Thin Film Heat Flux Sensor With Sandwich Structure for Extreme Temperature Environment

The ability to monitor the accurate heat flux distribution on turbine blade could allow better running status and fault diagnosis for aero engines. However, the heat flux sensors currently can not endure the extreme high temperature with low sensitivity. A novel thin film heat flux sensor (TFHFS) with the sandwich structure was designed and fabricated in this work. The sensor was calibrated with heat flux up to 110 kW/ $\text{m}^{{2}}$ . The sensor contained 19 pairs of Pt/Pt-13Rh thermocouples sandwiched between two thermal resistance layers. The sandwich structure can improve the temperature gradients between hot and cold junctions, and the sensitivity of the sensor is $1.15\times 10^{-{5}}$ V/(kW/ $\text{m}^{{2}}$ ). The sensor survived after a prolonged thermal cycling for 3 h at 1000 °C. It turns out that the TFHFS with sandwich structure shows high sensitivity and can operate up to 1000 °C, proving that the sensor can measure heat flux at high temperature.