On time-averaged CFD modeling of circulating fluidized beds

Veikko Taivassalo, Sirpa Kallio, Juho Peltola

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


    CFD simulations of single-phase flows are regularly performed as steady-state utilizing closure models of varying complexity. On the contrary, multiphase flows are usually computed as time dependent. Multiphase simulations commonly require a small time step and a fine mesh resulting in costly and time-consuming computations. In case of large industrial circulating fluidized beds (CFB), steady-state CFD modeling would be an attractive alternative for the transient simulations if reliable closure models for the time-averaged transport equations were available. The multiphase closure models developed for time-dependent CFB computations are not as such applicable to the steady-state approach. For instance, the fraction of the momentum transfer expressed by the velocities is significantly smaller in the steady-state models than in the transient ones. Therefore, the steady-state simulations rely more on the closure relations and especially on the models for inter-phase momentum transfer and for the Reynolds stress terms. Several attempts to develop closure models for coarse-mesh and steady-state simulations have been presented in the literature. In this paper, a novel steady-state simulation approach for a CFB process and a corresponding CFD model are introduced. A successful steady-state simulation for a test case is presented. Compared to the time-dependent simulations, the computing time is reduced by a factor of an order of 1000.
    Original languageEnglish
    Title of host publicationProceedings
    Subtitle of host publication12th International Conference on Multiphase flow in Industrial Plants, MFIP 2012
    Place of PublicationNapoli, Italy
    Number of pages7
    Publication statusPublished - 2011
    MoE publication typeA4 Article in a conference publication
    Event12th International Conference on Multiphase flow in Industrial Plants, MFIP12 - Ischia, Italy
    Duration: 21 Sept 201123 Sept 2011


    Conference12th International Conference on Multiphase flow in Industrial Plants, MFIP12
    Abbreviated titleMFIP 2012


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