航空发动机双转子系统动力学特性分析

Analysis of Dynamic Characterization of Dual-Rotor System in Aero-Engine

摘要: 本文针对五点支承的复杂双转子系统，考虑了中介轴承的非线性，通过有限单元法建立了带中介轴承的双转子系统动力学模型。采用Timoshenko梁单元模拟轴段，刚性圆盘模拟转盘，分别得到刚度矩阵、陀螺矩阵和质量矩阵，并将各单元矩阵组合得到系统总体矩阵和系统动力学微分方程。采用Newmark-β法求解系统动力学响应，分析各转盘动力学特性。研究了转速比和不平衡量对系统动力学响应的影响。研究结果表明，双转子系统出现两个共振区；改变转速比影响高压转子基频和对应幅值，导致盘1出现拍振现象；改变不平衡量会引起各盘主频率成分的幅值增加，尤其在共振区内。

Abstract: In this paper, for the complex dual rotor system with five-point support, the nonlinearity of the inter-shaft bearing is taken into account, and the dynamics model of the dual rotor system with intermediate bearing is established by the finite unit method. The Timoshenko beam unit is used to simulate the shaft segment and the rigid disk is used to simulate the rotor, and the stiffness matrix, gyro matrix and mass matrix are obtained respectively, and the overall matrix of the system and the differential equations of the system dynamics are obtained by combining the matrices of each unit. The Newmark-β method is used to solve the system dynamic response and analyze the dynamic characteristics of each turntable. The effects of the speed ratio and the amount of unevenness on the system dynamic response are investigated. The results show that two resonance zones appear in the dual rotor system; changing the rotational speed ratio affects the fundamental frequency of the high-pressure rotor and the corresponding amplitude, which leads to the beat vibration phenomenon of disk 1; changing the amount of unevenness causes an increase in the amplitude of the main frequency components of each disk, especially in the resonance zone.