It is a machine which converts mechanical energy into hydraulic energy to move liquid from one place to another place.
Centrifugal pump :
A machine which converts mechanical energy into hydraulic energy by the action of centrifugal force is known as centrifugal pump.
It is exactly the reverse of francis reaction turbine. In a reaction turbine, the water at high pressure is allowed to enter the casing. This high pressure of water gives mechanical energy at its shaft. Whereas in pump, the mechanical energy is provided to shaft. Water enters the impeller which is attached to the rotating shaft. This increases the pressure energy of the outgoing fluid. the water enters the impeller radially and leaves the vanes axially.
The centrifugal pump is so called because the pressure increases within its rotor due to centrifugal action. It consists of an impeller rotating within a case. Fluid enters the impeller in the center portion, called the eye. Then it flows outwardly through the vanes of the impeller. Then it moves centrifugally outward. The fluid receives energy from the vanes, resulting in an increase in both pressure and absolute velocity.