Identification and Characterization of Particle Clusters in a Fast Fluidized Bed

Based on a three dimensional visual fast fluidized bed (D=0.1 m, H=3 m), an image processing method was developed to identify and characterize the particle clusters formed by quartz sand particles of mean diameter d_s=0.25 mm, density ρ_p=2650 kg/m³, packing density ρ_pa=1590 kg/m³. Experiment was carried out under the operating condition of superficial gas velocity U_g=4.35 m/s and solid flux G_s=40-70 kg/(m²s). Results indicate that this method is able to identify different types of particle clusters. The size of particle clusters increases with higher calculating location and smaller solid flux, while the number of particle clusters decreases. The falling velocity of particle clusters fluctuates around a certain value about 1m/s.