Chemistry computations for irradiated hot air

A description is given of a computational model of chemical kinetics in air at temperatures between 300 and 4000$sup 0$K, with and without imposed fluxes of ionizing radiation and uv radiation, at pressures up to 10 atmospheres. Included are 1360 chemical reactions, involving 71 H, C, N, and O-containing chemical species. The reaction set is complete in the sense of including a reverse reaction for every reaction and including the dominant destruction reactions for each species produced. Photochemical reaction rates are computed in terms of a prescribed intensity and spectral distribution of radiant flux. Reactions of the metastable species O($sup 1$D), N($sup 2$D), O$sub 2$($sup 1$$delta$g), and O$sub 2$($sup 1$$Sigma$$sup +$/sub g/) are included explicitly, but all other quantum state populations are assumed to be in thermodynamic equilibrium. Results of several sets of model computations are described. These include: computations of rates of equilibration of systems subjected to abrupt temperature changes at a pressure of 1 atmosphere; computations of relaxation of systems subjected to impulsive sources of ionizing radiation at P = 1 atmosphere and 0.01 atm, with and without superimposed sources of optical-uv radiation; and computations of the approach to steady state in systems subjected to steady sources of ionizing radiation, for pressures between 10$sup -3$ atm and 10 atm. For computing concentrations of electrons, ions, NO, NO$sub 2$, O, N, and O$sub 3$, an abbreviated lumped-parameter reaction set was constructed with 31 reactions, designed to be incorporated in a fluid-dynamics code. Rate coefficients were calibrated against results from the 1360-reaction code for temperatures between 300 and 4000$sup 0$K and pressures between 10$sup -3$ and 10 atm. (auth