CN106969800A - The apparatus and method that a kind of utilization single spectral line measures gas temperature and concentration simultaneously - Google Patents
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Abstract
Gas temperature and the device of concentration are measured simultaneously the invention discloses a kind of utilization single spectral line, a kind of utilization single spectral line is also disclosed while measuring the method for gas temperature and concentration, this method first with the normalized second harmonic signal of peak value line style, the line style is determined by temperature is single, therefrom extracts the temperature of gas；The relation extracting concentration information for recycling the normalized second harmonic signal amplitude of first harmonic of background correction to be directly proportional to concentration, so as to obtain the temperature and concentration of gas simultaneously.The measuring method of the present invention can measure the temperature and concentration of gas simultaneously, the quantity of spectral line needed for reducing, and measuring method has that sensitivity is high, precision is high, response time fast advantage；Compared to the method for traditional dopplerbroadening measurement temperature, the scope of application has been expanded in the case of normal temperature and pressure；In addition, compared with the method for traditional Double-Line Method measurement temperature, it is not necessary to the problem of considering frequency crosstalk and temporal resolution.
Description
Technical Field
The invention relates to a device for simultaneously measuring gas temperature and concentration by using a single spectral line, and also relates to a method for simultaneously measuring gas temperature and concentration by using a single spectral line, belonging to the technical field of laser absorption spectroscopy.
Background
Temperature is one of the most common and important parameters in daily life and production processes. At present, the electricity supply in China still mainly uses a coal-fired power plant, the gas temperature in a boiler is monitored in real time in the combustion process, the combustion control can be optimized, the combustion efficiency and the economic benefit are improved, and the discharge amount of pollutants is reduced.
In the field of aviation, aircraft engines are the core components of aircraft, the operating conditions of which play a crucial role in the safe flight of the aircraft, while deviations of the temperature and concentration of the combustion chamber outlet gases from normal operating conditions have a significant influence on the life of the turbine guide vanes and rotor blades. Therefore, the temperature and the concentration of the gas are effectively monitored, and the occurrence of aviation accidents can be avoided as far as possible.
At present, the measurement methods of gas temperature are mainly classified into contact type and non-contact type. The thermocouple in the contact measurement method is most widely applied, and can realize continuous measurement from-50 to 1600 ℃. However, when the thermocouple is used for measurement, the probe needs to be extended into the flow field, which causes intrusion on the measurement of the temperature field, and the thermocouple has thermal inertia and slow response speed. In addition, there are occasions when the gas temperature has exceeded the thermocouple measurement range. These limitations have limited the use of thermocouples. The application of tunable semiconductor laser absorption spectroscopy (TDLAS) in the non-contact measurement method in the actual combustion environment becomes a research hotspot, and the method has the advantages of compact and durable system, good detection environment adaptability and anti-interference capability, high measurement precision, high sensitivity and high response speed.
The gas temperature measurement method commonly used in the TDLAS technique employs two methods. One is to extract the temperature of the gas by using the doppler broadening of the gas absorption line, which is a method that is difficult to accurately separate the doppler broadening and collisional broadening of the gas absorption line in practical process, and is generally used in the case of high temperature and low pressure, where the doppler broadening plays a major role. Another method is to extract the temperature of the gas by using the line intensity ratio of the two spectral lines, which is most widely used, and the temperature sensitivity depends on the low energy level difference of the absorption spectral line pair. The larger the energy level difference, the higher the temperature sensitivity. The absorption intensity of the two absorption lines in the measured temperature range is not too small, and for the absorption line with higher low energy level, the absorption intensity is often very low, so that the selection of the absorption line with higher energy level is limited; in addition, the absorption lines with lower energy levels have stronger absorption on a cold boundary layer, which limits the selection of the absorption lines with lower energy levels; in addition, in the process of measuring the gas temperature by the two-wire method, when frequency division multiplexing is adopted, two spectral lines need to select proper modulation frequencies to avoid crosstalk between the frequencies, so that the selection of the modulation frequencies by the two-wire method is limited, and the time resolution is reduced by adopting the time division multiplexing method.
Disclosure of Invention
The purpose of the invention is as follows: the invention aims to provide a method for simultaneously measuring the temperature and the concentration of gas by using a single spectral line, which is particularly suitable for real-time detection of the temperature and the concentration of the gas in a severe industrial field.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a method for measuring gas temperature and concentration simultaneously by using a single spectral line, which first uses a line profile of a peak normalized second harmonic signal, which is determined by temperature singularity, from which the temperature of the gas is extracted; and extracting concentration information by utilizing the second harmonic signal amplitude of the background-subtracted first harmonic normalization, wherein the signal amplitude is in direct proportion to the concentration, so that the temperature and the concentration of the gas are obtained simultaneously.
The single spectral line used by the method needs to satisfy the following conditions: when the temperature of the gas is constant, the absorption line type of the spectral line does not change with the concentration or changes little; at a certain concentration of the gas, the absorption line of the spectral line changes obviously along with the temperature; the foitt broadening of the spectral line is a monotonic function of temperature over the temperature range to be measured.
The method for simultaneously measuring the gas temperature and the gas concentration by using the single spectral line comprises the following steps:
step 1, processing the measured transmitted light intensity to obtain a measured peak value normalized second harmonic signal R2f/pAnd first harmonic normalized second harmonic signal R2f/1fAnd extracting R2f/1fThe initial values of the temperature and the concentration of the gas to be measured are respectively X0、T0Setting the initial value of n as 0;
step 2, for known XnChanging TnCombining the database to obtain a simulated peak normalized second harmonic signal, and fitting the measured peak normalized second harmonic signal by using a least square method to obtain Tn+1；
Step 3, for known Tn+1Changing XnCombining the database to obtain the simulated first harmonic normalized second harmonic signal and extracting different XnThe peak value is obtained by substituting p into the concentration-peak value relation of the simulation signal and obtaining the concentration X corresponding to p by using an interpolation methodn+1；
Step 4, for a sufficiently large number n, the termination criterion is satisfied:
wherein ξ is a predetermined threshold;
if yes, the iteration is terminated, and X is outputn+1、Tn+1X of outputn+1、Tn+1Respectively measuring the concentration and temperature of the gas to be measured; if the termination criterion is not met, making n equal to n +1, returning to the step 2, and repeating the steps 2 to 4 until the termination criterion is met.
In step 1, digital phase locking and low-pass filtering are performed on the measured transmitted light intensity to obtain X components and Y components of each harmonic signal of the background signal and the absorption signal, so that the second harmonic signal with the background subtracted can be extracted, and the expression is as follows:
in the formula, X2fAnd Y2fRespectively the X-component and the Y-component of the second harmonic of the absorption signal,andthe X component and the Y component of the second harmonic of the background signal, respectively, find S2fThe height p of the peak point, then the background-subtracted peak normalized second harmonic signal R2f/p＝S2f/p. Background-subtracted first harmonic normalized second harmonic signal R2f/1fThe expression is as follows:
in the formula, R1fAndthe first harmonic of the absorption signal and the background signal, respectively, is given by:
wherein, in step 2, the concentration XnWhen known, assume the temperature TnThe spectral absorbance can be simulated in combination with the information provided by the database, and the expression is as follows:
α(v(t))＝Sj·φj(ΔVC，ΔVD，v(t))·P·Xi·L
in the formula, SjAnd phijRespectively the line intensity and the line type function of the jth spectral line, P is the total pressure of the gas, XiIs the mole fraction of the ith absorption gas, and L is the path length, from which the simulated transmitted light intensity can be obtained:
SIt＝I0·exp(-α)
in the formula I0The measured background light intensity is used for obtaining the simulated transmitted light intensity, then digital phase locking and low-pass filtering processing are carried out, and the simulated peak value normalization second harmonic signal is extracted.
Wherein, in step 3, the concentration X is changed at a constant temperaturenFirst harmonic normalized second harmonic signal R combined with database simulation to subtract background2f/1fAnd extracting R2f/1fThe concentration of the peak value p is in a linear relation with the corresponding p, and the gas concentration corresponding to the peak value is determined by utilizing an interpolation method.
Compared with the prior art, the technical scheme of the invention has the beneficial effects that:
compared with the traditional gas temperature measuring method, the single-line method provided by the invention for measuring the temperature and the concentration of the gas not only keeps the characteristics of high time resolution, high precision, high signal-to-noise ratio, high sensitivity and the like, but also avoids the problems of frequency crosstalk, time resolution and the like which need to be considered in the temperature measuring process by a double-line method, and simultaneously expands the application range of measuring the temperature by Doppler broadening to the normal pressure and normal temperature; in addition, the number of the lasers used in the measuring method is less than that of the lasers used in the traditional bilinear method for measuring the temperature, so that the measuring cost is reduced; finally, the measurement method of the present invention overcomes the limitation of requiring a known temperature for single line measurement of gas concentration, as compared to conventional gas concentration measurement methods.
Drawings
FIG. 1 is a flow chart of a method of the present invention for simultaneously measuring gas temperature and concentration using a single spectral line;
FIG. 2 shows R at different concentrations in the examples of the present invention2f/pA signal;
FIG. 3 shows R at 5% concentration and different temperatures in the example of the present invention2f/pA signal;
FIG. 4 shows the relative sensitivity of temperature measurement with a concentration of 5% according to an embodiment of the present invention;
FIG. 5 shows the variation of the Fout spread at a concentration of 5% at different temperatures in an embodiment of the present invention;
FIG. 6 shows a least squares fit of R in an embodiment of the present invention2f/pA graph of results of (1);
FIG. 7 is a graph illustrating simulation of peak values at different concentrations and interpolation to obtain the concentration of the gas to be measured according to an embodiment of the present invention;
FIG. 8 is a graph comparing temperature measurements of the present invention measurement method and thermocouple measurement method at elevated temperatures;
FIG. 9 is a graph showing the results of concentration measurement by the measuring method of the present invention at a high temperature;
FIG. 10 is a schematic diagram of the apparatus of the present invention for simultaneously measuring gas temperature and concentration using a single spectral line.
Detailed Description
The technical solutions of the present invention are further described below with reference to the accompanying drawings, but the scope of the claimed invention is not limited thereto.
As shown in fig. 1, the method for simultaneously measuring the temperature and the concentration of the gas by using a single spectral line of the present invention specifically comprises the following implementation steps:
step 1, processing the measured transmitted light intensity to obtain a measured peak value normalized second harmonic signal and a measured first harmonic normalized second harmonic signal, extracting the peak value of the first harmonic normalized second harmonic signal, recording the peak value as p, and giving the initial values of the temperature and the concentration of the gas to be measured as X respectively0、T0And setting the initial value of n to 0, end condition ξ;
step 2, for known XnChanging TnCombining the database to obtain a simulated peak normalized second harmonic signal, and fitting the measured peak normalized second harmonic signal by using a least square method to obtain Tn+1；
Step 3, for known Tn+1Changing XnCombining the database to obtain the simulated first harmonic normalized second harmonic signal and extracting different XnThe peak value is obtained by substituting p into the concentration-peak value relation of the simulation signal and obtaining the concentration X corresponding to p by using an interpolation methodn+1；
Step 4, for a sufficiently large number n, the termination criterion is satisfied:
wherein ξ is a predetermined threshold;
if so, then the stack is repeatedWhen generation is terminated, X is outputn+1、Tn+1X of outputn+1、Tn+1Respectively measuring the concentration and temperature of the gas to be measured; if not, let n be n +1, update Xn←Xn+1，Tn←Tn+1And returning to the step 2, and repeating the step 2 to the step 4 until the termination criterion is met.
The single spectral line used by the method needs to satisfy the following conditions: when the temperature of the gas is constant, the absorption line type of the spectral line does not change with the concentration or changes little; at a certain concentration of the gas, the absorption line of the spectral line changes obviously along with the temperature; the foitt broadening of the spectral line is a monotonic function of temperature over the temperature range to be measured.
The absorption line profiles are mainly classified into a gaussian profile, a lorentz profile, and a foett profile according to the broadening mechanism.
The gaussian linear function, derived from random thermal motion of the absorbing molecule, can be described as:
where v is the laser frequency, v0Is the spectral center frequency.
Doppler spread DeltavDCan be calculated from equation (2):
where T is the gas temperature and M is the gas molar mass.
The Lorentzian linear function is derived from the collisional broadening mechanism and can be described as:
wherein the impact spread DeltavCCan be calculated from equation (4):
wherein P is total gas pressure, XjIs the gas concentration of component j, γjIs the collisional broadening coefficient of component j, which is temperature dependent.
Wherein X is the gas concentration, γselfIs the self-broadening coefficient, gamma, of the gas to be measuredairIs the air broadening coefficient, T0Is the reference temperature (usually T)0296K), n is a temperature dependent coefficient.
Ford linear function phiV(v) From a Gaussian linear function phiD(v) And a Lorentzian line function phiC(v) Can be described as:
φV(v)＝cL·φD(v)+cG·φC(v) (6)；
wherein, cLAnd cGRespectively, are weight coefficients.
Voit spread Δ vV：
Peak of the fuite line type:
wherein,γD＝ΔvD/2，γC＝ΔvC/2。
then the aspect ratio of the foitt line (the ratio of the foitt spread to the peak of the foitt line) can be expressed as:
in the formula,the beer-Lambert law, the fundamental law of absorption spectroscopy, characterizes the intensity of transmitted light I of a monochromatic laser beam of frequency v passing through a homogeneous gaseous medium to be measured of length L, pressure P, temperature T and concentration Xt(v) And incident light intensity I0(v) The relationship of (1):
in the formula, τvAs a transmittance, It(v) And I0(v) Representing transmitted and incident light intensities, respectively, and α (v) representing absorbance, expressed as:
α(v)＝PXLS(T)·φ(v) (11)；
in formula (11), S (T) is the line intensity of the spectral line, and φ (v) is a linear function of the gas absorption.
The scanning frequency used in the experimental process is fsSine wave superposition high modulation frequency fmThe laser is tuned by the sine wave of (a), and the laser output frequency can be expressed as:
wherein,and a is the laser center frequency and the modulation amplitude.
Meanwhile, the output light intensity variation of the laser can also be expressed as:
wherein,is the central intensity of the laser, i0And i2Linear and non-linear intensity modulation amplitudes respectively,andlinear and non-linear frequency modulation and intensity modulation, respectively.
According to the Beer-Lambert law, the Fourier series expansion of transmittance is as follows:
wherein, k order Fourier coefficient HkCan be expressed as:
after the phase locking and filtering processes, the second harmonic signal with background subtracted is:
wherein G is the gain coefficient of the detection system.
Using S2fPeak value of (c) to which peak value normalization is performed:
the measurement method provided by the invention aims at alpha (t) less than or equal to 0.1, and the formula (10) can be approximately expressed as follows:
the corresponding equation (15) is expressed as:
order toNamely, formula (17) is expressed as:
as can be seen from formula (20), R2f/pFrom a linear function phiV(t) determining a linear function phiV(t) broadening by collision by Δ vCAnd Doppler spread Δ vDAnd (4) jointly determining. Δ vCIs a function of the concentration X, the temperature T,. DELTA.vDIs a function of the temperature T. When Δ vCWhen not sensitive to concentration X, R2f/pDetermined by temperature T, according to R2f/pCan countCalculating the temperature T of the gas.
In the condition 1, when the temperature of the gas is constant, the absorption line of the spectral line does not change with the concentration or changes little.
In the condition 2, the absorption line of the spectral line changes obviously along with the temperature when the concentration of the gas is constant.
At a given concentration of gas, the R of the spectral line changes with temperature2f/pThe signal line type changes significantly. The relative sensitivity can be determined by the aspect ratio Deltav of a linear functionV_norA description is given. The relative sensitivity of the thermometry at this time can be expressed as:
and 3, in the temperature range to be measured, the Forset broadening of the spectral line is a monotonic function of the temperature.
As shown in FIG. 2, the embodiment simulates a CO2Temperature of 800K, R at different concentrations2f/pSignal, the selected spectral line satisfies condition 1. Concentration of 5% and R at different temperatures2f/pSignals are shown in FIG. 3, R2f/pThe temperature change is obvious, the relative sensitivity of temperature measurement is shown in figure 4, and the condition 2 is met. The variation of the foitt spread when the temperature is different is shown in fig. 5, and it can be seen that the foitt spread is a monotonic function of the temperature in the measured temperature range, and the condition 3 is satisfied. Based on this condition, R2f/pThe linear change of (A) is determined by temperature alone, and the single line method proposed by the present invention is used to measure CO2The temperature of (2) is feasible.
The feasibility of the method provided by the invention is tested at normal temperature. Standard gas CO2Concentration of (2) 10.02%, temperature T ═ 20.3 ℃ indicated by a thermo-hygrometer. R measured by least squares fitting2f/pExtraction of CO2See fig. 6 for the fitting results. Simulation of R at different concentrations2f/1fThe results are shown in FIG. 7. And extracting peak values under different concentrations, and obtaining the concentration of the gas to be detected by using an interpolation method. CO 22Measured temperature of TMeasuring294.50K, Standard deviation 1.12K, relative error 0.36%, concentration measurement XMeasuring9.83%, standard deviation 0.03%, relative error-1.9%.
The feasibility of the proposed method was examined at high temperature. Standard gas CO2The concentration of (2) was 5.02%. The temperature of the high-temperature tube furnace is set to be 500-900 ℃. The measurement method of the present invention was compared with a thermocouple every 100 ℃ interval, and the measurement results are shown in fig. 8. The concentration measurement results of the corresponding respective temperature measurement points are shown in fig. 9.
According to the embodiment, the measurement method provided by the invention can realize simultaneous measurement of the gas temperature and the gas concentration and can realize higher measurement sensitivity and precision under the condition that the selected spectral line meets the spectral line screening condition provided by the invention.
The single-line method provided by the invention can simultaneously measure the temperature and the concentration of the gas, reduces the number of required spectral lines, and has the advantages of high sensitivity, high precision and quick response time. Compared with the traditional Doppler broadening temperature measurement method, the method has wider application range and can be used for normal pressure or higher pressure. In addition, compared with the traditional method for measuring the temperature by a two-wire method, the problems of frequency crosstalk and time resolution do not need to be considered.
It should be understood that the above examples are only for clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And such obvious variations or modifications which fall within the spirit of the invention are intended to be covered by the scope of the present invention.
Claims (6)
1. An apparatus for simultaneously measuring gas temperature and concentration using a single spectral line, comprising: the laser comprises a function generator, a temperature current controller, a distributed feedback laser and a laser beam splitter in sequence; after a waveform function compiled by the function generator is regulated and controlled by the temperature and current controller, wavelength modulation is carried out on outgoing light by using a distributed feedback type laser, the modulated laser passes through a laser beam splitter, one path of the modulated laser is collimated by a collimating lens and then passes through a measuring area to obtain an absorption signal, and the absorption signal is transmitted into a signal acquisition system through a photoelectric detector; one path is firstly collimated by a collimating lens and then passes through corresponding wavelengthThe etalon is used for determining the relation between the optical frequency and the time, and the transmitted light intensity passes through the photoelectric detector to be accessed into the signal acquisition system for storage and algorithm processing; the measuring region uses a high-temperature tube furnace, the middle section of the tube furnace is a constant-temperature heating region, a three-section quartz glass gas absorption tank with a wedge surface is designed, a gas region is arranged in the middle section of the gas absorption tank and used for measuring temperature and concentration, and N is filled into two sides of the glass tube2Air isolation is performed.
2. A method for simultaneously measuring gas temperature and concentration using a single spectral line, comprising: the method firstly utilizes the line type of a peak value normalized second harmonic signal, wherein the line type is determined by temperature singleness, and the temperature of gas is extracted from the line type; and extracting concentration information by utilizing the second harmonic signal amplitude of the background-subtracted first harmonic normalization, wherein the signal amplitude is in direct proportion to the concentration, so that the temperature and the concentration of the gas are obtained simultaneously.
3. The method for simultaneously measuring the temperature and the concentration of a gas using a single spectral line as claimed in claim 2, comprising in particular the steps of:
step 1, processing the measured transmitted light intensity to obtain a measured peak value normalized second harmonic signal R2f/pAnd first harmonic normalized second harmonic signal R2f/1fAnd extracting R2f/1fThe initial values of the temperature and the concentration of the gas to be measured are respectively X0、T0Setting the initial value of n as 0;
step 2, for known XnChanging TnCombining the database to obtain a simulated peak normalized second harmonic signal, and fitting the measured peak normalized second harmonic signal by using a least square method to obtain Tn+1；
Step 3, for known Tn+1Changing XnCombining the database to obtain the simulated first harmonic normalized second harmonic signal and extracting different XnThe peak value is obtained by substituting p into the concentration-peak value relation of the simulation signal and obtaining the value corresponding to p by using an interpolation methodConcentration Xn+1；
And 4, judging whether the number n is large enough to meet a termination criterion:
wherein ξ is a predetermined threshold;
if yes, outputting Xn+1、Tn+1X of outputn+1、Tn+1Respectively measuring the concentration and temperature of the gas to be measured; if the termination criterion is not met, making n equal to n +1, returning to the step 2, and repeating the steps 2 to 4 until the termination criterion is met.
4. The method according to claim 3, wherein in step 1, the digital phase-locking and low-pass filtering processes are performed on the measured transmitted light intensity to obtain the X-component and the Y-component of each sub-harmonic signal of the background signal and the absorption signal, so as to extract the second harmonic signal with the background subtracted, and the expression is as follows:
in the formula, X2fAnd Y2fRespectively the X-component and the Y-component of the second harmonic of the absorption signal,andthe X component and the Y component of the second harmonic of the background signal, respectively, find S2fThe height p of the peak point, then the background-subtracted peak normalized second harmonic signal R2f/p＝S2f/p. Background-subtracted first harmonic normalized second harmonic signal R2f/1fThe expression is as follows:
in the formula, R1fAndthe first harmonic of the absorption signal and the background signal, respectively, is given by:
。
5. method for simultaneous measurement of gas temperature and concentration using a single spectral line as claimed in claim 3, characterized in that in step 2, the concentration X isnWhen known, assume the temperature TnThe spectral absorbance can be simulated in combination with the information provided by the database, and the expression is as follows:
α(v(t))＝Sj·φj(VC，VD，v(t))·P·Xi·L
in the formula, SjAnd phijRespectively the line intensity and the line type function of the jth spectral line, P is the total pressure of the gas, XiIs the mole fraction of the ith absorption gas, and L is the path length, from which the simulated transmitted light intensity can be obtained:
SIt＝I0·exp(-α)
in the formula I0The measured background light intensity is used for obtaining the simulated transmitted light intensity, then digital phase locking and low-pass filtering processing are carried out, and the simulated peak value normalization second harmonic signal is extracted.
6. The method for simultaneously measuring the temperature and the concentration of a gas by using a single spectral line as claimed in claim 3, wherein in the step 3, the concentration X is changed at a certain temperaturenFirst harmonic normalized second harmonic signal R combined with database simulation to subtract background2f/1fAnd extracting R2f/1fPeak value p of (a). The concentration is linear to the corresponding pAnd determining the gas concentration corresponding to the peak value by utilizing an interpolation method.
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| CN108107022A (en) * | 2018-01-18 | 2018-06-01 | 中国科学院西安光学精密机械研究所 | Non-contact type monitor and monitoring method for high-temperature gas dissolved in ocean |
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| CN110501092A (en) * | 2019-09-25 | 2019-11-26 | 华北电力大学（保定） | A kind of Brillouin light fiber sensor system temperature extraction method |
| CN112213283A (en) * | 2020-09-15 | 2021-01-12 | 江苏方天电力技术有限公司 | Gas concentration measuring method |
| CN112484905A (en) * | 2020-12-04 | 2021-03-12 | 中国航空工业集团公司北京长城计量测试技术研究所 | High-precision pressure optical measurement method in variable temperature environment |
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| CN107860726A (en) * | 2017-10-19 | 2018-03-30 | 江汉大学 | Quasi-distributed gas concentration detects second harmonic method for normalizing |
| CN107860726B (en) * | 2017-10-19 | 2020-04-17 | 江汉大学 | Quasi-distributed gas concentration detection second harmonic normalization method |
| CN108008146A (en) * | 2017-10-31 | 2018-05-08 | 天津工业大学 | A kind of method and apparatus for improving gas flow rate measurement accuracy |
| CN108107022A (en) * | 2018-01-18 | 2018-06-01 | 中国科学院西安光学精密机械研究所 | Non-contact type monitor and monitoring method for high-temperature gas dissolved in ocean |
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| CN109990843A (en) * | 2019-04-24 | 2019-07-09 | 南昌航空大学 | Monitor the method and device of vehicle flight speeds and local environment parameter |
| CN110501092A (en) * | 2019-09-25 | 2019-11-26 | 华北电力大学（保定） | A kind of Brillouin light fiber sensor system temperature extraction method |
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| CN112213283B (en) * | 2020-09-15 | 2023-12-15 | 江苏方天电力技术有限公司 | Gas concentration measuring method |
| CN112484905A (en) * | 2020-12-04 | 2021-03-12 | 中国航空工业集团公司北京长城计量测试技术研究所 | High-precision pressure optical measurement method in variable temperature environment |
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| CN112964662A (en) * | 2021-02-07 | 2021-06-15 | 中国科学院长春光学精密机械与物理研究所 | Method for measuring concentration and temperature of high-temperature fuel gas of aircraft engine |
| CN112964662B (en) * | 2021-02-07 | 2022-07-15 | 中国科学院长春光学精密机械与物理研究所 | Method for measuring concentration and temperature of high-temperature fuel gas of aircraft engine |
| CN115523958A (en) * | 2022-10-15 | 2022-12-27 | 浙江大学 | Gas temperature and concentration synchronous measurement method based on spectrum fast-slow separation principle |
| CN117740728A (en) * | 2023-12-15 | 2024-03-22 | 安徽皖仪科技股份有限公司 | TDLAS gas measurement method and system based on L-M nonlinear fitting |
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