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研究生:陳佩孚
研究生(外文):Chen Pei-Fu
論文名稱:三維多孔間隙隔板通道之紊流熱傳數值模擬分析
論文名稱(外文):Numerical Simulation of Turbulent Heat Transfer in a Three- Dimensional Channel with Porous Baffles
指導教授:莊書豪莊書豪引用關係
指導教授(外文):Chuang Shu-Hao
學位類別:碩士
校院名稱:國立中興大學
系所名稱:機械工程學系
學門:工程學門
學類:機械工程學類
論文種類:學術論文
論文出版年:2001
畢業學年度:89
語文別:中文
論文頁數:108
中文關鍵詞:三維多孔性介質熱交換器紊流
外文關鍵詞:three-dimensionalporous mediumheat exchanger
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本文利用計算流體力學PHOENICS軟體來模擬一紊流三維渠道內放置多個多孔性隔板流場。採用連續方程式和動量方程式,並配合SIMPLE-C法則與κ-ε雙方程式紊流模式,並以控制體積法建立有限差分方程式。多孔性隔板交插地放置在底部及頂部,並且改變各種物理參數,諸如雷諾數的大小(Re=10000~50000)、多孔隙隔板的孔隙度(0%、20%及42%)、多孔隙隔板的寬度比(w/W= 1/4、1/2、3/4及1)、多孔隙隔板的高度比(h/H= 0.25、0.5及0.75)等等,看看其對平均紐塞數及摩擦係數的影響。
本文結果顯示,當固定隔板高度和雷諾數下,多孔性介質隔板渠道較實心隔板渠道之整體平均紐塞數高出63%~73%。由此可知多孔隙介質隔板渠道的熱傳效果比實心隔板渠道來得好。且實心隔板渠道較多孔性介質隔板渠道的摩擦係數高出65%~81%。故多孔性介質隔板渠道所受到的流場阻力較實心隔板渠道來得小。本文研究結果除可以提供建立起多孔隙隔板在熱交換器內的最佳化設計外,更能對多孔隙介質應用有較深一層的瞭解。

In this study , a computational fluid (CFD) code , PHOENICS is used to calculate the three-dimensional nature of turbulent flow in a channel with porous baffles. Owing to the turbulent characteristic by the porous baffles flowfield, the continuity equation , momentum equation , and the k-ε turbulence model are adopted to construct the model with control volume integration for finite difference associated with SIMPLE-C algorithm .The porous baffles are arranged on the bottom and top channel walls in a staggered manner. And we will investigate the various parameters , such as Reynolds number(Re= 10000 to 50000) and the porosity of the baffle (0%,20% and 42%), respectively; the baffle broad ratio (w/W=1/4,1/2,3/4 and 1) and the baffle height ratio (h/H=0.25,0.5 and 0.75). The correlation for the average Nusselt number and friction factor are also developed in terms of flow and baffled parameters .
From the present result result , the average Nusselt number of a 3-D duct in the porous baffle is higher about 63~73% than the solid baffle when the baffle height and Reynolds number of flow field are fixed. And the friction factor of solid baffle is higher about 65~81% than the porous baffle. Consequently, the results of the investigation will provide a reference and fundamental optimize design for the porous baffle in the heat exchanger.

目錄
中文摘要Ⅰ
英文摘要Ⅱ
目錄Ⅲ
表目錄Ⅵ
圖目錄Ⅶ
符號說明XIV
第一章緒論 1
1.1 前言 1
1.2 文獻回顧 2
1.3 研究動機與目的 5
第二章物理模型與統御方程式6
2.1 物理模型 6
2.2 基本假設 7
2.3 統御方程式 8
2.4 壁函數 12
2.5 邊界條件 14
2.6 摩擦係數 17
2.7 局部紐塞數的計算 17
第三章數值方法與求解程序 19
3.1 簡介 19
3.2 網格點系統 19
3.3 格點獨立測試 20
3.4 差分方程式的建立 21
3.4.1數值分析 21
3.4.2差分方程式 21
3.4.3 混合法則 22
3.5 求解程序 25
3.5.1 SIMPLE求解法 25
3.5.2 SIMPLEST與SIMPLE求解法之比較28
3.5.3 收斂條件 29
3.5.4 數值模擬流程 30
第四章結果與討論 31
4.1 流場特性分析 32
4.1.1 流場之速度向量圖 32
4.1.2 雷諾數之改變對摩擦係數之影響33
4.1.3 隔板種類之改變對摩擦係數之影響 34
4.1.4 隔板高度之改變對摩擦係數之影響 35
4.2 熱傳特性分析 35
4.2.1雷諾數對紐塞數之影響 36
4.2.2不同種類隔板對紐塞數之影響 36
4.2.3 隔板的高度改變對紐塞數之影響36
4.3 2-D隔板與3-D隔板所產生流場性質比較 37
第五章結論與建議 39
5.1 結論 39
5.2 對未來研究方向之建議 40
參考文獻 41
附表 44
附圖 46

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