The rheology of concentrated suspensions of arbitrarily-shaped particles

TL;DR

This paper introduces an improved effective-medium theory to accurately predict the viscosity of suspensions with particles of arbitrary shapes across various concentrations, enhancing existing models and aligning well with experimental data.

Contribution

The authors develop a versatile continuum-medium model that incorporates particle shape and correlations, extending viscosity predictions to complex particle geometries.

Findings

Model accurately predicts viscosity for various particle shapes.

Significant improvement over previous models like Krieger-Dougherty.

Excellent agreement with experimental and simulation data.

Abstract

We propose an improved effective-medium theory to obtain the concentration dependence of the viscosity of particle suspensions at arbitrary volume fractions. Our methodology can be applied, in principle, to any particle shape as long as the intrinsic viscosity is known in the dilute limit and the particles are not too elongated. The procedure allows to construct a continuum-medium model in which correlations between the particles are introduced through an effective volume fraction. We have tested the procedure using spheres, ellipsoids, cylinders, dumbells, and other complex shapes. In the case of hard spherical particles, our expression improves considerably previous models like the widely used Krieger-Dougherty relation. The final expressions obtained for the viscosity scale with the effective volume fraction and show remarkable agreement with experiments and numerical simulations at a large variety of situations.