轴流泵叶顶泄漏涡流体动力学特性数值模拟

Numerical Simulation of Tip Leakage Vortex Hydrodynamics Characteristics in Axial Flow Pump

基于SST κ-ω湍流模型和局部优化的高质量结构化网格，对南水北凋工程天津同台测试的TJ04-ZL-02型轴流泵水力模型进行了数值计算，并探究了叶顶泄漏涡的流场结构和流体动力学特性。数值计算和试验结果表明，基于SST κ-ω湍流模型可准确地对间隙泄漏流和边界层流动进行数值模拟；叶顶泄漏涡形成的动力为叶片工作面和背面的压差，由于叶片进口边压差最大，叶顶间隙泄漏流的流速较高，随着叶片弦长系数A的逐渐增大，叶片工作面和背面之间的压差逐渐减小，间隙泄漏流的速度和泄漏涡强度均逐渐降低；IIP顶区的局部低压区主要集中在靠近压力面间隙内分离涡的旋涡区以及叶片背面下部叶顶泄漏涡区域，叶片背面局部低压区域随着叶片弦长系数A的逐渐增大，距离叶片背面的间距增大；叶片轮缘靠近叶片工作面附近的局部低压区主要是由叶顶拐角诱导的分离涡引起，而叶片下部的局部低压区主要是由叶顶泄漏涡引起，上述过程揭示了轴流泵叶顶闸隙泄漏涡的流动特性．．

The scaled model pump of TJ04 - ZL - 02 hydraulic model, which has been applied on the Tianjin same test-bed for South-to-North Water Transfer Project, was simulated base on fine calculation for tip region flow field and SST κ-ω turbulence model, and flow field structure for tip leakage vortex as well as filed dynamic characteristics were studied. Numerical calculations and experimental results show that numerical simulations for clearance leakage and boundary layer flow based on SST κ-ω turbulence model are relatively accurate. The power arose from tip leakage vortex is regard as differential pressure between the pressure side and the suction side of blade. For the pressure difference of blade leading edge is the largest, velocity of tip leakage flow is higher. The pressure difference between blade pressure and suction side is increased gradually with the increase of blade chord coefficient A, and clearance leakage flow velocity as well as leakage vortex strength is decreased gradually. The local low pressure of blade tip region mainly occurs on vortex region of separated vortex near the pressure surface, as well as tip leakage vortex region at the lower part of blade suction side. The local low pressure region of blade suction side is getting further away from blade suction side with the increase of blade chord coefficient A. The local low pressure region of blade rim near blade pressure side is mainly caused by separated vortex which is induced by blade tip corner, and the low pressure near suction side of blade is resulted from tip leakage vortex, and the process reveals the flow characteristic of tip leakage vortex for axial flow pump.