LES modelling of multiphase turbulent flows in bubble columns using an adaptive-mesh finite element method

Abstract

Turbulence drives mixing in multiphase flow reactors such as bubble columns, which are widely used in chemical and bioprocess industry. The understanding of turbulence in these two-phase gas–liquid columns is critical to understanding the dynamics of these flows for better equipment design. The present work focuses on the finite-element computational fluid dynamics modelling of turbulent flows in bubble columns with the use of the large eddy simulation (LES) model, which allows for resolving the dynamics of turbulent flows such as the oscillating plume. Two-dimensional fixed- and (optimized) adaptive-mesh simulations were performed and the results are validated against published experiments. The global flow parameters, including time-averaged gas holdup and plume oscillation period, showed good agreement with experiments. At a superficial gas velocity of 0.6cms−1, a plume oscillation period of 6.2s was predicted with a validation error of 9.6% and a gas holdup of 1.4% with a validation error of 7.5%. The novelty of the work lies in the use of a finite element framework with adaptive mesh refinement and the LES turbulence model to simulate bubble column reactors.