Numerical investigations on the implication of hydrogen fuel jet injection pressure on the performance characteristics in a multi-strut in a double-dual cavity-based scramjet combustor

•The influence of innovative multi strut with dual cavity on scramjet combustor is investigated.•Innovative strut aids in generating intense vorticity which helps in efficient mixing of fuel and oxidiser.•Combustion efficiency was higher with innovative strut in comparison with base strut.•Shear shock layer enhances the mixing rate by intensifying turbulence phenomena.•Total pressure loss in base strut is 10% lower than that of modified strut. To analyze the influence of flow physics and operating parameters (i.e., injection pressure (2, 4, 6, and 8 bars), a simulation is performed on a scramjet combustor (modified) using the shear stress transport (SST) k- ω turbulence model and Reynolds Averaged Navier Stokes (RANS) equations. Wall pressures, the pattern of shock-wave, and static temperature of the combustor are three major parameters that have been analyzed in this study. An acceptable range of results indicates that the simulation approach adopted can be used for additional studies. According to the results of this study, the shock-wave position is destabilized when the hydrogen jet pressure is enhanced by varying the flame characteristics. Moreover, it was also observed that the shock wave travels upstream due to the pressure exerted by the main flow. A normal shock wave moves ahead of the strut as soon as the pressure in the hydrogen jet increases to 4 bar. According to this study, it is beneficial to have lower hydrogen jet pressures in supersonic flows for the geometry considered. The penetration depth of fuel in the axial direction increases, which deteriorates the combustion efficiency with an increase in the total pressure losses.