Controlling the flow structure in fluidized bed: A CFD-DEM approach

Abstract

The spontaneous production of meso-scale flow features such as bubbles and slugs during gas-solid fluidization is well known. This has direct impact on chemical engineering design issues such as conversion rates during catalyst regeneration. However, controlling the size and frequency of appearance of such bubbles during fluidization is not well-understood. We can control the hydrodynamics of a gas-solid fluidization by pulsing the gas flow with an oscillating component. This provides us with additional tuning parameters to structure the flow within a specific frequency range. This study shows that ordered, hexagonal and zig-zag bubbling patterns can be obtained through this approach. A coupled Discrete Element Method and Computational Fluid Dynamics was used in this study. Our simulation results agree well with experimental observations, thus validating the CFD-DEM approach to capture such phenomena.