Research On Key Technology Of Multi-Parameter Fiber Sensing Network For Industrial Process Monitoring

For the acquisition of data-driven industrial process monitoring parameters in complex environments,compared with traditional sensors,the use of fiber grating sensor network has the advantages of small size,flexibility,good flexibility,electromagnetic resistance,long transmission distance,corrosion resistance,convenient for nondestructive testing embedded in materials or structures,wide dynamic range,high sensitivity,and suitable for high temperature,high pressure,and acidic environments.The research on the networking of large-capacity narrow-band fiber grating sensor network is a key step in the construction of industrial process monitoring system,and is also the most fundamental and urgent problem to be solved.Based on the coupling matrix theory of fiber Bragg grating,this paper has carried out the relevant theoretical research on the refractive index modulation principle of fiber Bragg grating,the characteristic parameter analysis of fiber Bragg grating and the multiplexing technology of fiber Bragg grating,and has analyzed the waveguide characteristics of different types of fiber Bragg grating in detail on the basis of the studied nonuniform fiber Bragg grating theory.On the research of cross sensitivity of fiber Bragg grating,based on the original structure of non-uniform fiber Bragg grating,the coupling mode transfer matrix of fiber Bragg grating is extended to the subspace cascade,and the refractive index representation method and waveguide transfer matrix of the subspace cascade are studied,and the theoretical expression of refractive index division coding modulation is obtained,In addition,a refractive index division coded modulation model is proposed to control the distribution of the echo spectrum.By setting the type,number of segments,parameters and arrangement of the sub-fiber Bragg grating,the spectral distribution of the echo can be freely controlled.The fiber Bragg grating based on the refractive index coding modulation can effectively control the spectral distribution of the echo,and can solve the problem of the single echo information of the traditional fiber Bragg grating.For the solution of the cross-sensitivity problem,in addition to the temperature compensation or the simultaneous measurement of the strain and temperature parameters,it provides another feasible solution.The wavelength division multiplexing technology requires that each optical fiber Bragg grating in the optical fiber sensing network has its own independent working area and the adjacent spectrum does not overlap with each other in the large-scale optical fiber grating network.Otherwise,it will lead to the crosstalk of the central wavelength and directly affect the detection results of the sensor network.Based on the research of fiber Bragg grating network multiplexing technology,in order to solve the crosstalk problem of fiber Bragg grating under a certain bandwidth,this paper designs a fiber Bragg grating sensor network based on wavelength division multiplexing of light intensity,and proposes a model of fiber Bragg grating reflection spectrum training in different strain steps based on depth learning,which is used for wavelength detection of overlapping spectrum Bragg grating,The model can also accurately predict the Bragg wavelength of each fiber in the partial or total overlapping spectra of three or more fiber Bragg gratings.On this basis,in order to improve the peak-finding accuracy in spectral data and find the correct sensor peak in crosstalk and sidelobe,small power crosstalk can be suppressed by setting absolute threshold and relative threshold.By taking advantage of the fact that the crosstalk bandwidth is less than the sensor bandwidth under certain attenuation,it is necessary to use width attenuation and recognition width to suppress large power crosstalk signals.In the multi-FBG sensor network,the state information of the structure is obtained by networking the FBGs at different positions in the three-dimensional space.Under the condition of temperature calibration,the calculation of three-dimensional stress field can be realized.At the same time,according to the three-axis fusion solution method with temperature compensation,the three-dimensional position offset of the structure is calculated,which verifies that the network has certain advantages in three-dimensional structure condition monitoring.In the aspect of using fiber Bragg grating sensor network to monitor industrial process equipment,the packaging of sensors,the contact form of sensors and equipment,and the laying of sensors are important means to improve the measurement accuracy.On the basis of studying the distribution of temperature conduction heat field and stress field of industrial process equipment,the optimal distribution form of fiber Bragg grating sensors is calculated,and the fiber Bragg grating sensors are determined in the optical fiber network,The acquisition and reconstruction of space vector physical field can be realized with different deployment directions and locations.In the distributed fiber Bragg grating network monitoring system of industrial process equipment,each physics has better performance advantages and application significance compared with traditional equipment in terms of test accuracy,test range and response speed.Aiming at the application of distributed fiber bragg grating sensor network in industrial process monitoring,this paper studies the application of distributed fiber bragg grating sensor network in ethanol distillation process based on the background of ethanol distillation industrial process.Firstly,the measuring principle of optical fiber sensor and the process design in ethanol distillation industry are introduced.On this basis,the network of distributed optical fiber sensor network in ethanol distillation process is designed,and the process flow and main monitoring parameters of ethanol distillation are introduced in detail.The purpose of this application research is to analyze the feasibility of using distributed fiber bragg grating sensor network to monitor the parameters of ethanol distillation process,so as to give full play to the environmental adaptability and measurement accuracy of the fiber bragg grating sensor network,and provide more solutions and possibilities for industrial process monitoring.In view of the complex parameter data of industrial process,the ethanol distillation process is introduced as a typical process monitoring.Based on its application background,the input and output models of the sensor are obtained through the scaling transformation of the measured physical quantities.In order to improve the accuracy and sensitivity of the measurement,temperature compensation and differential fiber grating strain gauges are used.According to the experimental data collection and data analysis,the measured data of temperature,pressure,liquid level and flow are superior to traditional instruments in terms of accuracy and response time,which verifies the feasibility,accuracy and timeliness of the method,and provides an effective solution for monitoring the physical parameters of industrial processes.The content of this paper is to solve the key problems in the application of distributed fiber Bragg grating network in industrial process monitoring,such as the cross-sensitivity of temperature and pressure of fiber Bragg grating,the study of spectral overlap within a certain bandwidth under wavelength division multiplexing technology,the improvement of peak finding accuracy of fiber Bragg grating spectral data,and the improvement of the calculation accuracy of three-dimensional surface stress field of industrial equipment The layout of distributed fiber grating network in industrial process equipment and the application of distributed fiber grating network in ethanol distillation process monitoring have important theoretical value and guiding significance.