AUGMENTED SOLUTE TRANSPORT IN THE SHEAR FLOW OF A CONCENTRATED SUSPENSION.

An improved understanding of the transport processes involved in the shear flow of concentrated suspensions, including blood, is important in many industrial and clinical processes. We propose that augmented solute transport arises from shear-induced particle migrations and the concomitant dispersive fluid motion induced by these particle migrations. Random particle motion is described by a shear-induced diffusion coefficient evaluated from literature data on the lateral migrations of labelled particles in well-defined flow systems. The effective diffusivity characterizing the random fluid motion induced by the particle migrations is shown to be equal to the shear-induced particle diffusivity. Augmented solute transport arising from dispersive particle and fluid motion varies linearly with the particle Peclet number; for the case of deformable particles, augmentation is maximal at a volume fraction of about 0. 5. Model predictions are in agreement with experimental data from a variety of experimental systems.