Nonlinear Dynamics of Aero-Turbine Engine Rotor–Face Gear–Planetary Gear System Under Thermal Fluid–Solid Multifield Coupling

The aero-turbine engine rotor–face gear–planetary gear system is a high-speed, complex power system, and its stability directly affects the performance and reliability of the aircraft. This paper investigates temperature’s impact on lubricating oil viscosity, backlash, and their effects on stiffness and damping. A dynamic model is developed for a planetary gear rotor face system in aviation turbines, considering multiple fields and nonlinear factors like oil film properties, meshing characteristics, backlash, transmission error, and rotor speed. Various nonlinear methods, including bifurcation graphs, maximum Lyapunov exponent graphs, and phase graphs, were utilized to analyze the impact of lubricating oil viscosity, temperature, turbine rotor speed, and time-varying mesh stiffness coefficient on the system’s nonlinear dynamic characteristics. Additionally, the stability of the system was investigated. The findings indicate that a notable bifurcation occurs in the gear system under the influence of thermal fluid–solid coupling when the turbine rotor speed surpasses 34[Formula: see text]000[Formula: see text]r/min. When the time-varying mesh stiffness coefficient of the gear system under thermal fluid–solid multifield coupling is between 0.37 and 0.6, fluid lubrication will suppress the chaotic motion of the system. Changes in the temperature field induce transitions in the gear system dynamics from chaotic to periodic motion due to the influence of lubricating oil. However, excessive temperature elevation can lead to lubricating oil failure. Conversely, when the temperature field remains constant, the coupled fluid has no impact on the stability of the gear system.