离心泵前盖板小叶片抑制空化效果的研究

Research on Cavitation Suppression Effect of Tiny Blade in the Shroud of Centrifugal Pump

以一台低比转速离心泵为研究对象,提出了一种在离心泵前盖板布置非连通小叶片结构来抑制空化的方法,并设计4种方案进行研究。利用ANSYS CFX进行数值模拟,并与试验结果进行对比,选出较优方案与原模型进行流线、湍动能、压力、空泡和压力脉动的对比分析。结果表明:在叶轮前盖板布置小叶片,可诱发叶轮进口附近相对高压,减缓低压区扩散并梳理了流场结构,对空化产生抑制作用;在较优位置添加小叶片后,对泵外特性影响较小,并降低了临界空化余量,提高了断裂扬程;在空化初生和发展阶段,小叶片降低了流道内旋涡强度,优化了流场结构。在空化严重阶段,小叶片加强了旋涡强度;在各空化余量下,小叶片降低了压力脉动幅值,使泵运行更加稳定。

A low specific speed centrifugal pump was used as a research object, and a method to suppress cavitation by arranging a non-connected tiny blade structure on the shroud of the centrifugal pump was proposed, and four schemes were designed for the study. Numerical simulations were performed using ANSYS CFX and compared with the experimental results, and the better scheme was selected for comparative analysis of flow lines, turbulent kinetic energy, pressure, cavity volume and pressure pulsations with the original model. The results show that the arrangement of tiny blades on the shroud of the impeller can induce relatively high pressure near the impeller inlet,slow down the diffusion of the low-pressure region and comb the flow field structure, which has a suppressive effect on cavitation. The addition of tiny blades in the better position has less effect on the external characteristics of the pump and reduces the critical cavitation margin and increase the breaking head. During the initial and developmental stages of cavitation, the tiny blades reduce the intensity of vortices in the flow channel and optimize the flow field structure. During the cavitation severe stage, the tiny blades strengthen the vortex intensity;under each cavitation margin, the tiny blades reduce the pressure pulsation amplitude, making the pump operation more stable.