关键词: 输水系统稳定性, 明满过渡流, 尾水隧洞, 数值模拟, 白鹤滩水电站

Abstract: Baihetan Hydropower Station is the world′s second largest hydropower station with installation capacity of 16000 MW. The stability of the diversion and power generation system is very important for the operation of the whole power station. The free-pressure transition flow in the tailrace tunnel influences the stability of the diversion and power generation system seriously. In this paper, the effects of different flow states in the tailrace tunnel on the unit stability and water level fluctuation in the tailrace surge chamber are studied by the characteristic implicit scheme virtual slit method. The results show that the open channel flow in the tailrace tunnel can accelerate the stability of water level fluctuation in surge tank, which is conducive to the diversion system stability; however, for the free-pressure transition flow, the pressure fluctuation will worse the unit′s stable regulation quality, which is unfavorable to the diversion system stability; the length of the free-pressure flow section has little effect on the regulation quality of the unit and the length selection is not limited by the diversion system stability. The results may provide reference for the design and research of similar water diversion system.

Key words: operation stability, free-surface transition flow；tailrace tunnel；numerical simulation；Baihetan Hydropower Station