Centrifugal Pump 2
3
AIM OF THE EXPERIMENT : Determination of overall efficiency, specific speed and characteristics curves of a centrifugal pump. REQUIREMENTS : 1. Centrifugal pump test Rig 2. Tachometer 3. Stop watch 4. Steel tape THEORY :A Centrifugal pump has following three types of efficiencies 1.Overall efficieny 2. Mechanical efficiency 3.Manometric efficiency Overall efficiency is the ratio of actual work done by the pump to the energy supplied to the pump by the motor or I c engines . Mechanical efficiency is the ratio of energy available at the impeller to the energy given to theimpeller by the prime power . Manometric efficiency is the ratio of manometric head to energy supplied by the impeller in KN of water . Mathematically n max =gHm/V w1 V 1 Pump output= ωQH 75 hp Where ω= specific weight of water Q=actual discharge per second=A.h m/sec =A.hm 3 /sec H=Total head acting on the pump
Transcript of Centrifugal Pump 2
AIM OF THE EXPERIMENT : Determination of overall efficiency, specific speed and characteristics curves of a centrifugal pump.
REQUIREMENTS :
1. Centrifugal pump test Rig2. Tachometer3. Stop watch4. Steel tape
THEORY :A Centrifugal pump has following three types of efficiencies
1.Overall efficieny
2. Mechanical efficiency
3.Manometric efficiency
Overall efficiency is the ratio of actual work done by the pump to the energy supplied to the pump by the motor or I c engines . Mechanical efficiency is the ratio of energy available at the impeller to the energy given to theimpeller by the prime power . Manometric efficiency is the ratio of manometric head to energy supplied by the impeller in KN of water .
Mathematically nmax=gHm/Vw1V1
Pump output= ωQH75 hp
Where ω= specific weight of water
Q=actual discharge per second=A.h m/sec
=A.hm3/sec
H=Total head acting on the pump
¿Hs+Hp+Z+Vd2
❑−V s2
2 gm
A=Area of measuring tank in m2
h=Height of rise of water in m
I.
THE TEST RIG :The test rig consists of a centrifugal pump coupled with a moter. The power is given to moter from a main switch,which is hinged to the test rig.The delivery pipe faces the collecting tank.
A water level indicator is attached to it to show the rise of wayer. A big tank (reservoir) is kept below the collecting tank in which the foot valve and strainer of suction pipe are impressed. Apressure gauge and a vacuum gauge are fitted in the delivery pipe and suction pipe respectively. A hopper arrengement is provided in the collecting tank.
PROCEDURE: Check the priming cup,pressure gauge,vacuum gauge and mercury manometer. Close the delivery control valve .Prime the pump.Start the moter and run the pump.Note the reading of the p ressure and vacumm gauges. Note the time taken for discharge.Note the rise of water level in collecting tank.Repeat the experiment,varying head from maximum at shut_off to the minimum where gate valve is fully opened.Repeat the experiment for four different r.p.m. Stop the moter. Make necessary calculations and plot the characteristic curves.
OBSERVATION:
Sr no Particulars Run no 1
Run no 2
Run no 3
Run no 4
Run no 5
1 Delivery headin kg/cm2
2 Delivery head in m of water(Hp)3 Suction head in mm of Hg4 Suction head in m of water(H2)
5 Potential head in m (z)6 Water level in collecting tank in m (h)7 Time in second
8 Area Of Collecting Tank In m2
9 Discharge in “t”seconds (qt
10 Discharge per second Q =11 Area of suction pipe in m2
121314151617181920 Speed in rpm (N)21
