UCL Centre for Nature Inspired Engineering


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.

Granular matter

Past researchers: Kaiqiao Wu, Victor Francia

Collaborators: Heriot-Watt University and Particulate Solid Research Inc (US)

Key Publications:

  1. V. Francia, K. Wu, M.-O. Coppens, 2020, Dynamically structured fluidization: Oscillating the gas flow and other opportunities to intensify gas-solid fluidized bed operation, Chemical Engineering and Processing - Process Intensification, DOI: 10.1016/j.cep.2020.108143 [Link]
  2. K. Wu, V. Francia, M.-O Coppens, 2020, Dynamic viscoplastic granular flows: A persistent challenge in gas-solid fluidization. Powder Technology 365, 172-195. DOI:10.1016/j.powtec.2019.04.053 [Link]
  3. K. Wu, L. de Martín, L. Mazzei and M.-O. Coppens, "Pattern formation in fluidized beds as tool for model validation: a two-fluid modelbased study", Powder Technol., 2016, 295, 35.
  4. M.-O. Coppens,  2012, A nature-inspired approach to reactor and catalysis engineering, Curr. Opin. Chem. Eng., 1, 1. [Link]
  5. J.R. van Ommen, S. Sasic, J. van der Schaaf, S. Gheorghiu, F. Johnsson, and M.-O. Coppens, 2011, Time-series analysis of pressure fluctuation in gas-solid fluidized beds - a review, Int. J. Mult. Flow., 37(5), 403. [Link]
  6. M.-O. Coppens and J.R. van Ommen, 2003, Structuring chaotic fluidized beds, Chem. Eng. J., 96 (1-3), 117. [Link]