Numerical investigation of a hydrogen-fueled scramjet combustor at flight conditions

Numerical investigations of a hydrogen-fueled scramjet combustor at cruise flight conditions of Mach 8 at an altitude of 30 km have been performed. Two combustor configurations were investigated: a single-stage combustor with a central strut injector and a two-staged combustor combining the central strut and wall-mounted ramp injectors. These numerical simulations are aimed to study the flow structure, supersonic mixing, autoignition, and combustion for the present combustor configurations. A turbulent flow from a separate intake calculation was used as inflow condition for the combustor. A better performance for the two-staged combustor configuration was observed. The combination of the central strut injection together with the wall-ramp injection improved the turbulent mixing and, consequently, the combustion process. Inside the supersonic combustion chamber, the autoignition zone occurred downstream of the injectors, and combustion takes place accompanied by high heat release and pressure rise. As the equivalence ratio was increased, the combustion became stronger causing an upstream displacement of the shock train producing different pressure variations. For the two-staged combustor configuration, the location of the autoignition zone was found to appear further upstream compared to single-stage combustor. Mixing was improved by addition of the second-stage injection. The influence of the wall temperature was also investigated showing an effect on the combustion pressure rise and the length and location of the shock train