轴流泵马鞍区流场流固耦合数值模拟

Numerical simulation of flow field for axial pump saddle zone based on fluid-structure interaction

为了分析轴流泵不稳定运行马鞍区工况内叶轮的结构,并研究该结构的稳定性,采用雷诺时均离散方法和标准k-ε湍流模型对泵装置流场进行CFD数值模拟,利用ANSYS的Workbench平台,通过单向流固耦合模型对叶轮的应力和应变进行计算,得到了不同工况下叶轮受流体压力作用所产生的等效应力及变形量,研究了叶轮结构的应力和变形量随流量的变化特征.研究结果表明：在40%～75%设计流量下不稳定运行马鞍区,数值模拟能准确地计算轴流泵内部流场,泵装置内部流态随流量的减小逐渐紊乱.轴流泵叶片表面应力分布不均,集中分布在叶片根部,随着流量的减小最大应力逐渐增大,马鞍区工况叶片结构应力有较大的安全余量,满足强度要求;叶片进水边外缘叶尖处变形较大,振动现象明显,最大总变形量随着流量的减小先增大后减小,但大变形区域由叶尖向叶缘扩散.研究结果为轴流泵马鞍区安全稳定性研究提供了一定参考.

In order to analyze the structural problems of an axial pump impeller at unstable operation saddle zone and to study the stability of the structure,numerical simulation was applied to solve the Reynolds- averaged Navier- Stokes equation by the finite volume method,and standard k- e turbulence model was chosen in computation fluid dynamics software Fluent.The flow field and pump casing were calculated by one way fluid- solid coupling method in ANS YS Workbench,and stress distribution and total deformation distribution of the pump casing at different operating conditions were obtained and studied.The results show that an unsteady operation zone exits between 40%and 75%rated flow rate.The numerical simulation could accurately depict the flow field of the axial pump,and the unstable flow pattern of the pump device is gradually aggravating with the decreasing of flow rate.The stress of blade is markedly uneven and stress concentration occurs at the blade root,and with decreasing of flow rate,the maximum equivalent stress increases gradually,while the impeller structure satisfies the safety requirements.The maximum deformation occurs at the tip of blade inlet,and with the decrease of flow rate it increases and then decreases,while large deformation zone continues to expand.The research could provide reference for the safety and stable operation of axial flow pumps.