衝擊噴射在工業界是一個很重要的冷卻熱傳技術，如工業乾燥、金屬與玻璃退火、鑄鐵時的二次冷卻、雷射冷卻與電漿切割冷卻、氣渦輪葉片冷卻、微電子散熱。衝擊噴柱的熱傳增強技術，目前在學術界是正在積極探討的問題。
　　本研究採用暫態液晶熱傳技術，探討衝擊熱傳目標平板上加裝多孔材料在無挖中心孔與有挖中心孔時，與平板噴射基本情形比較的熱傳增強效果。本研究先參考平板衝擊熱傳相關實驗文獻，在相同的實驗條件下比對，驗證實驗系統是可行的，以此系統再進行平板上加裝多孔材料的衝擊熱傳的實驗。
　 實驗結果顯示加裝有中心孔的多孔材料可有效提升衝擊噴射之熱傳效果，加裝無中心孔的多孔介質對熱傳增強反而有反效果。此外，多孔介質挖孔幾何對熱傳性能有決定性的影響，最佳的中心孔幾何是讓流體可有效的穿入多介質進行熱傳。

Jet impinging is an important cooling heat transfer technique in the industries, such as industrial drying, metal and glass annealing, secondary cooling in iron casting, laser cooling, plasma cutting cooling, gas turbine blade cooling, and cooling of microelectronics. Nowadays, enhancement techniques for jet impingement heat transfer are still under intense investigation by academic researchers.
In this study, the jet impingement heat transfer on a target plate covered with porous medium with or without a center hole is experimentally investigated using the transient liquid crystal technique. Based on the results from jet impingement on a bare flat plate, the enhancement in heat transfer due to the addition of porous material is evaluated. The validity of the experimental system constructed for this research was confirmed first by comparing the experimental data of impingement on a flat plate at similar conditions in the literature. The system and the data reduction procedure were then applied to the experimental cases with the flat plate covered with a thick layer of porous medium.
Experimental results show that the addition of the porous material with a center hole can effectively enhance the jet impingement heat transfer over a flat plate. The addition of the thick porous layer without a center hole, however, gave rise to adverse effect in jet impingement heat transfer. In addition, the geometry of the center hole of the porous layer has deterministic influence on heat transfer performance. An optimal center-hole geometry will allow fluid to effectively penetrate into the porous medium for heat exchange.

封面內頁
簽名頁
授權書　　　　　　　　　　　　　　　　　　　　　　　 iii
中文摘要　　　　　　　　　　　　　　　　　　　　　 v
英文摘要　　　　　　　　　　　　　　　　　　　　　 vi
誌謝　　　　　　　　　　　　　　　　　　　　　　　 viii
目錄　　　　　　　　　　　　　　　　　　　　　　　 ix
圖目錄　　　　　　　　　　　　　　　　　　　　　　 ix
表目錄　　　　　　　　　　　　　　　　　　　　　　 xv
符號說明　　　　　　　　　　　　　　 　　　　　　xvi

第一章 導論　　　　　　　　　　　　　　　　　　　 1
1.1研究背景　　　　　　　　 　　　 　　　　　1
1.2研究目的　　　　　　　　 　　　 　　　　　3
1.3文獻回顧　　　　　　　 　　　 　　　　 　4
1.3.1噴射衝擊流研究　　　　　　　　　　　 4
1.3.2多孔介研究　　　　　　　　　　　　　 9
1.3.3加裝多孔介質或凸塊噴射衝擊　　 　　10
第二章 實驗相關理論及校正 12
2.1數據化約的基本理論 12
2.2雷諾數之計算 13
2.3噴嘴出口速度 14
2.3.1熱線風速儀　　　 　　　　　　　　　14
2.3.2微差壓計 　 　　　　　　　　　　　15
2.3.3熱線校正與速度量測結果 　　　　 　16
2.4熱偶校正與量測 16
2.5液晶校正 17
第三章 實驗設備與實驗步驟 19
3.1 影像處理系統 19
3.2 實驗系統 19
3.2.1噴嘴設計　　 　　　　　19
3.2.2實驗平台　　 　 　　　　20
3.2.3測試段　　 　　 　　　20
3.3實驗方法及步驟 21
第四章 結果與討論 23
4.1平板衝擊熱傳之紐賽數結果 23
4.1.1雷諾數的影響 23
4.1.2平板與噴嘴之間距的影響 25
4.1.3噴嘴直徑的影響 25
4.2平板加裝無中心孔多孔材料之衝擊熱傳 26
4.3平板加裝有中心孔多孔材料之衝擊熱傳 27
4.3.1有中心孔深度30mm 27
4.3.2有中心孔深度40mm 28
4.3.3挖穿之中心孔 29
4.3.4挖穿之中心孔多孔材四周有包覆 30
第五章 結論 31
參考文獻 33

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