不同叶轮在轴流泵装置中的水力特性分析

An Analysis of the Hydraulic Characteristics of Different Impellers in Axial-flow Pump Devices

为了研究不同叶轮在同一泵装置中的水力性能,基于某立式泵装置,选取两副性能相近的轴流泵叶轮,采用数值模拟方法分析了两副叶轮在同一泵装置中的流动状况,并通过模型试验测试了泵装置的外特性。根据数值模拟和模型试验结果,在扬程相同的情况下,比较了各自设计工况时两副叶轮叶片表面的压力分布情况;对比了多个工况时不同测点位置的压力脉动值和叶轮导叶内部的流速矢量图;分析了叶轮对其他部件的影响。数值模拟结果表明:为了满足泵装置设计要求,不同的叶轮运行条件不同;在各自对应的设计工况下,两副叶轮的叶片表面压力分布差异明显;叶片头部的压差是造成叶轮进口压力脉动幅值大的原因,导叶内部出现漩涡导致导叶内部低频压力脉动突出;导叶出口的流速分布不均匀度与出水流道的水力损失变化趋势一致。模型试验结果表明:在设计工况,两副叶轮对应的泵装置效率基本相同,而空化性能差异较大;数值模拟与模型试验结果吻合较好,验证了数值模拟的可靠性。

In order to study the hydraulic performance of different impellers in the same pump device,two pairs of axial-flow impellers with similar performance are selected based on a vertical pump device.The flow conditions of two pairs of impellers in the same pump device are analyzed by numerical simulation method,and the external characteristics of the pump device are tested by the model test.According to the results of numerical simulation model test,the pressure distribution on the surface of two impeller blades under the same head is compared.The pressure pulsation values at different measuring points and the flow velocity vector diagrams inside the impeller guide vane are compared under multiple working conditions,the influence of impeller on other flow parts is also analyzed.The numerical simulation results show that to meet the design requirements,different impeller running conditions are different.Under the corresponding design conditions,the pressure distribution on the blade surface of the two impellers is obviously different.The pressure difference at the blade head is the reason for the large amplitude of pressure pulsation at the impeller inlet,the vortex in the guide vane blade leads to the prominent low-frequency pressure pulsation in the guide vane blade,the velocity distribution inhomogeneity of guide vane outlet is consistent with the hydraulic loss of outlet passage.The model test results show that the pump efficiency of the two impellers is basically the same,but the cavitation performance is dif‐ferent.The numerical simulation results agree well with the model test results,which verify the reliability of the numerical simulation.