Abstract
The film-forming properties of several refrigeration lubricants placed in the pressurized refrigerant atmosphere has been investigated by the interferometric test rig equipped with the pressurized vessel. The results showed that film thicknesses formed by the lubricants decreased as refrigerant pressure increased. However the decreased rates were different from one oil/refrigerant combinations to others. This was due to differences in solubility of the rifrigerants into oils and/or in the oil's viscosity. The results also showed that the measured film thicknesses of oil/refrigerant mixtures were thinner than those estimated from the viscosity data. The authors discussed the viscosity-pressure coefficient variability within the refrigerant concentration.