Modélisation des écoulements multiphasiques réactifs
Modélisation et simulation de la propagation des feux de forêts
Thermodynamique des mélanges
Thermodynamics, Numerical Waves, Interfaces, Combustion Team
Présentation
The TONIC team is developing an activity of modeling of strongly multi-scale phenomena. It covers in particular multiphase and/or reactive flows, from the scale of the isolated injector (a few mm) to the scale of a fully developed forest fire (several hectares).
Adapted numerical methods are developed in parallel, in particular for soil imaging (detection of slicks by acoustic analysis), or for the modeling of radiative transfers.
In parallel to these multi-scale developments, analytical work is carried out to support the construction of models. An important research effort is devoted to the modeling of the thermodynamics of multiphase mixtures (thermochemical equilibrium calculations, complex thermodynamic closures), or to the development of reduced kinetic models for combustion.
Jinhua Lu, Thomas Gregorczyk, Song Zhao, Pierre Boivin. Phase-field-based recursive regularized multiphase lattice Boltzmann model with a consistent pressure scheme. International Journal of Multiphase Flow, 2026, 195, pp.105500. ⟨10.1016/j.ijmultiphaseflow.2025.105500⟩. ⟨hal-05344425⟩ Plus de détails...
Multiphase lattice Boltzmann models with enhanced stability and no deviation terms.
• Consistent pressure scheme decoupled from density and viscosity variations.
• The proposed model shows superior numerical stablity and accuracy.
Jinhua Lu, Thomas Gregorczyk, Song Zhao, Pierre Boivin. Phase-field-based recursive regularized multiphase lattice Boltzmann model with a consistent pressure scheme. International Journal of Multiphase Flow, 2026, 195, pp.105500. ⟨10.1016/j.ijmultiphaseflow.2025.105500⟩. ⟨hal-05344425⟩
Benoît Péden, Pierre Boivin, Nicolas Odier. Large-Eddy Simulation of a 3D airblast injector using a diffuse interface four-equation model: effects of evaporation and combustion. Combustion and Flame, 2026, 285, pp.114771. ⟨10.1016/j.combustflame.2026.114771⟩. ⟨hal-05557933⟩ Plus de détails...
This work presents Large-Eddy Simulations of a three-dimensional airblast-type injector using a diffuse-interface Multi-Fluid approach. A four-equation model is employed, including a consistent phase transition solver and a thermodynamic closure suitable for evaporating and reacting flows. The influence of evaporation and combustion on the spray and flow dynamics is investigated through a comparative analysis of cold, evaporative, and reactive configurations. The method is first validated against reference results and known behavior for similar injector geometries. It is shown that the addition of evaporation significantly alters the liquid fuel distribution, particularly in the inner recirculation zone, while combustion further modifies both liquid and gaseous fuel fields due to temperatureinduced evaporation and fuel consumption. The reacting case exhibits typical flame features, including hollow cone structures and localized high-temperature zones near stoichiometric mixture fractions. These phenomena align well with expected flame behavior under airblast conditions. Phase transition and combustion also have a notable impact on the velocity field, with increased expansion and stronger recirculation induced by heat release. The proposed model captures these effects in a unified framework. Finally, the present multi-physics approach enables consistent and efficient simulation of multiphase, reactive sprays, providing physical insight into the coupled interaction between atomization, evaporation, and combustion. The method shows good numerical performance on the 3D injector, with a reduced computational time of 2.1 × 10 -5 s.mpi/node/it, which has no overcost compared to the Lagrangian reference model. The fully explicit treatment of the equation of state (NASG) ensures excellent robustness on complex geometries, while avoiding the iterative procedure required by cubic-type EoS. These numerical properties make the DIM suitable for industrial LES configurations involving evaporation and combustion, and further model development.
Benoît Péden, Pierre Boivin, Nicolas Odier. Large-Eddy Simulation of a 3D airblast injector using a diffuse interface four-equation model: effects of evaporation and combustion. Combustion and Flame, 2026, 285, pp.114771. ⟨10.1016/j.combustflame.2026.114771⟩. ⟨hal-05557933⟩
Marc Le Boursicaud, Jean-Louis Consalvi, Pierre Boivin. Prediction of hydrogen–ammonia blends autoignition. Combustion and Flame, 2026, 285, pp.114713. ⟨10.1016/j.combustflame.2025.114713⟩. ⟨hal-05469163⟩ Plus de détails...
The growing interest in hydrogen as an alternative energy vector has raised new technological challenges, in particular regarding its storage. This has motivated increasing attention to ammonia as a hydrogen carrier. In parallel, the use of hydrogen-ammonia blends as combustible fuels has attracted significant interest, as such mixtures can be easier to handle in some applications than pure hydrogen, while still enabling carbon-free combustion.In this context, the present study focuses on modeling the ignition of arbitrary gaseous hydrogen-ammonia-air blends. First, the minimal chemical description required to accurately capture the ignition delay of these mixtures is identified, revealing three main ignition regimes. Ignition delay formulas are then derived for these regimes by extending methods previously developed for pure hydrogen and syngas. The resulting ignition time expressions are subsequently combined into a unified formulation, valid across a wide range of pressures, temperatures, and fuel compositions. Finally, modifications to a recently published passive scalar model for CFD tools are introduced so as to accurately predict ignition events in hydrogen-ammonia-air mixtures while reducing computational cost. Novelty and
Marc Le Boursicaud, Jean-Louis Consalvi, Pierre Boivin. Prediction of hydrogen–ammonia blends autoignition. Combustion and Flame, 2026, 285, pp.114713. ⟨10.1016/j.combustflame.2025.114713⟩. ⟨hal-05469163⟩
A. Fayet, Stéphane Mimouni, Luc Favre, Catherine Colin, Pierre Boivin, et al.. Modeling and numerical simulation of boiling flows: application and dataset release of the DEBORA experiment. International Journal of Heat and Mass Transfer, In press. ⟨hal-05571906⟩ Plus de détails...
Computational Fluid Dynamics (CFD) is widely used in nuclear engineering for safety related studies or for new design investigations. Co-developed by EDF, CEA, ASNR and Framatome, the NEPTUNE_CFD code is specialized in nuclear thermal-hydraulic applications allowing the simulation of two-phase flows on complex geometries. Recently, a new Heat Flux Partitioning (HFP) model has been proposed by Favre et al. [1] for a thorough description of the boiling phenomena, including, among others, the effect of wall sliding bubbles. However, an excessive increase in computation time follows the subsequent modeling improvement. This paper presents an optimization of the bubble sliding calculation returning to a reasonable computation time compatible with industrial applications. The newly developed model is then validated using NEPTUNE_CFD and compared to the DEBORA experimental data, featuring R12 coolant boiling flow within a characteristic non-dimensional scope of a Pressurized Water Reactor (PWR). The improvement in the wall temperature calculation is demonstrated by several simulations implementing the new HFP model. To support the community's validation and benchmarking efforts, the complete DEBORA experimental dataset is made publicly available for the first time as part of this work, provided under a CC BY 4.0 license. This contribution advances both modeling capabilities and data availability, promoting transparency and reproducibility in multiphase CFD for nuclear applications
A. Fayet, Stéphane Mimouni, Luc Favre, Catherine Colin, Pierre Boivin, et al.. Modeling and numerical simulation of boiling flows: application and dataset release of the DEBORA experiment. International Journal of Heat and Mass Transfer, In press. ⟨hal-05571906⟩
Journal: International Journal of Heat and Mass Transfer
Ziyin Chen, Song Zhao, Bruno Denet, Christophe Almarcha, Pierre Boivin. A three-dimensional study on premixed flame propagation in narrow channels considering hydrodynamic and thermodiffusive instabilities. Combustion and Flame, 2025, 281, pp.114392. ⟨10.1016/j.combustflame.2025.114392⟩. ⟨hal-05344216⟩ Plus de détails...
In numerical studies of quasi-2D problems, such as laminar flame propagation through a slit, the quasi-2D assumption is commonly applied to simplify the problem. However, the impact of the third dimension (in the thickness between walls) can be significant due to strong curvature. The intrinsic Darrieus-Landau instability, the Saffman-Taylor instability, and the thermodiffusive instability lead to curved flame fronts in both the transverse and normal directions and radically change the global flame speed. This study investigates the interaction of these instabilities and their impact on premixed flames freely propagating in narrow channels. Two lean fuel-air mixtures are considered: one with unity Lewis number Le = 1 and another with Le = 0.5. A single-step Arrhenius-type reaction is used for combustion modeling. Joulin Sivashinsky's model [1], termed the 2D+ model, is implemented to capture the confinement effect due to walls. By comparing 3D Direct Numerical Simulations (DNS) and 2D simulations at unity Le, we find that the 2D+ model accurately reproduces confinement effects for channel width h up to 3.6δ T (δ T : thermal flame thickness), extending the validity of Darcy's law.
However, for larger h, interactions between flame curvatures in two directions result in higher flame surface increment and consumption speed. Besides, for 3D cases with Le = 0.5, positive curvature regions on the flame front primarily contribute to the global reaction due to the Lewis effect. Statistical studies on flame dynamics between walls in 3D cases are also
Ziyin Chen, Song Zhao, Bruno Denet, Christophe Almarcha, Pierre Boivin. A three-dimensional study on premixed flame propagation in narrow channels considering hydrodynamic and thermodiffusive instabilities. Combustion and Flame, 2025, 281, pp.114392. ⟨10.1016/j.combustflame.2025.114392⟩. ⟨hal-05344216⟩
6 février 2026
- Study of turbulent transport of energetic particles in nuclear fusion plasmas nuclear fusion plasmas by trajectory simulations and artificial intelligence techniques / PhD Defense Benoît Clavier
Doctorant : Benoît CLAVIER
Date et lieu : le vendredi 6 février à 14h00, M2P2 - salle Labus, Centrale Méditerranée
Abstract: This thesis studies the turbulent transport of charged particles in magnetized fusion plasmas by combining reduced turbulence models, numerical trajectory simulations, and data-driven approaches based on artificial intelligence. After presenting the physical framework of radial transport in a tokamak and the Hasegawa–Wakatani model, Eulerian and Lagrangian diagnostics are developed to obtain reference transport measurements. The work then analyzes the transport of test particles in different turbulent regimes, highlighting the limitations of certain classical approximations and the complexity of energetic particle dynamics. The study is extended to a more realistic three-dimensional ion-temperature-gradient (ITG) turbulence, allowing scaling laws for radial diffusion to be established. Finally, a synthetic turbulence generation model based on a Convolutional Variational Autoencoder (CVAE) coupled with a dynamic model is proposed to efficiently reproduce turbulence and accelerate transport studies, illustrating the potential of data-driven approaches for future research in plasma physics.
Jury
David ZARZOSO-FERNANDEZ - Chargé de recherche - CNRS M2P2 - Directeur de thèse
Emmanuel FRéNOD - Professeur des universités - Université Bretagne Sud - Co-directeur de thèse
Victor TRIBALDOS - Professeur des universités - Universidad Carlos III de Madrid - Rapporteur
Julien LE SOMMER - Directeur de recherche - CNRS, IGE Grenoble - Examinateur
Maxime LESUR - Professeur des universités - Université de Lorraine - Institut Jean Lamour - Rapporteur
Mitra FOULADIRAD - Professeure des universités - Centrale Méditerranée - Président
22 janvier 2026
- Study of Combustion Instabilities Using Lattice-Boltzmann Methods / PhD Defense Ziyin Chen
Doctorante : Ziyin CHEN
Date et lieu : le jeudi 22 janvier 2026 à 13h45; amphi No.1 de Centrale Méditerranée
Abstract: Driven by climate change and the energy transition, hydrogen has emerged as a promising alternative to fossil fuels due to its efficient, carbon-free combustion. However, hydrogen–air flames exhibit strong instabilities, which are amplified in confined environments where wall effects and heat losses play a key role. Understanding these phenomena is essential for the safe design of micro-scale combustion devices.
This thesis investigates the stability of premixed hydrogen–air flames in a Hele-Shaw burner using the Lattice-Boltzmann method. Hydrodynamic and thermodiffusive instabilities are analyzed in both two- and three-dimensional configurations, with and without heat losses at the walls. The simulations reveal the conditions for symmetry breaking and quantify the influence of the Lewis number, channel width, and wall heat losses on flame morphology and propagation speed. Reduced-order models are developed to predict flame front geometry, cusp formation, and flame speed evolution.
These results improve the understanding of confined hydrogen flames and provide predictive tools for the design of safe and efficient micro-combustion systems.
