Computational fluid dynamics simulation of the heterogeneous regime in a large-scale bubble column
Nicolò Varallo, Giorgio Besagni, Riccardo Mereu
Abstract
Bubble columns are used in many industrial applications, but the complex fluid dynamics phenomena has limited their design and optimization processes. Computational Fluid Dynamics (CFD) is a promising tool to investigate the complex multi-scale flow physics characterising multiphase reactors. In this work, a CFD Eulerian-Eulerian modelling approach is developed to describe the hydrodynamics of a large-scale bubble column operated over a wide range of superficial gas velocities (0.0188 – 0.20 m/s). Available experimental results were used for the model validation. A drag law for oblate bubbles was considered and coupled with a drag modification function to include the effects of bubble-bubble interactions. The numerical approach was tested considering a mono-dispersed approximation and including coalescence and breakup by using a Population Balance Model (PBM). The role played by the lift force was investigated and, for the reactor configuration considered, it turned out to be essential in the description of the local flow properties.