Numerical simulation of hypersonic shock-induced combustion ramjets

Hypersonic air-breathing propulsion utilizing: shock-induced combustion ramjets is investigated, Two-dimensional geometries are simulated with planar and axisymmetric configurations, as well as external and mixed-compression configurations. The lower-upper Symmetric Gauss-Seidel scheme combined with a symmetric shock-capturing total variation diminishing scheme are used to solve the Euler equations, with nonequilibrium chemical reactions. The finite rate chemistry model includes 13 species (H-2, O-2, H, O, OH, H2O, HO2, H2O2, N, NO, HNO, N-2) and NO2) and 33 reactions. The numerical method has been verified by comparison with H-2/air induction delay times, analytical solutions to wedge problems, and exothermic blunt body flows. Results obtained with an inviscid, chemically nonequilibrium numerical approach and with realistic geometries demonstrate that shock-induced combustion can be used as a viable means of hypersonic propulsion. As part of the combustor design, it has also been numerically demonstrated that a minimum-entropy, or Chapman-Jouguet condition exists for oblique-detonation waves generated by wedges in nonequilibrium chemically reacting H-2/air flowfields.