Research Paper

Microfluidics and Nanofluidics

, Volume 17, Issue 6, pp 1011-1023

A quasi-continuum multi-scale theory for self-diffusion and fluid ordering in nanochannel flows

  • Antonios E. GiannakopoulosAffiliated withDepartment of Civil Engineering, School of Engineering, University of Thessaly
  • , Filippos SofosAffiliated withDepartment of Civil Engineering, School of Engineering, University of Thessaly
  • , Theodoros E. KarakasidisAffiliated withDepartment of Civil Engineering, School of Engineering, University of Thessaly Email author 
  • , Antonios LiakopoulosAffiliated withDepartment of Civil Engineering, School of Engineering, University of Thessaly

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Abstract

We present a quasi-continuum self-diffusion theory that can capture the ordering effects and the density variations that are predicted by non-equilibrium molecular dynamics (NEMD) in nanochannel flows. A number of properties that affect fluid ordering in NEMD simulations are extracted and compared with the quasi-continuum predictions. The proposed diffusion equation requires the classic diffusion coefficient D and a micro structural internal length g that relates directly to the shape of the molecular potential of the NEMD calculations. The quasi-continuum self-diffusion theory comes as an alternative to atomistic simulation, bridging the gap between continuum and atomistic behavior with classical hydrodynamic relations and reduces the computational burden as compared with fully atomistic simulations.

Keywords

Quasi-continuum theory Molecular dynamics Self-diffusion equation Nanochannel flows Fluid ordering Density profile oscillations