[[alternative]]Effect of nanofluids on loop thermosyphon thermal performance

碩士[[abstract]]本研究為探討奈米流體於迴路式虹吸熱管之熱性能影響。奈米流體為平均粒徑30nm銀奈米顆粒混合於水溶液中。 虹吸熱管蒸發室之尺寸為內徑25mm、高25mm；並於內部製作兩種的沸騰結構來研究其影響。第一種為平滑的沸騰表面，第二種為長寬17mm×17mm、厚度1mm、粒徑大小183.5μm、孔隙率53.7%的銅粉燒結結構。實驗元件為使用恆溫水槽進行冷卻，並固定流量與溫度20度之條件來進行實驗。實驗將以量測迴路式虹吸熱管之溫度分佈與溫差，來比較奈米流體與純水充填於迴路式虹吸熱管之性能。 實驗結果顯示使用平滑的沸騰表面時，在260W的輸入功率，濃度30ppm銀奈米流體的整體效能比純水提昇13.82%。當使用增強沸騰結構時，濃度20ppm銀奈米流體的整體體效能比純水提昇0.12%。[[abstract]]The purpose of this thesis is to study the effects of silver nano-fluids on loop thermosyphon thermal performance. The nano-fluid used in this study is an aqueous solution 30nm diameter silver nanoparticles. The evaporator chambers of thermosyphon used in this study has an inside diameter of 25 mm and a height of 25 mm. Two types of boiling structures in evaporator chambers have fabricated to investigate the influence. The first type of boiling structures is flat with smooth boiling surface. The second one is 17.3mm square, 1mm thickness of sintered copper powder structure. The average diameter of copper powder and the porosity is 185.5μm and 53.7%, respectively. The tested device was condensed by the thermal bath with constant flow rate at 20℃. The experiment was performed to measure the temperature distribution and the temperature difference to compare the thermal performance of nano-fluid and DI-water. Based on the smooth boiling surface of evaporator chambers, the experimental result of 30ppm silver nanofluid showed that thermal resistance enhanced 13.82% compared to DI-water at an input power of 260W. While the loop thermosyphon were with copper powder structure in the evaporator chamber, the thermal performance improved 0.12% at 20ppm silver nanofluid compare with DI-water.[[tableofcontents]]目錄 第一章 緒論..............................................................................................1 1-1 研究動機......................................................................................1 1-2 文獻回顧......................................................................................2 1-2-1 奈米流體應用於虹吸熱管..........................................2 1-2-2 奈米流體應用於熱管...................................................4 1-2-3 奈米流體應用於震盪式熱管.....................................9 1-3 研究目的....................................................................................12 第二章 理論基礎....................................................................................13 2-1 虹吸熱管簡介............................................................................13 2-1-1 虹吸熱管形式.............................................................14 2-1-2 虹吸熱管之優點.........................................................16 2-2 奈米流體簡介............................................................................16 2-2-1 奈米顆粒之製備.........................................................17 2-2-2 奈米流體之製備.........................................................18 2-3 沸騰理論介紹............................................................................20 2-3-1 沸騰的基本模式.........................................................20 2-3-2 成核理論.....................................................................21 2-3-3 池核沸騰的相關參數影響.........................................23 第三章 實驗設備與方法........................................................................25 3-1 迴路式虹吸熱管結構........................................................25 3-2 測試項目…………....................................................................28 3-3 實驗流程....................................................................................29 3-3-1 設備架設.....................................................................30 3-3-2 熱電偶線位置及校正.................................................31 3-3-3 加熱底板清潔.............................................................32 3-3-4 內部管路清潔.............................................................33 3-3-5 工作流體的準備.........................................................33 3-3-6 脫氣充填.......................................................................34 3-3-7 性能測試.....................................................................36 3-3-8 加熱平台構造與原理...................................................36 第四章 實驗結果與討論................................................................38 4-1 純水與銀奈米流體比較 - 平板結構…..................................39 4-1-1 加熱表面......................................................................39 4-1-2 蒸發端溫差..................................................................40 4-1-3 整體溫差……………………………………………..41 4-2 純水與銀奈米流體比較 - 銅粉燒結結構.............................42 4-2-1 加熱表面……………………………………………..42 4-2-2 蒸發端溫差…………………………………………..43 4-2-3 整體溫差……………………………………………..44 4-3 分析與探討…………………………………………………...45 4-3-1 銀奈米流體於不同加熱表面之沸騰性能影響……..45 4-3-2 蒸發端性能比較…………………………..…............51 4-3-3 銀奈米流體整體效能提升比……..............................52 第五章 總結與建議………………………………………………...….58 5-1 總結……………………………………………………….......58 5-2 未來建議………………………………………………….......60 參考文獻..................................................................................................61 附錄一 性能測試實驗數據....................................................................64 附錄二 充填量誤差值............................................................................79 附錄三 不準度分析.............................................................................80 圖目錄 圖1-1 虹吸熱管充填奈米流體與純水之整體熱阻比較......................2 圖1-2 虹吸熱管充填奈米流體與純水之熱傳性能比較......................3 圖1-3 虹吸熱管充填奈米流體與純水之整體熱阻比較......................3 圖1-4 虹吸熱管充填奈米流體與去離子水之熱阻比較......................4 圖1-5 金奈米流體與純水之性能比較..................................................5 圖1-6 去離子水與銀奈米流體之熱管效能比較..................................6 圖1-7 純水於光滑表面與微溝槽表面之沸騰熱傳性能比較..............6 圖1-8 氧化銅奈米流體於光滑表面與微溝槽之沸騰熱傳性能比較..7 圖1-9 氧化銅奈米流體與純水之整體熱阻性能比較......................8 圖1-10 氧化銅奈米流體在不同系統壓力之熱傳係數提升比..............8 圖1-11 氧化銅奈米流體在不同系統壓力的臨界熱通量提升比..........8 圖1-12 銀奈米流體在相同濃度不同粒徑與純水的溫差......................9 圖1-13 鑽石奈米流體與去離子水之震盪式熱管溫差比較................10 圖1-14 鑽石奈米流體與去離子水之震盪式熱管熱阻比較................10 圖1-15 銅奈米流體與高純度蒸餾水之熱傳性能比較........................11 圖1-16 不同填充率與奈米流體體積比之熱傳性能比較....................11 圖2-1 虹吸熱管作動示意圖................................................................13 圖2-2 單管虹吸熱管............................................................................14 圖2-3 迴路式平行熱虹吸熱管............................................................15 圖2-4 迴路式虹吸熱管........................................................................15 圖2-5 常見奈米粉末製作方法............................................................18 圖2-6 基本沸騰模式............................................................................20 圖2-7 過熱表面成核過程....................................................................21 圖2-8 池沸騰區域加熱表面的蒸汽結構............................................22 圖2-9 各種不同增強沸騰表面............................................................24 圖3-1 迴路式虹吸熱管 爆炸圖..........................................................26 圖3-2 平板結構加熱底板....................................................................27 圖3-3 銅粉燒結結構加熱底板............................................................27 圖3-4 迴路式虹吸熱管 尺寸圖..........................................................27 圖3-5 迴路式虹吸熱管 組合完成圖..................................................28 圖3-6 實驗流程圖................................................................................29 圖3-7 測試設備示意圖........................................................................30 圖3-8 熱電偶線位置............................................................................31 圖3-9 加熱器平台構造........................................................................37 圖4-1 銀奈米流體與純水之加熱表面溫度比較平板結構..............39 圖4-2 銀奈米流體與純水之蒸發端溫差比較平板結構..................40 圖4-3 銀奈米流體與純水之整體溫差比較平板結構......................41 圖4-4 銀奈米流體與純水之加熱表面溫度比較銅粉燒結結構......42 圖4-5 銀奈米流體與純水之蒸發端溫差比較銅粉燒結結構..........43 圖4-6 銀奈米流體與純水之整體溫差比較銅粉燒結結構..............44 圖4-7 純水於平板結構之沸騰與液膜關係圖....................................46 圖4-8 銀奈米流體於平板結構之沸騰與液膜關係圖........................47 圖4-9 純水於銅粉燒結結構之沸騰關係圖...............................47 圖4-10 銀奈米流體於銅粉燒結結構之沸騰關係圖...................47 圖4-11 銅粉燒結結構之SEM圖(500倍)..............................................48 圖4-12 銀奈米顆粒於銅粉燒結結構之SEM圖(500倍)…………......48 圖4-13 銅粉燒結結構之SEM圖(1000倍)……....................................49 圖4-14 銀奈米顆粒於銅粉燒結結構之SEM 圖(1000倍).................49 圖4-15 銅粉燒結結構之SEM 圖(2000倍) ........................................50 圖4-16 銀奈米顆粒於銅粉燒結結構之SEM 圖(2000倍) ................50 圖4-17 濃度20ppm銀奈米流體與純水之蒸發端溫差比較................51 圖4-18 銀奈米流體於蒸發端效能提升比較平板結構………............53 圖4-19 銀奈米流體於冷凝端效能提升比較平板結構……................53 圖4-20 銀奈米流體於整體效能提升比較平板結構………................54 圖4-21 銀奈米流體於蒸發端效能提升比較銅粉燒結結構……........55 圖4-22 銀奈米流體於冷凝端效能提升比較銅粉燒結結構……........55 圖4-23 銀奈米流體於整體效能提升比較銅粉燒結結構..................56 圖4-24 銀奈米流體與純水於不同沸騰結構之整體效能提升比較....57 表目錄 表4-1 實驗操作參數............................................................................38[[note]]學號: 695370337, 學年度: 9