冷媒R-141b於氟化石墨烯表面改質平板之沸騰熱傳性能研究

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Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/81675

Title:	冷媒R-141b於氟化石墨烯表面改質平板之沸騰熱傳性能研究
Authors:	張博崴;Jhang, Bo-Wei
Contributors:	機械工程學系
Keywords:	奈米結構表面;石墨烯成長表面;改質石墨烯表面;池沸騰熱傳
Date:	2019-08-07
Issue Date:	2019-09-03 16:37:18 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究以冷媒 R-141b為工作流體在一大氣壓下進行實驗探討石墨烯結構於未成長銅片表面之池沸騰熱傳影響，實驗結果分為未成長銅片表面、石墨烯表面、氟化石墨烯表面之池沸騰熱傳，共三部份做探討。於池沸騰熱傳實驗結果顯示在高熱通量有石墨烯成長的表面有較高的熱傳性能，並且在實驗中使用高速攝影機可視化觀察沸騰情況，從影片觀察中可以發現石墨烯表面沸騰時產生的汽泡相較於未成長銅片表面有較大的汽泡產生，而對於沸騰增強原因是因為石墨烯表面對表面接觸角的改變。石墨烯成長表面的接觸角從14o增加到19o，而銅片表面有許多大小不同的孔洞，對於相同尺寸的孔洞，大接觸角表面較能關不凝結氣體在孔洞中，成為有效的成核孔洞，進而提升沸騰時表面汽泡密度，增加沸騰熱傳。石墨烯表面池沸騰的臨界熱通量提升，需要從動態實驗觀察不同熱傳表面對於汽泡生成時間長短討論，對於汽泡離開表面需要時間越長，代表在高熱通量時汽泡容易結合在一起，成大汽泡後造成區域燒乾的問題。燒乾對於電子設備有很大的影響，因此在石墨烯提高界熱通量的效能也值得作為電子散熱提升的使用。 ;In this study, the refrigerant R-141b was used as the working fluid at atmospheric pressure to investigate the influence of the boiling heat transfer with graphene coating on the copper plate. The experimental results were divided into smooth surface, graphene surface and fluorinated graphene surface. Biography, a total of three parts to discuss. The results of the boiling heat transfer experiment show that the surface with high heat flux and graphene growth has higher heat transfer performance, and the high speed camera is used to visually observe the boiling condition in the experiment. It can be found from the film observation that the surface of graphene coated for the number of bubbles generated is high erthan the surface of the plate. The reason for the increase in boiling result is due to the change in the surface contact angle of the graphene surface. The contact angle of the graphene growth surface increases from 13o to 22o, and there are many holes of different sizes on the surface of the copper plate. For the same size of the hole, the large contact angle surface can close the non-condensing gas in the hole and become an effective nucleation site. In turn, the surface bubble density during boiling is increased, and the boiling heat transfer is increased. The critical heat flux of graphene surface pool boiling increases. It is necessary to observe the different heat transfer surfaces from high speed film to calculate bubble frequency. The longer the bubble generation time is, the longer it takes for the bubbles to leave the surface, which means that the bubbles are easily combined at high heat flux. The problem of causing the area to dry out after forming a large bubble. Dry out has a great influence on electronic equipment, so the efficiency of increasing the heat flux in graphene is also worthy of being used as an electronic heat sink.
Appears in Collections:	[Graduate Institute of Mechanical Engineering] Electronic Thesis & Dissertation

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