Interfacial layer simulation and effect on Cu-Ar nanofluids thermal conductivity using molecular dynamics method

To investigate the adsorption characteristics of interfacial layer around nanoparticle surface and its effect on nanofluids thermal conductivity, a molecular dynamics simulation is performed with the well-known Cu-Ar nanofluids system in the present paper. Several typical parameters including nanoparticle volume fraction (0%-3%), nanoparticle size (2 nm-6 nm) and temperature (85 K-130 K) are considered and discussed in detail. All the simulation results indicate that the addition of Cu nanoparticles changes the density and potentials distributions of Ar base fluid. The interfacial layer can be formed around the nanoparticles and their thickness are significantly affected by nanoparticle diameter but not nanoparticle volume fraction and temperature. In addition, adding more nanoparticles with smaller diameter will obviously increase the thermal conductivity of Cu-Ar nanofluids. On this basis, the comparison analysis is carried out to quantitatively evaluate the modeling performance of two thermal conductivity models with interfacial layer. It is demonstrated that interfacial layer plays a crucial role for theoretically predicting the thermal conductivity of nanofluids.