导叶出口安放角对双向轴流泵水力性能影响研究

Research on the Effect of Guide Vane Outlet Placement Angle on the Hydraulic Performance of Bi-directional Axial Flow Pumps

随着湿地生态保护治理过程中对双向轴流泵的需求日益增加,开发设计双向轴流泵已然成为重要课题,为了探究导叶出口安放角对轴流泵双向运行性能的影响,以一台比转速为903的轴流泵为研究对象,利用ANSYS CFX软件的标准k-ε湍流模型对5种不同导叶出口安放角的双向轴流泵进行定常和非定常数值模拟,研究分析了导叶出口安放角对轴流泵双向运行的外特性、水力损失、内部流场、压力脉动的影响。结果表明:正向运行设计工况下,减小导叶出口安放角,可减小导叶部分水力损失,并且减小导叶吸力面低压区面积,因脱流产生的能量损失也随之减小,轴流泵效率明显增大;设计工况反向运行时,随着导叶出口安放角的减小,导叶回收能量的能力也随之减小,导叶部分水力损失增加,并且轴流泵效率降低。改变导叶出口安放角度,可对正向运行时轴流泵内压力脉动产生一定影响。适当增加正向运行时导叶出口安放角均能在一定程度上减小轴流泵内压力脉动幅值,改善能量损失;导叶出口安放角对双向轴流泵反向运行时的压力脉动幅值大小无明显影响。因本次研究的轴流泵为双向运行,结合正反两向效率变化相反的情况,考虑该轴流泵在双向运行时均有较高效率的运行范围,所以取导叶出口安放角为80°时,双向轴流泵综合性能最优。

With the increasing demand for bidirectional axial flow pumps in the process of wetland ecological protection and management,the development and design of bidirectional axial flow pumps has become an important topic.In order to investigate the influence of guide vane outlet angle on the bi-directional operation performance of axial flow pump,this paper takes an axial flow pump with specific speed of 903 as the research object,and uses the standard turbulence model of ANSYS CFX software to conduct constant and non-constant numerical simulations of five different guide vane outlet angles of bi-directional axial flow pump,and studies and analyzes the influence of guide vane outlet angle on the external characteristics,hydraulic loss,internal flow field,pressure pulsation.The results show that under the design conditions of forward operation,reducing the angle of the guide vane outlet can reduce the hydraulic loss of the guide vane and the area of the low-pressure area of the suction surface of the guide vane,the energy loss due to decurrent flow is also reduced,and the efficiency of the axial flow pump is obviously increased.In reverse operation,with the decrease in the placement angle of the guide vane outlet,the ability of the guide vane to recover energy also decreases,the hydraulic loss of the guide vane part increases,and the efficiency of the axial flow pump decreases.Changing the placement angle of the guide vane outlet can have a certain impact on the pressure pulsation in the axial flow pump during the forward operation.Properly increasing the guide vane outlet placement angle during the forward operation can reduce the amplitude of pressure pulsation in the axial flow pump to a certain extent and improve the energy loss.The placement angle of the guide vane outlet has no significant effect on the pressure pulsation amplitude when the bidirectional axial flow pump runs in reverse.Because the axial flow pump studied in this paper operates in two directions,combined with the situation that the efficiency changes in the forward and reverse directions are opposite,considering that the axial flow pump has a high efficiency operating range in the two-way operation,so when the guide vane outlet placement angle is 80°,the comprehensive performance of the two-way axial flow pump is optimal.