Analysis of the Oil Film on the Inside Surface of an Aero-Engine Bearing Chamber Housing

Abstract

Knowledge of flow and heat transfer in bearing chambers is important in the design of engine oil systems. In this paper a simplified model of the oil film on the housing of a bearing chamber is presented and the results compared with other workers’ measurements. An integral approach is used and the analysis includes the effects of surface friction, heat transfer, gravity and swirl of the oil at inlet. Two-dimensionality is assumed with variations in the axial direction being neglected. The model is expected to apply at high rotational speeds where “rimming” dominates with the oil flowing around the drum in a continuous film. A similar rimming flow regime occurs in a rotating, horizontal drum partially filled with liquid and the present model is also tested against data for this problem. Some good qualitative and quantitative agreement with measurements has been found, but significant discrepancies and uncertainties remain. Overall the results of this first attempt to analyse the bearing chamber flow are considered very encouraging.