The investigation and modeling of the evaporation rates and particle formation for spray drying processes is usually performed on the scale of single droplet drying experiments. Especially the solidification processes of suspension drops and the resulting evaporation rates in the second drying stages are not yet fully understood. In an extensive parameter study, the drying mechanisms in an insulated acoustic levitator are evaluated at varying gas temperatures, relative humidities and drop compositions. Based on design of experiments, a methodical approach for the empirical model development of the drying rates in the first and second drying stages is presented. It is shown, that the drop deformation has to be considered when modeling the evaporation. A qualitative analysis of the resulting particle morphologies is given and a dynamic model for the complete single droplet drying experiment is presented.
