Post-Doctorat et Contrat de recherche

Ankit SAHAY

Supervisors: Pascale Desgroux, Nathalie Lamoureux,
Duration: Mars 2025-
Funding: 100% PEPR MONTHY. The gross salary is approximately 2800-3100 €/month (depending on
experiences)

In 2021, the French government launched a broad investment plan “France 2030”, in connection with the
ecological transition. This plan aims to decarbonize French industry in order to reduce greenhouse gas emissions
by 35% by 2030. Hydrogen combustion is a promising energy source to reach the carbon neutrality in many
applications, including transport, industrial processes and energy conversion. In particular, the French
acceleration strategy on decarbonized hydrogen is supported by the Priority Research Program and Equipment
(Programme et Equipements Prioritaires de Recherche) PEPR-H2 of the plan “France 2030”.
The MONTHY project is funded by PEPR-H2 for a period of 4 years from 01/10/2022. This project brings together
three French laboratories internationally recognized for their research in combustion and laser diagnostics
(CORIA, EM2C, PC2A) and allows the recruitment of several PhD and postdocs on fundamental research on H2
combustion.
The objectives of MONTHY project are to understand through a joined experimental and numerical analysis the
nitrogen oxides formation in an environment representative of future hydrogen-air industrial combustion
chambers. Results will lead to the first understanding and modeling of the impacts of H2O dilution on NOx
production during turbulent hydrogen combustion
PC2A laboratory is offering a 18-21-month postdoc position, mainly experimental, on the development of laser
spectroscopic diagnostics to obtain quantitative measurements of several key species for understanding of NO
formation in laminar and turbulent H2 flames, building on the expertise of PC2A in the field [1].
One aspect of the project aims to complete the database obtained in the first part of the project in several low
pressure laminar H2 flames selected over a judicious range of pressures and equivalence ratio to cover the various
chemical pathways of NO formation in H2 flames. The measured quantitative profiles of OH, NO were compared
with modelling and have been disseminated with the community through several communications and
publication [2-3]. In order to refine NO formation kinetics, quantitative measurements of H and O atom profiles
are highly desirable. One of the postdoc's tasks will therefore be to implement for the first time the calibrated
two-photon Laser induced fluorescence (TPLIF) technique in H2 flames, drawing on the expertise of PC2A [4-5].
Other species, including minor, are also being considered by LIF, Cavity Ring-Down Spectroscopy (CRDS), FTIR [6].
The second aspect focuses on the implementation of an experimental and numerical strategy dedicated to the
determination of OH and NO collision cross sections in H2 flames. These data need to be re-evaluated in a
collisional context typical of H2 flames, especially under H2O dilution, and are crucial for quantifying 2D-LIF
imaging of species in turbulent flames, such as those studied in the project at the CORIA and EM2C laboratories.
To this end, in addition to the strategy developed at PC2A to determine cross sections, a close collaboration with
the CORIA laboratory will be set up to measure the concentrations of the main species in laminar H2 flames by
Spontaneous Raman Spectroscopy [7], as required to determine the quenching. A wide range of flames offering
different collision environments will be explored, enabling us to test the robustness of the quenching
determination and model before transferring it to turbulent flames.
The project is anticipated to contribute to both realization of industrial-scale hydrogen combustion and the
advancement of fundamental scientific knowledge regarding spectroscopic principles.

Keywords: Laser-based spectroscopic diagnostics, Combustion, NOx emissions
Academic requirements: PhD in the field of chemical or mechanical engineering/spectroscopy/laser
techniques/combustion and a strong aspiration to perform experimental work are required. Experience in
tunable laser metrology is appreciated. Knowledge of LIF, laser absorption. Data post processing techniques will
be considered an asset.

References
[1] Modeling of NO formation in low pressure premixed flames, Combustion and Flame, 163, 557-575 (2016),
Lamoureux et al.
[2] Experimental investigations of NO radicals in premixed hydrogen flames across a wide range of equivalence
ratios, T. Mitra, Y. Fenard, N. Lamoureux, P. Desgroux, 3rd Low Carbon Combustion Meeting, Nancy, France,
April 2024
[3] Understanding NO formation pathways in low pressure burner stabilized premixed lean-to-rich hydrogen
flames, to be submitted to Combustion and Flame, T. Mitra, N. Lamoureux, P. Desgroux,
[4] Direct quantification of O-atom in low-pressure methane flames by using two-photon LIF, PROCI 38 (2021),
pp. 1753-1760, N. Lamoureux, P. Desgroux,
[5] Quantitative measurement of atomic hydrogen in low-pressure methane flames using two-photon LIF
calibrated by krypton. Combustion and Flame, 224 (2021), pp. 248-259, N. Lamoureux, P. Desgroux
[6] Quantitative NH measurements by using laser-based diagnostics in low-pressure flames, PROCI 36, 1313-
1320 (2019), Lamoureux N., Gasnot L., Desgroux P.
[7] Insights into the flow and scalar structures when shifting from methane to hydrogen turbulent flames using
simultaneous PIV – OH PLIF and spontaneous Raman scattering, PROCI 40 (2024) 105708, Rajamanickam K. et al.

Anupam Ghosh

Supervisors: Nathalie Lamoureux, Pascale Desgroux

Support financier: ANR SIAC

Duration: 13 months

To reach the Carbon neutrality target in 2050 as announced Europe in its Green Deal, the electricity demand will be strongly increased for energy, transport and heating/cooling systems. For that, most countries consider clean and renewable energy resources (as wind and solar) as the main energy resources for the future. However, due to their intermittency and the need to keep a secure electricity supply, the energy storage will be an integral part of the modern electricity smart grid. One solution to store the renewable energy excess is what is commonly named ‘electro-fuels’. Hydrogen is often considered as the best candidate but suffers up to now from some drawbacks such as its storage capacity and safety. Another alternative is Ammonia (NH3), which can be considered as a ‘mere’ hydrogen (H2) carrier. So far, most applications rely on preliminary partial thermal cracking of NH3 to N2 and H2 to counteract the high ignition temperature of NH3 and its low flammability (a positive safety characteristic). The lack of knowledge regarding the oxidation chemistry of NH3 and the combustion process itself currently limits the optimization of NH3 combustion.

The SIAC project is 4-years funded by the French Government (ANR) bringing two laboratories (PC2A at Lille, and FITe at Orléans) and CERFACS recognized for their researches in combustion fields from fundamental kinetic to modelling turbulent combustion through experimental investigation of turbulence-premixed flame interaction.

PC2A is offering a 18-24 months postdoc position (starting beginning of 2024), mainly experimental, on topics related to NOx formation in ammonia premixed flames. To reach a better knowledge of the pollutant emission, it is necessary to perform laboratory scale experiments. The proposal is focused on three main targets that address the SIAC project.

First, low-pressure laminar flames will be studied by implementing an original experimental strategy based on advanced laser diagnostics to quantitatively detect radicals in ammonia, ammonia/hydrogen and also in ammonia/NO premixed flames. The experimental work will consist in acquiring a unique experimental quantitative database of NO formation in laminar flames using in‐situ advanced laser diagnostics (laser‐ induced fluorescence (LIF) and absorption) and probe sampling techniques (FTIR), detecting challenging trace species like NH₂ and HNO to clarify the NO routes of formation. This experimental work will be performed in strong interaction with a PhD student already enrolled in the project with the French Environment and Energy Management Agency (ADEME) and the LabEx CaPPA.

Second, chemiluminescence analysis in low-pressure flames will be performed in order to identify the possible correlation between the excited species (NO*, OH*, NH*, NH2*) and the corresponding species in their ground state. This information is fully relevant for the turbulent flame analysis as performed at FITe-Orléans.

Third, LIF and Planar LIF will be implemented in a canonical burner dedicated to the characterization of flame/vortex interaction. This FLAVOR burner from FITe will be installed at PC2A in order to characterize the reaction zone of the wrinkled flame using measuring NH and NH₂.

Keywords: ammonia, NOx emissions, laminar combustion, spectroscopy, LIF, chemiluminescence

Funding: 100% ANR SIAC (Scientific Improvement of Ammonia Combustion) from the French national Agency of Research. The gross salary is approximately 2800€/month (depending on experiences)

Contact e-mail: nathalie.lamoureux()univ-lille.fr, pascale.desgroux()univ-lille.fr

Harsh CHALIYAWALA

Supervisors: Alessandro Faccinetto, Eric Therssen, Xavier Mercier

Duration and starting date: 18 months

Funding: ANR

L’objet du projet ANR INTERSTELLAR (StudyINg ThE photophysics of laRge aSTrophysical hydrocarbon molEcuLar systems using LAboRatory analogues) est d’explorer les similitudes entre les espèces formées dans les milieux interstellaires (ISM) et les flammes génératrices d’espèces carbonées comme les hydrocarbures aromatiques polycycliques (HAPs), les fullerènes et les nanoparticules carbonées, qui seraient susceptibles de jouer un rôle clé dans des phénomènes comme les bandes infrarouges aromatiques (AIBs) et d'autres signatures spectrales spécifiques de l'ISM.

Ce projet vise plus particulièrement à caractériser ces molécules de grande taille similaires à celles de l'ISM et leurs propriétés photophysiques, en utilisant des flammes de laboratoire originales comme sources d'analogues de ces grandes molécules interstellaires et de relier cela aux observations astrophysiques. Pour ce faire, il est prévu de combiner un ensemble de dispositifs expérimentaux de pointe reposant sur des diagnostics lasers in situ et des mesures en ligne dont les résultats seront exploités via des études théoriques.

Ces travaux seront menés en collaboration avec l’Institut des Sciences Moléculaires d'Orsay (ISMO) et le laboratoire Physique des Lasers, Atomes et Molécules (PhLAM) de l’Université de Lille dans un cadre scientifique clairement interdisciplinaire mettant en commun des compétences techniques et équipements de recherche de haut niveau issus des trois laboratoires impliqués dans ce projet, et reconnus internationalement chacun dans leur domaine d’expertise.

Il s’agira essentiellement de caractériser dans des flammes basses stabilisées à basse pression, des espèces potentiellement similaires à celles de l’ISM, au moyen de techniques laser de pointe telles que la fluorescence induite par laser (LIF) et l’incandescence induite par laser (LII) et de méthodes en ligne telles que la spectrométrie de masse (TOFSIMS) ou des dispositifs de type Scanning Mobilty Particle Sizer (SMPS). Des travaux théoriques menés en collaboration avec le laboratoire ISMO viendront compléter ce projet pour aider à l’interprétation des caractéristiques d'émission de la diversité des espèces formées.

Perla TRAD

Supervisors: Guillaume VANHOVE, Laure PILLIER

Duration and starting date: 13 months

Funding: CPER ECRIN (https://ecrin.cper-hautsdefrance.fr/)

Combustion-driven processes are still responsible for a large proportion of energy production and conversion worldwide. Thus major reductions in pollutant emissions and improvements in fuel efficiency should be sought, and can be reached by means of fuel-lean mixtures of renewable fuels. Controlled initiation of the combustion is however a crucial step towards widespread application of such conditions, with wide ranges of application including piston engines, constant volume combustors, gas turbines and aeronautic engines. However, fuel ignition is highly dependent on the chemical kinetics associated with Low Temperature Combustion (LTC) [1].

The chemical mechanisms relevant to LTC include the formation of unstable peroxides, the structure of which reflects the initial fuel. The reactivity of a fuel in this temperature regime is therefore highly constrained by its structure. This is a strong incentive towards the development of predictive models which must be validated with reliable data in this temperature regime and under rarely investigated fuel-lean conditions.

To this end, a burner dedicated to the study of stabilized cool flames has recently been designed and validated in PC2A [2-4]. The potential to perform detailed kinetic studies through a number of optical and analytical diagnostics, including Planar Laser Induced Fluorescence (PLIF), chemiluminescence, thermometry and gas chromatographic techniques, has been demonstrated. Moreover, the potential of Particle Imaging Velocimetry (PIV) techniques for the determination of cool flame propagation velocities has been established. This paves the way towards exciting upcoming experimental campaigns, which are planned in 2024 and to which the candidate will participate:

1- Among them, the panel of diagnostics associated to the burner will be extended to VUV photoionization mass spectrometry/PhotoElectron PhotoIonization Mass Spectrometry, in collaboration with the DESIRS beamline of Synchrotron SOLEIL, allowing the selective detection and quantification of elusive products, such as the hydroperoxides responsible for radical-chain branching.

2- Further development of the PIV technique towards determination of cool flame burning velocities for new fuels will be achieved in collaboration with CORIA and LMFL laboratories.

References

[1] S. S. Goldsborough, S. Hochgreb, G. Vanhove, M. S. Wooldridge, H. J. Curran, C. J. Sung, Advances in rapid compression machine studies of low- and intermediate-temperature autoignition phenomena. Prog. Energy Combust. Sci. 2017, 63, 1-78.

[2] T. Panaget, K. Potier, S. Batut, A. Lahccen, Y. Fenard, L. Pillier, G. Vanhove, How ozone affects the product distribution inside cool flames of diethyl ether, Proceedings of the Combustion Institute 39 (2023) 325-333.

[3] K. De Ras, T. Panaget, Y. Fenard, J. Aerssens, L. Pillier, J. W. Thybaut, G. Vanhove, K. M. Van Geem, An experimental and kinetic modelling study on the low-temperature oxidation of oxymethylene ether-2 (OME-2) by means of stabilized cool flames, Combustion and Flame 253 (2023) 112792.

[4] T. Panaget, N. Mokrani, S. Batut, A. Lahccen, Y. Fenard, L. Pillier and G. Vanhove, Insight into Ozone-Assisted Low-Temperature Combustion of Dimethyl Ether by Means of Stabilized Cool Flames, J. Phys. Chem. A 125 (2021) 9167−9179.

Keywords: Low Temperature Combustion, Kinetics, Pollutant reduction, bio- and e-fuels, optical and analytical diagnostics.

Academic Requirements: A PhD degree in the fields of Combustion Chemistry and/or Laser diagnostic techniques and a strong aspiration to perform experimental work are required.