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ENCIT 2020
18th Brazilian Congress of Thermal Sciences and Engineering
Determining the granular temperature of gas fluidized beds in narrow tubes
Submission Author:
Karlo Rocha , ES
Co-Authors:
Karlo Rocha, Fernando David Cúñez, Erick de Moraes Franklin
Presenter: Karlo Rocha
doi://10.26678/ABCM.ENCIT2020.CIT20-0302
Abstract
This work reports a numerical study of granular temperature in gas-solid fluidized beds by using an Eulerian- Lagrangian approach (CFD-DEM). The numerical simulations were performed using the open source codes CFDEM, OpenFOAM and LIGGGHTS. The bed was formed in a vertical tube with a diameter of D = 2.5 mm which was filled with glass spheres with a diameter of d = 0.5 mm. The bed consisted of 600 glass beads, and two air flows that correspond to cross-sectional mean velocities of U = 1.05 and U = 1.15 m/s were imposed at the bottom of the tube. The granular temperature was computed by averaging the instantaneous velocities using the concepts of kinetic theory. With these conditions, we observe the formation of alternating high- and low-compactness regions, known as plugs and piston bubbles, and we tracked every single particle and the local volume fraction to obtain the main behavior of the granular temperature in the plugs and bubbles. The values of the granular temperature for the vertical direction, (z direction), is an order of magnitude larger than that for the lateral direction, (x, y directions). The observed anisotropy of the granular temperature is consistent with the conclusions reported in literature.
Keywords
Granular temperature, fluidized bed, gas-solid, plugs, bubbles, CFD-DEM
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