Progress in radiative transfer in porous medium: A review from macro scale to pore scale with experimental test

Porous medium had the advantages of high porosity, large specific surface area and three dimensional micro-nano cross scale transfixion, which had been widely used in the fields of solar energy conversion, aviation, spaceflight, warship, automobile, combustion, catalysis, waste heat recovery and so on. Porous medium can be oriental designed to achieve excellent physical properties and heat transfer enhancement performances. When porous medium was used in the solar conversion systems and high-temperature applications, radiative transfer played a dominant role during the photon transfer and energy conversion process. The current state-of the-art review on the mechanism of radiative transfer in porous medium from macro scale to pore scale, the principle of radiative property measurement at environment temperature as well as high temperature was presented, with emphasis on the latest developments during the last decade. Advantages and disadvantages of solving the radiative transfer in the pore skeleton of porous medium based on both the geometrical optic theory and electromagnetic radiation theory were discussed in detail, in which the effects of polarization, diffraction and independent scatters in the pore skeletons of porous medium were considered or not. The literature review indicated that, in the further research on the radiative transfer in porous medium, the criteria for judging the limits of independent scattering of porous medium needed to be resolved and accurate radiative property measurement system at high temperature coupled with high precision inversion method needed to be developed.