Project
CFD4H2 – investigation of hydrogen combustion
The growing interest in hydrogen as a clean energy carrier underscores the need for reliable tools to support safe and efficient system design. Many aspects of hydrogen combustion are still not fully understood, and experimental campaigns alone cannot cover the wide range of operating conditions and design options. CFD, therefore, is an essential instrument for exploring flame behaviour, assessing risks such as flashback, and guiding early design decisions. At the same time, modelling hydrogen combustion under application-relevant conditions demands substantial computational resources. HPC enables the required resolution, detailed chemistry treatments, and extensive parameter studies. Building on previous work, the artificially thickened flame model is extended for hydrogen, ammonia-hydrogen and methane-hydrogen blends within this project to advance CFD capabilities using HPC systems.
Project Details
Project term
November 3, 2024–November 2, 2025
Affiliations
TU Darmstadt
Institute
Institute for Simulation of reactive Thermo-Fluid Systems
Principal Investigator
Methods
The project combines fundamental studies of hydrogen combustion with model development and their transfer to technical configurations. The methodology centres on resolving and modelling turbulence–chemistry interaction, particularly the sub-grid flame behaviour affected by hydrogen’s strong diffusivity and the resulting thermodiffusive effects. This mechanism, which increases local flame speeds and surface wrinkling, is not yet represented in current modelling strategies. To address this, laminar DNS and turbulent LES are carried out with an extended OpenFOAM solver using detailed chemistry. Laminar cases provide the basis for new model parameters, which are then tested under turbulent conditions and validated against lab-scale burner data. The same framework is applied to hydrogen–methane and hydrogen–ammonia blends to assess how hydrogen-specific effects influence flame structure and model performance.
Results
During the project phase, a wide range of flame configurations was successfully simulated, creating a strong foundation for model development. Two-dimensional freely propagating hydrogen flames were examined across multiple domains and thickening factors, allowing the derivation of an extended artificially thickened flame model. This formulation showed good agreement with fully resolved reference simulations and was validated a posteriori under fixed conditions before being published. Additionally, the model was broadened for multi-step chemistry and more general operating regimes using a DNS dataset exceeding 200 simulations. When applied to a turbulent jet flame, the generalized model substantially improved predictions of fuel consumption speed across varying operating conditions and was published and presented internationally.
Discussion
The extended modelling framework demonstrates that incorporating hydrogen-specific diffusion effects is essential for accurately predicting flame behaviour in both laminar and turbulent regimes. The improved performance of the novel model in turbulent jet flames highlights its ability to capture enhanced fuel-consumption rates driven by preferential and differential diffusion, which are neglected in standard models. Additional investigations of laminar hydrogen Bunsen flames, performed in both 2D and 3D, revealed stronger flashback tendencies when thermal diffusion was included. The emergence of three-dimensional cellular flame structures significantly altered local flame acceleration and instability development, underscoring the limitations of reduced-dimensional studies. These observations confirm the need for high-fidelity modelling and provide important guidance for further refining turbulence–chemistry interaction models for hydrogen and hydrogen-blend combustion.
Additional Project Information
DFG classification: 404-03 Fluid Mechanics
Software: OpenFOAM
Cluster: CLAIX
Publications
Vinzenz Schuh, Driss Kaddar, Antonia Bähr, Mathis Bode, Christian Hasse, Hendrik Nicolai,
An Extended Artificially Thickened Flame Model for Turbulent Hydrogen and Hydrogen-Enriched Flames With Intrinsic Instabilities Under Gas Turbine Relevant Conditions
https://dx.doi.org/10.1115/GT2025-152452, June 2025
Vinzenz Schuh, Driss Kaddar, Antonia Bähr, Mathis Bode, Christian Hasse, Hendrik Nicolai,
An Extended Artificially Thickened Flame Model for Turbulent Hydrogen and Hydrogen-Enriched Flames With Intrinsic Instabilities Under Gas Turbine Relevant Conditions
https://dx.doi.org/10.1115/1.4069549, August 2025
Vinzenz Schuh, Christian Hasse, Hendrik Nicolai,
An extension of the artificially thickened flame approach for premixed hydrogen flames with intrinsic instabilities
https://dx.doi.org/10.1016/j.proci.2024.105673, July 2024