The work described in the HELIOS project has been divided into 6 work packages, of which WP2-5 focus on technical and scientific aspects. The key achievements in this reporting period are:
WP2: Hydrogen Combustion Fundamentals. Key technical developments in hydrogen combustion research achieved by WP2 include:
• A model burner made of quartz-glass was designed, built and successfully tested at TU Delft’s combustion laboratory.
• The preferential diffusion model applied to the laminar 2-D thermos-diffusive unstable flames is published in Combustion and Flame (Schepers, van Oijen, Comb. Flame, 2025).
• Steady state flame simulation of the simplified FlameSheetTM combustor shows reasonable agreement with experimental data
• A preferential diffusion model is successfully implemented in a rather complex case: a 3-dimensional turbulent channel flow
• First flash back results have been presented numerically as well as experimentally. However, the validation between numerical work and experimental work still needs to be performed.
WP3: FlameSheet™ Combustor Development. This WP focused on advancing the design and optimization of the FlameSheet™ combustor for high-H2 gas turbine combustors at high firing temperatures. Major outcomes include:
• Redesigned, optimized, manufactured FlameSheet™ combustor components focussing increased firing temperatures using new combustor design concepts.
WP4: High Hydrogen System Engineering and Measurement Techniques. Notable advancements in system engineering and measurement techniques:
• Established Comprehensive Safety Framework for Hydrogen Systems. Developed engineering principles and stricter safety practices addressing hydrogen’s unique challenges—such as embrittlement, leakage, detection, and fire behaviour—across the entire system lifecycle.
• Defined Critical Design and Operational Measures.
• Achieved a significant performance increase of the system which, through computer vision, is able to detect and measure flame pulsations due to combustion instabilities.
• Successful test of a combined UV-N-IR optical lens system for HELIOS HP test rig configurations
• Further development of fast-online OH* data visualization tool (“Dashboard”) with integrated analysis functions (modal decomposition, post-processing, movie creation)
• Design of a modified cooling jacket and respective optical arrangement for observation of axial hydrogen flame dynamics
WP5: FlameSheet™ Combustor Testing. Significant accomplishments in testing the FlameSheet™ combustor at high pressures include:
• Successful executed a high pressure measurement campaign at DLR using the FlameSheet™ combustor and record data at current B/E-Class like conditions with specific attention on the limiting factors regarding NOx formation, flashback and combustion instabilities
• Successfully tested increased firing temperature with new combustor design concepts.
• First demonstration of successful start-up on 100% H2, needs further development to ensure robust and safe operation.
• Significant NOx reduction achieved through premixer optimization
• First demonstration of successful ramp-up on 100% H2, needs further development to ensure robust and safe operation.
These achievements collectively advance HELIOS toward its goals, with continued emphasis on open communication, technical innovation, and strategic outreach.
