Insights in hydrodynamics of bubbling fluidized beds at elevated pressure by DEM-CFD approach

A numerical simulation was conducted to study the effect of pressure on bubble dynamics in a gas-solid fluidized bed The gas flow was modeled using the continuum theory and the solid phase by the discrete element method (DEM) To validate the simulation results calculated local pressure fluctuations were compared with corresponding experimental data of 1-mm polyethylene particles It was shown that the model successfully predicts the hydrodynamic features of the fluidized bed as observed in the experiments Influence of pressure on bubble rise characteristics such as bubble rise path bubble stability average bubbles diameter and bubble velocity through the bed was investigated The simulation results are in conformity with current hydrodynamic theories and concepts for fluidized beds at high pressures The results show further that elevated pressure reduces bubble growth velocity and stability and enhances bubble gyration through the bed leading to change in bed flow structure (C) 2010 Chinese Society of Particuology and Institute of Process Engineering Chinese Academy of Sciences Published by Elsevier B V All rights reserved