Molecules as building blocks for a CFD-PBE model to describe the effect of fluid dynamics on nanoparticle formation

Recently research efforts have focused on the effect of fluid dynamics on particle formation processes, by using special mixing devices, that allow to perform controlled experiments, and complex models, that allow to quantify its influence on the final particle size. The standard modelling approach consists in considering three different steps: nucleation, molecular growth and aggregation. This is usually done by simulating the process with a population balance equation (PBE) coupled with computational fluid dynamics (CFD), in which these three different steps are considered separately. The PBE is often written using as internal coordinate the actual particle size or volume; here, we propose a new modelling strategy that overcomes the concepts of nucleation and molecular growth, by using as internal coordinate the number of molecules which aggregate, or self-assemble, together forming a nanoparticle. The novel modelling approach is therefore defined as a purely-aggregative model.