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-0 - c(U-0/U-mf)(n) U-mf, bubble diameter is modeled by (d) over bar (b) = 0.848G(0.66)D(0.34) and transition velocity is modeled by U-bs/U-mf = 1 + 2.33U(mf)(-0.027)(phi(0.35)c(t)(at) - 1)(h(0)/D)(-0.588). The models are developed using the information obtained from an experimental setup equipped with a dual plane 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.