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Full-Text Articles in Mechanical Engineering
Thermal Conductivity Reduction Through Isotope Substitution In Nanomaterials: Predictions From An Analytical Classical Model And Nonequilibrium Molecular Dynamics Simulations, Ganesh Balasubramanian, Ishwar K. Puri, Michael C. Bohm, Frederic Leroy
Thermal Conductivity Reduction Through Isotope Substitution In Nanomaterials: Predictions From An Analytical Classical Model And Nonequilibrium Molecular Dynamics Simulations, Ganesh Balasubramanian, Ishwar K. Puri, Michael C. Bohm, Frederic Leroy
Ganesh Balasubramanian
We introduce an analytical model to rapidly determine the thermal conductivity reduction due to mass disorder in nanomaterials. Although this simplified classical model depends only on the masses of the different atoms, it adequately describes the changes in thermal transport as the concentrations of these atoms vary. Its predictions compare satisfactorily with nonequilibrium molecular dynamics simulations of the thermal conductivity of 14C–12C carbon nanotubes as well as with previous simulations of other materials. We present it as a simple tool to quantitatively estimate the thermal conductivity decrease that is induced by isotope substitution in various materials.
Heat Conduction Across A Solid-Solid Interface: Understanding Nanoscale Interfacial Effects On Thermal Resistance, Ganesh Balasubramanian, Ishwar K. Puri
Heat Conduction Across A Solid-Solid Interface: Understanding Nanoscale Interfacial Effects On Thermal Resistance, Ganesh Balasubramanian, Ishwar K. Puri
Ganesh Balasubramanian
Phonons scatter and travel ballistically in systems smaller than the phonon mean free path. At larger lengths, the transport is instead predominantly diffusive. We employ molecular dynamics simulations to describe the length dependence of the thermal conductivity. The simulations show that the interfacial thermal resistance Rk for a Si-Ge superlattice is inversely proportional to its length, but reaches a constant value as the system dimension becomes larger than the phonon mean free path. This nanoscale effect is incorporated into an accurate continuum model by treating the interface as a distinct material with an effective thermal resistance equal to Rk .