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系統識別號 U0026-2201201011061300
論文名稱(中文) 具渦流產生器之矩形鰭片鰭管式熱交換器之三維熱液動性能分析
論文名稱(英文) 3-D Thermal-Hydraulic Analysis for Rectangular finned-tube heat exchangers with vortex generators
校院名稱 成功大學
系所名稱(中) 機械工程學系專班
系所名稱(英) Department of Mechanical Engineering (on the job class)
學年度 98
學期 1
出版年 99
研究生(中文) 李大興
研究生(英文) Da-Sing Li
學號 N1795106
學位類別 碩士
語文別 中文
論文頁數 81頁
口試委員 指導教授-張錦裕
口試委員-黃正弘
口試委員-林建南
口試委員-呂金生
中文關鍵字 渦流產生器  熱交換器  計算流體力學 
英文關鍵字 vortex generators  heat exchangers  CFD-RC 
學科別分類
中文摘要 近年來,渦流產生器(Vortex generaror)常是被考慮為被動式熱傳增強技術的一種,它是利用一些小型凸出物,以浮花壓製(emboss)、黏附(stamp)、衝孔(punch)…等加工方式結合於主要的熱交換表面上(如: 鰭片),主要是避免邊界層產生分離及降低摩擦力;其優點除了具有上述所言之一般鰭片的熱增強特性外,亦有較小的壓降;本研究係於具圓型管矩形鰭片之熱交換器,以對齊式( in-line )排列與交錯式(staggered)排列之鰭管式熱交換器為區分,於其鰭片上裝設渦流產生器,區分為VG0~VG3等形式,其中,VG0是不具渦流產生器的最初形式,而VG1~VG3分別是展開30°、45°、60°擴散排列之波浪型渦流產生器,並以計算流體力學軟體模擬真實的使用狀況來分析整體的流場及熱液動效率;結果發現,在熱傳因子j(Colburn factor)方面,對齊式(in-lined)排列之矩形鰭管式熱交換器的熱增強現象中,VG2(45°)較VG1(30°)上升了18%,VG3(60°)較VG2(45°)上升了13%,而VG1(30°)則較無裝設者上升了38%,而在交錯式(staggered)排列之矩形鰭管式熱交換器中,VG2(45°)較VG1(30°)上升了20%,VG3(60°)較VG2(45°)上升了27%,而VG1(30°)則較無裝設者上升了26%;相對而言,摩擦因子f(friction factor)部分,相較於無裝設渦流產生器者,較無裝設者之對齊式VG1(30°)約增加24.6%,VG2(45°)增加至35.7%,VG3(60°)則增加至48.6%,增加最多,而交錯式的VG1(30°)則約增加26.3%,VG2(45°)則增加至40.3%,VG3(60°)則增加至53.3%,在面積縮減率(1-A/Aplain )的部分,對齊式中的VG3(60°)最佳(26.8%縮減至20.2%),而交錯式的則是VG2(45°)最佳(29.3%縮減至25.1%)。
英文摘要 Numerical analyses were carried out to study the 3-D heat transfer and flow in the rectangular finned-tube heat exchangers with inclined block shape vortex generators mounted behind the tubes. The study was performed for a variety of span angle over a range of flow conditions. In addition, numerical simulation was performed by a 3-D turbulence analysis of the heat transfer and fluid flow. There were four model types for this research, including VG0 to VG3. VG0 was the initial type which without vortex generators, and VG1 to VG3 represented the span angle 30°, 45° and 60°. The numerical result indicated these effects were intensified as the span angle is increased. Furthermore, no matter the arrangement type (in-lined and staggered), the case of 60° span angle provided the best heat transfer and Colburn factor augmentation, of course, the pressure drop and friction factor higher than the other, In Colburn factor, the 60° span angle case (VG3) is higher than without vortex generator 53.1% at in-line, staggered is higher 56.8%; In friction factor, the 60° span angle case (VG3) is higher than without vortex generator 48.6% at in-line, staggered is higher 53.3%. A reduction in fin area of 26.8% may be obtained if vortex generators embedded fins are used at in-lined arrangement rectangular finned-tube heat exchangers, and staggered arrangement reduction in fin area is 29.3% ~25.1%
論文目次 中文摘要 I
英文摘要 II
誌謝 III
目錄 IV
圖目錄 VI
符號說明 XI
第一章 緒論 1
第二章 理論分析 13
2.1 物理模型規格 13
2.2流場統御方程式 13
2.3牆函數 16
2.4 邊界條件 17
2.4-1進口邊界條件 17
2.4-2出口邊界條件 17
2.4-3週期性邊界條件 18
2.4-4固體表面邊界條件 18
2.4-5固體-液體交界處邊界條件 18
2.4-6紐塞數、阻力係數、Colburn因子計算 19
第三章 數值方法 28
3.1 建立格點 28
3.2 格點模型與格點測試 29
3.3統禦方程式之差分方程式的建立 29
3.4收斂條件 31
第四章 結果與討論 36
4.1板鰭式與矩形鰭片式之熱傳效率比較 36
4.2矩形鰭片式之各渦流產生器展開角度熱傳效率比較 37
第五章 結論 73
參考文獻 76
自述 81
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