Exploring the cooling capability of self-rewetting fluid deposited on the cold end of a copper strip with horizontal temperature gradient

• Main Authors: Chia-Yin Hung, 洪嘉吟
• Other Authors: Chen-li Sun
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/9xmnz8

碩士 === 國立臺灣大學 === 機械工程學研究所 === 107 === This study aims at applying the inverse Marangoni convection to cooling augmentation of a super-hydrophilic copper strip with a horizontal temperature gradient. The self-rewetting fluid used herein is the 0.2%wt 1-heptanol dilute aqueous solution and there are two different supplied quantity: 1 ml and 1.5 ml. The horizontal temperature gradient is varied by adjusting the inlet temperature of coolant and the initial temperature of the hot end. We find that the inverse Marangoni convection is able to cool the hot end effectively and result in higher accumulated cooling amount comparing to water. For a given initial temperature of the copper strip in the hot end, warmer coolant at the results in lower inlet temperature gradient and therefore weaker inverse Marangoni convection. When temperature gradient exceeds 3°C cm-1 on the other hand, applying less working fluid produces a higher temperature gradient, therefore, the stronger inverse Marangoni convection and the higher accumulated cooling amount. However, a temperature gradient less than 3°C cm-1 leads to very weak inverse Marangoni convection, and the low temperature of copper strip in the hot end makes the change in sensible heat of fluid dominate the heat transfer mechanism. As the result, 1.5 ml of working fluid produces a higher accumulated cooling amount comparing to that of 1 ml. In addition, dryout can be effectively delayed by strong inverse Marangoni convection when 1 ml of the self-rewetting fluid is applied with a large temperature gradient in horizontal direction.