Three-Dimensional Spectral Radiative Heat Transfer Solutions by the Discrete-Ordinates Method

Radiative heat transfer in three-dimensional enclosures with a participating medium is predicted using the discrete-ordinates method formulated for spectral variations in the radiative properties. The spectral distribution of radiation is subdivided into a finite number of bands within which the properties are assumed uniform. The method uses a control volume formulation of the discrete-ordinates equations for each band. Solutions are found for each hand, and are summed to obtain the total contribution. The solution strategy and stability are discussed in the paper. Results have been obtained for the S-4 method, a 24-flux approximation. Solutions are benchmarked with several methods. Examples are presented for enclosures with spectral walls and with absorbing mixtures, and absorbing and scattering media, to show the importance of mixture albedo and refractive index on net wall heat flux. The favorable results indicate that the spectral discrete-ordinates method offers an alternative that is easily adaptable and usable in existing control volume transport codes.