FLUID MECHANICS LAB - NRI Institute of...

Department of Petroleum Engineering NRIH

Mr. M.VenkannaBabu (Ph.D), M.E (CAD) HOD & Asso. Professor

i

Department

Of

PETROLEUM ENGINEERING

Lab Manual for

FLUID MECHANICS

LAB (II-B.Tech II-Sem )

Prepared by

Mr. M.VenkannaBabu (Ph.D), M.E (CAD)

HOD & Asso. Professor



ii

LIST OF EXPERIMENTS

S.NO: NAME OF THE EXPERIMENT NAME OF THE EQUIPMENT PAGE

NO:

1 Calibration of Venturimeter & Orifice

meter

Venturimeter & Orifice Meter

Apparatus 1-5

2

Determination of Coefficient of

Discharge for a Small Orifice /

Mouthpiece by Constant Head Method

Small Orifice / Mouthpiece

Apparatus 6-10

3 Calibration of Contracted Rectangular

Notch and Triangular Notch

Rectangular and Triangular

Notch Apparatus 11-14

4 Determination of Friction Factor of a

Pipe

Friction Factor of a Pipe

Apparatus 15-17

5 Determination of Coefficient for Minor

Losses

Sudden Contraction In a Pipe

Line Apparatus 18-20

6 Verification Of Bernoulli’s Equation Bernoulli’s Theorem Apparatus 21-23

7 Impact Of Jets On Vanes Impact Of Jets On Flat &

Hemispherical Vanes Apparatus 24-27

8 Performance Characteristics of a Single

Stage

Single Stage Centrifugal Pump

Apparatus 28-30



1

1. CALIBRATION OF VENTURIMETER & ORIFICE METER

AIM:

To determine the Co-efficient of discharge Cd of the Venturimeter and Orifice meter.

APPARATUS:

Flow measurement device apparatus, Stop watch.

SPECIFICATIONS:

* Area of Measuring tank, “A” = 0.3m X 0.3m

* Diameter of the Venturimeter (throat), “d” = 14 mm

* Diameter of the Venturimeter (Inlet), “D” = 25 mm

* Diameter of the Orifice meter (venacontracta), “d” = 14 mm

* Diameter of the Orifice meter (Inlet), “D” = 25 mm

THEORY:

1. VENTURIMETER:

A Venturimeter is a device which is used for measuring the rate of flow of fluid through pipe

line. The basic principle on which a venturimeter works is that by reducing the cross-sectional area of

the flow passage, a pressure difference is created between the inlet and throat & the measurement of the

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

A Venturimeter consists of:

1. An inlet section followed by a convergent cone,

2. A Cylindrical throat & a gradually divergent cone.



2

The inlet section of the Venturimeter is of the same diameter as that of the pipe which is

followed by a convergent cone. The convergent cone is a short pipe which tapers from the original size

of the pipe to that of the throat of the Venturimeter. The throat of the venturimeter is a short parallel

side tube having its cross-sectional area smaller than that of the pipe. The divergent cone of the

venturimeter is 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 & the throat, of the venturimeter, pressure taps are

provided through pressure ring. Venturimeter provides a constriction in the flow area which produces

an accelerated flow. Consequently, there will be a fall in static pressure. Hence, the measurement of

drop in static pressure provides an accurate measure of the flow rate in the pipe. The application of

Bernoulli’s Equation between the inlet section and the throat section and the use of continuity equation

leads to the following expression for the flow rate. Venturi Head is directly related to the flow rate.

Thus the observed experimentally to be true and the value of Cd is seen to vary from 0.95-0.99 for Re >

105.

2. ORIFICE METER:

An ORIFICE METER is another simple device used for the measuring the discharge through

pipes, orifice meter also works on the same principle as that of Venturimeter i.e., by reducing the cross-

sectional area of flow passage, a pressure difference between the two sections before and after Orifice

is developed and the measurement of the pressure difference enables the determination of the discharge

through the pipe. However, an orifice meter is a cheaper arrangement for discharge measurement

through pipes and its installation requires a smaller length as compared with Venturimeter. As such

where the space is limited, the orifice meter may be used for the measurement of discharge through

pipes. In practice it is customery to account for this loss by insertion of an experimentally determined

co-efficient of known as “Coefficient of discharge ’’.

Thus the equation for actual discharge becomes

Qact = Cd Qth



3

The value of co-efficient of discharge -Cd depends on Reynolds number (Re) of the flow and

increases with increase in Reynolds’s number for the same throat ratio. This has been observed

experimentally to be true and the value of Cd is seen to vary from 0.95-0.99 for Re > 105.

PROCEDURE:

1. Fill-in the sump tank with clean water.

2. Keep the delivery valve closed.

3. Connect the power cable to 1 Ph, 220 V, 10 Amps with earth connection.

4. Switch-ON the Pump & open the delivery valve.

5. Open the corresponding ball valve of the Venturimeter pipe line.

6. Adjust the flow through the control valve of the pump.

7. Open the corresponding ball valves fitted to Venturi tappings.

8. Note down the differential head reading in the Manometer. (Expel if any air is there by opening

the drain cocks provided with the Manometer).

9. Operate the Butterfly Valve to note down the collecting tank reading against the Known time

and Keep it open when the readings are not taken.

10. Change the flow rate & repeat the experiment.

11. Open the corresponding ball valve of the Orifice pipe line.


13. Open the corresponding ball valves fitted to Orifice tappings.

14. Note down the differential head reading in the Manometer. (Expel if any air is there by opening



and Keep it open when the readings are not taken.

16. Change the flow rate & repeat the experiment.

PRECAUTIONS:

1. Do not start the pump if the voltage is less than 180v.

2. Do not forget to give electrical neutral & earth connections correctly.

3. There is no danger of water being not there in the sump tank, since the measuring tank is fitted

with overflow pipe.

CALCULATIONS:

1. VENTURIMETER:


* Acceleration due to gravity, “g” = 9 .81 m/sec2



4

* Diameter of the Venturimeter (throat), “d = 13 mm

* Diameter of the Venturimeter (Inlet), “D” = 25 mm

* R = Rise of water level for time‘t’ secs in cm. “R” = 10cm

* a1 = Area of Intel section of venturi = Π D2/4 in m

2 = m

2

* a2 = Area of Throat section of venture = Π d2/4 in m

2 = m

2

1. THEORETICAL DISCHARGE:

* Loss of head ‘H’ = 12.6 x (h1 –h2) in m

theoQ m3 / Sec

2. ACTUAL DISCHARGE:

* t = time taken in seconds for ‘R’ cm rise of water.

actQ m3 / Sec

3. CO-EFFICIENT OF DISCHARGE:

dC

TABLE OF CALCULATIONS:

S. NO:

TIME

TAKEN

FOR 10cm

RISE OF

WATER t

'sec

Actual

Discharge

=Qact

‘m3/sec.

Differential head in mm of Hg

h1 h2 H

Theoretical

Discharge

=Qtheo

‘m3/sec.

Co-efficient of

Discharge

Cd=Qact / Qtheo

1.

2.

3.



5

2. ORIFICE METER:

* Diameter at the vena contracta, “d = 13 mm

* Diameter of the Inlet section, “D” = 25 mm


* a1 = Area of Intel section = Π D2/4 in m

2 = m

2

* a2 = Area of vena-contracta = Π d2/4 in m

2 = m

2

1. THEORETICAL DISCHARGE:

* Loss of head ‘H’ = 12.6 x (h1 –h2) in m

theoQ m3 / Sec

2. ACTUAL DISCHARGE:

* t = time taken in seconds for ‘R’ cm rise of water.

actQ m3 / Sec

3. CO-EFFICIENT OF DISCHARGE:

dC


S. NO:

TIME

TAKEN

FOR 10cm

RISE OF

WATER t

'sec

Actual

Discharge

=Qact

‘m3/sec.

Differential head in mm of Hg

h1 h2 H

Theoretical

Discharge

=Qtheo

‘m3/sec.

Co-efficient of

Discharge

Cd=Qact / Qtheo

1.

2.

RESULT:



6

2. DETERMINATION OF COEFFICIENT OF DISCHARGE FOR A

SMALL ORIFICE & MOUTHPIECE BY CONSTANT HEAD

METHOD

AIM:

The objective of this experiment is to find and study the variations of hydraulic coefficients of

the given orifice and mouthpiece.

APPARATUS:

Orifice apparatus, sliding hook gauge to measure the co-ordinates of the moving jet, Mouthpiece

apparatus and measuring tanks with a stopwatch for measuring the actual flow rate.

THEORY:

1. SMALL ORIFICE:

Orifice is at sharp edged small circular hole fitted in one side of a reservoir containing fluid. It

may be classified on the basis of their size, shape, upstream edge and the discharge conditions. Most

commonly used are circular and rectangular orifices. It is used to determine the discharge through a

tank. The thickness of the wall is assumed to be small compared to the diameter of the orifice. Because

of the convergence of the stream-lines approaching the orifice, the cross section of the jet decreases

slightly until the pressure is equalized over the cross-section, and the velocity profile is nearly

rectangular. This point of minimum area is called the‘vena contracta’. Beyond the vena contracta,

friction with the Fluid outside the jet (air) slows it down, and the cross section increases. This

divergence is usually quite small, and the jet is nearly cylindrical with a Constant velocity. The jet is

held together by surface tension. The ratio of the area of vena contracta to the orifice area is called the

coefficient of contraction.



7

2. MOUTHPIECE:

A mouthpiece is a short pipe of length not more than two or three times its diameter, connected

to an orifice of same size provided in the wall of a reservoir containing fluid. It is an extension of the

orifice and through which the fluid is discharged.

PROCEDURE:

1. Note the dimensions of the discharge measuring tank, orifice.

2. Check that the zero of the scale of the inlet tank is the same level as the Center line of the

mouthpiece or orifice. If not, measure the difference in elevation and take it as zero error.

3. Adjust the opening of the inlet valve till the water level in the supply tank become steady.

4. Note down the head.

5. using the hook gauge arrangement measure the co-ordinates of the jet in a convenient point.

6. Using collecting tank and stop watch setup measure the actual discharge.

7. Repeat the experiment for different inlet valve openings and tabulate the readings.

8. Plot the characteristics CD Vs h, CC Vs h and CV Vs h.

9. Note the dimensions of the discharge measuring tank, mouthpiece.

10. Check that the zero of the scale of the inlet tank is the same level as the center line of the

mouthpiece. If not, measure the difference in elevation and take it as zero error.

11. Adjust the opening of the inlet valve till the water level in the supply tank become steady.

12. Note down the head.

13. Using collecting tank and stop watch setup measure the actual discharge.

14. Repeat the experiment for different inlet valve openings and tabulate the readings.



8

CALCULATIONS:

1. SMALL ORIFICE:

1. Diameter of Orifice = 0.8 cm

2. Dimension of measuring tank= 30cm x 40 cm

3. Area of measuring tank (A)=

4. Area of Orifice (ao)=

The theoretical discharge through the orifice will be,

Qth = a0 x √(2 g h)

Where,

a0 = area of the orifice (cm2)

h = Constant Head (cm)

g = acceleration due to gravity, 981 (cm/ sec2)

The actual discharge is less than the theoretical discharge due to friction loss and the loss due to

expansion of the jet. The actual discharge through the orifice can be determined using the collecting

tank and stopwatch setup.

Qact = (A x R) / t

Where,

A = area of the collecting tank (cm2).

R = height difference of the water column in the piezometer, (cm)

t = time taken to rise R meters, (sec)

The coefficient of discharge CD is defined as the ratio of the actual discharge to theoretical discharge.

The actual velocity of the jet through the orifice is found out by measuring the co-ordinates of

the moving jet and applying Newton’s laws. Refer figure below. The co-ordinates x and y of any point

on the jet are measured using the sliding hook gauge.



9

The coefficient of velocity Cv :

The coefficient of contraction CC :

RESULT:

Hydraulic coefficients,

CD =

Cv =

Cc =

2. MOUTHPIECE:

1. Diameter of mouthpiece = 2.5 cm

2. Dimension of measuring tank= 30 cm X 40 cm

3. Area of measuring tank (A)=

4. Area of Orifice (ao)=

The theoretical discharge through the mouthpiece will be,

Qth = a0 x √(2 g h)

Where,

a0 = area of the mouthpiece (cm2)

h = Constant Head (cm)

g = acceleration due to gravity, 981 (cm/ sec2)

The actual discharge is less than the theoretical discharge due to friction loss and the loss due

to expansion of the jet. The actual discharge through the orifice can be determined using the collecting

tank and stopwatch setup.

Qac = (A x R) / t



10

Where,

A = area of the collecting tank (cm2).

R = height difference of the water column in the piezometer, (cm)

t = time taken to rise R meters, (sec)

The coefficient of discharge CD is defined as the ratio of the actual discharge to theoretical discharge.

RESULT:

Hydraulic coefficients,

CD =



11

3. CALIBRATION OF CONTRACTED RECTANGULAR NOTCH AND

TRIANGULAR NOTCH

AIM:

The objectives of this experiment are

Determine the coefficient of discharge of the given external flow measuring notches for

different rates of flow,

Plot the characteristics Cd Vs. h and Qac Vs. h and Qcal Vs. h.

APPARTUS:

The given notch fitted on an open channel of the experiment setup, hook gauge to measure the

water level over the notch and measuring tank with stopwatch to measure the actual flow rate.

THEORY:

In open channel flows, weirs are commonly used to either regulate or to measure the volumetric

flow rate. They are of particular use in large scale situations such as irrigation schemes, canals and

rivers. For small scale applications, weirs are often referred to as notches and are sharp edged and

manufactured from thin plate material. The basic principle is that discharge is directly related to theater

depth above the crotch (bottom) of the notch. This distance is called head over the notch. Due to the

minimal installation costs flow rate measurement with a notch is very less expensive. The rectangular

notch is the most commonly used thin plate weir. The V-notch or Triangular notch design causes small

changes in discharge to have a large change in depth allowing more accurate head measurement than

with rectangular notch. The flow pattern over a notch or weir is complex and there is no analytical

solution to the relationship between discharge and head so that a semi-empirical approach has to be

used.

The expression for discharge over a rectangular notch is given by,

Qth =

While, for Triangular notch is,

Qth =

Where, L = width of the notch, (m)

= angle of the notch, (deg)



12

h= head of water over the notch, (m)

g= acceleration due to gravity (m/s2)

Water is allowed to pass through the given notch at different flow rates. Actual discharge

through the channel can be determined using the collecting tank and stopwatch setup.

Actual discharge, Qac = (m3/s)

Where, a = area of the collecting tank.(m2)

H = height difference of the water column in the piezometer, (m)

t = time taken to rise H meters, (sec)

RECTANGULAR NOTCH



13

TRIANGULAR NOTCH

The coefficient of discharge CD is defined as the ratio of actual discharge obtained

experimentally to the theoretical discharge. i.e.,

CD =



14

PROCEDURE:

1. Check the experimental setup for leaks. Measure the dimensions of collectingtank and the

notch.

2. Observe the initial reading of the hook gauge and make sure there is nodischarge. Note down

the still level position of the hook gauge.

3. Open the inlet valve of the supply pipe for a slightly increased discharge.Wait for some time till

the flow become steady.

4. Adjust the hook gauge to touch the new water level and note down thereading. Difference of

this hook gauge reading with initial still level readingis the head over the notch (h).

5. Collect the water in the collecting tank and observe the time t to collect Hheight of water.

6. Repeat the above procedure for different flow rates by adjusting the inletvalve opening and

tabulate the readings.

7. Complete the tabulation and find the mean value of CD.

OBSERVATIONS AND CALCULATIONS:

Length of the rectangular notch = ………m

Angle of the triangular notch =……….deg

Collecting tank area =……….m2or Use Conversion 1cm = 1.22 ltrs

S.No

Hook Gauge

Readings

Actual

Discharge

Qac

Time for H cm

rise in

collection tank

Theoretical

Discharge

Q th

Coefficient

Discharge

CD

Still

Level h1

h2

Net

h m

3/s sec m

3/s

Rectangular

Notch

1

2

3

Triangular

Notch

1

2

3

RESULTS AND INFERENCE:

The average coefficient of discharge of the given notches are,

Rectangular notch, CDR =

Triangular notch, CDT =



15

4. DETERMINATION OF FRICTION FACTOR OF A PIPE

AIM:

To determine Darcy Friction Co-efficient of flow in a pipe and to investigate the velocity for

different diameters of pipe.

APPARATUS:

Pipe friction apparatus, stopwatch.

SPECIFICATIONS:

* Pump Capacity: :0.5 HP, 1 Ph.

* Collecting (Measuring) Tank Area : 0.3m X 0.3m

* Diameters of pipes being used : 15mm, 20mm.

THEORY:

A closed circuit of any cross-section used for flow of liquid is known as a pipe. In hydraulics,

generally, pipes are assumed to be running full and of circular cross section. Liquids flowing through

pipes are encountered with frictional resistance resulting in loss of head or energy of liquids. This

resistance is of two types depending upon the velocity of flow. They are Viscous Resistance and

Frictional Resistance, due to different diameters.

The viscous resistance is due to the molecular attraction between the molecules of the fluid. At

low velocities, the fluid appeared to move in layer or lamina, and hence the nature of this flow is

termed laminar flow or Stream line. If the velocity of the liquid is steadily increased, at certain velocity

termed as the lower critical velocity the parallel bands of liquid will become wavy. On further increase

in the velocity these instabilities will increase in intensity until a velocity corresponding to the upper

critical velocity is attained. The region of flow bounded by the lower and upper critical velocities is

termed the transition zone. For all further increase in velocity of flow the streamline remains in a

diffused state and the nature of this type of flow is termed turbulent. In this case the flow is restricted

by the friction between the liquid and the pipe surface which is known as frictional resistance.



16

PROCEDURE:



3. Connect the power cable to 1 Ph, 220V, 10 Amps with earth connection.

4. Switch -ON the Pump & open the delivery valve.


6. Open the corresponding ball valves of the pipe line.

7. Note down the differential head reading in the Manometer (Expel if any air is there by opening



and keep it open when the reading are not taken.

9. Change the flow rate & repeat the experiment for different diameter of pipes

PRECAUTIONS:




with overflow pipe.

4. Initially, put clean water free from foreign materials, and change once in three months.

CALCULATIONS:

* Area of Measuring Tank, “A” = 0.3m X 0.3m

* Length of pipe, “L” = 1 m.

* Kinematic viscosity, “ν “ = 1.00 x 10-6

m2/sec

* Acceleration due to gravity, “g’’ = 9.81 m/sec2

* Diameter of pipe, “d’’ = 15mm, 20 mm, (G.I)


* a = area of pipe (Π d2/4) in m

2

= m

2

= m

2

1. Loss of Head due to Friction (hf):

* H = Difference in Mercury Column in mm of Hg in double column Manometer (h1 –h2) in mm

fh m



17

2. Discharge (Q):

* t = time taken for ‘R’ rise of water in collecting tank in sec.

Q m3 / Sec

3. Velocity Head(V):

V m / Sec

4. Friction Factor (f):

,

f

5. Reynolds Number (Re):

eR


S. NO: DIA. OF

PIPE

“D”

in‘m

TIME FOR

RISE OF

10cm

WATER “t”

in ‘sec

hf

Qa in m3 / sec

“V” in m

/sec

“f”

Re

1.

2.

3.

RESULT:



18

5. DETERMINATION OF COEFFICIENT FOR MINOR LOSSES

AIM:

To determine the coefficient of loss in sudden contraction.

APPARATUS:

Pipe fitting apparatus, stopwatch.

SPECIFICATIONS:

* Pump Capacity: :0.5 HP, 1 Ph.

* Piping system of size 25mm dia and 15mm with a flow control valve.

THEORY:

Like the straight pipes produce the friction to the flow of fluid due to its inside roughness, the

pipe fittings such as Valves, Bends, Elbows, Reducers / Expanders, etc also offer Resistance / Friction

to the flow of fluid. While the head loss due to friction in straight pipes is expressed by the standard

formulae:

The head loss due to friction in pipe fittings is expressed by

By equating (a) and (b), we get the factor K = f l/d where K is the local head loss co-efficient of

pipe fittings (non-dimensional) expressed in terms of the friction factor (f), length (l) and diameter (d)

of the pipe to which the particular type of fitting is fitted.



19

In the equations where the branches of pipes are used for flow analysis, all the resistances

offered by the fittings are expressed in “equivalent length” of pipe to which they are fitted, namely; L =

Kd/f .This is to be added to the length of the straight pipe of diameter‘d’ with the friction factor ‘f’

(0.025 generally assumed), and the analysis is done further. Note that the valve of ‘K’ is to be evaluated

from the formulae hf (pipe fitting) =KV2/ 2g where V is the velocity of fluid flowing in the pipe line of

diameter d to which the pipe fitting is fitted.

hc = V2 / (2x g ) [ 1 / Cc -1]

PROCEDURE:



3. Connect the power cable to 1 Ph, 220V, 10 Amps with earth connection.

4. Switch-ON the Pump & open the delivery valve.

5. Open the corresponding ball valve of the pipe line.


7. Open the corresponding ball valves.

8. Note down the differential head reading in the Mano-meter. (Expel if any air is there by opening

the drain cocks provided with the Manometer)

9. Operate the Butterfly Valve to note down the collecting tank reading against the known time

and keep it open when the readings are not taken.

10. Change the flow rate & repeat the experiment for different diameter of pipe fittings.

PRECAUTIONS:




with overflow pipe.


CALCULATIONS:


* Acceleration due to Gravity ‘g‘ = 9.81 m/sec2

* Diameter of Smaller pipe‘d‘ = 15 mm

* a = area of pipe (Π d2/4) in m

2

= m

2



20

1. Loss of Head due to sudden contraction (hc):

* H = Difference in Mercury Column in mm of Hg in double column Manometer (h1 –h2) in mm

1000

6.12 Hhc

m

ch m

2. Discharge (Q):


Q m3 / Sec


V m / Sec

4. Coefficient of contraction (Cc ):

1

1

2

2

c

cCg

Vh

cC


S. NO: TIME FOR RISE

OF 10cm WATER

“t” in ‘sec

Qa in m3 / sec

“V” in m /sec

“hc ’’ in

m

Cc

1.

2.

3.

RESULT:



21

6. VERIFICATION OF BERNOULLI’S EQUATION

AIM:

To Verify Bernoulli’s theorem.

APPARATUS: 1. A tapered horizontal pipe (piezometer tubes fitted at different points/sections)

2. A supply tank of water

3. A measuring tank.

4. A stop watch.

SPECIFICATIONS:


* Datum head Z = 0 (for horizontal pipe)

* Area of Ducts:

A1 A2 A3 A4 A5 A6 A7 A8 A9

39x42

mm2

36 x42

mm2

31 x42

mm2

33 x42

mm2

35 x42

mm2

36 x42

mm2

38 x42

mm2

40 x42

mm2

41 x42

mm2

THEORY:

Bernoulli’s theorem states that in a steady flow of an ideal fluid the total energy per unit mass of

fluid (at any section) remains constant along a stream line flow.

Neglecting losses, the total energy at sections 1 & 2 will have the following relation:

2

2

221

2

11

22Z

g

V

w

PZ

g

V

w

P

Where,

p/w = Pressure head,

v2

/2g = Velocity head,

z = datum head.



22

PROCEDURE:

1. By slowly opening the inlet valve allow the water to flow from the supply tank.

2. Adjust the flow in such a manner that a constant head of water is available in the supply tank (i.e,

inflow = out flow).

3. Note down the quantity of water collected (Q) in the measuring tank for a given interval of time

using a stop watch.

4. Compute the area of cross sections under the piezometer tubes.

5. Use the continuity equation to get velocities.

6. Read the pressure head (p/w) directly from the piezometer tubes at the concerned sections.

7. For horizontal pipeline ‘z’ will be constant.

8. Tabulate the various values as shown in table.

PRECAUTIONS:

1. All readings/measurements should be taken carefully.

2. Don’t start the pump if the voltage is less than 180V.

CALCULATIONS:



1. Discharge (Q):


Q m3 / Sec


V m / Sec

3. Total Head:

2

2

221

2

11

22Z

g

V

w

PZ

g

V

w

P



23


S.NO: Area of Ducts Pressure

head(P/w)

Time taken for

10cm rise of

water

Discharge,

Q

m3/s

Velocity,

Q/a

Total head,

p/w + v2

/2g + z

1. A1

2. A2

3. A3

4. A4

5. A5

6. A6

7. A7

8. A8

9. A9

RESULT:



24

7. IMPACT OF JET ON VANES

AIM:

To determine the Co-efficient of impact Jet - Vane combination by comparing the actual force

with the theoretical force for stationary Flat and Hemispherical vanes.

APPARATUS:

Nozzle housing, Nozzle, vane, Transparent, Tank, Measuring Tank, and Sump.

SPECIFICATIONS:

* Vane shapes : Flat & Hemispherical

* Jet Dia. ‘d’ : 10 mm.

* Max. Jet Force : 1.5 Kgf

* Collecting (Measuring) Tank Area : 0.3m X 0.3m

* Jet Chamber: Fixed with toughened glass windows with leak proof rubber gasket.

THEORY:

1. Flat Vane:

When the jet of water is directed to hit the vane of any particular shape, the force is exerted on it

by the fluid in the opposite direction. 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 present case, we are concerned about the force exerted on the stationary

vanes. The following are the theoretical formulae for different shapes of vane, based on flow rate.

Impulse- momentum equation: The impulse of a force F acting on a fluid mass m in a interval of time

dt is equal to the change of momentum d (mv) in the direction of force.

F. dt = d (mv)

Vd

NozzleP ipe

P la te

V

V



25

2. Hemispherical Vane:

When the jet of water is directed to hit the vane of any particular shape, the force is exerted on it

by the fluid in the opposite direction. 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 present case, we are concerned about the force exerted on the stationary

vanes. The following are the theoretical formulae for different shapes of vane, based on flow rate.

Impulse- momentum equation: The impulse of a force F acting on a fluid mass m in a interval of time

dt is equal to the change of momentum d (mv) in the direction of force.

F. dt = d (mv)

PROCEDURE:

1. Fixed 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 jet, shape of vane, flow rate, force and tabulate the results.

7. Switch OFF the pump after the experiment is over and closes the delivery valve.

8. Repeat the experiment at different flow rates with same jet and vane.

9. Change the vane and carryout the experiment with different flow rates.

CALCULATIONS:

1. Flat Vane:

* Cc = Coefficient of contraction = 0.67

* a = area of jet (Π d2/4) in m

2

= m

2

1. Discharge (Q):


V

V

V

VCo sθ

VS inθ

2θ

CURVED P LATE



26

= m3 / Sec

2. Velocity (V):

aC

QV

c = m / Sec

3. Theoretical force (Ft):

For Flat Vane: Ft = ρ a V2 = N

4. Actual Force (Fact ):

Fact = (Observed Reading in kgs + 0.25 kgs) X 9.81 Newton = N

5. Co-efficient of Impact:

CI = Fact / Ft =


S. NO: Ft

In N

Time for rise of

10cm water “t”

“Q” in

m3 / sec

“V” in

m /sec

Fact

In N

V ane coefficient

CI = Fact / Ft

1.

2.

3.

2. Hemispherical Vane:

* Cc = Coefficient of contraction = 0.67

* a = area of jet (Π d2/4) in m

2

= m

2

1. Discharge (Q):


= m3 / Sec

2. Velocity (V):

aC

QV

c = m / Sec

3. Theoretical force (Ft):

For Flat Vane: Ft = 2ρ a V2 = N

4. Actual Force (Fact ):

Fact = (Observed Reading in kgs + 0.25 kgs) X 9.81 Newton = N



27

5. Co-efficient of Impact:

CI = Fact / Ft =


S. NO: Ft

In N

Time for rise of

10cm water “t”

“Q” in

m3 / sec

“V” in

m /sec

Fact

In N

V ane coefficient

CI = Fact / Ft

1.

2.

3.

PRECAUTIONS:



3. All readings must be taken and recorded carefully.


RESULT:



28

8 . PERFORMANCE CHARACTERISTICS OF A SINGLE STAGE

CENTRIFUGAL PUMP

AIM:

To conduct performance test on the given centrifugal pump

APPARATUS:

Centrifugal pump test rig, stop watch

SPECIFICATIONS:

* Electrical Services: 230V, 15A, 1ph, 50Hz, AC with Neutral & Earth connection.

* Pump: Centrifugal pump (Kirloskar make), 1HP: Maximum Speed-3000 rpm.

* Pressure Gauges: 0-2 Kg /cm2 range connected before delivery valve.

* Vacuum Gauge: 0-760mm of Hg, connected after suction valve

* Energy Meter: Single Phase, Energy meter constant: 750 Rev/KW-Hr.

* Speed Indicator: 0-9999 RPM (Digital Type).

* Control Valves: Suction and Delivery.

* Total Head: 8 – 12 m.

THEORY:

In general a pump may be defined as a mechanical device which, when interposed in a pipe line,

converts the mechanical energy supplied to it from some external source into hydraulic energy, thus

resulting in the flow of liquid from lower potential to higher potential. The pumps are of major concern

to most engineers and technicians. The types of pump vary in principle and design. The selection of the

pump for any particular applications is to be done by understanding their characteristics. The most

commonly used pumps for domestic, agriculture and industries are; Centrifugal, Piston, Axial flow

(stage pumps), Air jet, Diaphragm and Turbine pumps. Most of these pumps fall into the main class,

namely; Rotodynamic, Reciprocating (positive displacement), Fluid (air) operated pumps. While the

principle of operation of other pumps is discussed elsewhere, the centrifugal pump which is of present

concern falls into the category of Rotodynamic pumps. In this pump, the liquid is made to rotate in a

closed\ chamber (volute casing) thus creating a centrifugal action which gradually builts up the pressure

gradient towards outlet, thus resulting in the continuous flow. These pumps compared to reciprocating

pumps are simple in construction, more suitable for handling viscous, turbid (muddy) liquids, can be

directly coupled to high speed electric motors (without any speed reduction ) & easy to maintain. But,

their hydraulic heads at low flow rates is limited, and hence not suitable for very high heads compared



29

to reciprocating pump of same capacity. But, still in most cases, this is the only type of pump which is

being widely used for agricultural applications because of its practical suitability.

PROCEDURE:

1. Fill the sump tank with clean water.

2. Keep the delivery and suction valves open.

3. Switch-ON the Mains so that the Mains-ON indicator glows. Now switch-ON the motor.

4. Note down the pressure Gauge, Vacuum Gauge and time for number of revolutions of Energy

meter disc.

5. Operate the butterfly valve to note down the collecting tank reading against the known time, and

keep it open when the readings are not taken.

6. Repeat the experiment for different openings of the delivery valve (Pressure and Flow rate),

note down the readings as indicated in the tabular column.

7. After the experiment is over, keep the delivery valve open and switch- OFF the mains.

8. Calculate the results using formulae given and tabulate it.

9. Draw the graphs of Head Vs Discharge.

PRECAUTIONS:

1. Don’t start the pump if the voltage is less than 180V.

2. Don’t forget to give neutral and earth connections to the unit.

3. Frequently (at least once in three months) grease/oil the rotating parts.

4. Replace the water possibly once in a month.

5. Don’t exceed 1.5 kg/cm2 on pressure gauge reading and never fully close the delivery valve.



30

CALCULATIONS:

1. BASIC DATA / CONSTANTS

1 kg/cm2 = 760mm of Hg (10m of water)

Energy meter constant = 1200 rev/kw-hr

Area of Collecting Tank = 0.35 X 0.35

2. Electrical Power as indicated by Energy Meter:

* T = is the time taken by the Energy meter for X revolutions, in seconds

Input Power = TC

X

7.03600 KW = KW

3. Discharge Rate “Q” in m3/sec:


= m3 / Sec

4. Total Head ‘H’ in m:

* Pressure head = 10 X P = m

* Vacuume head = Pv X 13.6/1000 = m

* Datum head = distance between pressure and vacuum gauges in m = 0 m

H = Pressure head + Vacuum head + Datum head = m

5. Hydraulic Power (Delivered by the Pump):

Out Put Power = 1000

wQH KW = m

6. Pump Efficiency.

η = PI

PO

/

/ =


S.

No

Delivery

Pressure

"P" in

Kg/cm2

Suction

Pressure

"Pv" in

mm

of Hg

Time for

"X"revs

of

energyme

ter,"T"

Time

Taken

for rise

of water

"t"Sec

Total

head

‘H’

In m

‘Q’

In

m3/sec

I / P

in

KW

O / P

in

KW

Efficienc

y ‘ η ’

1.

2.

3.

RESULT:

Date post:	27-Mar-2018
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