DYNAMIC VISCOUS RESUSPENSION OF BIDISPERSE SUSPENSIONS .1. EFFECTIVE DIFFUSIVITY

In this paper, we describe an experimental investigation into the dyna mic viscous resuspension of bidisperse suspensions in an annular paral lel plate device. We use the model of Chapman and Leighton to determin e the effective diffusivity of the particulate phase (51.0 and 119.0 m u m glass spheres) in the plane of shear as a function of overall conc entration (0.3 < phi < 0.5) as well as the relative size fraction of t he large particles (0.0 < phi(L)/(phi(L) + phi(S)) < 1.0). The effecti ve diffusivity of a mixed suspension was found to be somewhat less tha n the volume average of the diffusivities of monodisperse large and sm all sphere suspensions.