臺灣博碩士論文加值系統

摘要
由於奈米流體結合噴霧冷卻法能再提升噴霧冷卻法之熱傳效率，近年來使用奈米流體結合噴霧冷卻法之實驗已經被大量的進行探討與研究。因此本實驗以奈米流體結合噴霧冷卻法，對熱表面進行多次實驗，並進行熱傳效率及其表面變化之探討。實驗首先使用二階法製備二種體積分率的三氧化二鋁-水奈米流體(0.001Vol%、0.05Vol%)，分別對熱表面(Cu)進行長時間之奈米流體結合噴霧冷卻法之實驗，結果顯示，三氧化二鋁-水奈米流體在體積分率0.001Vol%時，其熱傳效率並不會因實驗次數增加而降低熱傳效率，其表面潤濕性變化不大；而三氧化二鋁-水奈米流體體積分率在0.05Vol%時，因為其沉澱量較多、較快，使得奈米吸附層(Sorption layer)厚度增加，增加熱表面之熱阻，使得熱傳效率不斷下降，即使表面潤濕性有明顯變化，也無法提升熱傳效率。

Abstract
As combination of nanofluid with spray cooling can further enhance heat transfer efficiency, experiments integrating the two have been extensively discussed and investigated in recent years. Therefore, this paper makes a research on heat transfer efficiency and hot surface changes by combining nanofluid with spray cooling and conducting repeated experiments of hot surface. Firstly, it uses second-order method to prepare two kinds of Al2O3-water nanofluids with two different volume fractions (0.001Vol%, 0.05 Vol %), and implements more than three times of nanofluid-and-spray-cooling integrated experiments for hot surface (Cu). Results show: when volume fraction of Al2O3-water nanofluid is 0.001Vol%, heat transfer efficiency doesn’t decrease as the number of times of experiments increases and superficial wettability doesn’t change significantly. Under a volume fraction of 0.05Vol%, large quantity of sediments and rapid speed of sedimentation cause increases in thickness of nano adsorption layer and thermal resistance of hot surface and thus make heat transfer efficiency continuously decline; even an evident change in superficial wettability won’t enhance heat transfer efficiency.

目次
誌謝 I
摘要 II
Abstract III
目次 IV
表目錄 VII
圖目錄 VII
第一章緒論 1
1.1研究動機與目的 1
1.2研究方法 2
1.3論文架構 3
第二章文獻回顧 4
第三章基本原理與理論分析 7
3.1池沸騰熱傳機制 7
3.2噴霧冷卻法熱傳機制 7
3.3臨界熱通量 9
3.4潤濕性的探討 10
第四章奈米流體製備與介紹 13
4.1奈米流體的優點 13
4.2奈米粉末的製備 14
4.3奈米分末的種類 15
4.4奈米流體的製備 16
4.5奈米流體增強熱傳的機制 17
第五章實驗設備與方法 20
5.1噴霧冷卻系統 20
5.1.1主迴路 20
5.1.2測試段 22
5.1.3加熱模組 23
5.1.4量測元件 27
5.1.5預熱系統 27
5.1.6工作流體之輸送系統 27
5.1.7恆溫系統 28
5.1.8資料擷取系統 28
5.2表面形態分析儀器 29
5.2.1場發射槍穿透式電子顯微鏡(FEG-TEM) 29
5.2.2掃描式電子顯微鏡(Scanning Electron Microscope) 29
5.2.3研磨拋光機 29
5.2.4白光干涉儀(White Light Interferometers) 30
5.3奈米流體製備之相關儀器 30
5.3.1微量天秤 30
5.3.2磁石攪拌機 31
5.3.3超音波震盪器 32
5.3.4超音波破碎機 32
5.3.5熱傳導率量測儀 33
5.3.6接觸角量測儀 33
5.4實驗步驟與方法 34
5.4.1實驗進行前系統設備清洗與準備步驟 34
5.4.2實驗樣本檢測與調配 34
5.4.3加熱表面粗糙度製作與量測 36
5.4.4噴霧冷卻實驗步驟 37
5.4.5噴霧沸騰實驗測試表面溫度計算 39
5.4.6不準確性分析 40
第六章實驗結果與分析 43
6.1實驗參數之驗證 43
6.1.1熱傳導率量測結果與分析 40
6.1.2噴霧冷卻實驗結果驗證 40
6.2實驗之結果與分析 46
6.2.1奈米流體於不同體積分率對噴霧冷卻熱傳之影響 40
6.2.2噴擊次數對實驗之影響 40
6.3表面型態與成分分析(SEM&EDS) 49
6.4加熱試片表面接觸角量測 55
第七章結論與建議 59
7.1結論 59
7.2建議 60
參考文獻 61
符號彙整 65

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