Gas–solid flow mechanism of spherocylindrical particles with various aspect ratios in spouted bed

Abstract

Spherocylindrical particles encompass elongated spherical particles, such as biomass particles utilized in thermal reactions and capsule pills in the pharmaceutical industry, along with various other particles found in industrial production processes. Understanding the flow behavior of spherocylindrical particles within a spouted bed holds significant practical importance. This study delves into investigating the fluidization characteristics of spherocylindrical particles with varying aspect ratios within a spouted bed. Key parameters studied include particle void fraction, velocity, orientation, and mixing. These were analyzed using the computational fluid dynamics–discrete element method, and the simulation model's accuracy was verified through high-speed photography experiments. The findings revealed distinct void fraction distributions at different locations within the bed. Particles in the higher-bed region exhibited larger void fractions with flatter peaks compared to those in the lower-bed region. Moreover, the correlation between particle aspect ratio and void fraction varied at different heights within the bed. Notably, there was no significant correlation observed between particle aspect ratio and particle velocity. However, the larger the particle aspect ratio/gas velocity, the better the particle mixing quality. Additionally, gas velocity and particle aspect ratio had little effect on particle orientation, but there was a tendency for particle orientation angles to hover around 45°–60° near the wall region.