Prediction of radiative heat transfer in a 2D enclosure with blocked-off, multi-block, and embedded boundary treatments

A prediction of radiative heat transfer in a complex geometry was performed using different boundary treatments such as blocked-off, spatial-multiblock, and embedded boundary methods. The formulation of embedded boundary treatment for finite volume was derived here. The finite-volume method (FVM) was used to model the radiative transfer in an absorbing and emitting medium which is maintained at an isothermal condition and enclosed by cold and black walls. While the body-fitted grid system was used for the spatial multi-block treatment, the Cartesian grid system was chosen for the others. Their results were compared and discussed for three different cases including trapezoidal enclosure, semi-circular enclosure with internal block, and incinerator-shaped enclosure. The accuracy obtained by application of each treatment was shown to be highly satisfactory. Consequently, each treatment was suitable for modeling the radiative heat transfer in the complex geometry. However, the solution obtained by the blocked-off treatment has yielded some errors compared with the others, since the Cartesian grid used in the blocked-off treatment could not exactly configure the complex boundaries. Especially, the radiative heat flux on the non-orthogonal wall was largely underestimated due to its stepwise description of the wall.