An improved correlation law of the extinction coefficient for open-cell strut-based foams in view of volumetric solar absorber design

We propose an extended law for the extinction coefficient of architected structures composed of interconnected cylindrical struts. The relationship, expressed as β = − ln 1 − θ 0 . 46 / L s , is evaluated against Monte Carlo ray-tracing simulations performed on digitally generated porous networks, enabling a direct numerical measurement of extinction. Comparisons with existing correlations demonstrate that the proposed formulation successfully extends their applicability to the very high porosity range (70% to 98%), providing an effective homogenized description of radiative properties relevant for the modeling and design of volumetric solar absorbers. • A new analytical extinction law derived from probabilistic arguments. • The proposed law captures asymptotic behavior and valid over wide porosity range. • A 3D stochastic geometry and Monte Carlo ray-tracing developed. • Agreement with Monte Carlo results, < 3% mean error observed. • Provides basis for homogenized solar absorber modeling.