Roman G. Szafran

CFD Modeling of a Spouted-Bed Dryer Hydrodynamics

Abstract A hydrodynamic model based on continuity and conservation equations was used to predict flow behavior in a spouted-bed dryer with a draft tube. The Eulerian-Eulerian multi-fluid modeling approach was applied to predict a gas–solid flow behavior. The model was qualitatively validated and the results of simulations were compared with the experimental data published by various researchers. The model predicts flow behavior well with fluctuations, circulations of phases, and cluster formations in the loading region, as was observed in experiments. The predicted solids circulation rate and the fraction of gas bypassing were close to experimental values published for various systems. The coarse 2D axisymmetric grid, used in simulations, can handle the main process dependencies with a sufficient accuracy for engineering calculations.

Application of CFD Modelling Technique in Engineering Calculations of Three-Phase Flow Hydrodynamics in a Jet-Loop Reactor

The hydrodynamics of a down flow jet-loop reactor with a gas-liquid-solid three-phase system in semi-industrial scale were investigated. The Eulerian-Eulerian modelling approach was applied to predict flow behaviour in the reactor. A commercially available, control-volume-based code FLUENT 6.1 was chosen to carry out the computer simulations. In order to reduce computational times and required system resources, the 2D axisymmetric segregated solver was chosen. The influence of different k-e turbulence models, as well as, different types of meshes on velocity profiles in each phase was analyzed. The unstructured mesh reduces discrepancies on the axis of symmetry caused by the axisymmetric solver and is more accurate. The prediction error of the water circulation rate ratio for a gas-liquid system was only 3.6 % and about 15 % for gas-liquid-solid system. Unfortunately the gas hold-up was not predicted properly.