Experimental comparison of additively manufactured premixed hydrogen burners using optical diagnostics

Premixed hydrogen combustion is increasingly important as a technology for decarbonizing high-temperature industrial processes. The design flexibility enabled by additive manufacturing provides new opportunities to realize complex burner geometries that are difficult or impossible to produce with conventional methods. By coupling it with geometry optimization based on numerical simulations, the development of burners with increased stability, extended fuel and power flexibility, and reduced pollutant emissions becomes possible. In this study, three different modular burner nozzle designs are systematically compared with respect to these optimization targets using a newly developed diagnostic framework. Distinct differences between the nozzle configurations are identified in terms of their operational range, as characterized by flame stability maps. Simultaneous OH and CH 2 O planar laser-induced fluorescence (PLIF), in combination with OH* chemiluminescence measurements, are employed to analyze the main location of heat release. Complementary infrared measurements of both the nozzle and the flame temperature (at a fixed location in the flames) reveal strong correlations between flame stability characteristics, heat release location, and a possible feedback into the nozzle material. We conclude that these mainly result from the difference between the local mixture distribution of the nozzles. Based on this experimental framework, the characterization and evaluation of optimized design geometries become possible.