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ISSN Online: 2377-424X

ISBN CD: 1-56700-226-9

ISBN Online: 1-56700-225-0

International Heat Transfer Conference 13
August, 13-18, 2006, Sydney, Australia

MOLECULAR DYNAMICS SIMULATION OF QUASI-BALLISTIC HEAT CONDUCTION IN CARBON NANOTUBES

Get access (open in a dialog) DOI: 10.1615/IHTC13.p8.260
13 pages

Аннотация

The paper reports series of molecular dynamics (MD) studies on heat conduction of single-walled carbon nanotubes (SWNT). The length-dependence of heat conduction is quantified for a range of nanotube-lengths (25 nm<L<3.2 μm), and the tasks of diffusive and ballistic phonon transports are investigated. The influence of the boundary condition on measuring the thermal conductivity by means of non-equilibrium MD simulations is clarified and modification of appreciable boundary effects is demonstrated. With the modified boundary condition, the length-dependence of the thermal conductivity varies from previously reported simple power-law divergence. The study is further extended to investigate SWNT isotope superlattices where the quasi-ballistic phonon transport gives rise to the minimum thermal conductivity for a certain period thickness even for the length of SWNT considerably shorter than the expected phonon mean free path. Finally, a direct observation of phonon transport of relatively short nanotubes was conducted by non-stationary MD simulations. Non-Fourier heat conduction was observed where modal analyses reveal the major contribution from a range of optical phonon modes. The overall results suggest various phonon transport characteristics for different regimes of nanotube-length (L); the small L regime with significant contribution from quasi-ballistic transport of diverse phonon branches including optical phonons and the large L regime with dominant contribution of 1D-phonons with ballistic length much longer than 3.2 μm.