Topic 1: Flows of particles through a porous medium
The experimental device that permits to study the flow of small particles through a porous medium uses a Plexiglas cell to support the porous medium. This medium is made of a packing of glass beads of diameter D. A piezoelectric scale is placed under the porous structure. It permits to measure precisely time evolution of material mass collected at the output of the porous medium. We also place a collecting box, which lets us determine exit positions of particles. The particles injected into the porous structure are beads of diameter d. This diameter is chosen in such way that the size ratio D/d is far from the geometrical trapping threshold. More information about this geometrical threshold can be found on this page. The particles are initially contained in a bead dispenser with a vertical opening hatch. The dispenser is made of concentric cubes to make the launch as compact as possible whatever the number of particles is. The opening of the dispenser is controlled via a computer and the signal emitted by the piezoelectric is collected after amplification by an acquisition card. In order to make reproducible experiments, we control formation of capillary bridges by keeping constant the humidity rate.
With this experimental system, we can study the dependency of the mean transit time on the height of the packing, on the restitution coefficients, on the size ratio between particles and beads building up the porous medium, on the number of particles flowing in the structure, etc. We can also determine dependency of particle exit position distribution on these parameters, which permit to deduce dispersion coefficients. More information, about this experimental set-up and about the results that have been obtained, can be found in these references: Lominé et Oger, 2006; Lominé, 2007, Lominé et Oger. 2009.
More about flow of particles through porous media:
- F. Lominé & L. Oger, Transit time during the interparticle percolation process, Physical Review E, 82, 4, 041301, 2010
- F. Lominé and L. Oger, Dispersion of particles by spontaneous interparticle percolation through unconsolidated porous media, Physical Review E, 79, 5, 051307, 2009
- Franck Lominé, Ecoulements de particules dans un milieu poreux, PhD thesis, Unniversity of Rennes 1, 2007
- F. Lominé and L. Oger, Transport of small particles through a 3D packing of spheres: experimental and numerical approaches, Journal of Statistical Mechanics: Theory and Experiment, P07019, 2006
- L. Oger & F. Lominé, Particle percolation through a porous medium, Proceeding of Powders & Grains 2005, Edition Balkema, 1, 57-61