An Experimental Investigation on Thermal Performance of Ultra-thin Heat Pipe with Superhydrophilic Copper-braids

• Main Authors: Te-Hsuan Chen, 陳德璇
• Other Authors: 陳炳煇
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/jnnd8q

碩士 === 國立臺灣大學 === 機械工程學研究所 === 107 === This study investigated the thermal performance of an ultra-thin heat pipe (UTHP). The total thickness of the heat pipe was 1 mm. The wick structure was made of copper-braids which were combined by 288 copper wires. In order to improve the capillary ability of copper-braids, this study conducted a surface modification on the wick structure to obtain a superhydrophilic surface. This research was divided into three parts: the wettability of the wick, the filling ratio, and the variation of sectional lengths: condenser, adiabatic and evaporator. The experimental results showed that the superhydrophilic wick material can improve the thermal performance of the UTHPs. Besides, the filling ratio also plays an important role in the performance of the heat pipe, and the volume of the working fluid should be more than the pore volume of the wick structure. In this study, the filling ratio of 16.4% exhibited the best thermal performance on the UTHPs. Furthermore, the sectional lengths affect both the thermal resistance and the maximum heat transport rate (Qmax), especially for the adiabatic length. The results showed that the longer adiabatic length would increase the thermal resistance, but the longer condenser and evaporator length slightly decrease the thermal resistance. However, it was observed that the Qmax is degraded when the adiabatic length or condenser/evaporator length is longer because the Qmax is influenced by the effective length of heat pipe.