Study on High Speed and High Head Reversible Pump -Turbine

Abstract

In this paper, improvement of hydraulic performance, particularly pressure fluctuation and cavitation, in order to speed up the runner revolution for a pump-turbine of 500m head class, is numerically and experimentally studied. High speed design of a pump-turbine offers an economical merit, because the size of the pump-turbine and generator-motor can be made smaller and the efficiency is improved. However, there are some problemes to be solved in order to develop a high speed pump-turbine. The first one is the increase of pressure fluctuation of runner outlet at partial load turbine operation. The second one is the deterioration of cavitation performance at pump operation. The third one is the increase of stress and vibration for runner. In order to overcome these problemes, the optimization of runner shape is carried out at design stage by using numerical simulation and its results are experimentally verified.