Tuesday, November 10, 2015
Ballroom F (Salt Palace Convention Center)
The gas-solid flow in a bubbling bed was simulated by the combined approach of Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM). The influence of particles collision parameters of particle-particle elasticity coefficient and restitution coefficient on particles movement and bubbles characteristics were investigated. The results demonstrate that the elasticity coefficient has some effects on the bed height, average height and average temperature of the granular, as well as bubbles behavior. The average height and average temperature of granular increases with increasing the elasticity coefficient, while the number of small bubbles decreases. A big restitution coefficient leads to a high bed height and average granular height, a low granular temperature, as well as a low frequency of bubbles formation. The particle-particle elasticity coefficient and restitution coefficient was valued as 1000 and 0.9 for the system presented in this paper. The flow pattern, bubbles behavior, and the solid volume fraction in bubbling beds at different gas velocities (1.25umf, 1.5umf and 2.0umf, respectively) predicted by the DEM approach all are in good agreement with experimental data, which indicates the capability of DEM approach in describing the hydrodynamics of heterogeneous gas-solid flow in bubbling fluidized beds provided that the elasticity coefficient and the restitution coefficient were appropriately specified.