The Influence of Fuel Injection Location in Bottom‐Wall Cavity With Aft‐Wall Divergence at Supersonic Reacting Flow Field

ABSTRACT The impact of fuel injection positioning along the bottom‐wall cavity with aft‐wall divergence in a parallel‐injection, reacting flow environment has been examined through numerical analysis. This simulation employs the two‐dimensional Reynolds‐averaged Navier–Stokes equations coupled with the shear stress transport k – ω turbulence model and a single‐step reaction chemistry model for the fuel–air combustion process. Fuel injection locations at the cavity's fore wall, bottom wall, and aft wall are assessed and compared with a baseline Deutsches Zentrum für Luft‐ und Raumfahrt scramjet combustor. The analysis of numerical results based on varying fuel injection locations reveals that aft‐wall injection enhances the recirculation zone, improving fuel residence time and leading to better mixing and combustion performance. Furthermore, this configuration achieves a 20% reduction in combustor length required for complete combustion, with a 27% increase in total pressure loss due to shock waves emanating from the cavity edges, compared with the baseline model.