Coarse grid simulation of bed expansion characteristics of industrial-scale gas–solid bubbling fluidized beds

Two-fluid modeling of the hydrodynamics of industrial-scale gas-fluidized beds proves a long-standing challenge for both engineers and scientists. In this study, we suggest a simple method to modify currently available drag correlations to allow for the effect of unresolved sub-grid scale structures, by assuming that the particles inside each computational cell are presented in the form of a two-phase structure. This method would thus make it possible to simulate the hydrodynamics of industrial-scale bubbling fluidized beds of Geldart B and D particles with a coarse computational mesh. It is shown that with the proposed modification of the drag force correlation, the experimentally measured bed expansion characteristics of industrial-scale bubbling fluidized beds can be reasonably predicted at acceptable computational cost. Also the simulation result for the macroscopic solid circulation pattern is in qualitative agreement with the experimental data.