Dynamic characteristics analysis of an aeroengine rotor system subjected to aerodynamic excitation

This paper aims to investigate the dynamic characteristics of an aeroengine rotor subjected to aerodynamic excitation. Firstly, the dynamic model of the turbo-shaft engine rotor system is established by means of finite element (FE) method, taking into account the blade-tip clearance-induced aerodynamic force and oil-film force induced by squeeze film damper. Next, the critical speeds and mode shapes of the rotor are achieved by calculation, simulation and experiment to illustrate the validity of the established model. Then, using bifurcation diagram, rotating orbit and time-domain waveform, the dynamic responses of the turbo-shaft engine high-pressure (HP) rotor with aerodynamic excitation are analyzed, and the effects of blade-tip clearance, inlet and outlet angles on the dynamic responses of the rotor are discussed, respectively. The numerical results reveal that the system maintains a stable-periodic motion at low-speed region. In contrast, at high-speed region, there is a noticeable appearance of instability. Besides, the magnitude of the response decreases with the growth of the blade-tip clearance. The growth of the inlet angle will result in an increase of the magnitude of the response, and the magnitude of the response reduces with the growth of the outlet angle. The aerodynamic force at resonance is greater than that at non-resonance. The research results can assist in understanding the dynamic characteristics of the rotor subjected to aerodynamic excitation, and provide theoretical guidance for the structural design of an aeroengine rotor system.