Net Positive Suction Head Equation - Fluid Flow
Net Positive Suction Head
It is possible to ensure that cavitation is avoided during pump operation by monitoring the net positive suction head of the pump. Net positive suction head (NPSH) for a pump is thedifference between the suction pressure and the saturation pressure of the fluid being pumped.NPSH is used to measure how close a fluid is to saturated conditions. Equation 3-19 can be usedto calculate the net positive suction head available for a pump. The units of NPSH are feet of water.
NPSH = Psuction - Psaturation
NPSH = Net Positive Suction Head (m, in)
Psuction = suction pressure of the pump
Psaturation = saturation pressure for the fluid
By maintaining the available NPSH at a level greater than the NPSH required by the pump manufacturer, cavitation can be avoided.