03-01-2013, 10:42 AM
PERFORMANCE TEST ON CENTRIFUGAL PUMP
AIM:
To determine the characteristics of Centrifugal Pump and to find out:-
Total head
Pump efficiency
Overall efficiency
To plot the following performance characteristics:-
Head Vs Discharge
Pump efficiency Vs Discharge
Pump HP Vs Discharge
THEORY:
The hydraulic machines, which convert the mechanical energy into hydraulic energy, are called pumps. The hydraulic energy is in the form of pressure energy. If the mechanical energy is converted into pressure 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.
The centrifugal pump acts as a reversed of an inward radial flow reaction turbine. This means that the flow in centrifugal pumps is in the radial outward directions.
The centrifugal pump works on the principle of forced vortex flow, which means that when an external torque rotates a certain mass of liquid, the rise in pressure head of the rotating liquid takes place. The rise in pressure head at any point of the rotating liquid is proportional to the square of tangential velocity of (i.e. rise in pressure head – V2/2g or ω2r2/2g) the liquid at that point. Thus at the outlet of the impeller where radius is more, the rise in pressure head will be more and the liquid will be discharged at the outlet with a high-pressure head. Due to this high pressure head, the liquid can be lifted to a high level.Centrifugal pump is a mechanical device, which consists of a body, impeller and a rotating mean i.e. motor, engine etc. impeller rotates in a stationary body and sucks the fluid through its axes and delivers through its periphery. Impeller has an inlet angle, outlet angle and peripheral speed, which affect the head and discharge. Impeller is rotated by motor or i.c. engine or any other device.
EXPERIMENTAL PROCEDURE:
Starting Procedure:
Clean the apparatus and make All Tanks free from Dust.
Close the drain valves provided.
Fill Sump tank ¾ with 0Clean water and ensure that no foreign particles are there.
Open Flow control Valve given on the water discharge line and Control valve given on suction line.
Ensure that all On/Off switches given on the Panel are at OFF position.
Now switch on the Main Power Supply (220 V AC, 50 Hz) and switch on the pump.
Set the desired speed of motor / pump with the help of step cone pulley arrangement.
Operate the Flow Control Valve to regulate the flow of water discharged by the pump.
Operate the Control Valve to regulate the flow of water discharged by the pump.
Record discharge pressure by means of Pressure Guage, provided on discharge line.
Record suction pressure by means of Vacuum Gauge, provided on discharge line.
Record the power consumption by means of energy meter, provided in panel.
Measure the flow of water, discharged by the pump, using Stop Watch and Measuring Tank.
Repeat the same procedure for rest of the two speeds of motor / pump.
Closing Procedure:
When experiment is over, switch off the pump first.
Switch off Power supply to Panel.
DESCRIPTION:
Centrifugal Pump Test Rig consists of a sump, a centrifugal pump, an AC motor and measuring tank. To measure the head, pressure and vacuum gauges are provided. To measure the discharge, a measuring tank is provided. Flow diversion system is provided to divert flow from sump tank top measuring tank and from measuring tank to sump tank. A valve is provided in pipeline to change the rate of flow.