The non-reacting flow characteristics of pylon and wall injections in a dual combustion ramjet engine

The influence of pylon and wall injection in coaxial jets of a Dual Combustion Ramjet engine is numerically investigated in a non-reacting flow field. The supersonic combustor is modeled and analyzed using the commercial CFD software ANSYS 18.0. The three-dimensional compressible Reynolds-averaged Navier-Stokes (RANS) equations coupled with the SST k-omega turbulence model have been used to analyze the coaxial mixing characteristics of the jets. The numerical study is validated with the experimental data of the wall static pressures measured in the combustor's flow direction. The pylon and wall injectors are located symmetrically at the gas generator's exit nozzle, and the air is used as the injectant to simulate gaseous fuel. Three injection pressures are used for the study to understand the flow field characteristics in the injector regime. Also, the gas generator downstream direction is investigated. The shock waves generated from the gas generator nozzle enhance the mixing of the coaxial jets with minimum total pressure loss. The shock wave interactions are noticed with reducing intensity within the supersonic combustor for pylon injection, leading to higher total pressure loss than the wall injection. The pylon injection provides the spatial distribution of fuels compared to the wall injection in the coaxial supersonic flow field.