Numerical Investigation and Multi-Objective Optimization of Oil Collection Performance of an Axial Planetary Oil Scoop

The oil collection performance of a planetary oil scoop is important for the lubrication of planetary bearings. This study investigates the effects of operating and structural parameters on oil collection performance and performs multi-objective optimization. A three-dimensional oil–air two-phase flow model was established using the VOF method. The effects of oil inlet flow rate, rotational speed, oil dam height, oil feed hole diameter, oil injection distance, and number of oil feed holes were investigated. An experimental test rig was developed to validate the numerical model. A Kriging surrogate model, Sobol sensitivity analysis, and NSGA-II were then used for multi-objective optimization. The results show that increasing rotational speed, oil dam height, and oil feed hole diameter improve oil collection efficiency, while increasing oil inlet flow rate reduces it. A critical change occurs at an oil injection distance of approximately 25 mm. The maximum deviation between experimental and numerical results is 13.84%. Sensitivity analysis identifies oil feed hole diameter as the main influencing factor. The optimization results show a trade-off between oil collection efficiency and collected oil flow rate, providing a reference for planetary oil scoop design.