Fluid Flow at the Nanoscale: How Fluid Properties Deviate from the Bulk

Abstract

The studies of fluid flows have been lately transferred to a significant extend at the micro- and the nano-scale, since there is increasing interest in applications that could make possible the construction of systems from atoms and molecules. Apart from the experimental studies, which are still difficult to perform at the atomic scale, computer simulation has been a valuable tool for fluid flow investigation at the nanoscale. More specifically, atomistic simulation with Molecular Dynamics (MD) provides an insight at the atomic level and is the most appropriate method for nanoflow simulations. As the present study moves to the atomic scale, the existence of a critical dimension is observed below which all fluid properties studied (density, maximum velocity, temperature, slip length, diffusion coefficient, shear viscosity, and thermal conductivity) are modified and deviate from their bulk values. It is shown that this critical dimension is further affected by the nanochannel wall properties, such as the geometric roughness and wettability.