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標題: | 熱板之毛細熱傳能力改善分析 Improvement on Capillary Heat Transfer in Vapor Chamber |
作者: | Szu-Wu Chen 陳思吾 |
指導教授: | 朱錦洲(Chin-Chou Chu) |
關鍵字: | 薄型熱板,滲透度,等效毛細半徑,毛細自吸方法,流體優值, Ultra-thin Vapor Chamber,Permeability,Effective pore radius,Capillary rise method,fluid merit, |
出版年 : | 2017 |
學位: | 碩士 |
摘要: | 高熱傳導性的元件如:熱管和熱板,是目前業界主流的散熱科技元件,本研究主要目的是經由毛細自吸實驗,來探討滲透度以及等效毛細半徑。近年來各種 科技產品皆走向輕薄且高處理性能的趨勢,傳統的熱板已經慢慢無法導入市場,必須藉由超薄型熱板產品才足以提供市場需求,然而在薄型結構內的空間設計可 說是錙銖必較,因此如何在有限空間內設計出擁有優質的毛細能力之結構將是未來製成和設計技術上的挑戰。
熱板內部工作的原理,一般包含著三個重要的因子:(1) 流體優值為內部工作流體的參考依據,目前一般來說都是用水(2) 滲透度與等效毛細半徑之比值a(3) 熱板的幾何結構參數。為了判斷熱板工作性能,本論文提出兩個主要之實驗來測定毛細性能,首先吾人架設出一套系統能夠利用觀察毛細自吸高度進而推算出其滲透度與等效毛細半徑之定量分析方法,利用此方法就能比較出毛細性能之優劣,再者利用儀器量測其接觸角,將其結果做結合得到:當接觸角越低時(接近0度)其毛細性能較好,a值約為1.4 ,然而,當接觸角越高時毛細能力受其影響而下降,a降為0.5。 大部分業界一般所使用的是200目無氧銅網,因此本研究將長度100mm、寬度50mm、厚度0.09mm之200目無氧銅網進行不同種設計開孔,發現在開孔率50%下有最好的毛細自吸結果。綜合以上,在一毛細孔徑流道內,若是處處都是毛細結構,雖然毛細能力好,但伴隨而來的流阻也相對大,在這些因子之間找到平衡最佳化以及最適當的參數,進而提升熱板的工作性能。 High effective thermal conductivity element such as heatpipes, vapor chambers are major thermal solution technologies in Industry. The main purpose of this study is to investigate the permeability and the effective pore radius by conducting capillary-rise experiments. Recently, a variety of high-tech merchandise were so designed to achieve ultra-light, extremely thin and high processing performance. Therefore, the traditional vapor chambers are gradually losing their markets, especially in the mobile industry because only the thinnest vapor chamber meets the demands of the market. However, the spatial design inside the thin structure of vapor chamber is a critical problem. Hence, how to manufacture a vapor chamber with tiny volume and high-quality capillary force has become a challenge in both technical design and mass production. There are three significant factors involved with the performance of vapor chambers: 1. the ratio of fluid merit - in general the DI-water is used in order to keep the cost down. 2. the ratio of permeability and effective pore radius (a), and 3. the geometric structures of the vapor chamber. For the sake of comparing the ability of capillary performance, this study is divided into two experiments. In the first place, we set up a system to measure the parameter of capillary performance . Secondly we measure the contact angle (theta) of a vapor chamber. As a result, the contact angle decreases as the capillary performance increases and vice versa . Currently most of the industries are using 200 mesh copper in the vapor chamber. In this study, we design the various wick types on 200 mesh copper. We found that the best capillary performance occurs at 50% wick type for a single layer, which is even better than the bilayer mesh copper. In a vapor chamber, the wick structure's performance increases while the frictional loss increases as well. Hence, it is worwhile to find the appropriate parameters, which balances/optimizes the wicks design, aiming to enhance the overall performance of a vapor chamber. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/59925 |
DOI: | 10.6342/NTU201700235 |
全文授權: | 有償授權 |
顯示於系所單位: | 應用力學研究所 |
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