Abstract In recent years, the potential of hydrogen as an alternative fuel for aviation decarbonization has been widely recognized by the scientific and industrial combustion communities. Due to its high reactivity and diffusion, the development of new technologies or the improvement of existing ones to safely and efficiently burn hydrogen, presents significant challenges. Furthermore, nitrogen oxides (NOx) formation is potentially enhanced, becoming one of the primary factors to address. In this study, a novel 100% hydrogen burner for aero engine applications is designed. The burner realizes a lean, nonpremixed, swirl-stabilized flame achieved with a coaxial triple swirler injector. The innermost channel supplies the fuel, while the two outer channels provide primary and secondary air injections. The injector's flow split and swirl numbers are individuated exploiting numerical results from Reynolds-Averaged Navier-Stokes (RANS) reactive calculations of a simplified geometry, allowing the down-selection of a promising design point. An iterative procedure involving more detailed RANS calculations leads to the final injector design. The burner is completed with an effusion cooling plate for the dome surface, and validated with a reactive Large Eddy Simulation (LES). The entire workflow is carried out under representative engine operating conditions. Additionally, a LES calculation is performed on a scaled version of the burner operated at ambient pressure, in the perspective of the experimental campaign that will take place at Laboratory of Technology for High-Temperature (THT-Lab) of the University of Florence, with numerical results supporting the test rig commissioning.
Ballotti et al. (Wed,) studied this question.