在光滑管和微翅片管内对冷冻油混合物的蒸发和冷凝进行了研究。制冷剂为R-22，油为粘度为150 SUS的环烷基矿物油。在整个试验条件范围内，油和制冷剂完全可混溶。外径为0.375 in（9.52 mm），长度为12 ft（3.67 m）的直线水平试验段通过周围环形空间中流动的水进行加热或冷却。油的质量浓度在0%到5%之间变化，质量通量在92000到294000 lb/h-ft²（125到400 kg/m²-s）范围内进行测试。蒸发温度为37华氏度（3摄氏度），入口和出口质量分别约为15%和85%。冷凝条件为105 F（41°C），标称入口和出口质量分别为85%和15%。 对于冷冻油混合物和纯制冷剂，微翅片管将蒸发和冷凝的平均传热系数提高了2.5倍。与纯制冷剂蒸发相比，对于光滑管和微翅片管，发现少量的油可以增强蒸发传热。在阈值浓度以上，添加的油量增加导致强化降低，但对于微翅片管，强化仍然大于表面积的增加。添加任何油都会导致两个管的冷凝传热降低。微翅片管的冷凝强化传热系数与油浓度关系不大。 单位:双引文:阿什雷交易，1988年，第94卷，第。德克萨斯州达拉斯1号

Evaporation and condensation of refrigerant-oil mixtures were studied both inside a smooth tube and a micro-fin tube. The refrigerant was R-22 and the oil was a naphthenic base mineral oil with a viscosity of 150 SUS. The oil and refrigerant were completely miscible for the entire range of test conditions The straight, horizontal test section, 0.375 in (9.52 mm) od with length of 12 ft (3.67 m), was heated or cooled by water flowing in a surrounding annulus. The oil mass concentration was varied from 0% to 5% and mass fluxes were tested over the range of 92,000 to 294,000 lb/h-ft2(125 to 400 kg/m2-s). Evaporation was at 37 F (3°C) with inlet and outlet qualities &approximately 15% and 85%, respectively. The condensation conditions were 105 F (41°C) with nominal inlet and exit qualities of 85% and 15%, respectively.The micro-fin tube increased the average heat transfer coefficients for both evaporation and condensation by as much-as a factor of 2.5 for refrigerant-oil mixtures as well as for pure refrigerant. For both smooth and micro-fin tubes, small quantities ofoil were found to enhance evaporation heat transfer in comparison with pure refrigerant evaporation. Above a threshold concentration, the addition of increasing quantities of oil caused the enhancement to decrease, but for the micro-fin tube, the enhancement remained greater than the increase in surface area The addition of any oil caused the condensation heat transfer to decrease for both tubes. The micro-fin tube’s heat transfer enhancement factor for condensation showed little dependence on the oil concentration.Units: Dual