An experimental and modeling assessment of the HCFC-R123 refrigerant capabilities for lubricating rolling EHD circular contacts

Abstract

This work aims at investigating the capabilities of the hydrochlorofluorocarbon (HCFC)-R123 refrigerant for lubricating rolling elastohydrodynamic circular contacts. The viscosity pressure and temperature dependence of this fluid, used in oil-free compressors, are first studied in its liquid phase. Complementary data like density variations are taken from the thermo-physics literature. Besides, film thickness measurements using a ball-on-disk tribometer equipped with an interferometry facility have been performed under pure rolling conditions. For the same operating conditions, film thickness is then predicted from a numerical elastohydrodynamic model in which the viscosity and density dependencies with pressure and temperature are described using physics-based relationships, allowing a quantitative approach. The results obtained from the full numerical model, from the analytical elastohydrodynamic film-thickness expressions, and from the experiments show an acceptable agreement. They clearly reveal that indeed refrigerants can build up a reasonable film thickness for lubricating elastohydrodynamic rolling point contacts.