Flow structure formation in high-velocity gas-fluidized beds

Jie Li, J.A.M. Kuipers

    Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

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    Abstract

    The occurrence of heterogeneous flow structures in gas-particle flows seriously affects the gas-solid contacting and transport processes in high-velocity fluidized beds. A computational study, using a discrete particle method based on Molecular Dynamics techniques, has been carried out to explore the mechanisms underlying the cluster and the core/annulus structure formation. Based on energy budget analysis including work done by the drag force, kinetic energy, rotational energy, potential energy, and energy dissipation due to particle-particle and particle-wall collisions, the role of 1) gas-solid interaction and 2) inelastic collisions between the particles are elucidated. It is concluded that the competition between gas-solid interaction and particle-particle interaction determines the pattern formation in highvelocity gas-solid flows: if the gas-solid interaction (drag) dominates, a uniform flow structure prevails. Otherwise, a heterogeneous pattern exists, which could be induced by both particleparticle collisions and gas-solid interaction. Although both factors could cause the flow instability, the drag force is demonstrated to be the necessary condition to trigger the heterogeneous flow structure formation.
    Original languageEnglish
    Title of host publicationCirculating Fluidezed Bed Technology VII
    Subtitle of host publicationProceedings of the 7th International Conference on Circulating Fluidezed Beds held at Niagara Falls, Ontario, Canada, May 5-8, 2002
    EditorsJohn R. Grace, Jingxu Zhu, Hugo de Lasa
    Place of PublicationOttawa
    PublisherCanadian Society for Chemical Engineering
    Pages419-426
    Number of pages8
    Publication statusPublished - 2002
    Event7th International Conference on Circulating Fluidized Beds, CFB-VII 2002 - Niagara Falls, Canada
    Duration: 5 May 20027 May 2002
    Conference number: 7

    Conference

    Conference7th International Conference on Circulating Fluidized Beds, CFB-VII 2002
    Abbreviated titleCFB-VII
    CountryCanada
    CityNiagara Falls
    Period5/05/027/05/02

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