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采用RNGk-ε模型、Realizable k-ε模型、Transition SST模型和DES模型,在4种网格尺度下对模型混流式水轮机三维全流道非定常湍流进行模拟.在试验验证的基础上,分析各模型对水轮机压力脉动模拟的适应性,并进行网格无关性分析.分析结果表明:4种湍流模型都可以模拟出尾水管偏心涡带的形态,但尾水涡带在相位上不同,压力脉动的主频或振幅有差别;湍流模型与网格尺度不是单调线性关系,甚至相反;Transition SST模型比RNGk-ε模型、Realizable k-ε模型、DES模型对水轮机压力脉动模拟的适应性更好,在不同网格尺度下预测的压力脉动主频、振幅和试验结果更加吻合.
Using RNGk-ε model, Realizable k-ε model, Transition SST model and DES model, the three-dimensional full-channel unsteady turbulence of a Francis turbine is simulated under four grid scales. Based on the experimental verification, The model is adaptable to the pressure pulsation simulation of the turbine and the grid-independent analysis is carried out. The analysis results show that all four kinds of turbulence models can simulate the shape of the eccentric vortex in the draft tube. However, the wake vortex is different in phase and pressure pulsation The frequency and amplitude of turbulence model are different from those of grid scale. The turbulence model is not monotonous linear relationship with the grid scale, and even the contrary. Transition SST model has better adaptability to pressure pulsation simulation of hydraulic turbine than RNGk-ε model, Realizable k-ε model and DES model, The predicted frequency pulsations at different grid scales are more consistent with the experimental results.