本研究利用計算流體力學軟體(Computational Fluid Dynamics，CFD)模擬氣體吸收的薄膜接觸器之吸收性能與吸收器內之特徵。因系統涉及氣液兩相，本研究採用FLUENT內之VOF(Volume of Fluid)多相模式(Multiphase model)。氣液介面間之熱質傳，利用使用者定義函數(udf，user defined function)方式，將薄膜內部之熱質傳效應納入氣液介面之能量與質量平衡關係，並求解介面溫度。本研究模擬範圍涵概層流與紊流。
透過模擬建立了吸收器內部之特性分佈，顯示氣相存在濃度極化現象；網格細化程度探討顯示並非最細化之網格所得吸收量為最低；模擬與實驗吸收量之比較顯示相對高低結果為一致，但模擬值均高於實驗值；操作條件之影響分析顯示改變液相流體流量對吸收量影響最大，顯示此系統主要受控於液相；與熱質傳係數關聯式之比較結果顯示，紊流較層流之偏離程度為小。

This thesis uses Computational Fluid Dynamics software, FLUENT, to simulation the characteristics inside the absorber, for the flat plate membrane contactors used as gas absorbers. Since it is a vapor-liquid two phase system, the VOF (Volume of Fluid) multiphase model is adopted.
The heat and mass transfer across vapor and liquid interface was calculated by solving the interface temperature as well as the corresponding phase equilibrium composition using User Defined Functions (UDF) in FLUENT. Both laminar and turbulent flow regimes are studied.
The profiles of state variables inside the absorber are obtained. The effects of grid size and the flow rates and temperatures of inlet streams are studied. The heat and mass transfer coefficients in terms of relations between dimensionless groups, Nu vs. Re and Sh vs. Re, are analyzed and compared to reported correlations in the literature. The reported correlations are not applicable to the membrane absorbers.

目錄
誌謝 i
中文摘要ii
英文摘要iii
目錄iv
圖目錄vii
表目錄x
第一章 前言1
第二章 文獻回顧3
第三章 計算流體力學模式建立	5
3.1 網格建立5
3.2 數學模式7
3.2.1 基本統制方程式7
3.2.2 多相模式7
3.2.3 紊流模式10
3.2.4 邊界條件12
3.2.5 離散方法15
3.3自訂函數16
3.4 迭代運算控制參數19
3.5 收斂準則20
第四章 層流系統之模擬分析21
4.1 網格影響22
4.1.1 網格設定22
4.1.2 吸收性能23
4.1.3 內部特性分佈之比較25
4.2 模擬與實驗結果之比較28
4.3 吸收器內部特性	31
4.3.1 氣液介面區31
4.3.2 氣相區36
4.3.3 液相區38
4.4 操作條件之影響	40
4.4.1 吸收量之比較	40
4.4.2 輸送係數之比較42
第五章 紊流系統之模擬結果50
5.1 吸收器內部特性	51
5.1.1 氣液介面區	51
5.1.2 氣相區56
5.1.3 液相區58
5.2 操作條件之影響	60
5.2.1 吸收量之比較	60
5.2.2 輸送係數之比較62
第六章 結論69
參考文獻72
符號說明74


      圖目錄
圖3.1 兩層吸收器之網格圖5
圖3.2 三層吸收器之網格圖6
圖3.3 各UDFs之功能18
圖4.1 介面處未加以細化之網格圖22
圖4.2 介面處加以細化之網格圖23
圖4.3 內部特性分佈截面或截線位置25
圖4.4 介面氣相層溫度– Line b (a)個案A-1 (b)個案A-2 26
圖4.5 氣液介面溫度– Line a (a)個案A-1 (b)個案A-2 26
圖4.6 介面液相層溫度– Line c (a)個案A-1 (b)個案A-2 27
圖4.7液相至氣相之氨成份通量(吸收量之負值，kg/s/m2)
-	Line a (a)個案A-1 (b)個案A-2 27
圖4.8液相至氣相之水成份通量(吸收量之負值，kg/s/m2)
- Line a (a)個案A-1 (b)個案A-2 27
圖4.9 三層模組 28
圖4.10 介面氣相層溫度分佈-Line b 32
圖4.11 氣液介面溫度分佈-Line a 32
圖4.12 介面液相層溫度分佈-Line c 32
圖4.13 液相至氣相之氨成份通量(吸收量之負值，kg/s/m2 33

圖4.14 液相至氣相之水成份通量(吸收量之負值，kg/s/m2)
– Line a 33
圖4.15 介面氣相層速度分佈-Plane b 34
圖4.16 介面氣相層溫度分佈- Plane b 34
圖4.17 介面氣相層氨組成分佈- Plane b 34
圖4.18 介面液相層速度分佈-Plane c 35
圖4.19 介面液相層溫度分佈- Plane c 35
圖4.20 介面液相層氨組成分佈- Plane c 35
圖4.21 氣相區截線速度分佈 37
圖4.22 氣相區截線溫度分佈 37
圖4.23 氣相區截線氨組成分佈 37
圖4.24 液相區截線速度分佈 39
圖4.25 液相區截線溫度分佈 39
圖4.26 液相區截線氨組成分佈 39
圖4.27 氣相質傳與熱傳係數分佈-Line b (個案D-1 44
圖4.28 液相質傳與熱傳係數分佈-Line b (個案D-1 45
圖4.29 Sh對Re關聯 46
圖4.30 Nu對Re關聯 48
圖5.1 介面氣相層溫度分佈-Line b 52
圖5.2 氣液介面溫度分佈-Line a 52
圖5.3 介面液相層溫度分佈-Line c 52
圖5.4 液相至氣相之氨成份通量(吸收量之負值，kg/s)-Line a 53
圖5.5 液相至氣相之水成份通量(吸收量之負值，kg/s)-Line a 53
圖5.6介面氣相層速度分佈-Plane b 54
圖5.7介面氣相層溫度分佈- Plane b 54
圖5.8介面氣相層氨組成分佈- Plane b 54
圖5.9 介面液相層速度分佈-Plane c 55
圖5.10 介面液相層溫度分佈- Plane c 55
圖5.11 介面液相層氨組成分佈- Plane c 55
圖5.12 氣相區截線速度分佈 57
圖5.13 氣相區截線溫度分佈 57
圖5.14 氣相區截線氨組成分佈 57
圖5.15 液相區截線速度分佈 59
圖5.16 液相區截線溫度分佈 59
圖5.17 液相區截線氨組成分佈 59
圖5.18 氣相質傳與熱傳係數分佈-Line b (個案E-1 63
圖5.19 液相質傳與熱傳係數分佈-Line b (個案E-1 64
圖5.20 Sh對Re關聯 65
圖5.21 Nu對Re關聯 67


         表目錄
表3.1 吸收器尺寸與網格設定 6
表3.2 邊界條件12
表3.3 使用之離散方法 15
表3.4 低鬆弛因子 19
表3.5 收斂準則 20
表4.1 個案彙整表 21
表4.2 薄膜吸收器之裝置尺寸 21
表4.3 不同網格細化個案之吸收量 24
表4.4 個案A與個案B之物流與吸收量資料 24
表4.5 三層模組裝置尺寸 29
表4.6 模擬與實驗值之比較 29
表4.7 個案C之物流與吸收量資料 30
表4.8 改變操作條件各個案之物流吸收量資料 41
表5.1 個案彙整表 50
表5.2 改變操作條件各個案之物流吸收量資料 61

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