頁籤選單縮合
題名 | Estimation of Effective Conductivity for Aligned Elliptic Cylinder Dispersions=定向橢圓柱分散系統有效導熱度之估算 |
---|---|
作者 | 呂世源; | 書刊名 | Journal of the Chinese Institute of Chemical Engineers |
卷期 | 29:2 1998.03[民87.03] |
頁次 | 頁139-152 |
分類號 | 460.02 |
關鍵詞 | 定向橢圓柱分散系統a效導熱度; Effective conductivity; Elliptic cylinder; Contact resistance; Coated inclusion; Equivalent inclusion method; |
語文 | 英文(English) |
中文摘要 | 吾人提出一等效粒子模式,用以估算含定向橢圓柱分散系統之有效導熱度。橢 圓柱表面可以是與基材完美接觸,存在某接觸熱阻或被覆以一層第三種材料。對於一般橢 圓柱情況,發現有效導熱度張量中之平行及垂宜分量滿足Keller倒數定理,而對於被覆橢 圓柱情況,一類似於Keller定理的倒數關係可被提出。不同於一般橢圓柱狀況,在接觸熱 阻及被覆橢圓柱情況中,橢圓柱可在一方向頭出強化導熱度效應,而在另一方向展現減弱 效應。對於一般橢圓柱問題,其無因吹有效導熱度被發現是橢圓柱體積分率,橢圓柱軸長 比及無因吹橢圓柱導熱度之函數。在接觸熱阻問題中,多出一個參數,其為以半主軸長為 基準之Biot數,而在被覆橢圓柱問題中,則多出兩個參數,一為相對塗佈厚度,另一為被 覆眉之無因次導熱度。吾人完整地探討這些參數對無因吹有效導熱度之效應。 |
英文摘要 | An equivalent inclusion model is proposed to estimate the effective conductivity of dispersions containing aligned long elliptic cylinders. The cylinders are either in perfect contact with the matrix, possessive of certain contact resistance or coated with a confocal elliptic layer of a third material. The parallel and perpendicular components of the effective conductivity tensor for the plain cylinder case are shown to satisfy Keller' s reciprocal theorem, while those for the coated cylinder case follow a reciprocal relation similar to Keller's. Unlike the plain cylinder case, the inclusion effect for the contact resistance and coated cylinder cases can be enhancing in one direction, but impairing in the other direction. For the plain cylinder problem, the reduced effective conductivity (□) is found to depend on the cylinder volume fraction (f), cylinder aspect ratio (□/□), and reduced cylinder conductivity (□). One more parameter, the semi-major axis based Biot number (Bi), is needed for the contact resistance problem, while two more parameters, the reduced coating layer conductivity (□) and the relative coating thickness (δ/□), appear for the coated cylinder problem. Effects of these parameters on □ are thoroughly investigated. estigated. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。