Numerical investigation of pulsed fluidized bed using CFD-DEM: Insights on the dynamics.

Computational Fluid Dynamics and Discrete Element Method are used to study the dynamics of a pseudo-2D pulsed fluidized bed, consisting of Geldart B particles. The focus is on the response of the system to variations in the mean gas velocity, V M , and the amplitude of oscillations, V A , at an imposed frequency of 3.5 Hz. Distinctive flow patterns are mapped out based on observation of simulations, pressure fluctuations and bubble granular temperature profiles. A regime transition is observed when V A is varied under constant V M. Such transition is underlined by: a peak in time-averaged pressure drop and coordination number; a change in the dynamics of the solid phase; an increase in velocity of the void fronts traversing the particle bed; and a decrease in minimum average height attained by the solid phase. This is related to the suppression of void layers at higher V A , occurring more easily at lower V M. Unlabelled Image • Regime transition is induced by amplitude of oscillation. • Flow patterns are altered by mean superficial velocity and amplitude of oscillation. • Shift in solid phase dynamics is captured by coordination number. • Stronger collapse of void layers induces longer periods of lower coordination number. [ABSTRACT FROM AUTHOR]