臺灣博碩士論文加值系統

本文實驗利用環境風洞進行量測橫列式雙排放源排放氣懸性追蹤氣體在二維阻牆之氣體擴散變化情形，並分析探討阻牆在不同排放源下游位置、以及不同雙源間距等參數變化對風場與濃度場所造成之差異。
量測分析結果顯示(1)在阻牆上方會出現氣流加速現象，而在阻牆後方則受到阻牆阻擋使得風速降低以及呈現迴流現象。(2)在橫列式兩排放源間距為18倍煙囪直徑時，約在下游約3倍煙囪高度處雙源之濃度羽流發生交會混合現象。

The experiments were conducted in the wind tunnel to measure the dispersion characteristics of the two side by side sources located before fence，Effects of the location of fence, gap of two sources, and source hight on the wind flow and dispersion characteristics were investigated.
Experimental results show that:(1)The wind accelerated as it past the fence, then the wind speed decreased, due to blockage effect of the fence. Furthermore,the reverse flow appeared behind the fence.(2)When the gap of two sources was 18 times source diameter, two concentration plumes interacted and merged around at downstream distance of three times of source heights.

摘要 I
目錄 II
符號說明 X
第一章 導論 1
1.1　　研究動機 1
1.2 研究目的 2
1.3文獻回顧 2
第二章 風洞模擬擴散之理論與分析 4
2.1 中性大氣層紊流邊界層之風場特性 4
2.1.1 平均風速剖面 5
2.1.2 紊流強度 7
2.1.3雷諾應力 9
2.1.4紊流頻譜 11
2.2 大氣紊流邊界層之風洞模擬分析 11
2.3 高斯擴散理論 14
2.4 阻牆後方尾流區特性 15
2.5.1 阻牆後尾流區之物理變因 17
2.6 因次分析探討 19
第三章 實驗配置方法與設計 21
3.1 大氣環境風洞 21
3.1.1 整流段 21
3.1.2 收縮段 22
3.1.3 試驗段 22
3.1.4 動力段 22
3.2 迫近流場之條件模擬 22
3.2.1 迫近流場量測之設備 23
3.2.2 迫近流場之量測 26
3.3 濃度場量測與設備 26
3.3.1追蹤氣體排放系統 26
3.3.2 追蹤氣體採樣系統 27
3.4 實驗設計及流程 28
3.4.1 實驗之流程 29
3.4.2 模型縮尺之設計與放置 29
3.4.3 實驗物理條件之設計 30
3.4.4 實驗之採樣點設計 32
第四章 實驗結果與討論 34
4.1 迫近流場 34
4.1.1 平均風速剖面 34
4.1.2 紊流強度剖面 35
4.1.3 雷諾應力 35
4.1.4 紊流速度頻譜 36
4.2 速度場特性 36
4.3 濃度場特性 38
4.3.1濃度分佈特性 39
4.3.2質心位置與擴散尺度分布特性 43
第五章 結論 44
參考文獻 46
附圖 50

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