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本文充分考虑不可凝结气体、表面张力、压力脉动和湍动能的影响,对空化模型进行了修正。利用修正了的空泡质量传输方程,对某电站水轮机模型机的空化现象进行了数值模拟,并与实验结果进行了对比。从空泡体积分布、效率与空泡数的关系验证了空化模型的合理性。转轮叶片表面上的压力分布在非空化和空化两种工况下进行了对比分析。小流量工况下转轮叶片进口边的流动分离导致了转轮叶片头部的压力分布曲线的扭曲,并与转轮叶片上空化的发生存在一定联系。
In this paper, the effects of uncondensable gas, surface tension, pressure pulsation and turbulent kinetic energy are fully considered and the cavitation model is modified. The cavitation phenomenon of turbine model machine of a hydropower station is numerically simulated with the modified mass transfer equation and compared with the experimental results. The rationality of the cavitation model is verified from the relationship between the volume distribution of void cells, the efficiency and the number of cavities. The pressure distribution on the surface of the rotor blade was compared and analyzed under both non-cavitation and cavitation conditions. The flow separation at the inlet side of the runner vanes under small flow conditions leads to the distortion of the pressure distribution curve at the rotor vane head and is related to the occurrence of cavitation on the runner vanes.