磁性流體於不同長寬比之 Hele-Shaw cell 流場中熱傳研究分析 蔡睿唐、溫志湧
E-mail: [email protected]
摘 要
本研究主要是以實驗的方式，來探討磁流體於不同長寬比之 Hele-Shaw Cell 流場中受到外加均勻垂直磁場作用與下方加熱 情 況下的Rayleigh-Benard 熱對流不穩定性問題。實驗方面改善先 前的實驗設備及實驗的環境條件，並延續使用全自動的 資料存取 系統，及藉由高精度的電阻式加熱器與熱電偶（K-Type）來精準 地控制磁流體上下邊界的恆溫條件，及使用液 晶熱像法來觀察外 加垂直磁場對流場不穩定性的影響。研究結果證明運用液晶熱像 法可將磁流體之對流流場可視化，外 加磁場可使多個不同長寬比 的磁流體Hele-Shaw cell 流場之不穩定現象提前發生。研究中並 找出不同長寬比下的臨界磁場
，Ramc，另外也發現了不同的 Hele-Shaw cell 厚度-長度比(Dh 比值)對Ra 值有相對的影響。
關鍵詞 : 磁流體，Hele Shaw Cell，長寬比，Rayleigh-Benard 熱對流不穩定性，液晶熱像法。磁性流體 目錄
封面內頁 簽名頁 授權書 ...iii 中文摘要...iv 英文摘要
...v 誌謝...vi 目錄 ...vii 圖目錄 ...ix 表目錄 ...x 符號說明 ...xi 第一章 緒 論...1 1.1 磁流體的特性與應用...1 1.2 文獻回顧...2 1.3 研究目的...9 第二章 研究方法...11 2.1 統御方程式...11 2.2 實驗設備...14 2.3 液晶熱像法(Liquid Crystal Thermography) ...23 第三章 結果與討
論...29 3.1 磁流體於Hele-Shaw cell 流場中熱傳變化...29 3.2 液晶熱像法觀測流場變 化...31 第四章 結論...40 參考文獻 ...42 附錄 ...45
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