Modelling of fluid dynamics and mixing in shallow bubble column reactors: influence of sparger design

Fluid dynamics and mixing in shallow bubble column reactors is controlled by sparger configuration. In this paper, we evaluate the applicability of using computational fluid dynamics (CFD)-based models to simulate transient fluid dynamics and mixing in shallow bubble columns. A two-fluid model along with the standard k-epsilon turbulence model was used to simulate flow generated by gas sparged through two different spargers in a bubble column with height to diameter ratio of 2, Different mixing time definitions were evaluated using the CFD-based simulations of mixing of passive tracer. The role of unsteady fluid dynamics and implications of possible simplifications in the geometry of bubble columns for simulating mixing in bubble columns were studied. The simulated results were analysed with reference to the experimental data of Haque et.al. (1986. Chemical Engineering Journal, 33, 63-69). The presented results and analysis will be useful to extend the application of CFD models for screening alternative sparger designs. (C) 2001 Elsevier Science Ltd. All rights reserved.