Influences of the fluidizing and spouting pulsation on particle motion in spout-fluid beds

Abstract

Effects of variable airflow on particle motion in spout-fluid beds are studied. Computational fluid dynamics using Navier–Stokes equations for the gas phase coupled with the discrete element method using Newton’s laws for the solid phase have been employed. Results indicate that increasing the fluidizing velocity diminishes dead zones and increases both the total height of the bed and the traversed distance by particles in the steady spout-fluid bed. In pulsed airflows, two configurations are investigated, namely, the spouted pulsed-fluidized bed with pulsed flow of the fluidizing velocity, and the pulsed-spouted fluidized bed with pulsed flow of the spouting velocity. The positive effect of pulsation on particle motion is shown and the effects of parameters, such as amplitude and frequency, on the dynamics of the bed are investigated in each configuration. An increase of up to 19% in traversed distance is found for the range studied, which suggests flow pulsation as a promising technique for increasing particle mixing in spout-fluid beds.