Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
GAS-SOLID 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.COBEM2021.COB2021-1377
Abstract
Fluidized beds are extensively used in chemical, pharmaceutical, and mineral industries. For instance, they can be found in a wide range of applications such as coal burning, coal gasification, organic synthesis, mineral processing, and incineration of waste due to their ability to transfer high mass and energy quantities. Over the last years, the increasing use of biomass materials in industrial applications has revived our interest in using fluidized beds. In the case of gas-solid fluidized beds in narrow tubes, instabilities usually appear in the form of granular plugs and bubbles characterized by regions of high and low concentration of particles, respectively. These patterns emerge due to the high confinement effects that come from the low ratio between the sizes of the tube and particles (D/d<10). In this study, the behavior of gas-solid fluidized beds in narrow tubes is investigated numerically. The beds were formed in a vertical tube with an internal diameter of D = 3 mm and were filled with glass spheres with a diameter of d = 0.5 mm. We used two arrangements of beds consisting of 400 and 600 glass beads. Then we imposed three airflow rates at the inlet of the tube that correspond to cross-sectional mean velocities of U = 1.4Umf, U = 1.8Umf, and U = 2Umf, where Umf is the minimum fluidization velocity. Under these conditions, we observed the formation of granular plugs and bubbles that propagate with characteristic lengths and celerities. The numerical simulations were performed using an Eulerian-Lagrangian approach (CFD-DEM), where we used the open-source codes CFDEM, OpenFOAM, and LIGGGHTS. From our results, we tracked every single particle and the local volume fraction of each bed over time to obtain the primary behavior of this problem. Also, we computed and then analyzed the evolution of the granular temperature and the collisions of the particles. Our results bring new contributions on the role of gas-solid fluidized beds in narrow tubes.
Keywords
fluidized bed, gas-solid, Granular temperature, plugs, bubbles, CFD-DEM, narrow tubes.
