Molecular dynamics study of nanofluids viscosity with carbon tubes

The purpose of this paper is molecular dynamics simulation of viscosity of benzene-based nanofluids with carbon nanotubes, and carbon or copper nanoparticles. The nanotubes diameter and lengths were 1.1 nm and 1.1, 3.5, 7.2, 14.6 nm, respectively. The size of spherical nanoparticle was 1.39, 2.5, and 3.2 nm. The viscosity is calculated using the fluctuation-dissipation theorem (the Green–Kubo formula). It was shown that the viscosity coefficient of all the studied nanofluids with carbon nanotubes increases with their concentration and length. This increase is significantly higher than predicted by the corresponding theories for coarse dispersed fluids. At given weight concentrations, the viscosity coefficient of nanofluids with carbon nanotubes is higher than that of nanofluids with spherical particles. The increase in viscosity of nanofluids compared to that of the base fluid is explained by the structuring of the base fluid molecules in the vicinity of nanoparticles or carbon nanotubes.