基于流场计算的离心泵性能预测比较

The Prediction of Characteristics of Centrifugal Pumps Based on CFD

简述了基于流场计算法预测离心泵能量性能的研究现状。为了详细研究各种基于流场计算进行离心泵性能预测方法的精度,采用RANS定常数值计算、RANS非定常数值计算和大涡模拟分别对2台不同比转速的离心泵设计工况下的内部流场进行了数值模拟。根据数值模拟结果预测了2台离心泵的外特性并将各模型扬程和效率的预测结果与试验结果做了详细比较。同时对非定常流场计算所需要的周期数进行了研究。研究结果表明,离心泵非定常数值计算至少要进行5个周期的计算才能获得稳定的预测结果;离心泵能量性能的脉动周期与叶频相同;RANS非定常数值计算与LES模拟的外特性平均预测精度基本相同,都高于RANS定常数值计算的外特性预测精度。

A simple introduction is made of the present situation about characteristics prediction of centrifugal pumps based on CFD. In order to study the prediction precision of the methods based on CFD, the flow field under design conditions in two centrifugal pumps are simulated by RANS steady method, RANS unsteady method and IrES method. The specific speeds of the two pumps are different. According to the simulation results, the energy characteristics of the three centrifugal pump models are predicted and the head and efficiency of the three models are compared with the experiment results in detail. Also, the periodic number of unsteady nu mcrical simulation for adequate prediction precision is analyzed. The research results indicate that more than five periods are required for the numerical unsteady simulation. The pressure fluctuation cycle of energy characteristics equals blade passing frequency. The average characteristics prediction precision of RANS unsteady method is basically the same as that of LES method. The prediction precision of the RANS steady method are lower than that of unsteady simulation.