Effects of Blade Number on Hydraulic Force Perturbation on Impeller of Volute-Type Centrifugal Pump

Abstract

Perturbations of the hydrodynamic force on a three-blade centrifugal pump impeller were analyzed by transforming the static pressure change obtained on an impeller blade into Fourier series. Comparisons of the forces exerted on a blade and an impeller were made between the three- and seven-blade impellers, and the effects of the blade number on the hydrodynamic force were examined. It is found that there are few differences in the hydrodynamic force exerted on one blade between the impellers of different blade numbers. However, the hydrodynamic force on the impeller obtained by the vector summation of each blade force exhibits larger fluctuations for the three-blade impeller than that for the seven-blade one.