The theory holds when continuum models are inappropriate due to the innate discrete nature of the medium (boundary layer and molecular scale effects) ranging from microscopic layers to discrete molecular structure. After local rapid transient fluctuations are dissipated, the energy of an <i>N</i>-atom classical system can be described by an energy field that varies slowly in time relative to the dynamics of atomic collisions and vibrations. As a result, the energy density field can serve as the basis of a multiscale theory of energy transfer between a nanoscale system and its surrounding fluid. The theory is developed based on the <i>N</i>-atom Liouville equation and the Lie-Trotter factorization with ideas similar to those used in continuum theory. The theory coevolves the energy field and the atom resolve state. The energy field is computed at a set of nodes organize in a lattice. The contributions of the atoms to the energy field is weighed by a Gaussian function center on each node. The updated energy field is obtained by extrapolating it using a linear approximation, assuming that the energy fluctuations satisfy the stationarity hypothesis. The theory is validated via multiple molecular dynamics simulations of the energy transfer between a cold nanoparticle immersed in hot water and vice-versa. The simulations results show that the theory can be use when the Gaussian width in greater or equal to the internode distance, and avoiding domains were no atoms are accounted for. Theoretically, the accelerations can be up to 10 times compared to conventional molecular dynamics.

Bridging the gap between continuous and atomistic models in heat transfer

252nd National Meeting (2016)

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