轴流泵顶隙涡的数值模拟研究

Numerical investigation of tip leakage vortex in axial-flow pump

轴流泵广泛应用于水利工程、喷水推进以及化工过程中。为了保证泵叶与外壁不发生摩擦,在叶片顶部与外壁间都留有一定的间隙,间隙虽然很小,但其附近流动却很复杂,在很多情况下甚至会发生顶隙空化现象。该文采用数值方法,对轴流泵泵内流动特别是顶隙附近流动进行了研究。在OpenFOAM数值平台下,分别采用MRF方法和滑移网格方法,对某型轴流泵泵内流动进行了数值模拟,分析了顶隙附近的涡流结构。结果表明,在顶隙附近存在复杂的涡系,不同涡流之间和涡流与壁面之间均存在明显的相互作用。通过对这两种方法的比较,检验了数值方法的可靠性,并为进一步的顶隙空化研究作出了贡献。

Axial-flow pumps are widely used in hydraulic engineering,water-jet propulsion and chemical processes.There is a certain gap between the impeller tip and pump case to avoid interference each other.Although the gap is small,the flow around it is complicated and the cavitation occurs.In this paper,numerical methods areused to investigate the flow phenomena in an axial-flow pump,especially the region near tip clearance.The MRF method and the sliding mesh method are adopted to simulate the flow in the axial-flow pump with the OpenFOAM numerical solvers.The vortex structure near the tip clearance is analyzed.The results show that there are complex vortex structures and obvious interactions between different vortices and between the vortices with the wall.Through the comparison of two methods,the reliability of the numerical methods is validated, and it will contribute to the following research of the tip leakage vortex cavitation.