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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Thermal Conductivity of Silicon Nanofilms Predicted by Combined Phonon Hydrodynamics and Phonon Gas Dynamics

Get access (open in a dialog) DOI: 10.1615/IHTC15.tpp.008917
pages 8909-8916

摘要

A prediction model for the effective thermal conductivity of silicon nanofilm is proposed based on combined phonon hydrodynamics and phonon gas dynamics. According to the thermomass theory we present a macroscopic picture of the heat conduction, which is the phonon gas passing through a porous media. There are two resistant terms in the momentum equation of phonon gas. The first is the Darcy term, which is proportional to the drift velocity of phonon gas and leads to the Fourier conduction law for bulk materials. The second is the Brinkman term, which reflects the viscous boundary effect region and needs to be considered in nanosystems. The rarefication effect in nanosystems is characterized by the mean free paths modification algorithm. Then a quantitative relationship is obtained between the effective thermal conductivity of silicon and the film thickness by means of the solution of the phonon gas momentum equation. The present model predicts well the temperature and size dependence of the in-plane thermal conductivity of Si nanofilms.