Molecular dynamics simulation of interface thermal resistance of graphene/sodium acetate trihydrate composite phase change material
Adding high thermal conductivity materials to salt hydrate phase change materials is an effective approach to promote the thermal performance of salt hydrates.However,significant thermal resistance occurs at the interfaces when different materials are combined.In this study,molecular dynamics simulations were employed to calculate the temperature distribution,thermal conductivity,radial distribution function(RDF)and phonon density of states(PDOS)in solid and liquid states,respectively,to investigate the atomic distribution,heat transport,and phonon transport at the interface of sodium acetate trihydrate(SAT)and graphene composite materials to explore the mechanism behind interface thermal resistance from a microscopic perspective.Temperature calculation results indicated that in both solid and liquid states,significant temperature gradients existed at the graphene/SAT interface with a thermal resistance at the interface approximately 4.5 times greater than that of other regions.RDF calculations revealed that in the solid state of graphene/SAT composite materials,the distance between graphene surface atoms increased,forming a vacuum layer,while in the liquid state,the atomic aggregation occurred on the graphene surface.PDOS calculations demonstrated that the addition of graphene disrupted the low-frequency phonon distribution in the vicinity of the interface,leading to increased phonon scattering,and then reduced thermal efficiency.This disruption diminished with increasing distance from graphene and essentially disappeared at 3nm.
sodium acetate trihydrategraphenemolecular dynamicinterface thermal resistancephonon densities of states
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