Thermal conductivity enhancement of paraffins by increasing the alignment of molecules through adding CNT/Graphene

Conference Name: 49th Annual Technical Meeting of the Society of Engineering Science
Location: Atlanta, Georgia
Date: 2012

List of Authors:

Hasan Babaei, Pawel Keblinski, Jay M. Khodadadi

Abstract

By utilizing molecular dynamics (MD) simulations, we investigate the relationship between the crystalline structure of paraffins (n-octadecane as specific material) and its thermal conductivity and the thermal conductivity enhancement achieved by increasing the alignment of paraffin molecules in a particular direction by introducing cylindrical carbon nanotubes (CNT) and planar grapheme sheets into the paraffin. We observed that the thermal conductivity of a perfect crystalline structure in the direction of molecular axis is nearly one order of magnitude greater than the thermal conductivity value for the regular paraffin solid. Our results indicate that introducing CNT and graphene into paraffin leads to a considerable enhancement in thermal conductivity along the direction parallel to the CNT’s symmetry axis or graphene plane. This happens due to the fact that these nanofillers increase the alignment of molecules along a particular direction. An alignment parameter was defined to quantitatively study the relationship between the thermal conductivity and the alignment of molecules along a particular direction. The calculations show that, generally, the thermal conductivity increases with the alignment parameter.