Experimental investigation of low-NOx H₂ combustion using simultaneous Raman and LIF spectroscopy

The global push toward decarbonization has positioned hydrogen as a key contender for clean energy applications. This study explores low-NO_x hydrogen/air combustion in a lifted flame configuration using simultaneous 1D Raman and OH-LIF spectroscopy. High resolution measurements of temperature and species concentrations (H₂, O₂, and OH) provide crucial information on the structure of the flame and the stabilization mechanisms within a dual-swirl burner. The results reveal distinct inner and outer reaction fronts, each exhibiting unique combustion behaviors due to differences in gas composition, temperature, turbulence levels, and strain rates. The study focuses on the dynamics of the edge flame at the base of the outer reaction front, where air and hydrogen progressively mix along the flow axis. Detailed analysis of flow structure, flame dynamics, and properties at key locations highlights the interplay between flow and combustion processes. These findings provide a unique experimental data set for understanding the fundamental characteristics of swirled H₂ flames, validating numerical models, and guiding the development of optimized low-NO_x H₂ combustion systems.