The effect of graphene layers on interfacial thermal resistance in composite nanochannels with flow

Abstract

Interfacial thermal resistance $$R_{\mathrm{th}}$$ is analysed for a typical nanoscale interface with the help of nonequilibrium molecular dynamics. Liquid argon confined between two parallel copper walls is considered. Channel walls with varying wettabilities are modelled by depositing single and double layers of graphene on the copper nanochannel. To our knowledge, this is for the first time that such an attempt is made to modify the fluid–wall interaction strength in a more realistic manner and then to study its effect on thermal transport properties at the interface. Further, the variation of $$R_{\mathrm{th}}$$ at the solid–liquid interface in a nanoscale channel is studied in detail, while the liquid is made to flow through it. The simulation results reveal that the introduction of graphene layers on copper surface resulted in an enhancement of $$R_{\mathrm{th}}$$ . In order to analyse the molecular level mechanism resulting in the variation of $$R_{\mathrm{th}}$$ , vibrational density of states (VDOS) of the interfacial layer of wall atoms and the vibrational mobility of the adsorbed fluid layer were studied. A decrease in the vibrational mobility of fluid atoms was observed in nanochannels having graphene layers. Furthermore, in the case of composite nanochannels, we observe a decrease in the degree of overlap between the VDOS of the fluid atoms and the adjacent wall atoms. The variation of slip length with the Kapitza length is also investigated inside the composite nanochannels. Our results also suggest that the introduction of graphene layers could be a practical method for modifying $$R_{\mathrm{th}}$$ at nanochannel interfaces.