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 the difference
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 used to
calculate the net positive suction head available for a pump.
The units of NPSH are feet of water.
where:
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.
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