Abstract
A combustion/radiation model is developed to predict the radiation from laminar hydrocarbon/air diffusion flames. The combustion is treated as in the classical thin flame, with the Shvab-Zeldovich parameter leading to an estimate of the temperature and concentration of radiating gases. A steady-state assumption is applied to the global kinetic mechanism leading to the soot concentration, which in turn is related to the local Shvab-Zeldovich parameter through the temperature and mass fractions of fuel and products, Yf and Yp. For the specific case of PMMA burning in a laminar opposed-flow of air, the spectral soot absorption coefficient at 633 nm has been correlated with
where aλ has units of m−1, the pressure P is in atmospheres, and the temperature is in Kelvin. The radiation from the flame can be found by using the Total Transmittance Nonhomogeneous Model (TTNH) once the temperature, concentration, and soot absorption are calculated from the Shvab-Zeldovich parameter.