臺灣博碩士論文加值系統

摘要
本研究係以實驗方法探討閉孔式發泡鋁之機械行為、熱物理以及熱傳性質。在機械行為部份，本實驗研究著重於不同孔隙率測試樣品之壓縮應力－應變曲線，緻密區應變(densification strain)以及能量吸收效應等，並得到標準化降伏應力(normalized yield stress)與相對密度(relative density)之經驗修正公式。屬於熱物理性質的熱傳導係數亦已求得，並與較早之理論預測結果進行比對。對於衝擊吸收(impact absorption)與熱阻絕(thermal insulation)設計等實際應用方面之最佳參數也有探討。
此外也完成了閉孔式發泡鋁多流道熱傳之實驗研究，不同實驗參數如發泡孔隙率( , 76.78%, 84.31%, and 92.53%)，流道個數( , 4, and 9)與雷諾數(Re=1500, 3000, and 4500)等均已完成審驗比對。實驗結果不同參數會引發不同熱傳量的變動，如較高孔隙率會導致較差之熱傳量，單一系統之有效紐塞數幾與流道個數平方根成比例等。
至於雷諾數的影響也相當重要，為瞭解熱傳與強制對流之關聯性，不同測試條件下之 經驗公式亦已完成，可提供相關研究者作為參考。
關鍵字：閉孔式發泡鋁，衝擊吸收，熱絕緣

ABSTRACT
This study experimentally investigates the mechanical behaviors, thermophysical and heat transfer properties of closed-cell Al foams. The discussions on mechanical behaviors cover the compressive stress–strain curve and the densification strain and energy absorption effects of various specimens with various porosities. An empirical correlation between the normalized yield stress and the relative densities is acquired. The thermal conductivity of the aluminum foams is determined, and the results are compared with some theoretical predictions. The optimum parameters for meeting some practical design requirements, such as impact absorption and thermal insulation design applications, are discussed. Moreover, an experimental study of heat transfer in multi-channels of closed-cell aluminum foams is also conducted.
The parameters of foam porosity ( , 76.78%, 84.31%, and 92.53%), quantity of flow passage ( , 4, and 9), and Reynolds number (Re=1500, 3000, and 4500) are examined. The experimental results revealed that each parameter can trigger some heat transfer variations. The higher porosity induced less heat transfer, the value of effective Nusselt number of each system was almost proportional to the square root of flow passage quantity, and the influence of Re was also very crucial.
To understand the connection between heat transfer and forced convection, correlations were also completed for various test conditions, providing a valuable reference for associated researchers.
Keywords: closed-cell aluminum foams, impact absorption, thermal insulation

目 錄
頁次
中文摘要 Ⅰ
英文摘要 Ⅱ
誌謝 Ⅳ
目錄 Ⅴ
表目錄 Ⅵ
圖目錄 Ⅷ
符號說明 Ⅹ
第一章 緒論 1
1-1 研究動機及背景 1
1-2 文獻回顧 2
1-3 研究目的 5
1-4 研究進行步驟流程 7
第二章 理論分析 8
第三章 實驗設備與程序 12
3-1機械性質測試之實驗方法與程序 13
3-2熱傳導率測定實驗方法與程序 16
3-3熱對流參數測定實驗方法與程序 18
3-4誤差分析 23
第四章 結果與討論 30
4-1機械性質測試結果 30
4-2熱傳導率測試結果 34
4-3熱對流測試結果 34
第五章 結論 57
5-1 結論 57
5-2 研究貢獻 58
參考文獻 60













表 目 錄
頁次
表3-1 資料測試區段和測試條件的實驗特性參數值 20
表3-2 實驗工作流體相關性質 23
表4-1 不同加熱量之k值關聯式係數(解析法) 38
表4-2 不同加熱量之k值關聯式係數(JIS法) 39
表4-3不同孔隙率無因次係數 和 的詳細數值表 40












圖 目 錄
頁次
圖3-1 壓縮應變40%之發泡鋁材表面孔隙形貌圖 14
圖3-2 閉孔式發泡鋁的SEM圖( ) 15
圖3-3 熱傳導率測定法(JIS) 17
圖3-4 熱對流參數測定實驗裝置 21
圖3-5 加熱器、熱電偶和閉孔式發泡鋁的測試部位
( , 4, and 9) 22
圖4-1 發泡材料在壓縮負載期間，三個應變區說明
(1)彈性區域(2)壓縮平坦區域，和(3)緻密區域。 41
圖4-2 不同孔隙率下閉孔式發泡鋁之壓縮壓力－
應變分佈(一般) 42
圖4-3 不同孔隙率下閉孔式發泡鋁之壓縮壓力－
應變分佈(低應變) 43
圖4-4 壓縮標準化應力-相對密度分佈之相關理論預測與經驗
公式，並與目前研究(實驗數據以及經驗公式)比較 44
圖4-5 先前與目前實驗研究之緻密應變與相對密度分佈比較
(實驗數據和經驗公式) 45
圖4-6 不同相對密度發泡鋁之能量吸收性質 46
圖4-7 不同孔隙率中，理論模型和實驗資料值的高溫傳導性
分佈圖 47
圖4-8 不同孔隙率( )下， 對 的分佈情形 48
圖4-9 不同孔隙率( )下， 對 的分佈情形 49
圖4-10 不同流道數量( )下， 對 的分佈情形 50
圖4-11 不同流道數量( )下， 對 的分佈情形 51
圖4-12 不同雷諾數 下， 對 的分佈情形 52
圖4-13 不同雷諾數 下， 對 的分佈情形 53
圖4-14 不同孔隙率( )下，平均紐塞數( )對雷諾數 之
分佈情形及其經驗公式 54
圖4-15 多流道之熱傳結果與層流區經驗公式之比較 55
圖4-16 多流道之熱傳結果與紊流區經驗公式之比較 56

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