切割叶轮对离心泵性能影响的数值模拟分析

CFD Analysis on Effects of Impeller Trim in Centrifugal Pump

基于CFD计算软件Fluent,对某低比转速离心泵在切割叶轮前后的内部流场进行了叶轮和蜗壳的耦合数值模拟。根据数值模拟的结果,预测了切割叶轮后离心泵的性能曲线,并分析了叶轮外径变化对泵内部流场的影响。分析表明:随着叶轮外径的减小,泵的扬程和轴功率都有所下降;效率在切割量较小时有所上升,随着外径的减小而下降。利用模拟结果得到的切割指数与已有的切割定律有所不同。叶轮外径变化后,叶轮进口处的静压分布基本未变,叶轮出口处及蜗壳内的压力分布出现了变化。

Based on CFD software Fluent,the flow field of a low specific speed centrifugal pump was simulated in the case of different impeller outlet diameters.According to the simulation results,the pump’s characteristic curve was acquired and inner flow field affected by the change impeller diameter was analyzed.Studies shows that head and axis power descends when diameter of the impeller minish,while the efficiency rises a little in small cutting quality and descends in large cutting quality.Trim index calculated from the simulation results is slightly different with the now adopted trim law.The change of impeller outlet diameter has obvious effects on static pressure at impeller outlet and in volute.