Mixing and transformations in multiphasic granular materials

Raw materials are often made of granular materials and powders. In many industrial processes, transformations of those grains are required to create the final product, such as blending grains with liquids, mixing different grains or sintering with or without chemical reactions. We study these situations from a physical point of view, by the means of experimental model systems, taking advantage well controlled geometries.

Blending liquid with grains

Pierre Jop in collaboration with Alban Sauret from University of California Santa Barbara

In order to identify the multiple mixing mechanisms, we carry out experiments with different initial liquid distributions. For example dry grains impacting a wet granular media can lead to growing structures that reveal the role of the inertia (fig. left). When a dry granular jet plunges into a water tank, how the liquid invade the graular media? (fig. right)

Mixing dry grains

Kwami Mayeden, Pierre Jop in collaboration with Evelyne Kolb from PMMH, and Stéphanie Deboeuf from Institut Jean le Rond d’Alembert

One of the main concerns when mixing grains is the issue of segregation when the particles properties are different (such as the size), leading to potential structural mal-performance in industrial products such as glass, abrasives, or pills. We study both the effect of the segregation around an intruder, and we also focus on the description of the mixing process considering the granular system as a continuum media.

See also in «Soft matter, liquid films, mixing granular materials»

Drying of thin films of complex liquids Liquid crystals