Investigation on transient dynamics of rotor system in air turbine starter based on magnetic reduction gear

As an auxiliary mechanical device, Air Turbine Starter (ATS) uses compressed air as power source to start and drive the engine. It withstands the impact of high-pressure airflow during operation, which may cause collision between key components. For this reason, it is necessary to investigate the transient dynamics of ATS rotor system. However, different from the traditional dual rotor structure, ATS uses magnetic reduction gear (MRG) as a reduction unit, which involves multiple physical fields such as magnetic field and stress field, bringing challenges to transient dynamics analysis. In this paper, the magnetic interaction forces between various rotors are innovatively simplified into the form of springs, and added to the solution model to achieve the decoupling of multiple physical fields. On this basis, the transient displacement response of MRG-ATS has been analyzed using transient dynamics theory. The results indicate that the transient displacement of the rotor system has obvious characteristics of oscillation attenuation. The study reveals the feasibility of MRG-ATS application under transient shock.