Question

Mechanical efficiency of a centrifugal pump is the ratio of
A: Energy available at the impeller to the energy supplied to the pump by the prime mover.
B: Actual work done by the pump to the energy supplied to the pump by the prime mover.
C: Energy supplied to the pump to the energy available at the impeller.
D: Manometric head to the energy supplied by the impeller per kN of water.

Answer 1

A centrifugal pump converts mechanical energy into hydraulic energy and its AC motor converts the initial electrical energy to mechanical energy. Hence, to find the definition for the mechanical efficiency of a centrifugal pump, note the parameters that determine the sufficient conditions.

Complete step by step answer:
A centrifugal pump is a device that works mechanically to move a fluid by transferring the rotational energy from driven rotors that are named as impellers. They can be a single one or more than one. The impeller rotates rapidly and the fluid enters into it along the axis. It is cast out by centrifugal force through the vane tips of the impeller along the circumference.
The mechanical efficiency of a centrifugal pump can be defined as the ratio of the available energy at the impeller to the supplied energy at the prime mover.

Hence, option A is the correct answer among the given options in the question.

Note: The mechanical efficiency of the pump can also be defined as the ratio of the difference between the power input and the mechanical power loss, with the power input itself. Hence when such an option is given in the same question, it is also the answer.