Research progress of fiber optic sensing technology in total temperature measurement of high-speed airflow

The total temperature of high-speed airflow is a critical physical parameter in aerothermodynamics and serves as a key indicator for evaluating the performance and efficiency of aero-engines. Conducting high-speed, high-precision measurements of the airflow total temperature is essential to ensuring the safe and efficient operation of aero-engines. Currently, traditional electrical methods for total temperature measurement, typically represented by thermocouples, face technical bottlenecks in further improving measurement accuracy and response time. Fiber-optic sensing technology, characterized by its micro-scale structure, strong interference immunity, high-temperature tolerance, and high sensitivity, demonstrates significant potential for practical applications in the field of high-speed airflow total temperature measurement. Based on the requirements for high-speed airflow total temperature testing, this paper systematically elaborates on the working principles of threetypical fiber optic sensing technologies—fiber Bragg grating (FBG), fiber Fabry-Pérot (FFP) interferometry, and blackbody radiation—in the field of total temperature measurement. It introduces representative application cases of these technologies in high-speed airflow total temperature testing and provides a comparative analysis of their advantages, limitations, and applicability. The paper reviews the latest theoretical and experimental advances aimed at improving the accuracy and response time of fiber-optic total temperature testing. In particular, the research conducted by Chongqing University in fiber-optic total temperature testing for subsonic flows is presented in greater detail, as this work is relatively systematic and comprehensive. Finally, to address the technical challenges in fiber-optic total temperature testing, the paper outlines prospects for the development and application of fiber-optic sensing technology in high-speed airflow total temperature measurement.