Session: 04-24 Combustion - Modeling II

Submission Number: 179330

Joint Experimental and Numerical Investigation of a Multi-Fuel Hydrogen-Kerosene Burner Developed Within the Hope Project 

The transition toward carbon-neutral aviation has accelerated research on sustainable propulsion systems and alternative fuels, with hydrogen emerging as a leading candidate due to its zero direct carbon emissions. However, pure-hydrogen operation remains challenging and is still far from being fully implemented or understood. To smooth the transition toward 100% hydrogen operation, multi-fuel combustion strategies—burning gaseous hydrogen and liquid kerosene simultaneously—represent a promising transitional pathway that can already be pursued in the coming decades. This approach enhances flame stability under lean conditions and reduces CO₂, NOₓ, and soot compared with pure kerosene, offering a practical transitional route toward hydrogen-powered aviation.

Within this framework, a novel multi-fuel burner was developed under the Horizon Europe HOPE (Hydrogen Optimized multi-fuel Propulsion system for clean and silEnt aircraft) project. The burner integrates an axial simplex atomizer for kerosene, a radial air swirler for stabilization, cross-flow hydrogen injection for efficient premixing, and Axial Air Injection (AAI) to prevent flashback. Preliminary atmospheric experiments using flame imaging revealed the flame topologies from 100% kerosene to 100% hydrogen and all intermediate blends. Crucially, the burner proved capable of operating stably across the entire range of hydrogen–kerosene mixtures without exhibiting instabilities or other operational issues. Further investigations is ongoing to identify the optimal operating conditions in terms of emissions reduction and flame stability.

Complementary CFD simulations employ a modified Thickened Flame Model (TFM) with two-dimensional look-up tables for laminar flame speed and thickness as functions of equivalence ratio and hydrogen–kerosene ratio. This extension enables the model to handle multi-fuel combustion regimes within a unified framework. Scale-resolving simulations successfully reproduce the experimentally observed transition in flame structure across fuel blends. Moreover, the CFD analysis complements the experiments by providing valuable insights into the mixing process between the two fuels, contributing to a more comprehensive understanding of their interaction. Nonetheless, this represents only a preliminary validation, and further model development and experimental comparison are required.

This work presents the first joint experimental and numerical assessment of hydrogen–kerosene multi-fuel combustion within the HOPE project. The results demonstrate the feasibility of the burner concept and the potential of the extended TFM formulation to capture key multi-fuel flame features. This work represents an intermediate step toward a comprehensive characterization of the HOPE combustor, which will include advanced diagnostics such as reacting PIV, OH* chemiluminescence, OH-NO PLIF and detailed emissions measurements for further validation of numerical models and design refinement.

Presenting Author: Lorenzo Mazzei Ergon Research

Presenting Author Biography: Lorenzo Mazzei is a CFD Engineer and R&D Program Manager at Ergon Research, where he provides CFD-based solutions for the development of innovative products. He works in the sectors of aviation, power-gen, oil&gas, automotive and renewables, improving the design in fluid, heat transfer, combustion and thermal management applications. In the past he carried out his PhD and PostDoc at the University of Florence, working on industrial and European research projects for the aerothermal design of combustors and turbines.

Authors:

Lorenzo Palanti Ergon Research
Lorenzo Mazzei Ergon Research
Cosimo Bianchini Ergon Research
Alam Garcidueñas-Correa TU Delft
Kaushal Dave TU Delft
Arvind Gangoli Rao TU Delft
Francesca De Domenico TU Delft