Intensification of mixing in complex fluids using fractal oscillating grid turbulence – I-FrOG

I-FrOG aims at proposing a ground-breaking concept of turbulence generation by fractal oscillating grids, capable of enhancing mixing in bio-fluids with complex rheology, with limited imposed shear-stress and degradation. In the context of ecological and energy transitions, the development of technologies combining bio sequestration and production of micro-organisms show a great potential for circular economy in chemical/pharmaceutical applications. Process efficiency depends on the ability of the medium to capture and mix compounds necessary for microorganisms to grow. Mastering their intensification remains, to this day, challenging, since agitation is at the same time required but may also damage the microorganisms, and since mixing performances are sensitive to the complex and process evolving non-Newtonian biological fluid rheology. Oscillating grids show promising potential for lifting such locks, based on their ability to create turbulence at low mean shear, an ability that could be further improved by the use of fractal grids. In this project, an experimental characterisation of the flow induced by oscillating fractal grids, so far unexplored, will be performed in simple and complex model fluids, using state of the art optical methods, and completed by numerical modelling. Applicability to microalgae culture in photobioreactors will be investigated, and optimal mixing and process intensification strategies using oscillating fractal grids will be identified.