叶片丢失对齿轮涡扇发动机风扇轴振动影响的研究

摘要

针对齿轮涡扇发动机(Geared Turbofan Engine,GTF)的动力学设计要求,考虑叶片丢失后引起的突加不平衡激励、齿轮时变啮合刚度和啮合误差对系统振动特性的影响,采用考虑剪切变形Euler-Bernoulli梁单元建立风扇-齿轮-轴-轴承机匣耦合关系的系统动力学模型.在单个叶片完全丢失的风车状态下,对比含有齿轮系统的齿轮涡扇发动机风扇轴的振动特性和不含齿轮系统的发动机风扇轴的振动特性区别.研究在不同转速下齿轮系统对齿轮涡扇发动机风扇轴振动的影响.研究结果表明:含有齿轮系统的齿轮涡扇发动机风扇轴的轴心轨迹呈现多频涡动,且轨迹都在一个稳定的极限环内;在风车状态下,啮合频率与模态频率有多个交点,系统的临界转速分布更为密集.研究结果为齿轮涡扇发动机的参数设计和后续改进提供参考.%Based on the requirement of the dynamic design of the geared turbofan engine (GTF),the effects of the sudden im balance caused by blade off,the gear time varying meshing stiffness and meshing error on vibration characteristics of the system should be investigated.In this paper,a gear-shaft-bearing-casing coupling dynamic model is established on the basis of the Euler-Bernoulli beam element considering the effect of the shear deformation.Under the windmilling condition with a single blade completely lost,the vibration characteristics of the fan shaft of the turbofan engine with and without the gear system are compared.The influence of the gear system on the vibration of the fan shaft of the geared turbofan engine under different rotaring speeds is studied.The results show that the orbit of the fan shaft center in the turbofan engine with the gearbox system exhibits a multi frequency whirling motion and has a stable limit cycle.Under the windmilling condition,the meshing frequency and the modal frequency have multiple intersections and the critical speed is denser.The results of this study could provide a reference for the parameter design and optimization of GTF engines.