Analysis of Ultraviolet Radiation Predictions from High Altitude Two-Phase Plumes

Numerical study of a 5900-Ib solid propellant thruster plume at an altitude of 118 km is performed using a combined multistep continuum/kinetic approach. The Navier-Stokes equations are solved for the flow inside the nozzle and the first several meters into the plume. The direct simulation Monte Carlo method is used to simulate the remaining plume and the plume-free stream interaction. A Monte Carlo based radiation code is applied in an overlay mode to calculate ultraviolet radiation in the near and far field of the plume. The computations take into account both alumina particles and soot. The effect of alumina particle emissivities and size distribution, as well as soot concentration, on ultraviolet radiation is clarified. Comparison of numerical results with available ultraviolet measurements is conducted.