Liquid flow motion rate measuring method, based on the fiber Bragg gratings

The paper presents the study of the possibilities of optical monitoring of the fluid flow velocity. An optical fiber with an array of Bragg fiber gratings, the central wavelengths of which varied depending on the velocity of the transmitted stream, was used as a sensitive element. The advantage of the developed method lies in the possibility of additional simultaneous measurement of the temperature of the liquid—which allows us to produce hot-wire anemometers, or to exclude the influence of temperature on measurements of the flow velocity. The sensitivity of the developed method was 697 pm/(m/s).