Home > Research at LGC > GIMD - Interface and Particle Interaction Engineering > Research topics > Theme 4 : Hydrodynamics and transport

Theme 4 : Hydrodynamics and transport

Contact : Micheline ABBAS

This theme focuses on the development of experimental and complementary numerical techniques to determine how hydrodynamic interactions, collective effects and multi-phase coupling control transport properties (agitation, viscosity, dispersion) and transport of properties (particle size and shape) in processes occurring in heterogeneous media?

Visualization of a dislocation in a flow of concentrated emulsion.

From transport properties…

- Transport studies in emulsions with a particle Reynolds number <<1 have shown that the concept of effective medium was relevant up to a volume fraction of 0.6, in fully laminar or turbulent regime. In contrast, for particle suspensions with a finite particle Reynolds number in a channel, simulations have shown that the laminar turbulent transition is the result of an interaction between the migration of particles towards the walls, interactions between particles and the rotational structures of the fluctuating flow.
- For the first time, direct numerical simulation (fictitious domain with penalization) of a 3D liquid fluidized bed was performed for the same geometry and the same flow parameters as those used in an experimental study also carried out at the LGC. The simulation/experiment confrontation for the statistical quantities related to the transport of the two phases validated the method and opened up a broad field of investigations in partnership with I2M (Bordeaux) and IMFT (project with FERMAT support).
- Direct numerical simulation has been used not only to predict the flow of suspensions and of the beads in a stirred-medium grinding mill but also to determine the parameters that control the energy efficiency of the process.

Formation of a plume of bacterial filaments in a model porous medium.

… to the transport of properties

- While studying the filtration of colloidal suspensions using the techniques of micro- fluidics, microseparators revealed the occurrence of different clogging regimes (absence of deposit, formation of dendrites or arches leading to deposits) depending on the conditions of filtration. Stability of particles to aggregation, the filtration rate and the concentration of the suspension, for instance, were taken into account.
- Numerical simulations confirmed the direct impact of the colloidal interactions and hydrodynamics on the formation of arches and the growth of the deposit at the pore entrance. These studies were carried out in collaboration with LM2P2, Suez Environnement and IMFT.
- The mechanisms underlying the flocculation of particle suspensions was analyzed in the turbulent regime in a Taylor-Couette reactor in collaboration with LISBP. It was observed that the size and shape of the flocs depended on the smallest scales of the turbulence and the stirring intensity. This type of study identified the morphological descriptors required for finer modeling of the process via the aggregation or break-up kernels in population balance equations, resolved by the quadrature based on moments methods (QMOM and DQMOM). These studies continue in collaboration with the Mathematics Institute of Toulouse.

Simulation of stratification of a suspension in a channel flow.