Hereafter come summaries for the short and long projects now finished and selected in the frame of the 2011 Call of LabEx EMC3:
OPTI GP RE
Integrated simulation / optimization methods for the analysis of low or high Reynolds number reactive flows.
Axis 2 : Clean Combustion – CORIA/LOMC
The OPTI GP Re project combined the complementary expertise of the two teams from LOMC and CORIA laboratories to develop multi-physics simulation methods capable of threating an entire process (reactive or not) where occur simultaneously low and large Reynolds flows. The LOMC team contributes by its expertise on flows in fibrous media and the CORIA group with knowledge on large Reynolds reactive flows. Specialized methods in the optimization of these flows are implemented and applied in conjunction with two types of flows.
Leader : Luc Vervisch (CORIA)
Implementation of high-resolution characterization techniques on a material for petawatt laser chains
Axis 1 : Energy Materials – CIMAP/GPM
The fluorite crystals doped with ytterbium ions (CaF2: Yb3+) have become increasingly important in recent years for use in laser power chains. This material distinguishes itself from other laser materials becau on sse of its original spectroscopic properties, which resemble those of a glass, while maintaining the benefits of a crystal system. These unique properties are due to a very particular arrangement of ytterbium in the CaF2 matrix ions. Previous studies based on theoretical models have shown that the ytterbium atoms arrange themselves in the form of nanoscale hexameric clusters.
However, no experimental observation of these clusters has enabled so far to confirm the theoretical models. Given the interest in it as a gain medium, it is essential to increase our knowledge of this system to better understand its spectroscopy and laser properties. Thus, MATISS project focuses on the study of the microstructure of the material at the atomic scale, to determine experimentally the organization of ytterbium ions in CaF2 matrix firstly and secondly to correlate these microstructural properties to luminescence properties of the material. For this, CIMAP and GPM teams has to link three characterization techniques: 3D atom probe tomography (SAT), high resolution transmission electron microscopy (HRTEM ) and spectroscopy. These experiences are accompanied by theoretical studies that deepen the modeling of such system.
Leader : Patrice Camy (CIMAP)
Blue laser sources in femtosecond REGIME and characterization of transparent phase objects
Axis 3 : Multidisplinary Research – CIMAP/CORIA
This is an exploratory research program on the development of embeddable laser measurement systems combining the development of femtosecond fiber laser sources and development of measurement techniques for the characterization transparent phase of objects in extreme conditions. These studies are part of the future development of airborne sensors for the detection of dust and ice crystals in clouds.
The results have established on one hand a technique for measuring small transparent objects in degraded weather conditions (fog, turbulent atmosphere) by holographic reconstruction. The developed metrology led to a patent on the ultrafine wavefront measurement for the detection of small objects by phase discontinuity. On the other hand, the project has enabled the development of a short pulse laser which was the result of an industrial partnership with IXFIBER (Lannion) system. The SOLAIR short project both ambitious and innovative continues today through many long projects driven by industrial partners such as Zodiac Aerospace, Airbus, 3S Photonics or DGA.
Fig. 1: femtoseconde laser source with Nd3+ doped fiber
Leader : Mathieu Laroche (CIMAP)
Atom Probe Tomography combined with ion, photon and electron spectroscopies
Axis 3 : Multidisplinary Research – GPM / CORIA / CIMAP
The ASAP project (2012-2016) aimed at spreading the specter of analysis of the Atom Probe Tomography (APT) to all sorts of materials, especially the dielectric insulators by studing the physical mechanisms at stake in the evaporation when under the pressure of a laser-assisted intense field.
To achieve this goal, the conception of test rigs was necessary to access new information.
Practical solutions have been proposed, especially concerning the samples preparation and the laser-enlighting conditions to improve the analysis results with the APT on insulating materials. It then proved the interest to combine optical, electronic and structural information from a same nanometric sample in order to establish relations between structure and properties.
The works led in the frame of the ASAP project opened new perspectives for the development of this new device assembling an APT with optical, ionic and electronic spectroscopies. This project helped the researchers to create new contacts and draw up new national and european collaborative projects. 18 publications and 35 communications within national and international conferences have been linked to this collaboration.
Fig. 1: Representation of the combination of the Atom Probe Tomography with electronic, ionic and optic spectroscopies
Leader : Angela Vella (GPM)
Mesocombustion and Thermoelectricity
Axis 3 : Multidisplinary Research – CORIA / CRISMAT
The MESOTHERM project (2012-2016) aims at facing nomad needs in micro-sources of power production by setting up of the prototype of an electricity generator combining a centimetric combustion chamber and thermoelectric materials.
Going from the skills in CRISMAT in thermoelectricity and CORIA in combustion, the main objective was to optimise a portable combustion chamber with dedicated numerical tools (about 1 cm3) developed before in CORIA.
The MESOTHERM project enabled to develop and validate modelling and simulation tools (semi-complex chemical kinetics, semi-automatic meshing, dynamic distribution of charges, DTFLES (model of dynamic thickened flame) and EEM (Energy and Emissions Model) approaches; and the use of YALES2 and FLAMEX codes) for the combustion of centimetric scales for swirl-type flows of hydrocarbures and hydrogene mixing.
These tools developed during this project are also useful for the combination of thermal study and fluid mechanics (conjugate heat transfer) and for the analysis and the simulation of thermoelectric materials like Functionally Graded Material (DyCo code, developed within the project, modelisation of dynamical networks combined in 3 dimensions and using a numerical strategy such as discrete networks / finite volumes. This software also enables the treatment of global and local flows constituted by the coupled transport of matter (charges) and energy. Its main innovation holds in its ability to manage strong disparities in thermoelectric coefficients while preserving the flow continuity.
The MESOTHERM enabled the development of a first prototype equipped with an heating tool rather than a combustion chamber. Besides, 7 publications and nearly 20 communications in national and international conferences were produced during this period.
The axis of research developed in MESOTHERM have then been extended through the submission of two ANR projects and the involvement of numerous industrial and academic partners shows the interest of the scientific community and the industry towards the coupling of this innovative design. Industrial: HBOB in Grenoble, ST-Microelectronics in Tours ; Academics: LIED Paris Diderot, IEF Paris Sud Orsay, INRIA Sophia Antipolis, LEGI Grenoble, INRIA Bordeaux, and international: Valence University (Spain), QED Brisbane (Australia), TEI Sterea Ellada (Greece).
Fig. 1: Representation of the MESOTHERM prototype (combination of a combustion chamber with a thermoelectric device)
Leader: Yves d’Angelo (CORIA, maintenant Antipolis (Nice))
Turbulence and Viscoelasticity on Complex Fluids
Axis 2: Clean combustion – LOMC / CORIA
The TUVECO project (2012-2016) aimed at leading complementary studies on turbulence in two hydrodynamic model systems in order to answer to face the issues both encountered by the scientific community and the industry:
- the development of thermal turbulence in closed systems in relation with the thermal transfert efficiency in rotating machines and in propulsion systems
- and the viscoelastic turbulence in open systems in relation to spray stability and the formation of sprayx in liquid complex or the change of thermal properties in fuels and oils by polymeric additives.
The studies of this project combined experiments, modelisation and theory by using multiscale analysis.
The project was composed of two workpackages:
- Thermohydrodynamic turbulence of a flow confined between two coaxial cylinders rotating and exposed to a temperature gradient. This study allowed the funding of a performing instrumentation set of stereoscopic PIV. This tool enables the measurement of the velocity field and to extract a third component by conversation theories. These experiments led from the highlight of the role played by the number of vortices on energy dissipation laws in the flow to the characterisation of structures called “solitons” due to a low turnover of a flow with a great temperature gradient.
- The second workpackage focused on the polymere additives role in the transition to turbulence and the creation of streams and sprays. This study, realised in two different flows, enhanced the role of elasticity in polymere solutions on the transition scenario towards turbulence in the Taylor-Couette system and on the creation of new structures in instabilities of viscoelastic sprays. A multiscale study seems to be a good way to optimise the quality of the atomisation according to the flow turbulence in in the injector in order to resolve the problems in the nuclear, aeronautics and automobile sectors.
The works on TUVECO confirmed the relevance of multiscale description in atomisation processes and to improve this concept to obtain a good expertise level and optimise it during the experiments in LOMC on complex mechanisms or during numerical simulations in CORIA.
TUVECO reinfored the cooperation between the teams at LOMC and CORIA to confort skills and know-how on the studies on complex flow turbulence faced in propulsion and combustion. The LABEX funding provided LOMC with a European level test rig for sturies on thermohydrodynamics. Besides, the project allowed to hire 4 PhD students, 2 of which funded through LabEx EMC3, 3 postdoctorates (2 funded through LabEx EMC3) and 6 Master’s students obtained an internship grant to work on the project, two of which pursued with a thesis in LOMC and CORIA.
39 publications and 34 communications were produced in the frame of TUVECO, showing the scientific quality and the success of this project. TUVECO allowed to open new perspectives with the submission of new ANR and regional research projects on these expertise fields and led to the organisation of two workshops on instabilities in complex fluids.
Leader: Innocent Mutabazi (LOMC)
Organometallic catalysts and ionic liquid for the valorisation of bio-resources
Axis 1: Materials for energy – LCMT / LCS / CRISMAT / GPM
The COLIBRI project (2012-2016) aimed at setting up original, clean, efficient and innovative catalysts materials based fon marine-biosourced polymers and to assess their catalytic properties via the following process :
- Elaboration of new catalysts from marine olysaccharides and ionic liquid
- Set up of efficient characterisation methods of these organometallic catalysts before and after use
- Assessment of these catalysts in operando, in the process of relevant reactions
Ionic liquids (IL) possess significant properties in solvation, conductivity, stabilization… However their use is restricted due to their “liquid” state. That’s why their immobilization on solid supports (elaboration of ionogels) has been studied to make experiment and preserve their original properties. These materials have thus found promising applications in several sectors (batteries, sensors, packaging, catalysis…) The nature of the used support is determinant as it strongly impacts the original properties of the IL ; the used supports are mainly inorganic and based on silica ; polymer supports being lesser used despite their ease of elaboration. The use of natural polymers from alginate and chitosan to elaborate support for ionogels is the main originality of the COLIBRI project as well as the use of Bio-ionogels in reaction processes. The characterisation of materials has been realized via microscopy (CRISMAT/GPM) and via solid state NMR (LCS).
The catalytic bio-ionogels have been elaborated from alginate/IL with Pd or Ru components, which are metals used respectively in catalysis fr the Tsuji-Trost reaction (creation of C-C and C-N chemical bonds) and for the reaction of olefin metathesis (creation of C=C bond). They have been prepared via an innovative process implying the IL immobilisation in the biopolymer matrix through freezing followed by freeze-drying. Bio-ionogels studies and characterizations have highlighted their significant catalytic properties, even at low catalytic load so far as the original properties of IL are preserved even improved.
This project has then been followed by new fundingds (ADEME and INC3M Chemistry Federation) involving new academic partners and supported by industrials (Eiffage and Dassault), confirming the growing interest of the industrial community on the first results obtained in the course of the COLIBRI project.
Leader : Isabelle Dez (LCMT)
Innovative ThermoElectric Materials
Axis 1: Materials for energy – CRISMAT / LCMT / GPM
The ITEM project (2012-2016) aimed to develop new thermoelectric materials based on the effects of nanostructuration to limit thermal conductivity. Two complementary approaches have been tackled:
- Axis 1: Nanocomposite polymer approach of thermoelectric materials (CRISMAT-LCMT)
- Axis 2: 3D crystal-chemical approach at the atomic scale of complex oxides in the Ca-Fe-O-S system, by combining analysis techniques via the Atom Probe Tomography “APT” (GPM) and the transmission electron microscopy “TEM” (CRISMAT).
The axis 1, on the nanostructuration of Bismuth telluride particles allowed to achieve sufficient conductivity levels. Some difficulties have been highlighted as very few examples of insulating thermoplastic materials possess Bismuth telluride particles with thermoelectric properties obtained through extrusion or injection. However, this collaboration enabled the emergence of a new research topic in LCMT thanks to the strong interaction with CRISMAT via a regional funding on the elaboration of thermoelectric and organic materials.
The axis 2, in which CRISMAT and GPM labs were involved, brought promising results on the physical properties of CaFe3O5 et CaFe5O7 components, which had not been studied before. The works allowed to identify the evolution of the thermoelectric power of the 2 cited components, which went from an optimum phase just above the room temperature linked to a reversible structural transition, which had not been highlighted before. The ITEM project helped identify the next goals to achieve, especially on the optimisation of thermoelectric properties via the reduction of the thermal conductivity which, for the moment, does not allow an industrial application in its current state. This work also allowed to enhance the presence of inclusions of Fe2O3 in the CaFe5O7 system ; inclusions that can be decreased by post-synthesis treatments via Spark Plasma Sintering. This process allows a light decrease of the resistivity ideal for thermoelectric properties.
The analyses on the new component CaFeO5 and on the brownmillerite Ca2FeO5 developed during this project allowed to highlight their electronic properties. The important conclusion is that the isolated oxysulfide shows a behaviourof semi-conductivity with a particular non-centro-symetrical structure.
The research led during the ITEM project allowed to compare thermoelectric properties of nanopowders with powders synthetized via mechanosynthesis and enhanced the influence of the nanostructuration on the decrease of the percolation threshold. The main part of the project also consisted in analyzing at the atomic scale iron oxides in intergrowths and to correlate extended defects or detected inclusions with their thermoelectric properties. The results of these works have been presented to around 10 conference, including 7 international.
Leader : Denis Pelloquin (CRISMAT)