Abstract
This paper introduces the use of a Rayleigh backscatter-based distributed fiber optic sensor to map the temperature field in air flow for a thermal fatigue application. The experiment involves a pair of air jets at 22 and 70 degrees C discharging from 136 mm hexagonal channels into a 1 x 1 x 1.7 m tank at atmospheric pressure. A 40 m-long, phi 155 mu m fiber optic sensor was wound back and forth across the tank midplane to form 16 horizontal measurement sections with a vertical spacing of 51 mm. This configuration generated a 2D temperature map with 2800 data points over a 0.76 x 1.7 m plane. Fiber optic sensor readings were combined with PIV and infrared measurements to relate flow field characteristics to the thermal signature of the tank lid. The paper includes sensor stability data and notes issues encountered using the distributed temperature sensor in a flow field. Sensors are sensitive to strain and humidity, and so accuracy relies upon strict control of both.
