Referee : 
Mathieu Coquerelle

Members:
Sakir Amiroudine, Eric Arquis, Mejdi Azaiez, Cédric Le Bot, Jean-Paul Caltagirone, Mathieu Coquerelle, Arnaud Erriguible, Stéphane Glockner, Delphine Lacanette, Antoine Lemoine, Pierre Lubin, Thomas Milcent

This thematic group deals with fluid mechanics approached exclusively by numerical means. The research team includes projects ranging from physical modeling, development of numerical methods to massively parallel simulations. These projects are based on the development of specific numerical methods  and Notus CFD code.

Simulations in environmental phenomena:

• Description of the vortex structures under the breaking waves and study of the interaction between the wave and the wind as well as between the swell and the rain.
• Simulation of the propagation of the mascarets and their interactions with structures.
• Simulation of the micro climate in Paleolithic decorated caves.

Flow in supercritical fluids:

• Modeling and simulation of supercritical flows near the critical point.
• Applications to critical fluid problems under variable gravity vibration.
• Materials synthesis with supercritical fluids

Materials and Energy:

• Simulation of fluid, thermal and chemical interactions in order to control the process parameters (composite materials design)
• Design of virtual materials based on phase change materials

Notus: development of an open-source code for incompressible flows.

• Cartesian mesh
• massively parallel computing
• immersed borders
• interface transport (Level-Set, VOF, MOF).

turbulent 3D jet of acetone in CO2 in supercritical conditions

Referee : 

Jean-Christophe Batsale

Members :
Emmanuelle Abisset-Chavanne, Fouzia Achchaq,  Jean-Christophe Batsale, Jean-Luc Battaglia, Stéphane Chevalier, Marie-Marthe Groz, Andrzej Kusiak, Jérémie Maire, Alain Sommier, D. Balageas, E. Ruffio (associate researchers)

This thematic group gathers the main competences of the TREFLE department related to thermal characterization. The collaborations of the last 10 years in the field of chemistry, optics and microelectronics have led the team to consider transposing the initial methods for multi-physics domains such as the imaging of thermochemical and thermoelectric properties in domains as diverse as energetics, microelectronics and biology. The main fields of application are those involving energy conversion and storage. These studies, with a strong experimental character, are intended to be quantitative, in particular by means of inverse methods, and will lead to the understanding, characterization and multi-scale analysis of these systems.

3 main areas of research are developed:

• Photothermal micro and nanoscopy,
• Multispectral Infrared Tomography for the study of multiphysical problems,
• Development of data analysis and processing methods (inverse methods).

In the field of photothermal micro and nanoscopy, the current work aims at increasing the spatial resolution of the thermal microscopy device by exploring the nanometric domain through a thermal AFM. In Infrared multispectral tomography, the focus is on the development of a thermochemical tomograph for a coupled measurement of temperature and concentration in the volume of materials.

In addition to state-of-the-art instruments, a work of valorization is carried out through the creation of several start-ups (Thermoconcept, NeTHIS) and innovation platform (Fahrenheit).

For more information, please visit the team's web page:

Referee : 
Alain Sempey 

Members :
Denis Bruneau, Philippe Lagière, Laurent Mora, Thomas Recht, Patrick Sébastian, Alain Sempey, Tingting Vogt-Wu

The activities of this thematic group aim to introduce innovation into the design processes of buildings and energy systems in order to achieve performance bond.

In the preliminary design phase, methods are carried out to:

• define and evaluate performance indicators,
• to draw up technical specifications to go from concept to prototype,
• to optimize performance by multi-criteria approaches and risks analysis of non-achieving desired performance

After the development of the prototype, methods are implemented to verify this performance, to detect defects, to optimize control and thus provide information to improve the involved decision aid process.

In building design activities, the developed methods allow to account for uncertainties related to the design parameters; lead to the implementation of experimental validation methods of models, and thus to limit the risks of non-achieving the expected performances.

For energy components and systems, we can mention:

• the development of free cooling energy exchanger and storage systems based on phase change materials,
• the development of efficient energy systems for the agro-food industry,
• the capture of energy in road pavements
• the development of integrated hydraulic networks in buildings.

For each application, it is necessary to formalize decision variables and objective functions in order to optimize system performance.

energy exchanger and storage systems based on phase change materials

Referee : 
Aziz Omari

Members :
Azita Ahmadi, Yannick Anguy, Henti Bertin, Cécile Gaborieau, Wahbi Jomaa, Didier Lasseux, Aziz Omari, Guiseppe Sciume, Jean-Rodolphe Puiggali, Marc Valat 

The research carried out by this thematic group concerns heat, mass and momentum transfer in porous media and associated thermodynamics. These transfers are made complex by the properties of the concerned fluids, by the internal topology of the porous media and their heterogeneity, by the flow regimes and the interactions between the flowing fluids and the porous skeleton.

The research focuses on studying transfers at the pore scale, either on macroscopic or lab scale or at larger scales. The used approaches for this purpose are modeling, numerical simulation and experimental approaches with a constant concern to link the transfer phenomena at small scales to properties and behaviors at larger scales.

Monophasic and polyphasic flows are either simulated by solving the equations of motion at the pore scale, then macroscopic laws are obtained by means of appropriate scaling techniques and closure equations or experimentally giving access to the distribution of the phases and their relative permeabilities. Flows of complex fluid are also being investigated.

In the case of separation and dehydration studies, the coupling between the transfers and the deformability of the porous medium is necessary. Thus, using a multi-scale, multi-physical and multidisciplinary approach, it is possible to model the dehydration of complex products and to qualify the product and process interactions.

Large-scale experimental means such as the environmental microscopy platform are also used for this research and allow to have transverse operations with the other departments.

Simulation of a water-air diphasic flow in a pore network model 

Referee : 
Jean Toutain 

Members :
Fouzia Achchaq, Mejdi Azaiez, Marie Duquesne, Cédric Le Bot, Pierre Monneyron, Jean Toutain

The research of this thematic group deals with the study of heterogeneous phase transitions and transitions in complex environments where interfaces and confinement can play a predominant role on thermodynamic equilibria and on transformation mechanisms and kinetics and dynamics of transfers.

The challenge is to understand and model these effects to guide the design of new materials in the energy field with improved macroscopic properties and behaviors.

Among the themes addressed, we can mention:

• Development and study of nanostructured phase change materials (PCM) and carbon/ PCM composites,
• fusion-crystallization and of solid-gas reactions in porous media,
• mechanisms and kinetics of formation of peritectic structures in the presence of carbon nanostructures or crystallization by shearing of super-cooled liquids or amorphous phases.

The scientific approach adopted involves a strong synergy between theoretical, experimental and numerical approaches, which are often original.

In particular, some new experimental methods are developed. They are based on multi-purpose thermal imaging techniques, including thermal characterization of heterogeneous materials, determination of phase diagrams, quantitative study of the probability of nucleation, measurements of crystallization kinetics, etc.

These experimental developments are complemented by the development of model inversion algorithms using original projection approaches on reduced orthogonal bases.

graphite foam for energy storage and phase change simulation