Mesoscale modeling of emulsification in rotor-stator devices

Droplet size distribution represents one of the key parameters of emulsification products and emulsification efficiency. While there is a large number of computational fluid dynamics and population balance model (CFD-PBM) simulation for droplet size distribution in various emulsification devices, fitting parameters or empirical correlations were always involved to generate the reasonable simulation. In this study, we applied the Energy-Minimization Multi-scale (EMMS) approach for the liquid-liquid flow in rotor-stator (RS) mixing devices. The so-called mesoscale energy dissipation for droplet breakage was derived to close the population balance equations through a breakage rate corrector. The correction factor was then integrated into the fully-coupled CFD-PBM simulation for a surfactant-free MCT-oil/water system. Compared to the original Alopaeus breakage model or the combination of Alopaeus model and Prince coalescence model, this new model could greatly improve the prediction of droplet size distribution, Sauter mean diameter, median diameter and span of size distribution for both the dilute and the dense systems of dispersed oil phase.