Acquisition and reconstruction of scattering characteristics of thermal insulation ceramics

Accurately obtaining the radiation properties of insulating ceramic materials is essential for engineering applications. This article obtained the bidirectional transmittance and reflectance of thermal insulation ceramics, and introduced a new scattering phase function to establish a radiation transfer model based on Monte Carlo method. Combined with parallel genetic algorithm inversion, radiation properties such as extinction coefficient, scattering albedo, and scattering phase function are obtained. Firstly, the experimental optical path is simulated and analyzed, which has little effect on the measurement results due to slight deflection of strong extinction material samples and detectors. For the measurement of bidirectional transmittance, a larger spot radius and detector radius will increase the measurement bidirectional transmittance. Secondly, through parallel genetic algorithm inversion, >5 measurement points are required to obtain their radiative properties, however, the radiation properties of backscattering materials cannot be precisely obtained using bidirectional transmittance for inversion. The required inversion accuracy can be achieved when the bidirectional transmittance and reflectance ratio measurement angle step is <4 °. Finally, this study determined the radiation properties of ceramic insulating materials that show little wavelength variation, their spectral extinction coefficients are above 9000m⁻¹, and spectral scattering albedo are greater than 0.9. It is difficult to characterize scattering features using isotropic scattering phase functions because materials have both forward and backward scattering characteristics. The scattering characteristics of insulation ceramics described using the newly proposed scattering phase function have higher accuracy.