基于流固耦合的轴流泵叶片应力特性

为计算轴流泵叶片的应力及变形情况,在Workbench平台上,采用Ansys和CFX软件对轴流泵内部流场和叶轮结构响应进行双向顺序流固耦合联合求解,其中流场计算基于RANS方程,采用RNG k-ε双方程湍流模型,结构计算采用弹性体结构动力学方程.对叶轮叶片在流固耦合作用下的变形和应力分布进行了计算,分析了流固耦合作用对轴流泵扬程和效率的影响.计算结果表明:在流固耦合作用下轴流泵叶片的最大位移发生在叶片进水边轮缘处,叶片出水边及根部位移较小;叶片根部与轮毂接触处靠近进水边一侧存在明显的应力集中现象;叶片的应力和变形均随轴流泵流量的增大而逐渐减小;与不考虑流固耦合作用相比,考虑流固耦合作用的数值计算得到的轴流泵扬程和效率均有所下降,但下降幅度较小.

Stress characteristics in blades of axial-flow pump based on fluid-structure interaction

In order to predict the stress and deformation of blades in an axial-flow pump,a coupled solution of flow field in the pump and structural response of the blades was established by using two-way coupling method on Ansys platform-Workbench where CFX was used to compute the flow field,and Ansys dynamic structure code was applied to analyze the stress. The flow field prediction was based on the Reynolds-averaged N- S equations and the RNG two equation k- ε turbulence model; the structure response was handled by the elastic structural dynamic equations. Not only the deformation and stress distribution characteristics caused from fluid-structure interaction were identified,but also the influence of the interaction on the head and efficiency of the pump was analyzed. The results indicated that the maximum displacement occurs on the blade leading edge at impeller tip,but a smaller displacement appears on the blade trailing edge and in the blade root. A significant stress concentration occurs in the inlet side and the contact area of the blade root and the hub. All the stress level and deformation in the blades reduce steadily with increasing flow rate. The head and efficiency predicted by fluid-structure interaction model are lowered compared with those by the rigid structure model. However,this reduction in stress and deformation is very small.