分流叶片对螺旋离心泵径向力的影响

Numerical Simulation on Radial Hydraulic Forces for Screw-type Centrifugal Pump with Splitter Blade

为了改善单叶片螺旋离心泵叶轮径向力过大的问题,对单叶片叶轮设计分流叶片,并采用Navier-Stokes方程和标准的k-ε湍流模型对带分流叶片和不带分流叶片的螺旋离心泵的内部流场进行非定常数值模拟。通过模拟分别获得了带分流叶片和不带分流叶片的螺旋离心泵的蜗壳出口压力脉动特性以及作用在蜗壳和叶轮上的径向力特性,并对其进行分析比较。结果表明:各个工况下,带分流叶片和不带分流叶片的螺旋离心泵的蜗壳出口压力脉动特性、作用在蜗壳和叶轮上的径向力均呈周期性变化,且主频均为各自叶片通过频率;采用分流叶片后周期变为原模型周期的一半,蜗壳出口压力脉动幅值明显减小,作用在叶轮上的径向力明显减小,作用在叶轮上的径向力的变化趋势关于坐标轴对称性加强,且基本呈椭圆形分布;作用在蜗壳上的径向力虽有小幅提升,但是其脉动幅值减弱,且高频脉动减少。表明单叶片螺旋离心泵叶轮分流叶片的添加不仅可以有效减小叶轮上的径向力,而且对降低蜗壳上的振动特性有一定的积极作用。

In order to solve the overlarge radial hydraulic forces on the impeller of screw-type centrifugal pump with single blade, splitter blade was added. Based on Navier - Stokes equations and k -ε turbulent model, three-dimensional unsteady flow field of the pump was simulated numericaUy to the screw-type centrifugal pump with and without splitter blade. Pressure fluctuations in the outlet of pump, radial hydraulic forces on the impeller and volute were obtained at different flow rates. The analysis results indicated that the pressure wave in the outlet of pump, radial hydraulic forces wave on the impeller and volute were always periodic in the two models, impeller blade passing frequency was the dominant frequency. Compared with the result without splitter blade at different flow rates, the period decreased to a half, the amplitudes of pressure fluctuations in the outlet of pump was smaller, the radial hydraulic forces on the impeller decreased a lot, the distribution of radial hydraulic forces on the impeller vector coordinates were more symmetry, and almost ellipses, the radial hydraulic forces on volute increased a little, but the amplitudes of which was decreased, and the high-frequency components were also fewer. The analysis results indicate that the adding of splitter blade in impeller of screw-type centrifugal pump with single blade can not only decrease the radial hydraulic forces on the impeller, but also decrease oscillations in volute as well.