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dc.creatorValverde Millán, José Manueles
dc.creatorCastellanos, Antonioes
dc.identifier.citationValverde Millán, J.M. y Castellanos, A. (2009). Extension of Geldart's Diagram to Fluidizable Fine and Ultrafine Particles. En 6th International Conference on the Micromechanics of Granular Media (977-980), Golden, Colorado, (Estados Unidos): American Institute of Physics.
dc.identifier.issn0094-243X (impreso)es
dc.identifier.issn1551-7616 (electrónico)es
dc.description.abstractThe Geldart’s diagram, which was originally based on empirical observations on beds fluidized by air at ambient conditions, has been routinely used to predict the type of gas-fluidization expected for a granular material. However, the Geldart’s diagram, based on particle size and density, is not currently a useful tool to predict the fluidization behaviour of many fine and ultrafine cohesive powders. There are recent reports revealing nonbubbling fluidlike fluidization for some preconditioned fine and ultrafine powders, in contrast with the predicted unfluidizable Geldart C behaviour according to their primary particle size. In this work we present an extension of Geldart’s diagram that rationalizes the type of behaviour observed for this new class of fine and ultrafine powders. In our approach we have extended empirical criteria mostly used in the past to explain the behaviour of liquid-fluidized beds, showing that fluidization, either by liquid or gas, can be understood from a general frame. Our approach to treat gas-fluidized beds of fine cohesive particles considers particle agglomerates, grown to a size limited by the balance between interparticle force and flow shear, as effective low-density particles. In accordance with experimental observations, our diagram predicts that the nonbubbling fluidization regime can be just solidlike for slightly cohesive particles (Geldar A behaviour). When particle size is decreased, we predict the existence of a nonbubbling fluidlike regime for preconditioned powders as seen experimentally. For sufficiently small particles and/or high viscosity gases, the fluidized bed transits directly from the nonbubbling fluidlike regime to elutriation as observed in gas-fluidized beds of nanoparticles, fluidized beds of micrometric particles with high viscosity gas, and liquid-fluidized beds of moderate density large
dc.description.sponsorshipMinisterio de Ciencia y Tecnología (MCYT). España FIS2006-03645es
dc.description.sponsorshipJunta de Andalucía FQM 421es
dc.publisherAmerican Institute of Physicses
dc.relation.ispartof6th International Conference on the Micromechanics of Granular Media (2009), p 977-980
dc.rightsAttribution-NonCommercial-NoDerivatives 4.0 Internacional*
dc.subjectFluidized bedses
dc.subjectDiffusion and aggregationes
dc.subjectGranular flowes
dc.titleExtension of Geldart's Diagram to Fluidizable Fine and Ultrafine Particleses
dc.contributor.affiliationUniversidad de Sevilla. Departamento de Electrónica y Electromagnetismoes
dc.relation.projectIDFQM 421es
dc.eventtitle6th International Conference on the Micromechanics of Granular Mediaes
dc.eventinstitutionGolden, Colorado, (Estados Unidos)es
dc.contributor.funderMinisterio de Ciencia y Tecnología (MCYT). Españaes
dc.contributor.funderJunta de Andalucíaes

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Attribution-NonCommercial-NoDerivatives 4.0 Internacional
Except where otherwise noted, this item's license is described as: Attribution-NonCommercial-NoDerivatives 4.0 Internacional