The effect of the thermal vibration of graphene nanosheets on viscosity of nanofluid liquid argon containing graphene nanosheets

The impact of the thermal vibration of graphene nanosheets on viscosity and diffusion coefficient of nanofluid liquid argon containing graphene nanosheets are investigated by means the molecular dynamics simulation (MDS) combined with Green-Kubo formalism and the Einstein's formula respectively, and the hybrid BNC Tersoff potential is used to describe the interactions inter-atomic in graphene nanosheet. The numerical calculations of viscosity and diffusion coefficient are executed in the temperature range of 84-92 K and for graphene nanosheets volume fractions which are 3.93 vol%, 5.01 vol%, 6.88 vol% and 9.74 vol%. Firstly, the molecular dynamics code, the Green-Kubo framework and Einstein's formula are confirmed by comparing the viscosity and diffusion coefficient of argon liquid, with those calculated by preceding numerical simulations (MDS) and experimental studies. The results have indicated that the shear viscosity increases and the diffusion coefficient decreases when the graphene nanosheets volume fraction increases. Furthermore, the thermal vibration of graphene nanosheet has been considered among the responsible mechanisms to be the origin of enhanced shear viscosity. (C) 2019 Elsevier B.V. All rights reserved.