空间导叶式多级离心泵级间能量损失机理

Energy loss mechanism in inter-stage of multi-stage centrifugal pump with space guide vane

为探究空间导叶式多级离心泵级间能量损失的原因,以1个单级和1个3级潜水泵为研究对象,通过试验和数值模拟相结合的方法,分析其级间能量损失的机理.对单级和3级潜水泵分别进行全流场外特性试验.基于ANSYS软件对3级潜水泵不同流量点进行数值模拟和内流场分析,着重对各级叶轮进口流态、内部旋涡结构和叶片载荷分析比较.结果表明:小流量工况下,3级潜水泵各级扬程接近且与单级扬程相差不大;额定流量工况和大流量工况下,3级潜水泵第1级扬程与单级扬程仍相差不大,但后2级扬程相比于第1级降低了6%~10%.随着流量的增大,首级叶轮来流稳定性不受影响,其后各级叶轮进流流态变差.后2级叶轮进口液体介质冲角变化使其对叶片进口边的冲击增大.后2级叶轮进口处的涡在流量较大时发展为流向涡,从而引起叶片载荷突变,削弱了叶轮做功能力,导致后2级能量损失.研究结果可为多级离心泵的设计提供理论依据.

In order to investigate the causes of inter-stage energy loss in a multi-stage centrifugal pump with space guide vane,a single-stage and a three-stage submersible pump were taken as research objects,and the mechanism of inter-stage energy loss was analyzed through a combination of experimental and numerical simulation methods.Full flow field hydraulic characteristic tests were carried out on the single-stage and three-stage submersible pumps,respectively.Based on ANSYS software,numerical simulation and internal flow field analysis were conducted for different flow points of the three-stage submersible pump,with a focus on analyzing and comparing the inlet flow pattern,internal vortex structure,and blade load of each stage of the impeller.The results show that under low flow conditions,the heads of each stage of the three-stage submersible pump are close and not significantly diffe-rent from that of the single-stage.Under rated flow conditions and high flow conditions,the first-stage head of the three-stage submersible pump is still not significantly different from that of the single-stage head,but the head of the last two stages is 6%-10%lower than that of the first stage.As the flow rate increases,the stability of the incoming flow from the first-stage impeller is not affected,while the flow state of the incoming flow from the subsequent stages of impellers deteriorates.The change in the angle of attack of the liquid medium at the inlet of the last two stages of the impeller increases its impact on the inlet edge of the blades.When the flow rate is high,the vortices at the inlet of the last two stages of the impellers develop into streamwise vortices,causing a sudden change in blade load which weakens the impeller′s functional ability,resulting in energy loss in the last two stages.The research results can provide a theoretical basis for the design of multi-stage centrifugal pumps.