Effect of inclined fuel injection in the strut wake region for a hydrogen fueled scramjet combustor

The supersonic airflow and injected fuel stream mixing process is complicated for a scramjet combustor because of little supersonic air resident time and high airflow stream momentum. The direction of fuel injection into a supersonic airflow stream plays a sig-nificant role in mixing enhancement with turbulence generation. This study investigates the effect of strut-based parallel (primary) and inclined fuel injection in the strut flame holder wake region. The primary strut with parallel injection is derived from the open literature. The base model strut consists of parallel injection, whereas in the new models, the fuel is injected at an angle of q for both the upward and downward directions. By computing the Reynolds averaged Navier-Stokes equations, finite-rate eddy dissipation turbulence chemistry, and SST k -u turbulence models, the mixing and combustion behavior for various fuel injections were investigated. The impact of different fuel in-jections on the downstream wake region is assessed by evaluating the distribution of H2 and H2O species in the radial and axial directions. The turbulence intensity and turbulent kinetic energy are also considered to evaluate the cross-impact of the air stream and fuel stream for inclined fuel injection. Numerical results found that inclined injection signifi-cantly impacts the mixing phenomenon with the development of enriched re-circulation zones in the vicinity of the flame keeper. The mixing and combustion efficiencies perfor-mance parameters are evaluated for different fuel injection schemes and found the average increased mixing efficiency of 13% and combustion efficiency of 12%, respectively, for inclined fuel injection. From the analysis of mixing efficiency, it is observed that complete mixing has been found after 235 mm, whereas for inclined injection, the com-plete mixing happened within a 175 mm distance. The maximum of 75% and 62% com-bustion efficiency has been observed at a 225 mm and 285 mm distance for inclined and parallel fuel injection, respectively.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.