高比转速斜流泵内部非定常压力脉动特性

摘要

In order to investigate the pressure fluctuation induced by the rotor-stator interactions of the mixed-flow pump,the standard turbulent k-ε model and SIMPLEC algorithm were applied to simulate the unsteady flow in a high-specific-speed mixed-flow pump.The pressure fluctuations at four representative locations under multi-conditions were obtained, and the time-domain and frequency-domain of each monitoring point were analyzed.Comparison of calculated steady flow head and efficiency with the test results verified that the inner flow characteristic simulated by this calculation method was comparatively accurate.The numerical results showed that the maximum pressure fluctuation appeared at impeller inlet where the pressure coefficient amplitude increased gradually from hub to rim; the fluctuation at impeller inlet became stronger with the deviation of flow rate from design point and the relative fluctuation at 0.7Qopt was about 0.5 time stronger than that at the design flow rate.The frequency domain transformed by Fast Fourier Transform (FFT) showed that the dominant frequency was approximate to the blade passing frequency.The numerical results can provide certain theoretical references to reveal the pressure fluctuation in the mixed-flow pump.%为了研究斜流泵叶轮和导叶的动静相干作用引起的内部压力脉动特性,该文基于标准k-ε模型,采用SIMPLEC算法和滑移网格技术,对高比转速斜流泵进行非定常数值模拟,分析了不同工况下的叶轮进出口、导叶中部和导叶出口等位置的压力脉动的时域和频域特性.通过定常计算的扬程、效率值与试验值进行对比,证明该计算方法和网格可以较准确地反映斜流泵内的流动特性.计算结果表明,斜流泵最大压力脉动发生在叶轮进口前,泵运行偏离最优工况越远,叶轮进口处压力系数幅值越大,在0.7Qopt工况时叶轮进口监测点PO3的压力系数幅值约为最优工况的1.5倍;压力脉动主频为叶轮叶片通过频率.研究成果为揭示斜流泵内部压力脉动规律提供了一定的理论参考.