不同离散格式下的离心泵内部流动数值模拟研究

为研究离散格式对离心泵性能预测精度的影响,本文以自吸式离心泵为计算模型,采用Realizableκ-ε湍流模式进行三维内流场的数值模拟研究,分析了从零流量到最大工作流量下的内部流动和水力性能。建立了考虑内部间隙影响的自吸式离心泵全三维计算模型,分析了动量方程对流项采用一阶差分和二阶差分格式对计算精度的影响,同时分析了压力项的Standard和PRESTO离散格式对计算精度的影响。结果表明,在小流量工况下,采用二阶迎风格式具有较高的计算精度,而在大流量工况下采用一阶迎风格式更为合适。该结果可为准确预测离心泵全工况外特性提供参考依据。

Numerical Simulation on a Centrifugal Pump Under Different Discrete Scheme

A self-priming pump was adopted to research the effects of discrete scheme on performance prediction accuracy of the centrifugal pump.The Realizableκ-εturbulent model was applied to simulate the three dimensional flow in a self-priming pump,and the pump performance from zero flow-rate to maximal flow-rate were analyzed.The three dimensional model considering seal clearance was set up,and then the effects of first-order differential and second-order differential scheme of convection item in the momentum equation on calculation precision were analyzed,as well as the Standard and PRESTO differential scheme of pressure item.The results show that the second-order differential scheme has higher accuracy for solving the small flow-rate condition of pump,and the first-order differential is more appropriate for large flow-rate condition.Such result provides reference for accurate performance prediction of a centrifugal pump in full operating condition.