Franck Lominé

TOPIC 1 : Flows of particles through a porous medium

Presentation

I carried out my PhD thesis in the group “granular materials and foams” of the Institute of physics of Rennes. I studied of transport of particles in a porous structure. The objective of my PhD thesis was to study the flow of grains in a porous environment due to the gravity field.

The handling of granular matter is often a source of many problems. One of them is size segregation, which implies a no homogeneous distribution of the various species of grains, this makes very difficult the realization of homogeneous mixtures. In this work, I am interested in the spontaneous percolation in a granular medium. The phenomenon of spontaneous percolation is defined as the movement of fine particles through an arrangement of larger spheres, due to gravity. Energy is dissipated during collisions, which involve a longitudinal and transverse dispersion of particles. The interest, in the understanding of the phenomena, which govern this kind of transport, finds its justification in problems encountered by industries that use granular materials (pharmaceutical industry, civil engineering...). Being able to mitigate or control the phenomena of segregation, which appear when we try to mix two, or several kinds of grains, is essential in the previously quoted industries.

Thus, a diffusive process, as the one that I am interested in, proves to be a simple and effective way to obtain homogeneous mixtures. Nevertheless, it is necessary to know as well as possible the influence of the various parameters. My research is articulated around two complementary axes: an experimental part and a numerical part. You can obtain further information by consulting the pages that refer to them.