HIGH FIDELITY SIMULATION OF A PROTOTYPE HYDROGEN BURNER CONCEPT

With the global energy transition underway, hydrogen is emerging as a promising alternative fuel for a wide range of combustion applications due to its carbon-free combustion. In the context of gas turbine combustion, this thesis investigates the high-fidelity simulation of a prototype Dry Low Emissions (DLE) hydrogen burner with a Micromix combustor design and Jet-in-Crossflow (JICF) injection. The study began with a comprehensive review of hydrogen combustion technologies and of the emissions advantages and challenges of this element, focusing, in particular, on NOₓ formation. A CFD-based numerical model of a single burner unit was developed in ANSYS Fluent, examining various turbulence and combustion models including RANS, URANS, LES, and hybrid RANS/LES for turbulence, EDM, ED-FR and EDC for combustion, as well as detailed and reduced chemical kinetics. A thorough mesh independence study was performed, followed by simulation campaigns using different modelling strategies to evaluate flame stability, temperature profiles, and NOₓ pollutant formation. Experimental data from a dedicated test rig were used for partial validation of the numerical results. The findings highlighted the sensitivity of the NOₓ formation predictions to the mesh refinement and turbulence-chemistry interaction, with a higher degree of dependency on the turbulence models. The optimized mesh and the more detailed models demonstrated improved agreement with experimental data and with the behaviour of the combustion predicted by the literature, confirming the potential of the JICF Micromix concept for low-emission hydrogen combustion. The study also highlighted the suitability of different turbulence model for different designs applications.