臺灣博碩士論文加值系統

摘要
本文主要是要以熱力學第二定律---熵產生(Entropy generation)的觀點並結合局部(平均)紐塞數和摩擦係數的數值計算，去探討不可壓縮層流流體，流經具有交錯、對稱排列、貼壁式加熱凸塊或是非貼壁式加熱凸塊之渠道，其流場、壁面熱傳和其摩擦係數的影響。而其統御方程式乃是以有限體積法(Finite Volume Method)為基礎，配合有限元素法(Finite Element Method)。至於格點設計方面，在本文中則採用非交錯網格(no-stagger grid or collocation)的系統去解Navier-Stokes方程式。
並針對下列的參數作探討：(1)入口雷諾數(Re)，(2)凸塊高度與渠道高度比(H/2B)，(3)交錯排列時凸塊與凸塊的交錯間距比(S/H)，(4)非貼壁排列時，凸塊與壁面的間隙比(C/H)。探討其對流場與熱傳所造成的影響。而工作介質則採用空氣。
在渠道中加裝凸塊，主要乃是在改變渠道之流場型態，並藉由增加熱傳面積，使流體與壁面有更激烈之交互作用進而去增加熱傳效率，但是相對於此效應，流場之摩擦損失通常亦會增加，所以要如何在減少摩擦損失及增加熱傳之間達成平衡，使其有最佳效率是我們探討的重點。
至於加熱流場，則分別是在凸塊表面保持固定壁溫，進行預測其熱傳係數的分佈狀況與物理現象。

Abstract
This study main employ “Second Law of Thermodynamics (Entropy generation)“viewpoint and Local (Average) Nusselt number to analysis the effects of incompressible laminar channel flow fluid, wall heat transfer characteristics and friction coefficient with Wall-Attached and Wall-Detached Heated Blocks and staggered or in-line blocks.
The governing equations are solved by a Finite-volume-based Finite-Element method .In this study, no-stagger grid or collocation are used to solve the Navier-Stokes equations.
The parameters interested include (1) entrance Reynolds number (Re), (2) the ratio of block height to channel height (H/2B), (3) the distance between two blocks staggered (S/H), (4) the ratio of interval (blocks detached from wall) to channel height (C/H).
Moreover, the enhancement in heat transfer is accompanied with increase in the friction loss to fluid flow. The reduce friction loss and increase heat transfer reach balance. We suppose to discuss the optimum efficient.
For a heated flow field, a constant heated wall temperature is considered along blocks. The distributions of heat transfer coefficient and the physical phenomena of this flow field are presented.

目錄
摘要I
AbstractII
誌謝III
目錄IV
表目錄VII
圖目錄IX
符號說明XVI
第一章、緒論1
1-1 研究動機及背景1
1-2 文獻回顧4
1-3 研究方法與目的6
1-4 本文架構7
第二章 理論分析13
2-1 基本假設13
2-2 統御方程式14
2-3 無因次化分析15
2-4 理論依據與公式推導16
2-4-1 熵產生(Entropy generation)16
2-4-2 摩擦係數(Friction coefficient)17
2-4-3 局部紐塞數(Local Nusselt number)18
2-4-4 平均紐塞數(Average Nusselt number)18
第三章 數值模擬21
3-1 數值方法21
3-1-1 統御方程式21
3-1-2 控制體積22
3-1-3 離散化24
3-1-4 壓力項與擴散項的處理25
3-1-5 數值通量的計算26
3-1-6 非交錯網格27
3-2 邊界條件28
第四章 結果與討論36
4-1 具對稱排列凸塊之渠道流分析36
4-1-1 貼壁式加熱凸塊，凸塊高度與渠道高度比(H/2B)之影響36
4-1-2 貼壁式加熱凸塊，凸塊寬度與凸塊高度比(W/H)之影響39
4-1-3 非貼壁加熱凸塊，凸塊間隙與凸塊高度比(C/H)之影響41
4-1-4 全非貼壁式加熱凸塊，凸塊間隙與凸塊高度比(C/H)之影響45
4-2 具交錯排列凸塊之渠道流分析47
4-2-1 非貼壁式加熱凸塊，交錯間距與凸塊高度比(S/H)之影響47
第五章 結論與建議90
5-1 結論90
5-2 建議93
參考文獻94
自述99
著作權聲明99

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