贯流泵内部湍流流动及叶轮流固耦合特性

Turbulent flows in tubular pump and fluid-structure interaction characteristics of impeller

基于RNG k-ε湍流模型,应用Ansys Workbench软件,对前置竖井式贯流泵内部湍流流动和结构静应力进行数值分析.模拟显示不同工况下泵的外特性曲线和试验值总体变化趋势一致,模拟的扬程比试验值稍高,效率稍低,但误差都保持在10%内;除出水流道隔断前部外,贯流泵整个流道流态均匀;出水流道前段的螺旋线分布的流线表明,水流在经过导叶后存在未回收的速度环量;在设计工况下,压力最小值出现在吸力面靠近进口边,此处最易导致空化.进一步采用单向流固耦合方法,对叶轮在不同工况下的静应力和总变形量进行分析,结果表明:设计工况下,叶轮的最大等效应力出现在叶片压力面和轮毂相交处,叶轮变形的总位移随着半径增大而不断增大,最大变形量出现在轮缘附近.计算结果将为贯流泵的优化设计提供一定参考.

The RNG k-ε turbulence model and the Ansys Workbench software were used to numerically investigate internal flows in a front-positioned shaft tubular pump and fluid-structure interaction in its impeller.The simulated performances under different operation conditions are consistent with experimental data.Even though the calculated head is higher and the efficiency is lower than the experimental data,their errors are less than 10%.The velocity and pressure of fluid are uniformly distributed in the whole passage of the pump except in the discharge passage.The spiral streamlines in the front of the discharge passage show that the fluid has a residual velocity circulation after it leaves the vaned diffuser.At the design flow rate,a minimum pressure is seen on the suction surface of blade near the blade leading edge,where cavitation will be apt to occur.In addition,a static structural analysis on the impeller was carried out based on one-way fluid-structure coupling method and the stress and deformation of blades were predicted under different operating conditions.The results show that at the design flow rate,there is a maximal equivalent stress on the pressure surface of blade but at the junction of blade and hub.The total deformation of blade increases with radius,and there is a maximum deformation near the impeller tip.The calculated results will provide a reference for optimization design of tubular pumps.