基于直接边界元法的潜水排污泵内流噪声数值模拟

为了揭示不同湍流模型对超厚叶片潜水排污泵流动特性及噪声的影响,以1台超厚叶片低比转数潜水排污泵为模型,基于CFD理论与Lighthill声比拟理论,对潜水排污泵的流场和声场进行数值模拟,并对不同工况下(0.6Q_N,0.8Q_N,1.0Q_N,1.2Q_N,1.4Q_N)潜水排污泵的内部压力分布特性进行分析,同时探讨了内声场和外声场的噪声产生原因及分布传播特性.数值模拟结果表明,采用SST模型得到的性能曲线最接近试验结果;当叶轮从时刻a旋转到时刻d时,隔舌附近的高压区增大;隔舌处压力脉动最剧烈,这说明隔舌处是主要噪声源;在最优工况附近噪声较小,偏离最优工况处噪声较大;噪声极大值均出现在30°~75°内,极小值在225°~250°内.

Numerical simulation of internal flow-induced noise in submersible sewage pump based on the direct boundary element method

In order to reveal the influence of the different turbulence models on the flow characteristics and noise in the submersible sewage pump, a low specific speed pump with ultra-thick blades was adopted as a model. The computational fluid dynamics(CFD)based on the Lighthill equation theory was adopted to calculate the flow field and sound field respectively. The pressure distribution at different flow rates of 0.6Q_N, 0.8Q_N, 1.0Q_N, 1.2Q_N, 1.4Q_N was analyzed, and the causes of noise generation and distribution characteristics in the inner and outer fields were discussed. The results show that the performance curve obtained by SST model is the closest to the test results. When the impeller rotaties from moment a to moment d, the high-pressure area near the tongue increases. The pressure fluctuation at tongue is the most dramatic, indicating that the tongue is the main noise source. The noise is lower near the optimal condition and the larger noise deviates from the optimal condition; The maximum noise appears at 30°-75°, the minimum value oppears at 225°-250°.