Assessment of Thermal Effects on Mixed Elastohydrodynamic Lubrication Line Contact by Outlet Lubricant Temperature

Abstract

The elastohydrodynamic (EHD) lubrication straight line contact conjunction is studied to evaluate the mixed lubrication heat generation experimentally over bordering operating conditions in a disc-on-disc machine. An experimental investigation is carried out using an accessory device that collects and measures the outlet lubricant temperature. The experimental results show the typical transition from mixed to elastohydrodynamic lubrication, tracking the difference of outlet lubricant temperature and the total average full-film EHD temperature. A new variable coupling flash temperature was introduced as an in situ approach to demonstrate the lubricant capacity of removing heat from asperity interaction in mixed lubrication contacts. It was possible to estimate the metal–metal contact area in mixed lubrication by coupling flash temperature as a direct correlation to the true flash temperature in relation to correspondence to final surface roughness characterizations.

Keywords:

• EHD
• micro-EHD
• mixed lubrication
• outlet lubricant temperature
• thermal effects in mixed lubrication
• traction

Acknowledgements

The authors express their gratitude to the Laboratory of Technology and Heat Transmission (LTTC), Department of Mechanical Engineering, Polytechnic, COPPE, Federal University of Rio de Janeiro, and Fluxo Tecnologia Ltda, Rio de Janeiro, Brasil, for the loan of equipment.

Additional information

Funding

This study was partially financed by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior–Brasil (CAPES), Finance Code 001 and by Conselho Nacional de Desenvolvimento Científico e Tecnológico–Brasil (CNPq).