S形下卧式轴伸贯流泵装置叶片区压力脉动特性研究

为研究S形下卧式轴伸贯流泵装置叶片区压力脉动特性,采用非定常CFD方法对不同工况时泵装置进行了全流道三维非定常流场数值计算,通过在叶片区设置监测点以获得叶片区关键位置的压力脉动数据,并进行频谱分析。通过与实测泵装置扬程和效率对比,证明该方法能较准确地反映泵装置内部非定常流动特征。研究表明:高效工况和大流量工况时,转轮进口和出口的脉动幅值从轮缘向轮毂侧逐渐减小,小流量工况时未呈现该规律,各工况时转轮进口和出口脉动主频受叶频控制。流量系数KQ在(0.368~0.552)范围内转轮进口处同一监测点的压力脉动幅值随流量增大而降低,转轮与导叶体间的脉动幅值随流量的增加先减小后增大,在高效工况附近脉动相对最小。导叶体出口的压力脉动主频受叶频的影响较小,未与导叶体叶片数成规律。

Pressure Pulsations of the Blade Region in S-shaped Shaft-extension Tubular Pumping System

In order to research pressure fluctuation of unsteady flow in S-shaped shaft extension tubular pumping system,the unsteady CFDmethod is used to simulate the 3D unsteady flow field of pumping system at 3 different operating conditions. Somemonitor points were set at the key positions of blade region for getting the change of pressure pulsations,and the data were used to time-domain analysis and spectrum analysis. The predicted head and efficiency were validated by the comparison with the tested results,and the comparison result shows that the unsteady flow characteristic of pumping system can be simulated by thismethod.The pulsating amplitude decreases gradually from the shroud to hub in high efficiency and large flow rate conditions for the inlet and outlet of impeller,while the change law of pulsating amplitude is not the same with that at the small flow rate condition. Themain frequency is dominated by the impeller rotation speed and the blade numbers for the inlet and outlet of impeller in different conditions. With the increase of flow coefficient,the pulsating amplitude decreases for the samemonitor point at the impeller inlet,while the pulsating amplitude decrease firstly then increase between the impeller and guide vane,and the pulsating amplitude is least at the high efficiency condition. The rotation speed of impeller has little effect on themain frequency at the outlet of guide vane.