CN105548072A - Method for simultaneous measurement of high-temperature gas two-dimensional transient temperature field and concentration field - Google Patents

Abstract

The invention discloses a method combining hyper-spectrum and wavelength modulation for simultaneous measurement of high-temperature gas two-dimensional transient temperature field and concentration field. The method includes: arranging a laser array in a to-be-measured high-temperature area, and conducting hyperspectral scanning on the to-be-measured area to obtain water vapor absorption spectral line information, and carrying out demodulation with a digital phase lock technology to obtain each harmonic signal, then conducting background deduction first harmonic normalization processing, extracting the maximum amplitude value of the signal to measure regional temperature field and water vapor concentration field, and during measuring, conducting grid discretization treatment on the to-be-measured area, arranging laser beam at each row and each column of the grid to conduct broad spectrum scanning on the characteristic spectral line of the to-be-measured gas under a wavelength modulation mode, and using intelligent optimization algorithm to realize inversion of the temperature field and gas concentration field. The measurement method provided by the invention combines hyper-spectrum and wavelength modulation spectroscopy technologies, and is especially suitable for monitoring of high-temperature gas two-dimensional temperature field and concentration field on harsh industrial sites.

Description

A kind of method simultaneously measuring high-temperature gas two dimension instantaneous temperature field and concentration field

Technical field

The present invention relates to a kind of method simultaneously measuring high-temperature gas two dimension instantaneous temperature field and concentration field in conjunction with ultraphotic spectrum and wavelength-modulated, belong to laser absorption spectrum field.

Background technology

In scientific research and engineer applied, the temperature of gas in some specific region, concentration parameter are the research course of work of some particular device and performance parameter, measurement and control state of matter and behavior, the important physical parameter improving energy utilization rate.Realize the in real time effectively monitoring of gas temperature field, concentration field the normal operation of the system of guarantee, environmental protection, energy-conservation and safe all significant.

At present, gas thermometry technology is mainly divided into two large classes: contact type measurement and non-contact measurement.Although contact Method of GAS Temperature Measurement is checked through engineering practice, there is credible result, with low cost and use the advantages such as simple in its scope of application, but because in contact type measurement process, physical probe can invade region to be measured, and then the temperature of measurand is had an impact, therefore, measurement result generally needs careful correction; And owing to being subject to the restriction making material, all cannot using in the occasion such as high temperature, high pressure, which has limited its scope of application; Moreover, because contact type measurement generally carries out the measurement of single point temperature, lack enough room and time resolution, and the description of numerous transient state temperature field needs multi-point non-contact measuring technique, the thermo parameters method of such as boiler of power plant inside, the thermo parameters method etc. of engine combustion indoor, the spot measurement that touch is abutted against in the distribution of these transient field can not complete.By contrast, development non-contact type temperature measurement method is needed.Contactless measurement overcomes the defect of contact measurement method, has surveying instrument without the need to invading region to be measured, temperature not by advantages such as extraneous factor interference.

Laser absorption spectroscopy is that gas sensing detects one of application aspect instrument the most powerful, utilize the feature of its high sensitivity, high spectral resolution, fast-response and Noninvasive, the gas detecting system based on technique is measured application aspect at the scene and is had significant advantage.Tradition based on direct absorption process surpasses spectroscopy measurement high-temperature gas two dimension instantaneous temperature field, the method of concentration field, the relative error between integration absorptivity calculated value and measured value is used to carry out iteration optimizing as objective function, be only applicable to gas concentration larger, absorptivity is higher, on-the-spot interference is less, can the situation of matching baseline, but in the industrial applications of many bad environments, as the particle in fluidized bed, pulverized coal particle in gasification furnace and flying dust, light scattering can be there is, cause nonabsorbable loss comparatively large and moment change, simultaneously owing to there is spectral line interference, matching baseline has difficulties.Above factor all causes the traditional ultraphotic spectral technology based on direct absorption process to be difficult to application.

Summary of the invention

Technical matters to be solved by this invention is to provide a kind of method simultaneously measuring high-temperature gas two dimension instantaneous temperature field and concentration field in conjunction with ultraphotic spectrum and wavelength-modulated, and this measuring method is specially adapted to the monitoring realizing high-temperature gas two-dimensional temperature field and concentration field in severe industry spot.

For solving the problems of the technologies described above, the technical solution adopted in the present invention is:

Measure a method for high-temperature gas two dimension instantaneous temperature field and concentration field simultaneously, comprise following operation steps:

Step one, the collection of measuring-signal:

First, the shape of 2 dimensional region to be measured is the rectangular area of L × D, according to shape and the size of 2 dimensional region to be measured, simultaneously in conjunction with the spatial resolution requirements of temperature, gas component concentrations, grid discretization is carried out to 2 dimensional region to be measured, be divided into the grid of M × N, an each grid respectively corresponding temperature and concentration treats measured value, and total treats that measured value number is 2 × M × N;

Secondly, according to the above-mentioned number treating measured value, from HITRAN database, the characteristic absorpting spectruming line of the corresponding gas of I bar is selected, wherein and extract each spectral line and to roll off the production line strength S (T in reference temperature ₀), transition low state energy level E ", the coefficient [a, b, c, d] of molecular partition function Q (T), the centre wavelength of r article of characteristic absorpting spectruming line is designated as λ _r; Wherein, r value is the integer in 1 ~ I;

Then, periodic low frequency sweep signal is produced by major clock control function generator, superpose periodic high-frequency driving signal simultaneously, be loaded on the Optical Maser System that is made up of Fourier mode-locked laser, with the output frequency of modulated laser, the laser beam that Optical Maser System produces is transmitted by single-mode fiber, exports the laser beam of M+N channel through multiplexer, wherein M bar laser beam realizes often advancing line scanning to region to be measured, and N bar laser beam often arranges region to be measured and scans;

Finally, use laser through the region to be measured purged with nitrogen, obtain M row background light intensity, be designated as I ₀i (), obtains N number of row background light intensity, is designated as I ₀j (), then the laser after modulation is passed high-temperature area to be measured, the laser after gas absorption detects corresponding M row transmitted light intensity by photodetector, is designated as I _ti (), N number of row transmitted light intensity, is designated as I _t(j), data collecting card gathers photodetector output signal, and experimental data is kept at computing machine to carry out post-processed; Wherein, i value is the integer in 1 ~ M, and j value is the integer in 1 ~ N;

Step 2, measuring-signal process, obtains measuring-signal peak value:

Through background light intensity, transmitted light intensity that digital servo-control, the process of low-pass filtering process are measured, and it is carried out to the first harmonic normalized of background correction, extract and measure the peak value of harmonic signal at r article of characteristic absorpting spectruming line place, be designated as p _{i, r}, p _{j, r};

Step 3, simulate signal process, obtains simulate signal peak value:

Suppose initial temperature field, region to be measured, distribution of concentration, calculate the transmitted light intensity of emulation, and the identical digital servo-control of optimum configurations, low-pass filtering process are carried out to emulation transmitted light intensity, obtain the background correction first harmonic normalization second harmonic signal emulated, extract the peak value of emulation harmonic signal at r article of characteristic absorpting spectruming line place, be designated as K _{i, r}, K _{j, r};

Step 4, solving of two dimension instantaneous temperature field, concentration field:

Use measuring-signal peak value p _{i, r}, p _{j, r}with simulate signal peak K _{i, r}, K _{j, r}between relative deviation carry out iteration optimizing as objective function, iteration is till objective function converges, and its objective function is as follows:

$D(X,T)=\underset{r=1}{\overset{I}{\Σ}}\underset{i=1}{\overset{M}{\Σ}}\frac{{(K_{i,r}-p_{i,r})}^2}{{K_{i,r}}^2}+\underset{r=1}{\overset{I}{\Σ}}\underset{j=1}{\overset{N}{\Σ}}\frac{{(K_{j,r}-p_{j,r})}^2}{{K_{j,r}}^2}---\left(1\right);$

In formula, X, T be iterative computation go out concentration field, temperature field, D (X, T) is practical measurement signals peak value p _{i, r}, p _{j, r}with simulate signal peak K _{i, r}, K _{j, r}between deviation.

Wherein, the concrete treatment step of described step 2 is:

First digital lock-in technique process background light intensity I is used ₀(i), I ₀the transmitted light intensity I of (j) and actual measurement _t(i), I _t(j), obtain signal i-th row, the x component of jth row place nth harmonic and y component expansion respectively, expansion is such as formula shown in (2), and wherein, n value is 1 or 2:

$\begin{array}{cc}{x}_{nf}^0\left(i\right)=I_0\left(i\right)\·cos(n\·2{\mathrm{\πf}}_{m}t)& y_{nf}^0\left(i\right)=I_0\left(i\right)\·sin(n\·2{\mathrm{\πf}}_{m}t)\end{array}$

$\begin{array}{cc}{x}_{nf}^0\left(j\right)=I_0\left(j\right)\·cos(n\·2{\mathrm{\πf}}_{m}t)& y_{nf}^0\left(j\right)=I_0\left(j\right)\·sin(n\·2{\mathrm{\πf}}_{m}t)\end{array}---\left(2\right);$

x _nf(i)＝I _t(i)·cos(n·2πf _mt)y _nf(i)＝I _t(i)·sin(n·2πf _mt)

x _nf(j)＝I _t(j)·cos(n·2πf _mt)y _nf(j)＝I _t(j)·sin(n·2πf _mt)

Secondly, the harmonic component of each signal is extracted through low-pass filter, shown in (3):

$\begin{array}{cc}{X}_{nf}^0\left(i\right)=lowpassfilter\left(x_{nf}^0\right(i\left)\right)& Y_{nf}^0\left(i\right)=lowpassfilter\left(y_{nf}^0\right(i\left)\right)\end{array}$

$\begin{array}{cc}{X}_{nf}^0\left(j\right)=lowpassfilter\left(x_{nf}^0\right(j\left)\right)& Y_{nf}^0\left(j\right)=lowpassfilter\left(y_{nf}^0\right(j\left)\right)\end{array}---\left(3\right);$

X _nf(i)＝lowpassfilter(x _nf(i))Y _nf(i)＝lowpassfilter(y _nf(i))

X _nf(j)＝lowpassfilter(x _nf(j))Y _nf(j)＝lowpassfilter(y _nf(j))

The amplitude of the i-th row obtained, jth row place background light intensity signal and transmitted light intensity signal is expressed as formula (4):

$R_{nf}^0\left(i\right)=\sqrt{{\left(X_{nf}^0\right(i\left)\right)}^2+{\left(Y_{nf}^0\right(i\left)\right)}^2}$

$\begin{array}{c}{R}_{nf}^0\left(j\right)=\sqrt{{\left(X_{nf}^0\right(j\left)\right)}^2+{\left(Y_{nf}^0\right(j\left)\right)}^2}\\ R_{nf}\left(j\right)=\sqrt{{\left(X_{nf}\right(i\left)\right)}^2+{\left(Y_{nf}\right(i\left)\right)}^2}\end{array}---\left(4\right);$

$R_{nf}\left(j\right)=\sqrt{{\left(X_{nf}\right(j\left)\right)}^2+{\left(Y_{nf}\right(j\left)\right)}^2}$

Finally, to the i-th row obtained and jth row harmonic signal, carry out background correction first harmonic normalized respectively, obtain:

$S_{2f/1f}\left(i\right)=\sqrt{{\[\left(\frac{X_{2f}\left(i\right)}{R_{1f}\left(i\right)}\right)-\left(\frac{X_{2f}^0\left(i\right)}{R_{1f}^0\left(i\right)}\right)\]}^2+{\[\left(\frac{Y_{2f}\left(i\right)}{R_{1f}\left(i\right)}\right)-\left(\frac{Y_{2f}^0\left(i\right)}{R_{1f}^0\left(i\right)}\right)\]}^2}---\left(5\right);$

$S_{2f/1f}\left(j\right)=\sqrt{{\[\left(\frac{X_{2f}\left(j\right)}{R_{1f}\left(j\right)}\right)-\left(\frac{X_{2f}^0\left(j\right)}{R_{1f}^0\left(j\right)}\right)\]}^2+\left(\frac{Y_{2f}\left(j\right)}{R_{1f}\left(j\right)}\right)-{\left(\frac{Y_{2f}^0\left(j\right)}{R_{1f}^0\left(j\right)}\right)}^2}---\left(6\right);$

Note S _2f/1f(i), S _2f/1fj () is respectively S at the signal at r article of characteristic absorpting spectruming line place _2f/1f(i, λ _r), S _2f/1f(j, λ _r), wherein, r value is the integer in 1 ~ I, then extracts the peak value of each bar spectral line background correction first harmonic normalization second harmonic signal respectively, is designated as p _{i, r}, P _{j, r}:

p _i，r＝max[S _2f/1f(i，λ _r)]

(7)。

p _j，r＝max[S _2f/1f(i，λ _r)]

Wherein, the concrete treatment step of described step 3 is:

First, what adopt each row, each row grid treats testing temperature, gas concentration discrete value, and in conjunction with Beer-Lambert law, for r article of laser, wherein, r value is the integer in 1 ~ I, and the gas absorbance obtained through region to be measured is:

$\mathrm{\α}(i,r)=P\·\mathrm{\Δ}d\underset{j=1}{\overset{N}{\Σ}}\underset{k=1}{\overset{I}{\Σ}}{X}_{i,j}S(T_{i,j},{\mathrm{\λ}}_r)\mathrm{\φ}({\mathrm{\λ}}_k-{\mathrm{\λ}}_r),i=1,2...M;---\left(8\right);$

$\mathrm{\α}(j,r)=P\·\mathrm{\Δ}l\underset{i=1}{\overset{M}{\Σ}}\underset{k=1}{\overset{I}{\Σ}}{X}_{i,j}S\left(T_{i,j},{\mathrm{\λ}}_r\right)\mathrm{\φ}\left({\mathrm{\λ}}_k-{\mathrm{\λ}}_r\right),j=1,2...N;---\left(9\right);$

In formula, α (i, r) is the absorbance of the i-th row under r article of spectral line, and α (j, r) is the absorbance of jth row under r article of spectral line, and P is gaseous tension, X _{i, j}be the water vapor concentration of component in the i-th row jth column unit lattice, S (T _ij, λ _i) be λ at wavelength by force for line _i, temperature is T _ijtime value, φ (λ _k-λ _r) be spectral line λ _rcorresponding linear function is in wavelength X _kthe value at place, select wherein a kind of from Gauss line style, Lorentz line style and Voigt line style according to the temperature in measurement environment, pressure condition, Δ d=D/M, Δ l=L/N are respectively line space and column pitch;

Secondly, for particular spectral lines λ _i, the function that the strong S of line (T) is temperature:

$S\left(T,{\mathrm{\λ}}_i\right)=S\left(T_0,{\mathrm{\λ}}_i\right)\frac{Q\left(T_0\right)}{Q\left(T\right)}\exp \[-\frac{{{\mathrm{hcE}}_i}^{\′\′}}{k}\left(\frac{1}{T}-\frac{1}{T_0}\right)\]\×\[\frac{1-\exp \left(-{\mathrm{hc}}^2/{\mathrm{kT\λ}}_i\right)}{1-\exp \left(-{\mathrm{hc}}^2/{\mathrm{kT}}_0{\mathrm{\λ}}_i\right)}\]---\left(10\right);$

Roll off the production line known reference temperature strong S (T ₀), low state energy level E ", Planck's constant h, light velocity c, Boltzmann constant k, corresponding grid temperature and molecular partition function substitute into formula (10) and obtain graticule intensity values S [T _{i, j}, λ _i], wherein molecular partition function Q (T) substitutes into formula (11) by the parameter checked in [a, b, c, d] and calculates:

Q(T)＝a+b·T+c·T ²+d·T ³(11)；

Then, in conjunction with gas absorbance and the emulation row transmitted light intensity obtaining each row without the background light intensity of actual measurement under acceptance condition and respectively arrange ^si _t(i), row transmitted light intensity ^si _t(j):

$\begin{array}{c}{I_s}_t\left(i\right)=I_0\left(i\right)\·\exp \[-\underset{r=1}{\overset{I}{\mathrm{\Σ}}}\mathrm{\α}\left(i,r\right)\]\\ =I_0\left(i\right)\·\exp \left\{-\underset{r=1}{\overset{I}{\mathrm{\Σ}}}\[P\·\mathrm{\Δ}d\underset{j=1}{\overset{N}{\mathrm{\Σ}}}\underset{k=1}{\overset{I}{\mathrm{\Σ}}}{X}_{i,j}S\left(T_{i,j},{\mathrm{\λ}}_r\right)\mathrm{\φ}\left({\mathrm{\λ}}_k-{\mathrm{\λ}}_r\right)\]\right\}\end{array}---\left(12\right);$

$\begin{array}{c}{I_s}_t\left(j\right)=I_0\left(j\right)\·\exp \[-\underset{r=1}{\overset{I}{\mathrm{\Σ}}}\mathrm{\α}\left(j,r\right)\]\\ =I_0\left(j\right)\·\exp \left\{-\underset{r=1}{\overset{I}{\mathrm{\Σ}}}\[P\·\mathrm{\Δ}l\underset{i=1}{\overset{M}{\mathrm{\Σ}}}\underset{k=1}{\overset{I}{\mathrm{\Σ}}}{X}_{i,j}S\left(T_{i,j},{\mathrm{\λ}}_r\right)\mathrm{\φ}\left({\mathrm{\λ}}_k-{\mathrm{\λ}}_r\right)\]\right\}\end{array}---\left(13\right);$

Re-use digital lock-in technique process emulation transmitted light intensity ^si _t(i), ^si _t(j), obtain this signal in the x component of the i-th row, jth row place nth harmonic and y component expansion, n value is 1 or 2:

^sx _nf(i)＝ ^sI _t(i)·cos(n·2πf _mt) ^sy _nf(i)＝ ^sI _t(i)·sin(n·2πf _mt)

(14)；

^sx _nf(j)＝ ^sI _t(j)·cos(n·2πf _mt) ^sy _nf(j)＝ ^sI _t(j)·sin(n·2πf _mt)

Then, the harmonic component of each signal is extracted through low-pass filter:

^sX _nf(i)＝lowpassfilter( ^sx _nf(i)) ^sY _nf(i)＝lowpassfilter( ^sy _nf(i))

(15)；

^sX _nf(j)＝lowpassfilter( ^sx _nf(j)) ^sY _nf(j)＝lowpassfilter( ^sy _nf(j))

The amplitude of the i-th row, jth row place emulation transmitted light intensity signal can be expressed as formula (16):

$\begin{array}{c}{R_s}_{nf}\left(i\right)=\sqrt{{\left({X_s}_{nf}\left(i\right)\right)}^2+{\left({Y_s}_{nf}\left(i\right)\right)}^2}\\ {R_s}_{nf}\left(j\right)=\sqrt{{\left({X_s}_{nf}\left(j\right)\right)}^2+{\left({Y_s}_{nf}\left(j\right)\right)}^2}\end{array}---\left(16\right);$

In formula, f _mmodulating frequency, ^sr _nf(i) be the i-th row transmission harmonic signal, ^sr _nfj () is jth row transmission harmonic signal;

Finally, carrying out background correction first harmonic normalized to emulating the harmonic signal obtained, obtaining following formula:

${S_s}_{2f/1f}\left(i\right)=\sqrt{{\[\left(\frac{{X_s}_{2f}\left(i\right)}{{R_s}_{1f}\left(i\right)}\right)-\left(\frac{X_{2f}^0\left(i\right)}{R_{1f}^0\left(i\right)}\right)\]}^2+{\[\left(\frac{{Y_s}_{2f}\left(i\right)}{{R_s}_{1f}\left(i\right)}\right)-\left(\frac{Y_{2f}^0\left(i\right)}{R_{1f}^0\left(i\right)}\right)\]}^2}---\left(17\right);$

${S_s}_{2f/1f}\left(j\right)=\sqrt{{\[\left(\frac{{X_s}_{2f}\left(j\right)}{{R_s}_{1f}\left(j\right)}\right)-\left(\frac{X_{2f}^0\left(j\right)}{R_{1f}^0\left(j\right)}\right)\]}^2+{\[\left(\frac{{Y_s}_{2f}\left(j\right)}{{R_s}_{1f}\left(j\right)}\right)-\left(\frac{Y_{2f}^0\left(j\right)}{R_{1f}^0\left(j\right)}\right)\]}^2}---\left(18\right);$

Note ^ss _2f/1f(i), ^ss _2f/1fj () signal at r article of characteristic absorpting spectruming line place is ^ss _2f/1f(i, λ _r), ^ss _2f/1f(j, λ _r), wherein, r value is the integer in 1 ~ I, then extracts the peak value of each bar spectral line background correction first harmonic normalization second harmonic signal respectively, is designated as K _{i, r}, K _{j, r}:

K _i，r＝max[ ^sS _2f/1f(i，λ _r)]

(19)。

K _j，r＝max[ ^sS _2f/1f(j，λ _r)]

Beneficial effect: relative to the measuring method of existing high-temperature gas two dimension instantaneous temperature field and concentration field, measuring method of the present invention combines ultraphotic spectrum and wavelength modulation spectrum technology, not only there is good noise suppression feature, to weak absorbing, there is higher sensitivity, and be more suitable for the measurement that the comparatively large and baseline of nonabsorbable loss is difficult to high temperature and high pressure gas two-dimensional temperature field under matching environment and concentration field; Therefore measuring method of the present invention is significant for the combustion diagnosis realizing accurately detecting thermal-flame in severe industry spot; In addition, the measurement mechanism used in measuring method of the present invention adopts Fourier mode-locked laser, and this laser instrument has the feature of high sweep velocity, wide range scanning and low noise, and it can realize the rapid scanning of wide spectral.

Accompanying drawing explanation

Fig. 1 is the measurement mechanism system architecture schematic diagram that measuring method of the present invention uses;

Fig. 2 is that in measuring method of the present invention, area grid to be measured divides and laser scans schematic diagram;

Fig. 3 is the derivation algorithm process flow diagram of temperature field and concentration field in measuring method of the present invention;

Fig. 4 is the design sketch of the region to be measured two-dimensional temperature field that measuring method of the present invention obtains;

Fig. 5 is the design sketch of the region to be measured two-dimensional concentration field that measuring method of the present invention obtains;

Wherein, framework 9 fixed by major clock 1, function generator 2, laser instrument 3, multiplexer 4, region to be measured collimating apparatus 5, photodetector 6, data collecting card 7, computing machine 8, collector lens.

Embodiment

According to following embodiment, the present invention may be better understood.But those skilled in the art will readily understand, the content described by embodiment only for illustration of the present invention, and should can not limit the present invention described in detail in claims yet.

As shown in Figures 1 to 3, the present invention measures the method for high-temperature gas two dimension instantaneous temperature field and concentration field simultaneously, comprises following concrete implementation step:

Step one, uses wavelength-modulated method, and detection obtains the signal that 2 dimensional region to be measured is often gone, often arranged:

First, according to shape (being assumed to be the rectangular area of L × D) and the size of 2 dimensional region to be measured, in conjunction with the spatial resolution requirements of temperature, gas component concentrations, grid discretization is carried out to 2 dimensional region to be measured, be divided into the grid of M × N, an each grid respectively corresponding temperature and concentration treats measured value, and total treats that measured value number is 2 × M × N, and according to stress and strain model mode, region to be measured is installed the Spatial infrastructure 9 being used for fixing ultraphotic spectrum Laser emission and acquisition elements;

Secondly, according to the above-mentioned number treating measured value, from HITRAN database, the characteristic absorpting spectruming line of the corresponding gas of I bar is selected, wherein and extract reference temperature and to roll off the production line strength S (T ₀), transition low state energy level E ", the coefficient [a, b, c, d] of molecular partition function Q (T), and the centre wavelength remembering r (r=1,2 ... I) bar characteristic absorpting spectruming line is λ _r;

Then, periodic low frequency sweep signal is produced by major clock 1 control function generator 2, superpose periodic high-frequency driving signal simultaneously, be loaded on the Optical Maser System that is made up of Fourier mode-locked laser (FDML) 3, with the output frequency of modulated laser 3, the laser beam that Optical Maser System produces is transmitted by single-mode fiber, the laser beam of M+N the channel for meeting requirement of experiment is exported through multiplexer 4, wherein M bar laser beam realizes often advancing line scanning to region to be measured, and N bar laser beam often arranges region to be measured and scans;

Finally, use laser through the region to be measured purged with nitrogen, obtain M row background light intensity, be designated as I ₀(i) (i=1,2 ... M), obtain N number of row background light intensity, be designated as I ₀(j) (j=1,2 ... N), then laser is passed high-temperature area to be measured, the laser after gas absorption detects corresponding M row transmitted light intensity by photodetector 6, is designated as I _t(i) (i=1,2 ... M), obtain N number of row transmitted light intensity, be designated as I _t(j) (j=1,2 ... N), data collecting card 7 pairs of photodetector 6 output signals gather, and experimental data are kept at computing machine 8 to carry out post-processed;

Step 2, measuring-signal process, obtains measuring-signal peak value:

Utilize the transmitted light intensity containing regional temperature field to be measured, concentration field information, and the low-pass filter using digital servo-control program and have an appropriate bandwidth is to extract the wavelength modulation signal at different harmonic wave place, avoid the needs that Fourier's analysis method characterizes Laser Modulation intensity, intactly have recorded all metrical informations.

First, digital lock-in technique process background light intensity I is used ₀(i), I ₀the transmitted light intensity I of (j) and actual measurement _t(i), I _tj (), obtains signal i-th row, the x component of jth row place n (n=1,2) subharmonic and y component expansion respectively:

$\begin{array}{cc}{x}_{nf}^0\left(i\right)=I_0\left(i\right)\·cos(n\·2{\mathrm{\πf}}_{m}t)& y_{nf}^0\left(i\right)=I_0\left(i\right)\·sin(n\·2{\mathrm{\πf}}_{m}t)\end{array}$

$\begin{array}{cc}{x}_{nf}^0\left(j\right)=I_0\left(j\right)\·cos(n\·2{\mathrm{\πf}}_{m}t)& y_{nf}^0\left(j\right)=I_0\left(j\right)\·sin(n\·2{\mathrm{\πf}}_{m}t)\end{array}---\left(1\right);$

x _nf(i)＝I _t(i)·cos(n·2πf _mt)y _nf(i)＝I _t(i)·sin(n·2πf _mt)

x _nf(j)＝I _t(j)·cos(n·2πf _mt)y _nf(j)＝I _t(j)·sin(n·2πf _mt)

Then, the harmonic component of each signal is extracted through low-pass filter:

$\begin{array}{cc}{X}_{nf}^0\left(i\right)=lowpassfilter\left(x_{nf}^0\right(i\left)\right)& Y_{nf}^0\left(i\right)=lowpassfilter\left(y_{nf}^0\right(i\left)\right)\end{array}$

$\begin{array}{cc}{X}_{nf}^0\left(j\right)=lowpassfilter\left(x_{nf}^0\right(j\left)\right)& Y_{nf}^0\left(j\right)=lowpassfilter\left(y_{nf}^0\right(j\left)\right)\end{array}---\left(2\right);$

X _nf(i)＝lowpassfilter(x _nf(i))Y _nf(i)＝lowpassfilter(y _nf(i))

X _nf(j)＝lowpassfilter(x _nf(j))Y _nf(j)＝lowpassfilter(y _nf(j))

So, the amplitude of the i-th row, jth row place background light intensity signal and transmitted light intensity signal can be expressed as:

$R_{nf}^0\left(i\right)=\sqrt{{\left(X_{nf}^0\right(i\left)\right)}^2+{\left(Y_{nf}^0\right(i\left)\right)}^2}$

$\begin{array}{c}{R}_{nf}^0\left(j\right)=\sqrt{{\left(X_{nf}^0\right(j\left)\right)}^2+{\left(Y_{nf}^0\right(j\left)\right)}^2}\\ R_{nf}\left(j\right)=\sqrt{{\left(X_{nf}\right(i\left)\right)}^2+{\left(Y_{nf}\right(i\left)\right)}^2}\end{array}---\left(3\right);$

$R_{nf}\left(j\right)=\sqrt{{\left(X_{nf}\right(j\left)\right)}^2+{\left(Y_{nf}\right(j\left)\right)}^2}$

Then, the optical transport change using normalized method can eliminate the scattering of laser beam to a certain extent, non-absorbing causes loss and cause due to the mechanical vibration of optical device, simultaneously, for the situation that background signal under wavelength-modulated method is larger relative to absorption signal, background correction signal can be subtracted to improve signal to noise ratio (S/N ratio), to reduce Concentration Testing lower limit on normalized basis, to the i-th row obtained and jth row harmonic signal, carry out background correction first harmonic normalized respectively, can obtain:

$S_{2f/1f}\left(i\right)=\sqrt{{\[\left(\frac{X_{2f}\left(i\right)}{R_{1f}\left(i\right)}\right)-\left(\frac{X_{2f}^0\left(i\right)}{R_{1f}^0\left(i\right)}\right)\]}^2+{\[\left(\frac{Y_{2f}\left(i\right)}{R_{1f}\left(i\right)}\right)-\left(\frac{Y_{2f}^0\left(i\right)}{R_{1f}^0\left(i\right)}\right)\]}^2}---\left(4\right);$

$S_{2f/1f}\left(j\right)=\sqrt{{\[\left(\frac{X_{2f}\left(j\right)}{R_{1f}\left(j\right)}\right)-\left(\frac{X_{2f}^0\left(j\right)}{R_{1f}^0\left(j\right)}\right)\]}^2+\left(\frac{Y_{2f}\left(j\right)}{R_{1f}\left(j\right)}\right)-{\left(\frac{Y_{2f}^0\left(j\right)}{R_{1f}^0\left(j\right)}\right)}^2}---\left(5\right);$

Finally, S is remembered _2f/1f(i), S _2f/1fj () is in r (r=1,2 ... I) signal at bar characteristic absorpting spectruming line place is S _2f/1f(i, λ _r), S _2f/1f(j, λ _r), then extract the peak value of each bar spectral line background correction first harmonic normalization second harmonic signal respectively, be designated as p _{i, r}, p _{i, r}:

p _i，r＝max[S _2f/1f(i，λ _r)]

(6)。

p _j，r＝max[S _2f/1f(i，λ _r)]

Step 3, simulate signal process, obtains simulate signal peak value:

When laser is through different grid, because the parameter such as the gas concentration in each grid, temperature is different, thus it is different to result in laser intensity decay, the S of what it detected comprise temperature and concentration information _2f/1fsignal is also different, and by supposing temperature, the gas concentration of each grid in region to be measured, in conjunction with known parameters, emulation obtains the harmonic signal of different rank:

What adopt each row, each row grid treats testing temperature, gas concentration discrete value, in conjunction with Beer-Lambert law, for r (r=1,2 ... I) bar laser, the gas absorbance obtained through region to be measured can be write as into:

$\mathrm{\α}(i,r)=P\·\mathrm{\Δ}d\underset{j=1}{\overset{N}{\Σ}}\underset{k=1}{\overset{I}{\Σ}}{X}_{i,j}S(T_{i,j},{\mathrm{\λ}}_r)\mathrm{\φ}({\mathrm{\λ}}_k-{\mathrm{\λ}}_r),i=1,2...M;---\left(7\right);$

$\mathrm{\α}(j,r)=P\·\mathrm{\Δ}l\underset{i=1}{\overset{M}{\Σ}}\underset{k=1}{\overset{I}{\Σ}}{X}_{i,j}S\left(T_{i,j},{\mathrm{\λ}}_r\right)\mathrm{\φ}\left({\mathrm{\λ}}_k-{\mathrm{\λ}}_r\right),j=1,2...N;---\left(8\right);$

In formula, α (i, r) is the absorbance of the i-th row under r article of spectral line, and α (j, r) is the absorbance of jth row under r article of spectral line, and P is gaseous tension (atm), X _{i, j}be the water vapor concentration of component in the i-th row jth column unit lattice, S (T _{i, j}, λ _i) be λ at wavelength by force for line _i, temperature is T _ijtime value (cm ^-2atm ^-1), φ (λ _k-λ _r) be spectral line λ _rcorresponding linear function is in wavelength X _kthe value (cm) at place, Δ d=D/M, Δ l=L/N are respectively line space and column pitch;

For particular spectral lines λ _i, the function that the strong S of line (T) is temperature, can be determined by following formula:

$S\left(T,{\mathrm{\λ}}_i\right)=S\left(T_0,{\mathrm{\λ}}_i\right)\frac{Q\left(T_0\right)}{Q\left(T\right)}\exp \[-\frac{{{\mathrm{hcE}}_i}^{\′\′}}{k}\left(\frac{1}{T}-\frac{1}{T_0}\right)\]\×\[\frac{1-\exp \left(-{\mathrm{hc}}^2/{\mathrm{kT\λ}}_i\right)}{1-\exp \left(-{\mathrm{hc}}^2/{\mathrm{kT}}_0{\mathrm{\λ}}_i\right)}\]---\left(9\right);$

To roll off the production line strong S (T with reference to temperature ₀), low state energy level E ", Planck's constant h, light velocity c, Boltzmann constant k, corresponding grid temperature, molecular partition function etc. substitute into above formula (9) and can obtain graticule intensity values S [T _{i, j}, λ _i], for the calculating of molecular partition function Q (T), the parameter checked in step one [a, b, c, d] is substituted into following formula:

Q(T)＝a+b·T+c·T ²+d·T ³(10)；

For linear function φ (λ-λ _i), need select from three kinds of line styles (Gauss line style, Lorentz line style, Voigt line style) according to the temperature in measurement environment, pressure condition, will determine that expression formula substitutes into above formula (7), (8) calculate;

In conjunction with gas absorbance and the emulation row transmitted light intensity obtaining each row without the background light intensity of actual measurement under acceptance condition and respectively arrange ^si _t(i), row transmitted light intensity ^si _t(j):

$\begin{array}{c}{I_s}_t\left(i\right)=I_0\left(i\right)\·\exp \[-\underset{r=1}{\overset{I}{\mathrm{\Σ}}}\mathrm{\α}\left(i,r\right)\]\\ =I_0\left(i\right)\·\exp \left\{-\underset{r=1}{\overset{I}{\mathrm{\Σ}}}\[P\·\mathrm{\Δ}d\underset{j=1}{\overset{N}{\mathrm{\Σ}}}\underset{k=1}{\overset{I}{\mathrm{\Σ}}}{X}_{i,j}S\left(T_{i,j},{\mathrm{\λ}}_r\right)\mathrm{\φ}\left({\mathrm{\λ}}_k-{\mathrm{\λ}}_r\right)\]\right\}\end{array}---\left(11\right);$

$\begin{array}{c}{I_s}_t\left(j\right)=I_0\left(j\right)\·\exp \[-\underset{r=1}{\overset{I}{\mathrm{\Σ}}}\mathrm{\α}\left(j,r\right)\]\\ =I_0\left(j\right)\·\exp \left\{-\underset{r=1}{\overset{I}{\mathrm{\Σ}}}\[P\·\mathrm{\Δ}l\underset{i=1}{\overset{M}{\mathrm{\Σ}}}\underset{k=1}{\overset{I}{\mathrm{\Σ}}}{X}_{i,j}S\left(T_{i,j},{\mathrm{\λ}}_r\right)\mathrm{\φ}\left({\mathrm{\λ}}_k-{\mathrm{\λ}}_r\right)\]\right\}\end{array}---\left(12\right);$

Use digital lock-in technique process emulation transmitted light intensity ^si _t(i), ^si _tj (), obtains this signal in the x component of the i-th row, jth row place n (n=1,2) subharmonic and y component expansion:

^sx _nf(i)＝ ^sI _t(i)·cos(n·2πf _mt) ^sy _nf(i)＝ ^sI _t(i)·sin(n·2πf _mt)

(13)；

^sx _nf(j)＝ ^sI _t(j)·cos(n·2πf _mt) ^sy _nf(j)＝ ^sI _t(j)·sin(n·2πf _mt)

Then, the harmonic component of each signal is extracted through low-pass filter:

^sX _nf(i)＝lowpassfilter( ^sx _nf(i)) ^sY _nf(i)＝lowpassfilter( ^sy _nf(i))

(14)；

^sX _nf(j)＝lowpassfilter( ^sx _nf(j)) ^sY _nf(j)＝lowpassfilter( ^sy _nf(j))

The amplitude of the i-th row, jth row place emulation transmitted light intensity signal can be expressed as:

$\begin{array}{c}{R_s}_{nf}\left(i\right)=\sqrt{{\left({X_s}_{nf}\left(i\right)\right)}^2+{\left({Y_s}_{nf}\left(i\right)\right)}^2}\\ {R_s}_{nf}\left(j\right)=\sqrt{{\left({X_s}_{nf}\left(j\right)\right)}^2+{\left({Y_s}_{nf}\left(j\right)\right)}^2}\end{array}---\left(15\right);$

In formula, f _mmodulating frequency, ^sr _nf(i) be the i-th row transmission harmonic signal, ^sr _nfj () is jth row transmission harmonic signal;

In order to eliminate light-intensity variation impact, carrying out background correction first harmonic normalized to emulating the harmonic signal obtained, obtaining formula (16), (17):

${S_s}_{2f/1f}\left(i\right)=\sqrt{{\[\left(\frac{{X_s}_{2f}\left(i\right)}{{R_s}_{1f}\left(i\right)}\right)-\left(\frac{X_{2f}^0\left(i\right)}{R_{1f}^0\left(i\right)}\right)\]}^2+{\[\left(\frac{{Y_s}_{2f}\left(i\right)}{{R_s}_{1f}\left(i\right)}\right)-\left(\frac{Y_{2f}^0\left(i\right)}{R_{1f}^0\left(i\right)}\right)\]}^2}---\left(16\right);$

${S_s}_{2f/1f}\left(j\right)=\sqrt{{\[\left(\frac{{X_s}_{2f}\left(j\right)}{{R_s}_{1f}\left(j\right)}\right)-\left(\frac{X_{2f}^0\left(j\right)}{R_{1f}^0\left(j\right)}\right)\]}^2+{\[\left(\frac{{Y_s}_{2f}\left(j\right)}{{R_s}_{1f}\left(j\right)}\right)-\left(\frac{Y_{2f}^0\left(j\right)}{R_{1f}^0\left(j\right)}\right)\]}^2}---\left(17\right);$

Note ^ss _2f/1f(i), ^ss _2f/1fj () is in r (r=1,2 ... I) signal at bar characteristic absorpting spectruming line place is ^ss _2f/1f(i, λ _r), ^ss _2f/1f(j, λ _r), then extract the peak value of each bar spectral line background correction first harmonic normalization second harmonic signal respectively, be designated as K _{i, r}, K _{j, r}:

K _i，r＝max[ ^sS _2f/1f(i，λr)]

(18)；

K _j，r＝max[ ^sS _2f/1f(j，λ _r)]

Step 4, solving of two dimension instantaneous temperature field, concentration field:

In Wavelength modulation spectroscopy, the height correlation of regional temperature to be measured, concentration information and harmonic signal, uses measuring-signal peak value p _{i, r}, p _{j, r}with simulate signal peak K _{i, r}, K _{j, r}between relative deviation carry out iteration optimizing as objective function, iteration (is less than setting accuracy value, as 10 till objective function converges ^-5), its objective function is as follows:

$D\left(X,T\right)=\underset{r=1}{\overset{I}{\mathrm{\Σ}}}\underset{i=1}{\overset{M}{\mathrm{\Σ}}}\frac{{\left(K_{i,r}-p_{i,r}\right)}^2}{{K_{i,r}}^2}+\underset{r=1}{\overset{I}{\mathrm{\Σ}}}\underset{j=1}{\overset{N}{\mathrm{\Σ}}}\frac{{\left(K_{j,r}-p_{j,r}\right)}^2}{{K_{j,r}}^2}---\left(19\right);$

In formula, X, T be iterative computation go out concentration field, temperature field, D (X, T) is measuring-signal peak value p _{i, r}, p _{i, r}with simulate signal peak K _{i, r}, K _{j, r}between deviation.

Fig. 4 ~ Fig. 5 is respectively the design sketch that measuring method of the present invention is rebuild the temperature field of standard flat flame burner and water vapor concentration field.

As can be seen from Fig. 4 ~ Fig. 5, measuring method of the present invention is by composing and wavelength modulation spectrum technology in conjunction with ultraphotic, antijamming capability is good, not only to noise, there is better inhibition, and to weak absorbing, also there is higher sensitivity, be particularly useful for the measurement that the comparatively large and baseline of nonabsorbable loss is difficult to high-temperature gas two-dimensional temperature field under matching environment and concentration field.

Claims (3)

1. measure a method for high-temperature gas two dimension instantaneous temperature field and concentration field simultaneously, it is characterized in that, comprise following operation steps:

Step one, the collection of measuring-signal:

First, the shape of 2 dimensional region to be measured is the rectangular area of L × D, according to shape and the size of 2 dimensional region to be measured, simultaneously in conjunction with the spatial resolution requirements of temperature, gas component concentrations, grid discretization is carried out to 2 dimensional region to be measured, be divided into the grid of M × N, an each grid respectively corresponding temperature and concentration treats measured value, and total treats that measured value number is 2 × M × N;

Secondly, according to the above-mentioned number treating measured value, from HITRAN database, the characteristic absorpting spectruming line of the corresponding gas of I bar is selected, wherein and extract each spectral line and to roll off the production line strength S (T in reference temperature ₀), transition low state energy level E ", the coefficient [a, b, c, d] of molecular partition function Q (T), the centre wavelength of r article of characteristic absorpting spectruming line is designated as λ _r; Wherein, r value is the integer in 1 ~ I;

Then, periodic low frequency sweep signal is produced by major clock control function generator, superpose periodic high-frequency driving signal simultaneously, be loaded on the Optical Maser System that is made up of Fourier mode-locked laser, with the output frequency of modulated laser, the laser beam that Optical Maser System produces is transmitted by single-mode fiber, exports the laser beam of M+N channel through multiplexer, wherein M bar laser beam realizes often advancing line scanning to region to be measured, and N bar laser beam often arranges region to be measured and scans;

Finally, use laser through the region to be measured purged with nitrogen, obtain M row background light intensity, be designated as I ₀i (), obtains N number of row background light intensity, is designated as I ₀j (), then the laser after modulation is passed high-temperature area to be measured, the laser after gas absorption detects corresponding M row transmitted light intensity by photodetector, is designated as I _ti (), N number of row transmitted light intensity, is designated as I _t(j), data collecting card gathers photodetector output signal, and experimental data is kept at computing machine to carry out post-processed; Wherein, i value is the integer in 1 ~ M, and i value is the integer in 1 ~ N;

Step 2, measuring-signal process, obtains measuring-signal peak value:

Through background light intensity, transmitted light intensity that digital servo-control, the process of low-pass filtering process are measured, and it is carried out to the first harmonic normalized of background correction, extract and measure the peak value of harmonic signal at r article of characteristic absorpting spectruming line place, be designated as p _{i, r}, p _{j, r};

Step 3, simulate signal process, obtains simulate signal peak value:

Suppose initial temperature field, region to be measured, distribution of concentration, calculate the transmitted light intensity of emulation, and the identical digital servo-control of optimum configurations, low-pass filtering process are carried out to emulation transmitted light intensity, obtain emulate background correction after through the normalized second harmonic signal of first harmonic, extract the peak value of emulation harmonic signal at r article of characteristic absorpting spectruming line place, be designated as K _{i, r}, K _{j, r};

Step 4, solving of two dimension instantaneous temperature field, concentration field:

Use measuring-signal peak value p _{i, r}, p _{j, r}with simulate signal peak K _{i, r}, K _{j, r}between relative deviation carry out iteration optimizing as objective function, iteration is till objective function converges, and its objective function is as follows:

$D\left(X,T\right)=\underset{r=1}{\overset{I}{\Σ}}\underset{i=1}{\overset{M}{\Σ}}\frac{{\left(K_{i,r}-p_{i,r}\right)}^2}{{K_{i,r}}^2}+\underset{r=1}{\overset{I}{\Σ}}\underset{j=1}{\overset{N}{\Σ}}\frac{{\left(K_{j,r}-p_{j,r}\right)}^2}{{K_{j,r}}^2}---\left(1\right);$

In formula, X, T be iterative computation go out concentration field, temperature field, D (X, T) is practical measurement signals peak value p _{i, r}, p _{j, r}with simulate signal peak K _{i, r}, K _{j, r}between deviation.

2. measure the method for high-temperature gas two dimension instantaneous temperature field and concentration field according to claim 1, it is characterized in that, the concrete treatment step of described step 2 is simultaneously:

First digital lock-in technique process background light intensity I is used ₀(i), I ₀the transmitted light intensity I of (j) and actual measurement _t(i), I _t(j), obtain signal i-th row, the x component of jth row place nth harmonic and y component expansion respectively, expansion is such as formula shown in (2), and wherein, n value is 1 or 2:

$\begin{array}{cc}{x}_{nf}^0\left(i\right)=I_0\left(i\right)\·\cos \left(n\·2{\mathrm{\πf}}_{m}t\right)& y_{nf}^0\left(i\right)=I_0\left(i\right)\·\sin \left(n\·2{\mathrm{\πf}}_{m}t\right)\\ x_{nf}^0\left(j\right)=I_0\left(j\right)\·\cos \left(n\·2{\mathrm{\πf}}_{m}t\right)& y_{nf}^0\left(j\right)=I_0\left(j\right)\·\sin \left(n\·2{\mathrm{\πf}}_{m}t\right)\\ x_{nf}\left(i\right)=I_t\left(i\right)\·\cos \left(n\·2{\mathrm{\πf}}_{m}t\right)& y_{nf}\left(i\right)=I_t\left(i\right)\·\sin \left(n\·2{\mathrm{\πf}}_{m}t\right)\\ x_{nf}\left(j\right)=I_t\left(j\right)\·\cos \left(n\·2{\mathrm{\πf}}_{m}t\right)& y_{nf}\left(j\right)=I_t\left(j\right)\·\sin \left(n\·2{\mathrm{\πf}}_{m}t\right)\end{array}---\left(2\right);$

Secondly, the harmonic component of each signal is extracted through low-pass filter, shown in (3):

$\begin{array}{cc}{X}_{nf}^0\left(i\right)=lowpassfilter\left(x_{nf}^0\left(i\right)\right)& Y_{nf}^0\left(i\right)=lowpassfilter\left(y_{nf}^0\left(i\right)\right)\\ X_{nf}^0\left(j\right)=lowpassfilter\left(x_{nf}^0\left(j\right)\right)& Y_{nf}^0\left(j\right)=lowpassfilter\left(y_{nf}^0\left(j\right)\right)\\ X_{nf}\left(i\right)=lowpassfilter\left(x_{nf}\left(i\right)\right)& Y_{nf}\left(i\right)=lowpassfilter\left(y_{nf}\left(i\right)\right)\\ X_{nf}\left(j\right)=lowpassfilter\left(x_{nf}\left(j\right)\right)& Y_{nf}\left(j\right)=lowpassfilter\left(y_{nf}\left(j\right)\right)\end{array}---\left(3\right);$

The amplitude of the i-th row obtained, jth row place background light intensity signal and transmitted light intensity signal, can be expressed as formula (4):

$\begin{array}{c}{R}_{nf}^0\left(i\right)=\sqrt{{\left(X_{nf}^0\left(i\right)\right)}^2+{\left(Y_{nf}^0\left(i\right)\right)}^2}\\ R_{nf}^0\left(j\right)=\sqrt{{\left(X_{nf}^0\left(j\right)\right)}^2+{\left(Y_{nf}^0\left(j\right)\right)}^2}\\ R_{nf}\left(i\right)=\sqrt{{\left(X_{nf}\left(i\right)\right)}^2+{\left(Y_{nf}\left(i\right)\right)}^2}\\ R_{nf}\left(j\right)=\sqrt{{\left(X_{nf}\left(j\right)\right)}^2+{\left(Y_{nf}\left(j\right)\right)}^2}\end{array}---\left(4\right);$

Finally, to the i-th row obtained and jth row harmonic signal, carry out the first harmonic normalized of background correction respectively, obtain:

$S_{2f/1f}\left(i\right)=\sqrt{{\[\left(\frac{X_{2f}\left(i\right)}{R_{1f}\left(i\right)}\right)-\left(\frac{X_{2f}^0\left(i\right)}{R_{1f}^0\left(i\right)}\right)\]}^2+{\[\left(\frac{Y_{2f}\left(i\right)}{R_{1f}\left(i\right)}\right)-\left(\frac{Y_{2f}^0\left(i\right)}{R_{1f}^0\left(i\right)}\right)\]}^2}---\left(5\right);$

$S_{2f/1f}\left(j\right)=\sqrt{{\[\left(\frac{X_{2f}\left(j\right)}{R_{1f}\left(j\right)}\right)-\left(\frac{X_{2f}^0\left(j\right)}{R_{1f}^0\left(j\right)}\right)\]}^2+{\[\left(\frac{Y_{2f}\left(j\right)}{R_{1f}\left(j\right)}\right)-\left(\frac{Y_{2f}^0\left(j\right)}{R_{1f}^0\left(j\right)}\right)\]}^2}---\left(6\right);$

Note S _2f/1f(i), S _2f/1fj () is respectively S at the signal at r article of characteristic absorpting spectruming line place _2f/1f(i, λ _r), S _2f/1f(j, λ _r), wherein, r value is the integer in 1 ~ I, then extracts the peak value of the normalized second harmonic signal of first harmonic of each bar spectral line background correction respectively, is designated as p _{i, r}, p _{j, r}:

$\begin{array}{c}{p}_{i,r}=\max \[S_{2f/1f}\left(i,{\mathrm{\λ}}_r\right)\]\\ p_{j,r}=\max \[S_{2f/1f}\left(i,{\mathrm{\λ}}_r\right)\]\end{array}---\left(7\right).$

3. measure the method for high-temperature gas two dimension instantaneous temperature field and concentration field according to claim 1, it is characterized in that, the concrete treatment step of described step 3 is simultaneously:

First, what adopt each row, each row grid treats testing temperature, gas concentration discrete value, and in conjunction with Beer-Lambert law, for r article of laser, wherein, r value is the integer in 1 ~ I, and the gas absorbance obtained through region to be measured is:

$\mathrm{\α}(i,r)=P\·\mathrm{\Δ}d\underset{j=1}{\overset{N}{\Σ}}\underset{k=1}{\overset{I}{\Σ}}{X}_{i,j}S(T_{i,j},{\mathrm{\λ}}_r)\mathrm{\φ}({\mathrm{\λ}}_k-{\mathrm{\λ}}_r),i=1,2...M;---\left(8\right);$

$\mathrm{\α}(j,r)=P\·\mathrm{\Δ}l\underset{i=1}{\overset{M}{\Σ}}\underset{k=1}{\overset{I}{\Σ}}{X}_{i,j}S(T_{i,j},{\mathrm{\λ}}_r)\mathrm{\φ}({\mathrm{\λ}}_k-{\mathrm{\λ}}_r),j=1,2...N;---\left(9\right);$

In formula, α (i, r) is the absorbance of the i-th row under r article of spectral line, and α (j, r) is the absorbance of jth row under r article of spectral line, and P is gaseous tension, X _{i, j}be the water vapor concentration of component in the i-th row jth column unit lattice, S (T _ij, λ _i) be λ at wavelength by force for line _i, temperature is T _ijtime value, φ (λ _k-λ _r) be spectral line λ _rcorresponding linear function is in wavelength X _kthe value at place, select wherein a kind of from Gauss line style, Lorentz line style and Voigt line style according to the temperature in measurement environment, pressure condition, Δ d=D/M, Δ l=L/N are respectively line space and column pitch;

Secondly, obtain in conjunction with gas absorbance and the background light intensity without actual measurement under acceptance condition the emulation row transmitted light intensity that each row respectively arranges ^si _t(i), row transmitted light intensity ^si _t(j):

$\begin{array}{c}{I_s}_t\left(i\right)=I_0\left(i\right)\·\exp \[-\underset{r=1}{\overset{I}{\Σ}}\mathrm{\α}\left(i,r\right)\]\\ =I_0\left(i\right)\·\exp \left\{-\underset{r=1}{\overset{I}{\Σ}}\[P\·\mathrm{\Δ}d\underset{j=1}{\overset{N}{\Σ}}\underset{k=1}{\overset{I}{\Σ}}{X}_{i,j}S\left(T_{i,j},{\mathrm{\λ}}_r\right)\mathrm{\φ}\left({\mathrm{\λ}}_k-{\mathrm{\λ}}_r\right)\]\right\}\end{array}---\left(10\right);$

$\begin{array}{c}{I_s}_t\left(j\right)=I_0\left(j\right)\·\exp \[-\underset{r=1}{\overset{I}{\Σ}}\mathrm{\α}\left(j,r\right)\]\\ =I_0\left(j\right)\·\exp \left\{-\underset{r=1}{\overset{I}{\Σ}}\[P\·\mathrm{\Δ}l\underset{i=1}{\overset{M}{\Σ}}\underset{k=1}{\overset{I}{\Σ}}{X}_{i,j}S\left(T_{i,j},{\mathrm{\λ}}_r\right)\mathrm{\φ}\left({\mathrm{\λ}}_k-{\mathrm{\λ}}_r\right)\]\right\}\end{array}---\left(11\right);$

Re-use digital lock-in technique process emulation transmitted light intensity ^si _t(i), ^si _t(j), obtain this signal in the x component of the i-th row, jth row place nth harmonic and y component expansion, n value is 1 or 2:

$\begin{array}{cc}{x_s}_{nf}\left(i\right)={I_s}_t\left(i\right)\·\cos \left(n\·2{\mathrm{\πf}}_{m}t\right)& {y_s}_{nf}\left(i\right)={I_s}_t\left(i\right)\·\sin \left(n\·2{\mathrm{\πf}}_{m}t\right)\\ {x_s}_{nf}\left(j\right)={I_s}_t\left(j\right)\·\cos \left(n\·2{\mathrm{\πf}}_{m}t\right)& {y_s}_{nf}\left(j\right)={I_s}_t\left(j\right)\·\sin \left(n\·2{\mathrm{\πf}}_{m}t\right)\end{array}---\left(12\right);$

Then, the harmonic component of each signal is extracted through low-pass filter:

$\begin{array}{cc}{X_s}_{nf}\left(i\right)=lowpassfilter\left({x_s}_{nf}\left(i\right)\right)& {Y_s}_{nf}\left(i\right)=lowpassfilter\left({y_s}_{nf}\left(i\right)\right)\\ {X_s}_{nf}\left(j\right)=lowpassfilter\left({x_s}_{nf}\left(j\right)\right)& {Y_s}_{nf}\left(j\right)=lowpassfilter\left({y_s}_{nf}\left(j\right)\right)\end{array}---\left(13\right);$

The amplitude of the i-th row, jth row place emulation transmitted light intensity signal can be expressed as formula (14):

$\begin{array}{c}{R_s}_{nf}\left(i\right)=\sqrt{{\left({X_s}_{nf}\left(i\right)\right)}^2+{\left({Y_s}_{nf}\left(i\right)\right)}^2}\\ {R_s}_{nf}\left(j\right)=\sqrt{{\left({X_s}_{nf}\left(j\right)\right)}^2+{\left({Y_s}_{nf}\left(j\right)\right)}^2}\end{array}---\left(14\right);$

In formula, f _mmodulating frequency, ^sr _nf(i) be the i-th row transmission harmonic signal, ^sr _nfj () is jth row transmission harmonic signal;

Finally, to the first harmonic normalized emulating the harmonic signal that obtains and carry out background correction, following formula is obtained:

${S_s}_{2f/1f}\left(i\right)=\sqrt{{\[\left(\frac{{X_s}_{2f}\left(i\right)}{{R_s}_{1f}\left(i\right)}\right)-\left(\frac{X_{2f}^0\left(i\right)}{R_{1f}^0\left(i\right)}\right)\]}^2+{\[\left(\frac{{Y_s}_{2f}\left(i\right)}{{R_s}_{1f}\left(i\right)}\right)-\left(\frac{Y_{2f}^0\left(i\right)}{R_{1f}^0\left(i\right)}\right)\]}^2}---\left(15\right);$

${S_s}_{2f/1f}\left(j\right)=\sqrt{{\[\left(\frac{{X_s}_{2f}\left(j\right)}{{R_s}_{1f}\left(j\right)}\right)-\left(\frac{X_{2f}^0\left(j\right)}{R_{1f}^0\left(j\right)}\right)\]}^2+{\[\left(\frac{{Y_s}_{2f}\left(j\right)}{{R_s}_{1f}\left(j\right)}\right)-\left(\frac{Y_{2f}^0\left(j\right)}{R_{1f}^0\left(j\right)}\right)\]}^2}---\left(16\right);$

Note ^ss _2f/1f(i), ^ss _2f/1fj () signal at r article of characteristic absorpting spectruming line place is ^ss _2f/1f(i, λ _r), ^ss _2f/1f(j, λ _r), wherein, r value is the integer in 1 ~ I, then extracts the peak value of the first harmonic normalization second harmonic signal of each bar spectral line background correction respectively, is designated as K _{i, r}, K _{j, r}:

$\begin{array}{c}{K}_{i,r}=\max \[{S_s}_{2f/1f}\left(i,{\mathrm{\λ}}_r\right)\]\\ K_{j,r}=\max \[{S_s}_{2f/1f}\left(j,{\mathrm{\λ}}_r\right)\]\end{array}---\left(17\right).$