Pattern formation in pulsed fluidized beds

Similar to the pattern formation observed on sandy dunes or beaches, induced by the action of wind or waves, experimental measurements on periodically pulsed gas-solid fluidized beds have shown that a periodic gas flow could induce the formation of regular patterns in gas-solid fluidized beds, which normally display chaotic bubble hydrodynamics. Our work has shown that, in quasi-2D beds, bubbles rise in hexagonal configurations with a pitch that seems independent of bed width. In shallow 3D beds, the patterns formed on the surface resemble those observed in vibrated granular media.

We aim to understand the origin of pattern formation in pulsed fluidized beds by combining experiments, theory and multi-scale simulations. We also aim to apply this method to enhance the performance of fluidized bed operations, which are used for drying, coating and chemical production.

Researchers: Lilian de Martín and Kaiqiao Wu.

KEY PUBLICATIONS

  1. K. Wu, L. de Martín, L. Mazzei and M.-O. Coppens,
    "Pattern formation in fluidized beds as a tool for model validation: a two-fluid model based study",
    Powder Technol., 2016, 295, 35.
    [Link]
  2. M.-O. Coppens,
    "A nature-inspired approach to reactor and catalysis engineering"
    ,
    Curr. Opin. Chem. Eng.
    , 2012, 1, 1.
    [Link]
  3. J.R. van Ommen, S. Sasic, J. van der Schaaf, S. Gheorghiu, F. Johnsson, and M.-O. Coppens,
    "Time-series analysis of pressure fluctuations in gas-solid fluidized beds-a review",
    Int. J. Mult. Flow., 2011, 37(5), 403.
    [Link]
  4. M.-O. Coppens and J.R. van Ommen,
    "Structuring chaotic fluidized beds",
    Chem. Eng. J., 2003, 96(1-3), 117.
    [Link]
Pattern formation in pulsed fluidized beds

Collective behaviour and pattern formation of granular matter in deserts (left) and shallow 3D pulsed fluidized beds (right).

Pattern formation in quasi-2D pulsed fluidized beds (a) 2-3-2 alternating pattern and (b) 2-2 alternating pattern.