Pressure drop and convective heat transfer in porous ceramic structures fabricated by additive manufacturing

The microstructure of porous materials has a significant effect on their transport properties. Engineered cellular ceramics can be designed to exhibit properties at will, thanks to the advances in additive manufacturing. We investigated the heat and mass transport characteristics of SiSiC lattices produced by 3D printing and replication, with three different morphologies: rotated cube, Weaire-Phelan and tetrakaidecahedron lattices, and a commercially available ceramic foam. The pressure gradients were measured experimentally for various velocities. The convective heat transfer coefficients were determined through a steady state experimental technique in combination with numerical analysis. The numerical model was a volume-averaged model based on local thermal non-equilibrium assumption of the two homogeneous phases. The results showed that for tetrakaidecahedron and Weaire-Phelan structures, undesirable manufacturing anomalies (specifically window clogging) led to unexpectedly higher pressure drops across the samples and increased thermal dispersion. Compared to the tetrakaidecahedron and Weaire-Phelan structures, the manufactured rotated cube lattice and the random foam had lower heat transfer rates but also lower pressure drops. These lower values for the rotated cube lattice and foam are also a result of their lower specific surface areas.