平板式熱管毛細組織性能之研究

本研究針對網格式、凹槽式及燒結式毛細組織對於熱管熱阻抗之影響，以純水及甲醇進行實驗研究；量測平板式熱管之溫度分佈與熱傳性能。本研究在網格式平板熱管的熱傳性能研究中，使用紅銅作為熱管的主體結構，其內的毛細組織為100及120目的網格。在熱管的熱傳性能研究中，在紅銅平板上製作間距0.55mm深0.3mm之V字型溝槽，另以凹槽式平板加上100或120目的網格作為毛細組織。在燒結式平板熱管的熱傳性能研究中，使用紅銅作為熱管的主體結構，其內的毛細組織為粉末燒結而成的孔隙組織。以上三種毛細組織皆使用純水、甲醇做為工作液體，加熱量在10~40W之間不等。實驗結果發現本研究所用之熱管毛細組織以溝槽加網格最佳、溝槽式次之、燒結式及網格式較差；經分析其性能與其穿透率、有效毛細半徑有關。絕大部分數據顯示工作液體以甲醇較純水好；經本研究分析，其主因為甲醇在網格間的接觸角較小，毛細作用較強所致。當熱管操作為水平放置時之性能比蒸發器向上傾斜8度佳。傾斜角度(重力)對冷凝阻抗的影響較蒸發阻抗大。在25%，33%，50%三種充填率中甲醇以25%最佳，純水則以50%最佳。本研究提出包含接觸角效應之優點數修正公式，在使用網格為毛細組織時，應依流體之接觸角進行修正，才能有效反應熱管性能。

關鍵字

平板式；熱管；毛細組織；熱阻抗

並列摘要

In this study, the effects of capillary structure, charge volume, working fluid, and inclination angle on the plate heat pipe performance are investigated. A test apparatus was designed to measure the temperature distribution on the plate heat pipe for the evaluation of thermal performance at 10-to-40 W heat input. The copper based plate heat pipes having four types of capillary structures were investigated experimentally using pure water or methanol as working fluid. The four types of capillary structures are: (1) triangular grooves, (2) #100 or #120 meshes, (3) mesh on a grooved plate, and (4) sintered porous coating. The working fluid occupies 25%, 33%, or 50% of the heat pipe internal space. In addition to horizontal orientation, the heat pipes were tested with the evaporator section elevated 8 degree. The evaporator, adiabatic and condensation resistances of the heat pipe were calculated and analyzed. The present experimental results show that the mesh on a grooved plate is the best capillary structure and the mesh is the worst. The heat pipe having triangular grooves has the second best performance. For most cases, the total resistance of the heat pipe containing methanol is lower than that of the water heat pipe. The thermal performance of the present heat pipes is slightly degraded as the evaporator of heat pipe tilts up 8o. The best charge volume fraction is 25% for methanol and 50% for water. A modified “Figure of merit”, which accounts for the effect of contact angle of mesh structure, is proposed.

並列關鍵字

Flat Plate Heat Pipe ； Capillary Structures ； and Thermal Resistance

參考文獻

[4]Faghri, A., Heat Pipe Science and Techniology, chapter 1、2、3、4, 1995

[5]Hopkins, R. , Faghri, A. and Khrustalev, D., “Flat Miniature Heat Pipe with Micro Capillary Grooves”, Journal of Heat Transfer, Vol.121, pp.102-109. , 1999

[6]Huang , X. Y. and Liu, C. Y., “The Pressure and Velocity Fields in the Wick Structure of a Localized Heated Flat Heat Pipe”, International Journal Heat Mass Transfer, Vol 39, No 6, pp.1325-1330. , 1996

[7]Khrustalev, D. and Faghri, A., “Thermal Analysis of a Micro Heat Pipe”, Journal of Heat Transfer, Vol.116, pp.186-197. , 1994

[9]Ma, H. B. and Peterson, G. P., “Experimental Investigation of the Maximum Heat Transport in Triangular Grooves”, Transactions of the ASME, Vol.118, pp.740-746. ,1996

國際替代計量

平板式熱管毛細組織性能之研究

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