Non-Contact Temperature Sensor for Engine Hot Section Components

ABSTRACT: A non-intrusive sensor system for surface temperatures in harsh environments will be adapted to enable measurements on turbine blades during engine operation. The approach involves applying a layer of thermographic phosphor on top of the thermal barrier coating (TBC) of the engine component, resulting in a sensor coating that is fully compatible with the TBC and durable enough to survive the high temperature combustion gases. A spot on the engine component is illuminated by a laser pulse, causing the sensor layer to luminesce with spectral and temporal characteristics that depend on temperature. Light from the measurement spot is collected with a probe, and the luminescence signal is transmitted through a fiber optic to a remotely located detector. Signals from the detector are analyzed to provide temperature from the luminescence decay rate. There is no physical contact with the object being measured, thus rotating as well as stationary parts can be measured. Since the method does not rely on measurements of absolute intensity, it is not particularly sensitive to window fouling, and the effects of background radiation can be mitigated by using short wavelength phosphors and time gating. BENEFIT: The sensor system will provide engine designers and researchers with a valuable tool for measuring turbine blade temperatures that will aid in the development of advanced turbine engines. Since engine performance is directly linked to the maximum temperature of the combustion gases, the operating temperature of turbine hot section components is a critical parameter. By enabling temperature measurements of critical components with greater accuracy, engine designers will be able to reduce the permissible margin between estimated temperature and the absolute material limit, thereby enabling higher operating efficiencies, which should lead to greater thrust, lower fuel consumption, and lower emissions.