Abstract
In order to clarify the instability phenomena when the pump-turbine stops in case of necessity, the experiment and the numerical simulation were performed. The past research shows that these phenomena occur when the characteristic curve observed is the serpentine curve. Also, the inlet height and the outlet height of the pump-turbine's runner has no effect on this result. Therefore, this research focuses on how the inlet and blade angle of the guide vanes affects the characteristic curve observed when the blade thickness of pump turbine's runner is changed. Three different inlet and blade angles are used for the experiment and the numerical simulation. As a result, they show that the instability of the pump turbine is decreased by the guide vanes. Besides, the numerical simulation shows the vortex occurs at the trading edge of the runner.
