Dynamic Modelling of Emulsification in High-Pressure Homogenizers

Abstract: Different approaches and sub-models for the modelling of emulsification in a high-pressure homogenizer are reviewed and compared in terms of both practical aspects and how well they describe what is currently known on the emulsification process in general and on high-pressure homogenization in particular. Special effort is devoted to comparing the model developments presented in the appended papers to their alternatives and previous suggestions. A modelling framework for handling the simultaneous fragmentation, coalescence and dynamic adsorption of emulsifier is described and recommended for further studies. A successful emulsification model requires that the hydrodynamics of the high-pressure homogenizer valve can be accurately described. Previous investigations have often used Computational Fluid Dynamics in order to model the flow fields since experiments are scarce. New experimental measurements and comparison to models were therefore performed, resulting in a suggestion for a method to describe the local distribution of turbulent forces in the valve. The integration of hydrodynamic information into the emulsification model can be carried out using different degrees of sophistication. Different strategies are described and compared in the thesis. However, at this time it is not possible to determine what level of sophistication is appropriate under which conditions. It is suggested that further experimental investigations, using the models in order to identify critical conditions, are carried out in order to determine the required complexity of the hydrodynamic-emulsification integration.