Vibration augmentation of the solids volume dragged by the wake of a bubble rising in a fluidized bed

Abstract

In a gas fluidized bed, bubbles are mainly responsible for the displacement and mixing of the bed particles, with a direct impact on the bed heat and mass transfer. In this work, the motion of solids in the wake region of an isolated bubble rising in a vibrated fluidized bed is experimentally studied using combined digital image and bubble averaging techniques. The results show that the bubble wake behavior depends on the vibration phase and the bubble position in the bed. Particles penetrate inside the bubble volume during the deceleration of the bed vessel, provoking their characteristic wavy contour. The volume of particles dragged by the bubble wake is affected by the vibration phase due to the interaction of the bubble with the compression and expansion waves travelling inside the vibrated bed. Independently increasing the vibration amplitude or frequency augments the volume of particles dragged by the bubble wake.