Measuring fluidization behaviors of monodisperse non-spherical particles and binary mixtures of spheres with cylinders

Abstract

Understanding the fluidization behavior of monodisperse non-spherical particles and binary mixtures containing non-spherical particles is essential for better designing and optimizing fluidized bed reactors. This study experimentally investigated the effect of particle shapes on the fluidization behavior of monodispersed particles and binary particles in a rectangular bubbling fluidized bed. The experimental measurements include the total pressure drop, sectional pressure drops, mixing, and segregation. A machine learning-aided image processing method was developed to segment different particles from the background in binary fluidization and analyze particle dynamics, such as particle height distribution and non-spherical particle orientation distribution. The experimental results show that the minimum fluidization velocity decreases with a decrease in sphericity ranging from 0.63 to 1. Higher expansion height is observed for non-spherical particles than for spherical particles. Cylindrical particles disperse the most when the orientation angles (the angle between axial and horizontal directions) are ± 75°. The Lacey mixing index of sphere and cylinder mixtures decreases with the increase of the aspect ratio of cylindrical particles ranging from 1 to 5, corresponding to well and poor mixing states. The experimental results serve as benchmark data to validate computational fluid dynamics models.