| Summary: | <p>This paper presents a novel experimental technique where infra-red thermography is employed to directly measure the surface heat transfer of a transpiration cooled porous material in transient hypersonic flow. Experiments were conducted in the Oxford High Density Tunnel on a flat faced hemispherical probe at a single Mach 7 free-stream condition (𝑅𝑒𝑢 = 3.84·106 1/m) with Nitrogen, Air, Argon, Krypton and Helium injection gases and mass flow rates ranging from 0.01-0.235 kg s−1m−2 . Surface heat transfer measurements were extracted by imaging directly on the porous material using a FLIR A6751 high-speed long-wave infra-red camera. Porous alumina was chosen due to its favourable thermal properties for infra-red analysis and its very small pore sizes (≈ 2 𝜇m) enabling a uniform outflow. It was found that the Stanton number reduction matched to within 10% of both CFD results and correlations.</p>
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