Numerical Studies on the Flame Structures and Combustion Performance of Supersonic Turbulent Combustion in DCR

A numerical study was carried out to investigate the flame structures and combustion performance of supersonic turbulent combustion in a dual combustion ramjet (DCR) engine.A multidimensional fifth-order high-resolution scheme was used to capture the fine-scale turbulence eddy dynamics.Two series of numerical experiments were carried out for the DCR combustors: one with various divergence angles and the other with different lengths of the constant-area combustor section.The operating conditions were selected by considering the flight conditions.The turbulent flame structure and combustion performance were analyzed according to the scalar dissipation rate and other flow parameters.Two different combustion modes were found according to the formation of Mach reflection, which reduces the scalar dissipation rate.The dynamic characteristics of combustion were investigated by the variation of wall pressure and other properties.The critical conditions for combustion stabilization were determined from the coupling of pressure waves interacting with turbulent combustion.The results show that the shock compression and turbulent combustion support each other, similarly to detonation phenomena.