直管式出水立式泵装置出水弯管优化研究

Research on the Optimization of the Outlet Elbow of the Straight Pipe Vertical Pump Device

为研究有效降低直管式出水立式轴流泵装置整体高度,对出水弯管进行优化设计,以某立式轴流泵装置模型为研究对象,以出水弯管转弯半径与直径的比值为特征参数设计多种方案,对各方案数值模拟计算,比选出最优方案,并通过模型试验验证数值模拟结果的可靠性。数值模拟结果表明:当转弯半径与直径的比值由0.8增大至1.4,泵装置效率升高约3%,弯管局部水头损失系数降低约0.3,出水流道压力恢复系数由95.77%升高至96.54%,装置性能变好;如果出水流道高程受限制,建议转弯半径与直径的比值不超过1.3;导叶、弯管、出水流道的水力损失相互影响,故若要进一步提高泵装置效率,出水流道的优化应该带泵进行整体优化,甚至可以考虑导叶与出水流道一起优化;同时设计工况下采用一维理论的弯管局部水头损失系数能比较准确地预测弯管的水力损失。

In order to effectively reduce the overall height of the straight pipe type vertical axial flow pump device,the outlet elbow is opti⁃mized.By taking a vertical axial flow pump device model as the research object,this paper designs a variety of schemes with the ratio of the turning radius and diameter of the outlet elbow as the characteristic parameter.The numerical simulation calculation of each scheme is car⁃ried out,and the optimal scheme is selected.The reliability of the numerical simulation results is verified by the model test.The numerical simulation results show that when the ratio of turning radius to diameter increases from 0.8 to 1.4,the efficiency of the pump device increases by about 3%,the local head loss coefficient of the elbow decreases by about 0.3,and the pressure recovery coefficient of the outlet channel increases from 95.77%to 96.54%.If the outlet channel elevation is limited,it is recommended that the ratio of turning radius to diameter does not exceed 1.3.The hydraulic losses of guide vanes,elbows and outlet conduits interact with each other.Therefore,to further improve the efficiency of the pump device,the optimization of the outlet conduit should be optimized with the pump as a whole,and even the guide vanes and outlet conduits can be optimized together. At the same time, the local head loss coefficient of the elbow using one-dimensional the⁃ory under design conditions can accurately predict the hydraulic loss of the elbow.