Evaluation of radiative properties of a representative foam structure using blocked-off region approach integrated with finite volume method

A Finite Volume Method (FVM) based numerical model is developed to determine radiative properties of unit cell porous structure that represents a ceramic/metallic foam. Blocked-off region approach is used to model an idealized unit cell structure. Effective reflectance and transmittance of a unit cell are obtained numerically using FVM. Recurrence relationship is then used to determine effective reflectance and effective transmittance between layers of porous cells. Based on these values of reflectance and transmittance, the radiative properties, i.e. the extinction coefficient and the scattering albedo are calculated for an equivalent homogeneous porous media. Genetic algorithm is used to predict these properties using an inverse analysis. Developed model is validated using the previously published results and its accuracy is found satisfactory. Effect of solid reflectivity, porosity and pore density on radiative properties of open cell porous structure are also studied. It is observed that extinction coefficient increases with increase in solid reflectivity and decrease in porosity. Similarly, scattering albedo also increases with increase in solid reflectivity. No significant variation of scattering albedo is observed with porosity.