一般電腦產品的散熱模組設計，多數為熱管加上風扇及鰭片所組合，其中熱導管為散熱設計中關鍵零件之一；常見之熱管多以純銅為容器、純水為工作液體，但銅之密度為8.9 g/cm3，其單位重量非常重，在電子產品之發展趨勢走向輕量化及薄型化下，不利於3C產品的輕量化設計，所以散熱器的減重變成一個重要的研究題目。本研究之目的為熱管輕量化及薄型化，實驗中採用鋁銅複合材料為熱管容器，可較相同管壁厚度的純銅熱管減少約60%的重量，並研究規劃其製造流程，以及建立鋁熱管之最大熱傳量測試平台。
本實驗設計製造之鋁熱管，因內部設計有一層薄薄之純銅材料層，可隔絕工作液體與主材質鋁殼體直接接觸，而得以突破一般鋁熱管研究常遇到之工作液體相容性問題；所以就熱管的最大熱傳量而言，實驗顯示可完全達到與傳統銅水熱管相同的性能，在熱管厚度2.2mm甚至可達到最大熱傳量30瓦。至於在薄型化鋁熱管設計與充填水量的關係分析探討，由實驗結果發現在一般厚度時，增量充填確實會增加鋁熱管的最大熱傳量，但當內部空間高度小於0.9mm時，則增加水量過多反而會讓最大熱傳量下降；所以當熱管做薄型化設計時，進行充填水量的最佳化工作，必須將壓扁後熱管截面的幾何形狀列入考慮。

In fulfilling consumer’s requirement on reducing size and weight of mobile devices, especially the notebook, tablet, and cell phone, has generated a urgent demand for manufacturing the light-weight Aluminum heat pipe. Thus, the purpose of this study is to design and manufacture the Al heat pipe that uses pure water as the working medium. Obviously, the major advantages in utilizing Al heat pipe include the lighter weight and cheaper cost compared to the traditional copper heat pipe. However, there are several technical challenges, such as the welding, corrosion, and compatibility issues in using Al as the heat pipe container. Firstly, a thin copper layer is attached closely to the inside wall of Al pipe for preventing the direct contact with water; thus the corrosion and compatibility issues between water and Al can be solved. Also, the YAG laser welding technology is introduced for sealing two ends of Al heat pipe. Furthermore, the systematic procedures for manufacturing and testing this Al heat pipe are proposed and set up successfully.
Later, the amount of working medium and the flattened thickness of heat pipe are investigated for identifying the optimum values to yield the highest maximum heat transfer rate. Consequently, it is found that the maximum heat transfer rate enlarges for an increasing working-medium amount under a normal flattened thickness. Nevertheless, a decrease on maximum heat transfer rate is observed for the case of filling too much water when the height of vapor channel inside the heat pipe is less than 0.9 mm. Besides, the results illustrate that heat dissipating capability (30 watts) of the optimized heat pipe is almost identical to that of the traditional copper heat pipe with a 2.2 mm flattened thickness. Therefore, it is suggest that determining the optimized amount of working medium should take into account the cross-sectional geometry of heat pipe. In summary, this study presents a reliable and systematic scheme to fabricating the Al heat pipe.

[1]http://www.lanl.gov/science/NSS/issue1_2011/story6full.shtml
[2]R. S. Gaugler, “Heat Transfer Devices”, U. S. Patent 2,350,348, 1944.
[3]G. M. Grover, T. P. Cotter, and G. F. Erikson, “Structures of Very High Thermal Conductivity”, Journal of Applied Physics, Vol. 35, pp 1990-1991, 1964.
[4]T. P. Cotter, “Theory of Heat Pipe,” Los Alamos Scientific Laboratory Report No. LA-3246-MS, 1965.
[5]C.L. Tien and K.H Sun, “Minimum Meniscus Radius of Heat Pipe with a Wicking Materials”, International Journal Heat Mass Transfer, Vol. 14, pp 1853-1855, 1970.
[6]C.A. Busse, “Pressure Drop in the Vapor Phase of Long Heat Pipes”, Proc. IEEE Conf. of Thermionic Conversion Specialists, Palo Alto, CA, pp. 391-398, 1967
[7]T. P. Cotter, “Principles and Prospects for Micro Heat Pipes,” Porc. 5th Int. Heat Pipe Conf., Tsukuba, Japan, pp. 328-335, 1984.
[8]依日光譯, “熱管技術理論實務” 日本熱管技術協會編，復漢出版社社，1986年。
[9]K. T. Feldman, “Flat Plate Heat Pipe with Structure Wicks” U. S. Patent 3,613,778, 1969.
[10]H. Van Ooijen and C. J. Hoogendoorn, “Vapor Flow Calculation in a Flat Heat Pipe,” AIAA J., Vol. 17, pp. 1251-1259, 1979.
[11]黃玉年，“矽質為熱管之研製與測試”，淡江大學機械工程研究所碩士論文，1999年。
[12]劉榮祥，“燒結式微熱管之製造與實驗研究”，台灣科技大學機械工程研究所碩士論文，2003年。
[13]劉秉翰，“高分子毛細結構在迴路式熱管之應用研究”，台灣大學機械工程研究所碩士論文，2005年。
[14]許智穎，“燒結與溝槽式複合毛細結構微熱管之製造與實驗研究”，台灣科技大學機械工程研究所碩士論文，2008年。
[15]甯道遠，“鑽石/銅複合材料製備毛細微結構應用於平板式熱管”，國防大學機械工程研究所碩士論文，2010年。
[16]P. D. Dunn and D. A. Reay, Heat Pipes, 4th Edition, Headington Hill, England, 1994.
[17]S. W. Chi, “Heat Pipe Theory and Practice”, McGraw-Hill, Washington, New York, 1976.
[18]E. K. Levy, “Theoretical Investigation of Heat Pipes Operating at Low Vapor Pressure,” Journal of Engineering for Industry, Vol. 90, pp. 547-552, 1968.
[19]C. A. Busse, “Theory of the Ultimate Heat Transfer Limit of Cylindrical Heat Pipes,” Int. J. Heat Mass Transfer, Vol. 16, pp. 169-186, 1973.
[20]T. P. Cotter, “Heat Pipe Startup Dynamics”, Proc. IEEE Conf. of Thermionic Conversion Specialists, Palo Alto, CA, pp 344-348, 1967.

[21]A. Faghri, “Heat Pipe Science and Technology”, Taylor and Francis, Washington, DC, 1995.
[22]S. B. Riffat, S. A. Omer, and X. L. Ma, ”A Novel Thermoelectric Refrigeration System Employing Heat Pipe and a Phase Change Material”, SDOS Renewable Energy, pp. 313-323, 2001.
[23]http://www.gdcopper.com/gd/en/display_pzbz.asp?Action=ShowChild&ClassID=12&NClassID=24
[24]H. J. Long, Z. Xin, C. J. Cong, and L. Yong “Forming Defects of Axial Inner Micro-grooved Copper Tube Through Two-Split Dies Rotary Swaging Process” Materials Science & Technology, Vol. 20 , No.4, pp116-120, 2012.
[25]William T. Silfvast, ”Laser Fundamentals”, the Press Syndicate of the University of Cambridge, New York, 2004.
[26]TTMA, ” Standard Testing Method for the Performance of Miniature Heat Pipes”, 2012.
[27]F. J. Higuera, A. Medina, and A. Liñán, ”Capillary Rise of a liquid Between Two Vertical Plates Making a Small Angle”, Physics of fluids 20, 102102, 2008.