迴路式熱虹吸管之薄膜蒸發研究

Investigation of Thin Film Evaporation in Close Loop Thermosyphon

陳聖謙(Sheng-Cian Chen)

指導教授 ： 陳希立

國立臺灣大學/工學院/機械工程學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.01112

摘要

隨著電子工業的發展，電子產品不斷朝著高性能、小體積的方向發展，造成單位面積的發熱量卻是越來越高，產生散熱方面的問題，使得各種電子設備散熱系統因應而生。近幾年來，利用工作流體沸騰與冷凝之相變化以快速帶走熱量的方式被廣泛的應用在解決散熱問題上，迴路式熱虹吸系統即為其中之一。從相關文獻得知，迴路式熱虹吸系統的蒸發器在使用燒結表面及低充填率時會以熱傳性能極佳的薄膜蒸發機制散熱，並指出利用薄膜蒸發機制可設計出散熱效率極佳的蒸發器。
本研究針對迴路式熱虹吸系統設計一套完整的實驗方法，研究加熱功率、充填率、燒結板傾斜角度及燒結厚度對蒸發器熱傳性能的影響。實驗結果發現，蒸發器於不同操作條件下存在四種熱傳型態：(a)燒乾區、(b)薄膜蒸發區、(c)過渡區及(d)沸騰區，經由可視化實驗及理論推導進而得到完整的熱傳型態圖，並證實薄膜蒸發機制有優於沸騰機制的熱傳性能。比較不同熱傳型態圖得知，非水平型式擺設的燒結板擁有較水平型式更大的薄膜蒸發區域，此外，當燒結厚度增加時也明顯有助於擴大熱傳型態圖的薄膜蒸發區域，增進薄膜蒸發機制在實際應用時的使用彈性。

關鍵字

熱虹吸 ； 薄膜蒸發 ； 熱傳型態圖

並列摘要

With the growth of electronics manufacturing, electronic components become more powerful and the size of them tends to be smaller. It induces the challenge in thermal solution, and several kinds of electronic cooling methods are applied to conquer the thermal dissipation problem. In recent years, the applications of boiling-condensation heat transfer mechanism are widely used for the heat dissipation problem, and closed loop thermosyphon is one of them. It is found in a previous study that thin film evaporation, which has a great heat transfer capacity, occurs in the evaporator of closed loop thermosyphon system while a low fill ratio of working fluid and a sintered evaporation surface are adopted. The presented study focuses on the occuring mechanicsm of thin film evaporation with sintered surface for evaporator design.
This paper establishes a set of experimental methods for investigation and analysis of the loop thermosyphon system. The influences of heating power, fill ratio, tilt angle of sintered surface, and thickness of sintered structure to heat transfer performance of evaporator are under concern. The results show that the evaporator has four heat transfer patterns in different operating condition: (a)dry out, (b)thin film evaporation, (c)transition and (d)boiling. It is apparent that the heat transfer performance of thin film evaporation is better than boiling. By comparing different flow patterns, it shows that the sintered surface of non-horizontal type has larger thin film evaporation region than horizontal type and that thicker sintered structure is helpful to enlarge thin film evaporation region.

並列關鍵字

Thermosyphon ； Thin film Evaporation ； Heat transfer and flow Pattern

參考文獻

39. 蕭惟哲, 「兩相封閉迴路式熱虹吸散熱系統」，碩士論文，國立臺灣大學機械工程學研究所，民國九十四年六月（2005）

44. 江沅晉, 「微結構蒸氣腔體之研究與電子散熱應用」，博士論文，國立臺灣大學機械工程學研究所，民國九十四年六月（2005）

4. Maydanik, Yu. F., "Loop Heat Pipes – Development and Application," the SEMINAR of Department of Mechanical Engineering National Taiwan University, Oct. 2003.

5. Murthy, S. S., Joshi, Y. K. and Nakayama, W., "Single Chamber Compact Thermosyphons with Micro-Fabricated Components," Proceedings of the 7th Intersociety Conference on Thermal and Thermomechanical Phenomenon in Electronic Systems (I-Them), Las Vegas, NV, May 2000.

7. Ramaswamy, C., Joshi, Y. K. and Nakayama, W., "Thermal Performance of a Compact Two-Phase Thermosyphon: Response to Evaporator Confinement and Transient Loads," Journal of Enhanced Heat Transfer, Vol. 6, No. 2-4, pp. 279-288, 1999.