离心泵关死点内部流动数值模拟

Numerical Simulation for Centrifugal Pump at Shut-off Condition

摘要:

采用非定常雷诺时均方法结合SST湍流模型,对一比转数为86.44的离心泵零流量工况下的内部流动进行了三维全流场数值模拟。基于数值模拟结果，预测了离心泵关死点扬程并与试验结果进行了比较，同时分析了关死点内部流动规律。研究结果表明，CFD预测的关死点平均扬程误差为4.7%；流道1的进口和出口各有一个旋转方向相反的漩涡，2个漩涡在一个周期内会各自发生不同的状态改变，且呈现明显的周期变化；蜗壳扩散段的绝对速度接近于零，流道1内叶片工作面的高速区面积先增加后减小；蜗壳内的静压分布变化明显，流道1的工作面出口处高压区面积随着叶轮的旋转不断减小；泵进口始终存在着6个大小不同的漩涡，且这6个漩涡基本堵塞了整个流道。

Abstract:

The unsteady full flow fields at shut off condition in a centrifugal pump with specific-speed of 86.44 were simulated by unsteady Reynolds averaged Navier-Stokes approach and SST model. The head of the pump at SOC was predicted based on CFD results. Through the comparison and analyses, it was concluded that the average head prediction errors was 4.7% compared with test result. There were two eddies in impeller flow passage No.1 and the rotation direction was opposite. The velocity at volute diffusion part was very small. The high speed area of the pressure surface in impeller flow passage No.1 increased first and then decreased. The pressure distribution in the volute changes evidently, and the high pressure area of the pressure surface in impeller flow passage No.1 at the exit area constantly decrease as the impeller rotates. There are always six different sizes of vortexes at the impeller inlet and the vortexes nearly block the whole impeller passage.