离心叶轮内部流动的数值模拟研究

为研究半开式叶轮叶顶间隙对其外特性及内部流场的影响,采用六面体结构化网格对模型进行网格划分,采用标准k-ε湍流模型和雷诺时均N-S方程对叶轮内部流动进行数值模拟。通过分析外特性曲线发现,叶顶间隙在一定范围变化时,间隙值的变化只影响叶轮的升压能力,对效率的影响不明显。通过对内流场的分析发现,由于叶顶间隙的存在,导致半开式叶轮内部从叶轮入口至叶轮出口存在泵前回流,回流与主流相互干扰,在叶轮入口处形成漩涡。随着叶顶间隙值的增大,回流对主流的干扰更加明显,导致叶轮内部流动恶化。

Numerical Value Simulation Study of Centrifugal Wheel Internal Flow

For studying effect of tip clearance of half-open impeller on the external characteristics and internal flow field,hexahedron structured grid is used in this text to generate mesh of model,and numerical value simulation of flow inside impeller is conducted by using standard k-ε turbulence model and N-S equation under Reynolds.By analyzing external characteristic curve we found that change of tip clearance only affects boosting pressure capacity of impeller and has little influence on efficiency.By analyzing inter flow field we found that tip clearance results in backflow in front of pump from impeller inlet to its exit inside half-open impeller.Backflow and main flow interfere with each other,causing impeller internal flow deteriorated.