Nos collaborations

L’ANR Pc2TES : Peritectic compounds for compact thermal energy storage at high temperatures - Contact local : Philippe Legros

L’ANR Fluididense : Concentrated suspensions : towards denser and less viscous materials - Contact local : Grégory Hauss


Pc2TES : ANR-16-CE06-0012-01

• Présentation de Pc2TES :
  Les composés péritectiques pour permettre le développement de technologies de stockage regroupant tous les avantages des technologies existantes ou en cours d’étude, sans toutefois en avoir les inconvénients.

L’objectif général du projet Pc2TES est le développement de ces nouveaux types de matériaux avec un potentiel élevé de stockage d’énergie thermique, compact et rentable, pour des applications à hautes températures. L’idée novatrice consiste à utiliser des composés chimiques formés lors de transitions péritectiques, transitions au cours desquelles l’énergie thermique est stockée selon deux processus consécutifs : un processus de fusion / solidification et une réaction chimique liquide / solide. Cette capacité à combiner différents types d’énergie (sensible, latente et chimique) dans un seul et même matériau fait des composés péritectiques des matériaux alternatifs particulièrement compétitifs.

Pour en savoir plus...

Film : Partie 1 - Version française

Film : Partie 1 - Version anglaise

• Partenaires :

  I2M : Institut de Mécanique et d’Ingénierie - Bordeaux, UMR CNRS 5295
  Contact : Fouzia Achchaq

IJL : Institut Jean Lamour - Epinal, UMR CNRS 7198
Contact : Contact : Alain Celzard

ICMCB : Institut de Chimie de la Matière Condensée de Bordeaux - Bordeaux, UMR CNRS 5026
Contact : Eric Lebraud

PLACAMAT : PLateforme Aquitaine de CAractérisation des MATériaux - Bordeaux, UMS CNRS 3626
Contact : Philippe Legros

FLUIDIDENSE : ANR-17-CE07-0040
-*Présentation de FLUIDIDENSE :
Concentrated suspensions : towards denser and less viscous materials

Carbon blacks are the most widely used nanoparticles in rubber to reinforce tires. Their production contributes much to air pollution and to the greenhouse effect. The introduction of silica particles in tires, to replace partially carbon black particles, is therefore a major ecological advance. While significantly reducing the environmental footprint of tires, these particles have reduced the tires rolling resistance, leading to a reduction in fuel consumption and CO2 emissions of up to 5%. Production of precipitated silica for "green tires", however, remains a major source of water and energy wastage. Indeed, to date, the process requires to handle moderately concentrated suspensions of silica particles, with a viscous fluid behavior that is quite simple, the water of which must ultimately be dried. A substantial ecological progress would therefore result from the possibility of handling more concentrated but still fluid suspensions.

The evolution of solid volume fraction of particles suspended in a Newtonian suspending fluid. Same vertical slice of the 3D volume fraction fields at the following times (a) t=157 s, (b) t=402 s, (c) t=1877 s, (d) t=2127 s, (e) t=2627 s, and (f) t=2877 s. From Gholami et al. 2018

The objective of the FLUIDIDENSE project is to make major advances in the description and the understanding of the behavior of concentrated suspensions, the flows of which tends to jam and to be inhomogeneous, and to provide new paths for the formulation of concentrated suspensions that can be handled. In this wide field of research, it is crucial to focus on a material whose surface physicochemistry is controlled, and to study in depth all the aspects of its behavior, in relation to the interparticle interactions that has to be characterized explicitly. In view of the application, we will focus the study on suspensions of amorphous silica particles, which will be synthesized by varying their shape, their degree of aggregation, and their surface properties. The originality and the strength of the proposed approach are that it relies on a study of the same systems using a set of advanced techniques to locally characterize the flows of silica suspensions (velocity profiles by ultrasonic velocimetry, structure/properties relationship by rheo-SAXS, development of concentration inhomogeneities by X-ray radiography) and their morphological properties (SAXS, MEB), as well as their microscopic properties (original measurements of normal and tangential interparticle forces in the suspending fluid). For all the studied particles, a multi-scale characterization of the behavior will be available, the synthetic vision of which will provide a clarification of the conditions under which dense, fluid and homogeneous suspensions can be formulated.
Within this project, PLACAMAT is in charge of the suspension flow characterization by using X-ray radiography. A rheometer from the LOF laboratory has been adapted to run in-situ testing in our GE v|tome|x s tomograph, mainly in parallel plates and couette configurations. X-ray radiographs are recorded during different loading configurations and then analyze to measure in 3D the development of the concentration inhomogeneities. The advantages of using radiographs are first to analyse kinetics of the phenomenon and then, thanks to the axial symmetry configuration of the flow, to obtain the 3D solid volume fraction fields.