Analysis of Condensation Heat Transfer Enhancement on Hydrophobic-Hydrophilic Surfaces with Different Contact Angles

• Main Authors: Kai-HsiangWu, 吳凱翔
• Other Authors: Tzong-Shyng Leu
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/f79yk9

碩士 === 國立成功大學 === 航空太空工程學系 === 107 === This study investigates the effect of surface condensation heat transfer (CHT) gain with different contact angles, and confirms through theoretical analysis and experimental comparison that the larger the static contact angle in dropwise condensation is, the smaller the heat flux is. This study also combines the design of the hydrophilic-hydrophobic hybrid surface to enhance the CHT effect. Surface modification technology based on screen printing technique is used to fabricate CHT surfaces, including hydrophobic surfaces with 4 different static contact angles and hydrophilic-hydrophobic hybrid surfaces with 15 sets of different hydrophilic widths and hydrophobic widths of the matching. In terms of hydrophobic surface experiments, the results show that the surface with a static contact angle of 100° has best CHT effect. In terms of hydrophilic-hydrophobic hybrid surface experiments, the results show that the hydrophilic surface width of 200 μm with the hydrophobic surface width of 300 μm has the best gain ratio, compared with the hydrophobic surface can increase the heat flux by about 10%. In today's development environment focusing on energy efficiency, the results of this study are valuable and can be applied to CHT systems such as heat exchangers.