THERMAL RADIATIVE PROPERTIES AND TEMPERATURE-MEASUREMENT FROM TURBINECOATINGS

Recent studies have displayed the spectral radiative properties of cer amic thermal barrier coatings which are finding applications in high p erformance turbine engines. As a function of temperature, a region in the long wavelength infrared spectrum exhibits properties which will m inimize the classical errors associated with temperature measurement b y radiometric detection. Hollow sapphire waveguides transmit the porti on of the long wavelength infrared spectrum which is optimum for radio metric temperature measurement from these materials, while the physica l properties of the sapphire can withstand the combustion conditions w ithin the engine. A prototype long wavelength infrared radiation therm ometer was constructed to obtain surface temperature measurements from coated turbine blades subjected to high temperature combustion condit ions.