基于泵轴流固耦合的双向流道轴流泵装置的数值分析

A Numerical Analysis of Axial-flow Pumping System with Two-way Passages Based on Pump Shaft Fluid-structure Interaction

首次采用双向同步求解的方法对一台灌排双向轴流泵装置的内流场和泵轴结构响应进行联合求解,运用雷诺时均Navier-Stokes方程和SST k-ω湍流模型进行三维非定常计算,采用多重坐标系法,结构响应基于弹性体结构动力学方程。对比分析了流固耦合作用前后出水流道中静压和速度分布以及导叶出口面上的压力脉动情况和湍流动能分布,并将外特性的计算结果与试验值进行了对比。分析结果表明:与不考虑流固耦合相比,出水流道中静压相对较大的区域面积增大,而流速分布变化较小;导叶出口面上压力波动的相位发生改变,脉动强度也增大;小流量下,耦合作用使得导叶出口的湍流动能增大,而设计流量和大流量下,湍动能分布变化较小。此外,外特性的吻合性也说明了模拟计算的可靠性。总体来看,流固耦合前后其流场的分布规律虽然趋势一致,但也有一定的区别,对大型双向轴流泵装置流固耦合计算更能反映实际情况。

A combined calculation for turbulent flow and structure response of pump shaft is first established by using the two-way coupling method to study the effect of FSI （ Fluid Solid Interaction） of pump shafts on the flow field in axial-flow pumping system with two-way passages irrigation and drainage. The three-dimensional unsteady turbulent flow with Reynolds averaged Navier-Stokes equations and SST k-w turbulent model with multiple reference frames are chosen to do the simulation, and the structure response is based on elastic structural dynamic equation. The static pressure and velocity distributions in outlet passage, pressure fluctuation and TKE（ Turbulence Kinetic Energy） distributions on plane of diffuser outlet are analyzed, comparing with the results without FSI. It shows that, the area of bigger static pressure in outlet passage increases, and few changes are found on velocity distribution. The phrase of pressure fluctuation on plane of diffuser outlet changes obviously with the increase in fluctuation intensity. In addition, a good agreement of pumping system performance between simulation and experimental results shows the reliability of calculation. Overall, although there is the same distribution of flow field in the pumping system whether FSI or not, few differences still exist and FSI simulation can better show the real flow field for axial-flow pumping system with twoway passages.