4.7 Article

Surface roughness variation effects on copper tubes in pool boiling of water

出版社

PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.ijheatmasstransfer.2020.119399

关键词

Pool boiling; Surface roughness; Hydrophobic pattern; Screen-printing technique; Wall super-heat; Boiling heat transfer coefficient; Critical heat flux; Heterogeneous wettable surfaces

资金

  1. Ministry of Science and Technology, Republic of China (Taiwan) [105-2221-E-002-107-MY3]

向作者/读者索取更多资源

Results showing the effects of varying the surface roughness on copper tubes in pool boiling of water are presented in this study. To obtain different surface roughness values of each sample, the copper tubes were rotated with an electric rotor and sanded using sandpaper of different grit sizes. The average surface roughness values of the plain copper tubes were in the range 0.032-0.544 mu m. All experimental samples were horizontally oriented, and experiments were carried out in ambient conditions up to a moderate heat flux regime (450 kW/m(2)). Moreover, for a comparative analysis, a sample with a rough surface and hydrophobic patterns was included in this study. Compared with the smoothest surface, the aforementioned rough sample exhibited a heat transfer coefficient that was up to a factor 1.5 higher for the highest evaluated heat flux. These findings show that even small increments in the surface roughness along with the addition of hydrophobic patterns can significantly lower the wall superheat temperature and increase the heat transfer coefficient of copper tubes. Furthermore, supported by high-speed imaging of the experiment, it was observed that increasing the surface roughness caused bubbles to depart when their diameter was larger, and the nucleation site density and bubble departure frequency increased. In contrast, the rough surface with hydrophobic patterns exhibited the best overall enhancement, including the characteristics mentioned above of the rough surfaces along with a uniform distribution of the bubbles around the surface. (C) 2020 Elsevier Ltd. All rights reserved.

作者

我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。

评论

主要评分

4.7
评分不足

次要评分

新颖性
-
重要性
-
科学严谨性
-
评价这篇论文

推荐

暂无数据
暂无数据