臺灣博碩士論文加值系統

台灣電廠鍋爐機組經常受限於附近陡峭坡地，而造成煙道彎管曲折，造成在煙道氣流經煙道靜電集塵器之前後發生煙氣流速不均勻及排放煙氣通過煙道彎管後，廢氣溫度降低程度不同，因而部份管壁因溫差大造成水份與廢氣中灰份反應凝結在壁面上，造成靜電集塵器效率降低和管壁腐蝕現象。本文主要目的在從等溫流場模型實驗，配合數值模擬分析作煙道彎管偏流現象探討之研究。將導流片組裝置於煙道彎管轉彎處，改變導流片參數以尋求最佳改善煙道彎管流場偏流現象。
研究結果顯示在未加入導流片之煙道彎管於彎曲段後產生偏流現象。改善煙道彎管內偏流現象的發生，可在彎管轉彎處加裝導流片組，增加彎曲段下游區流場均勻度。針對彎管轉彎處導流片的配置方面，以導流片尾部延伸直線段及不等間隔排列方式對於彎管截面法向速度上的流場均勻度改善效率最佳。在彎管截面水平切線與鉛直切線方向速度的均勻度上，以延長導流片尾部直線段與小幅度的改變導流片入流角度有正面的評價。

Many power plants in Taiwan due to the constraints of the geometric location, the distribution of the flow and temperature entering electrostatic precipitator is not uniform. It results in that the performance of EP is low, due to the unbalance of dust collection in both sides of the EP. Besides, the corrosion problem caused by the condensation of the water vapor in the system may occur. In this research, methods to improve the flow and temperature distribution in the flue gas duct between the boiler and the EP are investigated. The experimental scale-down isothermal flow model was fabricated, measured and numerical simulation was employed to investigate the non-uniform distribution of the flow phenomena. The object of this thesis is to place the guided vanes in the curved duct. Change the vane parameters to find out the optimum condition, which improve the non-uniform distribution of the flow best.
The results show that the non-uniform distribution of the flow will be appeared without the guided vanes in the curved duct and place the guided vanes will be improved. A reduced number of guided vanes, extending the length of the trailing edge of the guided vanes and rotating the angle of guided vanes with small extent will be beneficial for the non-uniform distribution of the flow.

第一章 緒論……………………………………………………………1
1-1 研究緣由與目的…………………………………………….1
1-2 研究方法簡述……………………………………………….1
第二章 文獻回顧………………………………………………………4
2-1 等溫流場模型之相似性理論………………….……………4
2-2 導流片對彎管流場的影響………………………………...11
第三章 實驗儀器與操作……………………………………………..18
3-1 實驗儀器…………………………………………………...18
3-1.1 速度量測儀器………………………………………..18
3-1.2 壓電轉換器…………………………………………..19
3-1.3 鼓風機………………………………………………..19
3-1.4 三軸電腦自動定位平移台…………………………..20
3-1.5 電腦資料擷取系統…………………………………..20
3-2 五孔皮托管的構造與操作方法…………………………...20
3-2.1 五孔皮托管的構造…………………………………..20
3-2.2 五孔皮托管之操作方法……………………………..23
3-3 相似性原理探討…………………………………………...24
3-3.1 幾何相似性之探討…………………………………..24
3-3.2 動力相似性之探討…………………………………..25
3-4 煙道彎管模型之建立……………………………………...25
3-5 操作條件…………………………………………………...26
3-5.1 煙道彎管模型入口流速之探討……………………..26
3-5.2 誤差測試……………………………………………..27
3-5.3 量測區域與量測點之選擇…………………………..28
第四章 理論模式……………………………………………………..31
4-1 流場基本假設…………………………………………….31
4-2 紊流模式………………………………………………….32
4-3 統御方程式……………………………………………….34
4-4 邊界條件的處理………………………………………….36
4-5 牆函數…………………………………………………….38
第五章 數值分析……………………………………………………..42
5-1數值方法…………………………………………………..42
5-1.1 差分方程式的處理…………………………………42
5-1.2 SIMPLE method……………………………………..44
5-2 PHOENICS流力數值計算商業軟體簡介………………..47
5-3 格點系統………………………………………………….49
5-4 鬆弛係數與收斂標準…………………………………….49
5-5 格點獨立測試…………………………………………….52
5-6 CFX流力數值計算商業軟體簡介………………………..53
5-7 流場均勻度之量化評估準則……………………….……54
5-7.1 流量偏流比、動量偏流比……………………………55
5-7.2 平均速度偏流角……………………………………..55
5-7.3 偏向動能比…………………………………………..56
第六章 結果與討論…………………………………………………..57
6-1 未加入導流片之流場變化………………………….……..58
6-1.1 實驗量測結果………………………………………..58
6-1.2 數值模擬結果………………………………………..59
6-2 加入導流片之流場變化…………………………………...61
6-2.1 加入導流片上下支撐物對流場的影響………….….62
6-2.2 實驗量測結果………………………………………..63
6-2.3 數值模擬結果………………………………………..64
6-2.4 導流片對煙道彎管流場的影響……………………..65
6-3 改變導流片參數於煙道彎管出口實驗量測之流場變化...65
6-3.1導流片數影響之探討…………………………………66
6-3.2 導流片尾部延伸影響之探討………………………..68
6-3.3 導流片入流角度影響之探討………………………..69
6-3.4 導流片不等間隔排列影響之探討…………………..70
6-4 實驗量測、數值模擬與導流片參數之比較與評估………72
6-4.1 截面法向速度分佈曲線之分析探討………………..72
6-4.2 物理量比例之分析探討……………………………..73
6-4.3 平均速度偏流角之分析探討………………………..74
6-4.4 偏向動能比之分析探討……………………………..75
6-5 數值計算可靠性評估……………………………………...76
第七章 結論…………………………………………………………..80

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