Flow simulation in bubble columns in regard to bubble coalescence and break-up utilizing LES and DEM

Turbulent flow simulations in bubble columns are performed in the Euler-Lagrange approach. In the simulation, a large eddy simulation (LES) model is used as a turbulence model. In addition, bubble contact is considered by using a distinct element model (DEM), and bubble coalescence is taken into consideration as well as bubble break-up by solving a coalescence model based on the contact time and coalescence time. Furthermore, a new bubble-fluid drag model depending on distances among bubbles is introduced in DEM simulations, and it is shown that bubble clusters with high terminal velocities may play an important role for high superficial gas velocities. The present models are next applied to several simulations for bubble columns, and the comparison of the computational results with experimental data shows their effectiveness.