Аннотация:Two skeletal kinetics mechanisms for reactive CH 4/O2 and H2/O2 ram accelerator e owe elds are presented. Both models were derived from a 190-reaction, 38-species kinetics mechanism (RAMEC or RAM accelerator MEChanism) that successfully reproduces the high-pressure (>50 atm), low-dilution (<70%), fuel-rich chemistry of ram accelerator mixtures. The reduction procedure for the CH 4/O2 mechanism utilized a detailed-reduction technique with ignition delay time and heat release as the selection criteria. The methane-based mechanism (REDRAM or REDuced RAM accelerator mechanism ) contains 34 reactions and 22 species and predicts ignition times to better than 5% and postcombustion temperatures to within 10 K of the full mechanism for a representative range of ram accelerator mixtures and conditions. This CH 4/O2 mechanism is an improvement over existing reduced methane-oxidation mechanisms that arebased on lower-pressure, higher-temperature chemistry. An 18-step, 9-species mechanism is presented for hydrogen-based ram accelerator combustion that is based on the H2/O2 submechanism of the RAMEC/Gas Research Institute GRI-Mech 1.2 methane-oxidation mechanism. The H2/O2 kinetics model includes HO 2 and H2O2 chemistry near the second and third explosion limits, necessary for ignition at ram accelerator pressures but lacking in certain e nite rate chemistry models currently in use.
