CN102589714A - Temperature measuring device based on high-pressure gas Rayleigh-Brillouin scattering spectrum - Google Patents

Abstract

The invention relates to a temperature measuring device based on high-pressure gas Rayleigh-Brillouin scattering spectrum. The device can probe the Brillouin frequency shifting rate in the Rayleigh-Brillouin scattering spectrum at different pressures to measure acoustic velocity at different pressures so as to achieve temperature retrieval. 355nm single-die laser enters the high pressure gas to mutually interact with various gas molecules in the gas; the scattering signal passes through an F-P scanning interferometer and is received by a photon detector, therefore, the Rayleigh-Brillouin scattering spectrum of the high pressure gas can be obtained. According to the temperature measuring device, the precise measurement on the gas temperature at different pressures is achieved through analysis and calculation of the spectral function.

Description

A kind of device based on gases at high pressure Rayleigh-Brillouin scattering spectrum measurement temperature

Technical field:

The present invention relates to a kind of experimental provision that comes gas temperature under the different pressure of inverting based on gases at high pressure Rayleigh-Brillouin scattering frequency spectrum.

Background technology:

In commercial production, generally use thermopair, thermal resistance, glass liquid thermometer equitemperature sensor measurement temperature.When measuring high temperature, high pressure draught, sensor is when measuring junction thermal equilibrium, facing to the heat transfer influence of complicacy.Therefore, in measuring process, the temperature of temperature sensor also is not equal to the actual temperature of air-flow.And the measurement of the high-temperature gas transient temperature difficult point in the temperature survey especially, main cause is that temperature is high, pressure is big, temperature changing speed is fast.

The common method of measuring high temperature and high pressure gas at present is divided into contact and contactless.When measuring with contacting temperature measurement method, because temperature-sensing element is to the thermal inertia of the disturbance in temperature field, sensor and the limitation in thermometric zone, so its measurement result is not satisfactory.Contactless temperature-measuring method, particularly otpical thermometry, because advantage such as its measurement range is big, the dut temperature field soon, is not disturbed in response and transient response is good, thereby have unique advantages aspect the measurement in temperature field.

Proposed in the literary composition a kind of novel, realize method through measuring the atmosphere Brillouin shift to the real-time detection of gases at high pressure temperature.Because the Brillouin shift of gases at high pressure becomes relation one to one with atmospheric temperature, therefore can be finally inversed by temperature level as long as measure the Brillouin shift amount of gases at high pressure accurately.

Summary of the invention:

In order to realize the accurate measurement of gases at high pressure temperature, we have proposed a kind of high pressure Rayleigh-Brillouin scattering frequency spectrum that utilizes and have come the new method of inverting temperature.This method is to measure the Brillouin shift of gases at high pressure through formula (1), realizes the measurement of the velocity of sound, and theoretical research shows that the temperature of ideal gas and the velocity of sound are obeyed formula (2), so formula (3) is obeyed in can derive temperature and Brillouin's frequency displacement:

$\mathrm{\Δ\υ}=\±\frac{2\mathrm{nv}}{\mathrm{\λ}}\sin \frac{\mathrm{\θ}}{2}---\left(1\right)$

$v=\sqrt{\frac{\mathrm{\γ}\·R\·T}{m}}---\left(2\right)$

$T=\frac{{\mathrm{m\&lambda;}}^2\mathrm{\&Delta;}{\mathrm{\&upsi;}}^2}{{4\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HSA00000673985300011.png"\; state="\{\{state\}\}">n</figure-callout>}}^2\mathrm{\&gamma;R}{\sin }^2\frac{\mathrm{\&theta;}}{2}}---\left(3\right)$

Δ υ is the Brillouin shift in the medium in the formula (1), and n is a medium refraction index, and v is the velocity of sound in the medium, and λ is the optical maser wavelength of incident, and θ is a scattering angle, ± corresponding Stokes and anti-Stokes light

V is the velocity of sound in the medium in the formula (2), and γ is the specific heat ratio of ideal gas, and R is an ideal gas constant, and T is a gas temperature, and m is the molecular weight of air on the sea level

So, as long as experimentally confirmed can be finally inversed by the gases at high pressure temperature according to formula (3) by frequency displacement Δ υ.

The invention provides a kind of experimental provision of new measurement gases at high pressure temperature, realized the accurate measurement of high pressure temperature.

Detection system of the present invention comprises: pouring-in pulsed laser or continuous wave laser (1), the total reflective mirror of 355nm (2,3,4,13), filter system (7); Collimation and filter system (11,12), slit (10,18,21,23), convex lens (5,8,11,14,17,19,20,22); Scattering cell (6); Scanning interferometer (15), energy recovery pond (9), signal detecting device (16).

The scheme of technical solution problem of the present invention is: laser instrument (1) output wavelength is the narrow band light of the vertical polarization of 355nm; By 355nm total reflective mirror (2) 95% light is reflexed to total reflective mirror (3); 5% transmittance is to filter system (7); Behind the planoconvex lens (8), pass through scattering cell (6), be used for the correction of light path.Light through total reflective mirror (3) passes through total reflective mirror (4) and condenser lens (5) again, is injected in the scattering cell (6), interacts with gas molecule, produces scattered signal, finally sees through scattering cell and gets into energy recovery pond (9).Device is from 90 ° of orientation detection scattered signals; Be coupled in the beam splitting system (15) for what guarantee that scattered signal can maximal efficiency; Scattered signal is through slit (10), collimation and filter system (11,12), total reflective mirror (13); Focused in the scanning interferometer (15) by convex lens (14), final scattered signal is observed by photon detector (PMT) and computing machine.

The technical advantage of this new method and detection system is conspicuous.One, the Rayleigh-Brillouin scattering frequency spectrum under the employing high pressure comes the gas temperature of the different pressure of inverting; Promptly after obtaining the scattering frequency spectrum, utilize the Brillouin shift formula; Through computer program real time inversion temperature, be a kind of new utilize spectroscopic methodology measure the high pressure temperature method.Two, detection system has very high reliability and degree of accuracy, is mainly reflected in: 1. adopt 355nm laser Rayleigh-Brillouin scattering frequency spectrum under high pressure, can adopt tangible Brillouin scattering peak, realize the accurate inverting of temperature.2. adopt the scan-type F-P interferometer that places under the constant temperature as the high resolving power beam splitting system, realize accurate measurement Brillouin shift.3. the F-P interferometer is placed constant temperature oven, reduced the influence of external environment, improved the reliability and stability of detection system it.4. scattering cell places all adjustable regulating box of temperature, pressure, and the gas that can simulate different pressure, temperature is realized the temperature survey under the different pressure.5. scattering cell adopts the design of Brewster window, has weakened the reflected light in the pond greatly, has strengthened scattered signal.6. use photon detector and photon collection card detecting light spectrum image, can obtain high sensitivity, high-resolution spectrum picture.

Description of drawings:

Accompanying drawing 1 has provided the sniffer schematic diagram of the Rayleigh-Brillouin scattering frequency spectrum of gases at high pressure.

Accompanying drawing 2 has provided the schematic diagram of filter system in the device.

Accompanying drawing 3 provides the optical filtering and the spot diameter of scattered signal in the device and integrates schematic diagram.

Accompanying drawing 4 has provided the experimental spectrum figure that photon detector is gathered.

Embodiment

Embodiment 1:

Shown in accompanying drawing 1, this device comprises: pouring-in pulsed laser or continuous wave laser (1), the total reflective mirror of 355nm (2,3,4,13); Filter system (7), collimation and filter system (12), slit (10,18,21,23); Convex lens (5,8,11,14,17,19,20,22), scattering cell (6), scanning interferometer (15); Energy recovery pond (9), signal detecting device (16).

Laser instrument (1) output wavelength is the narrow band light of the vertical polarization of 355nm, through 355nm total reflective mirror (2) 95% light is reflexed to total reflective mirror (3), and 5% transmittance, is injected in the scattering cell (6) behind the planoconvex lens (8) to filter system (7), is used for the correction of light path.Light process total reflective mirror (4) and condenser lens (5) through total reflective mirror (3) are injected in the scattering cell (6), interact with gas molecule, produce scattered signal, finally see through scattering cell and get into energy recovery pond (9).Device is from 90 ° of orientation detection scattered signals; Be coupled in the beam splitting system (15) for what guarantee that scattered signal can maximal efficiency; Scattered signal is through filter light slit (10), collimation and filter system (11,12), total reflective mirror (13); Focused in the scanning interferometer (15) by convex lens (14), final scattered signal is observed by signal detecting device (16) and computing machine.

Embodiment 2:

Shown in accompanying drawing 2, filter system (7) comprising: convex lens (17,19) and slit (18)

For calibration experiments device in experiment, the light with 5% is made as reference light, and in order to guarantee the quality of laser beam, 5% laser is through convex lens 17 (f ₁₇=10cm), slit 18 (D ₁₈=50um), convex lens 19 (f ₁₉=spatial filtering the system that 10cm) formed carries out filtering, and purpose is for the space of eliminating light beam rises and falls, and makes the field strength distribution homogenising on its cross section.

Embodiment 3:

Shown in accompanying drawing 3, optical filtering comprising with spot diameter integration system (12): convex lens (20,22) and slit (21,23).

In order in experiment, to detect faint scattered signal, realize the detection of brillouin scattering signal, must scattered signal be coupled in the high-resolution beam splitting system (15) as much as possible, so before beam splitting system, designed slit 10, lens 11 (D ₁₀=0.1mm, f ₁₁=75mm) with optical filtering and spot diameter integration system (12), signal at first passes through slit 10 (D ₁₀=0.1mm) reduce the space divergence angle, (f=75mm) collimates by lens 11, then by lens 20 (f ₂₀=50mm) focus on slit 21 (D ₂₁=50um) enterprising row space filtering is at last by lens 22 (f ₂₂=50mm) collimation once more, in order spot diameter to be limited in the scanning interferometer acceptable scope, with it through slit 23 (D ₂₃=1.5mm) carry out spot diameter to proofread and correct, finally let hot spot be coupled among the F-P to greatest extent.

Accompanying drawing 4 is when carrying out gas Rayleigh under the high pressure-brillouin frequency spectrometry with the detection system that accompanying drawing 1 and accompanying drawing 2 and accompanying drawing 3 are formed, the spectrogram that photon detector collects.Shown in accompanying drawing 4,, just can be finally inversed by the gas temperature under the different high pressure according to the Brillouin shift formula as long as measure brillouin scattering signal.

Claims (4)

1. one kind is come the device of inverting gas temperature based on high pressure Rayleigh-Brillouin scattering frequency spectrum, and this device comprises pouring-in pulsed laser or continuous wave laser (1), the total reflective mirror of 355nm (2,3,4,13); Filter system (7), collimation and filter system (12), slit (10,18,21,23); Convex lens (5,8,11,14,17,19,20,22), scattering cell (6), scanning interferometer (15); Energy recovery pond (9), signal detecting device (16).

Laser instrument (1) output wavelength is the narrow band light of the vertical polarization of 355nm, through 355nm total reflective mirror (2) 95% light is reflexed to total reflective mirror (3), and 5% transmittance, is injected in the scattering cell (6) behind the planoconvex lens (8) to filter system (7), is used for the correction of light path.Light process total reflective mirror (4) and condenser lens (5) through total reflective mirror (3) are injected in the scattering cell (6), interact with gas molecule, produce scattered signal, finally see through scattering cell and get into energy recovery pond (9).Device is from 90 ° of orientation detection scattered signals; Be coupled in the beam splitting system (15) for what guarantee that scattered signal can maximal efficiency; Scattered signal is through filter light slit (10), collimation and filter system (11,12), total reflective mirror (13); Focused in the scanning interferometer (15) by convex lens (14), final scattered signal is observed by signal detecting device (16) and computing machine.

2. as claimed in claim 1ly come the device of inverting gas temperature, it is characterized in that based on high pressure Rayleigh-Brillouin scattering frequency spectrum: the design of scattering cell (6), one, adopt Brewster window, can reduce the reflected light of scattering cell greatly; Two, can simulate the gas of different temperatures and pressure through the adjusting of external temperature, pressure, realize the measurement of high-temperature gas under the different pressure.

3. as claimed in claim 1ly come the device of inverting gas temperature based on high pressure Rayleigh-Brillouin scattering frequency spectrum; It is characterized in that: the placement of f-p scanning interferometer and parameters of choice; Realized the detection of faint scattered signal; One, f-p is placed the constant temperature oven of Controllable Temperature, can guarantee stability and reliability that f-p uses; Two, the major parameter of f-p is: Free Spectral Range 30GHZ, the specular reflectance of F-P is 99%, centre wavelength 355nm, bandwidth 230MHZ, fineness 130.

4. as claimed in claim 1ly come the device of inverting temperature based on high pressure Rayleigh-Brillouin scattering frequency spectrum; It is characterized in that: survey the selection of 50um slit (21) in the light path; Implementation space filtering, the parasitic light in the filtering scattered signal makes the detection of scattered signal become possibility.

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