Effect of water/carbon interaction strength on interfacial thermal resistance and the surrounding molecular nanolayer of CNT and graphene flake.

Abstract Heat transfer at the liquid-solid interface, especially when the particles are at nanoscale, can dominate the thermal properties of nanofluids. In this study we investigate the liquid-solid interfacial thermal resistance (Kapitza resistance) and particularly analyze the structure of the formed molecular nanolayer around the carbon-based nanoparticles. Employing non-equilibrium molecular dynamics simulation and thermal relaxation method, nanofluids systems with nanoparticles with different diameters and surface wettabilities were investigated. Simulation results reveal that carbon nanotubes (CNTs) with smaller diameters more effectively attract base fluid and thus show lower reduced Kapitza resistances. It was found that the thickness of the nanolayer around the nanoparticle is independent of the carbon/water interaction strength. As expected, it was shown that the value of Kapitza resistance decreases when the interaction strength increases. Based on our acquired results, a correlation was proposed for the interfacial thermal resistance of CNT/water and graphene/water with respect to the intensity of wettability of nanoparticles surface. The insight provided by our atomistic simulations can provide a better understanding of heat transfer in nanofluids systems wherein an accurate local description of heat transfer is crucial. Highlights • CNTs with lower diameter have less interfacial thermal resistance (ITR). • The strength between water and carbon has no effect on the thickness of nanolayer. • The ITR for CNT/water is less than that of graphene/water. • A correlation proposed for the ITR in terms of wettability of the nanoparticle. [ABSTRACT FROM AUTHOR]