CN116519629A - TDLAS measurement signal spectral line parameter acquisition method in high-pressure environment - Google Patents
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Abstract
The invention relates to a tunable semiconductor laser absorption spectrum (TDLAS) method, in particular to a TDLAS measurement signal spectral line parameter acquisition method in a high-pressure environment, which solves the technical problems that the existing TDLAS technology has difficult baseline removal and larger spectral line parameter calculation error in the high-pressure environment. The TDLAS measurement signal spectral line parameter acquisition method in the high-pressure environment comprises the following steps: step 1) obtaining a TDLAS measurement signal I exp (v x ) The method comprises the steps of carrying out a first treatment on the surface of the Step 2) constructing a whole fitting model; step 3) determining initial values and limiting intervals of variable parameters in the integral fitting model; step 4) optimizing the variable parameters in the integral fitting model according to the initial value and the limiting interval of the variable parameters, and inverting to obtain the integral fitting model and a TDLAS measurement signal I exp (v x ) Spectral line parameters under optimal matching; the complex baseline removing process of the original signal is effectively avoided, the applicability of the TDLAS technology in a high-pressure environment is improved, and the calculation error of spectral line parameters is remarkably reduced.
Description
Technical Field
The invention relates to a tunable semiconductor laser absorption spectrum (TDLAS) method, in particular to a TDLAS measurement signal spectral line parameter acquisition method in a high-pressure environment.
Background
TDLAS (Tunable Diode Laser Absorption Spectroscopy), i.e. tunable semiconductor laser absorption spectrum technology, is to scan the characteristic absorption spectrum line of the gas molecule to be measured by using laser with extremely narrow line width to realize in-situ on-line non-contact measurement of the physical quantities such as temperature, concentration and pressure of the component to be measured. In recent years, miniaturized light sources such as near infrared band DFB (Distributed Feed Back ) diode lasers and the like are rapidly developed, and the problems of a laser source and laser detection in the TDLAS technology are gradually solved. Meanwhile, with the increasing perfection of a molecular absorption spectrum database, the TDLAS technology has become an important development direction in the field of non-contact diagnosis of complex physical fields by virtue of the advantages of high measurement precision, high sensitivity, strong anti-interference capability, compact structure of a measurement device and the like, and is widely applied to gas parameter measurement.
TDLAS is an application of absorption spectroscopy technology, which follows the basic principle of beer-lambert law, and can be expressed simply as: when the propagation distance of the monochromatic light with the frequency v in the uniform medium is L, the emergent light intensity I (v) of the monochromatic light can be used as the incident light intensity I which passes through the same path but is not absorbed 0 (v) The spectral line absorption coefficient alpha (v) and the absorption path length L, i.e. I (v) =I 0 (ν)·e -α(ν)·L . Wherein the spectral line absorption coefficient alpha (v) is related to the ambient temperature T, the pressure P, the type of the medium component to be measured and the mole fraction X. Considering only a single spectral line, the spectral line absorption coefficient α (v) is the product of the pressure P, the mole fraction X, the spectral line intensity S (T) and the normalized linear function f (v), i.e., I (v) =i 0 (ν)·e -PXS(T)f(ν)L . To achieve spectral line parameter inversion, it is common toThe logarithmic difference between the emergent light intensity and the incident light intensity is calculated to obtain the spectral line type distributionThis step is also called the "de-baselined" process of the original signal, the mathematical expression +.>In principle, two physical quantities are known for TDLAS signal processing, namely the emergent light intensity I (v) of the signal light passing through the medium to be measured and the incident light intensity I passing through the same path but not absorbed 0 (v)。
In severe application environments such as engine combustion flow field, the incident light intensity I is required to be accurately obtained 0 (v) It is very difficult. The methods commonly used at present are as follows: 1) Fitting the weak absorption part of the edge of the original signal to the incident light intensity I 0 (v) The method comprises the steps of carrying out a first treatment on the surface of the 2) Measuring non-absorption light path signal as reference incident light intensity I 0 (v) The method comprises the steps of carrying out a first treatment on the surface of the 3) Smoothing or filtering the original signal to obtain approximate incident light intensity I 0 (v) A. The invention relates to a method for producing a fibre-reinforced plastic composite The method requires that the output stability, the wavelength scanning range, the gas pressure, the component concentration and the like of the laser meet certain conditions, for example, 1) the method requires that the wavelength scanning range of the laser covers more than 10 times of line width to reduce fitting errors, 2) the method requires that the laser scanning repeatability is better and the environmental conditions of a reference light path and a signal light path are completely consistent, and 3) the method requires that the frequency component of an absorption signal is obviously higher than the light source intensity spectrum to effectively extract the incident light intensity I 0 (v) A. The invention relates to a method for producing a fibre-reinforced plastic composite In a high-pressure environment, the calculation errors of the method are increased due to light path offset, spectral line pressure broadening and the like, and the problem is often complicated to solve through experimental technology. In order to efficiently invert the characteristic parameters of the absorption spectrum and avoid the baseline removal process of the original signal, georg Schulze et al, belonging to the university of Columbia, attempt to automatically identify the incident light intensity I by training a convolutional neural network 0 (v) However, from the results, it is still difficult to achieve the desired effect.
In summary, the existing TDLAS technology has the problems of complex signal baseline removal process and large spectral line parameter calculation error in a high-pressure environment.
Disclosure of Invention
The invention aims to solve the technical problems that the existing TDLAS technology has difficult baseline removal and larger calculation error of spectral line parameters in a high-pressure environment, and provides a TDLAS measurement signal spectral line parameter acquisition method in the high-pressure environment, which can effectively avoid the complex baseline removal process of an original signal, improve the applicability of the TDLAS technology in the high-pressure environment and obviously reduce the calculation error of spectral line parameters.
The conception of the invention is as follows:
based on the wavelength response characteristic of the linear tuning region of the DFB laser, an integral fitting model comprising a base line and spectral lines is constructed and can be used for directly fitting the TDLAS original signal, so that all spectral line parameters are obtained through one-time inversion.
In order to solve the technical problems and realize the inventive concept, the invention adopts the following technical scheme:
the TDLAS measurement signal spectral line parameter acquisition method in the high-pressure environment is characterized by comprising the following steps of:
step 1) using linear current to drive a DFB laser to obtain an output light beam with the light intensity changing linearly along with time, controlling the temperature of the DFB laser to enable the wavelength tuning range of the output light beam to cover a spectral line, and obtaining a TDLAS measuring signal I after the output light beam is transmitted through an absorption medium in an environment to be measured exp (v x )；
Step 2) construction comprising the intensity of incident light I 0 (v x ) Spectral line absorption coefficient alpha (v x ) A global fitting model co-acting with the absorption path length L;
step 3) measuring the signal I according to the environment to be measured and the TDLAS exp (v x ) Determining initial values and limiting intervals of variable parameters in the integral fitting model;
step 4) fitting TDLAS measurement signal I by adopting nonlinear curve according to the initial value and the limiting interval of the variable parameter exp (v x ) And optimizing variable parameters in the integral fitting model by taking the minimum MSE as a target, and inverting to obtain the integral fitting model and a TDLAS measurement signal I exp (v x ) Best matchThe spectral line parameters below.
Further, in step 2), the integral fitting model specifically includes:
wherein I (v) x ) For the intensity of the outgoing light, k 3 、k 2 、k 1 、k 0 For incident light intensity I 0 (v x ) A is the area corresponding to the line approximate line type Lorentz function, deltav is the line width corresponding to the line approximate line type Lorentz function, v 0 Sampling point coordinates corresponding to the center of the line-approximation line-type Lorentz function, v x Measuring signal I for single period TDLAS exp (v x ) And x represents the serial number of the sampling point, and 0 represents the approximate linear Lorentz function center of the spectral line.
Further, in step 3), the variable parameter specifically includes the incident light intensity I 0 (v x ) The third order polynomial fit coefficient k 3 、k 2 、k 1 、k 0 Area A, line width Deltav and center v of Lorentz function similar to spectral line 0 。
Further, the step 3) specifically comprises:
3.1 Pretreatment of TDLAS measurement signal I using baseline fitting method exp (v x ) Obtaining the incident light intensity I 0 (v x ) The third order polynomial fit coefficient k 3 、k 2 、k 1 、k 0 Is the initial value of (2);
3.2 By calculating ln (I) 0 (v x )/I exp (v x ) Obtaining a spectral line profileLine profile>Integration of the abscissa as the initial value of the area A, the spectral line profile is +.>As an initial value of the line width Deltav, the line profile is +.>The abscissa corresponding to the peak of (2) is taken as the center v 0 Is the initial value of (2);
3.3 To fit coefficient k 3 、k 2 、k 1 、k 0 Initial value of (a) and initial value of area a, initial value of line width Δv, center v 0 Setting a fitting coefficient k by combining the initial value of the environment to be measured as a reference and the dynamic range of the environment to be measured 3 、k 2 、k 1 、k 0 Area A, line width Deltav and center v 0 Is a limited zone of (2); the dynamic range of the environmental change to be measured includes temperature, pressure and concentration of the component to be measured.
Further, step 3.1) specifically includes:
pretreatment of TDLAS measurement signal I using baseline fitting method exp (v x ) Measuring signal I using TDLAS exp (v x ) The weak absorption parts at the two sides are subjected to polynomial fitting for three times, optimization iteration is carried out by taking the MSE as the minimum target, and the incident light intensity I is obtained 0 (v x ) Fitting coefficient k of (2) 3 、k 2 、k 1 、k 0 Is the initial value of (2);
the weak absorption part is measured by TDLAS exp (v x ) The spectral line absorption center position of (2) is used as a starting point, the rest data of 5 times of line width length is deleted in a front-back symmetrical way, or a TDLAS measuring signal I is selected exp (v x ) Data of 10% each of the first and last middle were used as weak absorption portions.
Further, the step 4) specifically comprises:
4.1 According to the fitting coefficient k 3 、k 2 、k 1 、k 0 And area A, line width Deltav, center v 0 Is fitted to the TDLAS measurement signal I by using a Levenberg-Marquardt algorithm exp (v x )；
4.2 To all are equal toThe MSE is the minimum target, and the incident light intensity I in the integral fitting model is iteratively optimized 0 (v x ) The third order polynomial fit coefficient k 3 、k 2 、k 1 、k 0 And area A, line width Deltav, center v 0 The integral fitting model and the TDLAS measuring signal I are obtained through inversion exp (v x ) Area A, line width Deltav, center v under best match 0 ：
Wherein n is a single period TDLAS measurement signal I exp (v x ) Is a sampling point of (c).
Further, in step 3.1), the optimization iteration number is 200, and the incident light intensity I 0 (v) Fitting coefficient k of (2) 3 、k 2 、k 1 、k 0 The initial values of the components are 1.08E-10, -3.76E-7, 2.98E-3 and 0.68 respectively.
Further, in step 3.2), the area A, the line width Deltav and the center v 0 Initial values of 8.95, 78.84, 252, respectively.
Further, in step 3.3), the fitting coefficient k 3 、k 2 、k 1 、k 0 Area A, line width Deltav and center v 0 The restriction intervals of (a) are [ -1E-9,1E-9 respectively]、[-1E-6,1E-6]、[-0.01,0.01]、[-1,1]、[0,100]、[0,400]、[230,270]。
Further, in step 4.2), the ensemble fitting model is fitted to the TDLAS measurement signal I exp (v x ) Area A, line width Deltav, center v under best match 0 12.63, 83.48, 250.08, respectively.
Compared with the prior art, the technical scheme of the invention has the beneficial effects that:
1. according to the TDLAS measurement signal spectral line parameter acquisition method in the high-pressure environment, the original signal (namely the output light beam) is subjected to integral fitting, so that the incident light intensity and the spectral line linear distribution are acquired simultaneously. Compared with the traditional data processing method, the spectral line type inversion precision in a high-pressure environment can be obviously improved, and the accuracy of spectral line parameter calculation results is improved.
2. The method for acquiring the spectral line parameters of the TDLAS measurement signal in the high-pressure environment is wide in application range, the working condition can cover negative pressure to high pressure, accurate calculation of the spectral line parameters can be realized by setting a reasonable limiting interval, and the problem of baseline removal of the TDLAS original signal is effectively solved without adding an optical path measurement reference signal.
Drawings
FIG. 1 is a flowchart of an embodiment of a method for obtaining parameters of spectral lines of TDLAS measurement signals in a high-pressure environment according to the present invention;
FIG. 2 shows the measured CO at 1.3atm in example 1 of the present invention 2 Molecule 5 period TDLAS measurement Signal I at 1572.34nm exp (v x ) A schematic diagram;
FIG. 3 is a diagram showing the processing of the TDLAS measurement signal I by the baseline fitting method in an embodiment of the present invention exp (v x ) Schematic of (2);
FIG. 4 shows ln (I) 0 (v x )/I exp (v x ) Line profile for inversionA schematic diagram;
FIG. 5 shows the TDLAS measurement signal I of the present invention exp (v x ) Schematic drawing of integral fitting;
FIG. 6 is a diagram of an inversion of the overall fitting model and TDLAS measurement signal I in an embodiment of the invention exp (v x ) Area A, line width Deltav, center v under best match 0 Schematic of (2);
FIG. 7 is a graph showing a conventional baseline fit and overall fit of the example for treatment of TDLAS measurement signal I at 5.3atm exp (v x ) Is a comparative schematic of (1);
FIG. 8 is a graph showing the contrast of the line patterns inverted at 5.3atm for a conventional baseline fit and the overall fit in the examples.
Detailed Description
As shown in fig. 1, a TDLAS measurement signal spectral line parameter acquiring method in a high-pressure environment is characterized by comprising the following steps:
step 1) using sawtooth current with linear current of 30mA and frequency of 200Hz to drive DFB laser to obtain output beam with linear change of light intensity along with time, and controlling temperature of DFB laser to make wavelength tuning range of output beam cover CO 2 A spectral line with a molecular center wavelength of 1572.34 nm;
as shown in FIG. 2, the CO-passing is received with a photodetector at a room temperature of 1.3atm 2 Output signal with concentration of 50% and absorption path length of 1.3m is recorded in real time by data acquisition equipment, sampling rate is set to 100kHz, and TDLAS measurement signal I is obtained exp (v x )。
Step 2) construction comprising the intensity of incident light I 0 (v x ) Spectral line absorption coefficient alpha (v x ) A global fitting model that works together with the absorption path length L:
wherein I (v) x ) For the intensity of the outgoing light, k 3 、k 2 、k 1 、k 0 For incident light intensity I 0 (v x ) A is the area corresponding to the line approximate line type Lorentz function, deltav is the line width corresponding to the line approximate line type Lorentz function, v 0 Sampling point coordinates corresponding to the center of the line-approximation line-type Lorentz function, v x Measuring signal I for TDLAS exp (v x ) And x represents the serial number of the sampling point, and 0 represents the approximate linear Lorentz function center of the spectral line.
Step 3), measuring the signal I according to the environment to be measured, the DFB laser characteristic and the TDLAS exp (v x ) The initial characteristics of (a) shows that the DFB laser is in a linear tuning state, and the output light intensity and wavelength change linearly with time. Measuring signal I according to the environment to be measured and TDLAS exp (v x ) Setting initial values and a limiting interval of variable parameters in the integral fitting model, wherein the variable parameters are fitting coefficients k 3 、k 2 、k 1 、k 0 Initial value of (a) and initial value of area a, initial value of line width Δv, center v 0 . The method comprises the following steps:
3.1 As shown in FIG. 3, the TDLAS measurement signal I is first processed by a baseline fitting method exp (v x ) For easy calculation, directly select TDLAS measurement signal I exp (v x ) Three polynomial fits were performed with 10% of the data from the beginning to the end of the middle as the weak absorption portion (in other embodiments, measuring signal I with TDLAS may also be used exp (v x ) The rest data of 5 times of linewidth length is deleted back and forth symmetrically as the starting point, the three times polynomial fitting is carried out on the weak absorption part, the MSE is taken as the target, the maximum optimization iteration number is set as 200, and the incident light intensity I is calculated 0 (v x ) Fitting coefficient k of (2) 3 、k 2 、k 1 、k 0 The initial values of (2) are respectively: 1.08E-10, -3.76E-7, 2.98E-3, 0.68;
3.2 As shown in FIG. 4, ln (I) 0 (v x )/I exp (v x ) Obtaining a spectral line profileWill->Integrating the abscissa as the initial value of area A, +.>Is used as the initial value of the line width Deltav, & lt + & gt>The abscissa corresponding to the peak value is taken as the center v 0 The initial values of (2) are calculated by the following formulas, and the obtained results are respectively: 8.95, 78.84, 252;
3.3 To fit coefficient k 3 、k 2 、k 1 、k 0 Initial value of (a) and initial value of area a, initial value of line width Δv, center v 0 At the same time, the fitting coefficient k is set according to the dynamic range of the environmental change to be measured 3 、k 2 、k 1 、k 0 Area A, line width Deltav and center v 0 The results are respectively: [ -1E-9,1E-9]、[-1E-6,1E-6]、[-0.01,0.01]、[-1,1]、[0,100]、[0,400]、[230,270]In this embodiment, the dynamic range of the environmental change to be measured includes pressure and CO 2 Concentration.
Step 4) fitting TDLAS measurement signal I by adopting nonlinear curve according to the initial value and the limiting interval of the variable parameter exp (v x ) And optimizing variable parameters in the integral fitting model by taking the minimum MSE as a target, and inverting to obtain the integral fitting model and a TDLAS measurement signal I exp (v x ) Spectral line parameters under optimal matching, i.e. area A, line width Deltav n And center v 0 Is a solution to the optimization of (3).
4.1 According to the fitting coefficient k 3 、k 2 、k 1 、k 0 Initial value of (a) and initial value of area a, initial value of line width Δv, center v 0 Is fitted to the TDLAS measurement signal I by using a Levenberg-Marquardt algorithm exp (v x )；
4.2 Aiming at the minimum of the mean square error MSE), iteratively optimizing the incident light intensity I in the integral fitting model 0 (v x ) Is fitted to the parameter k by a polynomial of degree three 3 、k 2 、k 1 、k 0 And area A, line width Deltav, center v 0 Setting the maximum optimization iteration number as 200, and obtaining the integral fitting model through inversion as shown in fig. 5 and 6And TDLAS measurement signal I exp (v x ) Area A, line width Deltav, center v under best match 0 Is the optimal solution of (a):
wherein n is a single period TDLAS measurement signal I exp (v x ) Is a sampling point of (c).
To avoid TDLAS measurement signal I exp (v x ) The nonlinear parts on two sides influence the calculation accuracy, and the effective data point interval of the monocycle signal selected during fitting is [30, 480 ]]Obtaining the final area A, the line width Deltav and the center v 0 The optimal solutions of (a) are respectively: 12.63, 83.48, 250.08. The method solves the problem of TDLAS measurement signal I in high-pressure environment exp (v x ) The method is suitable for absorption spectrum line type calculation and parameter inversion under the wide working condition.
To verify the reliability of the process of the invention, the same temperature, CO 2 TDLAS measurement signal I under concentration and different pressure environments exp (v x ) The operations of the above steps 2) to 4) are performed. By comparing the processing results of the traditional baseline fitting method with the predicted data given by the absorption spectrum theoretical model, the measurement errors and the change trend of the area A and the line width Deltav can be obtained, as shown by comparing the results of the TDLAS measurement signals of different pressures processed by the baseline fitting and the integral fitting in the table 1:
table 1 baseline fitting and overall fitting processing of different pressure TDLAS measurement signals I exp (v x ) Comparison of results
As can be seen from the table 1, as the pressure increases, the error of the baseline fit gradually increases, while the overall fit result error is smaller and is to some extent hardly affected by pressure changes.Two methods of processing TDLAS measurement signal I at 5.3atm exp (v x ) As shown in FIG. 7 and FIG. 8, due to the I under high-pressure broadening of the conventional baseline fitting method 0 (v x ) The fitting amplitude is lower, so that the calculated spectral line absorption intensity is weaker, and the method is realized by directly fitting I (v x ) In a manner that effectively ameliorates this problem.
Claims (10)
1. The TDLAS measurement signal spectral line parameter acquisition method in the high-pressure environment is characterized by comprising the following steps:
step 1) using linear current to drive a DFB laser to obtain an output light beam with the light intensity changing linearly along with time, controlling the temperature of the DFB laser to enable the wavelength tuning range of the output light beam to cover a spectral line, and obtaining a TDLAS measuring signal I after the output light beam is transmitted through an absorption medium in an environment to be measured exp (v x )；
Step 2) construction comprising the intensity of incident light I 0 (v x ) Spectral line absorption coefficient alpha (v x ) A global fitting model co-acting with the absorption path length L;
step 3) measuring the signal I according to the environment to be measured and the TDLAS exp (v x ) Determining initial values and limiting intervals of variable parameters in the integral fitting model;
step 4) fitting TDLAS measurement signal I by adopting nonlinear curve according to the initial value and the limiting interval of the variable parameter exp (v x ) And optimizing variable parameters in the integral fitting model by taking the minimum MSE as a target, and inverting to obtain the integral fitting model and a TDLAS measurement signal I exp (v x ) Spectral line parameters under the best match.
2. The method for obtaining TDLAS measurement signal spectral line parameters under high-pressure environment according to claim 1, wherein in step 2), the integral fitting model is specifically:
wherein I (v) x ) For the intensity of the outgoing light, k 3 、k 2 、k 1 、k 0 For incident light intensity I 0 (v x ) A is the area corresponding to the line approximate line type Lorentz function, deltav is the line width corresponding to the line approximate line type Lorentz function, v 0 Sampling point coordinates corresponding to the center of the line-approximation line-type Lorentz function, v x Measuring signal I for single period TDLAS exp (v x ) And x represents the serial number of the sampling point, and 0 represents the approximate linear Lorentz function center of the spectral line.
3. The TDLAS measurement signal spectral line parameter acquisition method under a high-pressure environment according to claim 2, wherein:
in step 3), the variable parameters include in particular the intensity of incident light I 0 (v x ) The third order polynomial fit coefficient k 3 、k 2 、k 1 、k 0 Area A, line width Deltav and center v of Lorentz function similar to spectral line 0 。
4. A method for obtaining TDLAS measurement signal spectral line parameters in a high-pressure environment according to claim 3, wherein step 3) specifically comprises:
3.1 Pretreatment of TDLAS measurement signal I using baseline fitting method exp (v x ) Obtaining the incident light intensity I 0 (v x ) The third order polynomial fit coefficient k 3 、k 2 、k 1 、k 0 Is the initial value of (2);
3.2 By calculating ln (I) 0 (v x )/I exp (v x ) Obtaining a spectral line profileLine profile>Integration of abscissa as areaInitial value of A, spectral line type distribution +.>As an initial value of the line width Deltav, the line profile is +.>The abscissa corresponding to the peak of (2) is taken as the center v 0 Is the initial value of (2);
3.3 To fit coefficient k 3 、k 2 、k 1 、k 0 Initial value of (a) and initial value of area a, initial value of line width Δv, center v 0 Setting a fitting coefficient k by combining the initial value of the environment to be measured as a reference and the dynamic range of the environment to be measured 3 、k 2 、k 1 、k 0 Area A, line width Deltav and center v 0 Is a limited zone of (2); the dynamic range of the environmental change to be measured includes temperature, pressure and concentration of the component to be measured.
5. The method for obtaining TDLAS measurement signal spectral line parameters under high-pressure environment according to claim 4, wherein step 3.1) specifically comprises:
pretreatment of TDLAS measurement signal I using baseline fitting method exp (v x ) Measuring signal I using TDLAS exp (v x ) The weak absorption parts at the two sides are subjected to polynomial fitting for three times, optimization iteration is carried out by taking the MSE as the minimum target, and the incident light intensity I is obtained 0 (v x ) Fitting coefficient k of (2) 3 、k 2 、k 1 、k 0 Is the initial value of (2);
the weak absorption part is measured by TDLAS exp (v x ) The spectral line absorption center position of (2) is used as a starting point, the rest data of 5 times of line width length is deleted in a front-back symmetrical way, or a TDLAS measuring signal I is selected exp (v x ) Data of 10% each of the first and last middle were used as weak absorption portions.
6. The method for obtaining TDLAS measurement signal spectral line parameters under high-pressure environment according to claim 5, wherein step 4) specifically comprises:
4.1 According to the fitting coefficient k 3 、k 2 、k 1 、k 0 And area A, line width Deltav, center v 0 Is fitted to the TDLAS measurement signal I by using a Levenberg-Marquardt algorithm exp (v x )；
4.2 Aiming at the minimum of the mean square error MSE), iteratively optimizing the incident light intensity I in the integral fitting model 0 (v x ) The third order polynomial fit coefficient k 3 、k 2 、k 1 、k 0 And area A, line width Deltav, center v 0 The integral fitting model and the TDLAS measuring signal I are obtained through inversion exp (v x ) Area A, line width Deltav, center v under best match 0 ：
Wherein n is a single period TDLAS measurement signal I exp (v x ) Is a sampling point of (c).
7. The TDLAS measurement signal spectral line parameter acquisition method under a high-pressure environment according to claim 6, wherein:
in the step 3.1), the optimization iteration number is 200, and the incident light intensity I 0 (v) Fitting coefficient k of (2) 3 、k 2 、k 1 、k 0 The initial values of the components are 1.08E-10, -3.76E-7, 2.98E-3 and 0.68 respectively.
8. The TDLAS measurement signal spectral line parameter acquisition method under a high-pressure environment according to claim 7, wherein:
in step 3.2), the area A, the line width Deltav and the center v 0 Initial values of 8.95, 78.84, 252, respectively.
9. The TDLAS measurement signal spectral line parameter acquisition method under high-pressure environment according to claim 8, wherein:
in step 3.3), the fitting coefficient k 3 、k 2 、k 1 、k 0 Area A, line width Deltav and center v 0 The restriction intervals of (a) are [ -1E-9,1E-9 respectively]、[-1E-6,1E-6]、[-0.01,0.01]、[-1,1]、[0,100]、[0,400]、[230,270]。
10. The TDLAS measurement signal spectral line parameter acquisition method under a high-pressure environment according to claim 9, wherein:
in step 4.2), the ensemble fitting model is combined with the TDLAS measurement signal I exp (v x ) Area A, line width Deltav, center v under best match 0 12.63, 83.48, 250.08, respectively.
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