Effect of hydrogen jets in supersonic mixing using strut injection schemes

Abstract The prevalence of complex phenomena associated with the fuel mixing of a supersonic stream in scramjet combustor is inherently occurred due to the short residence time. An efficient injection mechanism is required to enhance the mixing and improve combustion efficiency. This numerical simulation study aims to reveal the performance of modified strut injection strategies within a Mach 2.0 flow field. Two-dimensional steady and transient Navier-Stokes computations of the DLR scramjet experiment is performed for various strut injection locations. The Reynolds Averaged Navier Stokes equation with the SST k-e turbulence model is utilized to solve the flow field under steady conditions. The critical parameters examined to investigate steady solutions are wall static pressure, flow Mach number, and total pressure loss across the combustor. The dual injection configuration in the flow considerably reduces the shock waves impact at the downstream of the strut and preserves the magnitude of internal forces acting on combustor walls and total pressure loss. Unsteady Detached Eddy Simulation (DES) results for hydrogen concentration and velocity field are analyzed by applying Dynamic Mode Decomposition (DMD). Multiple injections are observed to alter the frequency and the number of dominant modes.