Simulation Analysis and Structural Improvements of Oil Return in Main Bearing Chamber of Aero-Engine

Modern advanced aero-engine bearing systems typically exhibit structural and loading characteristics with high DN values. The harsh thermal environment and multi-physics loads under operating conditions render the reliability of bearing structural systems particularly sensitive to lubrication efficiency and bearing chamber temperature. This study performs simulation analyses of oil return processes and their influencing factors in an aero-engine main bearing chamber with complex structural features. The results show two primary causes of reduced scavenging performance. On the one hand, the local low-speed region at the inlet of the scavenge pipe causes some oil to fail to enter the scavenge pipe normally. On the other hand, the air in the bearing chamber is disturbed by the rotation of the rotor, which makes oil enter the oil sump with a tendency to return to the oil collection annulus, thereby causing poor oil return. Furthermore, two structural improvements of the oil sump are proposed. These improvements avoid the disruptive effects of circumferential fluid motion in the oil collection annulus on the pressure and velocity distribution within the bearing chamber, thereby improving scavenging performance.