Accurate molecular and soot infrared radiation model for high-temperature flows

The accurate computation of infrared spectral radiation from high-temperature, nonequilibrium flows remains a challenging problem, particularly for polyatomic species and particulates. A versatile computer model for calculating the infrared radiation of water and carbon dioxide and soot in generic flowfields is proposed and examined. Molecular radiation is calculated using the high-resolution transmission absorption molecular database/ high-temperature spectroscopic absorption parameters and carbon dioxide spectroscopic databank-1000 line-by-line databases to provide high-resolution, accurate spectra between 200 and 8200 cm^-1. Soot particulate radiation is modeled using the first-term approximation of Mie scattering theory, and the pseudogas approximation is used. The program was parallelized in spectral increments to run efficiently on a message-passing interface equipped cluster. Validation was performed against well-documented radiation models such as ATHENA and nonequilibrium air radiation - infrared. Soot radiative properties were validated against measurements made on a sooting diffuse laminar flame, and carbon dioxide spectra were validated against experimental data. The computer radiation model is applied to two situations: a nonequilibrium bow shock and an Atlas-like sooting plume.