1. Chongqing Panlong Pumped Storage Co., Ltd., Chongqing 401452, China; 2. Department of Mechanical and Electrical Engineering, Wenzhou University, Wenzhou, Zhejiang 325035, China; 3. Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China; 4. Key Laboratory of Fluid Machinery and Engineering(Xihua University), Sichuan Provience, Chengdu, Sichuan 610039, China
Abstract：In order to study the influence of the rotational speed of the pump-turbine on the flow cha-racteristics of water-ring under the phase modulation condition, the ANSYS CFX software is used to simulate the unsteady flow characteristics of water-ring with medium-specific speed pump-turbine. The pressure fluctuation and internal flow characteristics of the water-ring are analyzed with rotation speed of 600, 800, 1 000 and 1 050 r/min. The results show that the thickness of the water-ring in the vaneless zone is closely related to the rotating speed. The larger the rotating speed is, the large average radius of the free surface in the water-ring is, and the thinner the thickness of the water ring is. The composition pressure fluctuation frequency in the vaneless zone were the same at different rotational speeds, and the dominate frequency is 7fn, which caused by the interaction between rotor and stator. The amplitude of the dominate frequency increases with the increase of the rotating speed as well. The intensity of pressure fluctuation is almost the same in the circumferential direction. However, the pressure fluctuation becomes smaller as the location closer to the runner in the radial direction. There is an obvious gas-liquid interface near the runner outlet and the runner passage filled with air, which shows that the water-ring has a good effect on gas sealing. The research results can provide some reference for the operation of pump turbine under phase regulation condition.
