Rotating Stall Characteristics in Off Design Condition of a Centrifugal Pump

Abstract

Downsizing and improvement of efficiency in a centrifugal pump have been required still now. It is well known that the flow instability such as a positive slope in Q-H curve, rotating stall often may appear in case of the above advanced design. Though a lot of studies of flow instability in a pump were carried out by experimental and computational approaches up to now, this generating mechanism was not clarified quantitatively.

In this study, we made the one stage model test facility for measuring both the performance and the internal flow. By use of this test facility, we found the rotating stall in the diffuser influences the positive slope mechanism in Q-H curve. The characteristics of the rotating stall were clarified by experiments and computations. The simulation results have good agreement with the experiments quantitatively.