Hydrodynamics and gas-mixing associated with bubble bursting at the surface of a fluidized bed

Gas-mixing phenomena play a significant role in fluidized bed combustion of solid fuels. In particular, the extent of mixing between segregated gaseous pockets/streams in the splashing zone or in the upper freeboard is relevant in combustion of high-volatile solid fuels (biomass, RDF, etc.). The present work aims at investigating gas-mixing in bubbling fluidized bed with specific reference to the splashing zone. A laser assisted imaging technique has been used to characterize the hydrodynamic patterns associated with the bursting of isolated bubbles at the surface of an incipiently fluidized bed. Parameters defining the general hydrodynamic behaviour and macromixing of the bubble-generated gas pockets with the mainstream gas were assessed.