MICRORHEOLOGICAL MODELS OF AGGREGATED SUSPENSIONS IN SHEAR-FLOW

Theoretical analyses are presented of three previously proposed models of the aggregation-disaggregation process, with numerically calculated predictions of the corresponding viscosity vs shear rate behavior. All the models are based on the assumption that aggregation of particles is due to surface forces of arbitrary nature and disaggregation is due to viscous stresses. The models differ from each other by the methods of taking into account hydrodynamic interaction of aggregates. Some modifications of the models are considered and different methods of the aggregates yield stress evaluation are compared. It is shown that two models (one of them is based on the mean field theory and the other utilizes the free cell theory) correspond to the diluted suspensions and the third one (based on the lubrication theory) can be applied to the suspensions of high concentration and low concentration as well. © 1991.