Influence of thermal shear localization on elastohydrodynamic contacts

Abstract

The temperature in elastohydrodynamic contacts determines the resistance of the lubricant film. Therefore, an efficient assessment of the scuffing risks requires accurate contact temperature prediction. The work presented in this paper makes use of a simple temperature model to investigate the influence of thermal shear localization on the temperature distribution in lubricant films. The model incorporates a multilayer lubricant film representation for the heat equation solution. The paper includes an original heat repartition factor expression and a simple formula for handling intermediate values of the Peclet number. The study also integrates an inlet temperature rise equation. The temperature predictions for sliding/rolling conditions are compared to published numerical results neglecting the shear localization influence. The results agree remarkably well; for the evaluations presenting the higher absolute difference, the correspondence remained over 94% and 95% for the maximum and mean temperatures, respectively. For the tested conditions, subsequent inclusion of the thermal shear localization contribution reveals that the shear localization augments the mean film temperature, while, depending on the pressure, the shearing zone occupies between 50 to 70% of the film thickness.

A study of thermal effects in EHL rheology and friction using infrared microscopy

“…This information is a vital complement to numerical models used to prevent component failure and optimise performance. These numerical models include CFD ones to understand EHL rheological behaviours [4][5] [6] [7], rheological ones to predict friction [8] [9] and mathematical ones to predict the contact surface thermal properties [10] and temperature effects [11] [12]. In summary, the temperature rise is the major detection index of friction heat generation and has played an indispensable role in tribology research during the last three decades [13] [14].…”