脉冲爆震载荷作用下转子系统动力学特性

针对脉冲爆震涡轮发动机(PDTE)气动载荷具有周期性、非定常的特点,应用有限元法建立了PDTE转子系统动力学特性计算模型。在验证计算模型准确性的基础上,研究了周期性、非定常轴向力和扭矩对转子系统动力学特性的影响。研究结果表明:与传统燃气涡轮发动机相比,PDTE转子系统同时存在弯曲振动、轴向振动和扭转振动。脉冲爆震燃烧室的气动载荷会改变转子系统的弯曲刚度,但对气动载荷合理设计后,其对弯曲振动的影响较小。周期性、非定常轴向力引起转子系统轴向振动,且轴向振动特性主要受零频和1阶轴向共振频率处响应的影响。PDTE工作时滚珠轴承的轴向支反力会不断变向,在设计滚珠轴承时应予以考虑。周期性、非定常扭矩引起转子系统扭转振动,1阶扭转共振频率分量在扭转振动响应中占优。 

Dynamic characteristics of rotor system subjected to pulse detonation aerodynamic loads

In view of the periodic and unsteady aerodynamic loads of pulse detonation turbine engine(PDTE), finite element method was used to establish a dynamic characteristics calculation model for rotor system of PDTE. On the basis of verifying the accuracy of the calculation model, the effects of periodic and unsteady axial force and torque on the dynamics characteristics of rotor system were studied. The results show that compared with traditional gas turbine engine, the rotor system of PDTE has bending vibration, axial vibration and torsional vibration at the same time. Aerodynamic loads of pulse detonation combustor change bending stiffness of rotor system, but it has little effect on bending vibration in case of reasonable design. Periodic and unsteady axial force causes axial vibration of rotor system, and the axial vibration characteristics are mainly affected by the responses at zero frequency and the first order axial resonance frequency. When PDTE is in service state, the axial reaction force of ball bearing changes direction continuously, which should be considered in the design of ball bearings. Periodic and unsteady torque causes torsional vibration of rotor system, and the first order torsional resonance frequency component is dominant in torsional vibration response.