Flow Structure of the Solids in a 3-D Gas-Liquid-Solid Fluidized Bed
Local and macroscopic solids flow structure and kinematics in a 3-D gas-liquid-solid fluidized bed were studied using a noninvasive radioactiue-particle tracking (RPT) technique. Based on the multisite detection of γ radiations emitted from a single radiolabeled tracer particle freely moving in the...
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00011541_v42_n9_p2439_Larachi |
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todo:paper_00011541_v42_n9_p2439_Larachi2023-10-03T13:51:12Z Flow Structure of the Solids in a 3-D Gas-Liquid-Solid Fluidized Bed Larachi, F. Cassanello, M. Chaouki, J. Guy, C. Bubbles (in fluids) Fluidized beds Gamma rays Kinematics Physical properties Radioactive tracers Three dimensional Trajectories Turbulence Velocity measurement Vortex flow Wakes Bubble wakes Flow structure Particle velocities Radioactive particle tracking Turbulence intensities Flow of solids flow fluidized beds Local and macroscopic solids flow structure and kinematics in a 3-D gas-liquid-solid fluidized bed were studied using a noninvasive radioactiue-particle tracking (RPT) technique. Based on the multisite detection of γ radiations emitted from a single radiolabeled tracer particle freely moving in the fluidized bed, RPT permitted to obtain fast sampling of 3-D trajectories of the tracer, whose physical properties were similar to those of the solids inventory. These trajectories showed the detailed motion sequences of the solid particles as entrained in the bubble wakes, fluctuating randomly or sinking deterministically in the liquid-solid emulsion. Based on measurements done in the vortical-spiral flow regime, the dynamic solids flow structure inside a three-phase fluidized bed can be viewed as a three-zone core-annulus-annulus structure; (1) a central fast-bubble flow region with the particles swirling upward; (2) a vortical flow region around the velocity inversion point with the particles momentarily captured in emulsion vortices; and (3) a relatively bubble-free descending flow region where the particles spiral down between the velocity inversion point and vessel walls. Our solids flow structure of dense fluidized beds are similar to the flow structure of liquid and/or solid in lean fluidized beds (observed through laser sheeting imaging). Measured distributions of local ensemble-averaged particle velocities and turbulence intensities were consistent with the existence of a toroidal recirculatory solids flow pattern in the bed. Measured mean circumferential ensemble-averaged radial velocity was essentially zero throughout most of the bed. The solids flow turbulence field was nonisotropic, as radial turbulence intensities were generally lower than longitudinal turbulence intensities. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00011541_v42_n9_p2439_Larachi |
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Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Bubbles (in fluids) Fluidized beds Gamma rays Kinematics Physical properties Radioactive tracers Three dimensional Trajectories Turbulence Velocity measurement Vortex flow Wakes Bubble wakes Flow structure Particle velocities Radioactive particle tracking Turbulence intensities Flow of solids flow fluidized beds |
| spellingShingle |
Bubbles (in fluids) Fluidized beds Gamma rays Kinematics Physical properties Radioactive tracers Three dimensional Trajectories Turbulence Velocity measurement Vortex flow Wakes Bubble wakes Flow structure Particle velocities Radioactive particle tracking Turbulence intensities Flow of solids flow fluidized beds Larachi, F. Cassanello, M. Chaouki, J. Guy, C. Flow Structure of the Solids in a 3-D Gas-Liquid-Solid Fluidized Bed |
| topic_facet |
Bubbles (in fluids) Fluidized beds Gamma rays Kinematics Physical properties Radioactive tracers Three dimensional Trajectories Turbulence Velocity measurement Vortex flow Wakes Bubble wakes Flow structure Particle velocities Radioactive particle tracking Turbulence intensities Flow of solids flow fluidized beds |
| description |
Local and macroscopic solids flow structure and kinematics in a 3-D gas-liquid-solid fluidized bed were studied using a noninvasive radioactiue-particle tracking (RPT) technique. Based on the multisite detection of γ radiations emitted from a single radiolabeled tracer particle freely moving in the fluidized bed, RPT permitted to obtain fast sampling of 3-D trajectories of the tracer, whose physical properties were similar to those of the solids inventory. These trajectories showed the detailed motion sequences of the solid particles as entrained in the bubble wakes, fluctuating randomly or sinking deterministically in the liquid-solid emulsion. Based on measurements done in the vortical-spiral flow regime, the dynamic solids flow structure inside a three-phase fluidized bed can be viewed as a three-zone core-annulus-annulus structure; (1) a central fast-bubble flow region with the particles swirling upward; (2) a vortical flow region around the velocity inversion point with the particles momentarily captured in emulsion vortices; and (3) a relatively bubble-free descending flow region where the particles spiral down between the velocity inversion point and vessel walls. Our solids flow structure of dense fluidized beds are similar to the flow structure of liquid and/or solid in lean fluidized beds (observed through laser sheeting imaging). Measured distributions of local ensemble-averaged particle velocities and turbulence intensities were consistent with the existence of a toroidal recirculatory solids flow pattern in the bed. Measured mean circumferential ensemble-averaged radial velocity was essentially zero throughout most of the bed. The solids flow turbulence field was nonisotropic, as radial turbulence intensities were generally lower than longitudinal turbulence intensities. |
| format |
JOUR |
| author |
Larachi, F. Cassanello, M. Chaouki, J. Guy, C. |
| author_facet |
Larachi, F. Cassanello, M. Chaouki, J. Guy, C. |
| author_sort |
Larachi, F. |
| title |
Flow Structure of the Solids in a 3-D Gas-Liquid-Solid Fluidized Bed |
| title_short |
Flow Structure of the Solids in a 3-D Gas-Liquid-Solid Fluidized Bed |
| title_full |
Flow Structure of the Solids in a 3-D Gas-Liquid-Solid Fluidized Bed |
| title_fullStr |
Flow Structure of the Solids in a 3-D Gas-Liquid-Solid Fluidized Bed |
| title_full_unstemmed |
Flow Structure of the Solids in a 3-D Gas-Liquid-Solid Fluidized Bed |
| title_sort |
flow structure of the solids in a 3-d gas-liquid-solid fluidized bed |
| url |
http://hdl.handle.net/20.500.12110/paper_00011541_v42_n9_p2439_Larachi |
| work_keys_str_mv |
AT larachif flowstructureofthesolidsina3dgasliquidsolidfluidizedbed AT cassanellom flowstructureofthesolidsina3dgasliquidsolidfluidizedbed AT chaoukij flowstructureofthesolidsina3dgasliquidsolidfluidizedbed AT guyc flowstructureofthesolidsina3dgasliquidsolidfluidizedbed |
| _version_ |
1807322681871171584 |