A spatially resolved combustion flow field sensing and measuring device and method

Abstract

A spatially resolved combustion flow field sensing and measuring device and method, belonging to the field of spectral measurement technology. Imaging lenses one and two, fiber collimators, beam splitters, filters, photomultiplier tubes, spectrometers, and timing control systems can all be detachably mounted on a two-dimensional movable optical plate. Imaging lens one is placed in front of the combustion flow field to be measured, one end of the imaging optical fiber is connected to the imaging focal plane of imaging lens one, and the other end is connected to the fiber collimator; the beam splitter cube, filter, and photomultiplier tube are placed from front to back directly behind the fiber collimator, and the fiber collimator is parallel to the two opposite end faces of the beam splitter cube; the spectrometer and imaging lens two are both placed on the emission light path of the beam splitter cube, and the imaging lens two is placed between the beam splitter cube and the spectrometer; the spectrometer and the photomultiplier tube are both connected to the timing control system signal, and the spectrometer and the photomultiplier tube work simultaneously by controlling the synchronization signal of the timing control system. The present invention is used for combustion flow field sensing and measurement.

Description

Technical Field

[0001] The invention relates to a spatially resolved combustion flow field sensing measurement device and method, belonging to the technical field of spectral measurement. Background Art

[0002] Combustion flow field sensing measurements are essential for understanding and controlling the combustion process, especially in industrial applications and scientific research. Combustion flow field sensing involves measuring and analyzing multiple parameters in the combustion process, including temperature, pressure, chemical composition, flow rate, and turbulence characteristics. This information is essential for optimizing combustion efficiency, reducing pollutant emissions, ensuring safe operation, and improving fuel efficiency.

[0003] Perception measurement can improve the understanding of the combustion flow field by obtaining the temperature and component concentration of flame combustion. The temperature measurement of the flame is of great significance for the control and research of the combustion process. By measuring the flame temperature, the combustion efficiency can be evaluated and combustion diagnosis can be performed. At the same time, adjusting the combustion conditions according to the flame temperature can reduce the emission of harmful gases such as nitrogen oxides. The concentration of components in the flame helps to evaluate the combustion efficiency of the fuel, better understand the combustion kinetics and chemical reaction mechanism, and also identify the combustion process.

[0004] Traditional measurement and perception methods have limited resolution. When using thermocouples or probes for measurement, the structure of the flow field will be disturbed. The measurement parameters are limited, and other important flow field information such as chemical composition is missing. At the same time, measurements are generally performed at fixed positions, and the range of flow field information obtained is limited. Summary of the invention

[0005] The purpose of the present invention is to provide a spatially resolved combustion flow field sensing measurement device and method, which can realize the synchronous measurement of the flame temperature and the concentration of a certain component under different combustion conditions, and can analyze the combustion state through temperature and component concentration.

[0006] The measurement method of the present invention is an optical measurement method, which can solve the problem of insufficient resolution of traditional measurement and perception methods. It uses the acquisition of spectrum and light intensity to perceive the information of the flow field (the combustion flow field to be measured), and can obtain information on temperature and component concentration. It uses emission spectrum and photomultiplier tube to realize synchronous measurement and perception of flame temperature and components, and uses imaging optical fiber to ensure that the measuring device has the ability of spatial resolution.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] A spatially resolved combustion flow field sensing and measuring device comprises an imaging lens 1, an imaging lens 2, an imaging optical fiber, an optical fiber collimator, a beam splitter cube, an optical filter, a photomultiplier tube, a spectrometer, a timing control system and a two-dimensional movable optical plate;

[0009] Imaging lens 1, imaging lens 2, fiber collimator, beam splitter cube, filter, photomultiplier tube, spectrometer, and timing control system can all be detachably mounted on a two-dimensional movable optical plate. Imaging lens 1 is placed in front of the combustion flow field to be measured, one end of the imaging fiber is connected to the imaging focal plane of imaging lens 1, and the other end of the imaging fiber is connected to the fiber collimator; the beam splitter cube, filter, and photomultiplier tube are placed in sequence from front to back directly behind the fiber collimator, and the fiber collimator is parallel to the two opposite end faces of the beam splitter cube; the spectrometer and imaging lens 2 are both placed on the emission light path of the beam splitter cube, and the imaging lens 2 is placed between the beam splitter cube and the spectrometer; the spectrometer and the photomultiplier tube are both connected to the timing control system signal, and the spectrometer and the photomultiplier tube work simultaneously by controlling the synchronization signal of the timing control system.

[0010] Furthermore, when the measured component is OH, the imaging lens 1 is a quartz UV lens, and the imaging optical fiber is a UV fused silica optical fiber.

[0011] A spatially resolved combustion flow field sensing and measuring method is implemented by using a spatially resolved combustion flow field sensing and measuring device, and the method comprises the following steps:

[0012] Step 1: placing the imaging lens 1 of the measuring device in front of the combustion flow field to be measured, and after the imaging lens 1 determines the imaging position, using the imaging lens 1 to image the flame of the combustion flow field to be measured, and transmitting it to the optical fiber collimator for collimation through the imaging optical fiber;

[0013] Step 2: After the collimated image is split by the beam splitter cube, 50% of the light is transmitted by the filter, and the component concentration of the transmitted light is measured using a photomultiplier tube to obtain the signal intensity of the measured component; the remaining 50% of the light is reflected and imaged by the second imaging lens, and the emission spectrum of the image is measured by a spectrometer to obtain the emission spectrum of the flame; the entire measurement process is controlled by the synchronization signal in the timing control system to ensure that the photomultiplier tube measurement and the spectrometer measurement are performed at the same time, thereby obtaining the emission spectrum and the signal intensity of the measured component at the same time;

[0014] Step 3: Based on the emission spectrum temperature measurement principle, the absolute temperature T distribution of the flame is obtained according to formula (1); since the photomultiplier tube signal is proportional to the light intensity, the relative or absolute component concentration is obtained according to the needs;

[0015]

[0016] Among them: I1 and I2 represent the intensity of the emission lines at two different energy levels, g1 and g2 represent the statistical weights corresponding to the two different energy levels, A1 and A2 represent the Einstein transition probability coefficients corresponding to the two different energy levels, and E1 and E2 represent the energies corresponding to the two different energy levels;

[0017] Step 4: Flow field information perception

[0018] Imaging lens 1 and imaging lens 2 are used to realize measurement at different spatial positions, and the absolute temperature and component concentration are obtained with spatial resolution. The measured temperature and component concentration sense the information of the flow field. By moving the two-dimensional movable optical plate, information acquisition at different positions is realized, and information perception is realized by analyzing the flow field characteristics at different position spaces.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] Imaging lens 1 is used to image the flame of the combustion flow field to be measured. After determining the imaging position, the imaging optical fiber is used to transmit the image formed by imaging lens 1, which is collimated by the optical fiber collimator. After the collimated image passes through the beam splitter cube, 50% of the light is transmitted, and the transmitted light is detected by the photomultiplier tube after passing through the filter that obtains the corresponding component signal. Different filters detect different components; 50% of the light is reflected, and the reflected light is detected by the spectrometer through imaging lens 2, and the emission spectrum of the flame can be obtained. The entire measuring device is controlled by the synchronous signal in the timing control system, ensuring that the detection spectrum and the photomultiplier tube detection are carried out at the same time. Since the imaging optical fiber images a certain area, it has the characteristics of spatial resolution. All equipment is placed on a two-dimensionally movable optical plate. By adjusting the position of the optical plate, the temperature and component concentration of different areas can be obtained, and then the flow field information can be perceived.

[0021] The device and method of the present invention can optimize combustion efficiency, control emissions, ensure safe operation, improve product quality, and promote scientific research and innovation by sensing and measuring the combustion flow field to be measured. Accurate measurement results can help us better understand and control the combustion process, achieve efficient use of energy and sustainable development of the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of a spatially resolved combustion flow field sensing and measuring device of the present invention.

[0023] The names and reference numerals of the components involved in the above drawings are as follows:

[0024] Imaging lens 1, imaging lens 2, imaging optical fiber, optical fiber collimator, beam splitter cube, optical filter, photomultiplier tube, spectrometer, timing control system, and two-dimensional movable optical plate. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] Specific implementation method 1: Figure 1 As shown, this embodiment describes a spatially resolved combustion flow field sensing and measuring device, including an imaging lens 1, an imaging lens 2, an imaging optical fiber 3, an optical fiber collimator 4, a beam splitter cube 5, a filter 6, a photomultiplier tube 7, a spectrometer 8, a timing control system 9 and a two-dimensional movable optical plate 10;

[0027] Imaging lens 1, imaging lens 2, fiber collimator 4, beam splitter cube 5, filter 6, photomultiplier tube 7, spectrometer 8, and timing control system 9 are all detachably mounted on a two-dimensional movable optical plate 10 (the prior art). Imaging lens 1 is placed in front of the combustion flow field to be measured, one end of the imaging fiber 3 is connected to the imaging focal plane of the imaging lens 1 (the focal length of the imaging lens 1 is determined according to the distance between the imaging lens 1 and the combustion flow field to be measured), and the other end of the imaging fiber 3 is connected to the fiber collimator 4; the beam splitter cube 5, filter 6 and photomultiplier tube 7 are placed in sequence from front to back directly behind the fiber collimator 4, and the fiber collimator The device 4 is parallel to the two opposite end faces of the beam splitter cube 5 (the beam splitter cube 5 is full-band intensity beam splitting. After the light passes through the beam splitter cube 5, 50% of the light is reflected and 50% of the light is transmitted. The reflected light is used to measure the flame emission spectrum, and the transmitted light is used to measure the flame component concentration); the spectrometer 8 and the imaging lens 2 are both placed on the emission light path of the beam splitter cube 5, and the imaging lens 2 is placed between the beam splitter cube 5 and the spectrometer 8; the spectrometer 8 and the photomultiplier tube 7 are both connected to the timing control system 9 by signal, and the spectrometer 8 and the photomultiplier tube 7 are made to work simultaneously by controlling the synchronization signal of the timing control system 9.

[0028] Furthermore, when the measured component is OH (the spectrum range of OH is around 315nm), the imaging lens 1 is a quartz UV lens, and the imaging optical fiber 3 is a UV fused silica optical fiber (that is, the selection of the imaging lens 1 and the imaging optical fiber 3 is determined according to the measured component).

[0029] Specific implementation method 2: Figure 1As shown, this embodiment describes a method for sensing and measuring a combustion flow field with spatial resolution, which is implemented using the measuring device described in the first embodiment, and includes the following steps:

[0030] Step 1: placing the imaging lens 1 of the measuring device in front of the combustion flow field to be measured, and after the imaging lens 1 determines the imaging position, using the imaging lens 1 to image the flame of the combustion flow field to be measured, and transmitting it to the optical fiber collimator 4 for collimation through the imaging optical fiber 3;

[0031] Step 2: After the collimated image is split by the beam splitter cube 5 (full-band intensity beam splitting), 50% of the light is transmitted by the filter 6 (different filters 6 detect different components), and the component concentration of the transmitted light is measured using the photomultiplier tube 7 to obtain the signal intensity of the measured component; the remaining 50% of the light is reflected, imaged by the imaging lens 2, and the emission spectrum of the image is measured by the spectrometer 8 to obtain the emission spectrum of the flame; the entire measurement process is controlled by the synchronization signal in the timing control system 9 to ensure that the measurement of the photomultiplier tube 7 and the measurement of the spectrometer 8 are performed at the same time, thereby obtaining the emission spectrum and the signal intensity of the measured component at the same time;

[0032] Step 3: According to the emission spectrum temperature measurement principle, the absolute temperature T distribution of the flame is obtained according to formula (1); since the signal of the photomultiplier tube 7 is proportional to the light intensity, the relative or absolute component concentration is obtained according to the needs;

[0033]

[0034] Among them: I1 and I2 represent the intensity of the emission lines at two different energy levels, g1 and g2 represent the statistical weights corresponding to the two different energy levels, A1 and A2 represent the Einstein transition probability coefficients corresponding to the two different energy levels, and E1 and E2 represent the energies corresponding to the two different energy levels;

[0035] Step 4: Flow field information perception

[0036] Imaging lens 1 and imaging lens 2 are used to realize measurement of different spatial positions, obtain absolute temperature and component concentration with spatial resolution characteristics, and sense flow field information by measuring temperature and component concentration. By moving the two-dimensional movable optical plate 10, information acquisition at different positions is realized, and information perception is realized by analyzing the flow field characteristics at different position spaces.

[0037] In the present invention, according to the requirements of imaging distance and spatial resolution, an imaging lens 1, an imaging lens 2, and an imaging optical fiber 3 with suitable focal length and aperture number are selected, and a filter 6 is selected according to the type of component to be measured.

[0038] In the present invention, by adjusting the position of the imaging lens 2, the distance between the imaging lens 2 and the spectrometer 8 is continuously changed, and the optimal position is selected according to the imaging distance between the imaging lens 2 and the combustion flow field, the focal length of the imaging distance and the requirements of spatial resolution, so as to ensure the imaging efficiency of the spectrometer 8 in the measurement process and improve the signal-to-noise ratio of the emission spectrum measurement.

[0039] In the present invention, by moving the position of the photomultiplier tube 7, it is ensured that the measurement position of the photomultiplier tube 7 is directly opposite to the beam splitting cube 5, thereby improving the measurement signal-to-noise ratio.

[0040] The photomultiplier tube 7 and the filter 6 are used to measure the concentration of the components. Different components use different filters 6. The function of the filter 6 is to ensure that the photomultiplier tube 7 only measures the required specific components and is not affected by other components.

[0041] The imaging lens 22 and the spectrometer 8 are used to measure the flame emission spectrum. The imaging lens 22 is used to transmit the signal to the spectrometer 8. The focal length of the imaging lens 22 is determined according to the positions of the beam splitter cube 5 and the spectrometer 8. After the spectrometer 8 measures the signal from the imaging lens 22, the spectrum given is used to calculate the flame temperature.

[0042] The signal output by the photomultiplier tube 7 is proportional to the intensity of the light signal to be measured. The intensity of the signal to be measured can be obtained based on the intensity. Without prior calibration, a relative concentration distribution can be obtained. After calibration measurement in a standard flame, the absolute concentration can be obtained.

[0043] When a substance is heated to a high enough temperature, its atoms gain energy and jump to a higher energy level. This process is called excitation. When these excited atoms return to a lower energy level, they emit light of a specific wavelength. The wavelength and intensity of this light depend on the type of atom and the temperature of the flame. When the atoms in the flame jump from a high energy level E2 to a low energy level E1, photons are emitted. The energy of these photons is E p It is equal to the energy difference between the two energy levels (high energy level E2 and low energy level E1). The emitted photon energy E p Expressed by formula (2):

[0044] E p =E2-E1 (2)

[0045] The emitted photon energy E p is related to the wavelength λ of the emitted light, and the relationship between the two is given by Planck's relation (3):

[0046]

[0047] Where: h is Planck's constant, ν is the frequency of photons, and c is the speed of light; flame temperature measurement is usually based on the Boltzmann distribution law. According to this law, at a temperature T, the ratio of the number of particles N at energy level E to the number of particles N0 at the ground state energy level E0 is given by the following formula (4):

[0048]

[0049] Where: g and g0 are the statistical weights of energy level E and ground state E0, respectively, referred to as degeneracy; k is the Boltzmann constant, and T is the absolute temperature. In flame emission spectrum temperature measurement, the above principle can be used to measure the intensity of a specific spectral line and calculate the temperature using formula (5):

[0050]

[0051] Among them: I1 and I2 represent the intensity of the emission lines at two different energy levels, g1 and g2 represent the statistical weights corresponding to the two different energy levels, A1 and A2 represent the Einstein transition probability coefficients corresponding to the two different energy levels, and E1 and E2 represent the energies corresponding to the two different energy levels.

[0052] By measuring the intensity ratio of different spectral lines through the spectrometer 8, the absolute temperature T of the flame can be calculated by formula (1);

[0053]

[0054] Example:

[0055] like Figure 1 As shown, a spatially resolved combustion flow field sensing measurement method is a method for synchronously measuring flame temperature and component concentration in a combustion flow field, and the method comprises the following steps:

[0056] S1: Building a synchronous measurement system

[0057] First, determine the conditions of the combustion flow field to be measured, select imaging lens 1, imaging lens 2, and imaging optical fiber 3 with appropriate focal length and aperture number according to the requirements of imaging distance and spatial resolution, and select filter 6 according to the type of component to be measured; place imaging lens 1 in front of the combustion flow field to be measured, fix imaging optical fiber 3 and optical fiber collimator 4, and use timing control system 9 to ensure time synchronization between temperature measurement and component concentration measurement; use spectrometer 8 to measure emission spectrum, and use photomultiplier tube 7 to measure component concentration; place filter 6 for obtaining corresponding component signal in front of photomultiplier tube 7 to ensure that specific component concentration is measured during the experiment.

[0058] S2: Building an emission spectrum measurement system

[0059] After the imaging optical fiber 3, the optical fiber collimator 4, the beam splitter cube 5, and the imaging lens 1 are fixed, the position of the imaging lens 2 2 is adjusted, the distance between the imaging lens 2 2 and the spectrometer 8 is continuously changed, and a position that can achieve spatial resolution and a high signal-to-noise ratio is selected to ensure the imaging efficiency of the spectrometer 8 during the measurement process and improve the signal-to-noise ratio of the emission spectrum measurement;

[0060] S3: Build component concentration measurement system

[0061] After fixing the imaging optical fiber 3, the optical fiber collimator 4, and the beam splitter cube 5, place the filter 6 and the photomultiplier tube 7, and move the position of the photomultiplier tube 7 to ensure that the detection position of the photomultiplier tube 7 is directly opposite to the beam splitter cube 5 to improve the measurement signal-to-noise ratio;

[0062] S4: Synchronous measurement of flame temperature and component concentration

[0063] By controlling the synchronization signal of the timing control system 9, the spectrometer 8 and the photomultiplier tube 7 are ensured to work simultaneously, and the emission spectrum and the intensity of the measured component at the same time are obtained. The emission spectrum is measured by the spectrometer 8, and the temperature distribution of the flame is obtained according to the emission spectrum temperature measurement principle and formula (1). Since the signal of the photomultiplier tube 7 is proportional to the light intensity, the relative or absolute component concentration can be obtained according to the demand;

[0064] Step 5: Flow field information perception

[0065] The temperature and component concentrations obtained have the characteristics of spatial resolution. The measured temperature and component concentrations perceive the information of the flow field. Through the two-dimensional movable optical plate 10, information acquisition at different positions can be achieved, and information perception can be achieved by analyzing the flow field characteristics at different position spaces.

[0066] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other forms of assembly without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and range of equivalents of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0067] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A spatially resolved combustion flow field sensing and measuring device, characterized in that: It includes an imaging lens 1 (1), an imaging lens 2 (2), an imaging optical fiber (3), an optical fiber collimator (4), a beam splitter cube (5), an optical filter (6), a photomultiplier tube (7), a spectrometer (8), a timing control system (9) and a two-dimensional movable optical plate (10); The imaging lens 1 (1), the imaging lens 2 (2), the optical fiber collimator (4), the beam splitter (5), the optical filter (6), the photomultiplier tube (7), the spectrometer (8), and the timing control system (9) are all detachably mounted on a two-dimensional movable optical plate (10). The imaging lens 1 (1) is placed in front of the combustion flow field to be measured. One end of the imaging optical fiber (3) is connected to the imaging focal plane of the imaging lens 1 (1), and the other end of the imaging optical fiber (3) is connected to the optical fiber collimator (4). The beam splitter (5), the optical filter (6), and the photomultiplier tube (7) are connected by The optical fiber collimator (4) is sequentially placed in sequence from front to back, and the optical fiber collimator (4) is parallel to two opposite end faces of the beam splitter cube (5); the spectrometer (8) and the second imaging lens (2) are both placed on the emission light path of the beam splitter cube (5), and the second imaging lens (2) is placed between the beam splitter cube (5) and the spectrometer (8); the spectrometer (8) and the photomultiplier tube (7) are both connected to the timing control system (9) by signal, and the spectrometer (8) and the photomultiplier tube (7) are operated simultaneously by controlling the synchronization signal of the timing control system (9).

2. A spatially resolved combustion flow field sensing and measuring device according to claim 1, characterized in that: When the component to be measured is OH, the imaging lens 1 (1) is a quartz ultraviolet lens, and the imaging optical fiber (3) is an ultraviolet fused silica optical fiber.

3. A spatially resolved combustion flow field sensing and measurement method, characterized in that: The method is implemented using the measuring device according to claim 1 or 2, and the method comprises the following steps: Step 1: placing the imaging lens 1 (1) of the measuring device in front of the combustion flow field to be measured, and after the imaging lens 1 (1) determines the imaging position, using the imaging lens 1 (1) to image the flame of the combustion flow field to be measured, and transmitting the image to the optical fiber collimator (4) through the imaging optical fiber (3) for collimation; Step 2: After the collimated image is split by the beam splitter cube (5), 50% of the light is transmitted by the filter (6), and the component concentration of the transmitted light is measured using a photomultiplier tube (7) to obtain the signal intensity of the measured component; the remaining 50% of the light is reflected and imaged by the second imaging lens (2), and the emission spectrum of the image is measured by a spectrometer (8) to obtain the emission spectrum of the flame; the entire measurement process is controlled by a synchronization signal in a timing control system (9) to ensure that the photomultiplier tube (7) measurement and the spectrometer (8) measurement are performed at the same time, thereby obtaining the emission spectrum and the signal intensity of the measured component at the same time; Step 3: Based on the emission spectrum temperature measurement principle, the absolute temperature T distribution of the flame is obtained according to formula (1); since the photomultiplier tube (7) signal is proportional to the light intensity, the relative or absolute component concentration is obtained according to the requirements; Where: I1 and I2 represent the intensity of the emission lines at two different energy levels, g1 and g2 represent the statistical weights corresponding to the two different energy levels, A1 and A2 represent the Einstein transition probability coefficients corresponding to the two different energy levels, E1 and E2 represent the energies corresponding to the two different energy levels, and k is the Boltzmann constant; Step 4: Flow field information perception The imaging lens 1 (1) and the imaging lens 2 (2) are used to measure different spatial positions, obtain absolute temperature and component concentration with spatial resolution characteristics, and sense flow field information by measuring temperature and component concentration. By moving a two-dimensional movable optical plate (10), information acquisition at different positions is achieved, and information perception is achieved by analyzing flow field characteristics at different position spaces.

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