奈米碳管叢之表面熱對流效率探討

Abstract

自奈米碳管被發現以來，一直是備受矚目的研究對象，其優秀的機械性質使得大眾對於其應用方面備感興趣，而本研究也是其一。 本研究先探討填鐵奈米碳管於純鋁基材上之生長參數，成長出不同高度以及結構之填鐵奈米碳管叢，再以實驗法來探討填鐵奈米碳管叢對於表面自然對流的影響，藉由量測填鐵奈米碳管叢表面散熱情形，比較在相同環境下、無奈米碳管叢之試片量測數據，探討填鐵奈米碳管的散熱能力與特性，並研究不同高度與結構的填鐵奈米碳管叢對表面熱對流之影響。 本研究發現成長填鐵奈米碳管叢在材料表面時，可以增加近30至50%之自然對流熱交換率，且和環境溫差成正相關，亦即試片和環境之溫差愈大，對流效應導致散熱供率增加之效果愈好。而研究也發現，填鐵奈米碳管對於表面熱對流之增幅效應，並不會隨著高度變化而有所改變，將之做為鰭片狀之形貌也無助於增加散熱效率，說明了填鐵奈米碳管對表面對流之增益乃源自其優異的軸向熱傳導特性。

The research of carbon nanotubes (CNTs) has been remarkable since it was discovered. The excellent promising mechanical properties of CNTs are the most interesting reasons to research. So does the motivation of this thesis. This thesis discusses the growth procedure of the iron-filled CNTs which is synthesized on aluminum substrate. After synthesizing the different heights and structures of iron-filled CNTs, the effect of the natural convection for iron-filled CNTs by experiment processing are also be mentioned. In the same environment, it compares the ability of heat dissipation efficiency which caused by natural convection between the sample of iron-filled CNTs and the other without. After that, there is an analysis of heat dissipation efficiency for the iron-filled CNTs in different heights and structures. In this research, the material surface with iron-filled CNTs improves heat convection efficiency from 30% to 50%, which is proportional to the temperature difference between the specimen and environment. The effect on the higher iron-filled CNTs is similar, and even the one in fin-like still not able to perform better heat dissipation efficiency. Therefore, we can conclude that the gain of the convection by iron-filled CNTs is due to the outstanding axial thermal conductivity.