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FM &HM
LAB MANUAL
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LIST OF EXPERIMENTS
1. Impact jet of water on vane
2. Performance testing on pelton wheel
3. Francis turbine on test ring
4. Performance test on centrifugal pump
5. Calibration of venturimeter
6. Calibration of orifice meter
7. Frictional losses in pipe flow
8. Loss of head due to sudden contraction
9. Performance test on multistage centrifugal pump
10. Performance test on reciprocating pump
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IMPACT OF JET OF WATER ON VANE
AIM: - To find the coefficient of impact of jet on flat circular and hemispherical vanes.
APPARATUS: - experimental set-up (counter weight, semicircular vane, horizontral flat
vane), stop watch.
GENERAL DESCRIPTION:
The apparatus consists of mainly (1) Nozzle housing, (2) Nozzle, (3) Vane, (4) Transparent
Tank
(5) Measuring Tank and (6) Sump.
Nozzle housing:
It is of M.S rigidly fixed to the bottom of the tank having transparent tube and suitable to
accommodate nozzle.
Nozzle: It is of Gun Metal machined and polished nozzle of 8 mm is supplied.
Vane:
It is of Gun Metal machined all over and interchangeable.
(1) Flat vane with normal input.
(2) Hemi Spherical vane with normal input.
Transparent tank:
To observe the flow and jet deflection the tank is fitted with transparent tube.
Measuring tank: It is of suitable size and provided with gauge glass, scale arrangement for
quick and easy measurements. A Ball valve is provided to empty the tank.
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Sump
It is of suitable size with a supply pump set of 1 HP operating on single phase 220-240V 50Hz
AC Supply, and a drain plug to drain the water when the unit is not in use.
Installation
Fix the transparent tube on the measuring tank with the help of four bolts and nuts provided.
Make sure that the discharge spout is exactly center of the vane and connect the necessary piping
to the apparatus.
Before commissioning
Check whether the nozzle housing, discharge pipe flange etc are fitted with gaskets to
prevent water leakage.
Check the gauge glass and meter scale assembly of the Measuring tank and see that it is
fixed water tight and vertical.
PROCEDURE:
1. Insert the required vane on the lever
2. Measure the differential levr arms and calculate the ratio of lever arms(2.0in this case).
3. Balance the lever system by means of counter weight for no load.
4. Place a weight on the hanger.
5. Open the gate valve and adjust the jet, so that the weight arm is balanced
6. Collect water in the collecting tank.
7. Note: (a) the pressure gauge reading P
(b) the weight placed W
(c) time for 5 cm. rise in the collecting tank t
8. Calculate the discharge by weight.
9. Calculate the vertical force.
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Tabular form
Vane
type.
Inlet pressure
Jet
velocity
V
m/sec
Time
taken for
Rcm rise
of water
T sec
Mass flow
rate M
kg/sec
Input
force
F kg
Counter
load
W kg
Vane
coeff.
2W/F
P
Kg/cm2
H
m
of water
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CALCULATIONS:
1. Area of the collecting tank A=0.3*0.3 m2
Rise in water level R= 0.05 m(say)
Actual taken = t sec
Actual flow rate Qa=AR/t m3/sec
Actual flow rate M=1000Qa kg/sec
2. pressure gauge reading = p kg/cm2
Then, water head h= (10p) m of water
Assuming the co-efficient of discharge of nozzle as unity,
Velocity head v2/2g=H
Velocity of jet v
Angle of deflection of the vane to the jet =T1-T2 deg
Mass flow rate of water = M kg/sec
The lifting force =change in momentum per sec.
in vertical F= M*V*(sinT1-sinT2)
For horizontal flat vane, T1=90deg and T2=0deg
F= (M*V)/g
For semicircular vane, T1 =90 deg and T2=-90
F= (2*M*V)/g
3. actual lifting force measured = W*liver arm ratio kg
Fact=2.0W
The efficiency of the jet=Fact/F
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PRECUTIONS:
See that there is no leakage of water from pipes.
RESULT:
Efficiency of the semicircular vane =
Efficiency of the flat vane =
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PERFORMANCE TEST ON PELTON WHEEL
AIM: To study the characteristics of Pelton wheel turbine
APPARATUS: Pelton wheel turbine test rig.
DESCRIPTION
An impulse turbine is a turbomachine in which kinetic energy from one or
more fast-moving jets is converted to rotational mechanical energy delivered to
the shaft of the machine. A nozzle transforms water under a high head into
a powerful jet. The momentum of this jet is destroyed by striking the runner,
which absorbs the resulting force. No pressure change occurs at the turbine
blades, and so the turbine doesn’t require a housing for operation. The conduit
bringing high-pressure water to the impulse wheel is called the pen-stock.
Impulse turbines are most often used in very high head applications. Several
types of impulse turbines have been invented, but only one has survived in
appreciable numbers to the present day, which is the Pelton turbine. The free
water jet strikes the turbine buckets tangentially. Each bucket has a high center
ridge so that the flow is divided to leave the runner at both sides. Pelton wheels
are suitable for high heads, typically above about 450 meters with relatively low
water flow rates. For maximum efficiency the runner tip speed should equal
about one-half the striking jet velocity. The efficiency can exceed 91 percent
when operating at 60-80 percent of full load.
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PROCEDURE:
1. keep the nozzle opening at about 3/8th
open position.
2. Prime the pump if necessary.
3. Close the delivery gate valve completely and start the pump.
4. After the motor starter has changed to delta mode and the motor is running at normal
speed, open the delivery gate valve until the venture pressure gauge indicate a differential
pressure of about 0.6to 0.65 kg/cm2 this corresponds to the design flow rate.
5. Note the turbine inlet pressure in the pressure gauge fixed in the nozzle bend. If the
pressure higher or lower than 4.6kg/cm2(design head 46 m of water), adjust the delivery
gate valve and/or nozzle opening to set to design inlet pressure. At the same time , ensure
that the flow rate does not exceed the design valve as large flow rates(indicated by larger
pressure difference in the venturimeter pressure gauges)will over load the motor.
6. Note the speed of the turbine.
7. Note the venturimeter pressure gauge reading.
8. Load the turbine by adding weight to the hangar.
9. Repeat the experiment for different loads.
For constant speed tests, at lower load the flow rate and inlet pressure is reducd by
closing the delivery gate valve.
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CALCULATIONS:
1. To deter mine discharge
Venturirmeter line pressure gauge reading = P1 kg/sq.cm
Venturirmeter throat pressure gauge reading =P2 kg/sq.cm
Pressure difference dh= (P1-P2)*10 m of water
Venturirmeter equation Q=0.0055√dH m3/sec
Note: Venturirmeter in let dia .D= 65mm
Throat dia ratio B=0.6
Discharge Q= Cd*A*B2*√(2*9.81*dH)/1-B
4
Where, Cd – venturimeter discharge coefficient-0.98
A- Inlet area- 3.14*d2/4
2. To deter mine head:
Turbine pressure gauge reading = G kg/sq.cm
Totel head H=G*10 m of water
3. Input to the turbine
In put = 9.81QH KW.
4. Turbine out put
Brake drum dia = 0.40m
Rope dia =0.015m
Equiealent drum dia =0.415m
Hanger weight-To =1 kg
Weight- =T1kg
Spring load = T2 kg
Resultant load-T = (T1-T2+To) kg
Speed of the turbin = N rpm
Turbine output = (0.314*D*N*T)/(102*60) KW
=0.000215NT. KW
Turbine efficiency=output/input
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TABULAR FORM FOR CLOSED CIRCUIT
S.
no Inlet
pres..
P
kg/sq.cm
Totle
Head
H
Pressure Gauges
Readings
Kg/cm2
Discharge
m³/sec
Speed
N
rpm
Wt. on
hanger
T1kg
Spring
balance
T2 kg
Net
weight
T kg
Input
Powr
I
KW
Outpt
Power
O
KW
Effiny
%
P1 P2 P1-P2
1.
2.
3.
4.
5.
6.
7.
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TABULAR FORM FOR CONSTANT SPEED
IMPORTANT FORMULA
Efficiency = Output power X 100
Input Power X frictional efficiency
Input Power = 9810 x Supply head in meters (H) x Discharge(Q) = W x Q x H kw;
1000
Frictional efficiency =85%= 0.85
S.
no Inlet
pres..
P
kg/sq.cm
Totle
Head
H
Pressure Gauges
Readings
Kg/cm2
Discharge
m³/sec
Speed
N
rpm
Wt. on
hanger
T1kg
Spring
balance
T2 kg
Net
weight
T kg
Input
Powr
I
KW
Outpt
Power
O
KW
Effiny
%
P1 P2 P1-P2
1.
2.
3.
4.
5.
6.
7.
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Discharge = K√h m³/sec
Where,
h = (P1 - P2) x 10 m
a1 a2 √2g
K = ------------------------
√ (a1² - a2²)
Where, a1= Diameter of the venturimeter inlet = 50 mm/0.05m
a2= Diameter of the Venturimeter throat = 25 mm /0.025m
P1 = Inlet pressure, P2 = Throat pressure
Output Power = 2ΠNT Kw.
60000
N = RPM of the turbine shaft
T= Torque of the turbine shaft
T= (W1-W2) x R x 9.81
W = Load applied on the turbine.
R = Radius of the brake drum with rope in meters = 0.12 meters
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PRECAUTIONS:
1. Do not start a motor without priming.
2. Do not starting the motor without closing the delivery gate valve completely.
3. Only after the starter has changed to delta mode from the start mode ,the delivery gate
valve should be open.
Note: do not operate the motor at very low voltage of 350V and below as this will draw
excessive current, leading to motor coil burn out.
RESULTS AND CONCLUSIONS:
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FRANCIS TURBINE TEST RIG
AIM: To study the characteristics of francis turbine.
APPARATUS: Francis turbine test rig.
THEORY:
Francis turbine is a reaction type hydraulic turbine to convert the hydraulic energy
into mechanical energy and electrical energy. Francis turbine are best suited for
medium heads say 40 m to 300 m. the specific speed range from 25 to 300.
The turbine test rig consists of a 3.72KW turbine supplied with a water from a
suitable 15 HP centrifugal pump through suitable pipe lines.
Water under pressure from pump enters through the guide vanes into the runner
while passing through the spiral casing and guide vanes a portion of the pressure
energy is converted velocity energy. Water thus enters the runner at a high velocity
and as it passes through the runner vanes, the remaining pressure energy converted
into kinetic energy. Due to the curvature of the vanes the KE is transformed into
the mechanical energy.
PROCEDURE:
1. Keep the guide vane at required opening (say 3/8th
).
2. Prime the pump if necessary.
3. Close the main sluice valve and then start the pump.
4. Open the sluice valve for required discharge when the pump motor switches from star to
delta mode.
5. Load the turbine by adding weight in the weight hanger. Open the brake drum cooling
water gate valve for cooling the brake drum.
6. Measure the turbine rpm wit tachometer.
7. Note the pressure gauge and vacuum gauge reading.
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8. Note the venturimeter pressure gauge reading.
9. Repeat the experiment for other loads.
10. For constant speed tests, the main sluice valve has to be adjusted to vary the inlet head
and discharge for varying loads(at given guide vane opening position.
11. The experiment can be repeated fir other guide vane position.
CALCULATIONS:
1 To deter mine discharge
Venturirmeter line pressure gauge reading = P1 kg/sq.cm
Venturirmeter throat pressure gauge reading =P2 kg/sq.cm
Pressure difference dh= (P1-P2)*10 m of water
Venturirmeter equation Q=0.013√dH m3/sec
Note: Venturirmeter in let dia .D= 100mm
Throat dia ratio B=0.6
Discharge Q= Cd*A*B2*√(2*9.81*dH)/1-B
4
Where, Cd – venturimeter discharge coefficient-0.98
B- Inlet area- 3.14*d2/4
2 To deter mine inlet head of water :
Turbine pressure gauge reading = G kg/sq.cm
Turbine vacuum gauge reading = Vmm of Hg
Total head H=10(G+V/760) m of water
3 Input to the turbine
In put = 9.81QH KW.
4 Turbine out put
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Brake drum dia = 0.30m
Rope dia =0.015m
Equivalent drum dia =0.315m
Hanger weight-To =1 kg
Weight- =T1kg
Spring load = T2 kg
Resultant load-T = (T1-T2+To) kg
Speed of the turbine = N rpm
Turbine output = (0.314*D*N*T)/(102*60) KW
=0.000162NT. KW
Turbine efficiency=output/input
TABULAR COLUMN FOR CLOSED CIRCUIT
S.
no Inlet
pres..
P
kg/sq.cm
Totle
Head
H
Pressure Gauges
Readings
Kg/cm2
Discharge
m³/sec
Speed
N
rpm
Wt. on
hanger
T1kg
Spring
balance
T2 kg
Net
weight
T kg
Input
Powr
I
KW
Outpt
Power
O
KW
Effiny
%
P1 P2 P1-P2
1.
2.
3.
4.
5.
6.
7.
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TABULA COLUMN FOR CONSTANT SPEED
PRECAUTIONS:
1. Do not start a motor without priming.
2. Do not starting the motor without closing the delivery gate valve completely.
3. Only after the starter has changed to delta mode from the start mode ,the delivery gate
valve should be open.
Note: do not operate the motor at very low voltage of 350V and below as this will draw
excessive current, leading to motor coil burn out.
RESULTS AND CONCLUSIONS:
S.
no Inlet
pres..
P
kg/sq.cm
Totle
Head
H
Pressure Gauges
Readings
Kg/cm2
Discharge
m³/sec
Speed
N
rpm
Wt. on
hanger
T1kg
Spring
balance
T2 kg
Net
weight
T kg
Input
Powr
I
KW
Outpt
Power
O
KW
Effiny
%
P1 P2 P1-P2
1.
2.
3.
4.
5.
6.
7.
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PERFORMANCE TEST ON CENTRIFUGAL PUMP
AIM: - To conduct a test on single stage centrifugal pump at various speeds to obtain the pump
characteristics.
APPARATUS: - centrifugal pump, stop watch, scale, collecting tank.
DESCRIPTION:
A centrifugal pump is a rotodynamic pump that uses a rotating impeller to
Increase the pressure of a fluid. It works by the conversion of the rotational
Kinetic energy, typically from an electric motor to an increased static fluid pressure.
They are commonly used to move liquids through a piping system. In
Pump terminology, the rotating assembly that consists of the shaft, the hub, the
Impeller blades and the shroud is called the impeller.
The performance of a pump is characterized by its net head h, which is defined
As the change in Bernoulli head between the suction side and the delivery
Side of the pump. h is expressed in equivalent column height of water.
The specific speed will be a constant for a particular pump, or pumps similar
to it. If we know the head, speed and the discharge desired, it is easy to
find the general type of rotodynamic pump that would prove satisfactory using
specific speed. But it is not really a speed, and is a dimensionless number. The
speed and discharge used in the expression should be the speed and discharge
for maximum efficiency. Centrifugal pumps have low specific speeds among rotodynamic
pumps, ranging from 0.02 to 1.5.
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CALCULATIONS:
1. Discharge:
Area of tank A=0.5*0.5 sq m
Rise of level h =0.1 m
Volume collected =A h cu.m
=0.25 cu.m
Time taken = t sec
Discharge Q=volume/time
=0.025/t cu.m/sec
2. Head
Total head H=10(P+V/760)m of water.
3. Output of the pump
Output = 9.81*Q*H KW
4. Input of the motor
Energy meter constant N=1200revs per KWH
Time for 10 rev = T sec
Input to motor = (3600*10)/(N*T) KW
Efficiency of motor =80% (assumed)
Transmission efficiency = 90% (assumed)
Pump input = motor output*0.8*0.9 KW
=3600*10*0.8*0.9/(100*T)
=21.6/T KW
Pump efficiency =pup output /pump input
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PROCEDURE:
1. Loosen the V-belt by rotating the hand wheel of the motor bed and position the V-belt in
the required groove of the pully.
2. Prime the pump with water if required.
3. Close the delivery gate valve completely.
4. Start the motor and adjust the gate valve to required pressure and delivery
5. Note the following reading .
The pressure gauge reading P kg/sq.cm.
The vacuum gauge reading V mm of hg.
Time for 10 rev of energymeter disc-T secs.
Time for 10 cm rise in the collecting tank t- sec
Pump speedin rpm.
Take 3 or 4 sets of reading by varying the head from a maximum at shut off to a
minimum where gate valve is fully open. The experiment is repeated for other
pump speeds.
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TABULAR FORM
s.
no
Pump
speed
N
rpm
Pressure
gauge
reading
p
kg/sq.cm
Vacuume
gauge
reading
V m of
Hg
Total
head
(P + V)
Time
taken for
collecting
10cm rise
of water
In
collecting
tank
Time taken
for 10rev of
energyMeter
disc-T sec
Discharge
Q
Cu.m/sec
Input
Power
Kw
Output
Power
Kw
Efficiency
RESULTS AND CONCLUSIONS
Graphs for :-
1. Discharge Vs Head
2. Discharge Vs Input power
3. Discharge Vs Efficiency.
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CALIBRATION OF VENTURIMETER
AIM: To calibrate a given venture meter and to study the variation of coefficient of discharge of it with
discharge.
APPARATUS: Venturimeter, manometer, stop watch, experimental set-up.
DESCRIPTION:
The obstruction flow meter is a device used to measure the discharge of an
Internal flow. In these meters flow rate is calculated by measuring the pressure
Drop over an obstruction which is inserted in to path of the flow. There are many
Classifications according to the type obstruction used. The most commonly used
Categories are Venturi meter, orifice meter and nozzle meter.
Venturi meters are generally made from castings machined to close tolerances
To duplicate the performance of the standard design, so they are heavy,
Figure 2.1: Venturi meter
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Bulky, and expensive. Inside the venturi meter the fluid is accelerated through
a converging cone of angle 15�20o. The pressure difference between the upstream
Side of the cone and the throat is measured by using a differential manometer
And it provides a measure for the discharge. The conical diffuser section
Downstream from the throat with a lower angle 8�12o gives excellent pressure
Recovery and so overall head loss is low compared to other obstruction flow meters.
Venturi meters are self-cleaning because of their smooth internal shape.
PROCEDURE:-
1. Select the require flow meter.
2. Open it cocks and close the other cocks so that only pressure for the meterin use
communicated to the manometer.
3. Open the flow control valve and allow a certain flow rate.
4. Vent the manometer if required.
5. Observe the readings in the manometer.
6. Collect the tank in the collecting tank.
7. Close the drain valve and find the time taken for 10cm. rise in the tank.
CALCULATIONS:
Theoretical discharge for venturimeter
Difference in nmanometer level = h m. of Hg
The equivalent pressure drop = h(13.6-1) m of water
dH = 12.6 h m of water
Flow meter equations Q= K√dH m3/sec
Where, K- flow meter constant
Note: flow meter inlet dia D=20mm/25mm
Throat dia B=0.6
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Theoretical discharge Qt=A*B2*(2*9.81*dh)/(1.B4)
Where A=inlet area
Qa = flow rate
Cd=flow meter discharge coefficient
Qt= 0.000537√dH for 20mm pipelines
=0.000839√dH for 25mm pipelines
Actual discharge
Area of the collecting tank A=104*0.4 sq.m
Rise r = 0.1 m
Time taken =t sec
The actual discharged Qa=AR/t
=0.016/t
= Cd*Qt
Where Cd is the discharge constant
Hence cd=Qa/Qt
S. No. Venturi inlet diameter
d1
Throat Diameter
d2
1. 25mm 13.5 mm
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RESULTS AND CONCLUSIONS
S. No. Differential head in
m of mercury
Time for
(10 cm)
raise of
water level
t sec
Actual discharge
Qa cu. m/sec*10-3
Theoretical
discharge = Qt
cu. m/sec*10-3
cd = Qt/Qa
h1 h2
dH
m of
water
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CALIBRATION OF ORIFICE METER
AIM: -
To calibrate a given Orifice meter and to study the variation of coefficient of discharge of it with
discharge.
APPARATUS:
Orifice meter, manometer, stop watch, experimental set-up.
DESCRIPTION:
The orifice meter consists of a flat orifice plate with a circular hole drilled
in it. The construction is very simple and so cost is low compared to other
obstruction meters. There is a pressure tap upstream from the orifice plate and
another just downstream. Reduction of cross-section of the flowing stream in
passing through orifice increases the velocity head at the expense of pressure
head. This reduction of pressure between taps is measured using a differential
manometer and it gives a measure of the discharge. The pressure recovery is
poor compared to the Venturi meter.
The expression for discharge through any obstruction flow meter can be theoretically
obtained using the continuity and Bernoulli’s equations together. The
Bernoulli’s equation is defined for steady, incompressible and inviscid regions of
flow. Since the Bernoulli’s equation is a simplified form of energy equation, the
assumptions used for simplification must be satisfied when using it for practical
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PROCEDURE:
1. Select the require flow meter.
2. Open it cocks and close the other cocks so that only pressure for the meterin use
communicated to the manometer.
3. Open the flow control valve and allow a certain flow rate.
4. Vent the manometer if required.
5. Observe the readings in the manometer.
6. Collect the tank in the collecting tank.
7. Close the drain valve and find the time taken for 10cm. rise in the tank.
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CALCULATIONS:
Theoretical discharge for orificemeter:
Difference in mnanometer level = h m. of Hg
The equivalent pressure drop = h(13.6-1) m of water
dH = 12.6 h m of water
Flow meter equations Q= K√dH m3/sec
Where, K- flow meter constant
Note: flow meter inlet dia D=20mm/25mm
Throat dia B=0.6
Theoretical discharge Qt=A*B2*(2*9.81*dh)/(1.B4)
Where A=inlet area
Qa = flow rate
Cd=flow meter discharge coefficient
Qt= 0.000537√dH for 20mm pipelines
=0.000839√dH for 25mm pipelines
Actual discharge
Area of the collecting tank A=104*0.4 sq.m
Rise r = 0.1 m
Time taken =t sec
The actual discharged Qa=AR/t
=0.016/t
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=Cd*Qt.
Where Cd is the discharge constant Cd=Qa/Qt
Tabular column
RESULTS AND CONCLUSIONS
S. No. Differential head in
m of mercury
Time for
(10 cm)
raise of
water level
t sec
Actual discharge
Qa cu. m/sec*10-3
Theoretical
discharge = Qt
cu. m/sec*10-3
cd = Qt/Qa
h1 h2
dH
m of
water
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FRICTIONAL LOSSES IN PIPE FLOW
AIM:
The goal of this experiment is to study pressure losses due to frictional effects
(major losses) in fluid flow through pipes.
APPARATUS:
The pipe flow rig with pipes of different materials, a collecting tank with
stop watch to measure the discharge and a differential manometer to measure
the pressure drop in the test section.
DESCRIPTION:
When a fluid flows through a pipe, there is a loss of energy (or pressure) in
the fluid. This is because energy is dissipated to overcome the viscous (frictional)
forces exerted by the walls of the pipe as well as the moving fluid layers itself. In
addition to the energy lost due to frictional forces, the flow also loses pressure as
it goes through fittings, such as valves, elbows, contractions and expansions. The
pressure loss in pipe flows is commonly referred to as head loss. The frictional
losses are referred to as major losses while losses through fittings etc, are called
minor losses.
PROCEDURE:-
1. Select the require pipe line.
2. Connect the pressure tapping of the required pipe line (or the pipe fitting for minor losses
study) to the manometer b opening the appropriate pressure cocks and closing all other
pressure cocks.
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3. Open the flow control valve in the pipe line and allow water to pass.
4. Vent the manometer at a reduce flow rate. Care should be taken to avoid spill over of
mercury into the header pipes while venting. Expermint should always be started by
slowly opening the control valve and simultaneously observing the mercury column in
the manometer. For accidental spill over, stop the experiment and recover the mercury
from the bottom of the header.
5. By controlling the valve, required flow rate can be obtain to get a particular Reynolds
number.
6. Note the pressure difference from the manometer mercury columns.
7. Collect the water in the collecting tank for a particular rise of level and note the time
taken.
8. Repeat the experiments if required at other flow rates.
CALCULATIONS:
Area of the collecting tank A= 0.4*0.4 sq.m
Rise of level R=0.1 m (say)
Volume collected =AR cu.m
Time taken =t sec
Discharge Q=(AR/t) cu.m/sec
1. Manometer reading (mercury filled):
Reading in the left limb=h1 m
Reading in the right limb=h2 m
Difference level=(h1-h2) m of Hg
Equivalent loss of water head = (13.6-1)*(h1-h2)
H=12.6(h1-h2) m of water
Major losses
2. Pipe line :
Diameter of the pipe line =d m
Area of the pipe a=3.12*d2/4 sq m
Velocity in the pipe V=Q/a m/sec
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Test length in the pipe l=1.25 m
3. Darcy’s constant-f
Head loss H=(4flv2/2gd)
Substituting the values,
L=1.25 m; g=9.81m/sq.sec
F=3.93Hd/v2
Tabular column:
s.no
Pipe
dia
m
Manometer
reading
Head
losses
H m of
water
Time
for R
cm rise
T sec
Flow
rate Q
cu.m/sec
*10-3
Pipe
area
A
sq.m*10
-3
Flow
velocity
V
m/sec
Friction
factor f
h1 m of
hg
h2 m of
hg
RESULTS AND CONCLUSIONS
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LOSS OF HEAD DUE TO SUDDEN CONTRACTION
AIM:-
To determine the coefficient of loss in sudden contraction.
APPARATUS: -
Experimental set-up, stop watch, manometer.
DESCRIPTION:
When a fluid flows through a pipe, there is a loss of energy (or pressure) in
the fluid. This is because energy is dissipated to overcome the viscous (frictional)
forces exerted by the walls of the pipe as well as the moving fluid layers itself. In
addition to the energy lost due to frictional forces, the flow also loses pressure as
it goes through fittings, such as valves, elbows, contractions and expansions. The
pressure loss in pipe flows is commonly referred to as head loss. The frictional
losses are referred to as major losses while losses through fittings etc, are called
minor losses.
PROCEDURE:-
1. Select the required pipe setting sudden expanission or contraction.
2. Connect the pressure tapping to the required pipe setting to manometer.
3. By operating the pressure cocks &closing the all remain cocks.
4. Open the flow control to the pipe line and allow water to pipe.
5. Pressure difference is measured in manometer.
6. Collect the water in the collecting tank&time taken for required rise of water.
7. Repeate this procedure for sudden contraction & bend flow fitting.
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CALCULATIONS:
1. Diameter of the pipe =d m.
Area of the pipe a=3.14*d2/4 sq.m
Velocity in the pipe V=Q/a m/sec
Velocity head hv=V2/2g
2. Loss coefficient for bend and elbow
Loss coefficient K=loss/velocity head
K=H/hv.
3. Loss coefficient for sudden expanision:
Let section 1 correspond to uniform region up stream of the expansion and section
2 correspond to uniform regiondown stream of the expansion. then from
bernoullies theorem,
P1+V12/2g+Z1= P2+V2
2/2g+Z2+losses
Where P,V,Z are the static pressure, velocity and elevation of the water partical
and losses is the pressure loss due to the sudden expansion. Since elevation is
constant, rearranging the equation,
Loss=(P1-P2)+V12/2g(1-(V2/V1)
2)
But (P1-P2) is the measured static pressure difference H in the manometer and
V2/V1=a1/a2, the area ratio of the pipes. Hence,
Loss=H+V12/2g(1-(a1/a2)
2)
Since a1/a2=(d1/d2)2=0.25,
Loss=H+0.9375(V12/2g)
Loss coefficient K=loss(V12/2g).
4. Loss coefficient for sudden contraction:
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Let section 1 correspond to uniform region up stream of the expansion and section
2 correspond to uniform region downstream of the contraction. Then from
bernoullies theorem,
P1+V12/2g+Z1= P2+V2
2/2g+Z2+losses
Where P,V,Z are the static pressure, velocity and elevation of the water partical
and losses is the pressure loss due to the sudden expansion. Since elevation is
constant, rearranging the equation,
Loss=(P1-P2)+V22/2g((V1/V2)
2-1)
But (P1-P2) is the measured static pressure difference H in the manometer and
V1/V2=a2/a1, the area ratio of the pipes. Hence,
Loss=H+V22/2g((a2/a1)
2-1)
Since a1/a2=(d2/d1)2=0.25,
Loss=H-0.9375(V22/2g)
Loss coefficient K=loss(V22/2g)
PRECAUTIONS:
Readings will be taking without parallax error.
Apparatus the experiment carefully.
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TABULAR FORM
S. No.
Manometer
reading Head
loss
H m of
water
Time for
R cm
rise t sec
Flow
rate
Q
cu.m/sec
*10-3
Velocity
V m/sec
Velocity
coefficient
V2/2g m
of water
Loss
coefficient
K
h1m of
Hg
h 2 m of
Hg
1.
2.
3.
4.
5.
RESULTS AND CONCLUSIONS
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PERFORMANCE TEST ON MULTISTAGE CENTRIFUGAL
PUMP
AIM:
To conduct a test at various heads of given multistage centrifugal pump find its efficiency.
APPARATUS: -
multistage centrifugal pump, stop watch, collecting tank, piezometer,
Meter scale, driving unit, energy meter, pressure gauge, vacuum gauge.
DESCRIPTION:
A centrifugal pump is a rotodynamic pump that uses a rotating impeller to
increase the pressure of a fluid. It works by the conversion of the rotational
kinetic energy, typically from an electric motor to an increased static fluid pressure.
They are commonly used to move liquids through a piping system. In
pump terminology, the rotating assembly that consists of the shaft, the hub, the
impeller blades and the shroud is called the impeller. Centrifugal pumps are
used for large discharge through smaller heads.
Fluid enters axially through the hollow middle portion of the pump called
the eye, after which it encounters the rotating blades. It acquires tangential and
radial velocity by momentum transfer with the impeller blades, and acquires
additional radial velocity by centrifugal forces. The flow leaves the impeller
after gaining both speed and pressure as it is flung radially outward into the
scroll (or volute). The purpose of the scroll is to decelerate the fast-moving fluid
leaving the trailing edges of the impeller blades, thereby further increasing the
fluid pressure, and to combine and direct the flow from all the blade passages
toward a common outlet. If the flow is steady, incompressible and if the outlet
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and inlet diameters are are same, then, according to the continuity equation the
average flow speed at the outlet is identical to that at the inlet.
A centrifugal pump is a rotodynamic pump that uses a rotating impeller to
increase the pressure of a fluid. It works by the conversion of the rotational
kinetic energy, typically from an electric motor to an increased static fluid pressure.
They are commonly used to move liquids through a piping system. In
pump terminology, the rotating assembly that consists of the shaft, the hub, the
impeller blades and the shroud is called the impeller.
PROCEDURE:-
1. The internal plan dimensions of the collecting tank and the difference in level between the
centers of vacuum and pressure gauges (X) measured.
2. The speed of the pump and the energy meter constant (Ne) are noted.
3. The pump is primed with water.
4. With the delivery valve fully closed the driving unit is started.
5. By regulating the delivery valve, the discharge and hence the delivery head varied. For
each position of the delivery valve, form completely closed to maximum open
(a) Vacuum gauge reading (Hs)
(b) Pressure gauge reading (Hd)
(c) Time (T) taken for Nr revolution of the energy meter disc
(d) Time(t) taken for a particular rise(h) of water level in the collecting tank keeping output
valve completely closed
6. The above observations, for different delivery openings are tabulated. The efficiency of the
pump is computed.
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CALCULATIONS:
Internal area of collecting tank A=1*B
Actual discharge Qa=Ah/t
Weight of water W*Q*9810 N/S
Out put from the pump po=WH
Input the motor Pi=(360/Ne)*(Nr/T)*1000= watts
% efficiency of the pump = (output/input)*100
Speed of the pump=
Avg efficiency=
Energy meter constant=
Max effi. =
Internal diemensions of collecting tank
Length=
Breadth=
Difference in level between the centers of the vaccum and pressure gauge, X= m
A=10(l) m2
.
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TABULAR FORM
S.
No.
Suction
head
Delivery
hear
Total head
Ht=Hs+Hd+X
In (m)
Time
taken
for
5rev
of
energy
Meter
disc
Time
taken for
collecting
10 cm
rise of
water In
collecting
tank
Discharge
Q
Weight
of
water
Output
from
pump
Po
Input
to
motor
Pi
efficiency
m of
water
m of
water
RESULTS AND CONCLUSIONS
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PERFORMANCE TEST ON RECIPROCATING PUMP
AIM-
To determine the coefficient of discharge and efficiency of double acting reciprocating
pump.conduct a test at various heads of given reciprocating pump find its efficiency.
APPAATUS:
Reciprocating pump , stop watch , scale , collecting tank.
DESCRIPTION:
Reciprocating pump is a positive displacement pump, which causes a fluid to
move by trapping a fixed amount of it then displacing that trapped volume into
the discharge pipe. The fluid enters a pumping chamber via an inlet valve and
is pushed out via a outlet valve by the action of the piston or diaphragm. They
are either single acting; independent suction and discharge strokes or double
acting; suction and discharge in both directions.
Reciprocating pumps are self priming and are suitable for very high heads
at low flows. They deliver reliable discharge flows and is often used for metering
duties because of constancy of flow rate. The flow rate is changed only by
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adjusting the rpm of the driver. These pumps deliver a highly pulsed flow. If a
smooth flow is required then the discharge flow system has to include additional
features such as accumulators. An automatic relief valve set at a safe pressure is
used on the discharge side of all positive displacement pumps.
PROCEDURE:-
1. Fillup the sufficient water in the sump tank.
2. Fill up the vessel for about 2/3rd
capacity.
3. Open the gate valve in the discharge pipe of the pump fully.
4. Check rate bodes driving belt for properly tighten.
5. Divert funnels into measuring tank and slowly increase the pump speed slightly close the
discharge valve and note down the varies readings.
6. In the observations table repeat the procedure for different gate valve openings. Take care
that discharge pressure does not rise above 4 kg/m2.
CALCULATIONS:
1. Volume per stroke =2πR12
2. Theoretical discharge Qth= m3/sec
3. Suction head =Hs-suction volume of Hg*(Pgh-pw_
4. Where рgh= specific gravity of mercury=13.6
5. рw =Sp. Gravity of water =1000
6. Hg = 12.6*suction valve
7. Head= Hd-discharge pressure kg/cm2*10
8. Total head = Hd-discharge pressure kg/cm2*10
9. Actual discharge Qa=0.016/t
10. Output power of pump Po=(wQaHt/1000)=(n/te)*(3600/600)kw
11. Number of pumps =( Po/Sp)*100
12. Coefficient of discharge of the pump= Qa/Qth
13. Slip =((Qth-Qa)/Rl)*100
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TABULAR FORM
Suction
gauge
reading
m of
Hg.
Delivery
gauge
reading
kg/sq.cm
Sucti
on
head
Speed
rpm
Total
head
(P + V)
meters
Time
taken for
10cm
rise
sec
Actual
Discharge
Q
Cu.m/sec
Input
Power
Kw
Qth
%of
slip
Shaft
power
w
Delivery
head
m
%of
pump
Precautions:
1. Head is discharge ip pump speed is discharge at constant head.
2. Operate all the count.
3. Never allow the rise discharge above 4kg/sq.m
4. Always use clean water for equipment.
5. Pump speed is tube measured with tachometer and is not part of the equipment
RESULTS AND CONCLUSIONS
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