低比转速离心泵圆盘损失的计算

Calculation of disc loss in centrifugal pump with low specific speed

准确计算圆盘损失的大小是预测低比转速离心泵性能的重要因素.在泵试验结果的基础上,借助流体动力计算的数值计算和模拟方法,采用RNGk-ε湍流模型封闭时均N-S方程组,以低比转速离心泵M23-12.5为对象,在假定圆盘摩擦损失只增加轴功率而不影响液体有效能量增加的基础上,通过泵的数值预测结果和实验性能曲线的对比,对3种圆盘摩擦损失的计算方法进行比较.结果表明与直接计算叶轮外圆直径的摩擦力矩作为整个泵的圆盘摩擦损失的方法相比,根据泵叶轮的形状,分别计算其前后盖板的摩擦力矩进而求得叶轮圆盘损失的方法,更适合低比转速离心泵叶轮圆盘损失功率的计算.

Accurate calculation of the disc loss is one of the important factors for predicting centrifugal pump performance. Taking the advantage of numeric computation and simulation method for fluid-dynam- ic computation, three methods for evaluating discfrictional loss were compared with each other. In doing so, the pump experiment results were taken as a basis, the time-averaged Navier-Stokes equations with RNG k-e turbulence mode for closing Navier-Stokes equations were employed, the low specific speed cen- trifugal pump M23-12. 5 was taken as investigation object, an assumption was made that the disc friction loss would only increase the shaft power without influence on the effective energy increase, and the pump performances of both numeric prediction and experiment were compared. The result showed that it is more appropriate to compute the disc loss at the front and rear shrouds according to the shape of the pump im- peller than directly taking friction torque of impeller at its periphery as disc friction loss.