Assessment of an Enhanced Thin Film Model to Capture Wetting and Drying Behavior in an Aero-Engine Bearing Chamber

Abstract

Abstract In the present work, a wetting and drying model is coupled with Eulerian Thin-Film model (ETFM) to analyze the wetting and drying behavior inside the bearing chamber. In the enhanced model, an additional source term is included to account for the contact angle effect. These models were coupled with volume-of-fluid (VOF) such that the core region is resolved by VOF and region close to the chamber walls, where a thin film is expected is resolved by either ETFM or enhanced ETFM model. Numerical studies are conducted for a shaft speed of 5,000 rpm, lubricant and air flow rates of 100 1/hr and 10 g/s respectively, at a scavenging ratio of 4. In the case of enhanced ETFM model lubricant to surface contact angle was varied from 10° to 45°. The performance of enhanced ETFM model is evaluated to capture drying and wetting behavior on a flat plate and found to be satisfactory. Film thickness prediction of enhanced ETFM model is found to be comparable with the VOF predictions reported in the literature. The effect of contact angle on the spreading of oil and film thickness is found to be small for the investigated conditions on an aero-engine bearing chamber.