轴流泵叶轮内部流场大涡模拟及分析

本文将大涡模拟与基于特征线的有限元分离算法相结合,对轴流泵叶轮内部流场进行了数值分析.为验证算法的准确性和可靠性,对NACA0012翼型在雷诺数Re=800下且攻角为20°时的绕流流动进行计算,成功得到了该流动的双解,计算值与直接数值模拟结果相符.大涡模拟计算得到的轴流泵外特性曲线与y试验数据基本吻合,特别在偏离工况下能较好地反映泵的能量特性,表明大涡模拟有较好的工程应用前景.分析了叶轮的进出口流场速度分布及叶片表面的压力脉动,发现小流量工况时叶轮轮缘附近存在叶道涡和较强的压力脉动,此现象与导水锥段收缩流道造成的叶轮进口轴向速度非均匀分布有关.

Large-eddy Simulation and Analysis of Turbulent Flow in Axial Pump Impeller

Large-eddy simulation combined with Characteristic-Based Split Scheme is performed to investigate the turbulent flows in axial pump impeller. The method's accuracy and reliability are examined through computing the flow around a wing of NACA0012 section and comparing results with DNS data. The predicted external characteristic curves of axial pump are basically identical with experiment data. Blade channel vortex and hydraulic pressure fluctuation are captured at blade tip under low flow rate condition. The unfavorable phenomena are related to the non-uniform distribution of impeller inlet axial velocity.