低比转数离心泵叶轮出口紊流流动结构分析

Numerical-analysis of 3D Turbulent Flow in a Low Specific Speed Pump Impeller

在叶轮内三维紊流流动数值计算的基础上 ,从介质能量的观点 ,分析了不同工况下低比转数离心泵叶轮出口处的紊流流动结构。数值计算采用 SIMPL EC算法 ,在贴体坐标系下求解 Navier- Stokes方程 ,紊流模型采用标准的 kε模型。计算结果表明 ,在叶轮的出口附近靠近吸力面一侧存在一个低能区 ,而压力面一侧能量相对较高。这与有关文献中所指出的离心风机的“射流尾流”结构相对应。当偏离设计工况时 ,该低能区的范围和强度略有增加 ,相对应的叶轮效率也降低。计算结果与水泵在这些工况下的效率实验结果相一致 。

Based on the Navier Stokes equations and the standard kε turbulence model, a 3D turbulent flow in a low specific speed centrifugal pump impeller has been simulated numerically by using the SIMPLEC algorithm in body fitted coordinates with the staggered grid system. The results indicate that there is a low energy region in the suction side near the outlet of the impeller. It corresponds to the “jet wake” structure of centrifugal compressor. With the decrease of the flow rate, the low energy region increase and the impeller efficiency also decline, which coincides with the pump efficiency measurement and shows that this low energy region is an important factor to affect the low specific speed centrifugal pump efficiency.