A Two-Phase Flow Approach for the Outlet of Lubricated Line Contacts

Abstract

In the classical Reynolds equation-based modeling of lubrication, the exit area is only considered through a pressure boundary condition which fails to predict the remaining amount of lubricant on each moving surface after the film rupture. A two-phase flow model using the Navier-Stokes equations and a diffuse interface approach is developed to analyze the lubricant behavior at the exit of rolling and sliding lubricated line contacts. After physical and numerical descriptions of the two-phase flow model, results are compared with experimental data from the literature. Good agreements are found concerning pressure profiles and meniscus exit abscissas. The model is then used to study in detail the flow behavior at the exit for different surface tensions. It is shown that when surface tension effects are important, recirculation areas occur downstream the air/oil meniscus. Sliding effects on fluid distribution are then investigated. Finally, an analytical approach is proposed, as a synthesis of the numerical results.