Particle-Scale Investigation of the Hydrodynamics and Tube Erosion Property in a Three-Dimensional (3-D) Bubbling Fluidized Bed with Immersed Tubes

Particle-scale study of the gas solid hydrodynamics and the tube erosion in a 3-D bubbling fluidized bed with a tube bundle is conducted in the framework of computational fluid dynamics coupled with the discrete element method. General gas solid flow behaviors are investigated and the time-averaged properties are obtained to explore the influence of tube configuration on the bed hydrodynamics. Moreover, the erosion patterns of immersed tubes locating in the different regions of system are analyzed. The effect of tube configuration on the erosion property is considered. The results show that the presence of the tube bundle limits the bubble diameter and results in homogeneous distribution of the bubble phase in the tube region. Moreover, inserting the tube bundle into the bed reduces the vertical velocity of the solid phase but results in a uniformly horizontal distribution of its concentration. The vertical intensity of solid dispersion is several times that of the lateral one, and the insertion of tube bundle enhances the solid mixing procedure and enlarges the solid dispersion intensities in both the vertical and lateral directions. Different erosion patterns appear on the immersed tubes locating in different regions of the bed. The intrinsic mechanism behind the erosion distribution can be identified from the solid flux distribution near the tubes.