本研究利用ANSYS Fluent針對高功率60W LED散熱鰭片模組進行熱流場分析，將原本的輻射狀散熱鰭片更改為螺旋狀鰭片，比較兩者在自然對流及強制對流下之散熱性能，並探討螺旋狀鰭片之曲率半徑與鰭片數量對散熱模組整體溫度之影響。
結果顯示在自然對流下，螺旋狀模組之散熱性能僅略高於輻射狀模組，但是有風扇之螺旋氣流吹向散熱模組時，螺旋狀模組之散熱性能明顯優於輻射狀模組。隨著螺旋狀模組之鰭片曲率半徑增加，散熱器及PCB溫度亦隨之上升，代表熱量無法散去而逐漸累積。鰭片散熱性能亦會因鰭片數之增加而提升，但是在鰭片數量超過30片後，繼續增加鰭片數反而會使散熱性能下降。另外，圓形散熱鰭片無論鰭片曲率半徑或數量多寡，大部份熱量皆累積於散熱器中央處
，其原因為相較於鰭片外圍，鰭片中央處與空氣接觸之面積較小，因此鰭片表面與空氣進行熱交換之效能較差，且受到回流的影響，大部分流經鰭片中央處之氣流皆為已受熱之空氣，導致熱量更容易堆積於鰭片中央處。

This research investigated the temperature and flow fields of LED light bulbs by a CFD software (ANSYS-FLUENT). A 60W LED is used as the reference model for comparison. Some modified models with spiral fins were studied under free and forced convections. Various radiuses of curvature and numbers of fins were also studied and analyzed for heat dissipation performance. 
Results demonstrated that when cooled by the spiral airflow cooling module was the heat dissipation performance of the spiral module was obviously better than the radial module. While under natural convection, the cooling performance of the spiral module was only slightly better than that of radial module. For spiral module, as the curvature of fins increased, temperature of cooling model and PCB were both increased. 
The increased numbers of fins, which regulated the radius of curvature, increased the heat dissipation performance. However, when the number of fins greater than 30, the fins would be highly packed and would cause the cooling performance decreased. In addition, in both spiral and straight modules, most of the heat was accumulated in the central regions.

目錄	I
圖目錄	III
表目錄	VII
符號表	VIII
第 1 章 緒論	1
1.1 前言 1
1.2 研究動機 3
1.3 文獻回顧 4
第 2 章 基礎理論 13
2.1 發光二極體原理 13
2.2  LED熱傳途徑 15
2.2.1 熱傳導 15
2.2.2 熱對流 17
2.3 熱阻定義 18
第 3 章 研究方法 20
3.1 幾何建構 20
3.1.1 散熱模組 20
3.1.2 熱流場計算域 20
3.2 網格建立 21
3.2.1 網格生成方法 21
3.2.2 網格質量分析 22
3.3 邊界條件 22
3.4 統御方程式 23
3.5  BOUSSINESQ近似法 25
3.6 數值方法 26
3.6.1 軟體介紹 26
3.6.2 演算法設定 27
第 4 章 結果與討論 30
4.1 模擬結果與參考文獻之比較 30
4.2 網格獨立性分析 30
4.3 螺旋狀散熱模組鳍片之曲率半徑分析 31
4.4 螺旋狀散熱模組之鳍片數分析 34
4.5 自然對流下輻射狀與螺旋狀散熱模組分析 36
第 5 章 結論與未來展望 37
5.1 結論 37
5.2 未來展望 39
參考文獻 40

圖目錄
圖1- 1 紅光二極體[1] 49
圖1- 2 計算結果與實驗值比較圖[28] 49
圖1- 3 LM type 與LMS type示意圖[29] 50
圖1- 4 In-line pin fin與Staggered pin fin示意圖[30] 51
圖2- 1 波爾原子模型[41] 52
圖2- 2 PN二極體基本結構[42] 52
圖2- 3 空乏區[43] 53
圖2- 4 順向偏壓示意圖[43] 53
圖2- 5 非平滑接觸表面與溫度分布圖[47] 54
圖3- 1 B6030U-80MXNA 60W LED散熱鰭片實體圖 54
圖3- 2 原始輻射狀模組之物理模型軸側圖 55
圖3- 3 輻射狀模組之物理模型俯視圖 55
圖3- 4 輻射狀模組之物理模型側視圖 56
圖3- 5 輻射狀模組之物理模型軸側圖 56
圖3- 6 螺旋狀模組物理模型俯視圖 57
圖3- 7 螺旋狀模組物理模型側視圖 57
圖3- 8 螺旋狀模組物理模型軸側圖 58
圖3- 9 自然對流之計算域側視圖 58
圖3- 10 散熱器內加裝風扇示意圖 59
圖3- 11 強制對流之計算域側視圖 59
圖3- 12 輻射狀散熱模組網格 60
圖3- 13 螺旋狀散熱模組網格 60
圖3- 14 計算域網格(a)自然對流 (b)強制對流 61
圖3- 15 散熱模組與空氣交界處之網格剖面圖 61
圖3- 16 偏斜率分布直條圖(a)輻射狀(b)螺旋狀 62
圖3- 17 正交程度值分布直條圖(a)輻射狀(b)螺旋狀 63
圖3- 18 自然對流邊界條件示意圖 64
圖3- 19 強制對流邊界條件示意圖 65
圖4- 1 物理模型與計算域俯視圖 66
圖4- 2 物理模型與計算域側視圖 66
圖4- 3 圓形散熱模組 (n=20) 67
圖4- 4 n=20之溫度分布圖: (a)側視圖 (b)俯視圖(H=10mm) 68
圖4- 5 溫度分布對照圖: (a)Yu et al.[28] (b)本研究(H=10mm) 69
圖4- 6 輻射狀與螺旋狀模組之網格獨立性分析 70
圖4- 7 (a)xy (b)xz (c)yz平面 71
圖4- 8 曲率半徑13mm溫度分布圖：(a)xy (b)xz (c)yz平面 72
圖4- 9 曲率半徑23mm溫度分布圖：(a)xy (b)xz (c)yz平面 73
圖4- 10 曲率半徑33mm溫度分布圖：(a)xy (b)xz (c)yz平面 74
圖4- 11 輻射狀模組溫度分布圖：(a)xy (b)xz (c)yz平面 75
圖4- 12 曲率半徑13mm速度場：(a)xy (b)xz (c)yz平面 76
圖4- 13 曲率半徑23mm速度場：(a)xy (b)xz (c)yz平面 77
圖4- 14 曲率半徑33mm速度場：(a)xy (b)xz (c)yz平面 78
圖4- 15 輻射狀模組速度場：(a)xy (b)xz (c)yz平面 79
圖4- 16 輻射狀模組速度場(x=0mm) 80
圖4- 17 輻射狀模組速度場(x=2mm) 80
圖4- 18 輻射狀模組速度場(x=6mm) 81
圖4- 19 螺旋模組(曲率半徑23mm)速度場(x=0mm) 81
圖4- 20 螺旋模組(曲率半徑23mm)速度場(x=2mm) 82
圖4- 21 螺旋模組(曲率半徑23mm)速度場(x=6mm) 82
圖4- 22 曲率半徑13mm流線圖：(a)xy (b)xz (c)yz平面 83
圖4- 23 曲率半徑23mm流線圖：(a)xy (b)xz (c)yz平面 84
圖4- 24 曲率半徑33mm流線圖：(a)xy (b)xz (c)yz平面 85
圖4- 25 輻射狀模組流線圖 86
圖4- 26 不同曲率半徑下之PCB和散熱器平均溫度 87
圖4- 27 不同曲率半徑下之熱對流係數 87
圖4- 28 xy平面溫度分布圖：(a)n=20 (b)n=25 (c)n=30 (d)n=36 88
圖4- 29 鰭片表面溫度分布：(a)n=20 (b)n=25 (c)n=30 (d)n=36 89
圖4- 30 n=20速度場：(a)xy (b)xz (c)yz平面 90
圖4- 31 n=25速度場：(a)xy (b)xz (c)yz平面 91
圖4- 32 n=36速度場：(a)xy (b)xz (c)yz平面 92
圖4- 33 n=20流線圖：(a)xy (b)xz (c)yz平面 93
圖4- 34 n=25流線圖：(a)xy (b)xz (c)yz平面 94
圖4- 35 n=36流線圖：(a)xy (b)xz (c)yz平面 95
圖4- 36 不同鰭片數之PCB和散熱器平均溫度 96
圖4- 37 不同鰭片數之熱對流係數 96
圖4- 38 自然對流下輻射狀模組溫度分布圖：(a)xy (b)xz (c)yz平面 97
圖4- 39 自然對流下螺旋模組溫度分布圖：(a)xy (b)xz (c)yz平面 98
圖4- 40 自然對流下散熱器表面溫度分布圖：(a)輻射 (b)螺旋 99
圖4- 41 自然對流下輻射狀模組速度場：(a)xy (b)xz (c)yz平面 100
圖4- 42 自然對流下螺旋狀模組速度場：(a)xy (b)xz (c)yz平面 101

表目錄
表2- 1 常見光源散熱途徑比例表[34] 102
表3- 1 材料性質表 102
表3- 2 各項離散化演算法則設定 102
表4- 1 輻射與螺旋狀模組網格數與PCB平均溫度 103
表4- 2 不同曲率半徑下之螺旋散熱模組表面積與溫度數據 103
表4- 3 螺旋狀模組在不同鰭片數之表面積與溫度數據 103
表4- 4 強制對流下輻射與螺旋狀模組之散熱效能 104
表4- 5 自然對流下輻射與螺旋狀模組之散熱效能 104

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