本文采用流固耦合的方法求解叶轮机械中分离流产生的叶片失速颤振。该方法固体区域采用两维弯扭模型(PAPA模型),流体区域采用半经验非线性空气动力学模型,采用四阶龙格一库塔法求解。改变流速、解耦频率比以及质量比,得到相应的叶片响应。通过计算和分析发现,当来流速度改变时,叶片扭转角的振幅出现不规则的振荡。当来流速度较大时,叶片响应出现周期解和混沌解,失速颤振发生,叶片振动逐渐变得不规则,这说明叶片振动方式随着来流速度的变化也发生了改变。
A mathematical model based on fluid-structure coupling method to study the stall flutter induced by separated flow in turbomaehinery is proposed. In this method, a typical section airfoil (PAPA model) is used for the structure region and a semi-empirical dynamic stall model for the fluid domain. The forth order Runge-Kutta method is employed to solve this model. The corresponding airfoil response is calculated respectively at different airspeed of uniform flow, uncoupled frequency and mass ratio. The results indicate that, the amplitude of torsion displacement in the airfoil system exhibits irregular oscillation under different airspeed, and the dynamics of the system undergoes great variations. When the airspeed of the uniform flow is periodic solution and chaotic solution and the blade relatively large, the stall flutter of the airfoil has vibration gradually becomes irregular.