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为预测低比转速混流式水轮机的主要流动噪声,采用重整化群RNGκ-ε模型和FW-H模型,计算了不同导叶与转轮叶片径向间距时水轮机导叶与转轮壁面上压力脉动构成的偶极子声源产生的流动噪声,分析了导叶与转轮叶片径向间距对水轮机压力脉动及噪声特性的影响,以及压力脉动与流动噪声之间的关系。结果表明,导叶末端和转轮叶片进口背面压力脉动最剧烈,是主要的偶极子噪声源,压力脉动和流动噪声的离散噪声在叶频及其谐频处出现峰值;随导叶与转轮叶片径向间距增大,压力脉动幅值减小,流动噪声减小,因此适当增大水轮机导叶与转轮叶片径向间距是一种有效降低流动噪声的途径。
In order to predict the main flow noise of Francis turbine with low specific speed, RNGκ-ε model and FW-H model of renormalization group were used to calculate the pressure The effect of pressure pulsation and flow noise on the pressure pulsation and noise characteristics of turbine is analyzed. The relationship between pressure pulsation and flow noise is analyzed. The results show that the pressure pulsation at the tip of the guide vane and the inlet of the rotor blade is the most severe, which is the main source of dipole noise. The discrete noise of pressure pulsation and flow noise appears the peak value at the leaf frequency and its harmonic frequency. The radial distance between the blades increases, the amplitude of the pressure pulsation decreases and the flow noise decreases. Appropriately increasing the radial distance between turbine guide vane and rotor blade is an effective way to reduce the flow noise.