[[alternative]]Fabrication and visualization of a loop thermosyphon

碩士[[abstract]]本文為研製與測試可視化之迴路式虹吸熱管，其蒸發器內部為直徑35mm、長19mm，汽相流道外徑9mm、液相流道外徑6mm，管壁厚度各為1.5mm，冷凝器管路內直徑6mm、長81mm，加熱面積為31mm x 31mm。 迴路式虹吸熱管於內部壓力7 Torr(mmHg)下充填20%之去離子水，銅粉燒結毛細結構之直徑為35mm並製作成三種不同之厚度分別為0.4mm、0.7mm、1.0mm，銅粉平均粒徑與孔隙率分別為100μm及51%。輸入功率逐步由18W增加至236W，分別量測加熱表面溫度及汽相流道入口溫度以進行虹吸熱管的性能評估，並透過玻璃視窗拍攝記錄蒸發器內部毛細結構之汽泡生成與成長現象，包含蒸發器內部底面起始核沸騰、毛細結構起始核沸騰與穩態核沸騰及燒乾時汽泡生成的情形。 實驗結果顯示，起始核沸騰於加熱表面溫度43.3℃時發生；毛細結構表面之工作流體於56.7℃開始核沸騰，穩態核沸騰始於59.0℃；當輸入功率超過236W，則產生燒乾現象。當毛細結構厚度為1.0mm，輸入功率為235W時，加熱表面溫度為83.5℃，具有最低熱阻值為0.07℃/W，此時毛細結構表面為薄膜沸騰模式。[[abstract]]The purpose of this paper is to fabricate and study visualization of a loop thermosyphon. The size of the device are as the follow; the inner diameter of the cylindrical evaporator is 35mm with a length of 19mm; the inner diameter of the vapor flow passage and the liquid flow passage are 9mm and 6mm respectively, the thickness of tube-wall is 1.5mm; the inner diameter of condenser passage is 6mm and with a length of 81mm, and the heating area is 31mm x 31mm. DI water with 20% filling ratio was charged into the thermosyphon at a pressure of 7 Torr. Copper sinter wick structure with diameter of 35mm was fabricated with three different thicknesses of 0.4mm, 0.7mm and 1.0mm. The average diameter of copper powder and the porosity is 100μm and 51%, respectively. Heating surface temperature and inlet temperature at vapor flow passage were measured to evaluate performance of the thermosyphon when the heating input power is from 18W to 236W. Visualization of the loop thermosyphon is based on glass window. During video recording, we found that different power inputs causes variable bubble growth, including initial nucleate boiling of evaporator, initial nucleate boiling of wick structure, steady state boiling, and dried out. The experimental results show that the initial nucleate boiling occurred when the heating surface temperature was 43.3℃. When the temperature reached 56.7℃, the wick structure started initial nucleate boiling, and the steady state boiling status occurred at temperature of 59.0℃. Finally, the system dried out while power input is above 236W. The result show the loop thermosyphon with 1.0mm sinter thickness and 235W had a better performance with the lowest thermal resistance of 0.07℃/W, and the heating surface temperature was 83.5℃. We also found the phenomenon of thin film boiling was occurring in the same time.[[tableofcontents]]目錄 中文摘要..................................................................................................... I 英文摘要....................................................................................................II 目錄.......................................................................................................... IV 圖目錄.....................................................................................................VII 表目錄....................................................................................................... X 符號說明.................................................................................................. XI 第一章 緒論............................................................................................... 1 1.1 研究背景......................................................................................................... 1 1.2 文獻回顧.......................................................................................................... 2 1.2.1 迴路式虹吸熱管與效能分析............................................................... 2 1.2.2 作動分析與觀察................................................................................... 5 1.3 研究目的....................................................................................................... 12 第二章 理論簡介..................................................................................... 13 2.1 虹吸熱管(Thermosyphon) ............................................................................. 13 2.2 虹吸熱管類型................................................................................................ 14 2.2.1 單管式（Single Tube Thermosyphon）............................................. 14 2.2.2 迴路式平行熱虹吸熱管（Loop Parallel Thermosyphon） .............. 14 2.2.3 迴路式虹吸熱管（Loop Thermosyphon） ....................................... 15 2.2.4 迴路式虹吸熱管之優點..................................................................... 15 V 2.3 沸騰理論....................................................................................................... 16 2.3.1 沸騰基本模式..................................................................................... 16 2.3.2 臨界熱通量(Critical Heat Flux, CHF)................................................ 17 2.3.3 成核理論............................................................................................. 18 2.4 池核沸騰(Nucleate Pool Boiling)的相關參數影響..................................... 18 2.4.1 表面粗糙度......................................................................................... 20 2.4.2 表面沾溼性......................................................................................... 21 2.4.3 傾斜角................................................................................................. 21 第三章 實驗裝置製作與流程................................................................. 22 3.1 裝置製作....................................................................................................... 23 3.1.1 迴路式虹吸熱管設計與製作............................................................. 23 3.1.2 毛細結構之燒結與製作..................................................................... 26 3.2 清洗裝置....................................................................................................... 31 3.3 溫度感測配置............................................................................................... 31 3.3.1 焊接與校正.......................................................................................... 31 3.3.2 配置與熱阻計算................................................................................. 32 3.4 充填工作流體................................................................................................ 32 3.4.1 充填量制訂.......................................................................................... 34 3.4.2 工作流體脫氣..................................................................................... 34 3.4.3 充填步驟.............................................................................................. 34 VI 3.5 實驗測試....................................................................................................... 36 第四章 實驗結果與分析......................................................................... 41 4.1 毛細結構厚度性能分析............................................................................... 41 4.1.1 溫度比較............................................................................................. 43 4.1.2 熱阻比較............................................................................................. 44 4.2 迴路式虹吸熱管沸騰過程........................................................................... 44 4.2.1 燒乾時沸騰情形................................................................................. 44 4.2.2 沸騰起始情形..................................................................................... 46 4.2.3 燒結結構沸騰起始情形..................................................................... 47 4.2.4 穩態時沸騰情形................................................................................. 47 4.3 迴路式虹吸熱管性能與汽泡關係............................................................... 48 第五章 總結與建議................................................................................. 51 5.1 總結............................................................................................................... 51 5.1.1 蒸汽汽泡生成現象............................................................................. 51 5.1.2 效能與汽泡關係................................................................................. 52 5.2 未來建議....................................................................................................... 52 參考文獻.................................................................................................. 54 附錄1 實驗數據...................................................................................... 56 附錄2 沸騰情形...................................................................................... 58 附錄3 誤差分析...................................................................................... 63 VII 圖目錄 圖1.1 直立式環形封閉虹吸熱管示意圖..........................................................................................3 圖1.2 二相流迴路式虹吸熱管設計圖..............................................................................................4 圖1.3 二相流迴路式虹吸熱管效能圖..............................................................................................4 圖1.4 毛細燒結結構示意圖..............................................................................................................5 圖1.5 加熱功率100W 時不同表面之蒸發熱阻..............................................................................5 圖1.6 彎曲式虹吸熱管設計圖..........................................................................................................6 圖1.7 彎曲式虹吸熱管於蒸發與冷凝作動情形..............................................................................6 圖1.8 汽泡生成於銅線表面..............................................................................................................7 圖1.9 熱傳機制過程之液面變化......................................................................................................7 圖1.10 管路內溫度分布....................................................................................................................8 圖1.11 不同厚度於各種測試下之比較圖........................................................................................8 圖1.12 無電鍍層與有電鍍層於不同熱通量之觀察........................................................................9 圖1.13 有無多孔隙表面之性能圖....................................................................................................9 圖1.14 CFD 虹吸式熱管蒸發時程圖..............................................................................................10 圖1.15 虹吸式熱管溫度分布圖......................................................................................................10 圖1.16 (a)高速攝影機與(b)紅外線熱像儀拍攝汽泡生成週期...................................................... 11 圖1.17 汽泡生成與熱傳相關機制概要圖...................................................................................... 11 圖2.1 虹吸熱管作動示意圖............................................................................................................13 圖2.2 單管虹吸熱管示意圖............................................................................................................14 圖2.3 迴路式平行熱虹吸熱管示意圖............................................................................................15 圖2.4 迴路式虹吸熱管示意圖........................................................................................................15 圖2.5 基本沸騰模式........................................................................................................................16 圖2.6 沸騰曲線................................................................................................................................17 圖2.7 成核過程................................................................................................................................18 圖2.8 池沸騰區域加熱表面的蒸汽結構........................................................................................19 圖2.9 各種不同增強沸騰表面........................................................................................................20 圖2.10 表面沾溼性..........................................................................................................................21 圖3.1 實驗流程圖............................................................................................................................22 圖3.2 迴路式虹吸熱管作動圖........................................................................................................24 VIII 圖3.3 迴路式虹吸熱管尺寸圖........................................................................................................24 圖3.4 迴路式虹吸熱管構件圖........................................................................................................25 圖3.5 迴路式虹吸熱管完成圖........................................................................................................25 圖3.6 迴路式虹吸熱管圖................................................................................................................26 圖3.7 圓盤型石墨燒結治具............................................................................................................27 圖3.8 蒸發底板................................................................................................................................29 圖3.9 銅粉燒結試片........................................................................................................................29 圖3.10 MH-600P 電子比重計.........................................................................................................29 圖3.11 MHV-1 真空抽取機............................................................................................................30 圖3.12 銅粉燒結結構使用OM 放大200 倍.................................................................................30 圖3.13 銅粉燒結結構使用OM 放大500 倍.................................................................................30 圖3.14 熱電偶配置圖......................................................................................................................32 圖3.15 充填架設示意圖...................................................................................................................33 圖3.16 真空抽取機..........................................................................................................................35 圖3.17 數位壓力計..........................................................................................................................35 圖3.18 微量電子秤..........................................................................................................................36 圖3.19 實驗架設示意圖..................................................................................................................37 圖3.20 實驗設備架設圖..................................................................................................................37 圖3.21 Phantom v4.2 型高速攝影機...............................................................................................38 圖3.22 SPARTAN-L 數據擷取器 v1.03 型....................................................................................38 圖3.23 GPR-3010HD 電源供應器...................................................................................................38 圖3.24 YI-FENG P-20 恆溫水槽.....................................................................................................39 圖3.25 流量計.................................................................................................................................39 圖3.26 加熱平台結構圖..................................................................................................................40 圖4.1 不同輸入功率測定最佳充填率.............................................................................................41 圖4.2 燒結厚度0.4mm 效能圖......................................................................................................42 圖4.3 燒結厚度0.7mm 效能圖......................................................................................................42 圖4.4 燒結厚度1.0mm 效能圖......................................................................................................42 圖4.5 不同燒結厚度於穩態時實際輸入功率................................................................................43 圖4.6 不同燒結厚度於穩態時蒸發端溫度與輸入功率關係........................................................43 圖4.7 燒結厚度之蒸發端熱阻與輸入功率關係............................................................................44 IX 圖4.8 燒乾前之蒸發端沸騰情形....................................................................................................45 圖4.9 輸入功率17W 之蒸發端沸騰情形......................................................................................46 圖4.10 輸入功率86W 時之蒸發端沸騰情形................................................................................47 圖4.11 輸入功率91W 穩態時之蒸發端沸騰情形........................................................................48 圖4.12 燒結厚度1.0mm 時與沸騰情形關係圖............................................................................49 圖 附1.1 溫度校正圖......................................................................................................................56 圖 附1.2 燒結厚度0.4mm 數據圖................................................................................................56 圖 附1.3 燒結厚度0.7mm 數據圖.................................................................................................57 圖 附1.4 燒結厚度1.0mm 數據圖.................................................................................................57 圖 附2.1 輸入功率18W 之蒸發端沸騰情形................................................................................58 圖 附2.2 輸入功率86W 時之蒸發端沸騰情形............................................................................59 圖 附2.3 輸入功率91W 穩態時之蒸發端沸騰情形....................................................................60 圖 附2.4 燒乾前之蒸發端沸騰情形..............................................................................................62 X 表目錄 表1.1 流體與金屬材質配合表..........................................................................................................2 表1.2 蒸發端沸騰溫度與熱通量關係..............................................................................................2 表3.1 蒸發端毛細結構製作參數....................................................................................................27 表3.2 燒結識片特性數據表............................................................................................................28[[note]]學號: 697370293, 學年度: 9