Centrifugal pump efficiency - Mechanical, Hydraulic, Volumetric, Overall efficiencies

Performance of a centrifugal pump can be determined by finding the following efficiencies:

• Mechanical efficiency
• Hydraulic efficiency
• Volumetric efficiency
• Overall efficiency

Mechanical efficiency of a centrifugal pump (ηm):

Mechanical efficiency of a centrifugal pump (ηm) is the ratio of theoretical power that must be supplied to operate the pump to the actual power delivered to the pump.

Mechanical efficiency can be used to determine the power loss in bearings and other moving parts of a centrifugal pump. It determines the actual power that must be supplied to a centrifugal pump for desired result.

Hydraulic efficiency of a centrifugal pump (ηH):

Hydraulic efficiency of a centrifugal pump (ηH) is defined as the ratio of the useful hydrodynamic energy in fluid to Mechanical energy supplied to rotor.

Volumetric efficiency of a centrifugal pump (ηv):

Volumetric efficiency of a centrifugal pump (ηv) is defined as the ratio of the actual flow rate delivered by the pump to the theoretical discharge flow rate (flow rate without any leakage) that must be produced by the pump.
Volumetric efficiency can be used to determine the amount of loss of liquid due to leakage in a pump during the flow.

Overall efficiency of a centrifugal pump (ηo):

Overall efficiency of a centrifugal pump is the ratio of the actual power output of a pump to the actual power input to the pump. It is the efficiency that determines the overall energy loss in a centrifugal pump.

Overall efficiency of a centrifugal pump is the product of the volumetric efficiency and mechanical efficiency of a centrifugal pump.
Overall efficiency of a centrifugal pump (ηo) = Mechanical efficiency (ηm) × Volumetric efficiency (ηv)