Abstract
Normalization of various phase functions is considered for accurately predicting radiative heat transfer. A solar absorber tube filled with anisotropic scattering working medium is used as an example. Analysis of previous normalization techniques show that while they do conserve scattered energy exactly after DOM discretization, the overall asymmetry factor of the phase function is distorted, leading to substantial changes in overall scattering effect. An innovative normalization technique which conserves asymmetry factor and scattered energy simultaneously is investigated. The impact of lack of asymmetry factor conservation is analyzed for both the Legendre polynomial and HG phase function approximations. Heat flux at the surface and energy absorbing rate inside the solar absorber tube are predicted using the new normalization technique. Variations of medium optical thickness, scattering albedo, asymmetry factor, and side wall emissivity are scrutinized to determine the effect of said parameters on wall heat flux and energy absorbing rate inside the absorber tube. Side wall heat flux is found to increase with increases in asymmetry factor, optical thickness, and wall emissivity, and with decreases in scattering albedo. Energy absorbing rate profiles are found to depend greatly on optical thickness and scattering albedo.