Transport in a highly asymmetric binary fluid mixture

TL;DR

This study uses molecular dynamics to analyze thermal conductivity and viscosity in a colloidal suspension with large particles, comparing results with theoretical models and exploring effects of particle mass on transport properties.

Contribution

It demonstrates the applicability of effective medium theories for predicting transport properties in suspensions with typical colloidal particle masses and highlights deviations for very light particles.

Findings

EMT accurately predicts viscosity and thermal conductivity for typical colloids.

Light colloidal particles increase thermal conductivity beyond EMT predictions.

Results inform mechanisms of thermal conduction in nanocolloidal suspensions.

Abstract

We present molecular dynamics calculations of the thermal conductivity and viscosities of a model colloidal suspension with colloidal particles roughly one order of magnitude larger than the suspending liquid molecules. The results are compared with estimates based on the Enskog transport theory and effective medium theories (EMT) for thermal and viscous transport. We find, in particular, that EMT remains well applicable for predicting both the shear viscosity and thermal conductivity of such suspensions when the colloidal particles have a ``typical'' mass, i.e. much larger than the liquid molecules. Very light colloidal particles on the other hand yield higher thermal conductivities, in disagreement with EMT. We also discuss the consequences of these results to some proposed mechanisms for thermal conduction in nanocolloidal suspensions.