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Coexistence of solidlike and fluidlike states in a deep gas - fluidized bed / Junwu Wang in Industrial & engineering chemistry research, Vol. 49 N° 11 (Juin 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 11 (Juin 2010) . - pp. 5279–5287 Titre : Coexistence of solidlike and fluidlike states in a deep gas - fluidized bed Type de document : texte imprimé Auteurs : Junwu Wang, Auteur ; M. A. van der Hoef, Auteur Année de publication : 2010 Article en page(s) : pp. 5279–5287 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Gas  fluidized  beds Résumé : Characterizing regime transition in gas-fluidized beds is of fundamental importance for the successful applications of fluidization technology. In this study, we show that a state-of-the-art two-fluid model has the ability to correctly predict the transition from packed bed to fully bubbling fluidized beds. To this end, we have studied a deep gas fluidized bed, in which the process of transition is shown much more clearly (see Figure 1) compared to relatively shallow fluidized beds. Particularly, we show that in the process of regime transition, the solidlike and fluidlike states can coexist. We conclude this on the basis of visual observation, global bed pressure drop signals, local solid volume fraction signals, cross-sectional averaged axial granular temperature profiles, and radial particle velocity profiles. The presence of the coexisting phases can be easily understood from the fact that the gas phase is compressible. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901555p [article] Coexistence of solidlike and fluidlike states in a deep gas - fluidized bed [texte imprimé] / Junwu Wang, Auteur ; M. A. van der Hoef, Auteur . - 2010 . - pp. 5279–5287. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 11 (Juin 2010) . - pp. 5279–5287 Mots-clés : Gas  fluidized  beds Résumé : Characterizing regime transition in gas-fluidized beds is of fundamental importance for the successful applications of fluidization technology. In this study, we show that a state-of-the-art two-fluid model has the ability to correctly predict the transition from packed bed to fully bubbling fluidized beds. To this end, we have studied a deep gas fluidized bed, in which the process of transition is shown much more clearly (see Figure 1) compared to relatively shallow fluidized beds. Particularly, we show that in the process of regime transition, the solidlike and fluidlike states can coexist. We conclude this on the basis of visual observation, global bed pressure drop signals, local solid volume fraction signals, cross-sectional averaged axial granular temperature profiles, and radial particle velocity profiles. The presence of the coexisting phases can be easily understood from the fact that the gas phase is compressible. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901555p

A review of eulerian simulation of geldart a particles in gas-fluidized beds / Junwu Wang in Industrial & engineering chemistry research, Vol. 48 N° 12 (Juin 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 12 (Juin 2009) . - pp. 5567–5577 Titre : A review of eulerian simulation of geldart a particles in gas-fluidized beds Type de document : texte imprimé Auteurs : Junwu Wang, Auteur Année de publication : 2009 Article en page(s) : pp. 5567–5577 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Geldart  particles  Dilute  gas-solid  flow  Eulerian  simulation Résumé : Although great progress has been made in modeling the gas fluidization of Geldart B and D particles and dilute gas−solid flow by standard Eulerian approach, researchers have shown that, because of the limitation of computational resources and the formation of subgrid-scale (SGS) heterogeneous structures, Eulerian model with a suitable SGS model for constitutive law is necessary to simulate the hydrodynamics of large-scale gas-fluidized beds containing Geldart A particles. In this article, a state-of-the-art review of Eulerian modeling of Geldart A particles in gas-fluidized beds is presented. The available methods for establishing SGS models are classified into six categories, that is, empirical correlation method, scaling factor method, structure-based method, modified Syamlal and O’Brien drag correlation method, EMMS-model-based method, and correlative multiscale method. The basic ideas of those methods, as well as their advantages and disadvantages, are reviewed. Finally, directions for future research are indicated. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900247t [article] A review of eulerian simulation of geldart a particles in gas-fluidized beds [texte imprimé] / Junwu Wang, Auteur . - 2009 . - pp. 5567–5577. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 12 (Juin 2009) . - pp. 5567–5577 Mots-clés : Geldart  particles  Dilute  gas-solid  flow  Eulerian  simulation Résumé : Although great progress has been made in modeling the gas fluidization of Geldart B and D particles and dilute gas−solid flow by standard Eulerian approach, researchers have shown that, because of the limitation of computational resources and the formation of subgrid-scale (SGS) heterogeneous structures, Eulerian model with a suitable SGS model for constitutive law is necessary to simulate the hydrodynamics of large-scale gas-fluidized beds containing Geldart A particles. In this article, a state-of-the-art review of Eulerian modeling of Geldart A particles in gas-fluidized beds is presented. The available methods for establishing SGS models are classified into six categories, that is, empirical correlation method, scaling factor method, structure-based method, modified Syamlal and O’Brien drag correlation method, EMMS-model-based method, and correlative multiscale method. The basic ideas of those methods, as well as their advantages and disadvantages, are reviewed. Finally, directions for future research are indicated. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900247t