Transient heat conduction in multiwall carbon nanotubes

In this paper, theoretical investigation is performed on two-dimensional transient heat conduction in multiwall carbon nanotubes (MWCNTs) by using a continuum model. Temperature, size and direction dependencies of thermal properties are considered. Both Fourier and non-Fourier heat conduction approaches are used and finite element models are developed to solve the nonlinear equations for MWCNTs. The presented solutions are verified by comparing the results with those reported in the literature. Three types of thick and thin MWCNTs are considered and thermal shock is applied to their cylindrical surfaces or end cross sectional areas. Temperature distributions resulted from both approaches are obtained and compared together. Interesting results are found especially in MWCNTs that are exposed to extreme temperature gradient.本文基于连续介质模型，针对多壁碳纳米管（multiwall carbon nanotubes, MWCNTs）的二维瞬态热传导问题开展理论研究。研究中考虑了热物性参数随温度、尺寸及方向的变化特性。本研究同时采用傅里叶与非傅里叶热传导分析方法，并构建有限元模型以求解多壁碳纳米管的非线性热传导方程。通过将本文求解结果与已有文献报道的结果进行比对，验证了所提解法的有效性与正确性。本次研究共选取三类粗细规格不同的多壁碳纳米管，对其圆柱表面或端面施加热冲击载荷。分别得到两种热传导方法下的温度分布结果并开展对比分析。研究获得了若干具有重要学术价值的结果，尤其在承受极端温度梯度的多壁碳纳米管体系中表现突出。