Modelling of solid particle aggregation dynamics in non-wetting liquid medium

Abstract

The aim of this work is to re-examine and, if need be, to discuss or modify several of the elements of the classical aggregation dynamics models and to adapt them to the case of aggregation in non-wetting media and particularly alumina inclusions aggregation in a turbulent flow of liquid steel. As proved by several experiments and models, solid particles in contact in non-wetting media are linked by gaseous bridges which may pre-exist prior to the aggregate formation. In this paper, the role of these gaseous cavities in the aggregation process is considered. In particular, a complete calculation of the interaction force between hydrophobic surfaces (Bjerkness–Ruckenstein model) is performed. Main aspects of the aggregation dynamics are envisaged in the particular conditions which result from non-wetting. Hydrodynamic interactions between particles are modified by non-wetting, thus the collision efficiency coefficient and the aggregation kernel. The fragmentation kernel of the aggregates, however, is modified to a larger extent and is equal to zero in most cases. Numerical applications are presented in the reference case (alumina particles in liquid steel). A general procedure of use of this model in other non-wetting situations is given too.