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研究生:張桓銘
研究生(外文):Huan-Ming Chang
論文名稱:雙螺旋殼圈式熱交換器之性能模擬分析
論文名稱(外文):Simulation of Shell and Double Helical Coiled Heat Exchanger
指導教授:簡良翰簡良翰引用關係
指導教授(外文):Liang-Han Chien
口試委員:洪國書楊安石
口試委員(外文):Kuo-Shu HungAn-Shik Yang
口試日期:2012-07-17
學位類別:碩士
校院名稱:國立臺北科技大學
系所名稱:能源與冷凍空調工程系碩士班
學門:工程學門
學類:其他工程學類
論文種類:學術論文
論文出版年:2012
畢業學年度:100
語文別:中文
論文頁數:74
中文關鍵詞:計算流體力學螺旋管殼圈式熱交換器
外文關鍵詞:Computational Fluid DynamicsHelical tubesShell and Coil Heat Exchanger
相關次數:
  • 被引用被引用:4
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  • 下載下載:16
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本研究分析雙螺旋殼圈式水對水熱交換器之熱傳現象,並利用水為工作流體,固定入口溫度,再經由改變壁面溫度(296~321K)、入口流速(0.5~5 m/s)、曲率直徑(96mm、142mm)和間距(21、31.08mm),以計算殼圈式熱交換器之螺旋管管內熱傳與壓損。利用固定管側溫度與入口流量,改變殼側入口溫度(323~333 K)與流速(2~4 m/s),探討殼側熱傳性能。並參考文獻中各種參數範圍之壓損與熱傳經驗公式,而求得本研究之壓損與熱傳經驗公式。結果指出在有限的體積下,殼側與管側流量分別為1.18、0.95 kg/s與入口溫度分別為288、333 K的條件下,比較單、雙螺旋管之差異,雙螺旋管雖然在增加其熱交換面積的同時會造成熱傳係數的下降,但是卻能有效提升整體熱交換率,而且並不會造成殼側壓損的增加,且螺旋管內壓損會因為兩根螺旋管而平均分配,可使殼圈式熱交換器壽命延長,並減少維修費用。螺旋管管內壓損會因為曲率直徑的大小而變,當曲率直徑越小時,螺旋管內壓損會越大;流速越大時,壓損也會越大。本研究並分別提出螺旋管內摩擦係數經驗公式,及管內與殼側熱傳經驗公式。

In the present study, numerical investigation of mixed convection and pressure drop in a shell and double helical coiled heat exchanger is reported. Water is the working fluid and inlet temperature is fixed at 288K. Changing wall temperature (296~321K), inlet velocity (0.5~5 m/s), coil diameter (96mm, 142mm), and coil pitch (21, 31.08mm) to determined heat transfer and pressure drop inside helical tubes. In addition, shell side heat transfer and overall heat transfer coefficient are investigated with various shell side inlet temperature and velocity and fixed tube side inlet temperature and flow rate. For fixed shell side and tube side mass flow rate of 1.18, 0.95, respectively, fixed inlet temperature at 288, 333 K, respectively. Single and double helical tubes are compared. The results of the present numerical study indicate that double helical tubes yields lager greater heat exchange rate as a result of larger heat transfer surface area, although it also results in a smaller heat transfer coefficient. The tube side pressure drop is significantly decreased as a result of the split of liquid flow, while only minor influence of shell side pressure drop is found. The helical tube pressure drop increases with decreasing curvature radius, and increasing fluid velocity. This study was asked the empirical formula of the coefficient of friction within the coil, and the tube and shell side heat transfer empirical formula. Based on the results of numerical simulation for various parameters, empirical correlations of pressure drop and heat transfer of both tube side and shell side of a shell and double coil heat exchanger are proposed.

摘 要 ii
ABSTRACT iii
誌謝 iv
表目錄 vii
圖目錄 viii
第一章 緒論 1
1.1研究背景 1
1.2研究動機與目的 1
第二章 文獻回顧 5
2.1殼圈式熱交換器數值分析 5
2.2螺旋管之管內與管外對流熱傳 9
2.3螺旋管之管內壓損 14
2.4殼圈式熱交換器之ε-NTU關係式 16
2.5物性設定 17
第三章 數值方法 19
3.1基本假設 19
3.2統禦方程式 19
3.3 Realizable k-ε模型 22
3.4研究方法 22
3.5物理模型及邊界條件 24
3.5.1 螺旋管之管內熱傳與壓損模擬 24
3.5.2 殼圈式熱交換器熱傳與壓損模擬模型 25
3.6鬆弛因子與收斂條件設定 28
3.7格點獨立性分析 30
第四章 結果與討論 35
4.1模擬與文獻實驗模型驗證 35
4.2 螺旋管內壓損 40
4.2.1 入口流速之影響 40
4.2.2 螺旋管內壓損經驗公式 42
4.3螺旋管內對流熱傳 43
4.3.1壁面溫度之影響 43
4.3.2螺旋管內對流熱傳經驗公式 49
4.4管外對流熱傳 50
4.4.1殼側入口速度之影響 51
4.4.2殼側入口溫度之影響 57
4.4.3殼側對流熱傳經驗公式 57
4.5單螺旋與雙螺旋殼圈式熱交換器之差異 58
第五章 結論與未來展望 60
5.1結論 60
5.2建議與未來展望 60
參考文獻 62
符號彙編 65
附錄A 數值模擬方法 67


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