离心泵进口回流特性的CFD与试验研究

Research on the Inlet Recirculation's Characteristics in Centrifugal Pumps Based on CFD and Experiment Methods

为研究离心泵进口回流的流场特性及其流动规律,针对IS65-50-160低比转速离心泵,运用定常数值计算与大涡模拟方法,且采用正则化螺旋度分析法对离心泵进口回流漩涡的涡核强度进行分析,最后对模型泵进行了试验研究。研究结果表明:离心泵发生进口回流的初始流量为0.6Qd,并随着流量的减小回流逐渐变强;叶轮一个旋转周期内叶轮流道进口处各监测点的压力脉动都有6个波峰和波谷,靠近叶片吸力面监测点幅值最大,且漩涡的涡核强度变化可以分为发展、衰减、再次发展、保持、衰减五个阶段;通过进行压力脉动测试试验,研究得到进口管监测点处的压力脉动主要以6倍轴频、12倍轴频为主,在流量低于0.6Qd时,幅值相差较小,当流量增加到0.7Qd时,幅值明显减小。

In order to study the inlet recirculation＇s characteristics and flow patterns in a centrifugal pump, a low specific speed cen- trifugal pump named IS65-50-160, is investigated based on the LES and experiment methods. Meanwhile, the regularization method of Heli City is applied to analyze the vortex core strength distributed on the section-cross of the impeller. The results show that： the onset of the recirculation in the pump inlet is at a critical flow rate of 0. 6Qd. As the flow rate decreases, the size and the intensity of the recirculation vortex increase. During one rotating cycle of the impeller, there are six peaks in the pressure fluctuation of the mo- nitoring points in the impeller inlet. The maximum amplitude of the pressure fluctuation occurs near the blade suction surface. More over, the vortex experiences a whole process of developing, decreasing, developing, holding and decreasing. With respect to the ex- perimental analysis, it can be concluded that the domain frequencies of pressure fluctuations in the inlet pipe are 6 fn （rotating shaft frequency） and 12 fn. As the flow rate is lower than 0. 6Qd, the amplitude of the pressure fluctuation shows a sma[1 change, while the intensities of pressure fluctuation become obviously weakened as the flow rate increases.