导叶出口边位置对井用潜水泵性能的影响

为研究空间导叶出口边位置对井用潜水泵性能的影响规律，该文针对250QJ125型5级井用潜水泵，在其他几何参数均给定的条件下，通过沿轴向改变原始导叶的出口边位置，使其既满足与旋转轴线垂直又与半径线重合，设计了6个模型方案。基于雷诺时均N-S方程和RNG k-ε模型，采用SIMPLE算法对6个模型方案进行全流道三维数值模拟，获得各方案的扬程与效率，发现导叶出口边位置沿轴向延伸30 mm时，为最佳改进方案，此时模型泵水力效率提升1.2%，扬程增加6.8 m。同时根据各方案在设计工况下外特性的计算结果，提取各方案第1～5级的叶轮数据，发现原方案与最佳改进方案相比，首级叶轮水力效率、扬程基本相同，原方案的其余次级叶轮效率、扬程与其首级相比差距较大，最佳方案的其余次级叶轮效率与首级叶轮基本持平，扬程下降1 m，但是相比于原方案的其余各级扬程，均大约提升了2.2 m。最后分析了各方案在导叶出口截面上的内流场，结果表明：导叶出口边位置沿轴向延伸可改变液流在导叶出口处的流态，使其呈分散旋转流动，分散旋涡的数量与导叶叶片数相同；当导叶出口边延伸至适当位置时，能够减小下级叶轮的入口环量及冲击损失，改善导叶与下级叶轮之间的匹配关系。

Influence of outlet edge position of guide vane on performance of well submersible pump

Abstract: The well submersible pumps have a large number of stages and complex structures. The inflow conditions of the secondary impeller are quite different from its first stage. Provided that the inflow conditions of the remaining secondary impeller inlets cannot be guaranteed, the efficiency will be significantly reduced as compared with the first stage impeller, which will result in a decrease of the overall efficiency of entire pump and uncontrollability of the pump design. Therefore, in order to study how the space guide vane ensures the inflow conditions of the secondary impeller, especially the influence of the outlet position of the space guide vane on the inflow conditions of secondary impeller, the 250QJ125 five-stage well submersible pump was studied as a model in this paper. Under the given conditions that other geometric parameters were fixed, the position of the outlet edge of the original guide vanes was changed along axial direction to make it both perfectly perpendicular to the rotation axis and coincide with the radius line, and 6 schemes were designed, including 1 original scheme and 5 improved schemes. Based on Reynolds time-averaged Navier-Stokes equations and RNG(re-normalization group) k-ε model, the SIMPLE algorithm was used to perform the three-dimensional numerical simulation of the entire flow path. The head and efficiency of the schemes were obtained. It was found that the scheme in which guide vane outlet position extended 30 mm along the axial direction had an increase of hydraulic efficiency of 1.2% compared with the original scheme, and the head increased by 6.8 m, and it was the best scheme. At the same time, according to the calculation results of the external characteristics under the design conditions of each scheme, the impeller data from the first to fifth stage of each scheme were extracted, and it was found that the hydraulic efficiency and head of the first stage impeller were basically the same with the best improved scheme. The remaining secondary impeller efficiency and head were quite different from those of the first stage. The remaining secondary impeller efficiency of the best improved scheme was basically the same as that of the first stage impeller, and the head reduced by 1 m; however, its head was approximately increased by 2.2 m compared with the heads of the other stages of the original scheme. Finally, the internal flow field of each scheme on the outlet section of the vanes was analyzed. The results showed that the vanes' outlet edge position along the axial direction can change the flow state of the water flow at the vanes' outlet, and make it a dispersed rotating flow. The number of dispersed vortices is as same as the number of blades of the guide vane. When the outlet edge of the guide vane extends to an appropriate position, the inlet ring volume and impact loss of the following stage impeller can be reduced. The matching relationship between the guide vanes and the following stage impeller can be improved.