Tuning the spectral emittance of α-SiC open-cell foams up to 1300 K with their macro porosity

Abstract

A simple and robust analytical model is used to finely predict the spectral emittance under air up to 1300 K of α-SiC open-cell foams constituted of optically thick struts. The model integrates both the chemical composition and the macro-porosity and is valid only if foams have volumes higher than their Representative Elementary Volumes required for determining their emittance. Infrared emission spectroscopy carried out on a doped silicon carbide single crystal associated to homemade numerical tools based on 3D meshed images (Monte Carlo Ray Tracing code, foam generator) make possible to understand the exact role of the cell network in emittance. Finally, one can tune the spectral emittance of α-SiC foams up to 1300 K by simply changing their porosity.

Ultralight and High-Strength SiCnw@SiC Foam with Highly Efficient Microwave Absorption and Heat Insulation Properties

“…In 2016, Rousseau et al proposed a numerical analysis model for predicting the spectral emissivity of porous SiC-based foams in high-temperature environments . Studies have shown that the smaller the internal pores of the SiC-based foam, the higher the porosity, which leads to a more tortuous skeleton structure and better thermal insulation performance.…”

“…In 2016, Rousseau et al proposed a numerical analysis model for predicting the spectral emissivity of porous SiCbased foams in high-temperature environments. 51 Studies have shown that the smaller the internal pores of the SiC-based foam, the higher the porosity, which leads to a more tortuous skeleton structure and better thermal insulation performance. In order to explain the excellent thermal insulation performance of the SiC nw @SiC foam more intuitively, the schematic diagram of the heat transfer mechanism is shown in Figure 8b.…”

COMBINING MICRO- MESO- AND MACRO-SCOPIC NUMERICAL METHODS FOR MULTISCALE RADIATIVE TRANSFER MODELING OF SiC-BASED FOAMS UP TO VERY HIGH TEMPERATURES

“…The resulting mode, known as for Longitudinal Optical phonon Plasmon Coupled, will be treated in the next part as a phonon-like type particle. Thirdly, the simulations will be IHTC16-24216 3 carried out only at = 300 K since higher temperatures do not modify ̃, , as it can be shown for = 10 19 cm -3 by infrared emittance spectroscopy [17]. Once these basis are settled, the MD technique consists in applying the Newton's second law for computing all positions, , and velocities, ̇, for each atoms as a function of the time .…”

“…1b. The thin and thick green curves give the spectral dependence at = 300 K of the complex refractive index of a doped SiC single crystal used to compute the radiative properties of opencell foams with growing porosities and nominal pore diameters [17]. The evolutions of the index of refraction , and absorption , match here completely those obtained by our molecular dynamic approach, knowing that for the two samples are rather identical: around 10 19 cm -3 in [17] and 1.2 10 19 cm -3 in this work (red curves).…”