报告了R-134a和酯润滑剂混合物在12.7 mm（1/2 in.）管内蒸发和冷凝期间的平均传热系数和压降外径。本文的目的是评估R-134a-润滑剂混合物在这些管中的性能，并确定微翅片管的性能优势。12.7毫米（1/2英寸）管子的性能优势将外径与直径为9.52毫米（3/8英寸）的较小管子进行比较外径。使用的润滑剂是169 SUS季戊四醇酯混合酸润滑剂。混合物中的润滑剂浓度在0%到5.1%之间变化。平均传热系数为12.7毫米（1/2英寸）微翅片管比12.7毫米（1/2英寸）的微翅片管高50%到150%光滑管，而微翅片管中的压降比光滑管中的压降高5%到50%。添加润滑剂会降低所有情况下的平均传热系数，但在低润滑剂浓度下蒸发时除外。 随着润滑剂的加入，压降总是增加。实验结果还表明，与光滑管相比，管直径对微翅片管的性能效益有一定影响。引文:ASHRAE交易，1998年，第104卷，pt。1A，旧金山

The average heat transfer coefficients and pressure drops during evaporation and condensation are reported for mixtures of R-134a and an ester lubricant in tubes of 12.7 mm (1/2 in.) outer diameter. The objective of this paper is to evaluate the performance of the R-134a-lubricant mixtures in these tubes and determine the performance benefits of the micro-fin tube. The performance benefits of the tubes with 12.7 mm (1/2 in.) outer diameter are compared to those of smaller tubes with 9.52 mm (3/8 in.) outer diameter. The lubricant used was a 169 SUS penta erythritol ester mixed-acid lubricant. The lubricant concentration was varied from 0% to 5.1% in the mixture. The average heat transfer coefficients in the 12.7 mm (1/2 in.) micro-fin tube were 50% to 150% higher than those for the 12.7 mm (1/2 in.) smooth tube, while pressure drops in the micro-fin tube were 5% to 50% higher than in the smooth tube. The addition of lubricant degraded the average heat transfer coefficients in all cases except during evaporation at low lubricant concentrations. Pressure drops were always increased with the addition of lubricant. The experimental results also indicate that tube diameter has some effect on the performance benefits of the micro-fin tube over that of the smooth tube.