转子突加不平衡的碰摩响应

航空发动机等高速旋转机械在工作时会出现叶片掉块、飞失等突加不平衡情况,突加不平衡引发的碰摩可能导致转子失稳和系统的破坏.本文对一个具有非线性支承刚度的跨中转子在突加不平衡时的碰摩响应进行了数值仿真,计算发现系统在突加不平衡发生后将会出现6种不同的碰摩响应形式,给出了参数-突加不平衡转速平面上不同稳态动力学响应模式的边界曲线,同时针对系统在突加不平衡发生后减速通过临界转速时的失稳现象,给出了失稳边界,研究表明增大转子阻尼,降低转静接触刚度和摩擦系数,可以减小失稳的转速范围.分析了参数对系统瞬态响应的影响,瞬态响应随转速的变化会发生跳跃,而瞬态响应随突加不平衡偏心量的变化,在低于共振转速时是平缓增大的,而在高于共振转速时也会有跳跃发生.

Sudden imbalance rubbing response of a rotor system

Sudden imbalance, such as the disfigurement and the loss of blade for the high speed rotation machinery (e.g. aero engine) can lead to the instability and damage of the rotor. In this paper, numerical simulation is employed to study the sudden imbalance rubbing response of a rotor system. Results show that sudden imbalance leads to 6 different forms of rubbing response. The transitions of the steady-state response in the plane of parameter-rotation speed are given. The instability during the speed reduction after sudden imbalance is considered, and the stability boundaries of rotation velocity are also given. It is found that increasing the rotor damping as well as decreasing the contact stiffness and friction coefficient can reduce the unstable range of rotation velocity. Moreover, the influence of the parameters on transient responses of the system is investigated. It is shown that transient responses jump with the change of rotation speed. When the rotation speed is below the resonance speed, transient amplitude gently increases with the sudden imbalance eccentricity, but when it is above the resonance speed corresponding to a given eccentricity, the transient amplitude also jumps.