Monte Carlo Simulation of Particle Radiation in High Altitude Solid Rocket Plumes (Invited)

Several recently developed numerical schemes are used in an integrated framework to simulate the plume flow from a representative solid propellant rocket at an altitude of 114 km. In nonequilibrium regions the gas is modeled using the direct simulation Monte Carlo method, while a particle simulation method based on a simplified approximation of the Boltmann equation is used in near-equilibrium regions. Condensed phase Al2O3 particles, which are ejected with exhaust gases through the nozzle, are included in the simulation through a Lagrangian tracking scheme which allows for two-way interphase coupling of momentum and energy. Plume radiation properties are determined through a Monte Carlo ray trace model that incorporates effects of spectrally resolved emission, absorption and scattering. Radiation calculations are strongly coupled to the flowfield simulation, and allow particle emission and absorption to affect properties of both the particles and gas. Simulation results are compared with available experimental measurements, and generally good agreement is found.