High-Speed Thermal Imaging of In-Service TBC Blades

Ceramic thermal barrier coating (TBC) on first-stage turbine blades is a vital component of advanced engines under development for future military aircraft, protecting the metal alloy blades from the extreme combustion temperature in these high-performance engines. TBC must be proven as a reliable means to prevent blade failure but current engine development programs are hindered since there is not a sensor available to map the surface temperature of TBC blades during engine operation. In fact, the engine sensor community has identified surface temperature mapping of TBC blades as a high priority sensor development need. This Phase I project will demonstrate feasibility for an advanced optical imaging system for both on-board TBC emissivity mapping and TBC temperature mapping. Knowledge of TBC emissivity is critical for accurate temperature measurements, and jet fuel combustion influences emissivity at the coating surface. The TBC emissivity maps will be used with the TBC thermal maps to improve the absolute accuracy of on-engine TBC temperature mapping. On-board emissivity monitoring will also provide an additional diagnostic for high-resolution monitoring of TBC breakdown resulting in metal substrate exposure.