Transient Measurement of Temperature Distribution Using Thin Film Thermocouple Array on Turbine Blade Surface

Abstract

Smart sensors are needed to achieve a more intelligent aero-engine. The thin-film sensor array is thereby fabricated on the turbine blade surface using MEMS technology to measure the surface temperature distribution for the first time. A series of PtRh/Pt thin film thermocouple (TFTC) is directly integrated in-situ on blade surface by dry film photolithography and magnetron sputtering technology. A series of high temperature experiments are performed to test its annealing effect, stability and repeatability, responsiveness, and temperature distribution. The experimental results show that after annealing at 800 °C for 1 hour, TFTCs exhibit good stability and consistency. This TFTC array can capture the temperature distribution caused by the heat flame on the blade surface, and the transient temperature responsiveness can reach at least 10 μs under a dynamic heat flow. The TFTC is only 1 μm thick thin film coated on the blade surface and the thin film routing can direct the joint connection to the edge of the blade, hence causing minimum surface heat flow patterns and structure modulation. Therefore such TFTC array is very useful for accurate transient temperature measurements such as on turbine blade surface, comparing to the wired thermocouple method.