Investigation of interfacial thermal resistance of bi-layer nanofilms by nonequilibrium molecular dynamics

2015

Int J Thermophys

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Solid-liquid systems widely exist in micro-and nanodevices, and it is necessary to study the heat transfer mechanism through solid-liquid interfaces. An asymmetrical sandwich structure of a solid-liquid system consisting of liquid argon and artificial solid walls that have the same FCC structure with argon but a different atomic masses is composed. Heat transfer characteristics are investigated by the molecular dynamics method. The interaction strength between a liquid and solid plays an essential role in heat transport at solid-liquid interfaces, and the thermal resistance length is inversely proportional to it. The mass arrangement of artificial solid walls also has a significant effect on heat transport as well. A maximum heat flux comes up due to the mismatch in phonon spectra with the increasing atomic mass of one solid wall. The asymmetrical liquid density profiles are obtained with various mass differences between solid walls. Especially, a thermal rectification effect is observed and the magnitude is inextricably bound up with asymmetry.

Section: Effect Of Atomic Mass Of Solid Wallmentioning

confidence: 96%

Heat Transfer Characteristics in an Asymmetrical Solid–Liquid System by Molecular Dynamics Simulations

Feng

2015

Int J Thermophys

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“…The thermal rectification has such a feature that its thermal resistance is dependent on heat flow direction. [2][3][4][5][6][7][8][9][10][11][12][13] It can be designed by investigating its mechanism. At present, several main explanations for thermal rectification have been proposed, such as anharmonic one-dimensional atom chain, 2-6 the difference of thermal conductivity dependence on temperature and the interfacial thermal resistance between dissimilar materials, 7,8 and the asymmetry in geometries or atom mass.…”

Section: Introductionmentioning

confidence: 99%

Thermal rectification and phonon scattering in asymmetric silicon nanoribbons

Journal of Applied Physics

2012

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Thermal rectification is an interesting phenomenon and has important potential applications in improving the thermal management of electronics and saving energy. Exploring thermal rectification phenomena and understanding the mechanism are very necessary and important. This paper reports the investigation of the thermal conductivity and thermal rectification of asymmetric silicon nanoribbons by the non-equilibrium molecular dynamics simulation. The results indicate that the thermal conductivity of the nanoribbon is only on the order of 100 Wm−1K−1. Thermal rectification is observed in silicon nanoribbons at different temperatures, geometry aspects, and ribbon length. The thermal conductivity is apparently larger when heat flows from the thin end to the thick end. The larger the aspect ratio of the thick end to thin end is, the larger the thermal rectification. The rectification coefficient does not change much in the ribbon length ranges from 8.1 nm to 21.7 nm. The longitudinal phonon scattering in the silicon nanoribbon at different frequency is investigated by the phonon wave packet dynamic simulation. The results show that the phonon transmission coefficient is sensitive to frequency and transverse phonons are generated during the scattering. Decreasing the thin end width will reduce the transmission coefficient due to the scattering at the slope boundary.

“…Solid argon is selected as the simulation material for its simple potential function, and because its thermal conductivity is also widely simulated or measured by researchers [1][2][3][4][5]10]. As argon is an inert element and a dielectric material, we only consider the phonon transport that dominates the thermal conductivity, without considering the electrons or their interactions with phonons.…”

Section: Simulation Methodsmentioning

confidence: 99%

“…Molecular dynamics (MD) simulation has become a widely used method to investigate the thermal conductivity of single-crystal nanofilms during the last decade because of its low cost and high efficiency [1][2][3][4][5]. As an example, Lukes et al [1] studied the feasibility of using the MD computational technique to predict the normal thermal conductivity of solid argon thin films, and their result shows that the thermal conductivity increases with the atomic layer number.…”

mentioning

confidence: 99%

An atomic level study on the out-of-plane thermal conductivity of polycrystalline argon nanofilm

2012

Chin. Sci. Bull.

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At present, there have been few direct molecular dynamics simulations on the thermal conductivity of polycrystalline nanofilms. In this paper, we generate polycrystalline argon nanofilms with random grain shape using the three-dimensional Voronoi tessellation method. We calculate the out-of-plane thermal conductivity of a polycrystalline argon nanofilm at different temperatures and film thicknesses by the Muller-Plathe method. The results indicate that the polycrystalline thermal conductivity is lower than that of the bulk single crystal and the single-crystal nanofilm of argon. This can be attributed to the phonon mean-free-path limit imposed by the average grain size as well as the grain boundary thermal resistance due to the existence many grain boundaries in polycrystalline materials. Also, the out-of-plane thermal conductivity of the polycrystalline argon nanofilm is insensitive to temperature and film thickness, and is mainly dominated by the grain size, which is quite different from the case of single-crystal nanofilms.thermal conductivity, polycrystalline, argon nanofilm, molecular dynamics simulation