Shear-thickening of dense bidispersed suspensions

TL;DR

This study investigates how varying the size ratio in dense bidispersed suspensions affects their shear-thickening behavior, revealing that larger particles improve flowability by enhancing packing efficiency and reducing contact contributions to viscosity.

Contribution

It demonstrates that increasing the size ratio in bidispersed suspensions enhances flowability by improving packing efficiency, a novel insight into suspension rheology.

Findings

Larger particles increase suspension packing efficiency.

Enhanced packing reduces contact contribution to viscosity.

Flowability improves with higher dispersion ratio.

Abstract

We study the rheological behaviour of a dense bidispersed suspension varying the relative size of the two dispersed phases. The main outcome of our analysis is that an enhanced flowability (reduced relative viscosity) of the suspension can be achieved by increasing the dispersion ratio of the phases. We explain the observed result by showing that the presence of large particles increases the packing efficiency of the suspension, leading to a reduction of the contribution of the contacts on the overall viscosity of the suspension in the shear-thickening regime, i.e. where the contacts are the dominating component.