Experimental Investigation of Strut Injectors for Hydrogen/Air Combustion at Atmospheric Pressure in Non-Reactive and Reactive Conditions

Abstract This study focuses on the development of strut fuel injectors for H2/air combustion in aircraft engines. A reference architecture was first studied under non-reactive conditions. Optical acetone-PLIF measurements were used to determine the progress of fuel/air mixing close to the injector outlet and the relationship to the momentum flux ratio. The injector was then tested in an academic burner at atmospheric pressure to investigate its combustion performance. A combination of OH* chemiluminescence and NOx measurements using an exhaust sampling probe demonstrated good performance in terms of flame stability and low NOx emissions over a wide range of equivalence ratios. However, the flame length was not satisfactory. To overcome this limitation, strut injectors with novel architectures were developed. OH-PLIF measurements have revealed major improvements in the fuel/air mixture, leading to a significant enhancement in the flame length and flame stabilization, as well as a near-total mitigation of NOx emissions.