A liquid density measurement device and measurement method based on side hole optical fiber

Abstract

The invention provides a liquid density measuring device based on a side-hole optical fiber and a measurement method thereof, which belong to the field of liquid density measurement. The liquid density measuring device is mainly based on two optical fiber microstructures that are welded with a side-hole optical fiber and a single-mode optical fiber. In particular, it is necessary to write gratings on the side-hole fiber. By inserting two side-hole fibers with air holes of different sizes into the liquid to be measured, the amount of liquid entering the air hole of the side-hole fiber can be measured according to the reflection spectrum of the fiber microstructure. By analyzing the force of the liquid in this part and comparing the force analysis of the liquid in the two optical fiber microstructure devices, the liquid density and surface tension coefficient can be calculated.

Description

technical field [0001] The invention relates to a liquid density measuring device based on a side hole optical fiber and a measuring method thereof, belonging to the field of liquid density measurement. Background technique [0002] Different liquids have different densities due to differences in intrinsic properties, or the same liquid in different states. The measurement of liquid density is of great significance in basic theoretical research and engineering applications. It is widely used in oil exploration and transportation, blood In the process of medical testing, battery electrolyte performance testing, aerospace liquid fuel testing, etc. [0003] According to the development status of liquid density measurement technology, the density measurement methods can be roughly divided into the following points: resonance type, ray type, ultrasonic type, capacitive type, optical fiber sensor type, etc. Among them, the resonant liquid density measuring device mainly realizes ...

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Problems solved by technology

Among them, the resonant liquid density measurement device mainly realizes the measurement through the liquid affecting the natural frequency of the measurement system. Its performance is affected by the elastic element, and its volume is relatively large. It cannot measure the density of trace liquids, and it needs to be suppressed or filtered. All kinds of mechanical vibration; the ray type is very harmful to the health of the operator; the ultrasonic liquid density measurement method is widely used and is often used as a sensor device, especially the surface acoustic wave sensor developed on the basis of ultrasonic measurement technology. Hot research directions, especially the lamb wave sensor, which is relatively smaller in size and higher in sensitivity, but the manufacturing process of the ultrasonic probe is relatively stricter and more complicated, and the ultrasonic measurement method is greatly affected by temperature and liquid purity; capacitive liquid density The measurement method mainly uses the buoyancy of the float in the liquid to convert it into the distance between the capacitor plates to achieve density measurement. Such a device has relatively high requirements on the circuit and has poor anti-interference ability; liquid density measurement using optical fiber sensing The device includes a fiber grating [Idris S K, Haroon H, Razak H A, et al. Investigation on fiber optic sensor using FBG for various temperature and liquid density [J]. Journal of Physics Conference Series, 2020, 1502: 012009.] and a fiber optic ring [Bai D, Hu S, Xu T, et al.A novel density sensor based on high-birefringence fiber loop mirror[J].Proceedings of SPIE-The International Society for Optical Engineering,2013,8914:89140G.], etc., can realize liquid density measurement , but the system is relatively complex, and the acquisition and demodulation of the signal is relatively difficult, especially the amount of liquid required for measurement is relatively large

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