Pressurised chamber design for conducting rolling contact experiments with liquid refrigerant lubrication

A novel pressurised chamber was designed to construct a special purpose test rig to achieve saturated liquid state of refrigerants for lubricated rolling contact fatigue experiments. Traditional bench testing using refrigerants as the lubricant is difficult due to the gaseous phase at standard atmospheric conditions. Pressurising the concentrated contact test chamber is therefore necessary to evaluate at a liquid state and therefore simulate practical applications. The gas/liquid phase transitions have a significant influence on the lubricant properties and hence wear mechanisms. It is necessary to modify the wear test conditions for the Hydrocarbon (HC) and Hydrofluorocarbon refrigerants to obtain realistic simulation of refrigerator compressor tests. The chamber design and test rig are described in this paper. A preliminary experimental study of the influence of the HC (R600a) on rolling wear of the silicon nitride (Si₃N₄)/steel elements using the pressurised chamber is presented. Rolling fatigue test methods are adopted to measure the wear performance of silicon nitride/steel bearing materials. In this case the rolling wear mechanisms of Si₃N₄ were measured using R600a refrigerant lubrication.