Informations générales
Intitulé de l'offre : PhD [M/F] AMMONIA FLAME STABILIZATION AND POLLUTANT REDUCTION VIA NANOSECOND REPETITIVELY PULSED DISCHARGES (H/F)
Référence : UPR288-SANDES-002
Nombre de Postes : 1
Lieu de travail : GIF SUR YVETTE
Date de publication : vendredi 7 mars 2025
Type de contrat : CDD Doctorant
Durée du contrat : 36 mois
Date de début de la thèse : 1 juin 2025
Quotité de travail : Complet
Rémunération : 2200 gross monthly
Section(s) CN : 10 - Milieux fluides et réactifs : transports, transferts, procédés de transformation
Description du sujet de thèse
AMMONIA FLAME STABILIZATION AND POLLUTANT REDUCTION VIA NANOSECOND
REPETITIVELY PULSED DISCHARGES
Contexte de travail
This thesis focuses on the experimental study of ammonia (NH3) flames assisted by plasma. NH3 flames are considered as alternatives to conventional carbon-based combustion in industries requiring high temperatures that electricity cannot provide – such as glass, steel, cement production, etc. NH3 flames do not produce CO2, 2 NH3 + 3/2 O2 => 3 H2O + N2. Still, certain combustion regimes can lead to the formation of pollutants harmful to the environment and health: NH3 (health), NO (health and indirect greenhouse effect), and N2O (greenhouse effect). This project aims to reduce the formation of these pollutants by employing Repetitive Pulsed Nanosecond (NRP) electrical discharges. NRP discharges last approximately 10 ns and are generated by voltage pulses of 10-30 kV at a repetition rate of 10 to 100 kHz. This highly energy-efficient technique has been successfully used to stabilize flames of numerous carbon fuels up to powers of 100 kW.
The first part of the thesis will study the fundamental interaction phenomena between NRP discharges and a premixed CH4-air flame already characterized in the laboratory. This study will notably serve to prepare optical diagnostics for the second phase. These optical diagnostics will measure fundamental parameters at the scale of the discharges (temperature, electrons, atomic species, electronically excited species) as well as the thermodynamic state at the scale of the flame (temperature, species). During the second phase, we will study the impact of NRP discharges on an NH3-air mixture in a 10 kW laboratory burner, with flame attachment stabilization. Control of
the discharge regime will be crucial to form a plasma moderately hotter than the flame (2000 to 3000 K) or a plasma at thermodynamic equilibrium (20,000 to 40,000 K). A detailed understanding of the flame-plasma interaction will allow identifying which regime is the most interesting for an industrial application and the main mechanisms of stabilization and pollutant reduction by discharges to enable a future implementation of the technology.
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
no