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St.MARTIN’S ENGINEERING COLLEGE

DEPARTMENT OF

MECHANICAL ENGINEERING

FM&HM LAB

II YEAR II SEM

A.Y.2016-17

Document No:

SMEC/ME/LAB/

MANUAL/FMHM

DATE

OF

ISSUE:

01-07-2016

COMPLIEDBY:

K.V.N.PARVATHI

VERIFIED BY:

PROF.S.VEERMANI

AUTHORISED BY

D.V.SRIKANTH

HEAD OF THE DEPARTMENT

EXPERIMENT-1 IMPACT OF JETS ON VANES 1.1OBJECTIVE: To find the coefficient of impact of jet on a flat circular and hemispherical

vane. 1.2RESOURCES:

S.NO Name of the equipment QTY

1 Impact of jet apparatus

2 Stop watch.

3

4

1.3 PRECAUTIONS: 1. Water flow should be steady and uniform

2. The reading on the scale should be taken without an error 3. The weight should be put slowly & one by one.

4. After changing the vane the flask should be closed tightly

1.4: Graph: Draw the graph Fa vs V2. From this compute the value of

the co-efficient of impact

MODEL GRAPH

V2

Fa

1.5 Procedure:

1) Fix the required diameter jet, and the vane of required shape in position and

zero the force indicator

2) Keep the delivery valve closed and switch on the pump

3) Close the front transparent cover tightly

4) Open the delivery valve and adjust the flow rate of water as read on the Rota meter 5) Observe the force as indicated on force indicator

6) Note down the diameter of the jet, shape of vane, flow rate and force and

tabulate the results

7) Switch off the pump after the experiment is over and close the delivery valve. 1.6 Theory:

A jet of water issuing from a nozzle has some velocity and hence it possesses

a certain amount of kinetic energy. If this jet strikes an obstruction (plate) plated in

its path, it will exert a force on the obstruction. This impressed force is known as

impact of the jet and it is designated as hydrodynamic force. This force is due to

the change in the momentum of the jet as a consequence of the impact. This

force is equal to the rate of change of momentum i.e.; the force is equal to (mass

striking the plate per second) x (change in velocity)

The amount of force exerted depends on the diameter of jet, shape of vane,

fluid density, and flow rate of water. More importantly, it also depends on whether

the vane is moving or stationary. In our case, we are concerned about the force

exerted on the stationary vanes.

Flat Plate:

Inclined plate:

Where g = 9.81 m/sec2

A = area of the jet in m2

ρ = Density of water in Kg/m3

v = velocity of the jet in m/sec

Ө= Angle the deflected jet makes with the axis of striking jet, in

degrees

Ft =The theoretical force acting parallel to the direction of the

jet

Fa= Actual Force developed as indicated by analogue force indicator

1.7 Description:

It is a closed circuit water re- circulation system consisting of sump tank,

mono block centrifugal pump set, jet/vane chamber, Rota meter for flow rate

measurement, direct reading analog force indicator. The water is drawn from the

sump tank by mono block centrifugal pump and delivers it vertically to the nozzle

through rotameter. The rotameter is a direct indicating flow rate instrument which

gives the discharge in litters per minute (LPM) which is determined by the top

position of the float. The flow control valve is also provided for controlling the water

into the nozzle. The water is issued out of nozzle as jet. The jet is made to strike

the vane, the force of which is transferred directly to the force indicator. The force

is read in Kgf or N. The provision is made to change the size of nozzle / jet and the

vane of different shapes.

1.8 Table of Readings

Diameter of jet

Vane type

Discharge

‘Q’

Force Indicat

or Reading

Fa

mm

m

m

3/sec

Kg f

Table of Calculations

Velocity

V

Actual

Force Fa

Theoretical Force

Ft

Co-efficient

of Impact

m/sec

N

N

1.9 Observations:

D = Diameter of Jet = 8 mm = 8 x 10-3

m Flat Plate,

Theoretical force, Ft = ρAV2

N Where, ρ= Density of Water = 1000 Kg/m

3

A = Area of Jet =ΠD2/4 m2

D = diameter of jet = 8 x 10-3

m V = Velocity = m/sec

Actual force, Fa

Fa = mg N

Co-efficient of Impact=Fa/ Ft

Inclined plate.

Theoretical force, Ft = ρAV

2 sin

2 θ N

Where, ρ= Density of Water = 1000 Kg/m

3

Actual force, Fa

Fa = mg N

Co-efficient of Impact=Fa/ Ft

1.10Result: Value of the coefficient of impact for flat and inclined vane

1.11Viva Questions:

t

1. Define the term Impact of Jet?

Ans. The liquid comes out in the form of a jet from the outlet of a nozzle, which

is fitted to a pipe through which the liquid is flowing under pressure. If some plate, which may be fixed or moving, is placed in the path of the jet, a force.

2. Write the formula for force exerted by a jet of water on a stationary &

moving plate? Ans. Fx= ρaV2

---- for a stationary vertical plate

=ρaV2

sin θ--- for an inclined stationary

plate = ρa (V-u)2

---- for a moving

vertical plate =ρa(V-u)2

sin2θ--- for an

inclined moving plate Where V=Velocity of the jet

u= Velocity of the plate in the direction of jet a =Area of cross section of the jet

θ =Angle between the jet & the plate for inclined plate 3. Write the formula for force exerted by a jet of water on a curved plate at

center & at one of the tips of the jet?

Ans. Fx=ρaV2

(1+cosθ) ---- for curved plate & jet strikes at the centre

=ρaV2

(1+cosθ) ---- for curved plate & jet strikes at one of the tips of the jet Where V=Velocity of the jet

a =Area of cross section of the jet θ =Angle between the jet & the plate for inclined plate

4. What is an impulse momentum equation?

Ans. The liquid comes out in the form of a jet from the outlet of a nozzle, which

is fitted to a pipe through which the liquid is flowing under pressure. If some plate, which may be fixed or moving, is placed in the path of the jet, a force is

exerted by the jet on the plate. This force is obtained from Newton’s second law of motion or from impulse-momentum equation.

1.11 LAB ASSIGNMENT:

1. Define the terms momentum, moment & impulse?

Ans. When a force (Push or pull) is applied on the bodies it tries to change the state of rest or state of motion of those bodies. The amount of force applied

is equal to the rate of change of momentum, where momentum is the product of mass and velocity

2. Explain the term dynamic machines. Ans. Dynamic machines: The term dynamic means power. Dynamic machines

meaning power machine, which receives the energy from the flowing fluid in the form of momentum and coverts the change in momentum into useful work.

3. What is an impulse turbine?

Ans. In impulse turbine a high velocity jet issued. From nozzle strikes a series of suitably shaped buckets fixed on the periphery of a wheel. The wheel get

resulting momentum and it gets rotated and thus we get the mechanical energy from the turbine.

EXPERIMENT-2 PERFORMANCE TEST ON PELTON WHEEL TURBINE

2.1OBJECTIVE: To conduct performance test on the given Pelton wheel turbine 2.2RESOURCES:

S.NO Name of the Equipment Qty

1 A Pelton Turbine

2 A Supply pump unit to supply water

3 Flow Measuring unit consisting of a

Orificemeter and Pressure Gauges

4 Piping system

5 Sump

2.3 Precautions:

1) After taking one set of reading release the tension of the belt

and run the turbine at no load condition for at least five minutes.

2) By pass valve should always fully open at the time of starting

the pump.

3) Before starting the pump check the manometer tapings.

4) Tachometer should not touch with any moving part at the time of r.p.m.

measurement.

5) After experiment drain off the water from the tank

2.4 Graphs:

1. Speed Vs Discharge 2. Speed Vs Input power 3. Speed Vs Efficiency Model Graphs:

Head (H) = Constant

Discharge Efficiency

Power

Speed

2.5 Procedure: 1) Connect the supply water pump-water unit to 3 ph, 440V, 30A, electrical

supply, with neutral and earth connections and ensure the correct direction of

the pump motor unit.

2) Keep the Gate Valve and Spear valve closed.

3) Press the green button of the supply pump starter. Now the pump picks- up the

full speed and becomes operational.

4) Slowly open the Spear Valve so that the turbine rotor picks the speed

and conduct Experiment on constant speed.

5) Note down the speed, load, and pressure gauge readings. Tabulate the readings.

2.6 THEORY:

Hydraulic turbines are the machines which use the energy of water (Hydro

power) and convert it into mechanical energy. Thus the turbine becomes the

prime mover to run the electrical generators to produce electricity. Pelton wheel is

an impulse type of turbine where the available energy is first converted into the

kinetic energy by means of an nozzle, the high velocity jet from the nozzle strikes

a series of suitably shaped buckets fixed around the rim of a wheel. The buckets

changes the direction of the jet without changing its pressure, the resulting change

in momentum set bucket and wheel in to rotatory motion and thus mechanical

energy made available at the turbine shaft. The water after passing through the

turbine unit enters the collecting tank.

2.7Description:

Water turbines are tested in the hydraulic laboratory to demonstrate the

principles of water turbines, to study their construction, and to give the students a

clear knowledge about the different types of turbines and their characteristics.

Turbines shall be first tested at constant net supply head by varying the load,

speed and spear setting. However the net supply head on the turbines tested in

which case the power developed by the turbine and the best efficiently speed will

also be reduced. The output power from the turbine is calculated from the readings

taken on the brake and the speed of the shaft. The input power supplied to the

turbine is calculated from the net supply head on the turbine and discharge

through the turbine. Efficiency of the turbine being the ratio between the output

and input and can be determined from these two readings. The discharge is

measured by the 50mm orificemeter and with the Pressure Gauges. Supply Head is

measured with the help of the pressure gauge. The speed of the turbine is

measured with digital tachometer fitted to the turbine. After starting and running

the turbine at normal speed for the sometime, load the turbine and take readings.

Note the following:

1. Net supply head (pressure gauge reading + height of the gauge center

above the center line of The jet).

2. Discharge (Pressure Gauges readings)

3. Turbine shaft speed.

4. Alternator readings

For any particular setting of the spear first run the turbine at light load and

then gradually load it. The net supply head on the turbine shall be maintained

constant at the rated value and this can be done by adjusting the gate valve fitted

just above the turbine. A typical tabular form is given below for the convenience

during experiment

2.8 SPECIFICATIONS: PELTON TURBINE

1. Power output: 1 K Watts

2.No. of Buckets: 17Nos.

SUPPLY PUMPSET

1. Capacity : 5 HP

2. Type : Centrifugal

FLOW MEASURING UNIT

1. Size of Orificemeter:50 mm

2. Diameter of inlet : 50 mm

2.9 TABLE OF READINGS: S.No

Inlet pressure

(P) Kg/cm2

Total

Head (H)

m of water

Speed

(N)

rpm

OrificemeterPressure Gauge Readings (Kg/cm2)

P1

P2

dh=P1-P2

TABLE OF CALCULATION: Discharge(Q) m3/sec

Output voltage(V) volts

Output current(I) Amps

Turbine Output power(KW)

Turbine Input power(KW)

Efficiency %

2.10 IMPORTANT FORMULAE:

(i) To determine discharge:

Orificemeter line pressure gauge readings=P1 kg/cm2 Orificemeter throat pressure gauge readings=P2 kg/cm2 Pressure difference dh=(P1-P2)X10 m of water

Orificemeter equation Q=0.00204(dh)0.5 m3/sec (ii) To determine Head: Turbine Pressure gauge reading = P kg/cm2

Total Head H = Px10 m of water (iii)To determine input to the turbine: Input power =9.81XQxH kw (iv)To determine output : Alternator output voltage V = volts Alternator output current I = amps Alternator output = VXI Watts Alternator efficiency =0.7 Turbine output = Alternator output/Efficiency =VXI/0.7 Watts = VXI/(1000x0.7) kw (v) To determine Efficiency: Efficiency=(Output power/Input power)x100= %

2.11Results: 1. Input power = kw

2. Output power = kw 3. Efficiency of pelton turbine = %

2.12Viva Voce Questions: - 1. What is the basic difference between an impulse & reaction turbine?

Ans. If at the inlet of the turbine, the energy available is only kinetic energy, the turbine is known as impulse turbine. If at the inlet of the turbine, the water possesses kinetic energy as well as pressure energy, the turbine is known

as reaction turbine 2. What is the basic difference between a tangential flow & radial flow turbine?

Ans. If the water flows along the tangent of the runner, the turbine is known at tangential flow turbine. If the water flows in the radial direction through the runner, the turbine is called radial flow turbine

3. What is basic difference between axial flow & mixed flow turbine?

Ans. If the water flows through the runner along the direction parallel to the axis of the runner, the turbine is called axial flow turbine. If the water flows

through the runner in the radial direction but leaves in the direction parallel to the axis of rotation of the runner, the turbine is called mixed flow turbine

4. What do you mean specific speed of a turbine?

Ans. It is defined as the speed of a turbine which is identical in shape, geometrical dimensions, blade angles, gate opening etc., with the actual turbine but of such a size that it will develop unit power when working under unit head.

(Ns) 5. Define unit speed, unit power & unit discharge?

Ans. Unit speed is defined as the speed of a turbine working under

a unit head (i.e., under a head of 1m). (Nu)

o Unit discharge is defined as the discharge passing through a turbine, which is working under unit head (Qu)

o Unit power is defined as the power developed by a turbine, working under a unit head

6. Define hydraulic machines?

Ans. Hydraulic machines are defined as those machines which convert either hydraulic energy (energy possessed by water) into mechanical (which is further converted into electrical energy) or mechanical energy

into hydraulic energy. 7. Define turbines?

Ans. The hydraulic machines, which convert the hydraulic energy into mechanical energy, are called turbine.

8. The study of hydraulic machines consists of what?

Ans. It consists of study of turbines and pumps.

9. Define the term Gross head. Ans. The Gross head or Total head is the difference between the water level at

the reservoir (also known as head race) and the level at the tail race. (Hg)

10. Define net head? Ans. It is also called effective head and is defined as the head available at the inlet of the turbine. H=Hg-hf.

11. Define Hydraulic efficiency?

Ans. It is defined as the ratio of power given by water to the runner of a turbine to the power supplied by the water at the inlet of the turbine.

12. Define Mechanical efficiency?

Ans. It is defined as the ratio of power available at the shaft of the turbine

to the power delivered to the runner. 13. Define Volumetric efficiency?

Ans. It is defined as the ratio of the volume of the water actually striking the runner to the volume of water supplied to the turbine.

14. Define Overall efficiency?

Ans. It is defined as the ratio of power available at the shaft of the turbine

to the power supplied by the water at the inlet of the turbine. 15. The pelton wheel (or) pelton turbine is ---- a tangential flow impulse turbine. 16. Write the classification of hydraulic turbines according to the type of

energy at inlet? Ans. i) impulse turbine, and ii) reaction turbine 17. Write the classification of hydraulic turbines according to the direction of

flow through runner?

Ans. i) tangential flow turbine, ii) radial flow turbine, iii) axial flow turbine, and iv) mixed flow turbine.

18. Write the classification of hydraulic turbines according to the head at the inlet of turbine? Ans. i) high head turbine, ii) medium head turbine, and iii) low

head turbine. 19. Write the classification of hydraulic turbines according to the specific speed of

the turbine? Ans. i) low specific speed turbine, ii) medium specific speed turbine, and iii) high specific speed turbine,

20. Why the d raft tube is not used for Pelton turbine?

Ans. In case of pelton turbine all the K. E. is lost and draft tube is not used

because the pressure value is just the atmospheric so there is no requirement of draft tube.

21. What is the function of the casing? Ans. The function of the casting is to prevent the splashing of the water & to discharge water to tail race. It also acts as a safeguard against accidents.

EXPERIMENT-3 PERFORMANCE TEST ON FRANCIS TURBINE

3.1 OBJECTIVE: To conduct performance test on the given Francis turbine

3.2 RESOURCES:

S.NO Name of the equipment

QTY

1 Francis turbine experiment setup

2 Stop watch.

3

4

3.3 Precautions:

1. The main valve should be closed before starting the

machine.

2. Do not load the turbine suddenly.

3. Loading should be done gradually and at the same time supply of water should

b be increased so that the run at normal speed.

3.4 Graph: Plot Graph BP (Input Power) Vs Efficiency

3.5 Procedure:

1. Prime the pump and start it with closed gate valve.

2. Guide vanes in the turbine must be in closed position while starting the pump.

3. Now slowly open the gate valve and open the chock fitted to the pressure

gauge and see that the pump develops the rated head.

4. If the develops the required head, slowly open the turbine guide vanes by

rotating the hand wheel until the turbine attains the rated speed.

5. Load the turbine slowly and take the readings.

3.6 THEORY:

The model Francis Turbine is an inward mixed flow reaction turbine i.e. the

water under pressure enters the runner from the guide vanes towards the

center in radial direction and discharge out of the runner axially. The Francis

Turbine operates under medium head and also requires medium quality of water.

A part of the head acting on the turbine is transformed into kinetic energy and

rest remains as pressure head. There is a difference of pressure between the

guide vanes and the runner, which is called the reaction pressure and is

responsible for the motion of the runner. That is why a Francis Turbine is also

known as reaction turbine. In this turbine the pressure at the inlet is more then

that at the outlet. This means that the water in the turbine must flow in a closed

conduit, unlike the Pelton type where the water strikes only a few of the runner

buckets at a time. In the Francis turbine the runner is always full of water. The

movement of runner is affected by the change of both the Kinetic and potential

energies of water. After doing work the water is discharged to the tailrace

through a closed tube of gradually enlarging section. This tube is known as draft

tube. The free end of the draft tube is submerged deep in the tailrace water.

Thus the entire water passage, right from the headrace up to the tailrace,

totally enclosed.

3.7Experimental setup: The turbine is placed on a substantial concreted base. The supply pump set draws

water from the main tank and supplies it to turbine. A venturimeter is mounted to

measure the flow. A gate valve is provided just above the inlet of the turbine in

relation to the guide vane setting. A set of guide vanes is provided around the

periphery of the runner to control the load. The whole guide vane mechanism is

being operated through a hand wheel by suitable link mechanism.

3.8Technical Specification:

FRANCIS TURBINE 1. Rated Supply head

2. Discharge

3. Rated Speed

: 1.2 Meters : 2000 LPM : 1200 rpm

4. Power Output : 4 HP

3.9SPECIFICATIONS: FRANCIS TURBINE

1. Power output: 1 KWatts

SUPPLY PUMPSET

1. Capacity : 5 HP


FLOW MEASURING UNIT

1. Size of Venturimeter:50 mm

2.Throat Diameter ratio : 0.6


Inlet pressure

(P) Kg/cm2

Total

Head (H)

m of water

Speed

(N)

rpm

Venturimeter Pressure Gauge Readings (Kg/cm2)

P1

P2

dh=P1-P2






Efficiency %



Venturimeter line pressure gauge readings=P1 kg/cm2 Venturimeter throat pressure gauge readings=P2 kg/cm2

Pressure difference dh=(P1-P2)X10 m of water Venturimeter equation Q=0.0055(dh)0.5 m3/sec

(ii) To determine Head: Turbine Pressure gauge reading = P kg/cm2

Total Head H = Px10 m of water

(iii)To determine input to the turbine: Input power =9.81XQxH kw (iv)To determine output : Alternator output voltage V = volts Alternator output current I = amps Alternator output = VXI Watts Alternator efficiency =0.7 Turbine output = Alternator output/Efficiency =VXI/0.7 Watts = VXI/(1000x0.7) kw (v) To determine Efficiency: Efficiency=(Output power/Input power)x100= %

3.12 Results: 1. Input power = kw

2. Output power = kw 3. Efficiency of Francis turbine = %

3.13Viva Voce Questions: - 1 What means reaction turbine? Ans. It means that the water at the inlet of the turbine possesses kinetic energy as well as pressure energy. As the water flows through the runner, a

part of pressure energy goes on changing into kinetic energy. 2 What is the function of draft tube in a reaction turbine? Ans. The pressure at the exit of the runner of a reaction turbine is generally less than atmospheric pressure. The water exit cannot be directly

discharge to the tail race. A tube or pipe of gradually increasing area is used for discharging water from the exit of the turbine to the tail race. This tube

increasing area is called draft tube.

3 Define specific speed of a turbine? Ans. It is defined as the speed of a turbine which is identical in shape, geometric

dimensions, blade angles, gate opening etc., with the actual turbine but of such a size that it will develop unit power when working under unit head. (Ns). It is

used in comparing the different types of turbines as every type of turbine has different specific speed.

4 List the various functions of surge tanks. Ans. Surge tanks have the following functions: 1. To control the pressure variations, due to rapid changes in the pipeline

flow, thus eliminating water hammer possibilities. 2. To regulate the flow of water to the turbines.

3. To reduce the distance between the free water surface and turbine, thereby reducing the water hammer effect on penstock. 4. It protects up stream tuner from high pressure rises.

5 Define degree of reaction and Euler’s Head. Ans. The degree of reaction (R) is defined as a ratio of change of pressure energy

in the runner to the change of total energy in the runner per kg of water.

Euler’s Head: It is defined as energy transfer per

unit weight.

6 Define governing of turbine?

Ans. It is defined as the operation by which the speed of the turbine is kept constant under all conditions of working. It is done automatically by means of a governor, which regulates the rate of flow through the turbines according to the

changing load condition on the turbine.

EXPERIMENT-4

KAPLAN TURBINE

4.1 OBJECTIVE: To study the characteristic curves of a Kaplan turbine at constant head condition. 4.2 RESOURCES:

S.NO Name of the equipment QTY

1 stop clock

2 meter scale

3 Kaplan turbine setup

4 3-phase power supply.

4.3 Precautions: -

1. The water in the sump tank should be clean.

2. To start and stop supply pump, keep gate valve closed. 3. It is recommended to close guide vanes before starting.

4.4 GRAPHS: -To study constant head characteristic curves of a Francis Turbine

plot the following graphs, i). Unit Speed, Nu on X- axis Vs Unit Power, Pu, on Y- axis ii). Unit Speed, Nu on X- axis Vs Unit discharge, Qu on Y- axis

iii). Unit Speed, Nu on X- axis Vs Expected Graphs: -

4.5 Procedure:- 1.Keep the butterfly valve and gate valve closed, 2.Press the green button of the supply pump starter. The pump picks up full

speed and become operational.

3.Now keep the butterfly valve opening at minimum 4.Slowly open the gate valve so that the Turbine runner picks up the speed and attains the maximum at full opening of the valve.

5.At one particular head on the Turbine note down the speed, head over notch,

wattage of electrical load bulbs in action, load on generator, energy meter reading and tabulate the readings 6.Repeat the step no. 5 at different electrical bulb loads and note down the readings. 7. After the experiment is over keep sphere valve and butterfly valve closed, and

switch-OFF the pump.

4.6 Theory: Kaplan turbine is a reaction turbine operated at low head. It consists of

guide vanes, runner, scroll casing and draft tube at the exit. Water turns through right

angles and guided through the wing graphs runner and 'thus rotating the runner shaft.

The runner has four blades, which can be turned about their own axis so that the angle

of inclination may be adjusted while the turbine is in operation. By varying the guide

vane angles, high efficiency can be maintained over a wide range of operating

conditions. After passing through the turbine, water enters into the collecting tank

through draft tube. Loading of the turbine can be done by electrical switches arrangement.

(Electrical loading)

P

4.7 DIAGRAM

4.8SPECIFICATIONS: KAPLAN TURBINE

1. Power output: 1 KWatts

SUPPLY PUMPSET

1. Capacity : 5 HP


FLOW MEASURING UNIT

1. Size of Venturimeter:100 mm

2.Throat Diameter ratio : 0.6


Inlet pressure

(P) Kg/cm2

Total

Head (H)

m of water

Speed

(N)

rpm

Venturimeter Pressure Gauge Readings (Kg/cm2)

P1

P2

dh=P1-P2






Efficiency %



Venturimeter line pressure gauge readings=P1 kg/cm2 Venturimeter throat pressure gauge readings=P2 kg/cm2 Pressure difference dh=(P1-P2)X10 m of water

Venturimeter equation Q=0.0131(dh)0.5 m3/sec (ii) To determine Head: Turbine Pressure gauge reading = P kg/cm2

Total Head H = Px10 m of water (iii)To determine input to the turbine: Input power =9.81XQxH kw (iv)To determine output : Alternator output voltage V = volts Alternator output current I = amps Alternator output = VXI Watts Alternator efficiency =0.7 Turbine output = Alternator output/Efficiency =VXI/0.7 Watts = VXI/(1000x0.7) kw (v) To determine Efficiency: Efficiency=(Output power/Input power)x100= %

4.11 Results: 1. Input power = kw

2. Output power = kw 3. Efficiency of Kaplan turbine = %

4.12 Viva Voce Questions: - 1.What is specific speed .What is the range of specific speed of Kaplan turbine? 2.what is the type of flow in Kaplan turbine? 3.What is the difference between Francis and Kaplan turbines?

EXPERIMENT-5

PERFORMANCE TEST ON SINGLE STAGE CENTRIFUGAL PUMP

5.1Objective: To conduct a test at various heads of given single stage

centrifugal pump and to find its efficiency.

5.2RESOURCES:


QTY

1 Single stage centrifugal

pump

2 stop watch

3 collecting tank

4

5.2 Precautions:-

1. Priming is must before starting the pump.

2. Pump should never be run empty.

3. Use clean water in the sump tank.

5.3 Graphs:-

1. Discharge Vs Head;

2. Discharge Vs Input power &

3. Discharge Vs Efficiency

5.4 Model Graph:

HEAD (H) Efficiency, η

Input Power

Discharge(Q)

5.5 Procedure:-

1. Start the motor keeping the delivery valve close.

2. Note down the pressure gauge and vacuum gauge reading by adjusting the delivery valve to require head say 0 meters. Now calculate the total head

(H).

Pressure Head = Kg/cm² x 10 = meters.

Vaccum Head = mm of hg x 13.6 meters

1000 Datum head = Distance between pressure and vacuum

gauge in meters Total head (H) = Pressure Head + Vacuum Head + Datum Head

3. Note down the time required for the rise of 10cm (i.e. 0.1m) water in

the collecting tank by using stop watch. Calculate discharge using below formula.

Discharge: - The time taken to collect some ‘x’ cm of water in the collecting tank

in m³/sec.

Q = A h

t

A = area of the collecting tank in m² (0.35m X 0.35m)

h = rise of water level taken in meters (say 0.1m or 10cm)

t = time taken for rise of water level to height ‘h’ in seconds.

4. Note down the time taken for ‘x’ revolutions of energy meter disk and calculate the Input power

Input power = X x 3600 x 0.60 Kw

C xT

0.6 = combined motor (0.75) and transmission losses (0.8).

X = No. of revolutions of energymeter disc (say 5 Rev.)

T = Time for Energy meter revolutions disc.in seconds

C = Energy meter constant

5. Now calculate the output power

Output power = W x Q x H Kw

1000

Where: W = Sp. Wt. of water (9810 N/m³)

Q= Discharge H = Total Head

6. Repeat the steps from 2 to 5 for various heads by regulating the delivery valve. 5.6 Theory:

Centrifugal pump consisting of one impeller the pump is called

the single stage centrifugal pump. The impeller may be mounted on the

same shaft. In this pump the liquid is made to rotate in a closed chamber

(volute casing) thus creating the centrifugal action which gradually builds

the pressure gradient towards outlet thus resulting in the continuous flow,

the pressure gradually.

5.7 Description:-

The Test Rig mainly consists of (1) single stage centrifugal pump set

(2) Panel Board, (3) Pressure and vacuum gauges to measure the head

(4) SS Measuring Tank to measure the discharge (5) Energy meter to measure the input to the motor and .(6) SS Sump.

MULTI STAGE CENTRIFUGAL PUMPSET:

The pump set is of special design, horizontal spindle, and vertical split case. The pump is of such a size, type & design that 1) The total head 2) Discharge and 3) Power requirements at normal speed is well suited for the experimental purposes in technical institutions.

A.C. MOTOR: The electric motor suitable for operation on 50 HZ A.C. Supply is provided.

GAUGES: Suitable range of pressure and vacuum gauges to measure the total

head on the pump with reasonable accuracy

SS MEASURING TANK:

It is provided to measure the discharge of the pump. The tank is complete with piezo meter and scale arrangement.

PIPING SYSTEM: Suitable piping system with pipes, bends and valves are provided.

A Simple strainer valve is provided on the suction side to prevent any foreign matter entering into the pump. The gate valve is provided in the delivery side to control the head on the pump. While starting the motor always keep the valve in close position.

PANEL BOARD: The Panel Board houses all the necessary electrical items, like switch

for the above pump set and an energy meter to read the power input and it is fitted with the unit on a strong iron base with sufficient height and with provisions for foundation.

INPUT POWER MEASUREMENT: A Kilowatt-hour meter is provided to measure the power input to the

motor. The energy meter constant (The Number of Revolutions per minute of the energy meter Disc) is stamped on the meter from this the input power can be easily calculated.

SS SUMP: Is provided to store sufficient water for independent circulation

through the unit for experimentation and arranged within the floor space of the main unit. 5.8 Introduction:-

Closed Circuit Self sufficient portable package system Experimental Single stage Centrifugal pump Test Rig is designed to study

the performance of the Single stage Centrifugal pump. In this equipment one can study the relationship between

1. Discharge Vs Head

2. Discharge Vs Input power


The apparatus is designed to study the performance of a single stage

Centrifugal Pump. The readings to be taken on the single stage centrifugal

pump are (1) Total Head (2) Discharge (3) Power input and (4) Efficiency. Provision has been made to measure all these and hence the complete

characteristics of the single stage Centrifugal pump in question can be studied.

First prime the pump and start the motor. While starting closing and

delivery valve and the gauge cocks. Then slowly open the delivery valve and adjust to the required total head. The total head is measured with the

help of the pressure gauge. Total head is the sum of the pressure head, Velocity head and the datum head.

Discharge is the amount of liquid the pump delivers over a definite

period of time. It is usually expressed in liter per minute. The actual discharge is measured with the help of the measuring tank. In this case

the power input into the pump cannot be measured directly. Hence the power input into the AC motor is measured with the help of the energy

meter connected in the line.

Efficiency is the relation between the power input into the pump and

the power output from the pump. The power output from the pump is directly proportional to the total head and discharge. As the power input

into the pump cannot be measured the power input into the motor only is taken into account and the overall efficiency of the pump is calculated.

If the total head (H) is measured in meters and the discharge (Q) in

liter per minute, the HQ/6120 gives the output in kW. The kilowatt input to the motor is measured with the help of the meter constant stamped on

the energy meter. The efficiency is calculated by dividing the output by input.

For a particular desired speed of the pump, the entire above variable can be studied individually, thus the complete characteristics can

be studied.

5.9 Table of Readings:-

5.10 Table of Calculations:-

Total Head

H

Discharge

Q

INPUT

Powe

r

OUT PUT

Power

%η of pump

m

m3/ sec

KW

KW

5.12 RESULTS:-

1. Input power = kw

2. Output Power = kw

3. %η of pump = 5.14 VIVA QUESTIONS: 1. What is the difference between single and multistage centrifugal pump? 2.What is the purpose of impellars in pump?

EXPERIMENT-6

PERFORMANCE TEST ON MULTISTAGE CENTRIFUGAL PUMP

6.1OBJECTIVE:To conduct a test at various heads of given multistage

centrifugal pump and to find its efficiency.

6.2 RESOURCES :


QTY

1 Multistage centrifugal pump

2 stop watch

3 collecting tank

4

6.3 Precautions:-

1. Priming is must before starting the pump.

2. Pump should never be run empty.

3. Use clean water in the sump tank.

6.4 Graphs:-

1. Discharge Vs Head;

2. Discharge Vs Input power &


Model Graph:

HEAD (H) Efficiency, η

Input Power

Discharge(Q)

6.5 Procedure:-

1. Start the motor keeping the delivery valve close.

2. Note down the pressure gauge and vacuum gauge reading by adjusting

the delivery valve to require head say 0 meters. Now calculate the total head (H).


Vaccum Head = mm of hg x 13.6 meters

1000 Datum head = Distance between pressure and vacuum

gauge in meters Total head (H) = Pressure Head + Vacuum Head + Datum Head

3. Note down the time required for the rise of 10cm (i.e. 0.1m) water in

the collecting tank by using stop watch. Calculate discharge using below

formula.

Discharge: - The time taken to collect some ‘x’ cm of water in the collecting tank in m³/sec.

Q = A xh/ t


h = rise of water level taken in meters (say 0.1m or 10cm)

t = time taken for rise of water level to height ‘h’ in seconds.

4. Note down the time taken for ‘x’ revolutions of energy meter disk and

calculate the Input power

Input power = X x 3600 x 0.60 Kw

C xT

0.6 = combined motor (0.75) and transmission

losses (0.8). X = No. of revolutions of energy

meter disc (say 5 Rev.)

T = Time for Energy meter revolutions disc.

in seconds C = Energy meter constant


Output power = W x Q x H Kw 1000 Where:W = Sp. Wt. of water (9810 N/m³) Q = Discharge, H = Total Head

6. Repeat the steps from 2 to 5 for various heads by regulating the delivery valve

6.6 Introduction:-

Closed Circuit Self sufficient portable package system Experimental Multi stage Centrifugal pump Test Rig is designed to study

the performance of the Multi stage Centrifugal pump. In this equipment one can study the relationship between

1. Discharge Vs Head

2. Discharge Vs Input

power 3. Discharge Vs

Efficiency

The apparatus is designed to study the performance of a multi stage Centrifugal Pump. The readings to be taken on the single stage centrifugal

pump are (1) Total Head (2) Discharge (3) Power input and (4) Efficiency. Provision has been made to measure all these and hence the complete

characteristics of the single stage Centrifugal pump in question can be studied.

First prime the pump and start the motor. While starting closing and

delivery valve and the gauge cocks. Then slowly open the delivery valve and adjust to the required total head. The total head is measured with the

help of the pressure gauge. Total head is the sum of the pressure head, Velocity head and the datum head.

Discharge is the amount of liquid the pump delivers over a definite

period of time. It is usually expressed in liter per minute. The actual discharge is measured with the help of the measuring tank. In this case

the power input into the pump cannot be measured directly. Hence the power input into the AC motor is measured with the help of the energy

meter connected in the line.

Efficiency is the relation between the power input into the pump and

the power output from the pump. The power output from the pump is directly proportional to the total head and discharge. As the power input

into the pump cannot be measured the power input into the motor only is taken into account and the overall efficiency of the pump is calculated.

If the total head (H) is measured in meters and the discharge (Q) in

liter per minute, the HQ/6120 gives the output in kW. The kilowatt input to the motor is measured with the help of the meter constant stamped on

the energy meter. The efficiency is calculated by dividing the output by input.

For a particular desired speed of the pump, the entire above variable can be studied individually, thus the complete characteristics can

be studied. 6.7 Theory:

Centrifugal pump consisting of two or more impellers the pump is

called the multistage centrifugal pump. The impeller may be mounted on

the same shaft or on different shafts. In this pump the liquid is made to

rotate in a closed chamber (volute casing) thus creating the centrifugal

action which gradually builds the pressure gradient towards outlet thus

resulting in the continuous flow, the pressure gradually builds up in

successive stages. The multistage centrifugal pumps have the following

functions;

1. To produce high heads.

2. To produce large quantities of liquids.

If a high head is required the impellers are connected in series (on the

same Shaft) while the discharge is required to be large the impellers are

connected in parallel. These pumps are more suitable for handling viscous,

turbid (muddy) liquids.

Description:-

The Test Rig mainly consists of (1) Multi stage centrifugal pump set (2) Panel Board, (3) Pressure and vacuum gauges to measure the head

(4) SS Measuring Tank to measure the discharge (5) Energy meter to measure the input to the motor and .(6) SS Sump.

MULTI STAGE CENTRIFUGAL PUMPSET: The pump set is of special design, horizontal spindle, and vertical split

case. The pump is of such a size, type & design that 1) The total head 2) Discharge and 3) Power requirements at normal speed is well suited for the experimental purposes in technical institutions.

A.C. MOTOR:

The electric motor suitable for operation on 50 HZ A.C. Supply is provided.

GAUGES: Suitable range of pressure and vacuum gauges to measure the total

head on the pump with reasonable accuracy

SS MEASURING TANK: It is provided to measure the discharge of the pump. The tank is

complete with piezo meter and scale arrangement.

PIPING SYSTEM: Suitable piping system with pipes, bends and valves are provided.

A Simple strainer valve is provided on the suction side to prevent any foreign matter entering into the pump. The gate valve is provided in the delivery side to control the head on the pump. While starting the motor always keep the valve in close position.

PANEL BOARD: The Panel Board houses all the necessary electrical items, like switch

for the above pump set and an energy meter to read the power input and it is fitted with the unit on a strong iron base with sufficient height and with provisions for foundation. INPUT POWER MEASUREMENT:

A Kilowatt-hour meter is provided to measure the power input to the motor. The energy meter constant (The Number of Revolutions per minute of the energy meter Disc) is stamped on the meter from this the input power can be easily calculated.

SS SUMP: Is provided to store sufficient water for independent circulation

through the unit for experimentation and arranged within the floor space of the main unit.



Total Head

H

Discharge

Q

INPU

T Powe

r

OUT

PUT Power

%η of

pump

m

m3/ sec

KW

KW

6.10 RESULTS:-

4. Input power = k.w

5. Output Power = k.w

6. %η of pump =

6.11 Viva Voce Questions:

1 What is priming of a pump?

Ans. Priming of a centrifugal pump is defined as the operation in which

the suction pipe, casing of the pump and a portion of the delivery pipe up to the delivery valve is completely filled from outside source with the

liquid to be raised by the pump before starting the pump. Thus the air from these parts of the pump is removed and these parts are filled with

liquid to be pumped.

2 Why it is necessary to prime a pump?

Ans. The density of air is very low, the generated head of air in terms of equivalent metre of water head is negligible and hence the water may

not be sucked from the pump. To avoid this difficulty, priming is necessary.

3 What is cavitation? Where does it occur in a centrifugal pump?

Ans. Cavitation is defined as the phenomenon of formation of vapour

bubbles of a flowing liquid in a region where the pressure of the liquid falls below its vapour pressure and sudden collapsing of these vapour

bubbles in a region of higher pressure.

4 Write the effects of cavitation?

Ans. The following are the effects of cavitations:

1. The metallic surfaces are damaged and cavities are formed on the

surfaces. 2. Due to the sudden collapse of vapour bubble, considerable noise and

vibrations are produced. 3. The efficiency of a turbine decreases.

5 What are the main parts of a centrifugal pump?

Ans. Impeller, Casting, Suction pipe with a foot valve & a strainer and Delivery

pipe

6 Distinguish between the positive and non-positive displacement pumps.

Ans. Positive displacement pump: It causes a fluid to move by trapping a fixed amount of it then forcing (displacing) that trapped volume into

the discharge pipe.

E.g. Lobe, gear, screw, vage pump etc. Non-positive displacement pump

(rotodynamic pump): It is pump in which the dynamic motion of a fluid is increased by pump action.

E.g. centrifugal, turbine, propeller etc.

7 The centrifugal pump acts as a ---- reverse of an inward radial flow reaction

turbine

8 Define pumps?

Ans. The hydraulic machines which convert the mechanical energy into

hydraulic energy are called pumps.

9 Define a centrifugal pump?

Ans. The hydraulic energy is in the form of pressure energy. If the

mechanical energy is converted, into pressure energy by means of centrifugal force acting on the fluid, the hydraulic machine is called

centrifugal pump.

10 Write the working principle of a centrifugal pump?

Ans. It works on the principle of forced vortex flow which means that when a certain mass of liquid is rotated by an external torque, the rise

in pressure head of the rotating liquid takes place.

11 Define the following terms:

(i)Suction head (ii) Delivery head (iii) Static head (iv) Manometric head

Ans. 1.Suction head— It is the vertical height of the centre line of the

centrifugal pump above the water surface in the tank or pump from which water is to be lifted. This height is also called suction lift. It is denoted by

‘hs’.

2. Delivery head -The vertical distance between the centre line of the pump and the water surface in the tank to which water is delivered is

known as delivery head. It is denoted by ‘hd’.

3. Static head-The sum of suction head and delivery head is known as static head. This is represented by ‘Hs’

4. Manometric Head -The manometric head is defined as the head against which a centrifugal pump has to work. It is denoted by ‘Hm’.

12 Write the Efficiencies of a centrifugal pump?

Ans. 1. Manometric efficiency -The ratio of the manometric head to the head imparted by the impeller to the water is known as

manometric efficiency.

2. Mechanical efficiency- The ratio of the power available at the impeller to the power at the shaft of the centrifugal pump is known as

mechanical efficiency.

3. Overall efficiency- The ratio of power output of the pump to the power input to the pump

13 Define a multistage centrifugal pump?

Ans. If a centrifugal pump consists of two or more impellers, the

pump is called a multistage centrifugal pump. The impellers may be mounted on the same shaft or on different shafts.

14 Write two important functions of a multistage centrifugal pump

Ans. A multistage pump is having the following two important functions: 1. To produce a high head 2. To discharge a large quantity of liquid

15 Define specific speed of a centrifugal pump? Ans. It is defined as the speed of a geometrically similar pump which

would deliver one cubic metre of liquid per second against a head of one metre. It is denoted by ‘Ns’.

16 Define the characteristic curves and why these curves are necessary?

Ans. Characteristic curves of centrifugal pumps are defined those

curves which are plotted from the results of a number of tests on the centrifugal pump. These curves are necessary to predict the behavior

and performance of the pump when the pump is working under different floe rate, head and speed.

17 Write the types of the characteristic curves?

Ans. 1. Main characteristic curves or Constant head curve, 2. Operating

characteristic curves or Constant speed curve, and 3. Constant efficiency or Muschel curves.

18 What is priming of centrifugal pump?

Ans. The filling of suction pipe, impeller casing and delivery pipe upto

delivery valve by the liquid from outside source before starting the pump is known as priming.

The air is removed and that portion is filled with the liquid to be pumped.

19 What is the principle of working of a Centrifugal Pump?

Ans. It is very clear that the principle used for centrifugal pump is the centrifugal force in the form of dynamic pressure which is generated by

rotary motion of one or more rotating wheels called the impellers.

20 Classify hydraulic pumps.

Ans. Pumps may be placed in one of the two general categories.

(i) Dynamic pressure pumps: centrifugal pump, jet pump, propeller, and turbine. (ii) Positive, displacement pump:

Piston plunger, gear, lab, vane, screw etc.

EXPERIMENT-7

PERFORMANCE TEST ON RECIPROCATING PUMP

7.1OBJECTIVE: To conduct a test at various heads of given reciprocating pump

finds its efficiency.

7.2 RESOURCES:


QTY

1 Pump

2 Pipe work system with all necessary control valves

3 collecting tank

4 Pressure gauge located on

suction and discharge side

7.3 PRECACTIONS

1. Operate all the controls gently

2. Never allow to rise the discharge pressure

above 40kg/cm2

3. Always use clean water for experiment

4. Before starting the pump ensure that discharge valve is opened fully

7.4 Graph:- 1. Efficiency Vs Head (Delivery) curve

Model Graph:-

Head

Efficiency

7.5 Procedure:-

1. Start the motor keeping the delivery valve fully open.

2. Note down the pressure gauge and vacuum gauge reading by adjusting

the delivery valve to require head say 0 meters. Now calculate the total head (H).


Datum head = Distance between pressure and vacuum

gauge in meters Total head (H) = Pressure Head +

Vacuum Head + Datum Head

3. Note down the time required for the rise of 10cm (i.e. 0.1m) water in the collecting tank by using stop watch. Calculate discharge using below

formula. Discharge:- The time taken to collect some ‘x’ cm of water in the collecting tank

in m³/sec.


h = rise of water level taken in meters (say 0.1m or 10cm) t = time taken for rise of water level to height ‘h’ in seconds.

4. Note down the time taken for ‘x’ revolutions of energy meter disk

and calculate the Input power

Where, 0.70= Combined motor

losses. 0.80 = Belt (or) transmission losses.

X = No. of revolutions of energy meter disc (say 5 Rev.) T = Time for Energy meter

revolutions disc. in seconds C = Energy meter constant


Where: W = Sp. Wt. of water

(9810 N/m³) Q = Discharge

H = Total Head

6. Repeat the steps from 2 to 5 for various heads by regulating the delivery valve.

Note: -- Maximum head should not exceed 2.5m (i.e. 2.5kg/sq. cm)

Check the lubricating oil SAE 40 in the crankcase of the reciprocating pump

to the required level i.e. 400ml. 7.6 Introduction:-

The Closed Circuit self sufficient portable package system

Experimental Reciprocating Pump Test Rig is designed to study the performance of theReciprocating pump at different heads. This unit has

several advantages like does not require any foundation, trench keeping in

the laboratory. Pour the lubricating oil SAE 40 in the crankcase of the reciprocating

pump to the required level once in a year. This will require about 250 cc of

oil prime the pump before starting see that the V belt are in proper tension.

Start the Motor keeping the delivery valve in fully open position. Open the

gauge cocks, and see the pressure developed by the pump. Delivery

control valve may be closed up to about 30 meters of the water head on

the delivery side. Under any circumstances the valve should not be closed

beyond 40 meters head on the delivery side. If the pressure exceeds this

valve (40 Kg/sq.cm) the cylinder head gasket joints, piston, pressure gauge

etc. would be damaged. To stop the pump set, first close the gauge

cocks. Do not close the delivery valve on the other hand it may open fully.

Then switch off the motor.

Start the pump and run it at a constant speed and the hand head may be tried, say from 10 meters to 30 meters. The discharge will be more or

less thank same depending upon the leakage past the piston, which is

dependent this on the total on the pump 6 to 8 readings can be taken

within this head range. The above procedure can be repeated and the pump tested the different heads.

Theory:

The reciprocating pump is a positive displacement pump, i.e., it

operates on the principle of actual displacement or pushing of liquid by a

piston or plunger that executes a reciprocating motion in a closely fitted

cylinder. The liquid is alternately

• Drawn from the sump and filled into suction side of the cylinder. • Led to the discharge side of the cylinder and emptied to the delivery pipe.

The piston or plunger gets its reciprocating motion (moves

backward & Forward) by means of the crank and connecting rod

mechanism. In a double acting reciprocating pump suction and delivery

strokes occurs simultaneously. A pump gives comparatively a more uniform

discharge than the single acting pump, because of the continuity of suction

and delivery strokes.

Discharge pressure = P in m

Head = H in m

Flow rate = Q m3/s

Input power = P watt

Water power (Po) = (ρgHQ) Watt

Efficiency (η) = (P/Po) x 100

7.7 Description:-

The Reciprocating Pump Test Rig mainly consists of

1) A Reciprocating Pump

2) A Single phase 2.0 HP 1440 RPM AC Motor

3) Piping system & Collecting tank

4) Input power Measuring arrangement and

5) SS Sump tank

RECIPROCATING PUMP:

The Reciprocating pump is of single acting type. The suction & delivery

size are 1"x3/2" respectively. Bore: 38 mm, Stroke: 48 mm.

MOTOR: The Motor supplied is of 2 HP 1440 RPM. It can be operated on AC 50

cycles 220/230V, through mains. A smaller HP motor can be used for normal working conditions, a higher power motor is selected to test the pump at higher speed, high pressure combinations, without over loading it.

PIPING SYSTEM:

Suitable piping system with pipes, bends valves etc. Arrangement

with cocks is, also provided for connecting pressure and vacuum gauges to the delivery and suction pipes.

A simple strainer valve is provided on the suction side to prevent any foreign matter from entering into the pump. The gate valve is provided on

the delivery side to control the Head of the pump. Note that the delivery valve should never be closed when the pump is working. While

starting the motor always keep the valve in open position. Otherwise the pump parts will be damaged.

SS COLLECTING TANK:

A Collecting tank is provided to measure the discharge water through pizeo meter arrangement. INPUT POWER MEASUREMENT:

A Kilowatt-hour meter is provided to measure the power input to the motor. The energy meter constant (The Number of Revolutions per minute of the energy meter Disc) is stamped on the meter. From this the input power can be easily calculated.

SS SUMP: A Sump is provided compactly with in the (Floor space of the main unit

to store adequate water for circulation through the unit for experimentation)

7.7 Principle:-

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 in to 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 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.



Total Head

H

Discharge

Q

INPU

T Powe

r

OUT PUT

Power

%η of pump

m

m3/ sec

KW

KW

7.10 RESULTS:-

1. Input power = k.w 2. Output Power = k.w 3. %η of pump =

7.11 Viva Voce Questions:

1 What is an air vessel?

Ans. An air vessel is a closed chamber containing compressed air in the

top portion and liquid at the bottom of the chamber.

2 What is negative slip in case of reciprocating pump?

Ans. If actual discharge is more than the theoretical discharge, the slip of the pump will become –ve. In that case, the slip of the pump is known as

negative slip.

It occurs when delivery pipe is short, suction pipe is long and pump is running at high speed.

3 What do you understand by single acting & double acting pump?

Ans. According to the water being in contact with one side or both sides of the piston:

If the water is in contact with one side of the piston, the pump is known as single acting. On the other hand, if the water is in contact with both

sides of the piston, the pump is called double acting.

4 What is the function of air vessel in a reciprocating pump?

Ans. An air vessel is fitted to the suction pipe and to the delivery pipe at a point close to the cylinder of a single-acting reciprocating pump:

i)to obtain a continuous supply of liquid at a uniform rate, ii)to save a considerable amount of work in overcoming the frictional

resistance in the suction and delivery pipes, and iii)to run the pump at a high speed without separation.

5 Define slip of a pump?

Ans. Slip of a pump is defined as the difference between the theoretical

discharge and actual discharge of the pump.

6 Define a reciprocating pump?

Ans. The mechanical energy is converted into hydraulic energy (or pressure

energy) by sucking the liquid into a cylinder in which a piston is reciprocating (moving backwards and forwards), which exerts the thrust

on the liquid and increases its hydraulic energy (pressure energy), the pump is known as reciprocating pump.

7 What are the main parts of the reciprocating pump?

Ans. 1. A cylinder with a piston, piston rod, connecting rod and a crank,

2. Suction pipe, 3. Delivery pipe, 4. Suction valve, and 5. Delivery valve.

8 Define slip of reciprocating pump?

Ans. The difference of theoretical discharge and actual discharge is known as slip

of the pump 9 How do you classify the reciprocating pumps?

Ans. 1. According to the water being in contact with one side or both sides of the piston, (i)Single acting pump (ii) Double acting pump

2. According to the number of cylinders provided.

(i)Single cylinder pump (ii) Double cylinder pump (iii) Triple cylinder

pump

10 What is the principle of working of a reciprocating pump?

Ans. In reciprocating pumps the mechanical action causes the fluid to move using one or more oscillating pistons, plungers etc. It requires a

system of suction and discharge valves to ensure that the fluid moves in a positive direction.

11 Define indicator diagram? Ans. The indicator diagram for a reciprocating pump is defined as the

graph between the pressure head in the cylinder and the distance travelled by piston from inner dead centre for one complete revolution of

the cranck.

12 Write the formula for discharge through a pump per second for a single

& double acting reciprocating pumps? Ans. (i) Discharge through a pump per second for a single acting

reciprocating pump Q=ALN/60

(ii) Discharge through a pump per second for a double acting

reciprocating pump Q=2ALN/60 Where A= Cross-sectional area of

the piston L=Length of the stroke

N=No. of revolution per second

13 What are the factors which influence the speed of

reciprocating pump? Ans. Speed of reciprocating pump is influenced by: 1. Absolute pressure inside the cylinder..

2. Cavitation produced. 3. It also affected with acceleration of piston

4. Friction in the pipes.

EXPERIMENT -8

CALIBRATION OF VENTURIMETER

8.1 OBJECTIVE :To determine the Coefficient of Discharge of Venturi meter.

8.2 RESOURCES:

S.NO Name of the

equipment

QTY

1 Venturi Meter

2 Measuring Tank

3 Sump Tank

4 Differential Manometer

5 Piping System

6 Supply Pump Set

7 Stop Watch.

8.3 Precautions:

1. All the joints should be leak proof and water tight

2. Manometer should be filled to about half the height with mercury

3. All valves on the pressure feed pipes and manometer should be closed to

prevent damage and over loading of the manometer before starting the

motor.

4. Ensure that gauge glass and meter scale assembly of the measuring tank

is fixed vertically and water tight

5. Ensure that the pump is primed before starting the motor

6. Remove the air bubbles in differential manometer by opening

air release valves 7. Take the differential manometer readings

without parallax error

8. Ensure that the electric switch does not come in contact with water

9. The water filled in the sump tank should be 2 inches below the upper end.

8.4 Model Graph: A graph between Qact vs √H

√H

Qact

8.5 Procedure:

1. Before starting the experiment, do priming of pump to remove air bubbles

by pouring water in the priming device. 2. Then open the inlet valve of the piping system of pump and Venturi meter

pipe outlet valve and close orifice meter pipe outlet valve. 3. Start the motor and open the pressure feed pipes valves to remove the air

bubbles if any. 4. Close all the valves, except upstream and downstream ball valves of pipes connected with Venturi meter.

5. Note the readings in differential manometer

6. Close the outlet valve of measuring tank and note the 10 cm raise of water using

stop watch

7. Repeat the process 3 to 4 times and note the values for different flow rates of water. 8. After conducting experiment close all the pressure feed pipe valves and

switch off the power supply.

8.6 Fig

8.7 Theory:

A Venturi meter is a device which is used for measuring the rate of flow or

discharge of fluid through a pipe. The principle of the venturimeter was first

demonstrated in 1797 by Italian Physicist G.B.Venturi(1746 - 1822), but the

principle was first applied by C. Hershel(1842 - 1930) in 1887.

The basic principle on which a venturi works is that by reducing the cross

sectional area of the flow passage, a pressure difference is created and the

measurement of the pressure difference enables the determination of the discharge

through the pipe. To avoid the possibility of flow separation and the consequent

energy loss, the divergent cone of the venturi meter is made longer with a

gradual divergence. Since the separation of flow may occur in the divergent

cone of the venturi meter, this portion is not used for discharge measurement.

Since the cross sectional area of the throat is smaller than the cross-

sectional area of the inlet section, the velocity of flow at the throat will become

greater than that at the inlet section, according to continuity equation. The

increase in the velocity of flow at the throat results in the decrease in the

pressure at this section. As such a pressure difference is developed between the

inlet section and the throat of the venturi meter. The pressure difference

between these sections can be determined by connecting a differential

manometer. The formation of vapour and air pockets in the liquid results in a

phenomenon called cavitation which is not desirable. In order to avoid cavitation to

occur, the diameter of the throat can be reduced only up to a certain limited value.

8.8 Specifications:

1. Sump tank size: 0.3 m x 0.45 m x 0.94 m S.S. Tank

2. Measuring tank size: 0.3 m x 0.3 m x 0.5 m S.S. Tank

3. Differential Manometer: 1.0 m range with 1mm scale graduations

4. Pipe size: 25 mm

5. Venturi meter inlet diameter (d1 ) : 25 mm

6. Venturi throat diameter (d 2 ):14 mm

7. Area ratio (a 2 /a1 ) m : 0.35

8. Supply pump set : Pump is 25 x 25 mm2 size,

Centrifugal Monoset pump with single

phase, 2 Pole,

220V, 50Hz, ½ HP, 2780 RPM, AC Supply

8.9 Description of Apparatus: It is a closed circuit water re-circulation system

consisting of sump tank, measuring tank, centrifugal monoset pump, one pipeline

fitted with venturi meter. 1. Venturi Meter: Venturi meter is a device which is used for measuring the rate

of flow of fluid through a pipe which consists of hose collars. Venturi meter consists

of

a. An inlet section followed by a convergent cone

b. A cylindrical throat c. A gradually divergent cone

a. Inlet Section : It is of the same diameter as that of the pipe which is followed by a

Convergent cone.

Convergent cone : It is a short pipe which tapers from the original size of the pipe to

that of the throat of the venturi meter

b. Throat : It is a short parallel sided tube having its cross-sectional area

smaller than that of the pipe.

c. Divergent Cone : It is a gradually diverging pipe with its cross-sectional area increasing from that of the throat to the original size of the pipe.

At the Inlet section and throat, pressure taps are provided through pressure rings.

1. Total included angle of convergent cone: 210 + 10

2. Length parallel to the axis of convergent cone : 2.7 (D-d) i. D = Diameter of the inlet section

ii. d = Diameter of the throat

3. Length of throat: d

4. Total included angle of divergent cone : 5 0 to 150 (preferably about 60)

Diameter of throat may vary from 1/3

to 3/4

of the pipe diameter and more

commonly the diameter of the throat is kept equal to half of pipe diameter.

2. Piping System: Consist of a pipe of size 25mm with separate control valve and

mounted on a suitable strong iron stand. Separate upstream and downstream

pressure feed pipes are provided. There are pressure taping valves which are ball

valves and there are four manometer ball valves.

3. Measuring Tank: It is a stainless steel (S.S) Tank with gauge glass, a scale

arrangement for quick and easy measurements. A ball valve which is outlet valve of

measuring tank is provided to empty the tank. 4. Sump Tank: It is also a S.S. tank to store sufficient fluid for experimentation

and arranged within the floor space of main unit. The sump should be filled with

fresh water leaving 25 mm space at the top.

5. Differential Manometer: It is used to measure the differential head produced by venturi meter.

6. Pumpset: It is used to pump water from sump tank to measuring tank through pipe.

8.10 Formulae:

Actual discharge:

Actual discharge (Qact ) = A.R m3/s

A = Area of measuring (or) collecting tank = 0.3 x 0.3 m2

R = Rise of water level taken in meters (say 0.1 m or 10 cm) t = time taken for rise of water level to rise ‘R’ in ‘t’ seconds

The actual discharge is measured with the help of measuring tank and by noting

the time for definite raise of water level in the tank

t

Theoretical discharge:

Theoretical discharge (Q th ) =

Where

h =(h1-h2)

h1 -h 2 = Difference in Manometric liquid in cm

Sm = Specific gravity of Manometric liquid

S 2 = Specific gravity of flowing liquid

g = Acceleration due to gravity (9.81 m/s 2

)

a1 = Inlet area of Venturi meter in m

a 2 = Area of throat in m 2

Coefficient of discharge:

Coefficient of discharge(C d ) = = ActualDischarge

TheoriticalDischarge

8.10 Table of Readings:

S.NO

Manometer reading

cm of hg

Manometer head

h cm

Time for (10

cm) rise of

water level t

in Sec.

h1

h 2

h m

Table of Calculations:

S.NO

Actual Discharge

Qact

Theoretical

Discharge

Qth (m3/sec)

Qth (m3/sec)

Coefficient of

Discharge

Cd = Qact / Qth

8.11 Sample Calculations:

Area of inlet (a1)=

d1 = Venturi inlet diameter = 25 mm = 25x10-3 m

Area of inlet (a1)=

d2 = Throat diameter = 14 mm = 14x10-3 m

Manometer head h in m

Theoretical discharge of Venturi meter in m3/sec Time for 100 mm rise in sec (t) =

Actual discharge of Venturi meter = m3/sec

Coefficient of discharge of Venturimeter (C d ) =

8.12 Results:

Actual discharge of Venturi meter (Q act )= m3/sec

Theoritical discharge of Venturi meter (Q th )= m3/sec

Coefficient of discharge(Cd)

8.13Viva Questions:

1. Who demonstrated the principle of Venturi meter first? A. The Principle of Venturi meter was first demonstrated in 1797 by Italian

Physicist G.B. Venturi (1746 - 1822).

2. Who applied Venturi meter principle? A. C. Herschel (1842-1930) applied Venturi meter principle in 1887.

3. What is the basic principle of venturi meter? A. The basic principle on which a venturi meter works is that by reducing the

cross-sectional area of the flow passage, a pressure difference is created and

the measurement of the pressure difference enables the determination of the discharge through the pipe.

4. What are the parts of Venturi meter? A. a. An inlet section followed by a

convergent cone b. A Cylindrical throat

c. A gradually divergent cone

5. What is convergent cone? A. It is a short pipe which tapers from the original size of the pipe to that of the throat of the venturi

meter

6. What is throat of Venturi meter? A. The throat of the Venturi meter is a short parallel sided tube having its cross-sectional area smaller

than that of the pipe.

7. What is divergent cone? A. It is a gradually diverging pipe with its cross-sectional area increasing from that of

the throat to the

original size of the pipe.

8. Where pressure taps are

provided? A. At the inlet section

and throat.

9. What is the total included angle of convergent cone of Venturi meter? A. 210 + 1

51 10. What is the length of the

convergent cone? A. 2.7 (D-d)

D = Diameter of the inlet section d = Diameter of the throat

11. What is the included angle of divergent cone? A. 50 to 150 (preferably about 60)

12. Which part is smaller, convergent cone or divergent cone? Why? A. Convergent cone is smaller. To avoid the possibility of flow separation and the

consequent energy loss, the divergent cone of the venturi meter is made longer

with a gradual divergence.

13. Where separation of flow occurs? A. In Divergent cone

of Venturi meter

14. Which portion is not used for discharge measurement? A. Divergent cone

15. Which cross-sectional area is smaller than cross sectional area

of inlet section? A. Throat

16. Where velocity of flow

greater? A. Throat

17. Where pressure is low in

Venturi meter? A. Throat

18. How pressure difference is

determined? A. By connecting a

differential manometer

19. Between which sections the pressure difference can

be determined? A. Inlet section and Throat

20. What we should do for getting greater accuracy in the measurement of the pressure difference?

A. The cross sectional area of the throat should be reduced so that the pressure at

throat is very much reduced.

21. What is cavitation? A. The formation of the vapour and air pockets in the liquid ultimately results in a

phenomenon called Cavitation.

22. What is value of diameter of throat? A. The diameter of throat may very from 1/3 to ¾ of the pipe diameter and more commonly the

diameter of the throat is kept equal to ½ of the pipe diameter.

23. What should be done to avoid cavitation?

A. The diameter of throat should be reduced only up to a certain limited value

24. Write the formula for actual discharge

25. Write the formula for theoretical discharge.

A. Q th

=

a1a2 2gh

a1 a2

26. Write the co-efficient o f discharge

27. Venturi meter based on which

principles? A. Bemoulli’s equation.

28. What is the value of C d for Venturi meter?

A. It is less than 1 and it may be between 0.95 and 0.99.

29. What are the applications of Bernoulli’s equation?

A. Venturi meter, Orifice meter, Pitot tube, Nozzle meter

30. What is Venturi meter? And what is its use? A. Venturi meter is a device which is used for measuring the rate of flow of fluid

through a pipe

t

2 2

EXPERIMENT-9

CALIBRATION OF ORIFICEMETER

9.1OBJECTIVE : To determine the Coefficient of Discharge of Orifice meter.

9.2RESOURCES:


QTY

1 Orifice Meter

2 Measuring Tank

3 Sump Tank


5 Piping System

6 Supply Pump set

7 Stop Watch. 9.3 Precautions:

1. All the joints should be leak proof and water tight 2. Manometer should be filled to about half the height with mercury 3. All valves on the pressure feed pipes and manometer should be closed to

prevent damage and over loading of the manometer before starting the motor.

4. Ensure that gauge glass and meter scale assembly of the measuring tank

is fixed vertically and water tight 5. Ensure that the pump is primed before starting the motor 6. Remove the air bubbles in differential manometer by opening air release valve 7. Take the differential manometer readings without parallax error 8. Ensure that the electric switch does not come in contact with water 9. The water filled in the sump tank should be 2 inches below the upper end.

9.4 Graph: A graph between Qact vs √H

Model Graph: 9.5 Procedure:

1. Before starting the experiment, do priming of pump to remove air bubbles by pouring water in the priming device.

2. Then open the inlet valve of the piping system of pump and orifice meter outlet valve and close venturimeter pipe outlet valve.

3. Start the motor and open the pressure feed pipe valves to remove the air bubbles if

any. 4. Close all the valves, except upstream and downstream ball valves of pipes

connected with orifice meter 5. Note the readings in differential manometer 6. Close the outlet valve of measuring tank and note the 100 mm raise of water using stop watch. 7. Repeat the process 3 to 4 times and note the values for different flow rates of water. 8. After conducting experiment close all the pressure feed pipe valves and switch off the power supply. 9.6 Fig:

9.7 Description of Apparatus: It is a closed circuit water re-circulation

system consisting of Sump tank, Measuring tank, Centrifugal Monoset pump, one

pipeline fitted with Orifice meter.

1. Orifice Meter: It is a cheaper arrangement for discharge measurement

through pipes and its installations requires a smaller length as compared with

venturi meter .It consists of a flat circular plate with a circular hole called orifice

which is concentric with the pipe axis. The thickness of the plate t is less than or

equal to 0.05 times the diameter of the pipe.

From the upstream face of the plate the edge of the orifice is made flat for

a thickness t 1 less than or equal to 0.02 times the diameter of the pipe and for

the remaining thickness of the plate it is bevelled with the bevel angel lying

between 30 0 to 45 0 . If the plate thickness t is equal to t 1 , then no bevelling is

done for the edge of the orifice. The diameter of the orifice may vary from 0.2 to

0.85 times the pipe diameter, but generally the orifice diameter is kept as 0.5

times the pipe diameter. Two pressure taps are provided, one on upstream side of

the orifice plate, and the other on the downstream side of the orifice plate. The

upstream pressure tap is located at a distance of 0.9 to 1.1 times the pipe

diameter from the orifice plate .The position of the downstream pressure tap,

depends on the ratio of the orifice diameter and pipe diameter.

2. Piping System: Consist of a pipe of size 25mm with separate control valve and

mounted on a suitable strong iron stand. Separate upstream and downstream

pressure feed pipes are provided. There are pressure taping valves which are ball

valves and there are four manometer ball valves.

3. Measuring Tank: It is a stainless steel (S.S) Tank with gauge glass, a scale


measuring tank is provided to empty the tank. 4. Sump Tank: It is also S.S. tank to store sufficient fluid for experimentation

and arranged within the floor space of main unit. The sump should be filled with

fresh water leaving 25 mm space at the top.

5. Differential Manometer: It is used to measure the differential head produced by Venturi meter.

6. Pump set: It is used to pump water from sump tank to measuring tank through pipe.

9.8 Theory:

An orifice meter is another simple device used for measuring the

discharge through pipes. Orifice meter also works on the same principle as that

of venturi meter i.e, by reducing the cross sectional area of the flow passage a

pressure difference between the two sections is developed and the measurement of

the pressure difference enables the determination of the discharge through the

pipe. On the downstream side the pressure tap is provided quite close to the

orifice plate at the section where the converging jet of the fluid has almost the

smallest cross sectional area( which is known as vena contracta) resulting in

almost the maximum velocity of the flow and consequently minimum pressure

at this section. Therefore the maximum possible pressure difference exists

between the sections 1 and 2, which is measured by connecting a differential

manometer. The jet of the fluid coming out of the orifice meter gradually expands

from the vena contracta to again fill the pipe. Since in the case an orifice meter

an abrupt change in the cross sectional area of the flow passage is provided and

there being no gradual change in the cross sectional area of the flow passage as in

the case of a venturi meter, there is a greater loss of energy in an orifice meter

than in a venturi meter .

9.9Specifications:

1. Sump tank size: 0.3 m x 0.45 m x 0.95 m S.S. Tank

2. Measuring tank size: 0.3 m x 0.3 m x 0.5 m S.S. Tank

3. Differential Manometer: 1.0 m range with 1mm scale graduations 4. Supply pump set: Pump is 25 x 25 mm2 size, Centrifugal moonset pump Single phase, 2 pole, 220V, 50Hz, ½ HP, 2780 RPM, AC 5. Pipe size: 25 mm 6. Orifice meter inlet diameter(d1 ): 25 mm

7. Orifice meter diameter(d 2 ) : 13 mm

8. Area ratio (a 2 /a1 ) m : 0.45



S.NO Actual Discharge Qact

m3/sec

Theoritical Discharge Qth

m3/sec Coefficient of discharge(C d )

9.11 Formulae:

Actual discharge:

Actual discharge (Q act ) = m3/s

A = Area of measuring (or) collecting tank = 0.3 x 0.3 m2

R = Rise of water level taken in meters (say 0.1 m or 10 cm)

t = time taken for rise of water level to rise ‘R’ in ‘t’ seconds

The actual discharge is measured with the help of measuring tank and by noting

the time for definite rise of water level in the tank

S.No Manometer reading cm of Hg

Manometer head( h) m

Time for 10cm rise of water

rise of water

h1 h2 hm

Theoretical discharge (Q th ):

Theoretical discharge (Q th ) =

Where

h =(h1-h2)

h1 -h 2 = Difference in Manometric liquid in cm

Sm = Specific gravity of Manometric liquid

S 2 = Specific gravity of flowing liquid

g = Acceleration due to gravity (9.81 m/s 2

)

a1 = Inlet area of orificemeter in m

a 2 = Area of orifice in m 2

Coefficient of discharge:

Coefficient of discharge(C d )

ActualDischarge =

TheoriticalDischarge

9.12 Sample Calculations:

Area of inlet (a1)=

d1 = Venturi inlet diameter = 25 mm = 25x10-3 m

Area of inlet (a1)=

d2 = Throat diameter = 13 mm = 13x10-3 m

Manometer head h in m =

Theoretical discharge of Venturi meter in

Time for 100 mm rise in sec (t) =

Actual discharge of Venturi meter =

Coefficient of discharge of Orifice

meter (C d ) =

9.13 Results:

Actual discharge of Orifice meter (Q act ) = m3/sec

Theoretical discharge of Orifice meter (Q th ) = m3/sec

Coefficient of discharge of Orifice meter (C d ) =

9.14 Viva Questions:

1. For which one, the coefficient of discharge is smaller, venturimeter

or Orificemeter? A. Orifice meter

2. What is the reason for smaller value of C d ?

A. There are no gradual converging and diverging flow passages as in the case of

venturimeter which results in a greater loss of energy and consequent reduction

ofthe coefficient of discharge for an orifice meter

3. What is Orifice meter?

A. An orifice meter is another simple device used for measuring the discharge through pipes.

4. What is the principle of Orifice meter? A. Orifice meter also works on the same principle as that of venturi meter i.e, by reducing the cross

sectional area of the flow passage a pressure difference between the two sections

is developed and the measurement of the pressure difference enables the

determination of the discharge through the pipe.

5. For discharge measurement through pipes which is having cheaper

arrangement and whose installation requires a smaller length? A. Orifice meter

6. What are the parts of Orifice

meter? A. Flat circular plate with

a circular hole

7. What is the thickness of the plate t? A. t 0.05d where d= diameter of the pipe

8. What is the range of bevel angle in orifice meter? A. 300 to 450 (preferably 450 )

9. What is the diameter of the orifice? A. It may vary from 0.2 to 0.85 times the pipe diameter, but generally the orifice

diameter is kept as 0.5

times pipe diameter

10. Where two pressure taps are provided?

A. One on upstream side of the orifice plate and the other on downstream side of the orifice plate.

11. Where upstream pressure tap is located?

A. It is located at a distance of 0.9 to 1.1 times the pipe diameter from the orifice plate.

12. Which diameter is less, orifice

or pipe? A. Orifice meter

13. What is vena contracta?

A. Smallest cross sectional area

14. At which section on the downstream side the pressure tap is provided quite close to

orifice plate? A. At the section where the converging jet of fluid has almost the smallest cross

sectional area (which is

known as vena contracta)

15. Where the velocity of flow is maximum and pressure

is minimum? A. At vena contracta

16. Maximum possible pressure difference that exists between upstream side of

the orifice plate and downstream side of the orifice plate is measured by means

of what? A. Differential manometer

17. Where there is a greater loss of energy, whether in venturi meter

or in orifice meter? A. In orifice meter

18. Why there is a greater loss of energy in orifice meter?

A. Because there is an abrupt change in the cross-sectional area of flow passage

19. What is value of c d ?

A. It is the range of 0.6 to 0.68

20. What is the manometer

liquid? A. Mercury

21. When an orifice is called large orifice? A. When head of liquid from the center of the orifice is less than 5 times the depth of

orifice

22. On what the position of downstream pressure tap depends? A. It depends on the ratio of the orifice diameter and the pipe diameter.

EXPERIMENT-10

DETERMINATION OF FRICTION FACTOR FOR A GIVEN PIPE LINE

10.1 OBJECTIVE: To measure the frictional losses in pipes of different sizes.

10.2RESOURCES:


QTY

1 Piping system

2 Sump Tank

3 Measuring Tank


5 Pump Set

6 Stop Watch

10.3 Precautions:


2. While doing the experiment on a particular pipe keep the other

pipe line closed 3. Take the differential manometer readings

without parallax error


5. Remove air bubbles in differential manometer by opening air release valve

6. Ensure that opening and closing of manometer valves should be done

carefully to avoid leakage of mercury

7. Check that gauge glass and meter scale assembly of the measuring

tank is fixed vertically and water tight


9. Ensure that all valves on the pressure feed pipes and manometer

should be closed to prevent damage and over loading of the manometer

10. All the joints should be leak proof and water tight.

11. The water filled in the sump tank should be 2” below the upper end

10.4 Graph: A graph between V2 on X-axis and hf on Y-axis is drawn

Model Graph:

hf

V2

10.5 Procedure:

1. Before starting the experiment, do priming of the pump to remove air bubbles

by pouring water into the priming device. 2. Open the inlet valve in the piping systems of the pump and outlet valve of

one of the 3 pipes and remaining 2 valves will be in closed condition 3. Start the motor and open the upstream pressure feed pipe valves and

downstream pressure feed pipe valves of the concerned pipe 4. Remove the air bubbles by opening the pressure feed pipe valves if any. 5. Note down the manometer reading 6. Close the outlet valve of measuring tank and measure the time taken for 10

cm raise in water level by measuring tank. 7. Repeat the procedure 2 to 3 times for various flow rates of water 8. Same procedure is adopted for 2 other pipes by opening the concerned valves

and remaining valves in closed condition. 9. Note the values and do the calculation to find out the frictional loss.

10.6 Description of apparatus:

1. Piping system: Consists of a set of 2G.I pipes and 1 S.S pipes of size 20mm,

12.7mm and 20mm and length 1 m between pressure tapings with separate

flow control valves. Separate upstream

and downstream pressure feed pipes are provided for the measurement of

pressure heads with control situated at common place for easy operation.

2. Sump tank: It is S.S. tank to store sufficient fluid for experimentation and

arranged within the floor space of main unit. The sump should be filled with fresh

water having 25 mm space at the top. 3. Measuring tank: It is also a S.S tank with gauge glass, a scale

arrangement for quick and easy measurements. A ball valve which is outlet valve

of measuring tank is provided to empty the tank.

4. Differential manometer: It is used to measure the differential head produced by piping system.

5. Pump set: It is used to pump water from sump tank to measuring tank through pipe. 10.7 Theory:

A pipe is a closed conduit which is used for carrying fluids under pressure.

Pipes are commonly circular section. As the pipes carry fluids under pressure, the

pipes always run full.

The fluid flowing in a pipe is always subjected to resistance due to shear forces between fluid particles and the boundary walls of the pipe and between the fluid particles themselves resulting from the viscosity of the fluid. The resistance to the flow

of fluid is, in general known as frictional resistance. Since certain amount of energy possessed by the flowing fluid will be consumed in overcoming this resistance to the

flow, there will always be some loss of energy in the direction of flow, which however depends on the type of flow, W.froude conducted a series of experiments to investigate frictional resistance offered to the flowing water by different surfaces

h f =4FLV2/2gd is Darcy Weisbach equation

Which is commonly used for computing the loss of head due to friction of pies.

Here is f friction factor. In order to determine the loss of head due to friction

correctly, it is essential to estimate the value of the factor f correctly when a fluid

flows through a pipe, certain resistance is offered to the flowing fluid, which

results in causing a loss of energy. The various energy losses in pies may be

classified as

i) major losses

ii) minor losses

The major loss of energy, as a fluid of flows through a pipe, is caused by friction. It

may be computed by Darcy-Weisbach equation. The loss of energy due to friction

is classified as a major loss because in the case of long pipelines it is usually much

more than the loss of energy Incurred by other causes.

10.8 Specifications:

1. Sump tank size

2. Measuring Tank

Size

: 0.95 m x 0.45 m x 0.3 m S.S. tank

: 0.3 m x 0.3m x 0.5 m S.S. Tank

3. Differential

Manometer

4. No. of pipes

5. Piping system sizes

6. Pressure taping distance

7. Pump set

: 1 m range with 1mm scale of graduation

: 1S.S, 2 Galvanized Iron(GI) pipes

: 20 mm, 20mm, 12.7mm

: 0.1 m : Pump is 25x25mm2 size, centrifugal, moonset

:pump with single phase, 2pole, 220V, 1/2HP, 50

Hz, 2880 rpm, AC supply.


Type

of Pipe

Diamete

r of the Pipe

‘d’

Area of Pipe A

m2

Manomet

er

reading

Water

collected

i

n collecting

tank ‘R’

Time for (10

cm) rise of

water level

t in Sec.

h1

h2

hm

mm

m

cm of Hg

cm

m

Sec


Loss Of

Head

(12.6 x hm)

100

‘hf’

Actual

Dischar

ge

Qact = A R/t

Theoretical Velocity

V = a

V 2

Friction Factor

f

m

m3/sec

m3/sec

67

Q/

10.10 Formulae:

The actual loss of head is determined from the manometer readings. The frictional

loss of head pipes is given by the following formula

h f = 4fLV 2

2gD

f = Coefficient of friction for the pipe (frictional factor)

L= Distance between two sections from which loss of head is measured (3 m)

V = Average velocity of flow =

Q = AR/T= Discharge in m3/s

a=Area of the pipe

A=Area of collecting tank

g = acceleration due to gravity

D = Pipe diameter in meters Sample calculations:

Actual discharge in m3/s =

Area of the pipe= m2

Average velocity of water in the pipe v = m/sec Frictional loss of head in pipe h

f =

Frictional factor f =

10.11 Results:

Coefficient of loss of head h f =

Friction factor f =


1. What is pipe?

A. A pipe is a closed circuit which is used for carrying fluids under pressure

2. The fluid flowing by a pie is always subjected to what? A. It is subjected to resistance due to shear forces between fluid particles and the

boundary walls of the

pipe and between the fluid articles themselves resulting from the viscosity of the fluid

3. What is frictional resistance?

A. The resistance to the flow of fluid is frictional resistance. 4. In overcoming the frictional resistance what is consumed?

A. Certain amount of energy possessed by the flowing fluid will be consumed

5. What will be there in the direction of flow and it depends on what?

A. There will be some loss of energy in the direction of flow and depends on the type of

flow.

6. What are the types of flow of fluid

in a pipe? A. Laminar, turbulent

7. On what the frictional resistance offered to the flow

depends on? A. Type of flow

8. What is Darcy-Weisbach equation?

A. h f =

4fLV 2

2gD

EXPERIMENT-11

Determination Of Loss Of Head Due To Sudden Contraction In a Pipe Line

11.1 OBJECTIVE: To determine the coefficient of loss of head due to sudden contraction

11.2 RESOURCES:

S.NO Name of the

equipment

QTY

1 Piping system

2 Sump Tank

3 Measuring Tank


5 Pump Set

6 Stop Watch

11.3 Precautions:


2. While doing the experiment on a particular pipe keep the other

pipe line closed

3. Take the differential manometer readings without parallax

error


5. Remove air bubbles in differential manometer by opening air release valve

6. Ensure that opening and closing of manometer valves should be done

carefully to avoid leakage of mercury

7. Check that gauge glass and meter scale assembly of the measuring tank

is fixed vertically and water tight


9. Ensure that all valves on the pressure feed pipes and manometer should

be closed to prevent damage and over loading of the manometer

10. All the joints should be leak proof and water tight.

11. The water filled in the sump tank should be 2” below the upper end

11.4 Procedure:

1) Start the motor keeping the delivery valve close. Make sure that the ball valve is fully open which is at the collecting tank

2) Slowly open the cocks which are fitted at sudden contraction end and make sure that manometer is free from air bubbles

3) Make sure while taking the readings, that the manometer is properly primed. Priming is the operation of removing the air bubbles from the pipes. Note down the loss of head “hc” from the manometer scale.

4) Note down the time required for the rise of 10 cm (i.e 0.1 m) water in the collecting tank by using stopwatch. Calculate the discharge using below formula.

Discharge: The time taken to collect some ‘X’ cm of water in the collecting tank in

m3/sec

Q = AR

Where A = Area of measuring (or) collecting tank = 0.3 x 0.3 m2

R = Rise of water level taken in meters (say 0.1 m or 10 cm)

t = time taken for rise of water level to rise ‘R’ in‘t’ seconds

5) Calculate the velocity of the jet by following formula

V = Discharge / Area of pipe = Q / A m/sec Where

A = Cross sectional area of the pipe = Π / 4 * d2

d = diameter of the pipe

6) Calculate the coefficient of contraction for the given pipe by

hc = v2 / 2g * K

Where hc = loss of head due to sudden contraction = (h1-h2) * 12.6/100 m

K = co-efficient for loss of head in contraction = [1/Cc - 1]2

V = Average Velocity of flow in m/sec

7) Repeat the steps 2 to 6 for different sets of readings by regulating the discharge valve.

t


1. Piping system: piping system of size 25 mm diameter and 12.5 mm with a flow control valve.

2. Sump tank: It is S.S. tank to store sufficient fluid for experimentation and


water having 25 mm space at the top. 3. Measuring tank: It is also a S.S tank with gauge glass, a scale

arrangement for quick and easy measurements. A ball valve which is outlet valve

of measuring tank is provided to empty the tank.

4. Differential manometer: It is used to measure the differential head produced by

piping system.

5. Pump set: It is used to pump water from sump tank to measuring tank through pipe. 11.6 Specifications:

1. Sump tank size: 0.9 m x 0.45 m x 0.3 m S.S. tank

2. Measuring Tank Size: 0.6 m x 0.3m x 0.3 m S.S. Tank

3. Differential Manometer: 1 m range with 1mm scale of graduation

4. No. of pipes: 2 Galvanized Iron(GI)

5. Piping system sizes: 25 mm,12.5mm

6. Pressure taping distance: 0.5 m

7. Pump set: Pump is 25x25mm2 size, centrifugal, moonset

pump with single phase, 2pole, 220V, 1/2HP, 50

Hz, 2880 rpm, AC supply.


Type of Pip

e

Diameter of the Pipe

‘d’

Area of Pipe A

m2

Manomet

er

reading

Water

collectedin

collecting

tank ‘R’

Time for (10

cm) rise of

water level

t in Sec.

h1

h2

hm

mm

m

cm of Hg

cm

m

Sec


Actual

Dischar

ge

Qact = A R/t

Theoretical Velocity

V = Q a

Coefficient of friction

hc

Coefficient of

contraction

Cc

m3/sec

m/sec

m

11.7 Sample calculations: Discharge= AR

t

Velocity= Discharge / Area of pipe = Q / A m/sec

Coefficient of contraction= hc = v2 / 2g * K

11.8 Results:

Loss of head due to sudden contraction hc =

Coefficient of Contraction Cc =


1. Write the classification of various

energy losses. A. Major losses, minor

losses

2. What causes major loss of

energy? A. Friction

3. Major loss of energy computed by which

equation? A. Darcy-Weisbach equation

4. What is the reason for the classification of loss of energy due to friction as major loss?

A. In the case of long pipelines it is usually much more than the loss of energy incurred by other causes

5. Due to what the minor losses of energy are caused?

A. Due to change in the velocity of flowing fluid (either by magnitude or direction)

6. Why these are called minor losses? A. In case of long pipes these losses are usually quite small as compared with the loss

of energy due to

friction and hence these are termed. Minor losses which may be neglected without

serious error.

7. In where minor losses outweigh the

friction loss? A. In Short pipes 8. Write some minor losses which may be caused due to the

change of velocity. A. Loss of energy due to sudden enlargement

Loss of energy due to sudden contraction

Loss of energy at entrance to a pipe

Loss of energy at the exit from a pipe

Loss of energy due to gradual contraction or enlargement

Loss of energy in bends

Loss of energy in various pipe fit

EXPERIMENT-12

VERIFICATION OF BERNOULLI’S EQUATION

12.1 OBJECTIVE: To prove that the total head at any point along the flow is same

i.e, datum head + pressure head + velocity head is constant along the flow

or

+ + = + +

12.2 RESOURCES:


QTY

1 Bernoulli’s apparatus which consists of supply and

receiving chambers with scales and glass tubes

2 Piezometer glass tubes

3 Measuring tank (collecting tank)


5 Supply pump set

6 Stop Watch

12.3 Precautions:

1. Be careful to avoid leakage of the piezometer tubes

2. The water filled in the sump tank should be 2 inches below

the upper end

3. Ensure that the electric switch does not come in contact

with water

4. Ensure that the water level is constant in the supply tank during the experiment

5. Check that the gauge glass and meter scale assembly of the measuring

tank is fixed vertically and water tight.

6. Ensure that the pump is primed before

starting the motor.

7. All joints should be leak proof and water tight

12.4 Procedure:

1. Before starting the experiment, do priming of the pump to remove the air bubbles. 2. Open the inlet valve of the piping system of the pump. 3. Open the outlet valve of the piezometer tube. 4. Start the motor and keep the water level constant in the supply tank by

operating various valves. 5. Then note down the pressure head from the piezometer scale directly 6. Close the outlet valve of the mercury tank and note down the time for 100

mm raise of water level note down the valves for pressure head, velocity head for different areas of piezometer and calculate the total head.

12.5 Fig:


There are supply and receiving chambers and interlinking experimental sides

made out of perspex sheets for the purpose of observing the flow. The interlinking

duct is smoothly varying in cross section so that the velocity of flow changes

gradually for the purpose of experiments with minimum friction loss

and loss due to turbulence. Piezometer glass tubes are provided at suitable

intervals along the duct for the measurement of pressure head at various points. A

flow control valve is provided at the exit of the receiving chamber for adjusting

and keeping different flow rates through the apparatus. A collecting tank

(receiving chamber) is provided for the measurement of rate of flow. The

apparatus is kept in the spirit level position horizontally by means of adjusting the

screw arrangement provided at the bottom of the sump.

Measuring Tank: It is a stainless steel (S.S) Tank with gauge glass, a scale


measuring tank is provided to empty the tank. Sump Tank: It is also S.S. tank to store sufficient fluid for experimentation and


water leaving 25 mm space at the top.

Pump set: It is used to pump water from sump tank to measuring tank through pipe. 12.7 Theory:

The Bernoullis equation is

2

w +

2g +z = c

Which is applicable for steady, irrotational flow of incompressible fluids

P= pressure

W= ρg=specificweight

V= velocity at any point

g=gravitational acceleration

ρ= mass density

w = pressure head or static head

2

2g = velocity head or kinetic head

Z = potential head or datum head

C= arbitrary constant

The sum of pressure head, velocity head and the potential head is known as the

total head or the total energy per unit weight of the fluid. Bernoullis equation

states that in a steady irrotational flow of an incompressible fluid the total energy

at any point is constant.

p v

p

v

If Bernoulli’s equation is applied between any two points in a steady

irrotational flow of an incompressible fluid, then we get

\

Where the different terms with subscripts 1 and 2 correspond to the two points

considered.The sum of the pressure head and the potential head ( w

+ z ) is termed as

piezometric head. Each term represent the energy permit weight of the flowing fluid. The energy per unit weight of the fluid is expressed as N.m/N that is, it has a dimension of length and therefore it is known as head. 12.8 Specifications:

1. Sump tank size : 1.25 m x 0.3m x 0.3m S.S. tank

2. Measuring Tank size : 25mm x 25 mm

3. Pump size

4. Supply pump set: Pump is centrifugal manometer pump with single phase, 2

pole, 220V, 50 Hz, ½ Hp, 2880 RPM, AC supply

p

12.9 Observations Table:

Main tube pressure head= cm= m Reading no.

Piezometer reading

P1 P2 P3 P4 P5 P6 P7 Pressure head

cm

Pressure head p/w (m)

Velocity head-v2/2g (m)

Datumn head-Z (m)

Total head(m)

Table of calculation:

12.10 Formulae:

Actual discharge:

Actual discharge (m3 /s) = Q =

AR/t m3/S

A= Area of measuring tank = 0.3 x 0.3m2

R = Difference in levels of water in measuring tank in m

T = time in seconds

Time collected for 10cm rise of water

Discharge Q

Velocity (m/sec)

(sec) (m3/sec) 1 2 3 4 5 6 7

Velocity = Q/a

a= cross sectional area of duct at various intervals a1=a7=0.05x0.04m2 a2=a6=0.05x0.035m2 a3=a5=0.05x0.025m2 a4=0.05x0.02m2 a

Total head: Total head=(p/w)+(v2/2g)+z

p

w

= Piezometer reading pressure head

2

2g = velocity head

Z = datum head

12.11 Result:

The total head at any point along the flow is same.

v


1. What is Bernoulli’s

2equation?

A. w

+ 2g

+z = Constant

2. What is w

?

A. Pressure energy per unit weight of fluid or pressure head or static head.

2

3. What is 2g

?

A. Kinetic energy per unit weight or kinetic head or velocity head

4. What is z?

A. Potential energy per unit weight or potential head or datum head

5. What are the assumptions of Bernoulli’s

equation? A. 1) The fluid is ideal (i.e,

viscosity is zero) 2) The flow is steady

3) The flow is incompressible

4) The flow is irrotational

6. What Bernoulli’s equation states? A. It states that in a steady, ideal, irrotational flow of an incompressible fluid, the

total energy at any point of the fluid in constant

7. For which type of fluids Bernoulli’s equation is

applicable? A. For steady, irrotational flow of

incompressible fluids

8. What is total head?

A. Sum of pressure head, velocity head, and potential head is known as total head

p v

p

v

9. If Bernoulli’s equation is applicable between two points what is the

equation of Bernoulli? 2 2

A. w

+ 2g

+z1 = w

+ 2g

+z2

10. What is Piezometric head?

A. Sum of pressure head and potential head

11. In Bernoulli’s equation each term represents what? A. The energy per unit weight of the flowing fluid.

12. Why each term is called head?

A. The energy per unit weight of the fluid is expressed as Nm/N that is it has a

dimension of length and therefore it is known as head

13. What is viscosity?

A. It is the property of fluid which offers resistance to the movement of one layer

of fluid over another adjacent layer of fluid.

p 1 p 2 v v 1 2

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