DETERMINATION OF ANISOTROPIC ABSORPTION AND EXTINCTION COEFFICIENTS OF A TOMOGRAPHED REAL POROUS MEDIUM

摘要

The direct general identification method of the radiative properties of high porosity media, developed and validated for virtual statistically isotropic media in [1], has been applied to a real statistically anisotropic medium. This medium has a transparent fluid phase and an opaque gray diffuse solid phase. It is modelled by a semi-transparent equivalent medium characterized by extinction and absorption coefficients β and κ. These quantities are directly determined from the morphology data obtained by X-ray tomography and from the absorptivity of the solid phase. The application of this approach to a mullite sample has established that β and κ are homogeneous but depend on direction. This last feature has to be accounted for by a radiative transfer method for this type of medium.