ARYANET INSTITUTE OF TECHNOLOGY, PALAKKAD-678592

(Affiliated university of Calicut, Approved by AICTE)(Velikkad P.O Mundur, Palakkad-678592)

DEPARTMENT OF MECHANICAL ENGINEERING

LABORATORY MANUAL

FLUID MECHANICS & MACHINERY LAB

Exp No: 1 CALIBRATION OF VENTURIMETER

AIM: To Calibrate the given Venturimeter setup and determine the coefficient of discharge.

APPARATUS: Venturimeter Experimental setup, Stopwatch.

PRINCIPLE :

Venturimeter is a device is used for the measurement of flow rate particularly in large sized pipes and for large flow rates. It consists of a cylindrical entrance section followed by a converging conical section which is flowed by a throat. The throat is followed by a diverging section. The converging takes place at an angle of 210 and the velocity of fluid increase as it passes through the converging section and correspondingly the static pressure falls. At the throat, the velocity is maximum and pressure is minimum. The throat diameter is usually between 0.5 to0.25 of the inlet diameter. Length of the throat is equal its diameter. Diverging section in which there is a change of stream area back to the entrance area. The recovery of KE by its conversion to pressure is nearly complete and so the overall pressure loss is small. The angle of the diverging cone may be kept as high as 140 where the pressure recovery is not of much importance. The pressure taps are made at the throat and entrance where the Venturimeter has a diameter is equal to that of the pipe. Small sized Venturimeter suitable for pipes of diameter less than 5cm is mad of brass or bronze. The inside surface is smoothly finished to reduce the friction. Large venturies are made of cast iron and the throat is smoothly finished by brass or bronze.

PROCEDURE:

Collect the apparatus required for performing the experiment. Ensure availability of water at the sump. Open the supply valve fully and wait for one minute for the flow to become

steady. Open the delivery valve fully to have maximum discharge through the pipe line. Observe the level difference between 2 limbs of the manometer and note it down. Divide the total level difference in to any convenient number of divisions (say 5 or

6) and adjust the discharge accordingly. Take the time for 10cm rise of water in the piezometer using stopwatch. Repeat the above procedure for various flow rates by closing the delivery valve

gradually. Tabulate the readings and do the calculations

SPECIFICATIONS OF VENTURIMETER:

Pipe diameter D1 = 2.5 cm Throat dia of venture = 1.48 cm Area of collecting tank = 40 x 30 cm2

OBSERVATIONS:

Sl. No:

Manometric Reading Manometric Head

(h1-h2) x 12.6 x10-2 H

Time taken for 10cm

rise of water

Actual discharge

Qact

Theoretical discharge Qth

Cd

h1 h2

cm cm m sec m3/s m3/s

1

2

3

4

CALCULATIONS AND FORMULAE:

1. Actual discharge = A×ht

in m3/s, where h =10 cm

2. Theoretical discharge = a1a2√2 gH√a12−a2

2 in m3/s

Where A= Area of the collecting tank

a1 = Area of the inlet pipe

a2 = Area of the throat h = 10 cm

g = Acceleration due to gravity, 9.81 m/s2

t = Time for collecting 10cm of water

Specific gravity of mercury = 13.6 Specific gravity of liquid water = 1

Coefficient of discharge =Qactual

Qtheoretical

GRAPHS : Cd Vs Head

Qact Vs Head

Calibration Graph

Log Qact Vs Log H

RESULTS:

The given Venturimeter was calibrated and coefficient of discharge was determined. Graphs were also plotted.

INFERENCES:

Exp: 2 CALIBRATION OF TRIANGULAR NOTCH

AIM: To calibrate the given triangular notch and determine the coefficient of

discharge

APPARATUS:Triangular notch experimental setup, Stopwatch.

PRINCIPLE:

Notch is a small structure with sharp edge used to measure rate of flow in canals,

streams and channels. The flow of water in the canals is obstructed by notch structure. This

will cause rise of water on upstream side of notch and head builds above sill level of the

notch. This causes the flow over the notch. By principle, kinematic head is converted in to

static head and again is converted to kinetic head. The discharge of flow through triangular

notch is directly proportional to H2.5, where H is head over the sill of the notch. Notch is

usually made in a smooth plane, vertical plate and its edges are levelled on the downstream

side.

PROCEDURE:

Collect the apparatus required and ensure availability of water in the sump.

Open the supply valve so as to adjust the level of water to sill level.

Observe and note down the initial sill level reading.

Vary the discharge for various openings of the notch (say 5 or 6) and take

hook gauge reading each time.

Each time, note down the time for 10cm rise of water in the piezometer

using stopwatch.

Tabulate the readings and do the calculations.

Specification of the notch setup:

Angle of notch = 600

Area of collecting tank = 40 x 30 cm2

OBSERVATIONS:

Initial Sill level reading (h1) = ….... cm

Sl.No:

Hook gauge readingHead over

the notch H

= h1-h2

Time taken

for 10cm

rise of

watert

Actual

DischargeQact

Theoretical

dischargeQth

Cd

Final hook gauge reading

(h2)

cm m sec m3/s m3/s

1

2

3

4

Calculations and Formulae:

1. Actual discharge = Qact = A×ht

in m3/s

2. Theoretical discharge=815tan

θ2

√2 g H52, in m3/s

Where = Angle of the notchϴ

H = Head over the notch

G = =Acceleration due to gravity

3. Coefficient of discharge = Qact

Qth

Graphs:

Cd Vs Head Qact Vs Head Log Qact Vs Log H

Results:

The given triangular notch was calibrated and coefficient of discharge was determined. Graphs were also plotted.

Inferences:

Exp no: 3 CONSTANT SPEED CHARACTERISTICS OF CENTRIFUGAL PUMP

Aim:To perform a test at constant speed and plot the characteristic curves of a centrifugal

pump

Apparatus : Centrifugal pump test rig, Stopwatch, measuring scale.

Principle:

Centrifugal pump consists of an impeller on which a series of curved vanes are fixed.

It is mounted on the shaft, which is driven by an electric motor. A gradually enlarging cross

section from the impeller outlet of delivery pipe called casing is provided for housing the

impeller and supporting bearing provided for the shaft carrying the impeller. The purpose

of casing is to guide the liquid from the impeller and convert the KE into useful pressure

energy and lead the water to the delivery pipe.

It works on the principle of centrifugal action. Before starting the pump, Priming is

done. This is done for the removal of air trapped in the pipelines.The suction pipe, casing

and portion of the delivery pipe up to the delivery valve are completely filled with liquid to

be pumped. Rapid motion imparted to the impeller then builds up centrifugal force which

throws the liquid towards the impeller periphery. This causes pressure gradient in the

suction pipe. ie: a partial vacuum exists in the impeller eye while the liquid in the sump is at

atmospheric pressure. Consequently the liquid from the sump is sucked in towards the

impeller eye. When the liquid passes through the impeller, it receives the energy and that

results in the growth of both pressure and velocity. The casing collects the liquid from the

impeller and guides it to the delivery pipe. Since the casing increases in cross sectional

area, towards the delivery, kinetic head is partially converted in to pressure head before

the liquid leaves the pump.

Procedure:

Ensure the availability of water in the sump

Prime the pump to remove any air bubbled trapped inside

Switch on the pump keeping the delivery valve fully closed.

Open the delivery valve fully.

Note down the suction and delivery pressures from the pressure gauges.

Note down time for 10cm rise of water in the piezometer using stopwatch

Note down the time for 10 pulses of energy meter

Repeat the above procedure for various flow rates till full closure of the delivery

valve

Tabulate the readings and do the calculations

Specifications of the Pump:

Area of the collecting tank = 70 x 40 cm2

Datum head z = 0.48 m

Energy meter constant = 3200

Speed of Motor = 250 rpm

Motor efficiency = 45 %

Sl.

No:

Ps

(Suction Pressure)hsw =

(bx10)hd

hdw = (hd

x 10)

Total headTime for

10 cm

rise of

water

(T)

Qact

Time for 10

impulses of

energy meter

(t)

Output

power

Input

powerEfficiency

hsw+hdw+za b

mmof Hg kg/cm2 m of water kg/cm2m of

waterm sec m3/s sec Watts Watts %

OBSERVATIONS:

Calculations and formulae:

1. Actual discharge = Qact = A×hT

in m3/s

2. Total head = hsw+hdw+z in meters

3. Input power ¿η×3600×N e×1000

t × kin Watts

4. Output power = ρgQH in Watts

5. Efficiency =OutputInput

in %

6. Specific speed = Ns=N ×√Q

H34

in rpm

Where A = Area of collecting tank in m2

h = 10cm

T = Time taken for 10 cm rise of water K = Energy meter constant

= Density of waterρ t = Time for 10 impulses of energy meter

Ne = No. of impulses of energy meter

= motor efficiency = 0.45ɳ H = total head N = Speed of the motor in rpm

Graphs:

Input Vs discharge

Efficiency Vs Discharge

Total head Vs Discharge

Results:

The test on centrifugal pump was conducted at constant speed and performance curves

were plotted

Inferences:

Exp No: 4 DETERMINATION OF HYDRAULIC COEFFICIENTS OF AN ORIFICE

AIM:

To determine coefficient of contraction, coefficient of velocity and coefficient of discharge of a given small circular orifice

APPARATUS:

Hydraulic coefficients experimental setup.

PRINCIPLE& FORMULAE:

Discharge through an orifice is a function ofhead causing the flow. The static head in the balancing tank is converted intokinetic head due to the flow through the orifice. In viscous fluid flow, due to viscous effects there is always some loss of energy and accordingly the actual velocity is always less than the theoretical velocity hence Cv is less than 1 [0.95-0.99]. due to convergence of streamlines in to a section of minimum cross sectional area[Vena contracta- one half of the orifice diameter from downstream edge of the orifice] area of jet at vena contracta is much less than area of the orifice. Cc varies from 0.61-0.69. Cd has an average value of 0.6

1. Theoretical velocity of flow of jet V = √2× g×H

2. Actual discharge = A× xt

in m3/s3. Qth = Area of orifice x Theoretical velocity of the jet = ao x √2× g×H

Coefficient of discharge Cd = Qact

Qthin m3/s

Where Cc = Coefficient of contraction,

Cv = Coefficient of velocity = Actual velocity at Vena contracta/ Theoretical

Velocity

Also Cv = √ X2

4YH

Cc = Area of jet at Vena contracta/ Area of orifice = ac/a = Cd/Cv

PROCEDURE:

Fit the required orifice plate in the housing Allow the water to flow through the orifice such that the head of water in the orifice

tank remains constant by regulating inlet valve Measure the hook gauge reading using vertical and horizontal scale at the vena

contracta. Position the hook gauge at any point in the trajectory and take readings Note the time required for the water level to rise by x cm in the collecting tank. Adjust the inflow in to the orifice tank and let the height of the water in the tank

again to be kept steady at a different value and repeat the experiment as before. Obtain readings at least for 6 different heads above the centre of the orifice.

OBSERVATIONS:

Sl.No Head

Time for 10cm rise of water

Actual Discharge

Theoretical discharge

Hook gauge reading

X = X1-X0 Y=Y1-Y0 Cd Cc Cv

H t Qa Qth X1 Y1

cm cm cm3/s cm3/s cm cm cm cm

1

2

3

4

GRAPHS: Cd Vs H, Cv Vs H, Cc Vs H

RESULTS:

The flow through the orifice experiment is performed and hydraulic coefficients are also calculated.

INFERENCES:

Exp no: 5 CONSTANT SPEED CHARACTERISTICS OF A RECIPROCATING PUMP

AIM:

To perform a test at constant speed and plot characteristic curves of a reciprocating pump

APPARATUS:Reciprocating pump test rig, stopwatch, meter scale.

PRINCIPLE:

It is a positive displacement pump because it sucks and rises the liquid in upward direction by actually displacement of the piston or plunger with the cylinder. The amount of liquid pumped is equal to the volume displaced by the piston. A reciprocating pump consists of a piston, which has a reciprocating motion in a closely fitted cylinder. The piston moves backward, partial vacuum is created in the cylinder and liquid rises from the sump and fills the cylinder through suction pipe due to pressure difference between cylinder and sump and delivery valve is closed. When piston moves forward in the cylinder, pressure of water closes the suction valve and opens the delivery valve. Thus water is forced up the delivery pipe. The liquid is carried through the delivery pipe to the discharge tank. The reciprocating pump is fitted with air vessel to ensure continuity of flow [Uniform flow].

PROCEDURE:

Ensure availability of water in the sump. Switch on the pump with delivery valve fully open. Note down the suction and delivery pressures from the gauges. Take the time for 10cm rise of water in the piezometer using stopwatch. Note down the time taken for 10 impulses of energy meter disc. Repeat the procedure by varying the discharge. Tabulate the readings and do the calculations.

SPECIFICATIONS OF THE PUMP:

Datum head = 0.405 m Area of collecting tank = 29.5 x 29.5 cm2

Energy meter constant = 3200 Length of the stroke = 4.5 x 10-2 m Bore of the cylinder = 4 x 10-2 m Speed = 250 rpm

OBSERVATIONS:

Sl. No.

Suction Pressure

Suction Head

Delivery Pressure

Delivery Head Total

head

Time for

10cm rise of water

(t)

Qact

Time for 10 impulses of

energy meter disc (T)

Output power

Input power η %

SlipPs

Hsw = (Ps/760) x10

Pd Hdw = (Pd x 10)

mm of Hg

meters of water

kg/cm2 metersof water

m sec m3/s sec Watts Watts

CALCULATIONS AND FORMULAE:

1. Actual discharge = ( Area×x )/¿t in m3/s, Where x = 10 cm

2. Total head = Hsw+Hdw+Z in meters

3. Input power = n×3600×ηmotor×1000

T ×kWatts

4. Output power = ρ gQHWatts

5. Efficiency = (Output/Input) x 100 %

6. Qth = LAN60

7. % Slip = (Qth−Qact )

Qth

×100

Where,

n = no: of impulses of energy meter disc T = time taken for 10 impulses

k = energy meter constant ηmotor = motor efficiency = 0.45

= density of liquid = 1000 kg/mρ 3 H = Total head of water in meters.

Q = Actual discharge in m3/s Hsw = Suction head in m of water =[Ps/760] x

10

Hdw = Delivery head = Pd x 10 meters Z = Datum head

t = time taken for 10 cm rise of water Ps = Suction pressure

Pd = Delivery pressure L = Length of the stroke

A = Area of cylinder N = Speed of the pump in rpm

GRAPHS:

Input Vs Head

Q Vs Head

Efficiency Vs Head

% slip Vs Head

RESULTS:

The test was performed at constant speed and characteristic curves were plotted.

INFERENCES:

Exp. No: 6 CONSTANT HEAD CHARACTERISTICS OF PELTON WHEEL TURBINE

Aim: To perform a test at constant speed and plot the performance characteristics of a

Pelton wheel turbine.

Apparatus: Pelton wheel turbine test rig, stop watch etc.

Principle: Hydraulic turbines are water turbines which convert the hydraulic energy to

mechanical energy. This mechanical energy is converted into electrical energy by an

electrical generator, which is directly coupled with turbine shaft. A Pelton wheel is

commonly used tangential flow impulse turbine working under high head and requires

small quantity of water. A Pelton wheel consisting of a runner on which a double

hemispherical buckets are fixed at its periphery. This runner is mounted on a shaft which is

connected to a generator.

Water is transferred from reservoir to the turbine installed in the power

house through penstock. The lower end of the penstock is fitted with a nozzle to generate

high speed jet. The whole potential energy is thus converted in to kinetic energy before the

jet strikes the buckets of the runner. The jet of the water generated from the nozzle strikes

the buckets in the direction tangential to the wheel. The impact of water on the buckets

causes the runner to rotate, thus develops mechanical energy. This mechanical energy is

converted in to electrical energy by the generator. The water coming out of the wheel is

discharged in to tailrace. The pressure all over the wheel is constant and equal to the

atmosphere so that the energy transfer occurs purely due to the impulse action.

PROCEDURE:

Ensure availability of water in the sump. Calculate the maximum load that can be applied on the turbine. Ensure that the turbine is under no load condition.

Switch on the motor with delivery valve fully closed. Take the reading of the spring balance, manometric head and speed of the turbine. Apply a small load on the turbine and open the cooling water supply. Adjust the delivery valve so as to maintain the head at a rated value. Note down the readings Repeat the procedure up to the maximum load and tabulate the readings

OBSERVATIONS:

Sl.

No:

LoadVenturimeter

Reading H1

Qactual SpeedInput

Power

Output

PowerȠ

W s W-s

Inlet h1

Throat

h2

kg kg kg/cm2 kg/cm2 m3/s rpm W W %

Specifications:

Speed of the turbine =

Diameter of brake drum = D =

Diameter of Rope = d =

Effective diameter = De =

Effective radius = Re =

Output Power of the turbine =

Head on the Turbine = H =

Calculations & Formulae:

Calculation of Maximum Load:

Output Power, Po =2π NT60

=2π N (W−s )×Re×9.81

60

Maximum Load (kg) = (W-s) =60× Po

2π N ×Re×9.81

Actual discharge, Q = K √H 1

Where K = 0.0055

Input Power, Pi = ρ gQH

Efficiency = (Po/Pi) x 100

LEGENDS:

H = Head on the turbine Q = Actual discharge H1 = Venturi Head

= Density in kg/mρ 3 W = Applied load + Weight of the hanger

GRAPHS:

Efficiency Vs Head Discharge Vs Head Input Vs Head Output Vs Head

RESULTS:

The test was conducted at constant speed and constant head and performance curves were plotted.

INFERENCES:

Exp No: 7 CONSTANT SPEED CHARACTERISTICS OF GEAR OIL PUMP

Aim: To perform a test at constant speed and plot the performance curves of a gear oil pump.

APPARATUS: Gear Pump test rig, Stopwatch, Measuring scale.

PRINCIPLE: It is a rotary displacement pump primarily used as power sources in

hydraulic control systems and to supply pressurized oil for lubrication of motors, turbines

and machine tools. Such pumps have advantages of both centrifugal and reciprocating

pumps. The unit consists of 2 identical meshing spur gears with involute teeth. One of the

gears is keyed to the driving shaft of the motor and other gear revolves idly. These gear

rotate in opposite directions in a close fitting stationary housing. The oil coming in at the

suction port fills the space between the teeth, is carried around the periphery of the

revolving gear and is finally pushed out to the discharge port. The teeth of the gears have a

perfect meshing and that serves both the transmit the drive and to maintain a seal between

the suction and discharge side. Care is taken to ensure that the oil trapped between the

successive lines of contact doesn’t build up pressure. A change in the flow direction can be

affected by reversing the direction of the gear assembly. But the spur gear pup delivers

hydraulic fluid always at right angle to the axis of rotation.

PROCEDURE:

Ensure availability of oil in the sump.

Switch on the motor with delivery valve fully opened.

Note down the reading of the pressure gauges at the suction and delivery sides.

Note down the time for 10 cm rise of oil using stopwatch.

Note down time for 10 impulses of the energy meter disc using stop watch.

Repeat the procedure for various flow rates and tabulate the readings.

SPECIFICATIONS :

Area of the collecting tank : 25 x 25 cm2

Datum head, z : 0.305 cm

Motor efficiency : 45%

Energy meter constant : 3200

OBSERVATIONS:

Sl. NoSuction

Pressure Delivery Pressure

Time taken for

10 impulses of energy

meter disc

Time taken for 10

cm rise of oil

Total Head

Qactual Output Input Efficiency

Ps Ps Pd Tm t H Qa Po Pi Ƞ

mm of Hg Kg/cm2 Kg/cm2 sec sec m m3/s W W %

CALCULATIONS & FORMULAE:

Total head = {(Ps+Pd) x12.5+z} in meters

Actual discharge =A×ht

Output power = gQH wattsρ

Input power =N e×3600×ηm×1000

T m×kwatts

Efficiency = (Output/Input ) x 100%

GRAPHS:

Vs HeadȠ Qact Vs Head Input Vs Head Output Vs Head

RESULTS:

The test was performed at constant speed and performance curves were also plotted.

INFERENCES:

Exp No: 8 CALIBRATION OF RECTANGULAR NOTCH

AIM : To calibrate the given rectangular notch and plot the calibration curve

APPARATUS : Rectangular notch experimental setup, Stopwatch.

PRINCIPLE : Notch is a small structure with sharp edge used to measure rate of

flow in canals, streams and channels. The flow of water in the canals is obstructed by notch

structure. This will cause rise of water on upstream side of notch and head builds above sill

level of the notch. This causes the flow over the notch. By principle, kinematic head is

converted in to static head and again is converted to kinetic head. The discharge of flow

through rectangular notch is directly proportional to H1.5, where H is head over the sill of

the notch. Notch is usually made in a smooth plane, vertical plate and its edges are levelled

on the downstream side.

PROCEDURE:

Collect the apparatus required and ensure availability of water in the sump. Open the supply valve so as to adjust the level of water to sill level. Observe and note down the initial sill level reading. Vary the discharge for various openings of the notch (say 5 or 6) and take

hook gauge reading each time. Each time, note down the time for 10cm rise of water in the piezometer

using stopwatch. Tabulate the readings and do the calculations.

SPECIFICATION OF THE NOTCH SETUP:

Area of collecting tank = 40 x 30 cm2

Width of the notch =

OBSERVATIONS:

Sl. No:

Hook gauge readingHead over

the notch =

h1-h2

Time taken

for 10cm

rise of

water

Actual

Discharge

Theoretical

dischargeCd

Final hook gauge reading

(h2) H t Qact Qth

cm m sec m3/s m3/s

1

2

CALCULATIONS & FORMULAE :

1. Actual discharge = Qact = A×ht

in m3/s

2. Theoretical discharge Qth =23×L×√2g H

32, in m3/s

Where L = Length of the notch

H = Head over the notch

G = =Acceleration due to gravity

3. Coefficient of discharge = Qact

Qth

GRAPHS:

Cd Vs Head Qactual Vs Head Calibration graph

RESULTS:

The given rectangular notch was calibrated and graphs were plotted.

INFERENCES:

Exp No: 9 CALIBRATION OF ORIFICE METER

AIM:

To calibrate the given Orificemeter and to plot the calibration curve.

APPARATUS : Orificemeter experimental setup, stopwatch

PRINCIPLE: An Orificemeter is a flow measuring device. It consists of a thin and flat

circular plate with a central circular hole called orifice. This plate is inserted in to a pipe

normal to the direction of flow. Due to the orifice, contraction of the jet occurs at a distance

d1/2 from the plate. The jet area is least at the point called Venacontracta. The pressure

difference between inlet section and Venacontracta is created by reducing the cross-

sectional area of the flow passage.

PROCEDURE:

Collect the apparatus required for performing the experiment. Ensure availability of water at the sump. Open the supply valve fully and wait for one minute for the flow to become steady. Open the delivery valve fully to have maximum discharge through the pipe line. Observe the level difference between 2 limbs of the manometer and note it down. Divide the total level difference in to any convenient number of divisions (say 5 or

6) and adjust the discharge accordingly. Take the time for 10cm rise of water in the piezometer using stopwatch. Repeat the above procedure for various flow rates by closing the delivery valve

gradually. Tabulate the readings and do the calculations

Sl. No:

Manometric Reading

Manometric Head (h1-h2) x 12.6 x10-2

H

Time taken for 10cm

rise of water

Actual discharge

Qact

Theoretical discharge Qth

Cd

h1 h2

cm cm m sec m3/s m3/s

1

2

3

4

SPECIFICATIONS:

Pipe diameter D1 = 2.5 cm Area of the collecting tank = 40 x 30 cm2

CALCULATIONS & FORMULAE:

1. Actual discharge = A×ht

in m3/s, where h =10 cm

2. Theoretical discharge = a1a2√2 gH√a12−a2

2 in m3/s

Where A= Area of the collecting tank

a1 = Area of the inlet pipe

a2 = Area of the orifice

h = 10 cm

g = Acceleration due to gravity, 9.81 m/s2

t = Time for collecting 10cm of water

Specific gravity of mercury = 13.6 Specific gravity of liquid water = 1

Coefficient of discharge =Qactual

Qtheoretical

GRAPHS: Cd Vs Head

Qact Vs Head

Calibration curve

RESULTS:

The Orificemeter was calibrated and calibration curves were plotted.

INFERENCES:

Exp No: 10 DETERMINATION OF METACENTRIC HEIGHT