Multi-objective optimization of oil scavenging and heat transfer in aero-engine bearing chambers

Efficient oil scavenging and thermal management in bearing chambers are critical for the reliable operation of aero-engine lubrication systems. Current bearing chamber designs primarily focus on enhancing oil scavenging performance, often neglecting the coupled effects of flow and heat transfer. To address these issues, this study investigates the characteristics of a novel ramp bearing chamber and develops an optimization framework for the coordinated improvement of oil scavenging and heat transfer performance. The results show that, compared to baseline designs, the ramp structure enhances oil scavenging by suppressing oil accumulation and directing oil flow toward the scavenge port. Oil scavenging efficiency decreases with increasing rotational Reynolds number but increases with higher oil-sling Reynolds number and Prandtl number, while the wall-averaged Nusselt number rises with these operating parameters. Variations in structural parameters reveal a trade-off between oil scavenging and wall heat transfer. Sensitivity analysis identifies the scavenge port diameter as the dominant parameter affecting oil scavenging efficiency, and the sump depth as the most influential parameter for the Nusselt number. The interaction between sump width and depth further reflects the influence of sump space on oil distribution and heat transfer. Following optimization, the maximum improvements among the optimized schemes are 8.7% in oil scavenging efficiency and 8.4% in the wall-averaged Nusselt number. The proposed optimization framework and decision-making strategy enable the selection of oil-scavenging-prioritized, heat-transfer-prioritized, and compromise optimization schemes according to different design preferences, thereby providing engineering support for the refined design of aero-engine lubrication systems.