Benchtop Instrument for Measuring High Temperature Surface Emissivity (CRP)

The testing of the high temperature materials at AEDC requires measurement of surface temperature. Infrared cameras are used for non-contact, spatial measurements, but for accurate temperature the infrared emittance of the material must be known at comparable temperature, view angle, and camera spectral range. The Phase I and II projects demonstrated that many problems of measuring emittance with a benchtop instrument could be overcome with a novel methodology using both spectral radiance and reflection/transmittance measurements. Phase II delivered a unique high temperature spectral emissometer to the Aero-Thermal Material Laboratory at AEDC. The instrument has worked well for many years but is presently limited in capability for present day applications for hypersonic flight systems and vehicles undergoing testing at AEDC. Capability for higher temperatures and multiple angles is presently required. This CRP will incorporate state-of-the-art components and improve automation, measurement speed and user-friendliness. To meet present day applications, the enhanced spectral emissometer will provide measurements at four take-off angles of 1524°, 30°, 45° and 60°, and it will provide for measurements at sample temperatures from room temperature to above 3000°R with 5000°R as the stretch goal. It will meet the infrared wavelength range requirement of 0.8 to 20 microns.