Suction, discharge , net pressure heads, specific speed and power calculations

For geometrically similar pumps, the quantity NQ^1/2 / (gh)^3/4 is a constant. It is called as the specific speed (N_s)of the pump.

Specific speed may be defined as the speed of the pump which will produce unit flow Q against unit head h under conditions of maximum efficiency. Specific speed is a dimensionless quantity.