Transient Thermal Elastohydrodynamic Modeling of Cam-follower Systems: Towards a More Realistic Performance Prediction
Résumé
The paper presents a detailed numerical analysis of the Thermal Elastohydrodynamic Lubrication (TEHL) of a cam-follower contact typically found in automobile racing. Under both low and high speed regimes, the transient response of such a contact under dynamic variations of load, surfaces velocity and radii of curvature was simulated using a shear-thinning lubricant. Comparisons between thermal and isothermal results on central and minimum film thicknesses and friction are given to highlight the outstanding influence of thermal effects. Furthermore, the paper reveals the formation and transport throughout the contact of a transient dimple responsible for a strong increase in lift around the zero entrainment velocity conditions (opening/closing flanks to nose transition). Pressure profiles as well as temperature, velocity and viscosity distributions across the film thickness are reported to show and analyze the underlying phenomena, known as “thermal viscosity-wedge”.