A hierarchical multi-scale method to simulate reactive–diffusive transport in porous media

Abstract

A time-dependent, hierarchical multi-scale model to simulate reactive-diffusive transport in a 3-dimensional, porous structure, using a combination of molecular dynamics (MD), kinetic Monte Carlo (KMC) and Monte Carlo diffusion (MCD) methods has been developed. The parameters that are passed from the models at the lower spatial and temporal scales (MD,KMC) to those at the higher scales (KMC, MCD respectively) are identified.The advantages and disadvantages of the different methods are discussed with respect to reactive-diffusive transport simulations of atoms in porous 3D structures. The model is illustrated by simulating hydrogen transport, reactions, inventory and re-emission from a porous hydrocarbon layer.1

Diffusion of hydrogen in graphite: a molecular dynamics simulation

“…This computational technique has been also applied to study several properties of hydrogen in various carbon-based materials [26][27][28][29]. In general, finite-temperature properties of hydrogen-related defects in solids have been investigated by ab-initio and TB molecular dynamics simulations [30][31][32].…”

Modelling of hydrogen isotope inventory in mixed materials including porous deposited layers in fusion devices

“…The input data used include diffusivity, trap sites, etc. and are shown in Table 1 and Table 2, where most of these were used in MD or KMC simulations [14,15,16,25] and gleaned from either experiments (E D , E HD or an educated guess was used (like ω o corresponds to typical phonon frequency [19]). The backscattering rate R is from [27].…”

Modeling of hydrogen isotope exchange from porous graphite

“…Therefore, the physics of the interaction of hydrogen with graphite used in the fusion devices is multi-scale in space (Å to cm) and time (picoseconds to seconds). For this reason a multi-scale model has been developed [1] . The model is a hierarchical multi-scale model, wherein simulations at the lower scales or experimental results wherever available are used as inputs to the simulations at higher scales.…”

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Abstract: A 3D Kinetic Monte Carlo (KMC) model has been used to study the hydrogen isotope exchange from porous graphite at a single granule length scale (micrometers).The present KMC model is part of a previously reported multi-scale model developed by the authors [1]. SDTrimSP [2,3] simulations have been carried out and the results have been used to get some of the input parameters for the KMC where the diffusive-reactive aspect of H and D are studied.

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“…The present KMC model is part of a previously reported multi-scale model developed by the authors [1]. SDTrimSP [2,3] simulations have been carried out and the results have been used to get some of the input parameters for the KMC where the diffusive-reactive aspect of H and D are studied.…”