基于VOF模型的抽水蓄能电站全过流系统水轮机工况数值模拟

Numerical simulation of full flow system of pumped storage power station under turbine conditions based on VOF model

为了更加全面地分析抽水蓄能电站水轮机工况的流动特性,建立包括引水隧洞、调压井、高压管道、水泵水轮机以及尾水隧洞的全过流系统几何模型,采用两相流VOF模型对不同导叶开度的水轮机工况进行三维湍流数值模拟,计算各过流部件的水力损失,并详细分析了机组段流场。结果表明:抽水蓄能电站的水力损失主要发生在机组段,而输水系统的水力损失相对较小,约占总水力损失的18.6%;导叶开度不同从而引起叶片压力面与吸力面的压力差不同,这是导致转轮水力损失不同的主要原因;尾水管内的流态与导叶开度有关,开度越小,在尾水管进口处越容易形成回流,水力损失越大。

In order to comprehensively investigate the flow characteristics at a pumped storage power station under turbine conditions , we established a geometric model of the full flow system including the diversion tunnel , the surge tank , the high-pressure pipes , the pump-turbine group , and the tailrace tunnel .Based on the VOF model , we conducted three-dimensional numerical simulation of turbulent flow under turbine conditions with different guide vane opening degrees , calculated the hydraulic loss of each flow part , and analyzed the flow field of the pump-turbine unit in detail .The results show that the hydraulic loss mainly occurred in the pump-turbine unit of the station , and it was small in the water transfer system , accounting for about 18.6% of total hydraulic loss .The difference in the runner ’ s hydraulic loss was mainly due to the pressure difference of the surface of two sides of the blade caused by different guide vane opening degrees .The flow pattern of the tailrace tunnel was related to the guide vane opening degree , and the smaller the degree of opening was , the more chance for the backflow to occur in the draft tube , and the greater hydraulic loss .