Yield stress of suspensions loaded with size distributed particles

Abstract

A new theoretical approach is proposed for the yield stress of concentrated, flocculated particulate suspensions. Explicit cognizance is taken for the three-dimensional, mechanically rigid particle network held together by interparticle forces wherein the mean coordination number in the assemblage increases and the separation between the particles decreases with an increase in the volume fraction of the solid phase. The Rump-Molerus model relting isotropic normal stress and isotropic normal interparticle force in a bed of single-sized spheres is modified to incorporate the size distribution of particles and extended to the suspension network. The model estimates the yield stress as a function of solids loading for various kinds of size distribution and is in reasonable agreement with experimental data when the surface properties of the particle are held constant.