ROCKET PLUME RADIATION BASE HEATING BY REVERSE MONTE-CARLO SIMULATION

A reverse Monte Carlo radiative transfer code is developed to predict rocket plume base heating. It is more computationally efficient than the forward Monte Carlo method, because only the radiation that strikes the receiving point is considered. The method easily handles both gas and particle emission and particle scattering. Band models are used for the molecular emission spectra, and the Henyey-Greenstein phase function is used for the scattering. Reverse Monte Carlo predictions are presented for 1) a gas-only model of the Space Shuttle main engine plume; 2) a pure scattering plume with the radiation emitted by a hot disk at the nozzle exit; 3) a nonuniform temperature, scattering, emitting, and absorbing plume; and 4) a typical solid rocket motor plume. The reverse Monte Carlo method is shown to give good agreement with previous predictions. Typical solid rocket plume results show that 1) CO2 radiation is emitted from near the edge of the plume; 2) H2O gas and Al2O3 particles emit radiation mainly from the center of the plume; and 3) Al2O3 particles emit considerably more radiation than the gases over the 400-17,000-cm-1 spectral interval.