Prediction of Suspension Rheology Through Particle Motion Simulation, 1995 Coating Fundamentals Symposium Proceedings

The influence of particle size distribution on the rheological properties of concentrated suspensions is investigated. The mo-tion of mono-, bi- and polydisperse suspensions of spherical particles in shear- and pressure-driven flows is modeled using a modified stokesian dynamics technique. In bi- and polydis-perse suspensions under shear, small particles reduce suspension viscosity by breaking stress chains formed by larger particles. Small particles close to boundaries can force large particles into the bulk of the suspension. This results in size segregation where small particles concentrate on boundaries. In pressure-driven flow, the particles concentrate at the low shear rate re-gions. This leads to non-uniform particle concentrations and thixotropic behavior of the suspension. High short-duration viscosity levels characteristic for monodisperse suspensions are absent in polydisperse suspensions. Keywords: Rheology, modeling, stokesian dynamics, shear flow, pressure-driven flow.