不同级数电潜泵失速演化及级间差异性研究

Stall Evolution and Inter-stage Difference Characteristics of Electric Submersible Pumps with Different Stages

当电潜泵在小流量工况下运行时会出现失速现象,并出现一系列的负面影响,严重影响机组的安全性和稳定性。为了研究失速工况下电潜泵内部的旋涡演化及其级间差异性,文中对单级、两级和三级电潜泵进行数值模拟研究,重点讨论了设计工况、临界失速及深度失速工况下电潜泵的内外特性。结果表明:在设计工况和临界失速工况下,首级叶轮流道内部出现多个旋涡结构,次级与末级叶轮内流动顺畅。在深度失速工况下,单级、两级和三级电潜泵首级叶轮内部均存在着大尺度的回流涡,并伴随着强烈跨流道溢流现象;流道内部各种旋涡聚集糅杂形成涡团,对流道出口处产生严重阻塞。电潜泵首级叶轮进口处大尺度旋涡结构、各级叶轮同步失速以及导叶内强烈的分离涡共同导致扬程骤降,同时造成极高的能量损失。该研究为完善电潜泵设计方法提供了理论基础。

When the electric submersible pump(ESP)operates under low flow conditions,it may experience stall and a series of negative effects,seriously affecting the safety and stability of the unit.In order to study the vortex evolution and inter-stage differences within the ESP under stall conditions,this paper conducts numerical simulation research on one-stage,two-stage and three-stage ESPs,focusing on the internal and external characteristics of the ESP under design conditions,critical stall conditions,and deep stall conditions.The results show that under design and critical stall conditions,multiple vortex structures appear inside the flow channel of the first-stage impeller,and the flow inside the secondary and final-stage impellers is smooth.Under deep stall conditions,large-scale reflux vortices are inside the first-stage impeller of one-stage,two-stage and three-stage ESPs,accompanied by a strong cross-channel overflow phenomenon.Various vortices inside the flow channel gather and mix to form vortex clusters,causing a serious blockage at the flow channel outlet.The large-scale vortex structure at the inlet of the first stage impeller of an ESP synchronous stall of all stages of the impeller,and strong separation vortices in the diffusers jointly lead to a sudden drop in the head,while causing extremely high energy loss.This study provides a theoretical basis for improving the design method of electric submersible pump.