Thermal Radiation Properties in Porous Media

Porous media comprise a solid framework interspersed with voids that significantly alter heat transfer by adding a radiative component to the conventional conduction and convection channels. Within these materials, thermal radiation is governed by absorption, scattering and emission processes that depend sensitively on pore geometry, size distribution and solid-phase optical properties. High porosity tends to reduce conductive resistance but increases the depth of radiative penetration, giving rise to volumetric absorption in semi-transparent matrices. Microstructural parameters such as pore diameter, strut thickness and surface emissivity can be tuned to balance radiative and conductive fluxes, enabling lightweight thermal protection and improved energy-efficient insulation. Quantitative understanding of these phenomena relies on advanced experimental techniques—such as laser flash analysis—and sophisticated numerical models that integrate radiative transfer equations with conduction and convection solvers. Applications span from aerospace thermal shields and passive cryogenic radiators to photocatalyst carriers and high-temperature structural insulators.

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Thermal Radiation Properties in Porous Media publication trend

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Technical terms

Porosity: The fraction of a material’s volume occupied by voids, which influences all modes of heat transfer.

Emissivity: The efficiency with which a surface emits thermal radiation compared to a perfect black body.

Spectral absorptance: The proportion of incident radiation at a specific wavelength absorbed by a material.

Anisotropic scattering: Direction-dependent deflection of radiation within a medium, affecting apparent radiative transport.

Monte Carlo method: A stochastic numerical approach that uses random sampling to solve radiative transfer problems in complex geometries.

References

1. Design of Aerospace Vehicles’ Thermal Protection Based on Heat-Insulating Materials with Optimal Structure. Aerospace (2023).
2. Radiative, conductive and convective heat-transfers in a single Monte Carlo algorithm. Journal of Physics Conference Series (2016).
3. Complexity matters: Highly-accurate numerical models of coupled radiative–conductive heat transfer in a laser flash experiment. International Journal of Thermal Sciences (2021).
4. Simulation of the Light Transmittance in Macroporous Silica. Materials (2020).
5. Prospective of employing high porosity open-cell metal foams in passive cryogenic radiators for space applications. IOP Conference Series Materials Science and Engineering (2017).