Models for Predicting Average Bubble Diameter and Volumetric Bubble Flux in Deep Fluidized Beds

The average bubble diameter and volumetric bubble flux give indications about the overall bed expansion in a fluidized bed. As these properties depend on the particle properties and fluidized bed regime, their accurate predictions have been a challenge. A new set of models for predicting the average bubble properties within the bubbling and slugging regimes in a deep fluidized bed is proposed, where bubble flux is modeled by G = U − c( ) U U U a 0 mf 0 mf, bubble diameter is modeled by db̅ = 0.848G D 0.66 0.34 and transition velocity is modeled by = + φ − − − 1 2.33U ( c 1)( ) U U a h mf D 0.027 0.35 t 0.588 bs mf t 0 . he models are developed using the information obtained from an experimental setup equipped with a ualplane electrical capacitance tomography and a porous distributor plate. Although they are empirical, the proposed models are based on the two-phase theory used in describing the bubble flow in a fluidized bed. These models have been validated, and the results show that they can be used to predict the behavior in different regimes at different gas velocities