航空发动机转子系统建模方法和振动特性分析

针对现代航空涡扇发动机转子系统的结构和力学特征,运用有限元法对其低压转子进行了有限元建模方法和动力特性研究.分别采用二维梁单元和三维实体单元建立转子系统的有限元模型,对其动力特性计算结果进行比较分析,在此基础上,提出了等效圆盘法进行有限元建模的等效原则.等效圆盘法将转子系统的叶片等效为刚性圆环,既能保留转子系统的结构和力学特征,又能有效地控制模型规模,将周期问题转化为轴对称问题,便于有限元程序的求解计算.计算结果表明,该方法是一种适用工程实际的有限元建模方法.

Modeling method and vibration characteristics of aero-engine rotor system

According to the structural and mechanical properties of rotor system on the modern turbofan engine, an investigation about the finite element modeling technology and dynamic characteristics of low-pressure rotor was proposed, based on the finite element method (FEM). The finite element model of rotor system was developed by 2D beam element and 3D solid element separately and the dynamic characteristics were analyzed. Then a principle of finite element modeling, which is called equivalent-disk method, was presented. The equivalent-disk method regards the blades of rotor system as a rigid ring and changes the periodic model into axisymmetric model, which is favorable for FEM software in solving. It can not only keep the structural and mechanical properties of rotor system, but also control the scale of FEM model. The result indicates that this kind of equivalent method can improve the modeling techniques of rotor system on the turbofan engine and it is applicable in engineering.