DIFFUSION AND VISCOUS FLOW IN CONCENTRATED SUSPENSIONS

Synopsis The principle of minimum entropy production is applied to obtain bounds on the diffusion coefficient of a solute in a suspension of solid particles, as well as on the viscosity of the suspension. These bounds involve certain two-and three-point correlations characterizing the geometry of the liquid-solid interface, but are not in any way dependent upon the adoption of a simplified model to represent the system. In particular, it is not necessary to assume that the suspended particles are too far apart to interact with one another, and the theory is therefore valid even when the volume fraction of solid is high.