SSC JE Mechanical Engineering 2017 Set 4 Paper

Centrifugal pumps are used to transport fluids by conversion of rotational kinetic energy to hydrodynamic energy of the fluid flow. The fluid enters the pump along or near to the rotation axis so its pump used as a low specific speed.
${\mathit{N}}_{\mathit{s}}=\frac{\mathit{N}\sqrt{\mathit{Q}}}{{\mathit{H}}^3∕4}$
Ranking of specific speed
Axial flow > mixed flow > Francis vane > Radial flow