Multi-physical CFD simulations of two experimental hydrogen-air flame burners

IFP Energies nouvelles (IFPEN) est un acteur majeur de la recherche et de la formation dans les domaines de l’énergie, du transport et de l’environnement. De la recherche à l’industrie, l’innovation technologique est au cœur de son action, articulée autour de quatre priorités stratégiques : CLIMAT, ENVIRONNEMENT ET ÉCONOMIE CIRCULAIRE, ÉNERGIES RENOUVELABLES, MOBILITÉ DURABLE et HYDROCARBURES RESPONSABLES.

L’engagement d’IFPEN en faveur d’un mix énergétique durable se traduit par des actions visant :

• à gagner en efficacité énergétique ;
• à réduire les émissions de CO2 et de polluants ;
• à améliorer l’empreinte environnementale de l’industrie et des transports ;

tout en répondant à la demande mondiale en mobilité, en énergie et en produits pour la chimie.

Dans cet objectif, IFPEN développe des solutions permettant, d’une part, d’utiliser des sources d’énergie alternatives et, d’autre part, d’améliorer les technologies existantes liées à l’exploitation des énergies fossiles.

Multi-physical CFD simulations of two experimental hydrogen-air flame burners  

The use of hydrogen as a fuel is a particularly interesting way to produce heat directly (process engineering) or indirectly (individual or collective boilers), which still requires many research efforts for large-scale deployment.

The use of hydrogen in a burner, as a substitute for gaseous hydrocarbons for example, is not a simple change of fuel, with an evolution of the calorific value. The combustion characteristics are strongly modified: higher temperature and flame speed, reduction of the ignition energy by an order of magnitude, extension of the flammability range, modification of the emission spectrum (UV range) which can limit its use in certain industrial fields.

At the same time, the very significant reduction in the quenching distance, i.e., the minimum distance between the flame front and the wall, can cause the appearance of potentially harmful phenomena for the burner: premature deterioration accentuated by the high-water vapor content of the burned gases, appearance of hot spots and increased risk of flashback.

The high diffusivity of hydrogen is also an essential point to consider because, beyond the associated safety problems, it implies a strong decrease of the Lewis number, which compares the diffusion of heat to that of mass. For hydrogen, the faster mass diffusion tends to increase the thermo-diffusive instabilities, compared to hydrocarbon flames. Finally, the production of nitrogen oxides must be the subject of particular attention because the control of this pollutant is essential to perpetuate the use of hydrogen burners.

The burners used in many boilers are premixed and have a cylindrical geometry, made of a multi-perforated structure allowing the development and stabilization of the flame. To improve the homogenization and to prevent flashback risks, a metallic fabric can cover the burners in some configurations. CFD is a recognized key-tool that can help the retrofitting process giving access to a high-fidelity 3D representation of the investigated technological configurations. The simulation fidelity can be further improved if heat transfer toward the wall (convective and radiative) as well as solid conduction are accounted in the simulation.

In line with the knowhow on combustion and CHT modelling, IFPEN is building-up several project proposals on the introduction of alternative e-fuels in industrial burners.

This internship proposal aims at pursuing the work initiated in the context of the collaboration with CETHIL, CORIA and CETIAT. In this context, this study proposes a numerical analysis of 1/ a laminar air-hydrogen premixed flame on an academic experimental bench composed of a multi-perforated plate and 2/ a swirled bluff-body turbulent burner.

• The objective of the first study is to determine the influence of the injection plate, in terms of size, shape and periodicity of the injection ports, on the stabilization of premix flames (stabilization domain). A study of the reactive zone and the topology of the flames will be carried out. Particular attention will be paid to the thermal coupling between the flames and the perforated injection plate.
• The aim of the second configuration is to assess the impact of radiative transfer as well as solid conduction in the wall chamber on the flame dynamics and NOx emissions.

Comparisons with measurements will allow to validate the results, in terms of aerodynamic field, flame shape and position, plate temperature and NOx emissions.

The analysis of all these data will improve the understanding of the stabilization of premixed hydrogen-air flames on these types of burners. From a practical point of view, this study will also provide elements to help the design of burners to extend their range of use by integrating the increased risks of flashback related to the use of hydrogen

Requested profile and skills:

• Master M2 and/or Engineer (Equivalent Bac +5)
• Knowledge of theoretical combustion and CFD (theoretical and/or practical). Ideally with a first experience in CFD in an internship or project with a research or commercial code.
• Experience with a coding language (ideally Python or C++)

Tutors IFPEN: Dr. Karine Truffin, Ing. Paul-Georgian Luca, Dr. Cedric Mehl
Tutor CETIAT : Lucio Taddeo
Duration and dates: 6 months starting in the first semester of 2024.

Practical information:

• The intern will be granted by CETIAT with a financial compensation.
• The internship will take place at IFP Energies nouvelles in Rueil-Malmaison (west of Paris).

Interested? Send a motivation letter and your CV !

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