Analysis of Internal Flow Characteristics of a Startup Pump Turbine at the Lowest Head under No-Load Conditions

Journal of Marine Science and Engineering

Mabing Ni¹  Xi Wang¹  Zhengwei Wang²  Chunan Yang²  Wei Wang² 

[1] Anhui Jinzhai Pumped Storage Power Co., Ltd., Lu’an 237333, China;Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China;

关键词: pump turbine;    no-load condition;    pressure pulsation;    axial water thrust;    numerical simulation;   

DOI  :  10.3390/jmse9121360

来源: DOAJ

【 摘 要 】

The instability of the no-load working condition of the pump turbine directly affects the grid connection of the unit, and will cause vibration and damage to the components of the unit in severe cases. In this paper, a three-dimensional full flow numerical model including the runner gap and the pressure-balance pipe was established. The method SST k-ω model was used to predict the internal flow characteristics of the pump turbine. The pressure pulsation of the runner under different operating conditions during the no-load process was compared. Because the rotation speed, flow rate, and guide vane opening of the unit change in a small range during the no-load process, the pressure pulsation characteristics of the runner are basically the same. Therefore, a working condition was selected to analyze the transient characteristics of the flow field, and it was found that there was a high-speed ring in the vaneless zone, and a stable channel vortex was generated in the runner flow passage. Analyzing the axial water thrust of each part of the runner, it was found that the axial water thrust of the runner gap was much larger than the axial water thrust of the runner blades, and it changed with time periodically. It was affected by rotor stator interaction. The main frequency was expressed as a multiple of the number of guide vanes, that is, vanes passing frequency, 22f_n. During the entire no-load process, the axial water thrust of the runner changed slowly with time and fluctuated slightly.

【 授权许可】

Unknown