之前对冷冻油混合物的蒸发和冷凝进行的研究已经扩展到光滑管和微翅片管中粘度更高的油的混合物。制冷剂为R-22，油为300 SUS环烷基矿物油，而之前的研究使用150 SUS油。试验段是一根外径为0.375 in（9.52 mm）、长度为12 ft（3.67 m）的水平直管，由周围环形空间中流动的水加热或冷却。蒸发期间的标称试验条件为37°F（3°C），冷凝期间的标称试验条件为105°F（41°C）。质量通量的变化范围为92000至294000 lb/h•ft²（125至400 kg/m²•s），油浓度的变化范围为0%至5%（按重量计）。对于蒸发和冷凝，蒸汽质量变化在15%到85%之间。与使用150 SUS油进行的试验不同，在某些情况下，传热增强30%以上，使用300 SUS油时，蒸发传热没有显著增强。 总的来说，传热在两个管中都会退化，在最大油浓度为5%时观察到的退化最大。微翅片管的最大降幅约为30%，光滑管的最大降幅约为20%。使用300 SUS ofl进行的冷凝试验产生的结果与使用150 SUS油进行的早期试验非常相似，传热总是随着浓度的增加而减少。两种管道的传热减少百分比相似。在油浓度为5%时，光滑管的减排量从10%左右增加到微翅片管的20%。引文:ASHRAE Transactions，第95卷，pt。1989年，芝加哥

Previous work performed on the evaporation and condensation of refrigerant-oil mixtures has been extended to cover mixtures of a more viscous oil in a smooth tube and a micro-fin tube. The refrigerant was R-22 and the oil was a 300 SUS naphthenic mineral oil, while the previous study used 150 SUS oil. The test section, which was heated or cooled by water flowing in a surrounding annulus, was a straight, horizontal tube with an outside diameter of 0.375 in (9.52 mm) and a length of 12 ft (3.67 m). Nominal test conditions were 37°F (3°C) during evaporation and 105°F (41°C) during condensation. Mass fluxes were varied from 92,000 to 294,000 lb/h • ft2(125-400 kg/m2• s) and the oil concentration was varied from 0% to 5% by weight. For both evaporation and condensation, the vapor quality change was between 15% and 85%.Unlike tests with 150 SUS oil, in which heat transfer was enhanced by more than 30% in some cases, there was no significant enhancement of evaporative heat transfer with 300 SUS oil. In general, the heat transfer was degraded in both tubes, with the greatest observed degradation at the maximum oil concentration of 5%. The maximum decrease was about 30% for the micro-fin tube and about 20% with the smooth tube. Condensation tests with 300 SUS ofl produced results very similar to earlier tests with 150 SUS oil, with heat transfer always decreasing as off concentration increased. The percentage decrease in heat transfer was similar for both tubes. At 5% oil concentration, the decrease r~nged from about 10% with the smooth tube to 20% with the micro-fin tube.