Fuel injection location studies on pylon-cavity aided jet in supersonic crossflow

The current study numerically investigates the effect of fuel injection locations within a pylon-cavity aided Supersonic Combustion Ramjet (SCRAMJET) combustor on mixing enhancement, flame holding, fuel jet penetration and total pressure loss. RANS equations for compressed real gas are solved by coupled, implicit, second-order upwind solver. Two-equation SST model is used for turbulence modelling. The computational model is validated using experimental steady wall pressure data and 2D velocity field. The study uses seven distinct sonic fuel injection location cases of hydrogen fuel through a 1 mm diameter hole along the axis of the test section floor. All cases maintain crossflow of Mach number 2.2. The simulations show that the counter rotating vortex pair within the cavity plays a vital role in fuel dispersion and fuel jet penetration capability. The presence of pylon resulted in an increase of pressure loss by 7%, whereas the influence on total pressure loss due to transverse fuel injection is found to be insignificant. The injection locations within the cavity give around 55% (max) increase in fuel dispersion compared to location upstream of the pylon. Also the cavity floor locations give about 55% - 90% more flammable plume area than the injection from other locations. (C) 2019 Elsevier Masson SAS. All rights reserved.