Effect of anisotropic scattering on radiative heat transfer in two-dimensional rectangular enclosures

Comparison of Different Spatial/Angular Agglomeration Multigrid Schemes for Radiative Heat Transfer Computations

“…Two simulations were encountered for the evaluation of solver's accuracy, in which different values of wall emissivity εw were assumed, namely 1.0 and 0.1. In Figure 6 the extracted distributions of dimensionless incident radiative heat flux along the A-A line are illustrated, compared to the corresponding ones reported by Kim and Lee [19]. It is obvious that a very good agreement has been achieved.…”

“…For the evaluation of the efficiency improvement, contributed by the different combinations of the proposed multigrid schemes (i.e., by employing the uniform, alternate, or nested scheme, different V-cycle types, and the combined FMG-FAS method), a benchmark test case was encountered, considering radiative heat transfer in a cubic enclosure with edge length equal to unity [7,10,19]. A schematic representation of the cubic geometry is depicted in Figure 5.…”

“…The included cold medium is assumed purely scattering (σs=1m -1 , kα=0m -1 , Tm=0K). The wall surfaces are considered similarly cold (Tw=0K), except for the bottom face at which a constant heating energy is implemented (E=1W/m 2 ), while for the bases normal to the ydirection mirroring boundary conditions are imposed [7,10,19]. The computational domain is represented by a hybrid grid, composed of 22,500 nodes, 65,480 tetrahedra and 19,460 prisms; for angular discretization the directional domain is divided in 16 azimuthal and 8 polar angles.…”

“…Prior of validating the efficiency improvement, the accuracy of the proposed solver was assessed. The medium is assumed to exhibit anisotropic scattering behavior, which is modelled with the F2 scattering phase function, based on the Legendre polynomials [18,19]. Two simulations were encountered for the evaluation of solver's accuracy, in which different values of wall emissivity εw were assumed, namely 1.0 and 0.1.…”

“…It begins from the coarsest resolution (preliminary stage) while, as the number of iterations is increased, the finer FAS levels are added up to the initial finest one (main stage) [1,4,15]. The proposed numerical schemes are evaluated against a benchmark test case, considering radiative heat transfer through a strongly scattering medium in a cubic enclosure with highly reflecting surfaces [19]. According to the produced results the nested spatial/angular scheme along with the V(2,0)-cycle type appears to be the preferred choice for such simulations.…”