An experimental system for three-dimensional measurement of flame radiation spectrum and intensity

Abstract

The invention discloses an experimental system for three-dimensional measurement of flame radiation spectrum and intensity. The flame combustion device is used to generate flame; the data acquisition device comprises a first optical fiber, a first optical fiber spectrometer and a translation and rotation displacement mechanism; the sensing end of the first optical fiber faces the flame, the first optical fiber spectrometer obtains the radiation intensity of the flame, and the first optical fiber is arranged in the translation and rotation displacement mechanism, so that the spectrum scanning and acquisition of the flame at multiple angles in space can be realized; the calibration device comprises a standard light source, a second optical fiber and a second optical fiber spectrometer; the sensing end of the second optical fiber faces the standard light source; the second optical fiber spectrometer obtains the radiation intensity of the standard light source; the radiation intensity of the standard light source obtained by the second optical fiber spectrometer is compared with the radiation information of the standard light source at the factory, the wavelength response system error existing in the second optical fiber spectrometer and the first optical fiber spectrometer is corrected, the error of the test system is reduced, and the accuracy of the flame temperature obtained by the subsequent calculation is improved.

Description

Technical Field

[0001] The invention relates to the technical field of combustion diagnosis and spectrum measurement, and in particular to an experimental system for three-dimensional measurement of flame radiation spectrum and intensity. Background Art

[0002] In the research of various new engine technologies, combustion chamber temperature and temperature distribution have always been an important basis for evaluating engine performance and predicting engine life. However, with the continuous increase in combustion chamber and plume temperatures, a temperature measurement technology suitable for high-temperature measurement is urgently needed. In the gas temperature measurement technology for engine applications, it is generally believed that the contact measurement method will interfere with the flow field, and it is necessary to develop an optical measurement method that does not require an external light source and has strong environmental adaptability.

[0003] Under high temperature conditions, the vibrational energy levels of a considerable proportion of molecules are excited to high energy states. These high energy level particles will transition to lower energy levels and radiate photons with specific frequencies. By using a spectral testing system, the wavelength information corresponding to these spontaneously radiated photons can be collected to infer the energy level distribution of its high energy level particles, that is, the vibration and rotation temperatures of the corresponding components. In most combustion systems, the vibration and rotation temperatures are consistent with the translational temperatures, so the gas temperature can be quantitatively extracted by measuring the thermal radiation spectral characteristics of the quasi-equilibrium molecules.

[0004] However, the basis of all measurements requires obtaining the radiation spectrum of the target at different angles and the quantitative radiation intensity to invert multi-dimensional temperature data. The required measurement system must have spatial scanning capabilities. Summary of the invention

[0005] The purpose of the present invention is to provide an experimental system for three-dimensional measurement of flame radiation spectrum and intensity, which utilizes a translation and rotation displacement mechanism to drive a fiber optic spectrometer to collect flame radiation spectra at different positions in space. At the same time, a calibration device that can quantify the radiation intensity is provided to improve the measurement accuracy and solve the technical problems existing in the prior art.

[0006] In order to solve the above technical problems, the present invention specifically provides the following technical solutions: an experimental system for three-dimensional measurement of flame radiation spectrum and intensity, comprising:

[0007] A flame combustion device for generating flame;

[0008] The data acquisition device comprises a first optical fiber, a first optical fiber spectrometer and a translation and rotation displacement mechanism; the sensing end of the first optical fiber faces the flame, the first optical fiber couples the light of the flame into the first optical fiber spectrometer for spectral analysis to obtain the radiation spectrum and radiation intensity of the flame, and the first optical fiber is arranged in the translation and rotation displacement mechanism;

[0009] The calibration device includes a standard light source, a second optical fiber and a second optical fiber spectrometer; the sensing end of the second optical fiber faces the standard light source; the second optical fiber couples the light of the standard light source into the second optical fiber spectrometer for spectral analysis to obtain the radiation intensity of the standard light source; the second optical fiber spectrometer and the first optical fiber spectrometer are the same spectrometers; the radiation intensity of the standard light source obtained by the second optical fiber spectrometer is compared with the radiation information of the standard light source at the factory, and the wavelength response system error existing in the second optical fiber spectrometer and the first optical fiber spectrometer is corrected;

[0010] The computer is respectively connected to the first fiber optic spectrometer and the second fiber optic spectrometer for communication, and receives and stores the data output by the first fiber optic spectrometer and the second fiber optic spectrometer.

[0011] Furthermore, the data acquisition device also includes an aperture and a lens, both of which are arranged on the translation and rotation displacement mechanism; the light path received by the first optical fiber passes through the aperture and the lens in sequence.

[0012] Furthermore, the flame combustion device includes a burner, a premixing tank and a plurality of high-pressure gas cylinders, the burner and the premixing tank are connected, and the plurality of high-pressure gas cylinders are respectively connected to the premixing tanks; and the high-pressure gas cylinders store flammable gas.

[0013] Furthermore, a water cooling pump is provided at the burner; and a flame arrester is provided on the pipeline between the burner and the premixing tank.

[0014] Furthermore, the calibration device also includes a baffle; the baffle is arranged between the standard light source and the second optical fiber; a through hole is provided on the baffle, and the light path received by the second optical fiber passes through the through hole.

[0015] Furthermore, the calibration device also includes a black plate; the black plate is perpendicular to the reverse extension line of the light path received by the second optical fiber.

[0016] Furthermore, the distance between the black plate and the standard light source is twice the distance between the standard light source and the second optical fiber.

[0017] Compared with the prior art, the present invention has the following beneficial effects: the optical fiber spectrometer used in the present invention is a non-contact measuring device, which will not interfere with the propagation of flames and the establishment of flow fields, and guarantees the integrity of the measured object to the greatest extent.

[0018] The spectrum acquisition device using a translation and rotation displacement mechanism combined with an optical fiber can realize spectrum scanning and acquisition of a target at multiple spatial angles.

[0019] The use of standard light sources such as halogen tungsten lamps to correct the measurement system error reduces the error of the test system and improves the accuracy of the flame temperature obtained in subsequent calculations. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0021] Figure 1 This is a schematic diagram of the structure of the data acquisition device in this application for collecting the radiation spectrum intensity of the flame;

[0022] Figure 2 It is a structural schematic diagram of the calibration device in this application;

[0023] Figure 3 It is a partial schematic diagram of the rotating platform in the translation and rotation displacement mechanism in this application.

[0024] The numbers in the figure represent the following:

[0025] 1-first optical fiber, 21-first optical fiber spectrometer, 22-second optical fiber spectrometer, 3-computer, 4-translation and rotation displacement mechanism, 5-standard light source, 6-second optical fiber, 7-aperture, 8-lens, 9-burner, 10-premixing tank, 11-high-pressure gas cylinder, 12-water cooling pump, 13-flame arrester, 14-baffle, 15-black plate, 16-pressure reducing valve, 17-flow meter. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] like Figure 1-Figure 3 As shown, the present invention provides an experimental system for three-dimensional measurement of flame radiation spectrum and intensity, including a flame combustion device, a data acquisition device and a calibration device.

[0028] The flame combustion device is used to generate a flame; the data acquisition device includes a first optical fiber 1, a first optical fiber spectrometer 21 and a translation and rotation displacement mechanism 4; the sensing end of the first optical fiber 1 faces the flame, and the first optical fiber 1 couples the light of the flame into the first optical fiber spectrometer 21 for spectral analysis to obtain the radiation spectrum and radiation intensity of the flame, and the first optical fiber 1 is arranged in the translation and rotation displacement mechanism 4.

[0029] The calibration device includes a standard light source 5, a second optical fiber 6 and a second optical fiber spectrometer 22; the sensing end of the second optical fiber 6 faces the standard light source 5; the second optical fiber 6 couples the light of the standard light source 5 into the second optical fiber spectrometer 22 for spectral analysis to obtain the radiation intensity of the standard light source 5.

[0030] The computer 3 is respectively connected to the first fiber optic spectrometer 21 and the second fiber optic spectrometer 22 for communication, and receives and stores the data output by the first fiber optic spectrometer 22 and the second fiber optic spectrometer 22, wherein the data output by the first fiber optic spectrometer 22 is used to calculate the flame temperature, and the data output by the second fiber optic spectrometer 22 is used to correct the error between the first fiber optic spectrometer 22 and the second fiber optic spectrometer 22.

[0031] The first fiber optic spectrometer 21 and the second fiber optic spectrometer 22 are the same type of spectrometers, and adopt industrial-grade fiber optic spectrometers, which can be quickly deployed in various harsh test environments and increase their mobility, greatly reducing the use cost of the entire test system.

[0032] The first optical fiber 1 is arranged on the translation and rotation displacement mechanism 4, and the sensing end of the first optical fiber 1 faces the flame; the translation and rotation displacement mechanism can be used to drive the optical fiber spectrometer by outputting a 5V TTL signal to obtain the spectral information of the target flame at different angles.

[0033] In this embodiment, the first optical fiber 1 is a splitting optical fiber, and the wavelength, energy, polarization and other characteristics of the flame light are redistributed into two groups of optical fibers through the optical fiber beam splitter 11, and then respectively coupled to the first optical fiber spectrometer 21 for spectral analysis. The two groups of first optical fiber spectrometers in this embodiment use BSV6002a and BSV6805 from the market of Hangzhou Boyuan Optoelectronics Technology Co., Ltd., and the wavelength detection ranges are 250-1100nm and 900-1700nm respectively; two sets of spectral data are obtained for subsequent temperature calculations.

[0034] In this example, the standard light source 5 uses a halogen tungsten lamp, and the test distance between the halogen tungsten lamp and the second optical fiber 6 is 500 mm; the calibration device compares the radiation intensity of the halogen tungsten lamp obtained by the second optical fiber spectrometer 22 with the radiation information of the halogen tungsten lamp at the factory, and corrects the wavelength response system error of the second optical fiber spectrometer 22; since the second optical fiber spectrometer 22 and the first optical fiber spectrometer 21 are the same type of spectrometers, the wavelength response system error of the first optical fiber spectrometer 21 is corrected, thereby reducing the error in measuring the flame radiation intensity and improving the accuracy of the flame temperature obtained by subsequent calculations.

[0035] At the same time, the halogen tungsten lamp is equipped with a tungsten lamp current controller, which can control the light radiation intensity at a fixed distance by setting the input current or voltage; by comparing with the standard information of the wavelength meter at the factory, the wavelength offset of the fiber optic spectrometer, the attenuation rate of the light receiving system and the error value of the obtained radiation intensity can be calibrated, thereby minimizing the error of the test system and improving the accuracy of temperature measurement.

[0036] like Figure 1 As shown, the data acquisition device also includes an aperture 7 and a lens 8. Before the light emitted by the flame is received by the first optical fiber 1, it first passes through the aperture 7 and the lens 8 in sequence. The aperture 7 and the lens 8 are also arranged on the translation and rotation displacement mechanism 4. The combination of the aperture and the lens is an important device for collecting light. The adjustable aperture can control the size of the light flux, and combined with the lens, it can realize the measurement of a smaller divergence angle.

[0037] The flame combustion device includes a burner 9, a premixing tank 10 and a plurality of high-pressure gas cylinders 11. The burner 9 is connected to the premixing tank 10, and the plurality of high-pressure gas cylinders 11 are respectively connected to the premixing tank 10. The high-pressure gas cylinders 11 store flammable gas, and the gas in the high-pressure gas cylinders passes through a pressure reducing valve and a flow meter into the premixing tank for full mixing and then is introduced into the burner, including N2 high-pressure gas cylinders, O2 high-pressure gas cylinders and CH4 high-pressure gas cylinders.

[0038] The N2 in the high-pressure gas cylinder assembly can be used to adjust the equivalence ratio of the experimental gas flow or to purge the system pipelines before and after the experiment and to detect the air tightness of the propellant supply system, while ensuring the accuracy of the equivalence ratio of the experimental gas flow and being able to be quickly repeated.

[0039] In this embodiment, the flow meters are all produced by Bronkhorst, and their range is 0-10SLM;

[0040] In this embodiment, the adjustable range of the pressure reducing valve outlet pressure is 0.1-1 MPa.

[0041] A water cooling pump 12 is provided at the burner 9; a flame arrester 13 is provided on the pipeline between the burner 9 and the premixing tank 10. The water cooling pump needs to be kept open at all times during the experiment to ensure that the burner body will not be burned by the high-temperature flame during the experiment.

[0042] like Figure 2 As shown, a baffle 14 is provided between the halogen tungsten lamp and the second optical fiber 6. By adjusting the size of the hole on the baffle, the luminous flux is adjusted, and then the radiation intensity of the light received by the second optical fiber 6 is adjusted; a black plate 15 is provided on the other side of the halogen tungsten lamp relative to the second optical fiber 6; the distance between the black plate 15 and the halogen tungsten lamp is twice the distance between the halogen tungsten lamp and the second optical fiber 6, and the black baffle is used to eliminate the influence of ambient diffuse reflection.

[0043] The quantitative radiation intensity collected by the second optical fiber 6 is calculated by the formula, such as the working voltage of the tungsten lamp is 6.5A, the voltage is about 30V, and the wavelength range is 250-2400nm. The radiation power at the reference point 0.5m away from the tungsten lamp can be calculated by:

[0044] I(mW / m2nm)=λ-5×exp(A+B / λ)×(C+D / λ+E / λ2+F / λ3+G / λ4+H / λ5), calculated, where:

[0045] A = 43.0982199173555;

[0046] B = -4448.46561336629;

[0047] C = 0.917870155410425;

[0048] D = 216.989071328336;

[0049] E = -189679.911752733;

[0050] F = 67787682.4735582;

[0051] G = -9192368582.79683.

[0052] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present application within the essence and protection scope of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present application.

Claims

1. An experimental system for three-dimensional measurement of flame radiation spectrum and intensity, characterized in that: include: A flame combustion device for generating flame; The data acquisition device comprises a first optical fiber (1), a first optical fiber spectrometer (21) and a translation and rotation displacement mechanism (4); the sensing end of the first optical fiber (1) faces the flame, the first optical fiber (1) couples the light of the flame into the first optical fiber spectrometer (21) for spectral analysis, and obtains the radiation spectrum and radiation intensity of the flame, and the first optical fiber (1) is arranged in the translation and rotation displacement mechanism (4); A calibration device, comprising a standard light source (5), a second optical fiber (6) and a second optical fiber spectrometer (22), wherein the sensing end of the second optical fiber (6) faces the standard light source (5), and the second optical fiber (6) couples light from the standard light source (5) into the second optical fiber spectrometer (22) for spectral analysis to obtain the radiation intensity of the standard light source; The standard light source (5) uses a halogen tungsten lamp, which is equipped with a tungsten lamp current controller, and controls the light radiation intensity at a fixed distance by setting the input current or voltage. The data output by the second optical fiber spectrometer (22) is compared with the factory information of the standard light source to correct the wavelength response system error existing in the second optical fiber spectrometer (22) and the first optical fiber spectrometer (21); That is, the calibration device compares the radiation intensity of the halogen tungsten lamp obtained by the second optical fiber spectrometer (22) with the radiation information of the halogen tungsten lamp at the factory, so as to correct the wavelength response system error existing in the second optical fiber spectrometer (22), and then correct the wavelength response system error existing in the first optical fiber spectrometer (21); the data output by the first optical fiber spectrometer (21) is used to calculate the flame temperature after correction; A computer (3) is respectively connected to the first optical fiber spectrometer (21) and the second optical fiber spectrometer (22) for communication, and receives and stores data output by the first optical fiber spectrometer (21) and the second optical fiber spectrometer (22); wherein the second optical fiber spectrometer (22) and the first optical fiber spectrometer (21) are the same type of spectrometers.

2. The experimental system for three-dimensional measurement of flame radiation spectrum and intensity according to claim 1, characterized in that: The data acquisition device further comprises an aperture (7) and a lens (8), both of which are arranged on the translation and rotation displacement mechanism (4); the light path received by the first optical fiber (1) passes through the aperture (7) and the lens (8) in sequence.

3. The experimental system for three-dimensional measurement of flame radiation spectrum and intensity according to claim 1, characterized in that: The flame combustion device comprises a burner (9), a premixing tank (10) and a plurality of high-pressure gas cylinders (11); the burner (9) and the premixing tank (10) are connected, and the plurality of high-pressure gas cylinders (11) are respectively connected to the premixing tanks (10); and the high-pressure gas cylinders (11) store flammable gas.

4. The experimental system for three-dimensional measurement of flame radiation spectrum and intensity according to claim 3, characterized in that: A water cooling pump (12) is provided at the burner (9); and a flame arrester (13) is provided on the pipeline between the burner (9) and the premixing tank (10).

5. The experimental system for three-dimensional measurement of flame radiation spectrum and intensity according to claim 1, characterized in that: The calibration device further comprises a baffle (14); the baffle (14) is arranged between the halogen tungsten lamp and the second optical fiber (6); a through hole is provided on the baffle (14), and the light path received by the second optical fiber (6) passes through the through hole.

6. The experimental system for three-dimensional measurement of flame radiation spectrum and intensity according to claim 5, characterized in that: The calibration device further comprises a black plate (15); the black plate (15) is perpendicular to a reverse extension line of the light path received by the second optical fiber (6).

7. The experimental system for three-dimensional measurement of flame radiation spectrum and intensity according to claim 6, characterized in that: The distance between the black plate (15) and the halogen tungsten lamp is twice the distance between the halogen tungsten lamp and the second optical fiber.

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