Abstract An experimental investigation was conducted to evaluate heat transfer performance of several enhanced surface tubes during in-tube evaporation and condensation of R410A; results were then compared to the results of a smooth tube. Tubes considered in this evaluation included: smooth; herringbone and helix micro-grooves; herringbone-dimple and hydrophobic; all the tubes evaluated have the same external diameter of 12.7 mm. Experimental condensation and evaporation results were acquired at saturation temperatures of 318 K and 279 K, respectively. The mass velocities varied in the range of 40–230 kg m−2 s−1; vapor quality decreased from 0.8 to 0.2 for condensation and 0.2 to 0.8 for evaporation. Moreover, heat fluxes increased with mass velocity. Condensation heat transfer coefficients (HTCs) are enhanced by 40%–73%, with the dimpled herringbone-finned tube (EHT-HB/D) exhibiting the highest HTC among five tested tubes. The herringbone grooves can help lift the accumulated condensate along the circumference in addition to producing the drainage effects; dimples produce condensate turbulence and the droplet entrainment. For the evaporation, hydrophobic herringbone tube (EHT-HB/HY) provides the best thermal performance; its HTCs are 4%–46% larger than those of the smooth tube. This enhancement may be attributed to the expanded heat transfer area and the increased nucleation sites.

中文翻译：

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3-D增强管内冷凝和蒸发传热分析

摘要 对R410A管内蒸发冷凝过程中几种增强表面管的传热性能进行了实验研究；然后将结果与光滑管的结果进行比较。本次评估中考虑的管子包括： 光滑的；人字形和螺旋形微槽；人字形酒窝和疏水性；所有评估的管子的外径相同，均为 12.7 毫米。实验冷凝和蒸发结果分别在 318 K 和 279 K 的饱和温度下获得。质量速度在 40-230 kg m-2 s-1 范围内变化；蒸汽质量从冷凝的 0.8 降至 0.2，蒸发的从 0.2 降至 0.8。此外，热通量随着质量速度的增加而增加。冷凝传热系数 (HTC) 提高了 40%–73%，带有凹痕的人字形翅片管 (EHT-HB/D) 在五个测试管中表现出最高的 HTC。人字形凹槽除了产生排水效果外，还可以帮助沿圆周提升积聚的冷凝水；凹痕产生冷凝液湍流和液滴夹带。对于蒸发，疏水人字形管（EHT-HB/HY）提供最佳的热性能；它的 HTC 比光滑管的 HTC 大 4%–46%。这种增强可能归因于扩大的传热面积和增加的成核位置。对于蒸发，疏水人字形管（EHT-HB/HY）提供最佳的热性能；它的 HTC 比光滑管的 HTC 大 4%–46%。这种增强可能归因于扩大的传热面积和增加的成核位置。对于蒸发，疏水人字形管（EHT-HB/HY）提供最佳的热性能；它的 HTC 比光滑管的 HTC 大 4%–46%。这种增强可能归因于扩大的传热面积和增加的成核位置。