Fiber Bragg Grating Target Flow Sensor Based on Fixed Beam and Lever Structure

A novel fiber Bragg grating (FBG) flow sensor with high sensitivity is proposed in this article, which consists of a target disk, a solid beam, an L-shaped lever structure, and dual FBG. The dual-FBG configuration can simultaneously detect temperature and flow velocity. The relationship between the flow velocity and the FBG central wavelength is theoretically derived, and the simulation analysis verifies the feasibility of the sensor and optimizes its structure. Then, the sensing performance of the sensor is experimentally demonstrated. In measurement, the flow resolution reaches 0.024 L/s in the flow velocity range of 500–2500 L/h, and the temperature sensitivity reaches 25.7 pm/°C in the temperature range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$30~^{\circ }$ </tex-math></inline-formula>C–<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$210~^{\circ }$ </tex-math></inline-formula>C. The proposed FBG flow sensor in this article offers a perspective for measuring the flow velocity and temperature of oil and gas wells or oil pipelines.