Nanoflows through disordered media: a joint Lattice Boltzmann and Molecular Dynamics investigation

TL;DR

This study combines lattice Boltzmann and molecular dynamics simulations to analyze nanoflows through disordered media, revealing size effects on permeability and the impact of gel structure at different solid fractions.

Contribution

It introduces a joint LB and MD simulation approach to study nanoflows in disordered media, highlighting molecular size effects and permeability variations.

Findings

Permeability matches at low solid fractions ($\Phi<0.01$) between LB and MD.

Molecular size effects reduce permeability at higher solid fractions ($\Phi>0.01$).

Gels show increased permeability, adjustable by effective radius rescaling.

Abstract

We investigate nanoflows through dilute disordered media by means of joint lattice Boltzmann (LB) and molecular dynamics (MD) simulations -- when the size of the obstacles is comparable to the size of the flowing particles -- for randomly located spheres and for a correlated particle-gel. In both cases at sufficiently low solid fraction, $\Phi<0.01$, LB and MD provide similar values of the permeability. However, for $\Phi > 0.01$, MD shows that molecular size effects lead to a decrease of the permeability, as compared to the Navier-Stokes predictions. For gels, the simulations highlights a surplus of permeability, which can be accommodated within a rescaling of the effective radius of the gel monomers.