Radiation Properties for Polydispersions: Application to Coal

Abstract

The extinction and absorption coefficients and the asymmetry factor for polydispersions of absorbing spherical particles are analyzed. The results are based upon Mie’s theory for single spherical particles and particle size distributions found in practical systems. Dimensinnless spectral radiation properties are shown to be independent of the explicit size distribution and functions only of the average radii and the index of refraction. The Planck and Rosseland mean coefficients are also presented and the dependence on temperature is explicitly denoted for a large practical temperature range. The results for coal with optical properties which are wavelength dependent indicate the usefulness of the dimensionless and mean properties.

Thermal radiation in oxy-fuel flames

“…For the scattering particles, correlations presented by Buckius and Hwang (1980) are used to calculate scattering albedo and extinction coefficients. The correlations are expressed with a dimensionless extinction and absorption coefficient, defined aš *…”

Spectral Photon Monte Carlo With Energy Splitting Across Phases for Gas–Particle Mixtures

“…In this PMC implementation, we consider previously derived correlations of spectral absorption coefficients for solid particles j g,s , which can be found in [10,29]. With these empirically derived correlations as a starting point, we derive correlations of random numbers versus wavenumbers and other physical properties of particles.…”

“…The particle absorption coefficient correlations of Buckius and Hwang [29] define a normalized absorption coefficient…”

“…For reference, complex indices of refraction of selected solids are provided in Table 1. The Buckius and Hwang correlation equation for particle absorption coefficients is [10,29] …”

Eulerian–Eulerian multi-fluid methods for pulverized coal flames with nongray radiation

“…The complex refractive indices of solid phases are used to calculate bulk spectral radiative properties (absorption, scattering and extinction coefficients) of the solid phase through the BuckiusHwang correlations [29]. It should be noted that due to the dependency of size ratio on wavelength (i.e.…”