Detection system for pressure response and pressure distribution in spiral pipeline

Abstract

The invention discloses a detection system for pressure response and pressure distribution in a spiral pipeline. The system is used for detecting pressure and pressure response millisecond-level precision. The system comprises a light source module comprising a broadband light source and a polarized light source; a light source control module used for controlling the light source module to periodically emit a broadband light signal or emit a polarized light signal with a preset incident angle; a fiber grating sensing detection module which comprises an optical fiber and a fiber grating pressure sensor group; a data acquisition module which is used for acquiring the central wavelength variation of broadband optical signals reflected by a fiber grating group on one side in each grating pressure sensor, or acquiring Stokes parameters of polarized light signals transmitted by the fiber grating group on the other side in the respective characteristic grating stop-band wavelength range of each grating pressure sensor; and a computer system which is used for controlling the polarized light source in the light source module to periodically emit polarized light signals with different characteristic frequencies, or controlling the broadband light source to emit periodic broadband light signals through the light source control module.

Description

technical field [0001] The present application relates to the field of hydraulic technology, in particular to a detection system for pressure response and pressure distribution in spiral pipelines. Background technique [0002] With the popularization and application of hydraulic systems, the role of hydraulic pipelines has gradually expanded from just for reliable transmission of kinetic energy to auxiliary hydraulic system heat dissipation, auxiliary absorption of hydraulic pulsation, auxiliary energy storage and other multi-functional and multi-purpose directions. [0003] When designing the hydraulic pipeline, it can be set as a helical tube structure. The helical tube is better than the straight tube in resisting the propagation of hydraulic shock pulsation along the pipeline, and has a certain energy storage function and timely release characteristics, which can play a role Peak-shaving and valley-filling effect. [0004] At present, when the internal pressure of the ...

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Problems solved by technology

[0005] However, there are certain problems in this method: first, the structure of the side wall of the pipeline is destroyed; second, the radial sensor probe destroys the laminar flow form of the inner wall liquid flow, increasing the internal disturbance of the liquid flow; third, the internal disturbance of the spiral pipeline The outside flow velocity is different and the pressure state is different. It is difficult to accurately measure the pressure distribution and change law in the pipeline by using a fixed pressure sensor probe.

For example, when the fiber optic shed is subjected to an external field (stress field, temperature field, etc.), its grating period or effective refractive index will change, which will cause the drift of the reflection (or transmission) wavelength of the grating. Most of the fiber Bragg grating sensors belong to this category; the second is that the polarization characteristics of the fiber Bragg grating can establish a linear relationship with the physical quantity to be measured, and the polarization characteristics change with the change of the physical quantity to be measured, so that the fiber Bragg grating can be used under pressure load conditions. The resonance wavelength splitting of the method detects the external pressure by shifting the center wavelength of the amplitude spectrum of x-polarized light and y-polarized light, but this method is difficult to detect the two kinds of total amplitude spectrum when the pressure is small. The difference in the central wavelength of the eigenmode is difficult to detect

[0008] To sum up, because of the high sensitivity of the fiber grating sensor itself, no matter whether it is using the grating center wavelength drift or the birefringence detection method caused by the elliptic deformation of the fiber, there is one that can only detect the low-voltage range, and one that can only detect the relative High pressure range, so that the range of measuring pressure is greatly limited, resulting in the current lower limit or upper limit of the pressure that can be detected by the fiber grating sensor can not meet the actual needs of engineering hydraulic machinery

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