潜水轴流泵内部流场压力脉动的数值模拟

流场压力脉动对轴流泵的运行稳定性具有重要影响,为了准确分析潜水轴流泵的压力脉动特性,采用RNG k-ε湍流模型和SIMPLEC算法,对ZQA系列潜水轴流泵进行了全流道三维流动数值模拟和压力脉动分析.计算结果表明：轴流泵的扬程、功率、效率等外特性计算结果与试验结果基本吻合;轴流泵内部叶轮进口截面压力脉动幅值最大,泵内的压力脉动的主要频率与叶片通过频率相同,导叶后的脉动以低频为主,叶片表面从轮毂到轮缘压力脉动低频成分逐渐减少;在叶片工作面,压力脉动的幅值从轮缘到轮毂逐渐减小,从叶轮进口到出口逐渐增大.叶片进水边轮缘处压力脉动的幅值是轮毂处的1.22倍.在叶片背面,叶片进水边轮缘处压力脉动的幅值是轮毂处的1.77倍,出水边轮缘处压力脉动的幅值是轮毂处的0.92倍,叶片背面的压力脉动幅值明显小于工作面;叶轮进口截面,在0.8Q工况流量下压力脉动最大,为设计工况的2倍.计算结果为进一步分析轴流泵压力脉动提供了参考.

Numerical analysis of pressure fluctuation of internal flow in submersible axial-flow pump

The pressure fluctuation in flow field has important influence on the operation stability of axial-flow pumps. In order to precisely analyze the pressure fluctuation in submersible axial-flow pumps, the RNG k - ε turbulence model and SIMPLEC algorithm were adopted to investigate the three dimensional turbulent flow and the pressure fluctuation in an axial-flow pump. The calculated results show that the predicted performance curves of pump were in good agreement with the experiment. The maximum amplitude of the pressure fluctuation occurs at the inlet of the impeller, and the main frequency of the pressure fluctuation inside the pump is the same as the blade passing frequency when the pressure fluctuation behind the guide-vanes is dominated by low-frequency. From hub to tip of the blade surface, the low frequency components of the fluctuation decreases . On the pressure surface of the blade, the pressure fluctuation amplitude decreases from tip to hub and increases from inlet to outlet of the impe-ller. The fluctuation amplitude on the outer tip is 1.22 times higher than that on the hub at the inlet. On the suction surface, the pressure fluctuation amplitude on tip is 1.77 times of the hub at the inlet and is 0.92 times of the hub at the outlet of the impeller. The amplitude on the suction surface is significantly less than that on the pressure surface of the blade. At the inlet of the impeller, the maximum amplitude of the pressure fluctuation happens at 0.8Q flow rate which is about twice the value at the design flow rate. The above-simulated results can provide some references for further analyzing the pressure fluctuation of axial-flow pumps.