Rheology and structure of a suspension of deformable particles in plane Poiseuille flow

TL;DR

This study experimentally investigates how deformable particles like red blood cells influence flow behavior and structure in confined microfluidic channels, confirming simulation predictions and revealing complex viscosity-concentration relationships.

Contribution

First experimental validation of the link between suspension structure and rheology in confined deformable particle flows, previously only shown in simulations.

Findings

Strong structuring effects due to confinement influence viscosity.

Distinct regimes of viscosity growth and plateaus linked to structural transitions.

Experimental confirmation of simulation-based relationships in 3D particle suspensions.

Abstract

We present an experimental study of the rheology and structure of a confined suspension of deformable particles flowing in a quasi-two-dimensional Poiseuille flow. Thanks to a precise microfluidic viscosimetry technique combined with measurements of concentration profiles, our study provides the first experimental confirmation {with three-dimensional particles} of a strong relationship between structuring effects and rheology, previously only reported in numerical simulations of purely two-dimensional systems. In conditions where strong structuring effects take place due to confinement, the evolution of the effective viscosity with particle concentration (here, red blood cells) shows a remarkable succession of ranges of rapid growth and plateaus that are associated to qualitative transitions in the structure of the suspension.