二元混合流體應用於增益薄型均溫板蒸發熱傳之可視化研究

Abstract

現今的電子產品持續朝著輕薄與多功能的方向演進，使得產品內 部 CPU的運作時脈不斷提升，引發了許多高發熱量的問題，再者根據研究指出，電子產品的損壞原因有 55%來自於內部過高的溫度，其次才是人為與潮濕的損壞，由此可知，散熱對科技的發展扮演了不可或缺的角色。 但在追求產品輕薄化的同時，勢必會影響均溫板內部的流體質量，較少的流體會造成均溫板無法承受較高的瓦數，所以本實驗的研究目的在於，利用二元混合流體的馬蘭哥尼效應，加強均溫板毛細結構內冷端往熱端的流動，延緩乾涸現象發生，提升臨界熱傳量。為了方便觀察均溫板內部乾涸現象，本實驗也架設了可視化裝置，可以透過 PC塑膠上蓋板清楚觀測內部的相變化與乾涸情形。 實驗流體方面，採用純水、正丁醇、正戊醇、正己醇這四種 流體，改變濃度方面，選用各醇類的最大溶解度，正丁醇採用 2~6%；正戊醇採用 1~3%；正己醇採用 0.6%，改變以上的流體與濃度，並以可視化熱測試系統量測均溫板熱阻以及拍攝內部照片。 研究結果顯示，水的臨界瓦數為 7W，最低熱阻為 3.146(°C/W)；正丁醇方面以 6%的濃度效果最好，臨界瓦數為 11W，最低熱阻為2.441(°C/W)；正戊醇方面以 3%的濃度效果最好，臨界瓦數為 9W，最低熱阻為 2.596(°C/W)；正己醇方面臨界瓦數為 7W，最低熱阻為 2.49(°C/W)。從以上結果可知，二元混合流 體相較於水，臨界瓦數皆有顯著提升，熱阻也比水來的低。其中，又以 6%正丁醇的效果最好，臨界瓦數比水增加了 57%，對於薄型熱板來說有最佳的熱傳表現。

Today’s electronic products continue to evolve toward thinness and versatility. The development makes the product’s internal CPU generate more high heat. According to research, 55% of the damage of electronic products comes from the internal high temperature, the following are man-made and wet damage. It seen that heat dissipation plays an indispensable role in the development of technology. However, in pursuit of product thinning,the fluid quality must be decreased. The fluid quality is too less to load higher wattages. Therefore, the purpose of this experiment is using the Marangoni effect of the binary mixed fluids to enhance the flow from the condenser zone to the evaporator zone, delaying the occurrence of dry-out and increasing the critical heat transfer. In order to observe the internal dry-out phenomenon of the vapor chamber, we set up a visualized device, which can clearly observe the internal phase change and dry-out through the PC plastic upper cover. In terms of experimental fluids, we use pure water, 1-Butanol, 1-Pentanol and 1-Hexanol. In terms of concentration, the maximum solubility of each alcohol is selected. The concentration of 1-Butanol is ranging from 2~ The concentration of 1-Pentanol is ranging from 1~ The concentration of 1-Hexanol is only used in 0.6%. Changing the aboved fluids and concentration, and using the visualized heat device to measure the thermal resistance and take the internal photos. The results show that the critical wattage of pure water is 7W and the lowest thermal resistance is 3.146(°C/ For 1-Butanol, the 6% butanol aqueous solution has the best effect, the critical wattage is 11W and the lowest thermal resistance is 2.441(°C/ For 1-Pentanol, the 3% pentanol aqueous solution has the best effect, the critical wattage is 9W and the lowest thermal resistance is 2.596(°C/ For 1-Hexanol, the critical wattage is 7W and the lowest thermal resistance is 2.49(° C/W). From the aboved results,compared with pure water, the binary mixed working fluid has a significant increase in the critical wattage and has lower thermal resistance. Among binary mixed fluids, the 6% butanol aqueous solution has the best effect, the critical wattage is increased by 57% than pure water. Therefore, the 6% butanol aqueous solution is most effective on thin vapor chamber.