In a centrifugal pump, the impeller does the work on the fluid (typically water) to increase its pressure and kinetic energy. Here's a breakdown of the process:
Impeller Action:
The rotating impeller blades impart kinetic energy and a radial outward motion to the fluid entering the center (eye) of the impeller.
As the fluid moves through the impeller channels, it gains velocity in the tangential direction (along the direction of impeller rotation).
Energy Transfer:
The increased kinetic energy from the impeller translates to a pressure rise in the fluid as it exits the impeller towards the volute (discharge casing). This pressure increase is the main purpose of the pump.
There's also a conversion of some kinetic energy to pressure head due to the volute design, which gradually increases the flow area as it wraps around the impeller.
Work Done Calculation:
The work done per unit mass of fluid by the impeller can be expressed by an equation that considers:
Increase in Kinetic Energy (KE) head
Increase in Static Pressure head
Change in KE due to the fluid being slowed down in the diffusion action of volute
learn about Centrifugal pump Workdone by Impeller and Efficiencies in this easy to understand lecture
Dr. Amit Mandal