Reciprocating Pump Test Rig Final

PERFORMANCE TEST ON RECIPROCATING PUMP

Aerospace Engineering Department, IIST

Exp no: Date:

PERFORMANCE TEST ON RECIPROCATING PUMP Aim : To conduct the performance test on the given Reciprocating Pump and Plot the following characteristic curves. 1.

Input power

Vs

Head

2.

Discharge

Vs

Head

3.

Efficiency

Vs

Head

4.

Percentage Slip

Vs

Head

Specifications : Type

-

Single cylinder Double acting

Bore diameter

-

40 mm

Stroke length

-

45 mm

Motor Power

-

1 HP

Speed of motor

-

Energy meter constant -

1440 rpm 1600 impulse/kWhr

Apparatus : Reciprocating Pump test rig with collecting tank, Energy meter, Pressure gauge, etc. Theory : Reciprocating pumps are classified as positive displacement pumps as a definite volume liquid is trapped in a chamber which is alternatively filled from the inlet and emptied at a higher pressure through the discharge. Most piston pumps are acting with liquid admitted alternatively on both sides of the piston so that one part of the cylinder is being filled while the other is being emptied. This arrangement helps to minimize fluctuations in discharge. Overall efficiency of the pump is the ratio of output power to input power.

ie,

η 

Output Power  100 % Input Power

=

ρ g Qa H watts

Where, ρ

=

Density of water in kg/m3.

g

=

Acceleration due to gravity in m/s2.

Output Power,

Po

Aerospace Engineering Department, IIST

Qa

=

Actual discharge in m3/s.

H

=

Total head of water in m.

=

Hs + Hd + X

=

Suction Head in m of water.

=

Suction gauge reading in mm of Hg Density of mercury X m of water 1000 Density of water

=

Delivery Head in m of water.

=

Delivery gauge reading in kg/cm 2 X 10 4 m of water Density of water

=

Level difference between gauges in m.

Motor Input Power, Pim

=

n X 3600 X 1000 te X K

Where,

n

=

number of impulses in energy meter.

te

=

time for 'n' number of impulses.

K

=

Energy meter constant.

=

Pim X m

m

=

Efficiency of motor

Qa

=

Ah t

A

=

Area of collecting tank in m2.

h

=

rise of water in collecting tank in m.

t

=

time taken to h rise of water in s.

Theoretical discharge, Qth

=

2LA N 3 m /s 60

L

=

Length of stroke in m.

A

=

Area of piston in m2.

N

=

Speed of the crank in rpm.

Hs

Hd

X

Input Power to pump, Pi Where, Actual discharge, Where,

Where,

Percentage Slip =

watts

= 75%

m3/s

Q th  Q a X 100 % Q th

Procedure : 1)

Keep the delivery valve open and switch on the pump.

2)

Slowly close partially the delivery valve and maintain a constant head.

3)

Note the delivery and suction gauge reading.

Aerospace Engineering Department, IIST

4)

Note the time for 10 impulses of energy meter.

5)

Close the valve through which water flows out of the collecting tank and note down the time taken for 10 cm rise in water level in the collecting tank.

6)

Note the speed of the crank in rpm using the digital tachometer.

7)

Repeat the procedure for various openings of the delivery valve.

Aerospace Engineering Department, IIST

Aerospace Engineering Department, IIST

7

6

5

4

3

2

1

Sl. No:

kg/cm

mm of Hg

2

Pd

Ps

RPM

N

Suction Delivery gauge gauge Speed reading reading

s

1

s

2 s

mean

Time for 10 impulses of energy meter ( te )

s

1 s

2 s

mean

Time for 10 cm rise in collecting tank (t)

m of water

Hs m of water

Hd

Suction Delivery Head Head

m of water

H m /s

3

Qa m /s

3

Qth

Total Theoretical Actual Discharge Head Discharge

W

Po

Output Power

W

Pi

Input Power

%

 %

Overall % Efficiency Slip

Observation Table :

Sample Calculations: Set No _____

Result :

Inference :

Aerospace Engineering Department, IIST