微結構對於奈米碳管的熱傳導係數之效應

Effects of Microstructure on the Thermal Conductivities of Carbon Nanotubes

趙文汛(Wen-Hsun Chao)

指導教授 ： 余念一

元智大學/工程學院/機械工程學系/碩士(2007年)

摘要

本研究應用雙重內含物模型來估算奈米碳管的熱傳導性質。奈米碳管可考慮視為一個雙重內含物，外部的單晶石墨視為一內含物，內部的空洞則可視為另一內含物。本文模型利用均質化的概念並且包含微結構的參數，例如碳管的管徑、長度與長徑比。最後驗證此模型之有效性，將所估算的結果與熱傳導係數實驗結果作比較。

結果顯示，所估算奈米碳管的熱傳導係數介於1241~1974 W/m-K。奈米碳管會因碳管的管徑大小影響其熱傳導性質，但與碳管長度無關。實驗所得數據與理論估算值相驗證，其兩者結果相當接近。

關鍵字

奈米碳管 ； 熱傳導係數 ； 模型

並列摘要

The thermal conductivities of carbon nanotubes (CNTs) are estimated by using the double-inclusion model (Nemat-Nasser and Hori, 1999), where one inclusion (the inner void) is embedded in the other (the outer single-crystal graphite shell).

The concept of homogenization is utilized and vital microstructural variables such as CNT diameter, length and aspect ratio are included in the present model. The interaction between the microstructure and the thermal conductivities of CNTs are quantitatively characterized. To check the validity of the developed analytic model, the thermal conductivity experiments are performed and benchmarked with the present model.

Our results show that the thermal conductivities of CNT are 1241~1974 W/m-K. The thermal conductivity is found to be strongly dependent of the diameter of CNT with little dependence on the length of CNT. The thermal conductivities of CNTs increase with an increase in CNT aspect ratio. In addition, the experimental results obtained agree well with theoretical predictions.

並列關鍵字

carbon nanotube ； thermal conductivity ； model

參考文獻

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