Periodic Reporting for period 1 - ICHAruS (Investigation and Control of Hydrogen flames Across the Scales)
Berichtszeitraum: 2023-10-01 bis 2025-09-30
This project develops physics-based control concepts for hydrogen combustion using external electric and magnetic fields and non-thermal plasma. Experiments and simulations indicate that electromagnetic actuation can promote ignition, stabilize lean flames, and mitigate thermoacoustics through ionic wind, plasma-generated radicals, and localized energy deposition, but industrial adoption is limited by the lack of validated multi-scale predictive tools. The project builds an integrated multi-scale framework linking plasma physics to continuum combustion modelling by combining reactive molecular dynamics, 0D/1D plasma–combustion solvers, turbulence-resolving DNS, and targeted experiments. Atomistic studies quantify field effects on kinetics and transport and support physically consistent charge modelling. Plasma-assisted solvers capture electron-driven chemistry and energy transfer and provide CFD-ready reduced source terms, while DNS and experiments deliver high-fidelity datasets and measurements of flame response and thermoacoustic behaviour under static and time-modulated fields.
Expected impacts include more reliable ignition and lean-flame stabilization, improved thermoacoustic control, and higher flexibility and efficiency of hydrogen combustors, supported by validated tools, open modelling frameworks, and reference datasets that accelerate industrial innovation and Europe’s clean-energy goals.
Expected impacts include more reliable ignition and lean-flame stabilization, improved thermoacoustic control, and higher flexibility and efficiency of hydrogen combustors, supported by validated tools, open modelling frameworks, and reference datasets that accelerate industrial innovation and Europe’s clean-energy goals.
During the reporting period, the project delivered coordinated theoretical, numerical, and experimental progress on hydrogen combustion under external electromagnetic fields and non-thermal plasma, following a multi-scale, multi-physics strategy from atomistic modelling to flame-scale solvers, DNS, and laboratory validation.
At the atomistic scale, reactive molecular dynamics was used to quantify electric-field effects on hydrogen combustion chemistry and to assess the role of charge equilibration. A systematic comparison of QEq-based methods, QTPIE, and the physically grounded ACKS2 scheme showed that commonly used approaches can produce unphysical long-range charge transfer and artificially enhanced reaction rates under applied fields. ACKS2 provided more realistic charge distributions and molecular neutrality, establishing methodological guidance for reliable MD studies and clarifying the physical interpretation of field effects.
At the kinetic/PAC scale, the zero-dimensional ChemPlasKin framework was analysed, validated, and improved to strengthen the coupling between electron kinetics and combustion chemistry. Validation against literature H2/O2 cases confirmed correct prediction of ignition delay, radical production, and electron-driven excitation. Numerical robustness was improved by introducing measures to avoid instabilities and unphysical overheating (including extended post-ignition integration and improved energy-deposition control), and a sensitivity study on EEDF update criteria identified key controlling parameters.
A 1D steady-state plasma-assisted flame solver (PlasmaStFlow) was developed by extending Cantera’s StFlow formulation. The solver couples detailed combustion chemistry with non-equilibrium plasma kinetics via a Boltzmann solver to compute electron-impact reactions and plasma energy deposition self-consistently. It was validated in no-plasma conditions with excellent agreement against standard Cantera solutions. Initial plasma-activated simulations reproduced expected trends but revealed stiffness at high reduced electric fields, motivating targeted developments such as adaptive continuation and localized field activation. The main outcome is a functional, physically consistent 1D PAC tool that bridges plasma kinetics and flame-scale modelling and provides a pathway toward CFD-compatible reduced models.
On the experimental side, a dedicated platform was established to study electromagnetic interactions in premixed laminar hydrogen flames, including a burner and electrode configuration optimized via electrostatic simulations. The setup enables static and time-modulated electric fields combined with acoustic forcing. Flame response was measured using velocity diagnostics and OH* chemiluminescence, allowing the derivation of Flame Transfer Functions (FTF) and Flame Describing Functions (FDF). First results quantified the sensitivity of gain and phase to forcing amplitude, providing a baseline for future electro-acoustic coupling studies and model validation.
At the turbulence-resolving scale, a multi-physics DNS framework was extended to include electromagnetic body forces and magnetic-field effects in reacting-flow solvers. Governing equations and force models were implemented and verified, and code optimisations reduced computational cost without compromising accuracy. Initial simulations produced detailed fields of electromagnetic forcing and its interaction with flame structure, generating high-fidelity datasets to inform reduced modelling.
Finally, complementary work investigated nanosecond repetitively pulsed (NRP) discharges in hydrogen-reactive environments. High-resolution fluid simulations of streamers under temperature and density gradients representative of flames quantified acceleration, energy-deposition patterns, and discharge–flame interactions. These results provide physically consistent inputs and datasets for phenomenological plasma models and for future LES/RANS implementations of plasma-assisted combustion.
At the atomistic scale, reactive molecular dynamics was used to quantify electric-field effects on hydrogen combustion chemistry and to assess the role of charge equilibration. A systematic comparison of QEq-based methods, QTPIE, and the physically grounded ACKS2 scheme showed that commonly used approaches can produce unphysical long-range charge transfer and artificially enhanced reaction rates under applied fields. ACKS2 provided more realistic charge distributions and molecular neutrality, establishing methodological guidance for reliable MD studies and clarifying the physical interpretation of field effects.
At the kinetic/PAC scale, the zero-dimensional ChemPlasKin framework was analysed, validated, and improved to strengthen the coupling between electron kinetics and combustion chemistry. Validation against literature H2/O2 cases confirmed correct prediction of ignition delay, radical production, and electron-driven excitation. Numerical robustness was improved by introducing measures to avoid instabilities and unphysical overheating (including extended post-ignition integration and improved energy-deposition control), and a sensitivity study on EEDF update criteria identified key controlling parameters.
A 1D steady-state plasma-assisted flame solver (PlasmaStFlow) was developed by extending Cantera’s StFlow formulation. The solver couples detailed combustion chemistry with non-equilibrium plasma kinetics via a Boltzmann solver to compute electron-impact reactions and plasma energy deposition self-consistently. It was validated in no-plasma conditions with excellent agreement against standard Cantera solutions. Initial plasma-activated simulations reproduced expected trends but revealed stiffness at high reduced electric fields, motivating targeted developments such as adaptive continuation and localized field activation. The main outcome is a functional, physically consistent 1D PAC tool that bridges plasma kinetics and flame-scale modelling and provides a pathway toward CFD-compatible reduced models.
On the experimental side, a dedicated platform was established to study electromagnetic interactions in premixed laminar hydrogen flames, including a burner and electrode configuration optimized via electrostatic simulations. The setup enables static and time-modulated electric fields combined with acoustic forcing. Flame response was measured using velocity diagnostics and OH* chemiluminescence, allowing the derivation of Flame Transfer Functions (FTF) and Flame Describing Functions (FDF). First results quantified the sensitivity of gain and phase to forcing amplitude, providing a baseline for future electro-acoustic coupling studies and model validation.
At the turbulence-resolving scale, a multi-physics DNS framework was extended to include electromagnetic body forces and magnetic-field effects in reacting-flow solvers. Governing equations and force models were implemented and verified, and code optimisations reduced computational cost without compromising accuracy. Initial simulations produced detailed fields of electromagnetic forcing and its interaction with flame structure, generating high-fidelity datasets to inform reduced modelling.
Finally, complementary work investigated nanosecond repetitively pulsed (NRP) discharges in hydrogen-reactive environments. High-resolution fluid simulations of streamers under temperature and density gradients representative of flames quantified acceleration, energy-deposition patterns, and discharge–flame interactions. These results provide physically consistent inputs and datasets for phenomenological plasma models and for future LES/RANS implementations of plasma-assisted combustion.
The project delivered a multi-scale set of results that advances the understanding and modelling of hydrogen combustion under external electromagnetic fields and non-thermal plasma. By integrating atomistic simulations, plasma-assisted combustion modelling, high-fidelity DNS, and controlled experiments, it addressed key uncertainties that limit reliable hydrogen combustor deployment. At the molecular level, it showed that common charge-modelling assumptions can yield unphysical behaviour under electric fields and identified more physically consistent approaches for charge redistribution and transport, improving the robustness of plasma–combustion simulations. The project produced validated tools for physically consistent plasma-assisted hydrogen combustion: an improved 0D solver for electron-driven chemistry and energy deposition, and a new 1D steady-state solver linking non-equilibrium plasma kinetics to continuum combustion. These tools provide transferable datasets and source terms suitable for reduced-order models and CFD integration. DNS capabilities were also extended to include electromagnetic forcing, generating high-fidelity data on field effects on flame structure, transport, and stability in laminar and turbulent regimes.
Experimental work provided essential validation through dedicated laminar burners and optimized electrode configurations. Measurements of flame transfer and describing functions quantified hydrogen flame response under combined acoustic and electric forcing, offering a benchmark for electromagnetic control of thermoacoustic instabilities in lean operation.
Experimental work provided essential validation through dedicated laminar burners and optimized electrode configurations. Measurements of flame transfer and describing functions quantified hydrogen flame response under combined acoustic and electric forcing, offering a benchmark for electromagnetic control of thermoacoustic instabilities in lean operation.