Thermal Characteristics and Dynamic Performance Analysis of Aero-Engine Bearings Based on a Thermal–Fluid–Solid Coupling Model with Frictional Power Consumption

Modern aero-engine bearings operate under demanding rotational and thermal conditions, where inaccurate prediction of thermal behavior and an incomplete understanding of heat-transfer mechanisms may increase the risk of thermal failure. This study develops a thermal–fluid–solid coupling method to investigate heat generation and heat transfer in aero-engine bearings. The frictional power consumption analysis evaluates rolling friction, sliding friction, seal friction, and oil-churning power consumption. In the conjugate thermal–fluid calculation, only the contact-related rolling and sliding friction contributions are transferred to the raceway surfaces through the prescribed heat-flux boundary conditions. Thermo-elastohydrodynamic lubrication (TEHL) theory is introduced to describe the physical relationships among bearing contact conditions, lubricant-film behavior, and thermal effects, rather than as an independently solved full-field TEHL model. A hybrid heat-flux density distribution model combining a Gaussian distribution in the contact zone with exponential decay in the oil-film zone is proposed. The prescribed raceway thermal loads are incorporated into a three-dimensional conjugate thermal–fluid model to investigate the bearing temperature and lubricant flow responses. With prescribed reference heat-flux density amplitudes for the inner and outer raceways, the model describes their distinct spatial distributions, with stronger local concentration on the inner raceway. Numerical simulations and bearing temperature-rise tests are conducted to assess the thermal response predicted by the model. The prescribed inner- and outer-raceway thermal loads produce distinct local thermal responses, with stronger local heat-flux concentration on the inner raceway and different heat-transfer characteristics in the surrounding lubricant flow field. The numerical results show that the thermal and dynamic responses vary non-monotonically with oil supply rate, indicating a strong dependence on lubricant distribution and local heat-transfer conditions. Within the investigated conditions, the principal stiffness and damping reach their maximum values at an oil supply rate of 0.6 L/min. The proposed framework captures the main thermal response trends of the bearing and provides a theoretical basis for lubrication parameter optimization and bearing thermal management.