Numerical Analysis of Transverse Fuel Injection at Various Angles from the Strut Base for a Hydrogen-Fuelled Scramjet Combustor

Scramjets are advanced air-breathing propulsion systems developed for hypersonic flight, allowing vehicles to reach speeds greater than Mach 5. In these engines, combustion occurs under supersonic conditions, resulting in extremely brief reaction times that challenge the efficiency of air-fuel mixing and combustion. This study looks at how angled fuel injection might improve mingling and combustion capability in a strut-based scramjet engine. The research focuses on varying the angles of fuel injection, both upstream and downstream, through numerical simulations. The simulations employ a 2-D Reynolds-Averaged Navier-Stokes (RANS) equation framework coupled with finite rate/eddy dissipation and the Shear Stress Transport (SST) k-ω turbulence model using a density-based solver with finite volume discretization. When the results are compared, they show that the 30-degree and 60-degree inclined injections slow down the flow by 40% and 60%, respectively, in the strut wake region. This enhances the air-fuel mixing and combustion efficiency by expanding the recirculation area. Overall, the 60-degree injection technique achieves 100% mixing efficiency at a distance of 140 mm, which is 30 mm from a fuel injector. Parallel injection achieves 100% mixing efficiency at a distance of 230 mm, which is 120 mm from a fuel injector. This study shows that angled fuel injection could help improve the performance of scramjet combustor systems when they are operating at hypersonic speeds.