Non-Newtonian EHL model for traction evaluation in a roller-inner ring contact in a roller bearing

Abstract

This work is concerned with the evaluation of the friction coefficient in an EHD roller-inner ring contact, in a roller bearing for a jet engine application, considering a non-Newtonian behaviour of the lubricant.In order to simplify the analysis, of this complex problem, the elastohydrodynamic contact is simulated by a dry Hertzian contact, whose surfaces are separated by a thin lubricant film. The film thickness is corrected by a thermal factor that takes into account the inlet viscous shear heating.The lubricant behaviour inside the EHD contact is represented by two rheological laws, respectively the viscous and the viscoelastic models, both with a Ree-Eyring fluid. All the analytical expressions for the definition of both models are presented and developed.Two piezoviscosity and thermoviscosity laws for the lubricant are considered, respectively the Barus and the Roelands expressions.Numerical models are developed for the initialization and calculation of the tangential traction inside the EHD lubricant film, for both rheological models. Some preliminary results are presented.