CN103344601A - Translucent material absorption coefficient measuring method based on fourier transform infrared spectrum analyzer - Google Patents

Abstract

A translucent material absorption coefficient measuring method based on a fourier transform infrared spectrum analyzer relates to the field of measuring the material thermophysical property, and particularly relates to a translucent material absorption coefficient measuring method. The translucent material absorption coefficient measuring method aims at solving the problems that the existing translucent material absorption coefficient measuring method is complicated to operate and slow in measuring speed. The translucent material absorption coefficient measuring method is realized on the basis of the fourier transform infrared spectrum analyzer. The spectral absorption coefficient ka <gama> of a test piece material can be obtained by calculating according to the beer law by utilizing the spectrum transmittance t<gama> of a test piece and the reflectivity p<gama> of the test piece material, the Planck mean absorption coefficient kap and the rosseland mean absorption coefficient kaR can be obtained as the measurement results of the translucent material absorption coefficient to complete the measurement of the fourier-transform-infrared-spectrum-analyzer-based translucent material absorption coefficient by integrating a whole spectrum by utilizing the spectrum absorption coefficient ka<gama> of the test piece material. The translucent material absorption coefficient measuring method is applicable to measurement of the translucent material absorption coefficient.

Description

Trnaslucent materials absorption coefficient measuring method based on the FFIR analyser

Technical field

The present invention relates to material thermophysical property measurement field, be specifically related to a kind of trnaslucent materials absorption coefficient measuring method.

Background technology

Absorption coefficient is to characterize absorbing medium inside along the physical quantity of journey to emittance absorptive power, be one at optics and the extremely important physical parameter of infrared radiation transmission field.

The measurement of absorption coefficient relates to a plurality of fields such as Aero-Space, military affairs, the energy, chemical industry, biologic medical and atmospheric science, its typical case uses and to comprise: aerospacecraft optical window optimal design, translucent Thermal Control Coating Material thickness detect, the fusing of optical crystal growth, reactor uranium fuel and solidify, in the high temperature heat storage system phase-change material fusing and solidify and biological tissue in the research of radiation delivery problem etc., but still there is complicated operation in existing trnaslucent materials absorption coefficient measuring method, the problem that measuring speed is slow.

Summary of the invention

There is complicated operation in the present invention in order to solve existing trnaslucent materials absorption coefficient measuring method, and the problem that measuring speed is slow has proposed a kind of trnaslucent materials absorption coefficient measuring method based on the FFIR analyser.

Trnaslucent materials absorption coefficient measuring method based on the FFIR analyser of the present invention, it is based on, and the FFIR analyser realizes; It is based on the realization of FFIR analyser; This spectroanalysis instrument comprises: power supply, interferometer, light source, measuring chamber, total reflective mirror and detector; Interferometer comprises a total reflective mirror, No. two total reflective mirrors, half-reflecting half mirror, lens and No. three total reflective mirrors; The beam emissions that light source sends is to the half-reflecting half mirror of interferometer, folded light beam behind half-reflecting half mirror is returned half-reflecting half mirror through a total reflective mirror back reflection, after the half-reflecting half mirror transmission, be incident to lens, transmitted light beam behind half-reflecting half mirror returns half-reflecting half mirror through No. two total reflective mirror back reflections, is incident to lens after the half-reflection and half-transmission mirror reflection; Light beam after the lens transmission is incident to measuring chamber through No. three total reflective mirrors, and the light beam after measuring chamber is measured is incident to the photosurface of detector through total reflective mirror;

Power supply is used to interferometer, light source and detector power supply;

Measuring chamber comprises the test specimen frame, and the test specimen frame is used for fixedly test specimen; The center of described test specimen and the optical axis of light beam and being centered close on the straight line of total reflective mirror behind No. three total reflective mirrors, and light beam is vertical with the test specimen surface after No. three total reflective mirror emissions;

It is characterized in that the concrete steps of this method are:

Step 1, open the power supply of FFIR analyser, and preheating n minute, n 〉=20, preheating finishes the emittance I that a test specimen is gathered in the back _λ

Step 2, test specimen is put into measuring chamber, be fixed on the test specimen frame, to the emittance I of transmission _{λ, L}Gather, obtain the spectral-transmission favtor τ of this test specimen _λ

The spectral transmittance τ of the test specimen that step 3, utilization obtain _λReflectivity ρ with this material for test _λ, calculate the spectral absorptance k that obtains this material for test according to baer's law _{A λ}

Step 4, utilization obtain the spectral absorptance k of this material for test _{A λ}, full spectrum is carried out integration, obtain Planck mean absorption coefficient k _ApWith the equal absorption coefficient k in Luo Silan Deping _AR, and as the measurement result of trnaslucent materials absorption coefficient, finish based on the trnaslucent materials absorption coefficient of FFIR analyser and measure.

The present invention utilizes the FFIR analyser to measure the spectral absorptance of material, and utilizes baer's law to calculate the spectral absorptance of material under the situation of known materials surface spectral reflectivity; Spectral absorptance is obtained the equal absorption coefficient of Planck mean absorption coefficient and Luo Silan Deping to full spectrum integral, and this method is easy and simple to handle, and measuring speed is fast.Measuring speed is compared with existing method, has improved 10% on year-on-year basis.

Description of drawings

Fig. 1 is the structural representation based on the FFIR analyser;

Fig. 2 is the measuring principle figure of measuring method of the present invention.

Embodiment

Embodiment one, in conjunction with Fig. 1 present embodiment is described, the described trnaslucent materials absorption coefficient measuring method based on the FFIR analyser of present embodiment, it is based on, and the FFIR analyser realizes; It is based on the realization of FFIR analyser; This spectroanalysis instrument comprises: power supply 1, interferometer 2, light source 3, measuring chamber 4, total reflective mirror (5) and detector 6; Interferometer 2 comprises a total reflective mirror 2-1, No. two total reflective mirror 2-2, half-reflecting half mirror 2-3, lens 2-4 and No. three total reflective mirror 2-5; The beam emissions that light source 3 sends is to the half-reflecting half mirror 2-3 of interferometer 2, folded light beam behind half-reflecting half mirror 2-3 is returned half-reflecting half mirror 2-3 through a total reflective mirror 2-1 back reflection, after half-reflecting half mirror 2-3 transmission, be incident to lens 2-4, transmitted light beam behind half-reflecting half mirror 2-3 returns half-reflecting half mirror 2-3 through No. two total reflective mirror 2-2 back reflections, is incident to lens 2-4 after half-reflecting half mirror 2-3 reflection; Light beam after lens 2-4 transmission is incident to measuring chamber 4 through No. three total reflective mirror 2-5, and the light beam after measuring chamber 4 is measured is incident to the photosurface of detector 6 through total reflective mirror 5;

Power supply 1 is used to interferometer 2, light source 3 and detector 6 power supplies;

Measuring chamber 4 comprises test specimen frame 4-1, and test specimen frame 4-1 is used for fixedly test specimen; The center of described test specimen and the optical axis of light beam and being centered close on the straight line of total reflective mirror 5 behind No. three total reflective mirror 2-5, and light beam is vertical with the test specimen surface after No. three total reflective mirror 2-5 emissions;

It is characterized in that the concrete steps of this method are:

Step 1, open the power supply 1 of FFIR analyser, and preheating n minute, n 〉=20, preheating finishes the emittance I that a test specimen is gathered in the back _λ

Step 2, test specimen is put into measuring chamber 4, be fixed on the test specimen frame 4-1, to the emittance I of transmission _{λ, L}Gather, obtain the spectral-transmission favtor τ of this test specimen 5 _λ

The spectral transmittance τ of the test specimen that step 3, utilization obtain _λReflectivity ρ with this material for test _λ, calculate the spectral absorptance k that obtains this material for test according to baer's law _{A λ}

Step 4, utilization obtain the spectral absorptance k of this material for test _{A λ}, full spectrum is carried out integration, obtain Planck mean absorption coefficient k _ApWith the equal absorption coefficient k in Luo Silan Deping _AR, and as the measurement result of trnaslucent materials absorption coefficient, finish based on the trnaslucent materials absorption coefficient of FFIR analyser and measure.

Embodiment two, present embodiment be to the described trnaslucent materials absorption coefficient measuring method based on the FFIR analyser of embodiment one further specify the spectral-transmission favtor τ of the described test specimen 5 of step 2 _λPass through formula:

${\mathrm{\&tau;}}_{\mathrm{\&lambda;}}=\frac{I_{\mathrm{\&lambda;},L}}{I_{\mathrm{\&lambda;}}}---\left(1\right)$

Obtain; Wherein, I _{λ, L}For the absorption through test specimen finally is detected the energy that device detects,

I _λ,L=I _λ,0exp(-k _aλL) （2）

In the formula, L is the thickness of test specimen, I _{λ, 0}Spectral radiant energy for the light beam that enters test specimen inside;

I _λ,0=(1-ρ _λ)I _λ （3）。

Embodiment three, present embodiment be to the described trnaslucent materials absorption coefficient measuring method based on the FFIR analyser of embodiment one further specify the described spectral absorptance k that obtains this material for test that calculates according to baer's law of step 3 _{A λ}Formula be:

$k_{\mathrm{a\&lambda;}}=-\frac{1}{L}\ln \left(\frac{{\mathrm{\&tau;}}_{\mathrm{\&lambda;}}}{1-{\mathrm{\&rho;}}_{\mathrm{\&lambda;}}}\right)---\left(4\right)$

In the formula, L is the thickness of test specimen.

Present embodiment will obtain spectral absorptance k in formula 1 and the formula 2 formula substitution formula 3 _{A λ}With spectral-transmission favtor τ _λRelation.

Embodiment four, present embodiment be to the described trnaslucent materials absorption coefficient measuring method based on the FFIR analyser of embodiment one further specify, utilization described in the step 4 obtains the spectral absorptance of this material for test, full spectrum is carried out integration, obtain Planck mean absorption coefficient k _ApWith the equal absorption coefficient k in Luo Silan Deping _ARMethod be:

Pure absorbability translucent medium, Planck mean absorption coefficient k _ApBy formula:

$k_{\mathrm{ap}}\frac{{\&Integral;}_0^{\&infin;}{k}_{\mathrm{a\&lambda;}}{E}_{\mathrm{b\&lambda;}}\mathrm{d\&lambda;}}{\mathrm{\&sigma;}{T}^4}$ $\left(5\right)$

$=\frac{{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="HDA00003447102800011.png"\; state="\{\{state\}\}">C</figure-callout>}}_1}{\mathrm{\&sigma;}{\mathrm{<figure-callout\; id="4"\; label="T"\; filenames="HDA00003447102800011.png"\; state="\{\{state\}\}">T</figure-callout>}}^4}{\&Integral;}_0^{\&infin;}\frac{k_{\mathrm{a\&lambda;}}{\mathrm{\&lambda;}}^{-5}}{\exp [{\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="HDA00003447102800011.png"\; state="\{\{state\}\}">C</figure-callout>}}_2/\left(\mathrm{\&lambda;T}\right)]-1}\mathrm{d\&lambda;}$

Realize that in the formula, T is the test specimen temperature;

λ is wavelength;

E _{B λ}For black matrix spectral emissions power under the test specimen temperature, calculated by Planck law;

σ is Planck's constant, and its numerical value is 5.67 * 10 ^-8W/ (m ²K ⁴);

C ₁Be first radiation constant, its numerical value is 3.7418 * 10 ⁸W μ m ⁴/ m ²

C ₂Be second radiation constant, its numerical value is 1.4388 * 10 ⁴μ mK;

With spectral absorptance k _{A λ}Substitution formula 5 also utilizes numerical integration method 5 pairs of full spectrum integrals of formula to be obtained the Planck mean absorption coefficient k of test specimen _Ap

When carrying out the optically thick limit approximate treatment, the equal absorption coefficient k in Luo Silan Deping _ARObtain by father-in-law's formula 6:

$k_{\mathrm{aR}}={\&Integral;}_0^{\&infin;}{k}_{\mathrm{a\&lambda;}}\frac{{\mathrm{dE}}_b}{{\mathrm{dE}}_{\mathrm{b\&lambda;}}}\mathrm{d\&lambda;}---\left(6\right)$

In the formula, E _bBe the full spectral emissions power of the black matrix under the test specimen temperature;

dE _b=E _bλ·dλ （7）

To can get in (7) formula substitution (6) formula:

$k_{\mathrm{aR}}={\&Integral;}_0^{\&infin;}{k}_{\mathrm{a\&lambda;}}\frac{E_b}{{\mathrm{dE}}_{\mathrm{b\&lambda;}}/\mathrm{d\&lambda;}}\mathrm{d\&lambda;}$ $\left(8\right)$

$={\&Integral;}_0^{\&infin;}\frac{k_{\mathrm{a\&lambda;}}{\mathrm{\&lambda;}}^{2}T\left\{\exp \right[{\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="HDA00003447102800011.png"\; state="\{\{state\}\}">C</figure-callout>}}_2/\left(\mathrm{\&lambda;T}\right)]-1\}}{(C_2-5\mathrm{\&lambda;T})\exp [{\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="HDA00003447102800011.png"\; state="\{\{state\}\}">C</figure-callout>}}_2/\left(\mathrm{\&lambda;T}\right)]+5\mathrm{\&lambda;T}}\mathrm{d\&lambda;}$

With spectral absorptance k _{A λ}Substitution formula 8 also utilizes numerical integration method 8 pairs of full spectrum integrals of formula to be obtained the equal absorption coefficient k in Luo Silan Deping of test specimen _AR。

Embodiment five, present embodiment are that the scope of the spectrum described in the step 3 is 2.5-25 μ m to the further specifying of the described trnaslucent materials absorption coefficient measuring method based on the FFIR analyser of embodiment one.

Embodiment six, present embodiment are that the described test specimen of step 2 is the square that length and width are 5cm to the further specifying of the described trnaslucent materials absorption coefficient measuring method based on the FFIR analyser of embodiment one.

Test specimen is made square that length and width are 5cm be convenient to measurement to test specimen.

The present invention is not limited to above-mentioned embodiment, can also be the reasonable combination of technical characterictic described in the respective embodiments described above.

Claims (6)

1. based on the trnaslucent materials absorption coefficient measuring method of FFIR analyser, it is based on, and the FFIR analyser realizes; This spectroanalysis instrument comprises: power supply (1), interferometer (2), light source (3), measuring chamber (4), total reflective mirror (5) and detector (6); Interferometer (2) comprises a total reflective mirror (2-1), No. two total reflective mirrors (2-2), half-reflecting half mirror (2-3), lens (2-4) and No. three total reflective mirrors (2-5); The beam emissions that light source (3) sends is to the half-reflecting half mirror (2-3) of interferometer (2), folded light beam behind half-reflecting half mirror (2-3) is returned half-reflecting half mirror (2-3) through a total reflective mirror (2-1) back reflection, after half-reflecting half mirror (2-3) transmission, be incident to lens (2-4), transmitted light beam behind half-reflecting half mirror (2-3) returns half-reflecting half mirror (2-3) through No. two total reflective mirrors (2-2) back reflection, is incident to lens (2-4) after half-reflecting half mirror (2-3) reflection; Light beam after lens (2-4) transmission is incident to measuring chamber (4) through No. three total reflective mirrors (2-5), and the light beam after measuring chamber (4) is measured is incident to the photosurface of detector (6) through total reflective mirror (5);

Power supply (1) is used to interferometer (2), light source (3) and detector (6) power supply;

Measuring chamber (4) comprises test specimen frame (4-1), and test specimen frame (4-1) is used for fixedly test specimen; The center of described test specimen and the optical axis of light beam and being centered close on the straight line of total reflective mirror (5) behind No. three total reflective mirrors (2-5), and light beam is vertical with the test specimen surface after No. three total reflective mirrors (2-5) emission;

It is characterized in that the concrete steps of this method are:

Step 1, open the power supply (1) of FFIR analyser, and preheating n minute, n 〉=20, preheating finishes the emittance I that a test specimen is gathered in the back _λ

Step 2, test specimen is put into measuring chamber (4), be fixed on the test specimen frame (4-1), to the emittance I of transmission _{λ, L}Gather, obtain the spectral-transmission favtor τ of this test specimen (5) _λ

The spectral transmittance τ of the test specimen that step 3, utilization obtain _λReflectivity ρ with this material for test _λ, calculate the spectral absorptance k that obtains this material for test according to baer's law _{A λ}

Step 4, utilization obtain the spectral absorptance k of this material for test _{A λ}, full spectrum is carried out integration, obtain Planck mean absorption coefficient k _ApWith the equal absorption coefficient k in Luo Silan Deping _AR, and as the measurement result of trnaslucent materials absorption coefficient, finish based on the trnaslucent materials absorption coefficient of FFIR analyser and measure.

2. the trnaslucent materials absorption coefficient measuring method based on the FFIR analyser according to claim 1 is characterized in that the spectral-transmission favtor τ of the described test specimen of step 2 (5) _λPass through formula:

${\mathrm{\&tau;}}_{\mathrm{\&lambda;}}=\frac{I_{\mathrm{\&lambda;},L}}{I_{\mathrm{\&lambda;}}}---\left(1\right)$

Obtain; Wherein, I _{λ, L}For the absorption through test specimen finally is detected the energy that device detects,

I _λ,L=I _λ,0exp(-k _aλL) （2）

In the formula, L is the thickness of test specimen, I _{λ, 0}Spectral radiant energy for the light beam that enters test specimen inside;

I _λ,0=(1-ρ _λ)I _λ （3）。

3. the trnaslucent materials absorption coefficient measuring method based on the FFIR analyser according to claim 1 is characterized in that, the described spectral absorptance k that obtains this material for test that calculates according to baer's law of step 3 _{A λ}Formula be:

$k_{\mathrm{a\&lambda;}}=-\frac{1}{L}\ln \left(\frac{{\mathrm{\&tau;}}_{\mathrm{\&lambda;}}}{1-{\mathrm{\&rho;}}_{\mathrm{\&lambda;}}}\right)---\left(4\right)$

In the formula, L is the thickness of test specimen.

4. the trnaslucent materials absorption coefficient measuring method based on the FFIR analyser according to claim 1, it is characterized in that, utilization described in the step 4 obtains the spectral absorptance of this material for test, and full spectrum is carried out integration, obtains Planck mean absorption coefficient k _ApWith the equal absorption coefficient k in Luo Silan Deping _ARMethod be:

Pure absorbability translucent medium, Planck mean absorption coefficient k _ApBy formula:

$k_{\mathrm{ap}}\frac{{\&Integral;}_0^{\&infin;}{k}_{\mathrm{a\&lambda;}}{E}_{\mathrm{b\&lambda;}}\mathrm{d\&lambda;}}{\mathrm{\&sigma;}{T}^4}$ $\left(5\right)$

$=\frac{C_1}{\mathrm{\&sigma;}{T}^4}{\&Integral;}_0^{\&infin;}\frac{k_{\mathrm{a\&lambda;}}{\mathrm{\&lambda;}}^{-5}}{\exp [C_2/\left(\mathrm{\&lambda;T}\right)]-1}\mathrm{d\&lambda;}$

Realize that in the formula, T is the test specimen temperature;

λ is wavelength;

E _{B λ}For black matrix spectral emissions power under the test specimen temperature, calculated by Planck law;

σ is Planck's constant, and its numerical value is 5.67 * 10 ^-8W/ (m ²K ⁴);

C ₁Be first radiation constant, its numerical value is 3.7418 * 10 ⁸W μ m ⁴/ m ²

C ₂Be second radiation constant, its numerical value is 1.4388 * 10 ⁴μ mK;

With spectral absorptance k _{A λ}Substitution formula 5 also utilizes numerical integration method 5 pairs of full spectrum integrals of formula to be obtained the Planck mean absorption coefficient k of test specimen _Ap

When carrying out the optically thick limit approximate treatment, the equal absorption coefficient k in Luo Silan Deping _ARObtain by formula 6:

$k_{\mathrm{aR}}={\&Integral;}_0^{\&infin;}{k}_{\mathrm{a\&lambda;}}\frac{{\mathrm{dE}}_b}{{\mathrm{dE}}_{\mathrm{b\&lambda;}}}\mathrm{d\&lambda;}---\left(6\right)$

In the formula, E _bBe the full spectral emissions power of the black matrix under the test specimen temperature;

dE _b=E _bλ·dλ （7）

To get in the formula 7 formula substitution formula 6:

$k_{\mathrm{aR}}={\&Integral;}_0^{\&infin;}{k}_{\mathrm{a\&lambda;}}\frac{E_b}{{\mathrm{dE}}_{\mathrm{b\&lambda;}}/\mathrm{d\&lambda;}}\mathrm{d\&lambda;}$ $---\left(8\right)$

$={\&Integral;}_0^{\&infin;}\frac{k_{\mathrm{a\&lambda;}}{\mathrm{\&lambda;}}^{2}T\left\{\exp \right[C_2/\left(\mathrm{\&lambda;T}\right)]-1\}}{(C_2-5\mathrm{\&lambda;T})\exp [C_2/\left(\mathrm{\&lambda;T}\right)]+5\mathrm{\&lambda;T}}\mathrm{d\&lambda;}$

With spectral absorptance k _{A λ}Substitution formula 8 also utilizes numerical integration method 8 pairs of full spectrum integrals of formula to be obtained the equal absorption coefficient k in Luo Silan Deping of test specimen _AR

5. the trnaslucent materials absorption coefficient measuring method based on the FFIR analyser according to claim 1 is characterized in that, the scope of the spectrum described in the step 3 is 2.5-25 μ m.

6. the trnaslucent materials absorption coefficient measuring method based on the FFIR analyser according to claim 1 is characterized in that the described test specimen of step 2 is the square that length and width are 5cm.

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