Synergetic Optimization and In Situ Fabrication of Thin-Film Heat Flux Sensor for Heat Flux Measurement of Combustion Wind Tunnel

Instantaneous heat flux monitoring of high-temperature components in extreme environments is gaining significant attention for aircraft engines. Recently, advancements in microfabrication techniques have enabled the development of thin-film heat flux sensors (TFHFSs). However, fabricating TFHFS on complex aeroengine components, especially in narrow spaces, remains a significant challenge. In this work, the influence of geometric parameters on the sensor’s physical properties is systematically investigated using numerical simulation methods. Then, a high-temperature Pt/PtRh thermopile TFHFS is fabricated on the Ni-based turbine blade. Experimental results indicate that the proposed TFHFS exhibits a high sensitivity of 19.38 $\mu $ V/(kW/m2) and a response time of approximately 21 ms. Notably, the TFHFS has a nearly constant response in three-cycle tests and exhibits excellent repeatability and stability. Furthermore, the high-temperature combustion wind tunnel test confirms that the TFHFS can operate up to $1000~^{\circ }$ C and withstand a gas flow velocity of 0.9 Mach, indicating that the fabricated TFHFS is suitable for extremely hostile and complex environment measurement applications. This study provides a viable approach for developing various thin-film sensors on complex surfaces and promotes in situ sensing toward practical applications.