTIVES

To study the gear pump (positive displacement pump) and analyze its performance byplotting a graph between discharge & head, speed & discharge and efficiency & head..

THEORY OF GEAR PUMP

Gear pump is positive displacement type pump. Gear pumps are widely used forhydraulic power packs used in machine tools of testing machines, because of simplicityof construction and compactness. Also, even the pump is positive displacement type, thedischarge through pump is continuous. This is an advantage over the reciprocatingplunger type pump. Being a positive displacement pump, it can discharge the liquid to


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higher discharge pressure than rotary centrifugal pumps. The DYNAMIC test rigconsists of a gear pump connected to a sump tank. A valve provided on discharge side ofpump controls the discharge pressure. Various measurements are provided so thatperformance of pump can be evaluated.

GEAR PUMP TEST RIG SPECIFICATIONS:

1) Gear Pump 1/2" BSP connections, rated speed 1440 rpm.

2) Motor 1 H.P., 1425rpm, 3 phase with 3 speed cone pulley and vee belt.

3) Measurements and controls a) Vacuum gauge at suction of pump.b) Pressure gauge at discharge line of pump. 0 7 Kg/cm2.c) Energy meter for motor input measurement, Measuring tank with stop clock for

discharge measurement.d) Gate valve for discharge pressure control.e) Valve to direct the oil either to sump tank or measuring tank.f) Pressure relief valve at discharge side.

4) Pump tank 160 ltr. capacity.

PROCEDURE

Fill up sufficient clean oil in the tank ( SAE 40, at least 35 ltrs.) Before puttingthe oil, the tank must be clean. Rotate the belt by hand to check for freeness of operation.

Ensure that pressure control valve is fully open. Make the electrical connections.Keep the valve, which directs the oil to sump, open. Now start the motor. Set thedischarge pressure with the help of valve and note down the observations. Repeat theprocedure for different pressures

Take similar observations by changing the pump speed.

OBSERVATIONS

Pump speed

S. No. DischargePressureKg/cm2

SuctionVacuum

Mm of Hg

Time for 5 ltr. oilin measuring tank

sec.

Time for 5 imp.of energy meter

sec.


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CALCULATIONS

1) Flow rate (discharge) -Let the time required for 10 ltr. be tm sec.

10 x 10-3

Therefore, discharge, Q = -------------------- m3/sec.tm

2) Discharge head Let discharge pressure be P Kg/cm2

1 Kg/cm2 pressure = 12.5 m head of oil

Vacuum, mm of Hg 132435

Suction head = --------------------------- x ----------------1000 7850

= 17 x vacuum m of oil

H = Total head= Suction head + discharge head + 1

3) Output power

W Q HO.P. = --------------- x Kw1000

Where,W = Specific weight of oil = 7850 N/m3

Q = Discharge, m3/sec.


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H = Total head

4) Input Power

Let time required for 5 impulsions be te.

5 3600I.P. = ---------- x ------------ Kw

te 1600

S.P. = I.P x 0.7 x 0.9

Efficiency of the motor is 70 % and transmission efficiency is 90 %.

5) Efficiency

O. Po = ----------- x 100 %

S. P6) Slip

Vs = Swept volume per rev. = 1.7 x 10-5 m3

[ N x Vs ] - Q% Slip = --------------------- x 100

[ N x Vs]

Where,N = Rotational speed of the pump, rps.

Plot the following graphs

a) Speed V/s discharge

b) Head V/s discharge

c) Head V/s efficiency

It is seen that

i) Discharge is directly proportional to speed.


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ii) Discharge slightly reduces with increasing head.

iii) As head rises, efficiency increases.

PRECAUTIONS

1) Never keep the sump lid open.

2) Always fill up clean oil in the lamp.

3) Always use SAE 40 oil for the pump.

4) Never disturb the setting of pressure relief valve.

5) Never use the heads above 7 Kg/cm2 of pressure gauge.

6) Always operate all the controls gently.

Experiment No. 12 (B)

TITLE

B) PERFORMANCE TEST OF RECIPROCATING PUMP

OBJECTIVES

To study the reciprocating pump (positive displacement pump) and analyze itsperformance by plotting a graph between discharge & head and speed & discharge.

THEORY

Reciprocating pump is a positive displacement plunger pump. It is often usedwhere relatively small quantity of water is to be handled and delivery pressure is quitelarge. Reciprocating pumps are widely used as Automobile Service Stations, ChemicalIndustries, or as metering and dosing pumps.


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The DYNAMIC apparatus consists of a three cylinder, double actingreciprocating pump mounted over the sump tank. The pump is driven by a variable speedd.c. motor. An energy meter dimmer measures electrical input to motor. Measuring tankis provided to measure discharge of the pump. The pressure and vacuum gauges providedto measure the delivery pressure and suction vacuum respectively.

RECIPROCATING PUMP TEST RIG SPECIFICATIONS

1. Reciprocating pump stroke length 16 mm, piston ..22 mm, double acting, withair vessel on discharge side, suction 20 mm discharge 20 mm.

2. D.C. shunt motor, 1 HP, variable speed, controlled by 4 AMP dimmer.

3. Measuring tank 400 mm x 400 mm x 450 mm height provided with gauge tubeand funnel for diverting the flow into measuring tank or sump tank.

4. Sump tank 600 mm x 900 mm x 600 mm height.5. Measurements -i) Pressure gauge 0 10 Kg/cm2 for discharge pressure.ii) Vacuum gauge 0 760 mm Hg for suction vacuum.iii) 1 Ph energy meter for motor input measurement.

EXPERIMENTAL PROCEDURE : -

1) Fill up sufficient water in sump tank.

2) Open the gate valve in the discharge pipe of the pump fully.

3) Check nut bolts and the driving belt for proper tightening.

4) Keep the speed control (Dimmer) knob at minimum position and switch on the supply.

5) Divert funnel into the measuring tank and slowly increase the pump speed, (say 500rpm) slightly close the discharge valve. Note down pump speed, delivery pressure,suction vacuum, time for 10 imps of energy meter and for flow measurement close themeasuring tanks drain valve, take time for 10 lits.

6) Repeat the procedure for different gate valve closing. Take care that discharge pressuredoes not rise above 8 Kg/cm2. [constant rpm test]

7) Change the speed and take readings for different gate valve openings. Repeat theprocedure for different speeds and complete the observation table. ( 600 rpm, 700 rpm )


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OBSERVATION : -

Sr.No.

PumpSpeed

RPM Np

DischargePressureKg/cm2

SuctionVacuum

Mm of Hg

Time for 10 ltrs.rise in measuring

tank, t sec.

Time for 10 imp. ofenergy meter te sec.

(Note Pump speed is to be measured with laboratory tachometer and it is not the

part of the equipment.)

CALCULATIONS

1)Volume per stroke = /4 x 1 x 3= /4 x (0.022)2 x (0.016) x 3

= 1.82 x 10-5 m3

/stroke

2) Theoretical discharge1.82 x 10-5 x Np

Qt = -------------------------- m3/sec60

3) Actual discharge0.01

Qa = --------- m3 / secTw

4) Suction headPs x 13.6

Hs = ------- ----------1000 1

Where,Sp. gravity of mercury = 13.6


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5) Delivery headHd = Discharge pressure, Kg/ cm2 x 10

(as 10 m of water = 1 Kg / cm2)

6) Total head Ht = Hs + Hd + 2 mtrWhere,

Fictional losses = 2 mtr.

7) Output power of pumpW. Qa. Ht

PW = --------------- Kw1000

Where,W = Specific weight of water = 9810 N / m3

Qa = Discharge m

3

/secHt = Total head. m

8) Input power to pumpLet the time required for 10 indication mean pulse of energy meter be te secthen,

10 x 3600IP = -------- --------- Kw

te 3200Where,

Energy meter constant is 3200 imp / kwhTaking motor efficiency 80 %, we have input shaft powerS.P. = I.P. x 0.80

9) Overall efficiency of pumpPW

o = -------- x 100 %SP

10) Coefficient of discharge of pumpActual discharge QaCd = -------------------------- = --------

Theoretical discharge Qt

11) SlipQt - Qa


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Slip = ----------------- x 100 %Qt

12) GraphsPlot the graph of head Vs discharge, input power and efficiency of the

pump ( at constant speed ). Plot the graph of speed Vs discharge for constant head.

PRECAUTIONS

1) Earthing is necessary.2) Clean water must be filled in sump tank.3) Operate all the controls gently. Do not disturb the by pass knob. ( at the top of thepump)4) Never allow to rise the discharge pressure above 8 kg / cm2.5) Before starting the pump ensure that discharge valve is opened fully and speed control

knob is at zero position.6) Do not close the discharge valve.7) 20 w 40 oil use in pump. ( keep oil level properly )8) Oil must be changed after 2 years. ( Drain nut is provided near the oil indicator )9) Do not run the pump more than 700 rpm.10) After completion of experiment drain all the water.

Documents

FluidMachines_labManual_2008_revised