Prediction of air/oil exit flows in a commercial aero-engine bearing chamber

Abstract

An understanding and optimization of three-dimensional air/oil flows in aero-engine transmission systems forms an integral part of future designs. This especially applies to bearing chambers, which contain a complex two-phase flow formed by the interaction of sealing airflows and lubrication oil. A critical design quantity is the composition of the liquid (oil) and gas (air) phases in the exit flows. Using a previously validated numerical model, the air/oil flow in a commercial bearing chamber is computed with particular focus on the flow exiting the chamber. The division of oil exiting the chamber through the vent and scavenge ports is determined for three shaft speeds and two configurations of the vent port. Comparison with available experimental data shows that consistent trends are predicted, but further model development is necessary in the vicinity of the scavenge port.