摘要
为了分析转子在油膜力和气流激振力共同作用下的非线性振动特性，本文以短轴承支撑的不平衡刚性对称Jeffcott转子系统为研究对象，首先分析转子在非稳态油膜力作用下的振动特性，然后分析转子在油膜力和气流激振力共同作用下的非线性振动特性。采用数值模拟的方法研究了系统的分岔和混沌特性，计算结果表明，考虑气流激振力和油膜力共同作用下的转子系统与仅考虑油膜力的转子系统相比，在相对进气速度v=30m／s时，随着无量纲转速ω的增加。二者都出现了周期运动和混沌运动多次交替出现的复杂运动特性，但是前者首次出现倍周期分岔和混沌运动时的转运提前，在定转速情况下，随着v的增大，系统最终在经历周期运动之后进入混沌运动，而且圆盘中心的最大振幅随着v的增大而增大。
The stability of a rigid unbalanced Jeffcott rotor supported by short journal bearings was discussed in the paper, in order to analyse its nonlinear aspects of the rotor under the oil-film force and airflow exciting-vibration force （Alford force）. The dynamic characteristics of the rotor under the unsteady oil-film force was analyzed firstly, and then were the nonlinear aspects of the system under the two kinds of nonlinear forces, The bifurcation and chaos behavior of the system varying with the rotary angular speed and the relative velocity of the airflow （v） were obtained through numerical simulations. The results of calculation show that, comparing to the case with the system under the oil-film force, the responses of the system under the two kinds of forces are very complex, periodic and chaos occurring alternately with increasing the angular speed when v=30m/s. The angular speeds corresponding to the bifurcations in the latter case are less than those in the former ease, and the chaos occurs through the periodic-doubling bifurcations with increasing v when fixing the rotary angular speed of the rotor. The amplitude of the rotor center is enhancing with increasing v.
基金
天津市自然科学基金项目（043603511,043103611）和国家自然科学基金项目（10272078）资助
关键词
转子
非线性
油膜力
气流力
分岔
混沌
turbine rotor, nonlinear, oil-film force, Alford force, bifurcation, chaos
