Decoupling the Roles of Conductivity, Architecture, and Pore Diameter in Transpiration Cooling Through Sintered Metallic Porous Media

Abstract Transpiration cooling through sintered metallic porous media is a promising active thermal-protection strategy for high-heat-flux aerospace and propulsion applications, yet the relative influence of the solid material, the pore architecture, and the pore diameter on cooling performance has not been established within a single, internally consistent framework. This study presents a combined experimental and numerical investigation that decouples and ranks these three parameters. The results establish a clear sensitivity hierarchy in which solid thermal conductivity exerts the dominant influence, pore architecture a secondary influence, and pore diameter a comparatively minor influence: the titanium specimen attained cooling effectiveness values of 0.77–0.88 against 0.567–0.677 for the SS316L wire mesh, the isotropic sintered powder outperformed the anisotropic wire mesh, and the difference between the 80 μm and 100 μm meshes was limited to approximately 2.3%. The model reproduced the measured cooling effectiveness with a root-mean-square error of 0.090 while recovering physically consistent injection velocities and revealed that the classical Kozeny–Carman relation over-predicts the permeability of consolidated woven meshes by up to two orders of magnitude—identifying the effective permeability as the principal source of residual model uncertainty. The combined findings yield validated design guidance for transpiration-cooled components, prioritizing high-conductivity matrices and isotropic pore architectures, and identify direct permeametry as the key measurement required to render the flow closure fully predictive.