Bubble Dynamics and Particle Orientation in a Binary Fluidized Bed Containing Spherocylinders and Spheres

Fluidized beds containing binary mixtures are widely encountered in biomass utilization processes. On the basis of the computational fluid dynamic-discrete element method and the multisphere model, an integrated model has been developed, validated, and applied to explore the bubble dynamics and particle orientation in a binary fluidized bed with spherocylinders and spheres. The effects of four key parameters (i.e., superficial gas velocity, volume fraction of spherocylinders, particle density, and particle aspect ratio) are systematically explored. The results show that a proper particle aspect ratio can promote the mixing of the two kinds of particles; the addition of spherocylinders could reduce the bubble generation and expansion to some extent; three distinct zones (i.e., central zone, near-wall zone, corner zone) with respective preferential particle orientations are identified; and reducing the gas velocity or increasing the particle density and aspect ratio makes the orientation zones more obvious. All these observations are beneficial for deeply understanding the fluidization in a binary fluidized bed.