Alford力作用下计及叶片振动的转子-轴承系统动力学特性分析

为了分析非线性耦合因素与叶片振动对转子-轴承系统动力学特性影响,文章将叶片模化为悬臂梁结构并利用假设模态法离散简化,建立了阿尔福德(Alford)力作用下计及叶片弯曲振动的系统动力学模型。采用Runge-Kutta法对非线性振动微分方程进行数值求解,通过系统响应的分岔图、时间历程图与频谱图、轴心轨迹图、Poincaré映射图和相图研究了叶片弯曲变形以及Alford力对系统的非线性动力学行为的影响。结果表明:叶片振动使系统的不稳定区域提前,转子发生混沌运动的转速范围增大;叶尖气隙引起的Alford力使系统的运动状态变得更为复杂,油膜非线性更加明显。

Dynamic characteristic analysis for rotor-bearing system with Alford force considering blade vibration

To analyze the impact of nonlinear coupling factor and blade-bending vibration to dynamic characteristics of rotor-bearing system,the blade was modeled as a cantilever beam and simplified by the assumed modes method,a dynamic model was set up to express vibration characteristics of the system with nonlinear Alford forces considering blade-bending vibration.The nonlinear motion equation was numerically calculated by classical Runge-Kutta method.The bifurcation diagrams,portraits of central point of shaft,Poincarésection and phase spectrum map were obtained to analyze the influence of blade bending deformation and Alford force on the nonlinear dynamic characteristics of the system.The results indicated that the bladebending vibration advances the unstable region of the system and increases the chaotic motion of rotor system speed range.The Alford forces caused by blade tip clearance make the motion state of the system more complex,and the oil film nonlinearity is more obvious.