自再潤濕流體於薄型均溫板熱傳增益與工作流體性能分析之可視化研究

Visualization of Heat Transfer Enhancement of a Thin Vapor Chamber with Self-Rewetting Fluids and Working Fluids Performance Analysis

陳宇廷(Yu-Ting Chen)

指導教授 ： 朱錦洲

共同指導教授 ： 張建成(Chien-Cheng Chang)

國立臺灣大學/工學院/應用力學研究所/碩士(2020年)

https://doi.org/10.6342/NTU202003460

摘要

近年來，薄型均溫板(Vapor Chamber)被廣泛使用於手機以及各種電子產品當中進行散熱，雖然薄型均溫板傳熱能力可達金屬材料的數十倍到數百倍之多，但目前薄型均溫板還是會因為工作流體乾涸(dry-out)造成熱傳限制，為了讓薄型均溫板具有更好的熱傳效能，各大廠商也不斷研究改變均溫板的毛細結構與改變工作流體提升熱傳效能。
現今的均溫板大多都還是選用純水做為工作流體，因為純水具有較高優值(Figure of Merit,M)，但優值考慮到的流體參數只包含汽化潛熱、密度、黏滯係數與表面張力，並未考慮表面張力隨溫度變化之梯度，因此本研究將把表面張力隨溫度變化之梯度納入考量，藉以找到散熱效率較高之工作流體。
本實驗將量測各高碳醇水溶液之表面張力隨溫度變化之關係，以自再潤濕流體(Self-Rewetting Fluid)做為工作流體，利用馬蘭哥尼效應增加均溫板中工作流體由冷凝端回流至蒸發端之流量，避免乾涸(Dry-out)現象發生，提升最大熱傳量，並透過可視化熱測試系統觀察不同的工作流體在均溫板內運作情形，再藉由熱阻分析，找出不同瓦數下熱傳效益最高之工作流體及最佳毛細結構。且由實驗結果我們可得6%的叔丁醇水溶液與其它溶液相比在各輸入瓦數下都具有較好的熱傳表現，同時在30%開口率之毛細結構具有最好的熱阻表現。

關鍵字

薄型均溫板 ； 自再潤濕流體 ； 馬蘭哥尼效應 ； 表面張力 ； 可視化熱測試

並列摘要

In recent years, the vapor chamber has been widely used in mobile phones and various electronic products for heat dissipation. Although the heat transfer capability of the vapor chamber can reach tens to hundreds of times of metal materials, the current vapor chamber will still cause heat transfer restrictions due to the dry-out of the working fluid. In order to make the vapor chamber have better heat transfer performance, many major manufacturers are also constantly studying to change the capillary structure of the vapor chamber and change the working fluid Improve heat transfer efficiency.
Most of the current vapor chamber still use pure water as the working fluid, because pure water has a higher figure of merit (Figure of Merit, M). However, the fluid parameters considered by the figure of Merit only include latent heat of vaporization, density, viscosity coefficient and surface tension, the gradient of surface tension with temperature is not considered. Therefore, this study will take the gradient of surface tension with temperature into consideration to find a working fluid with higher heat dissipation efficiency.
This experiment will find the relationship between the surface tension of each high-carbon alcohol aqueous solution and the temperature change. Take self-rewetting fluid as the working fluid, and use Marangoni effect to increase the flow of the working fluid from the condenser section to the evaporator section of the vapor chamber to avoid dry-out phenomenon occurs and the maximum heat transfer and observes the operation of different working fluids in the vapor chamber through the visualized heat testing system, and then through the thermal resistance analysis to find the working fluid with the highest heat transfer efficiency and the best capillary structure under different input watts . From the experimental results, we can get that the 6% tert-butanol aqueous solution has better heat transfer performance at each input watt compared with other solutions, and the capillary structure with 30% opening ratio has the best thermal resistance performance.

並列關鍵字

Vapor chamber ； Self-rewetting fluid ； Marangoni effect ； Visualized heat testing

參考文獻

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