An accurate and computationally fast formulation for radiative fields and heat transfer in general, plane-parallel, non-grey media with antisotropic scattering

A radiative transfer formulation is applicable to non-grey, plane-parallel, inhomogeneous media with anisotropic scattering is presented. The formulation is based upon the use of certain scattering functions to calculate the diffuse intensity fields in the medium. These scattering functions represent the response of the medium for unidirectional point probes (driving illumination). A computationally fast 'adding' scheme is used to calculate the scattering functions. The adding method is based upon the linearity of the radiative transfer equation, which allows superposition of finite medium layers while calculating the scattering functions. General reflecting boundary surfaces are included in this scheme. A parallel invariant imbedding program, which provides exact but computationally expensive results, is used to characterize the accuracy of the adding procedure. This comparison yields a rule of thumb which helps in estimating and controlling errors.