A study of viscosity inhomogeneity in porous media

Abstract

The theory of transport in highly inhomogeneous systems, developed recently by Pozhar and Gubbins, and the nonequilibrium molecular dynamics ͑NEMD͒ technique are employed to study the viscosity of WCA fluids confined in narrow slit pores of width 5.1 and 20 at reduced densities 3 of 0.422-0.713. Calculated quantities include the equilibrium and nonequilibrium density profiles, equilibrium pair correlation functions, flow velocity profiles, and the viscosity profiles. NEMD simulation results are compared with the theoretical predictions. The agreement is good except for the region within one molecular diameter from the walls. The viscosity was found to vary with position across the pore.

A molecular dynamics study of perturbed Poiseuille flow in a nanochannel

“…15 and 16 that the temperature profile experiences a large jump in the layer close to the boundaries. This large temperature jump has also been reported by independent studies Akhmatskaya 1997). Figure 19 depicts this jump for the sinusoidally forced flow.…”

Flow and slip transition in nanochannels

“…Since the fluid velocity distribution in nanochannels remains parabolic even in channels of a few nanometers [6,32,34] and the viscosity variation in channels of ß100 nm is negligible [35], the discrepancy between the experiments and theory at relatively high pressure drops must be caused by the flow slip at the channel surfaces, where the fluid velocity is nonzero. With slip correction, Eq.…”

Shear viscosity of simple fluids in porous media: molecular dynamic simulations and correlation models

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