Molecular dynamics simulation of fluid flow passing through a nanochannel: Effects of geometric shape of roughnesses

In this paper, we investigate the effects of geometric shape of various roughnesses on the fluid flow passing through a nanochannel by using of molecular dynamics simulation. The results of simulations are presented for the modeled structures (the five models defined) as number density, velocity, and system temperature profiles for various conditions. By applying roughness to the inner surface of the ideal nano-channel at a thrust force of 0.002 eV/A, the amplitude of number density of the fluid particles near the walls decreased, while the mean and maximum velocities increased by 6.5% and 2.5% in the presence of square cuboid and hemispheroid roughness, respectively. Furthermore, the dimensionless slip velocity and slip length were, respectively, increased by a maximum of 41.1% and 21.5% in the presence of square cuboid roughness and by a minimum of 0.9% and 0.5% in the presence of hemispheroid roughness. The temperature of the particles at the center of the nano-channel was increased by a maximum of 9.1% and a minimum of 2.8% in the presence of square cuboid and hemispheroid roughness, respectively. Calculation of the Argon-Argon radial distribution function indicated that the maximum of this function decreased by a maximum of 11.8% and a minimum of 8.5% in the presence of rectangular cuboid and ellipsoid roughness, respectively, compared to the ideal nano-channel. (C) 2018 Elsevier B.V. All rights reserved.