Numerical simulation on the oil capture performance of the oil scoop in the under-race lubrication system

Abstract

The under-race lubrication system providing a moderate amount of oil to high-speed bearings is one of the key factors to ensure its good lubrication and cooling. To investigate the oil capture performance of the oil scoop, a complete numerical calculation model was established, and unsteady simulations of oil–gas two-phase flow inside the under-race lubrication system were carried out. The results indicate that the oil capture efficiency increases first and then decreases with increasing rotating speed at different oil jet velocities. The ratio of the rotating Reynolds number of the oil scoop to the Reynolds number of the oil jet corresponding to the maximum oil capture efficiency changes linearly with oil jet velocity. There are three variation trends of oil capture efficiency at different rotating speeds with the increase of oil jet velocity: monotonically decreasing, first increasing, and then decreasing and monotonically increasing. However, the amount of oil captured by the oil scoop increases monotonically under all operating conditions. The effect of oil temperature on oil capture efficiency is mainly due to the change of dynamic viscosity of the oil. The oil capture efficiency can be improved by appropriately increasing the oil temperature within a certain temperature range.