Periodic Reporting for period 4 - LAPLAS (ADVANCED LASER DIAGNOSTICS FOR DISCHARGE PLASMA)
Période du rapport: 2024-09-01 au 2025-02-28
This project develops advanced laser-based plasma diagnostics to study how plasma can stimulate chemical processes for stable, efficient combustion with lower emissions and enable hydrogen production from methane/carbon dioxide mixtures. These complex plasma-induced processes require high temporal and spatial resolution to capture intermediate reactions and species.
Initially, few diagnostic methods existed for controlled plasma studies, especially at atmospheric pressures. Plasma chemistry and combustion span timescales from picoseconds to milliseconds and are highly stochastic. Pulsed lasers are ideal for in-situ studies of reactive species and high-energy electrons. We developed next-generation pico- and femtosecond laser diagnostics to capture species distributions and rapid electron-driven energy transfer—key to plasma-assisted chemistry.
Our goal is to support carbon-free, net-zero fuels like ammonia. Plasma stimulation enhances combustion of varied feedstocks. Plasma conversion of CH₄/CO2 shows promise for producing H2, CO, and valuable hydrocarbons.
Conclusion of the action:
The project successfully produced numerous publications in leading journals. We developed novel optical methods to capture plasma parameters and radicals using single-shot imaging in harsh environments. These techniques enabled investigation of plasma-assisted combustion and reforming, yielding unique data on plasma dynamics in ammonia and methane combustion, shock wave formation, and radical behavior. Data are now shared with modeling groups for deeper analysis
Initially, few diagnostic methods existed for controlled plasma studies, especially at atmospheric pressures. Plasma chemistry and combustion span timescales from picoseconds to milliseconds and are highly stochastic. Pulsed lasers are ideal for in-situ studies of reactive species and high-energy electrons. We developed next-generation pico- and femtosecond laser diagnostics to capture species distributions and rapid electron-driven energy transfer—key to plasma-assisted chemistry.
Our goal is to support carbon-free, net-zero fuels like ammonia. Plasma stimulation enhances combustion of varied feedstocks. Plasma conversion of CH₄/CO2 shows promise for producing H2, CO, and valuable hydrocarbons.
Conclusion of the action:
The project successfully produced numerous publications in leading journals. We developed novel optical methods to capture plasma parameters and radicals using single-shot imaging in harsh environments. These techniques enabled investigation of plasma-assisted combustion and reforming, yielding unique data on plasma dynamics in ammonia and methane combustion, shock wave formation, and radical behavior. Data are now shared with modeling groups for deeper analysis
Experimental platforms for plasma-assisted combustion and plasma reforming with non-thermal plasma have been developed. We studied how flame speed is affected by pulsed high-voltage stimulation below breakdown and how sustainable discharge plasma controls large swirl-stabilized flames. The next step used highly non-thermal plasmas, generated by ns-pulsed high voltage and current-limited high voltage, to study detailed stimulation effects on flames and gas mixtures.
In parallel, we developed laser-based spectroscopic methods to image atomic and molecular radicals, study electron properties, and perform high-speed imaging across multiple timescales to capture immediate plasma effects. These tools, along with others under development, have been applied to investigate plasma properties and plasma stimulation with high spatial and temporal resolution. We now aim to map the initial steps of high-voltage stimulation effects on various flames and gas mixtures.
Ultra-short laser pulses for imaging atom- and radical species dynamics will be further employed and results will be shared between research groups, industry partners, and at scientific conferences and in journal publications. We also collaborate with chemical kinetics modellers to integrate our findings into plasma chemical kinetics research, with the ultimate goal of understanding plasma reaction dynamics in gas mixtures and combustion processes.
Overview: The outcomes are divided into two parts:
(A) Development of state-of-the-art diagnostics:
1. 3D reconstruction of plasma discharges and radicals in turbulent, stochastic conditions.
2. High-repetition rate laser imaging of plasma-based radical dynamics.
3. Collision phenomena captured via fluorescence- and coherence lifetime imaging, including strategies for improving streak cameras.
4. Mirror-less lasing achieved in oxygen-rich volumes, promising for high-temperature plasma studies.
5. Two-photon wide-field imaging of atoms with high signal-to-noise ratios using light-amplitude control and lock-in analysis, mitigating plasma emission.
These developments enable detailed plasma studies across a broad range of timescales.
(B) Plasma phenomena and applications:
1. Plasma-assisted combustion was achieved using gliding arc and nanosecond plasma stimulation, with a focus on fundamental studies of ammonia and methane combustion under different electrode configurations. A comprehensive data bank on plasma-assisted ammonia combustion was built, covering plasma formation, rapid gas heating, shock wave generation, and radical dynamics. Plasma-assisted methane combustion was similarly investigated, revealing differences based on pulsing and electrode configurations. Modelling remains critical for fully understanding plasma-combustion interactions.
2. Plasma reforming dynamics of O2/N2 and CH₄ gas mixtures were studied using gliding arc and nanosecond plasmas. Novel findings revealed an unexpected slow buildup of oxygen atoms during nanosecond plasma formation. Hydroxyl radical distributions were characterized, suggesting strong gas heating (~4000 K) in the gliding arc. CH₃ and CH radical dynamics during CH₄ reforming displayed faster evolution compared to oxygen atoms. Data is being shared with collaborators developing plasma reforming models for CH₄ with/without CO2 and low O2 concentrations.
In parallel, we developed laser-based spectroscopic methods to image atomic and molecular radicals, study electron properties, and perform high-speed imaging across multiple timescales to capture immediate plasma effects. These tools, along with others under development, have been applied to investigate plasma properties and plasma stimulation with high spatial and temporal resolution. We now aim to map the initial steps of high-voltage stimulation effects on various flames and gas mixtures.
Ultra-short laser pulses for imaging atom- and radical species dynamics will be further employed and results will be shared between research groups, industry partners, and at scientific conferences and in journal publications. We also collaborate with chemical kinetics modellers to integrate our findings into plasma chemical kinetics research, with the ultimate goal of understanding plasma reaction dynamics in gas mixtures and combustion processes.
Overview: The outcomes are divided into two parts:
(A) Development of state-of-the-art diagnostics:
1. 3D reconstruction of plasma discharges and radicals in turbulent, stochastic conditions.
2. High-repetition rate laser imaging of plasma-based radical dynamics.
3. Collision phenomena captured via fluorescence- and coherence lifetime imaging, including strategies for improving streak cameras.
4. Mirror-less lasing achieved in oxygen-rich volumes, promising for high-temperature plasma studies.
5. Two-photon wide-field imaging of atoms with high signal-to-noise ratios using light-amplitude control and lock-in analysis, mitigating plasma emission.
These developments enable detailed plasma studies across a broad range of timescales.
(B) Plasma phenomena and applications:
1. Plasma-assisted combustion was achieved using gliding arc and nanosecond plasma stimulation, with a focus on fundamental studies of ammonia and methane combustion under different electrode configurations. A comprehensive data bank on plasma-assisted ammonia combustion was built, covering plasma formation, rapid gas heating, shock wave generation, and radical dynamics. Plasma-assisted methane combustion was similarly investigated, revealing differences based on pulsing and electrode configurations. Modelling remains critical for fully understanding plasma-combustion interactions.
2. Plasma reforming dynamics of O2/N2 and CH₄ gas mixtures were studied using gliding arc and nanosecond plasmas. Novel findings revealed an unexpected slow buildup of oxygen atoms during nanosecond plasma formation. Hydroxyl radical distributions were characterized, suggesting strong gas heating (~4000 K) in the gliding arc. CH₃ and CH radical dynamics during CH₄ reforming displayed faster evolution compared to oxygen atoms. Data is being shared with collaborators developing plasma reforming models for CH₄ with/without CO2 and low O2 concentrations.
We expect this project to advance beyond state-of-the-art in:
1. Developing a plasma discharge with distributed effects over a large gas/flame volume, enhancing plasma-processing and allowing better controlled studies.
2. Developing diagnostic methods for imaging and filming atom- and radical formation/consumption, energy distribution dynamics, and electron properties.
3. Applying these diagnostics in plasma-assisted combustion and plasma conversion to reveal early reaction dynamics.
Conclusion of the action:
The project’s diagnostic development has progressed beyond state-of-the-art through:
1. Single-shot coherence lifetime imaging (CLI) capturing molecular collision dynamics alongside CARS signal imaging.
2. A fluorescence lifetime imaging method for quantitative and qualitative PLIF investigations.
3. A tomographic method enabling 3D reconstruction of plasma discharges.
4. 2D wide-field radical imaging via two-photon laser-induced fluorescence, enhanced by light-field amplitude control (LAC) and modified lock-in analysis to improve signal quality and suppress plasma emission, allowing in-situ plasma chemistry studies.
5. A coherent laser-based method for studying plasma-produced atomic radicals.
6. Single-shot 3D imaging of radicals in plasma.
7. High-speed laser imaging of plasma-produced radical distribution dynamics interacting with flow dynamics.
8. A photofragmentation PLIF method enabling single-shot CH₃ radical distribution imaging.
Experimental key results beyond state-of-the-art:
1. Publications on radical distribution dynamics and hydrodynamics in plasma-assisted ammonia and methane combustion under ns-plasma stimulation. The ammonia PAC data is unique and the only data currently available. The methane data is among the few datasets of its kind and serves as a valuable comparison within the research community.
2. Rapid plasma chemistry data for plasma formation in oxygen, where method #4 enabled studies showing that ground-state oxygen is not primarily produced by electron collisions, challenging previous assumptions.
3. CH₃ and CH dynamics from plasma reforming of CH₄ at atmospheric conditions, providing new insights into radical behaviour during reforming processes.
All data have been shared with research groups to further the impact within the plasma-assisted combustion and plasma reforming communities.
1. Developing a plasma discharge with distributed effects over a large gas/flame volume, enhancing plasma-processing and allowing better controlled studies.
2. Developing diagnostic methods for imaging and filming atom- and radical formation/consumption, energy distribution dynamics, and electron properties.
3. Applying these diagnostics in plasma-assisted combustion and plasma conversion to reveal early reaction dynamics.
Conclusion of the action:
The project’s diagnostic development has progressed beyond state-of-the-art through:
1. Single-shot coherence lifetime imaging (CLI) capturing molecular collision dynamics alongside CARS signal imaging.
2. A fluorescence lifetime imaging method for quantitative and qualitative PLIF investigations.
3. A tomographic method enabling 3D reconstruction of plasma discharges.
4. 2D wide-field radical imaging via two-photon laser-induced fluorescence, enhanced by light-field amplitude control (LAC) and modified lock-in analysis to improve signal quality and suppress plasma emission, allowing in-situ plasma chemistry studies.
5. A coherent laser-based method for studying plasma-produced atomic radicals.
6. Single-shot 3D imaging of radicals in plasma.
7. High-speed laser imaging of plasma-produced radical distribution dynamics interacting with flow dynamics.
8. A photofragmentation PLIF method enabling single-shot CH₃ radical distribution imaging.
Experimental key results beyond state-of-the-art:
1. Publications on radical distribution dynamics and hydrodynamics in plasma-assisted ammonia and methane combustion under ns-plasma stimulation. The ammonia PAC data is unique and the only data currently available. The methane data is among the few datasets of its kind and serves as a valuable comparison within the research community.
2. Rapid plasma chemistry data for plasma formation in oxygen, where method #4 enabled studies showing that ground-state oxygen is not primarily produced by electron collisions, challenging previous assumptions.
3. CH₃ and CH dynamics from plasma reforming of CH₄ at atmospheric conditions, providing new insights into radical behaviour during reforming processes.
All data have been shared with research groups to further the impact within the plasma-assisted combustion and plasma reforming communities.