平板式熱管之研製與可視化觀察

Fabrication and Visualization of a Flat Plate Heat Pipe

吳宗謙(Tzong-Chian Wu)

指導教授 ： 康尚文

淡江大學/工學院/機械與機電工程學系碩士班/碩士(2010年)

https://doi.org/10.6846/TKU.2010.00897

摘要

本研究主要是設計並製造出可視化之平板式熱管，搭配去離子水做為工作流體，採用燒結厚度0.4mm、0.7mm與1.0mm的燒結銅粉做為熱管之毛細結構。平板式熱管在輸入功率20W、40W及60W之情況下，撘配不同的燒結厚度與一系列的填充率進行測試。實驗透過高速攝影機進行可視化觀察熱管內部熱傳機制對性能之影響，量測熱管各點溫度與計算蒸發熱阻，且有系統地檢測分析沸騰與蒸發時的條件參數對於熱管熱性能之影響程度。
實驗的結果顯示輸入熱源、毛細燒結厚度與充填量，皆會影響熱源溫度與蒸發熱阻值等性能。燒結厚度0.4mm之毛細結構在輸入功率為60W時，有較佳的蒸發熱阻0.119℃/W。透過可視化觀察，發現液面會隨著熱通量增加而下降，在蒸發端之流體燒乾前，蒸發熱阻隨熱通量增加而逐漸降低至一最小值，且熱管內部之工作流體液面與毛細結構頂面的高低差，是影響蒸發端沸騰機制的主因。當液面高於毛細時，沸騰機制以池沸騰為主，且蒸發熱阻較高；當液面低於毛細時，伴隨著薄膜沸騰的發生會有較低的蒸發熱阻。

關鍵字

平板式熱管 ； 燒結銅粉 ； 池沸騰 ； 薄膜沸騰

並列摘要

This study aims to design and fabricate a visualization flat plat heat pipe, with 0.4mm, 0.7mm and 1.0mm thick sintered copper wick structure. Three different sintering thicknesses of wicks with a series of filling ratio of deionized water were tested at heat input of 20W, 40W and 60W. Through a high-speed camera, the experiment was conducted to observe the boiling phenomenon of the evaporator in heat pipe. Evaporation resistance was evaluated from the measured temperature to analyze the parameters impact on performance.
The experimental results showed that the flat plate heat pipe at the different heat input, with the different thicknesses of wicks and filling ratio, which would affect thermal performance of the module, such as temperature of heat source and evaporation resistance. At input power of 60W, the 0.4mm thick wick structure with 5% filling ratio has the lowest resistance of 0.119℃/W. Through visual observation, the liquid surface would descend when the heat flux increased, and the evaporation resistance could reach a minimum by increasing heat flux before drying out. We also found that the main reason for affecting the heat transfer mechanism is the height of working fluid inside the heat pipe. When the liquid surface is above the top of wicks, the mainly boiling mechanism is pool boiling with higher evaporation resistance, and a thin film boiling occurred with a lower resistance, when the surface is below the top of wicks.

並列關鍵字

Flat plate heat pipe ； sintered copper powder ； pool boiling ； thin film boiling

參考文獻

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