共用支承-转子系统耦合振动分析及试验

Coupling vibration characteristics analysis and experiment of shared support-rotors system

针对带有涡轮级间共用承力框架的高功质比涡轴发动机结构系统,建立共用支承-转子系统动力学方程,探究燃气发生器转子、动力涡轮转子与共用承力框架结构系统耦合振动产生条件及振动特性。基于ANSYS有限元仿真计算了共用支承-转子系统耦合振动特性。针对涡轴发动机涡轮级间承力框架,设计了共用支承-转子系统模拟试验器,运用激振器模拟转子不平衡激励,利用试验对模拟转子动力特性的相互影响进行了定量分析。理论计算结果表明,转子支点与支承结构通过力平衡和位移协调联系在一起,之间存在刚度耦合项,进而使共用支承-转子系统发生耦合振动。对系统振动响应仿真计算结果表明,共用支承会影响转子动力特性,不同转子不平衡激励均可激起相应转子的振动。通过试验验证了在发生耦合振动时,转子的振动响应频谱中同时包含两个转子转速频率,定义耦合影响系数,地面慢车状态两个转子相互之间的耦合影响系数分别为3.3%和60.79%,最大连续状态分别为12.78%和6.88%,最大起飞状态分别为13.56%和5.81%,转子间的动力特性耦合影响大小与频率有关系。

In view of the structural system of high power to weight ratio turboshaft engine with shared load bearing frame between turbine stages, the dynamic equation of the shared support-rotor system was established to explore the coupling vibration conditions and vibration characteristics of the gas generator rotor, the dynamic turbine rotor and the Shared load bearing frame structure system. Based on the ANSYS finite element simulation platform, the coupling vibration characteristics of the common bearing-rotor system were simulated by transient dynamics analysis method. For the inter-turbine load bearing frame of turbosshaft engine, a simulation tester of shared supplate-rotor system was designed, and a vibrator was used to simulate the unbalanced excitation of the rotor. The theoretical calculation results showed that the rotor fulcrum and the supporting structure were connected by force balance and displacement coordination, and there was a coupling stiffness between them, which led to the coupling vibration of the shared bearing-rotor system. The simulation results of the vibration response of the system under unbalanced excitation showed that the shared support could affect the dynamic characteristics of the rotor, and the vibration of the corresponding rotor could be excited by different unbalanced excitation of the rotor. It was verified through experiments that when coupled vibration occurred, the vibration response spectrum of the rotor contained two rotor speed frequencies at the same time, and the coupling influence coefficient was defined. The coupling influence coefficients between the two rotors in the idle state on the ground were 3.3% and 60.79%, respectively. The maximum continuous state were 12.78% and 6.88%, and the maximum take-off state were 13.56% and 5.81%, respectively. The coupling influence of the dynamic characteristics between the rotors was related to the frequency.