Numerical Simulation of Hypersonic Shock-Induced Combustion Ramjets

Hypersonic air-breathing propulsion utilizing shock-induced combustion ramjets is investigated. Twodimensional 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 (H2, O2, H, O, OH, H2O, HO2, H2O2, N, NO, HNO, N2, and NO2) and 33 reactions. The numerical method has been verified by comparison with H2/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-entrop y, or Chapman-Jouguet condition exists for oblique-detonation waves generated by wedges in nonequilibrium chemically reacting H2/air flowfields.