Informations générales
Intitulé de l'offre : M/F Doctorant en modélisation de la combustion turbulente des e-combustibles (H/F)
Référence : UPR288-BENFIO-003
Nombre de Postes : 1
Lieu de travail : GIF SUR YVETTE
Date de publication : jeudi 25 septembre 2025
Type de contrat : CDD Doctorant
Durée du contrat : 36 mois
Date de début de la thèse : 1 décembre 2025
Quotité de travail : Complet
Rémunération : 3800 gross monthly
Section(s) CN : 10 - Milieux fluides et réactifs : transports, transferts, procédés de transformation
Description du sujet de thèse
Energetic and environmental context
Climate change and environmental degradation are real threats to the world, with combustion representing the major source of air pollution and a major contributor to carbon emissions. This scenario is prompting the global energy sector to shift from fossil-based systems of energy production to renewable energy-sources. Moreover, the new geopolitical and energy market realities also require a drastic acceleration on the energy transition to break Europe's dependence from unreliable suppliers and volatile fossil fuels – as supported by the REPowerEU plan, published by the EC in May 2022, to make Europe independent from Russian fossil fuels well before 2030.
E-fuels (synthetic fuels, power-to-x or powerfuels), are liquid or gaseous fuels of synthetic origin in which renewable electricity is converted into chemical energy in the form of climate-friendly fuels. The adoption of e-fuels, produced from electricity, are now widely recognized as a critical step to meet the Green Deal and REPowerEU's goals. Another major advantage of e-fuels is that they can be integrated in existing infrastructure.
Scientific issues
Engineers in charge of the design of future industrial combustion chamber fed by e-fuel need high fidelity computation tools to select the appropriate operating conditions and optimize the burner geometry. A major difficulty is related to the complexity of combustion chemistry (Sorrentino et al., 2024). For instance, detailed chemical schemes of ammonia or methanol combustion require hundreds of species and thousands of reactions to obtain an accurate prediction of nitrogen oxide formation. For reasons of computing time, the detailed mechanisms that describe this complex chemistry must be reduced before being used in CFD codes (Fiorina et al., 2015). An interesting method is the virtual chemistry method, whose principle is shown in Fig. 1 (Cailler et al., 2017). The originality of the approach consists in introducing virtual species and reactions whose thermodynamic and chemical properties are optimized by machine learning algorithms to retrieve properties of reference flames gathered in a learning base. A virtual scheme consists of a main block that models the heat release from the flame and sub-mechanisms each dedicated to a particular pollutant. Virtual kinetic sub-mechanisms have so far been developed by EM2C to predict pollutants such as carbon monoxide (Maio et al., 2019), nitrogen oxides (Maio et al., 2020) and soot particles (Maldonado et al., 2021). An efficient virtual scheme remains to be developed for CH4-H2-air chemistry.
The second difficulty is caused by turbulent flow regime encountered in practical applications. Due to the limitation of available computing power, small spatial and temporal scales are not resolved in a CFD simulation of an industrial combustion chamber and must be modelled. Through several studies, it has been showed that virtual chemistry combined with Large Eddy Simulation (LES) approach is efficient to simulate complex flame regimes, encountered in non-adiabatic industrial combustion chambers. These virtual schemes have been introduced into large-scale CFD simulation codes (LES, Large Eddy Simulation). The coupling strategy is based on the Thickened Flame model for LES (TFLES) (Colin et al., 2000), which is well suited to premixed or partially premixed flames, characteristic of the regimes encountered in aeronautical combustors. Examples of simulated carbon monoxide and nitrogen oxide formation in flames representative of gas turbine combustors are shown in Fig. 2.
PhD objectives
The objective is first to develop and validate a virtual chemical scheme for the combustion of two e-fuels: ammonia and methanol. Then the virtual scheme will be coupled with a turbulent combustion model to perform Large Eddy Simulations of e-fuel turbulent flames. The method will be validated by comparing virtual chemistry solutions against experimental data. Turbulent flame simulations will be conducted by the PhD student at Safran Tech with the objective of transferring the method to our industrial partner, who is especially interested by the prediction of nitrogen oxides formation.
Contexte de travail
The doctoral study will take place at the EM2C-CNRS laboratory located at CentraleSupélec, Université Paris-Saclay (Gif-sur-Yvette, France). The recruited student will be enrolled to a 3-year Ph.D. program at the University of Paris Saclay. Two secondment periods are foreseen for each candidate: a 12-month secondment at Polytechnic University of Milano and a 3-month secondment at Safran Tech.
The position is located in a sector covered by the protection of scientific and technical potential (PPST), and therefore, in accordance with regulations, your appointment requires authorization from the competent authority of the MESR.
Le poste se situe dans un secteur relevant de la protection du potentiel scientifique et technique (PPST), et nécessite donc, conformément à la réglementation, que votre arrivée soit autorisée par l'autorité compétente du MESR.
Contraintes et risques
NA