Oxygen quenching of phosphorescence from thermographic phosphors

Abstract

Thermographic phosphor thermometry is a technique for surface temperaturemeasurement which may be employed in the hot sections of a gas turbineallowing temperature detection up to around 1400 °Cwith uncertainties better than for other remote standard techniques such aspyrometry. The phosphors have been regarded as pressure insensitive and indeedhave been used to provide reference temperature data for the correction ofpressure-sensitive paint data. The authors wish to employ the technique in gasturbine combustors where oxygen partial pressure varies widely due to itsconsumption in the combustion reaction. An experiment was therefore conductedto confirm the pressure/oxygen insensitivity of two high-temperaturephosphors. However, this revealed a response to oxygen partial pressure thatimplies an uncertainty in temperature measurements within the primaryzone of a combustor of typically 1%. There does not appear to have beenany previous report of such a response in the literature and this notetherefore serves as a caution to those employing the thermographic phosphorthermometry technique where oxygen partial pressure varies significantly.