Abstract The condensation heat transfer of moist air plays an important role in industries and daily life. However, the presence of non-condensable gases makes it difficult for steam to condensate on a cooling surface. According to previous studies, a three-dimensional (3-D) finned tube and dropwise condensation can both increase the heat transfer performance. To increase the condensation heat transfer of moist air, this study combined these two methods and experimentally studied the condensation heat transfer of moist air outside 3-D finned tubes with different wettability values. The effects of the 3-D fins and surface wettability on the heat transfer process under different steam mole fractions, moist air temperatures, and cooling water inlet temperatures were determined and analysed in detail. The experimental results showed that a hydrophilic 3-D finned tube could achieve the highest heat transfer coefficient, which was up to 94% higher than that of a hydrophilic smooth tube. In addition, the heat flux and heat transfer coefficient increased with decreases in the moist air temperature and cooling water inlet temperature, or with an increase in the steam mole fraction. Droplet retained between 3-D fins increased the diffusion resistance of water steam and the conductive thermal resistance.

中文翻译：

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不同润湿性3D翅片管外湿空气冷凝传热特性

摘要 潮湿空气的冷凝传热在工业和日常生活中发挥着重要作用。然而，不可冷凝气体的存在使得蒸汽难以在冷却表面冷凝。根据之前的研究，三维 (3-D) 翅片管和滴状冷凝都可以提高传热性能。为了增加湿空气的冷凝传热，本研究将这两种方法结合起来，对不同润湿性值的3D翅片管外湿空气的冷凝传热进行了实验研究。详细确定和分析了 3-D 翅片和表面润湿性对不同蒸汽摩尔分数、潮湿空气温度和冷却水入口温度下传热过程的影响。实验结果表明，亲水性 3-D 翅片管可以获得最高的传热系数，比亲水性光滑管高 94%。此外，热通量和传热系数随着湿空气温度和冷却水入口温度的降低而增加，或随着蒸汽摩尔分数的增加而增加。保留在 3-D 翅片之间的液滴增加了水蒸汽的扩散阻力和传导热阻。