Effect of stay vane angle on the performance of hydraulic turbine.

Abstract

The effects of stay vane angle on the turbine efficiency performance was investigated with a tandem circular cascade comprising stay vanes and wicket gates of a high specific speed Francis turbine. The velocity distributions around the stay various and wicket gates as wall as the variation of angular momentum along the streamline were calculated with the Flow analysis computer program based on the quasi-three dimensional Flow theory for the various combination of the stay vane setting angle and the wicket gate opening. A model Francis turbine having the same configurations of stay vane and wicket gate as those analyzed numerically was tested to measure the turbine efficiency and compare with the results of slow analysis. The measured results showed a good correlation with the calculated results and it made clear that the angle of stay vane affects the turbine efficiency in the region of large wicket gate opening.