臺灣博碩士論文加值系統

背向階梯結構簡單但現象多變，應用十分廣泛，而當加入壁面噴流後流場機制與混合行為更加複雜。本文藉由實驗方法，探討在背向階梯之分離流場中，壁面蒸散之流體對於流場行為以及冷卻機制之影響，透過定性之流場觀測以及定量之量測，進一步釐清了文獻中對於噴流所造成之流場模態結構與流場特性未解之處。另一方面，再透過蒸散壁面之噴流區域的控制，藉由薄膜模態之噴流質量流率比在不同噴流區域的選定下，研究整體流場之溫度表現與冷卻行為，並探討低溫噴流與高溫進口流之間的混合現象，進一步深入瞭解蒸散冷卻之機制與效應。
實驗中透過流場觀測，細察各流場模態間不同區域之流場特徵，再藉由速度場之量測瞭解流場速度分佈及紊流特性，並針對流場之壓力及擾動進行量測分析。在控制噴流範圍之條件中，進一步透過流場溫度以及壁面溫度之穩態及暫態量測，探討溫度分佈以及降溫程度，並進行熱傳係數之估算，以便瞭解流場及壁面之冷卻行為。
在四種流場模態之結構歸納中，透過局部之觀測歸納出四種流場模態更為完整之流場型態，可確實區分各流場模態之結構，並以速度量測結果作一對照與印證，發現四種模態之階梯角落、主迴流區、再接觸區、以及下游渦漩逸散之結構皆有其不同之表現。在局部噴流的條件中，分別針對0-7H、3.5-10.5H、7-14H之噴流位置的選定來進行分析，其中局部噴流0-7H所得之流場冷卻區域較為廣闊，然而下游區域之流場受到高溫主進口流之強烈混合與衝擊效果，因而表現出較高之紊流動能以及較差之低溫冷卻表現，而噴流區域之壁面由於擁有內機制之冷卻，因此擁有較佳之冷卻趨勢，顯示出蒸散冷卻對壁面之良好保護冷卻效果；另一方面，降溫係數之結果顯示，低溫區域與最大降溫幅度非重疊之區域，可做為不同應用之參考。在熱傳係數方面，透過壁面史丹頓數之計算，可判斷各條件下壁面熱傳分佈趨勢。除此之外，在局部噴流0-7H之條件下，於流場下游約27H位置加上一結構後，對於14H前方之流場整體的降溫效果與冷卻趨勢造成巨大之改善與突破，整體低溫區域大幅增加，特別值得重視。

摘 要
誌 謝
目 錄
圖表目錄
符號說明
第一章 前言
第二章 文獻回顧
2-1 基本背向階梯的流場與熱傳研究 ……………………..
2-2 壁面噴流對於流場之效應研究 ………………………..
2-3 具壁面噴流之背向階梯流場的熱傳研究 ……………..
2-4 背向階梯下游流場之相關研究 ………………………..
2-5 背向階梯流場之暫態分析 ……………………………..
第三章 實驗設計
3-1 實驗設備 ………………………………………………..
3-1-1 熱流風洞 …………………………………………..
3-1-2 供氣系統 …………………………………………..
3-1-3 測試區 ……………………………………………..
3-1-4 壁面噴流系統 ……………………………………..
3-1-5 流場觀測系統 ……………………………………..
3-1-6 溫度量測系統 ……………………………………..
3-1-7 壓力量測系統 ……………………………………..
3-1-8 兩軸精密定位系統 ………………………………..
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3-1-9 頻譜量測系統 ……………………………………..
3-1-10 速度量測系統 ……………………………………
3-2實驗方法及實驗參數 …………………………………..
3-2-1 含壁面噴流之流場行為與機制研究 ……………..
3-2-1.1流場觀測 ………………………………………
3-2-1.2 速度場量測 …………………………………...
3-2-1.3 壓力量測 ……………………………………...
3-2-1.4 頻譜量測 ……………………………………...
3-2-2 噴流範圍對於冷卻效果及熱傳行為之效應研究 ..
3-2-2.1流場觀測 ………………………………………
3-2-2.2 溫度場量測 …………………………………...
3-2-2.3 速度場量測 …………………………………...
3-2-2.4 暫態溫度場之量測 …………………………...
3-2-2.5 壓力場量測 …………………………………...
3-2-2.6 頻譜量測 ……………………………………...
3-2-3 流場二維性研判 …………………………………..
3-2-4 不準度分析 ………………………………………..
第四章 壁面蒸散之流場模態結構與特性分析
4-1 壁面蒸散之流場模態概略分類與說明 ………………
4-2 流場觀測與結構分析 …………………………………..
4-2-1 再接觸區及其下游之流場結構觀測 ……………..
4-2-2 階梯角落之流場結構觀測 ………………………..
4-3 各流場模態之速度量測與分析比較 …………………
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4-3-1 平均速度場 ………………………………………..
4-3-1.1 流場速度向量分佈 …………………………...
4-3-1.2 平均速度場之量值分析與比較 ……………...
4-3-2 流場紊流特性及分析 ……………………………..
4-4 各流場模態壓力分析與比較 …………………………
4-5 各模態完整流場之結構歸納 …………………………
4-6 頻譜分析 ………………………………………………
第五章 局部壁面噴流之流場結構與行為分析
5-1 局部噴流之流場結構觀測 ……………………………
5-2 速度量測結果與分析比較 ……………………………
5-2-1平均速度場 …………………………………………
5-2-2 流場紊流特性及分析 ……………………………..
5-3 局部壁面噴流之流場頻譜量測 ………………………
第六章 局部壁面噴流之穩態流場溫度表現與冷卻行為分析
6-1 流場及壁面穩態溫度表現 ……………………………
6-1-1 流場溫度分佈 ……………………………………..
6-1-2 壁面溫度分佈 ……………………………………..
6-1-3 流場溫度擾動量 …………………………………..
6-2 穩態壁面熱傳分析 ……………………………………
6-2-1 壁面熱傳係數計算方式 …………………………..
6-2-2 壁面熱傳係數之分析 ……………………………..
第七章 局部壁面噴流之暫態流場溫度表現與冷卻行為分析
7-1 流場及壁面暫態溫度表現 …………………………
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7-1-1 暫態流場溫度等級 ………………………………..
7-1-2 暫態壁面溫度等級 ………………………………..
7-2 流場及壁面之降溫幅度分析 …………………………
7-2-1 流場降溫幅度與降溫速率分析 …………………..
7-2-2 壁面降溫幅度與降溫速率分析 …………………..
7-3 壁面熱傳暫態現象分析 ………………………………
第八章 結論與未來展望
8-1 結論 ……………………………………………………
8-2 未來展望 ………………………………………………..
圖 表
參考文獻
作者簡歷
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