A unifying mechanism to explain the rate dependent rheological behavior in non-Brownian suspensions: One curve to unify them all

TL;DR

This paper introduces a unifying model based on the Stribeck curve to explain the complex shear rheology of dense non-Brownian suspensions, accurately capturing shear thinning, Newtonian plateau, and shear thickening behaviors across shear rates.

Contribution

The paper presents a novel unifying mechanism using the Stribeck curve to explain diverse rheological behaviors in non-Brownian suspensions, validated by experimental data.

Findings

Model accurately reproduces experimental rheological data.

Non-DLVO forces and asperity deformation explain rheological regimes.

Unified curve captures shear thinning, plateau, and thickening behaviors.

Abstract

We propose a unifying mechanism based on the Stribeck curve for the coefficient of friction between the particles to capture the shear thinning - Newtonian plateau - shear thickening - shear thinning rheological behavior at low - intermediate - beyond critical - high shear rates, respectively, for a typical dense non-Brownian suspension. We establish the accuracy of the proposed model by comparing the numerical results with experimental data. The presence of non-DLVO (Derjaguin and Landau, Verwey and Overbeek) forces and a coefficient of friction reducing with asperity deformation explain the existence of the Newtonian plateau at the intermediate shear rates and the second shear thinning regime at high shear rates, respectively.