Author(s): Xiaolong Fu; Jingwei Lv; Deyou Li; Hongjie Wang; Daqing Qin; Xianzhu Wei

Linked Author(s): Deyou Li

Keywords: Pressure fluctuation; Ultra-high head pump-turbine; Turbine runaway; Backflow; Water hammer; Impeller optimization

Abstract: Pressure fluctuation (PF) is a serious issue in transitions of the ultra-high head (UHH) pump-turbines (PTs). To explore the mechanism and control method of PF, the turbine runaway process (TRP) of an UHH PT was simulated using the one- and three-dimensional coupled method. The study suggested that the local backflow (BF) near the high-pressure (HP) inlet of the impeller blocked the impeller channel and induced water hammer. The local BF near the HP inlet of the impeller were closely related to the ratio of rotational speed to PT head. To suppress the BF this study proposed an improved impeller channel with 5 degree spread angle in meridian plane. The study found that the increase of rotational speed and transient pressure variations induced by water hammer could be suppressed successfully by using the improved impeller. The study provided important reference for the design and optimization of the UHH PTs.

DOI: https://doi.org/10.1088/1742-6596/2752/1/012057

Year: 2023