NUMERICAL-SIMULATION OF HYPERSONIC SHOCK-INDUCED COMBUSTION RAMJETS

Hypersonic air-breathing propulsion utilizing: shock-induced combustio n ramjets is investigated, Two-dimensional geometries are simulated wi th planar and axisymmetric configurations, as well as external and mix ed-compression configurations. The lower-upper Symmetric Gauss-Seidel scheme combined with a symmetric shock-capturing total variation dimin ishing scheme are used to solve the Euler equations, with nonequilibri um chemical reactions. The finite rate chemistry model includes 13 spe cies (H-2, O-2, H, O, OH, H2O, HO2, H2O2, N, NO, HNO, N-2) and NO2) an d 33 reactions. The numerical method has been verified by comparison w ith H-2/air induction delay times, analytical solutions to wedge probl ems, and exothermic blunt body flows. Results obtained with an invisci d, chemically nonequilibrium numerical approach and with realistic geo metries demonstrate that shock-induced combustion can be used as a via ble means of hypersonic propulsion. As part of the combustor design, i t has also been numerically demonstrated that a minimum-entropy, or Ch apman-Jouguet condition exists for oblique-detonation waves generated by wedges in nonequilibrium chemically reacting H-2/air flowfields.