A development to determine spectral radiative properties of semitransparent struts of open-cell ceramic foams: From macro-scale measurement to pore-scale simulation

The radiative properties of a ceramic strut cannot be strictly the same as that of a dense sintered ceramic bulk composed of the same material. This contribution develops an approach to determine the radiative properties of semitransparent ceramic struts of open-cell foams. First, a macro-scale measurement was conducted to obtain the normal-hemispherical transmittance and reflectance spectra of alumina foam slices. Second, a pore-scale forward model was established to predict the radiative behaviors of 3D digital porous structures obtained from micro-computed tomography technique. Last, an identification method was proposed to retrieve the radiative properties of semitransparent ceramic struts from the measured data. The results indicate that it is unreasonable to simply assume the radiative properties of alumina struts as that of corresponding dense bulks. Within the investigated wavebands 0.4–2.2 μm, the average extinction coefficient of alumina struts is 33.5% lower than that of dense bulks. The scattering albedo shows a slight difference between alumina struts and dense bulks. Besides, the retrieved extinction coefficients and scattering albedos of alumina struts are proposed as a function of wavelengths, which can be used in potential applications.