Methods for the Material Spectral Emissivity Evaluation by Dual-Color Pyrometer in a Hypersonic Plasma Test Facility

In aerospace applications, the investigation of the physical properties of the materials used as thermal protection systems (TPSs) is mandatory. One of the most important material properties involved in the prediction and measurement of the aerothermal loads is the material surface emissivity. In fact, to set properly optical devices operating in the infrared region of light, it is necessary to know the material emissivity for the measurement of the temperature at surface. In order to perform such analysis during the development of a test in a hypersonic plasma ground simulator, like the CIRA-PWT SCIROCCO and GHIBLI facilities, the INPP Laboratory developed techniques for the investigation of the spectral emissivity by properly using dual-color pyrometers. Those techniques have been applied during tests carried out in the SCIROCCO and GHIBLI facilities on materials candidate for TPS of re-entry space vehicles. In the present work, those techniques are shown and the kind of results obtained during experiments.