Characterization of Stratified Hydrogen Flames: Implications for Burner Design

To ensure efficient and safe combustion of hydrogen, novel burner designs are required. Additive Manufacturing enables the fabrication of complex geometries that can be leveraged to develop compact hydrogen burners. To meet various power demands, array configurations of multiple nozzles offer a promising route toward scalable and flexible combustors that can be tailored to specific applications. However, the design of additively manufactured burners for operation with hydrogen poses unique challenges due to the intricate interplay of fluid dynamic, thermal, and manufacturing constraints. This work investigates two additively manufactured nozzle designs that differ in the partially premixed mixture at their nozzle outlet. Their performance is analyzed under fuel lean conditions across a range of power outputs using experimental measurements and numerical simulations, leveraging the complementary strengths of each approach. The simulations provide detailed insights into internal mixing processes that are difficult to observe otherwise. Both experiments and simulations are used to examine flame morphologies. Flashback limits are determined experimentally, revealing notable differences between the two burner designs. A detailed numerical analysis of the mechanisms driving these differences is carried out and based on the findings we draw conclusions for the design of additively manufactured burners.