Bubble behavior in corrugated-wall bubbling fluidized beds—Experiments and CFD simulations



A new concept to harness bubble dynamics in bubbling fluidization of Geldart D particles was proposed. Various geometrical declinations of a cold-prototype corrugated-wall bubbling fluidized bed were compared at different flow rates (Ug) to conventional flat-wall fluidized bed using high-speed digital image analysis. Hydrodynamic studies were carried out to appraise the effect of triangular-shaped wall corrugation on incipient fluidization, bubble coalescence (size and frequency), bubble rise velocity, and pressure drop. Bubble size and rise velocity in corrugated-wall beds were appreciably lower, at given Ug/Umb, than in flat-wall beds with equal flow cross-sectional areas and initial bed heights. The decrease (increase) in size (frequency) of bubbles during their rise was sustained by their periodic breakups while protruding through the necks between corrugated plates. Euler-Euler transient full three-dimensional computational fluid dynamic simulations helped shape an understanding of the impact of corrugation geometry on lowering the minimum bubbling fluidization and improving gas distribution. © 2011 American Institute of Chemical Engineers AIChE J, 2012