Investigation of Flow Behaviors and Bubble Characteristics of a Pulse Fluidized Bed via CFD Modeling

The bubbling flow in a 2D pulsed fluidized bed is simulated using a developed Eulerian-Eulerian two-fluid modeling approach. Parametric studies are carried on for pulsed inflow of the gas phase with rectangular and sawtooth patterns where three pulsating frequencies of 0.4, 4, and 40 Hz are used. The flow instabilities are observed to develop in the pulsed fluidized bed and the mechanisms leading to the instabilities are discussed. The formation, coalescence, split-up of air bubbles, and their trailing wakes inside the bed are described and discussed in detail. Bubble rising velocity and size are obtained and analyzed. Bed expansion and fluctuation ratio are calculated to evaluate the pulsed fluidization quality. Numerical results improve the understanding of the pulsed fluidization.