Taking different centrifugal pumps (XN150-20. BX50-31, IQ100-22A, and IQ65-160) as study objects, this thesis conducted some cavitation experiments for testing pumps under the conditions of various specific speeds, variable frequencies and variable rotations. Revising the results of NPSH equated relation by making use of regression analysis with SPSS12. 0 software, it obtains an empirical formula of NPSH conversion for...