Coherent structures and bubble-particle velocity in 2-D fluidized beds

Abstract

This work presents an experimental study to characterize ascending bubbles and granular velocity in the dense phase of a 2-D fluidized bed. Three different non-intrusive techniques based on images obtained with a high speed camera are developed, and applied to the images. First the bubble paths are characterized with time-average concentration maps and the bubble velocities are obtained, using a tracking algorithm over the mass centers of the bubbles. Finally, a PIV (particle image velocimetry) method is used to characterize the particle velocity vectors. This procedure is repeated for different bed aspect ratios, and different superficial gas velocities. This study analyzes the superficial gas velocity influence on the bed behavior, and how the bubble path configuration depends on the bed aspect ratio. The PIV measurements give us information on the location of the recirculation regions and the influence of the superficial gas velocity.