Experimental and Simplified Predictive Determination of Extinction Coefficients of Ceramic Open‐Cell Foams Used for Metal Melt Filtration

Abstract

A main application area of ceramic open‐cell foams is the foundry, where the porous media are used for conditioning and filtration of the melt flow. As characterization of heat transfer in such high‐temperature applications requires consideration of thermal radiation, knowledge of the radiative properties of the foams is essential. Instead of elaborative measurements or simulations, empirical correlations often serve as a simple and fast method to predict extinction coefficients. However, significant differences up to 100 m−1 occur between calculated values of various models presented in the literature. Herein, it is aimed to characterize the radiation behavior of different ceramic foams experimentally and identify reliable, simple yet accurate methods for the prediction of extinction coefficients of these materials by comparison with experimental results. The influences of pore density (10 and 20 pores per inch [ppi]) and filter material (Al2O3, ZrO2, SiC, Al2O3−C) on the transmittance, reflectance, and extinction coefficients are investigated by spectroscopic measurements. Two models from the literature are determined, which are well suited to predict extinction coefficients with an average deviation of less than 20%. Furthermore, accurate estimation with an average deviation of 12% can be also achieved using a projection method based on computed tomography scans of the foams.

Thermophysical properties of polymer composite materials based on TO-29-2 epoxy binder alloyed with AIN

“…The thermal conductivity (λ) was carried out by the transient plane source method on a Hot Disk TPS 2500S installation [6,7] in the temperature range from 78 to E3S Web of Conferences 459, 10003 (2023) https://doi.org/10.1051/e3sconf/202345910003 XXXIX Siberian Thermophysical Seminar 300 K. Two plane-parallel cylindrical samples with carefully polished ends for each PCM with a diameter of 20 mm and a thickness of 15 mm were fabricated for λ measurements. Transiently heated plane sensor (30 µm thick) of the Hot Disk setup was clamped in the center between two disks of the investigated material.…”

Selective Nitridation of Ceramic Open Cell Foams for Efficient Photothermal Heating

“…Additionally, as also reported in our previous work, [ 26 ] porous ceramics can be engineered to enhance the effective extinction coefficient by internal light scattering at the high‐refractive‐index surfaces of the ceramic structure leading to efficient light propagation onto the plasmonic particles. [ 32 ]…”

“…Additionally, as also reported in our previous work, [26] porous ceramics can be engineered to enhance the effective extinction coefficient by internal light scattering at the high-refractive-index surfaces of the ceramic structure leading to efficient light propagation onto the plasmonic particles. [32] To this end, we present a novel strategy to fabricate a fully ceramic plasmonic porous material based on the plasmonic transition metal nitride TiN and an inert alumina ceramic matrix and demonstrate its potential for plasmonic heating applications. Preparation of the mixed oxide/nitride ceramics is based on the molten salt synthesis route and the ceramic open-cell foam structure is processed via the polymer replica method.…”