The suction specific speed is mainly used to see if there will be problems with cavitation during the pumps operation on the suction side. It is defined by centrifugal and axial pumps inherent physical characteristics and operating point. The suction specific speed of a pump will define the range of operation in which a pump will experience stable operation. The higher the suction specific speed, then the smaller the range of stable operation, up to the point of cavitation at 8500 (unitless). The envelope of stable operation is defined in terms of the best efficiency point of the pump.
The suction specific speed is defined as:
where:
:suction specific speed
:rotational speed of pump in rpm
:flow of pump in US gallons per minute
: Net positive suction head (NPSH) required in feet at pump's best efficiency point