Independent and dependent scattering in packed-sphere systems

Abstract

The present work predicts radiative extinction characteristics of packed-sphere systems; both independent and dependent scattering are considered. This pertains to many radiation and heat transfer applications including packed and fluidized beds, microsphere insulations, and soot or paint layers. Mie scattering theory is used to calculate the independent scattering and absorption coefficients of a packed-sphere system. Radiative transfer predictions based on these coefficients and a simple two-flux model provide much better agreement with reliable experimental data than published ray-tracing and Monte Carlo models. The dependent scattering efficiency is calculated via the form factor technique of X-ray scattering theory, which uses a pair distribution function to correlate the relative positions of the constituent particles in the system. Predictions using two-pair distribution functions, a modified-liquid model, and the hard-sphere Percus-Yevick model show excellent agreement with published experimental data. a a