Detailed numerical simulations of porous media combustion using ammonia and hydrogen as fuels: multi-physics coupling and modelling

With increasingly stringent climate change regulations, developing low-emission, carbon-free burners has become crucial for industry and a technical challenge for researchers. Ammonia (NH3) and hydrogen (H2) are the main carbon-free fuels under consideration. H2 burns easily but is hard to store and transport, while NH3 has low flame speeds but is supported by an existing infrastructure. A promising approach is partial ammonia cracking at the burner site, creating NH3/H2 mixtures with improved combustion properties. However, these mixtures emit significant amounts of NOx unless operated at very low fuel/air equivalence ratios (FAER), which are challenging to control in turbulent burners.
An alternative investigated in this PhD is the use of porous burner technology. The recirculation of heat within the porous material can stabilize flames at low FAER, potentially reducing NOx emissions. Developing porous burners requires understanding complex physics such as heat conduction, radiative transfer, flame stabilization, and surface chemistry, which are difficult to capture experimentally due to the small scales and opacity of the matrix. Consequently, computational fluid dynamics (CFD) is the best approach for improving these burners.
This PhD aims to investigate NH3/H2 flames in porous burners using direct numerical simulations (DNS) to understand NOx formation mechanisms. The research, in collaboration with CEA, will utilize the CFD code CONVERGE, employing adaptive mesh refinement for better resolution in key areas like heat transfer and flame chemistry. Reduced NH3/H2 mechanisms will be used for combustion chemistry, conjugate heat transfer (CHT) and radiative heat transfer (RHT) will be included. The study will focus on a reference experimental setup, exploring key parameters such as FAER, inlet mass flow, and porous topology. Surface chemistry's role in NOx emissions will also be explored. This research is expected to be published in peer-reviewed journals.

Keywords: Porous burner, 3D CFD, hydrogen and ammonia combustion modelling, heat transfer, radiative transfer

• Academic supervisor    Dr Olivier COLIN, IFPEN, ORCID: 0000-0002-8947-3490
• Doctoral School    SMEMAG, Université Paris-Saclay
• IFPEN supervisor    Dr Karine TRUFFIN, ORCID: 0000-0003-0888-9003
• PhD location    IFP Energies nouvelles, Rueil-Malmaison, France 
• Duration and start date    3 years, starting in the fourth quarter 2025 (Novembre 3)
• Employer    IFP Energies Nouvelles
• Funding    PEPR SPLEEN AMHYABLE (https://www.pepr-spleen.fr/projet/projet-amhyable/)
• Academic requirements    University Master degree (or equivalent) involving Computer science, Fluid mechanics and/or energetics
• Language requirements    English/French level B2 (CEFR) or willingness to learn French
• Other requirements    Programming skills (Python, C++), numerical analysis

To apply, please send your cover letter and CV to the IFPEN supervisor indicated here below.