Numerical description of flow regime transitions in bubble column reactors by a multiple gas phase model [Review]

摘要

The study of the hydrodynamics of bubble column reactors reveals that three main flow regimes can be distinguished. The present study is an original application of standard numerical multiphase models aiming at a better prediction of the transitions and a better description of these regimes. This approach consists of a two-step calculation with, in a first time, the determination of bubble size distributions using coalescence and break-up laws, and in a second time, the implementation of this distribution in a multiple gas phase Euler-Euler model. Calculations are compared with experimental data: liquid velocities and global gas hold-ups. They were obtained in a cylindrical bubble column in which local or uniform aerations were performed. The comparison shows that our approach allows a good prediction of both flow regime transitions and flow characteristics such as hydrodynamics or turbulence. Furthermore, two bubble-induced turbulence models consisting, respectively, of an added viscosity and of two turbulence source terms added in the k-epsilon transport equations have been compared. (C) 2003 Elsevier Science Ltd. All rights reserved. [References: 22]