Experimental analysis of bubble size distributions in 2D gas fluidized beds

The present work focuses on the development of a novel statistical approach for the analysis of the behavior of a 2D fluidized bed operating under bubbling and slugging conditions. Experimental data were collected by means of a purposely built lab-scale 2D fluidized bed and an original digital image analysis technique (DIAT), allowing the acquisition of a number of data sufficient to perform a statistical analysis of bubble dynamics. In particular, measurements of bubble size distributions (BSD) along the bed were performed. The analysis allowed to characterize the shape of BSD for different particle systems and fluidization gas velocities; interestingly a bimodal shape of BSD is observed, likely due to the simultaneous presence of coalescence and splitting phenomena. Linear combination of two Gamma distributions was used to describe the data. Also bubble size distributions weighed on bubble area were computed, and for all cases a characteristic negatively skewed distribution shape was found. Preliminary assessment of available data allowed to point out the effectiveness of the new approach proposed for a more in-depth description of bubble dynamics in 2D gas fluidized beds. (C) 2010 Elsevier Ltd. All rights reserved.