Rheology of Concentrated Suspensions

Abstract

The rheology of concentrated suspensions, namely their viscoelasticity, is determined by the balance of three forces; Brownian diffusion, hydrodynamic interaction and interparticle forces. These three contributions depend on the volume fraction of the suspension, the particle size and interparticle forces. Thus, various viscoelastic responses may be obtained depending on the time scale of the experiment and the structure of the system. If the time scale of the experiment is shorter than the relaxation time of the system, a predominantly elastic response is produced. This means that the system has a relatively high Deborah number D_e,

$${{\text{D}}_{\text{e}}}={{\text{t}}_{\text{r}}}\text{/}{{\text{t}}_{\text{e}}}$$

(1)

where t_r is the relaxation time of the system and t_e the time scale of the rheological experiment.