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Conference Papers Year : 2014

R123 Refrigerant Lubrication of Rolling Contacts – An Experimental and Modelling Investigation

Abstract

1.INTRODUCTION Compressor rolling bearings in large chillers in air conditioning systems are normally lubricated with a mixture of oil and refrigerant, in general the dilution rate of refrigerant does not exceeds 20 %. However, in some new designs the oil has to be removed completely and the rolling bearings will be lubricated solely with refrigerant. Such a configuration requires to ensure that the mechanisms will operate satisfactorily and firstly, that a sufficient film thickness will separate the surfaces. 2.ABSTRACT In this study, a typically used refrigerant (R123) for oil-free compressors is characterized in terms of pressure and temperature effects on viscosity in its liquid phase. Complementary data like density were taken from the thermo-physics literature. The dependence of these parameters with pressure and temperature was described using physics-based relationships, allowing their integration into numerical models with good confidence. Besides, film thickness measurements using a ball-on-plate tribometer equipped with an interferometry facility [1] have been performed. Finally, an existing FEM numerical model [2] for Elastohydrodynamic Lubrication (EHL) has been used to predict both film thickness and friction. Considering film thickness, the results from the model and the experiments are in good agreement. They clearly show that indeed refrigerants can build-up a reasonable film thickness for lubrication. Extensive numerical simulations were then carried out for investigating the possibility to derive specific film thickness analytical expressions based on the real rheological behaviour and compressibility of the refrigerant. Compared with a previous work [3], this should lead to a progress in the quantitative prediction of film thickness in EHD contacts lubricated by a refrigerant.
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Dates and versions

hal-01079487 , version 1 (02-11-2014)

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  • HAL Id : hal-01079487 , version 1

Cite

Philippe Vergne, Nicolas Fillot, Nathalie Bouscharain, Nicolas Devaux, Guillermo E. Morales Espejel. R123 Refrigerant Lubrication of Rolling Contacts – An Experimental and Modelling Investigation. 41st Leeds-Lyon Symposium on Tribology "Integrated Tribology", The University of Leeds, Sep 2014, Leeds, United Kingdom. ⟨hal-01079487⟩
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