臺灣博碩士論文加值系統

近年來隨著電子產品務求微小美觀化，以微流道進行散熱應用於電子散熱越來越常見，然而若是以幫浦做為動力來源，長時間會有損壞之疑慮。本文使用兩相迴路型系統熱虹吸是以流體自身重力壓差驅動系統運作，無幫浦損壞疑慮更無需額外耗能。本文針對兩相熱虹吸迴路系統以壓降公式預測系統之質量流率以及工作流體流經各元件之壓損，目的在於預估系統能在不同與散熱量自我調整，發現在系統驅動力較大時系統能有較高之熱傳效率，驅動力較小時系統容易呈現不穩定狀態。
探討熱虹吸系統之蒸發器沸騰間隙對熱傳效能的影響，發現降低沸騰間隙會使得質量流率降低，工作流體能充分受熱，提升熱傳效率。

The two phase thermosyphon for electronics cooling which working capitalizes upon fluid density differences between two interconnected tubes, this study present a pressure drop model to predict mass flow rate and pressre drop components throughout the loop, this pressure drop model is based on mass, momentum, and energy balance, the heat flux and the condenser heights are the control variable. From the result, the more height exam has better heat transfer efficiency and this pumpless system can self-adapt with change the variable.
The microchnnel cooling is applied in the boiling gap, the gap was varied from 0.13 to 3.56 mm. The smaller gap has higher heat transfer efficiency with smaller mass flow rate.

摘要 ..................................................................................................................................... i
Abstract .................................................................................................................................. ii
誌謝 ...................................................................................................................................... iii
目錄 ...................................................................................................................................... iv
表目錄 ................................................................................................................................... v
圖目錄.............................................................................................................................. vi
符號說明 ............................................................................................................................. viii
第一章、緒論 ....................................................................................................................... 1
1.1 前言 ................................................................................................................... 1
1.2 文獻回顧 ........................................................................................................... 3
1.3 研究動機與目的 ............................................................................................... 7
1.3.1蒸發器之沸騰間隙高度變化熱傳研究 ................................................. 8
1.3.2兩相熱虹吸系統蒸發與冷凝端之高度差熱傳研究 ............................. 9
第二章、基本原理 ............................................................................................................. 16
2.1 沸騰模式 ......................................................................................................... 16
2.2 池沸騰 ............................................................................................................. 16
2.2.1 沸騰曲線 .............................................................................................. 16
2.3 對流沸騰 ......................................................................................................... 18
2.4汽泡成核與成長 .............................................................................................. 20
2.5 LTS之流動循環模型 ....................................................................................... 23
2.5.2 壓降模型 ...................................................................................................... 24
第三章、蒸發器之沸騰間隙高度變化熱傳研究 ........................................................... 28
3.1研究目的 .......................................................................................................... 28
3.2沸騰間隙實驗說明 .......................................................................................... 29
3.3模擬蒸發器改變沸騰間隙模型建構 .............................................................. 30
3.3.2邊界條件設定 ............................................................................................... 30
第四章、結果與討論 ......................................................................................................... 34
4.1沸騰間隙對氣泡生成、質量流率之影響 ...................................................... 34
4.2沸騰間隙對熱傳影響 ...................................................................................... 35
4.3高度變化對系統壓降之影響 .......................................................................... 52
第五章、結論與未來展望 ................................................................................................ 62
參考文獻......................................................................................................................... 63

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