Research on an FBG Sensor for High Accuracy Measurement of Fluid Temperature in Inlet and Outlet Pipelines

For the temperature control system of aerospace fluid pipelines, high-precision and high-response miniaturized temperature sensors are required to achieve precise temperature control and rapid measurement while minimizing the impact on fluid velocity. In this regard, the present study investigates a fiber Bragg grating (FBG) sensor for simultaneous monitoring of inlet and outlet pipelines temperatures. Through theoretical calculation and simulation, the sensor structure is designed to ensure its adaptability to the mechanical environment of aerospace fluid pipeline monitoring and sealing performance, and the sensor has the temperature sensitivity coefficient of 29.16 pm/°C and 28.33 pm/°C, the temperature accuracy of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\pm 0.3~^{\circ }$ </tex-math></inline-formula> C, the response time of 0.28 and 0.40 s, the overall weight of 90.12 g, and the volume of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Phi 2.97\times 28.10$ </tex-math></inline-formula> mm, so as to ensure the accuracy of the temperature monitoring system.