Effect of nonuniform inlet flow distribution on suction performance of centrifugal pumps (1st report, experimental results)

The flow in various types of suction casings of multi-stage centrifugal pumps is investigated experimentally, and is compared with the suction performance. The results show that the symmetrical bend type casing has poor suction performance because of distorted inflows at the impeller inlet section, while better suction performance is obtained from the volute type casing which has fairly good flow distribution. It is clarified that the suction performance is affected by the velocity distortion, especially in the circumferential direction, and the incipient cavitation is related with the local incidence angle of the impeller blade.