摘要
应用ANSYS有限元软件对一个小型燃气轮机向心涡轮的叶轮模态进行了数值分析。建立了有限元形式叶轮的动力学方程,对方程中非线性的初应力刚度矩阵与离心刚度矩阵采用了线性化简化,应用 Block Lanzos法求解动力学方程的特征值问题,得到了该叶轮的前25阶模态。此外还基于旋转梁的动力学方程,建立叶轮的简化的动力学方程以说明叶轮基本的振动特性。这些特性在数值分析结果中得到了验证。结果表明:由于旋转柔化效应,当叶轮转速上升时,在某一个转速前,各阶频率有不同程度下降,尤其是一阶弯振频率,过了这个转速一阶弯振频率有个突然的阶越。整体式叶轮振动形式主要是叶轮的弯扭振动。
Based on the general FEA platform ANSYS, this paper presents the numerical results of the modal analysis of a radial inflow turbine impeller. The dynamical equation of impeller in the form of FEM is derived with linearized initial stress and centripetal stiffness matrices are linearized. Eigen problem of the dynamical equation is solved by means of Block-Lanczos method with the first 25 modes of the impeller obtained. In addition, the simplified dynamical equation is founded upon the dynamical equation of spinning beam, in order to explain the major dynamics characteristics of the impeller, which are validated in numerical analysis. Results indicate that because of the spin softening, as a critical rotation speed is approached, the frequencies of each modes tend to fall, the first bending mode is especially more evident. Then, the frequency of the first bending mode jumps abruptly. The shapes of major modes are bending and torsion.
出处
《内燃机工程》
EI
CAS
CSCD
北大核心
2005年第1期77-80,共4页
Chinese Internal Combustion Engine Engineering
基金
上海市重点学科能源岛项目
关键词
叶轮
强度
振动
Bending strength
Finite element method
Modal analysis
Numerical analysis
Vibrations (mechanical)
