A COMPARISON OF RADIATIVE CHARACTERISTICS FOR FLY-ASH AND COAL

Numerical results for extinction efficiency, phase function, albedo and asymmetry factor are presented for clouds of spherical particles illuminated by black body radiation. The refractive indices (m equals m//1 minus im//2) used were m//1 equals 1. 5 with m//2 varied from 0 to 0. 024 in steps of 0. 006 and m equals 1. 6 minus i0. 6, chosen to be representative of fly ash and coal. Averaged scattering data are given for use in radiative transfer modeling of pulverized fuel furnaces. The results are seen to depend on the product of the mean particle size and the radiation temperature. The scattering parameters of fly ash are shown to vary significantly with absorption index m//2 for small particles but the choice of refractive index is not critical for large particles.