A New High-Temperature Sensing Device by Making Use of TBC Thermistor for Intelligent Propulsion Systems

Thermal barrier coating (TBC) is an important material for aero-engine as a good thermal and electrical insulator. However this ceramic layer becomes electrically conductive at elevated temperatures above 600°C. By making use of its thermal resistance sensitivity to ambient temperature a smart thermal sensor can also be formulated to monitor the surface temperature on aero-engine turbine blade. In this paper the fabrication of this new sensor is reported together with comprehensive high-temperature characterizations such as repeatability, responsiveness and measurement error evaluation under various high temperature cycling and aero-engine onsite combustion test. Results show this sensor is capable to test the surface temperature in 500–1 000°C range or higher. YSZ-based (yttria-stabilized zirconia) TBC thermistor sensor shows a reliable and repeatable resistor vs temperature behavior and comparable responsiveness as conventional thermalcouple device with the measurement errors in 3%. Sensor fabrication is fairly simpels just involving a platinum soldering on TBC surface for wiring connection to outside meters. A new test array based on the YSZ thermal resistor is proposed as a temperature distribution monitor and verified by the aid of thermal-electrical interactive simulations. This simple methodology can be used for quick checking of surface temperature on turbine guide vane used in combustion chamber and other relevant parts.