Non-Fourier heat conductions in nanomaterials

We study the non-Fourier heat conductions in nanomaterials based on the thermomass theory. For the transient heat conduction in a one-dimensional nanomaterial with a low-temperature step at both ends, the temperature response predicted by the present model is consistent with those by the existing theoretical models for small temperature steps. However, if the step is large, the unphysical temperature distribution under zero predicted by the other models, when two low-temperature cooling waves meet, does not appear in the predictions by the present model. The steady-state non-Fourier heat conduction equation derived by the present model has been applied to predict the effective thermal conductivities of nanomaterials. The temperature and size dependences of effective thermal conductivities of nanofilms, nanotubes, and nanowires from the present predictions agree well with the available data from experiments in the literature and our molecular dynamics simulation results, which again proves the validity of the proposed heat conduction equations. The present analysis suggests that the inertial effect of high-rate heat and the interactions between heat and surface in confined nanostructures dominate the non-Fourier heat conduction in nanomaterials. (C) 2011 American Institute of Physics. [doi:10.1063/1.3634078]