进口引流结构对高速离心泵空化性能的影响

Effect of Inlet Drainage on Cavitation Performance of High-speed Centrifugal Pumps

为提高高速离心泵空化性能,探究增加进口引流结构对高速泵空化性能的影响,该文基于正交试验设计方法对进口引流结构几何参数进行了方案设计,采用SST k-ω湍流模型、Z-G-B空化模型对各方案进行了数值仿真和分析。研究结果表明:相较于初始方案,增加进口引流结构后,高速离心泵扬程有较明显提升,叶轮空泡率最大降低39.7%,空化性能得到改善;进口引流结构环形架内径对泵空化性能影响程度最大,设置导流板可有效改善进口圆周速度分布。通过与初始方案的水力性能和空化特性进行对比,分析确定了最优方案。最优方案的紊流度显著减小,泵扬程增加9.62m,泵效率提升2.4%,必需汽蚀余量减小2.20 m。引流结构可显著减少回流引起的能量损失,保证进口的流动均匀性是提升高速离心泵空化性能的关键途径。

In order to improve the cavitation performance of high-speed centrifugal pump,the influence of increasing inlet drainage structure on the cavitation performance of high-speed pump is investigated in this paper.Based on the orthogonal experimental design method,the geometric parameters of the inlet drainage structure are designed.The SST k-o turbulence modei and Z-G-B cavitation model are used to simulate and analyze each scheme.The results show that compared with the initial scheme,the head of the high-speed centrifugal pump is obviously improved after the inlet drainage structure is added,and the cavitation rate of the impeller is reduced by 39.7%at most,which means the cavitation performance is improved.The inner diameter of the annular frame of the inlet drainage structure has the greatest influence on the cavitation performance of the pump,and the setting of the guide plate can effectively improve the circumferential velocity distribution of the inlet.The optimal scheme is determined by comparing the hydraulic performance and cavitation characteristics with the initial scheme.The turbulence degree of the optimal scheme is significantly reduced,the pump head is increased by 9.62 m,the pump efficiency is increased by 2.4%,and the necessary cavitation margin is reduced by 2.20 m.The energy loss caused by the backflow can be significantly reduced by the drainage structure.Ensuring the flow uniformity of the inlet is the key way to improve the cavitation performance of the high-speed centrifugal pump.