Application of Eulerian-Eulerian-Lagrangian hybrid model to simulate liquid-liquid drop size distribution in stirred tank reactors

Abstract

In the current work, we present an Eulerian-Eulerian-Lagrangian hybrid model for the simulation of liquid-liquid emulsions in agitated tanks. The main idea of such a modeling strategy is to use a combination of a Lagrangian discrete phase model (DPM) and an Eulerian-Eulerian two-fluid model (TFM) to take advantage of the benefits of those two formulations. Furthermore, droplet breakup can be efficiently evaluated for each DPM trajectory. Here, we propose a novel material property dependent breakup model, where breakup is triggered by the local shear. An implicit approach for coalescence is examined in combination with droplet breakup. The presented method is implemented by an user-defined function in the commercial CFD code ANSYS FLUENT. Finally, the models are validated for several stirred tank configurations. The resulting droplet size distribution (DSD) shows fairly good agreement with the experimentally determined DSDs.