Numerical investigation on implication of innovative hydrogen strut in comparison with multi strut injector on performance and combustion characteristics in a scramjet combustor

Detailed numerical analysis on a cavity-based scramjet combustor is carried out by introducing an innovatively shaped strut and multi strut with backward-facing step to generate intense vorticity, which helps in efficient mixing of fuel and oxidizer. In this study, the flow dynamics with finite volume approach on commercial software Ansys-Fluent 20.0 to solve the compressible two-dimensional fluid flow with RANS equation by considering the density-based solver with SST k- ω turbulent model. The species transport model with volumetric reaction and finite rate/eddy dissipation turbulence chemistry interaction is adopted to study the combustion phenomena. Numerically calculated results are validated with its corresponding experimental results by comparing pressure distribution along the length of the combustor, distribution of H₂ mole fraction for different axial locations of combustors, and it is found that the interaction of the shear shock layer enhances the mixing rate by intensifying turbulence. It is found that the multi strut improves the mixing and combustion efficiency compared with that of the single strut owing to the formation of a significant separation layer, resulting in multiple shocks, vortices, and a larger recirculation zone.