[[alternative]]Development of heat pipe heat exchanger

碩士[[abstract]]在現今能源短缺的危機中，能源如何節省與再利用是當前必須重視的課題，其中的廢熱排放是一大污染源之一。然而，在工業上使用的傳統熱交換器中，經常遭受廢氣排放的腐蝕與沉積物，造成熱回收效率降低和設備受損。熱管能有效率地將熱量從一端傳輸至另一端，並且無須外力驅動傳熱，而熱管熱交換器是熱管實際應用的方法之一，透過蒸發潛熱發揮長距離傳熱與小溫差的特性。 本研究提出氣對液熱管熱交換器之製造與測試，並探討熱管熱交換器的熱回收能力與熱性能表現。實驗裝置共裝設19支不鏽鋼-水熱管，規格為外徑6.2 mm、壁厚0.5 mm、長300 mm，於蒸發端流經入口溫度150-250 ºC與質量流率0.114-0.270 kg/min之熱氣體，冷凝端則流經恆定入口溫度30 ºC與質量流率0.940 kg/min之冷卻水，實驗結果顯示最大傳熱量為445.5 W，最大有效度為0.609。本文同時參考文獻中的理論相關性，進行實驗分析與理論研究探討。[[abstract]]In today''s energy shortage crisis, how to save energy and reuse is a must pay attention subject, and waste heat emissions is one of the major sources of pollution. However, conventional heat exchangers used in industry often suffer corrosion and sediment from exhaust gases, leading to a reduction in heat recovery efficiency and equipment failure. Heat pipes can effectively transfer heat from one end to another, without additional force to drive heat transfer. Heat pipe heat exchanger is one of the practical applications of heat pipe, through the latent heat of vaporization to transfer heat over a long distance and small temperature difference characteristics. In this study, the gas-to-liquid heat pipe heat exchanger was fabricated and tested, and the thermal recovery capability and thermal performance of heat pipe heat exchangers were investigated. The device consist 19 stainless steel-water heat pipes with an outside diameter of 6.2 mm, a wall thickness of 0.5 mm and a length of 300 mm. The experiment was conducted at conditions for which hot gas and cooling waters enter at temperatures of 150-250 ºC and 30 ºC, respectively. The flow rate of gas through the evaporator is at the range of 0.114-0.270 kg/min, while the flow rate of water through the condenser is 0.940 kg/min. The results showed that the maximum heat transfer rate was 445.5 W, and the maximum effectiveness was 0.609. The present research was also carried out the comparison between experimental and theoretical investigation with reference to the correlation in the literature.[[tableofcontents]]中文摘要........................................................................................................................ I 英文摘要....................................................................................................................... II 目錄.............................................................................................................................. IV 圖目錄........................................................................................................................ VII 表目錄....................................................................................................................... VIII 符號說明...................................................................................................................... IX 第一章 緒論.................................................................................................................. 1 1.1 研究背景與動機 ........................................................................................... 1 1.2 文獻回顧 ....................................................................................................... 4 1.2.1 氣對氣熱管熱交換器 ...................................................................... 4 1.2.2 液對液熱管熱交換器 ...................................................................... 9 1.2.3 氣對液熱管熱交換器 .................................................................... 11 1.3 研究目的 ..................................................................................................... 16 第二章 理論基礎........................................................................................................ 17 2.1 熱管介紹 ..................................................................................................... 17 2.1.1 熱管構造與工作原理 .................................................................... 17 2.1.2 虹吸式熱管 .................................................................................... 17 2.1.3 工作流體與作動溫度 .................................................................... 20 2.1.4 性能評估 ........................................................................................ 26 2.2 一般熱交換器介紹 ..................................................................................... 22 2.3 熱管熱交換器介紹 ..................................................................................... 22 2.3.1 熱管熱交換器之特性 .................................................................... 25 2.3.2 熱交換器性能評估 ........................................................................ 26 第三章 實驗製程與方法............................................................................................ 32 3.1 熱管熱交換器備製 ..................................................................................... 32 3.1.1 熱管規格 ........................................................................................ 32 3.1.2 熱管熱交換器規格 ........................................................................ 34 3.2 測試平台之架設 ......................................................................................... 35 3.2.1 操作平台 ........................................................................................ 35 3.2.2 實驗設備 ........................................................................................ 36 3.3 實驗步驟與參數 ......................................................................................... 39 3.4 實驗誤差分析 ............................................................................................. 41 第四章 實驗結果與討論............................................................................................ 42 4.1 冷熱流體之溫度變化 ................................................................................. 42 4.2 熱性能分析 ................................................................................................. 45 4.2.1 傳熱量 ............................................................................................ 45 4.2.2 有效度 ............................................................................................ 45 4.3 理論值與實驗值之比較與探討 ................................................................. 48 第五章 結論與建議.................................................................................................... 52 5.1 結論 ............................................................................................................. 52 5.2 未來建議 ..................................................................................................... 53 參考文獻...................................................................................................................... 54 附錄A 熱管熱交換器之實驗數據總表 .................................................................... 58 圖目錄 圖 1.1 台灣個別能源消耗量分布.............................................................................. 3 圖1.2 台灣產業不同溫度範圍之廢熱排放比例...................................................... 3 圖1.3 公車廢氣熱回收熱管熱交換器...................................................................... 5 圖1.4 空氣對空氣熱虹吸管熱交換器測試平台示意圖.......................................... 6 圖1.5 當冷凝端空氣流速為3 m/s 時， 不同蒸發端空氣流速下的整體有效度變化................................................ 6 圖1.6 空調系統熱回收熱管熱交換器...................................................................... 7 圖1.7 熱管佈置與熱氣體入口溫度對傳熱量的影響.............................................. 7 圖1.8 裝設旋轉架的熱虹吸管熱交換器.................................................................. 8 圖1.9 氣對氣熱虹吸管熱交換器.............................................................................. 9 圖1.10 液對液熱管熱交換器實驗裝置示意圖........................................................ 10 圖1.11 在冷卻水流率恆定的情況下，隨著熱廢水流率增加， 有效度與可用能效率的變化...................................................................... 10 圖1.12 熱含量比的變化對有效度與傳熱量的影響................................................ 11 圖1.13 熱空氣入口溫度對有效度與傳熱量的影響................................................ 11 圖1.14 氣對液熱虹吸管熱交換器冷凝端部分之橫截面(單位mm) ...................... 12 圖1.15 根據不同的風扇頻率與溫度下，熱交換器的有效度變化........................ 12 圖1.16 傳熱量與質量流率及入口溫度的關係........................................................ 13 圖1.17 理論預測值與實驗值間的比較.................................................................... 13 圖1.18 多殼側流道熱管熱交換器實驗裝置示意圖................................................ 14 圖1.19 實驗、理論與CFD 間的比較 ...................................................................... 15 圖1.20 有效度隨不同熱空氣入口溫度與質量流率的變化.................................... 15 圖2.1 熱管作動示意圖............................................................................................ 19 圖2.2 虹吸式熱管作動示意圖................................................................................ 19 圖2.3 板式熱交換器................................................................................................ 22 圖2.4 殼管式熱交換器............................................................................................ 23 圖2.5 套管式熱交換器............................................................................................ 23 圖2.6 有隔熱層的熱管熱交換器............................................................................ 24 圖2.7 無隔熱層的熱管熱交換器............................................................................ 24 圖2.8 燃燒爐應用熱管作預熱空氣的熱回收........................................................ 25 圖2.9 液體耦合間接傳導式熱交換器示意圖........................................................ 30 圖2.10 管束的排列(a)順向、(b)交叉 ...................................................................... 30 圖3.1 不鏽鋼-水熱管 .............................................................................................. 33 圖3.2 熱管熱交換器示意圖(單位:mm).................................................................. 34 圖3.3 熱管排列分布示意圖(單位:mm).................................................................. 34 圖3.4 測試平台示意圖............................................................................................ 35 圖3.5 熱風機............................................................................................................ 36 圖3.6 鼓風機............................................................................................................ 36 圖3.7 風速計............................................................................................................ 37 圖3.8 溫度量測模組................................................................................................ 37 圖3.9 恆溫水槽........................................................................................................ 38 圖3.10 流量計............................................................................................................ 38 圖4.1 熱氣體質量流率為0.270 kg/min 時，流體溫度隨時間的變化 ................ 43 圖4.2 熱氣體質量流率為0.192 kg/min 時，流體溫度隨時間的變化 ................ 43 圖4.3 熱氣體質量流率為0.114 kg/min 時，流體溫度隨時間的變化 ................ 43 圖4.4 熱氣體入口溫度分別在150 - 250 ºC 時，流體溫度分佈隨質量流率的變化 (固定Tc,in = 30 ºC 及 = 0.940 kg/min) ..................................................... 44 圖4.5 熱氣體質量流率對傳熱量的影響(固定Tc,in = 30 ºC 及 = 0.940 kg/min) .......................................................................................................................... 46 圖4.6 熱氣體放熱量與冷卻水吸熱量之間的關係................................................ 46 圖4.7 熱氣體質量流率對有效度的影響(固定Tc,in = 30 ºC 及 = 0.940 kg/min) .......................................................................................................................... 47 圖4.8 有效度的不確定性分析................................................................................ 47 圖4.9 實驗有效度與理論有效度的比較................................................................ 49 圖4.10 熱管熱交換器的ε-NTU 關係圖(NTUc = 0.8, n = 5) ................................... 49 表目錄 表 1.1 一般熱交換器與熱管熱交換器之比較.......................................................... 2 表1.2 公車廢氣熱回收實驗結果.............................................................................. 5 表2.1 主要工作流體與可作動溫度範圍................................................................ 20 表2.2 交互流方程式的常數.................................................................................... 31 表2.3 交互流方程式的修正因子(NL < 20) ............................................................ 31 表2.4 單圓管交互流方程式的常數........................................................................ 31 表3.1 水的物理性質................................................................................................ 33 表3.2 不鏽鋼316L 之性質 ..................................................................................... 33 表3.3 實驗參數........................................................................................................ 40 表4.1 實驗與理論比較之ε-NTU 關係圖繪製參數表 .......................................... 50 表4.2 冷凝端NTUc 計算過程表( = 0.940 kg/min) ........................................... 50 表4.3 蒸發端NTUe 計算過程表( = 0.270 kg/min) ........................................... 50 表4.4 蒸發端NTUe 計算過程表( = 0.192 kg/min) ........................................... 51 表4.5 蒸發端NTUe 計算過程表( = 0.114 kg/min) ........................................... 51 表4.6 ε-NTU 關係圖繪製參數表(NTUc = 0.8, n = 5) ............................................ 51 表A.1 熱氣體 = 0.270 kg/min 之實驗數據 ....................................................... 58 表A.2 熱氣體 = 0.192 kg/min 之實驗數據 ....................................................... 58 表A.3 熱氣體 = 0.114 kg/min 之實驗數據 ....................................................... 58[[note]]學號: 604350248, 學年度: 10