Effect of the Profile of Entrance of the Centrifugal Pump Impeller on Cavitation

Abstract

The effect of the impeller entrance profile upon the velocity distribution just before the vane entrance edge was investigated, and experiments were conducted to examine the effect on the cavitation of centrifugal pumps. The results were as follows. (1) The velocity distribution just before the vane entrance edge, differed according to the difference of the impeller entrance profile. The flow was considerably one-sided in case of profile A whose cross-sectional area varied suddenly. However, the velocity distribution was uniform in case of profile C whose cross-sectional area varied little. (2) Irrespective of the velocity distribution, the static pressure distribution at the point just before the vanes was almost the same for all profiles. (3) In comparison of the cavitation occurrence of profiles A and C, no distinctive difference was observed except that the head drop due to cavitation in the large flow-rate range was smaller in case of profile C.