Surface tension of HFC-161 and compressor oil mixtures

The surface tension of environmental-protection refrigerant ethyl fluoride (HFC-161) and its mixtures with commercial lubricant RL68H, SUNISO SL-32S and SUNISO 3GS were determined in the temperature range from (242 to 370)K by differential capillary rise method. The mass fraction of oil in mixtures is below 2.0%. All the surface tensions of mixtures were correlated as a function of temperature and mass fractions, which can be easy to apply to relevant refrigeration design. Before that, the experimental apparatus was verified by measuring the surface tension of HC-600a. The temperature and surface tension uncertainty were within 12mK, 0.2mN ⋅ m−1, respectively.