Impact of Intake Boundary Layer Turbulence on the Combustion Behavior in a Scramjet

The present investigations focus on the mixing and combustion enhancement capabilities of a boundary layer entering a combustion chamber. Numerical investigations for both a generic configuration and a real ramp compression intake of a full-scale vehicle with a combustion chamber height of 0.3 m were performed. The flow condition is chosen according to possible conditions in a scramjet combustion chamber with 1300-kelvin static temperature, 1-bar static pressure, and a Mach number of 3. The results of this sensitivity study show that both mixing and combustion efficiency are significantly increased due to the turbulence of the incoming boundary layer, whereas the required injector spacing to reach optimum mixing and combustion has to be increased. In addition to the classical porthole injection, an injection system with hypermixing capabilities was investigated which showed comparable sensitivities.