Abstract 

Hydrogen is widely regarded as a key enabler for decarbonizing hard-to-electrify sectors such as gas turbines, aviation, and heavy industry. While its combustion produces no carbon dioxide, the high flame temperatures associated with hydrogen lead to significant emissions of nitrogen oxides (NOx), a class of regulated pollutants with serious environmental and health impacts. Understanding and controlling NOx formation in practical hydrogen combustion systems requires detailed, spatially resolved measurements of flame structure, temperature, species composition, and pollutant concentrations under realistic operating conditions. This thesis presents a quantitative experimental investigation of confined, swirl-stabilized hydrogen flames using simultaneous Raman scattering and laser-induced fluorescence (LIF) diagnostics, spanning multiple stabilization regimes and pressures up to 6 bar.