Arc-jet testing of ultra-high-temperature-ceramics

The article deals with arc-jet experiments on different ultra high temperature ceramics (UHTC) models in high enthalpy hypersonic non-equilibrium flow. Typical geometries of interest for nose tip or wing leading edges of hypersonic vehicles, as rounded wedge, hemisphere, and cone are considered. Temperature and spectral emissivity measurements have been performed using pyrometers, an IR thermocamera and thermocouples. The details of the experimental set-up, the test procedure and the measurement are discussed in the text. The UHTC materials have been tested for several minutes to temperatures up to 2050 K showing a good oxidation resistance in extreme conditions. Differences between the various model shapes have been analyzed and discussed. Numerical–experimental correlations have been carried out by a computational fluid-dynamic code. The numerical rebuilding also allowed to evaluate the catalytic efficiency and the emissivity of the materials at different temperature.