Effect of lubricant properties on the thermal behavior of aeroengine mainshaft ball bearings

For high-temperature and high-speed aeroengine mainshaft ball bearings, lubricant properties directly determine service life and may even endanger flight safety, making proper selection essential. In this study, a newly developed aviation lubricant, 4102 (7 cSt), was compared with commonly used lubricants, 4010 (3 cSt) and 4050 (5 cSt). Oil film traction tests were performed under various loads, temperatures, and speeds to establish traction coefficient models. Based on bearing dynamics theory, a dynamic analysis model was developed, and a calculation method integrating heat flux density with a thermal network approach was proposed to analyze the bearing temperature field and the temperature distribution in the ball–raceway contact ellipse. Using these models, the influence of lubricant properties on the thermal performance of ball bearings was systematically investigated, and lubricant selection criteria were formulated. Experimental validation showed that the maximum relative deviation between predicted and measured bearing temperature rise was less than 10 %. The results provide a theoretical foundation for the rational selection of lubricants in aeroengine mainshaft bearings and offer important guidance for improving aeroengine performance and reliability.