Centrifugal Pumps Design and Application 2nd ed - Val S. Lobanoff, Robert R. Ross (Butterworth-Heinemann, 1992)

High Speed Pumps 189
Figure 11-5. Inducer characteristics curves.
Commercial inducers have tended to result in performance suction specific
speeds on the order of S s = 20,000 to 24,000. This level of performance
entails some compromise from the standpoint of consideration of
inducer cavitation but provides respectable inducer design, though perhaps
not ultimate design. These suction specific speeds generally
produce dramatic improvement in suction performance, frequently providing
up to 80% NPSHR reduction over uninduced pumps.
Freedom from long-term cavitation erosion to the inducer itself is provided
by observing experimentally established cavitation limitations in
the inducer design. The cavitation limitation is related to tip speed, fluid
specific gravity, and the inducer material as follows:
where K is an experimentally established constant which varies with the
inducer hydraulics and material of construction.
Commonly used 316 stainless steel is considered to possess "good" resistance
to cavitation erosion, but exploitation of materials with superior