Modelling Of Coagulation Efficiencies InRotating Systems

Abstract

Under the influence of an induced shear and centrifugal field, inter-particle collisions of solid particles in liquids as well as viscous forces result in agglomeration, breakage, and erosion. There is a permanent alteration of the particle size distribution which is described mathematically by the method of population balances. Due to the uniform surface charge of the dispersed particles, a self-induced agglomeration does not take place automatically which means that coagulant agents need to be added to the suspension. The influence of these electrolytes is taken into account by the so-called coagulation efficiency. In the course of this work, two different models are developed describing the collision efficiency locally and in dependence on apparatus geometry, operating conditions, particle combination (species and mass), coagulant agents and material properties. It is shown that in highly rotating systems particle collisions result in small agglomerates although being exposed to large centrifugal forces and shear forces.