Experimental Studies on the Wavy Regime in Swirling Fluidized Bed

Swirling Fluidized Bed is one of the noble designs using fluidization principle whereby particles in the bed will experience certain amount of fluid injection, either gas or liquid, generating sufficient reference velocity to create drag from down under the particles in order for fluidization to occur.
Swirling Fluidized Bed is unique as it has an array of distributor blades well arrange at the bed. When gas is injected through the bed setup at certain angles, swirling motion will be created besides fluidizing the particles. Fluidization occurred across the bed results in bed pressure drop and different flow regimes by varying the superficial velocity. Result is obtained through lab experiment by using a blade inclination angle of 10¢ª and blade overlapping angle of 18¢ª setup. Spherical particles with bed weight of 300g to 1000g are used in hydrodynamics study across all regimes with different particle size, particularly 4mm, 5mm and 6mm. This study clearly indicates the effects of bed weight and particle size, particularly in relatively shallow bed. Figure of Bed Pressure Drop vs Reference Velocity is plotted to show the trend and observation is recorded throughout the experiment. Moreover, slugging period and slugging periodicity were recorded to study their unique behavior with increasing of reference velocity.
Higher bed loading result in higher bed pressure drops due to higher bed resistance. Larger size particle show lower bed pressure drop, because interstitial spaces between them are larger, thus lesser resistance. In the slugging width and periodicity studies, crest formation and slug distance travelled are observed where at high reference velocity, crest formed at higher and distance travelled for the slug before disappearing is longer, thus resulting in bigger width and longer time taken. Additionally, starting and end time of wavy regime is recorded based on bed weights and particle size. Lower bed weights required lower reference velocity to achieve slugging and swirling due to lesser inertial forces. Smaller particle size results in lower reference velocity due to bed resistance because smaller particle has large surface area per volume, thus forming smaller interstitial space between particles. More air injected to the bed is capture and utilize them to perform slugging and swirling.