CFD‐DEM analysis of the spouted fluidized bed with non‐spherical particles

Abstract

Hydrodynamics of spouted fluidized beds of spherical and elongated sphero‐cylindrical particles with an aspect ratio (AR) of 4 were studied by the CFD‐DEM technique. The multi‐sphere method was adopted to present the sphero‐cylindrical particles. Simulations were validated with the experimental data for both particle types. Bubble equivalent diameter, bubble shape factor, and leakage fraction were obtained in the simulations. Time‐averaged particle velocity and porosity profiles, solids circulation rate, particle exchange distribution at the spout‐annulus interface, were investigated in the beds filled with spherical and sphero‐cylindrical particles at gas mass flow rates of 0.005, 0.007, and 0.009 kg/s. The equivalent bubble diameter was found to be lower for spherical particles compared to sphero‐cylindrical particles. The leakage fraction of the bubble was lower for sphero‐cylindrical particles. Solid circulation rate and spout diameter were larger for the bed of spherical particles. A higher probability of particles transition into the spout was observed for spherical particles. Investigating the orientation showed that sphero‐cylindrical particles tend to orient almost vertically against the gas flow in the spout region, which lowers the exerted drag force, whereas the particles align nearly horizontally in the annulus region. The results revealed that the CFD‐DEM approach is a promising method for investigating the fluid and both spherical and non‐spherical particle behaviours in spouted fluidized beds.

Numerical Studies on Particle Dynamics in a Spouted Bed

“…An open-source CFDEM , has been used to perform the coupled simulations reported here. The software has also been used in earlier studies − for simulating gas-particle flow. In the present simulations, the governing equations have been solved using a finite volume method.…”

A comprehensive comparison of Two-Fluid Model, Discrete Element Method and experiments for the simulation of single- and multiple-spout fluidized beds

“…Due to limitations of "resolved CFD-DEM" in modelling a high number of particles and large computational domains, "unresolved CFD-DEM" approach, where computational cells are larger than particle diameter are used. Although this approach neglects flow around particles, particles are fully resolved in the DEM section and the computational time is considerably lower; thus "unre-solved CFD-DEM" approach is preferable in modelling of largescale systems of particle-laden flows (Golshan et al, 2017;Esgandari et al, 2021).…”

CFD-DEM simulation of heat transfer in spout-fluid beds

“…Obtaining a thorough understanding of particle behavior, hydrodynamics, and heat and mass transfer mechanisms is essential to the successful operation and scale up of these gas-solid contactors. These complex systems have been studied using a variety of techniques [1][2][3][4]. In spite of the extensive information that has been obtained through experimental studies regarding spoutfluid beds, measurements are limited in understanding the details of heat transfer due to the complex interactions between gas, particles, and walls.…”