Investigation of Oil Scavenging Characteristics and Structural Optimization of Bearing Chambers in Aero-Engines

Abstract Driven by the goal of carbon neutrality, efficient oil circulation in aero-engine lubrication systems is essential for reducing carbon emissions and promoting green aviation. This study investigates the oil scavenging characteristics of an innovative ramp-type bearing chamber, systematically analyzes the effects of operating parameters on performance metrics, and compares it with a conventional design to reveal its advantages. Furthermore, a multi-objective optimization and decision-making process is conducted for the ramp bearing chamber by integrating the nondominated sorting genetic algorithm II (NSGA-II) algorithm with the entropy weight method, aiming to further enhance oil scavenging performance. The results show that the ramp chamber outperforms the conventional design in oil scavenging performance within investigated ranges. Scavenging efficiency and oil residence mass decrease with increasing shaft speed and oil supply temperature but increase with higher oil flow rate. Increasing the sump depth enhances both efficiency and oil retention, while enlarging the sump width initially raises efficiency before it declines; however, oil retention continues to increase. Larger vent diameters further degrade performance. Multi-objective optimization enhances the scavenging efficiency of the ramp-type bearing chamber by 6.79% and reduces oil residence mass by 6.04%. The optimization framework developed in this study demonstrates significant potential for engineering applications.