UCL Centre for Nature Inspired Engineering


Dynamic Structuring of Fluidised Beds: Our extensive review is out!

16 December 2020

Sand dune waves

Victor Francia, Kaiqiao Wu and Marc-Olivier Coppens review various approaches to structure gas-solid fluidized beds in their latest article in Chemical Engineering and Processing - Process Intensification, in a Virtual Special Issue on process intensification in fluidization, triggered by the Fluidization XVI conference in Guilin (China) last year.

Granular media are dissipative systems, which develop complex spatiotemporal patterns when excited by an oscillating energy source.

This paper discusses how such perturbations initiate surface patterns and how these could propagate into a macroscopically organised flow. This phenomenon is called dynamically structured fluidisation. Vibrated shallow granular layers and shallow gas-pulsed beds form ordered surface waves – similar to patterns on dunes and beaches. In deep, pulsed beds the hydrodynamics are more complex, as surface waves transition into a three-dimensionally ordered bubbling flow. In this dynamically structured state, bubbles organise into highly predictable, scalable sub-harmonic, triangular lattices, allowing for an unprecedented level of control.

The resulting beds sit between fixed and fluidised beds, offering new opportunities for process intensification, due to less macromixing than traditional fluidisation, but a higher level of control through micromixing. This informs new intensified designs for processes that are highly exothermic, involve particle formation, thermally sensitive or high-value materials. The tremendous industrial potential has triggered a recent patent application as well.


Victor Francia is a former postdoc at UCL CNIE, and is now Assistant Professor at Heriot Watt University.

Kaiqiao Wu obtained his PhD at UCL CNIE, and is now postdoc at TU Delft

Marc-Olivier Coppens is the Director of the UCL CNIE

Read the article here: https://doi.org/10.1016/j.cep.2020.108143