Aeration valve improvement of Liziping hydropower plant Francis turbine
ZHOU Tao, ZHANG Hai-Ku, ZHU Xiao-Min, LIU Xiao-Bing, LIU De-Min, DENG Ming-Gui
(1.Guodian Sichuan Liziping Electric Power Co.,Ltd.,Yaan， Sichuan 625400, China; 2.Commissioning and Test Institute of Sichuan Electric Power Industry, Chengdu， Sichuan 610072, China; 3.School of Energy and Environment, Xihua University, Chengdu， Sichuan 610039, China; 4.Dongfang Electric Corporation, Chengdu, Sichuan 611731, China)
Abstract For Francis turbine, reasonable aeration can weaken vibration and cavitation effectively. The high head turbine of Liziping hydropower plant originally uses holes at turbine bearing flange root to aerate, and which can not have expected function for the whirl area and causes significant vibration. A project of setting cross aeration valve in draft tube is proposed. To prevent the device from falling off and reduce flow resistance and lower whirl whip reaction, the streamline shaped cross aeration was made of highquality stainless steel and had compensating holes placed in the center and back of it. According to the comparison of the vibrations, pressure fluctuations and air admission test before and after the modification, the results show that it can exactly and automatically supply air to the strong vibration region, effectively eliminate pressure fluctuation caused by draft tube whirl whip, the vibration of bearing, brackets and cover are reduced to different degrees respectively, and the draft tube cone swing completely solved. It works well for the stability of hydroelectricity generating units. For other small and mediumsized hydroturbine plants, the aerating device design is referentially valuable.
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