A visual analysis method and system for chemical reaction flow field

Abstract

The present invention provides a method and system for visual analysis of a chemical reaction flow field, the method comprising: using a standard black body furnace to calibrate the response of an RGB camera and a high-speed camera at a wavelength corresponding to a measurement target; using an RGB camera and a high-speed camera equipped with a filter for the wavelength corresponding to the measurement target to collect images of the target chemical reaction flow field; fitting the gray body radiation curve of the target chemical reaction flow field according to the response of the RGB camera and the collected image of the target chemical reaction flow field, combining the response of the high-speed camera at the wavelength corresponding to the measurement target, obtaining a theoretical gray body radiation image at the wavelength corresponding to the measurement target, and filtering out the high-temperature solid radiation interference at the wavelength corresponding to the measurement target in the target chemical reaction flow field through spectral processing and digital image processing based on the image at the wavelength corresponding to the measurement target. The present invention also provides a system based on the above method, which solves the problem in the prior art that gray body radiation cannot be filtered out in the visualization image of the chemical reaction flow field.

Description

Technical Field

[0001] The present invention relates to the field of fluid mechanics, and in particular to a visualization analysis method and system for a chemical reaction flow field. Background Art

[0002] In high-enthalpy wind tunnels, aerospace engines and other equipment, the visualization of chemical reaction flow fields is of great significance for understanding the dynamics of chemical reaction flow fields. The currently widely used chemical reaction flow field visualization method usually opens a window in the target field, and then directly uses a high-speed camera combined with a filter to collect a specific chemiluminescent component, such as CH*, OH*, etc.

[0003] However, since the flow fields of high-enthalpy wind tunnels, aerospace engines, etc. often contain a large number of high-temperature solid particles, they will have a significant impact on the radiation signal of the gas component. For example, the gray body radiation caused by the high-temperature boundary layer of the high-enthalpy wind tunnel flow field and the gray body radiation caused by the incompletely atomized and pyrolyzed fuel in the engine combustion field will affect the radiation signal of the gas component. Therefore, due to the influence of solid particles, the images obtained by the currently commonly used chemical reaction flow field visualization method are inaccurate due to the presence of gray body radiation, and thus cannot correctly reflect the flow characteristics of the target flow field. Summary of the invention

[0004] The present invention provides a visualization analysis method and system for a chemical reaction flow field, so as to solve the problem in the prior art that gray body radiation cannot be filtered out in a visualization image of a chemical reaction flow field.

[0005] In a first aspect of the present invention, a method for visualizing and analyzing a chemical reaction flow field is provided, comprising:

[0006] Use a standard blackbody furnace to calibrate the response of the RGB camera and high-speed camera at the wavelength corresponding to the measurement target;

[0007] Use the RGB camera and the high-speed camera equipped with a wavelength filter corresponding to the measurement target to collect images of the target chemical reaction flow field;

[0008] According to the response of the RGB camera and the collected image of the target chemical reaction flow field, the gray body radiation curve of the target chemical reaction flow field is fitted, and combined with the response of the high-speed camera at the wavelength corresponding to the measurement target, a theoretical gray body radiation image at the wavelength corresponding to the measurement target is obtained. Based on the image at the wavelength corresponding to the measurement target, high-temperature solid radiation interference at the wavelength corresponding to the measurement target in the target chemical reaction flow field is filtered out through spectral processing and digital image processing.

[0009] Furthermore, the measurement targets include chemiluminescent components in combustion and spontaneous emission components of gas in high-temperature flow.

[0010] Furthermore, a method for calibrating the response is also included:

[0011] Using the high-speed camera to image the standard black body furnace at a wavelength corresponding to a measurement target, and using the RGB camera to image the standard black body furnace, wherein three channels of the RGB camera correspond to three response wavelengths;

[0012] The pixel values ​​of the three channels of the image obtained by the RGB camera and the pixel values ​​of the image obtained by the high-speed camera are respectively divided by the radiation intensity of the standard gray body at the corresponding wavelength to calibrate the response of the RGB camera and the high-speed camera at the corresponding wavelength.

[0013] Furthermore, the process of fitting the gray body radiation curve of the target chemical reaction flow field is:

[0014] The pixel values ​​of the three channels of the image obtained by the RGB camera are divided by the response of the RGB camera at the corresponding wavelengths to obtain the gray body radiation intensity of the target chemical reaction flow field at the wavelengths corresponding to the three channels;

[0015] The obtained grey body radiation intensities at three wavelengths are used to fit the grey body radiation curve of the target chemical reaction flow field.

[0016] Furthermore, after fitting the gray body radiation curve of the target chemical reaction flow field, the method further includes: obtaining the radiation intensity at the wavelength corresponding to the measurement target according to the fitted gray body radiation curve of the target chemical reaction flow field and in combination with the wavelength corresponding to the measurement target;

[0017] The theoretical gray body radiation image of the target chemical reaction flow field at the wavelength corresponding to the measurement target is obtained by multiplying the radiation intensity at the wavelength corresponding to the measurement target by the response of the high-speed camera at the wavelength corresponding to the measurement target;

[0018] The theoretical grey body radiation image is deducted from the image of the measurement target at the corresponding wavelength collected by the high-speed camera to obtain the target flow field image without grey body radiation.

[0019] Furthermore, the RGB camera and the high-speed camera are synchronously triggered with an ignition signal of the target chemical reaction flow field.

[0020] In a second aspect of the present invention, a system based on the above-mentioned visualization analysis method of chemical reaction flow field is provided, comprising:

[0021] Target chemical reaction flow field, in which measurement targets are generated in the internal flow field, including chemiluminescent components in combustion or spontaneous emission components of gas in high-temperature flow;

[0022] An RGB camera collects images in the target chemical reaction flow field through an optical path;

[0023] A high-speed camera collects images in the target chemical reaction flow field through a filter and the same optical path as the RGB;

[0024] A standard black body furnace, which assists the RGB camera and the high-speed camera in calibrating the responses of the RGB camera and the high-speed camera at a wavelength corresponding to a measurement target;

[0025] an image fitting module, connected to the RGB camera and the high-speed camera, and fitting a gray body radiation curve of the target chemical reaction flow field based on the response of the RGB camera at a corresponding wavelength;

[0026] The image processing module is connected to the image fitting module, obtains the radiation intensity at the corresponding wavelength of the measurement target according to the fitted gray body radiation curve of the target chemical reaction flow field, performs image processing on the image at the corresponding wavelength of the measurement target collected by the high-speed camera, and obtains the image at the corresponding wavelength of the measurement target in the target chemical reaction flow field without gray body radiation.

[0027] Furthermore, the response wavelengths of the three channels of the RGB camera are 450, 550 and 650 nm, and only the gray body radiation signal is transmitted.

[0028] Furthermore, the acquisition frequencies of the RGB camera and the high-speed camera are both 1 kHz, and the exposure times are both 1 ms.

[0029] Furthermore, the target chemical reaction flow field is a wind tunnel or an aerospace engine.

[0030] Compared with the prior art, the present invention has the following beneficial effects: in the present invention, by using an RGB camera to image a standard blackbody furnace, the response of the RGB camera at its three-channel response wavelength can be calibrated, and combined with the collected image of the target chemical reaction flow field, the gray body radiation curve of the target chemical reaction flow field can be fitted, and combined with the response of the high-speed camera at the corresponding wavelength of the measurement target, the theoretical gray body radiation image at the corresponding wavelength of the measurement target can be obtained, and based on the image at the corresponding wavelength of the measurement target, through spectral processing and digital image processing, the gray body radiation interference in the radiation of the corresponding wavelength of the measurement target collected by the high-speed camera is filtered. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] 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.

[0032] Figure 1 It is a flow chart of the visualization analysis method of the chemical reaction flow field in an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of using a standard blackbody furnace to perform response calibration in an embodiment of the present invention;

[0034] Figure 3 A schematic diagram of collecting a target flow field according to an embodiment of the present invention;

[0035] Numbers in the figure:

[0036] 1-RGB camera, 2-high-speed camera, 3-standard blackbody furnace, 4-target flow field. DETAILED DESCRIPTION

[0037] 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.

[0038] like Figure 1 As shown, the present invention provides a visualization analysis method for a chemical reaction flow field, comprising:

[0039] Use a standard blackbody furnace to calibrate the response of the RGB camera and high-speed camera at the wavelength corresponding to the measurement target;

[0040] Use the RGB camera and the high-speed camera equipped with a wavelength filter corresponding to the measurement target to collect images of the target chemical reaction flow field;

[0041] According to the response of the RGB camera and the collected image of the target chemical reaction flow field, the gray body radiation curve of the target chemical reaction flow field is fitted, and combined with the response of the high-speed camera at the wavelength corresponding to the measurement target, a theoretical gray body radiation image at the wavelength corresponding to the measurement target is obtained. Based on the image at the wavelength corresponding to the measurement target, high-temperature solid radiation interference at the wavelength corresponding to the measurement target in the target chemical reaction flow field is filtered out through spectral processing and digital image processing.

[0042] In the present invention, the measurement targets include chemiluminescent components in combustion and spontaneous emission components of gases in high-temperature flows. This method can be used to filter out high-temperature solid radiation interference, such as gray body radiation, at the wavelength of the chemiluminescent components or spontaneous emission components of gases in the visualization image of the target chemical reaction flow field.

[0043] In a possible embodiment, the process of the visual parsing method is:

[0044] First, the high-speed camera is used to image the standard black body furnace at a wavelength corresponding to the measurement target, and the RGB camera is used to image the standard black body furnace, wherein the three channels of the RGB camera correspond to three wavelengths;

[0045] Dividing the pixel values ​​of the three channels of the image obtained by the RGB camera and the pixel values ​​of the image obtained by the high-speed camera by the radiation intensity of the standard gray body at the corresponding wavelength, respectively, to calibrate the response of the RGB camera and the high-speed camera at the corresponding wavelength;

[0046] The pixel values ​​of the three channels of the image obtained by the RGB camera are divided by the response of the RGB camera at the corresponding wavelengths to obtain the gray body radiation intensity of the target chemical reaction flow field at the wavelengths corresponding to the three channels;

[0047] Using the obtained gray body radiation intensities at three wavelengths, fitting the gray body radiation curve of the target chemical reaction flow field;

[0048] According to the fitted gray body radiation curve of the target chemical reaction flow field, combined with the corresponding wavelength of the measurement target, the radiation intensity at the corresponding wavelength of the measurement target is obtained;

[0049] The theoretical gray body radiation image of the target chemical reaction flow field at the wavelength corresponding to the measurement target is obtained by multiplying the radiation intensity at the wavelength corresponding to the measurement target by the response of the high-speed camera at the wavelength corresponding to the measurement target;

[0050] The theoretical grey body radiation image is deducted from the image of the measurement target at the corresponding wavelength collected by the high-speed camera to obtain the target flow field image without grey body radiation.

[0051] It should be noted that the RGB camera and the high-speed camera are triggered synchronously with the ignition signal of the target chemical reaction flow field, so that the RGB camera and the high-speed camera measure the image information in the target flow field while the target flow field undergoes a chemical reaction.

[0052] In a second aspect of the present invention, a system based on the above-mentioned visualization analysis method of chemical reaction flow field is also provided, comprising:

[0053] An RGB camera collects images in the target chemical reaction flow field through an optical path;

[0054] A high-speed camera collects images in the target chemical reaction flow field through a filter and the same optical path as the RGB;

[0055] The standard black body furnace assists the RGB camera and the high-speed camera to calibrate the response of the RGB camera and the high-speed camera at the wavelength corresponding to the measurement target, such as Figure 2 As shown;

[0056] Target chemical reaction flow field, the internal flow field generates measurement targets, including chemiluminescent components in combustion or spontaneous emission components of gas in high temperature flow, such as Figure 3 As shown;

[0057] an image fitting module, connected to the RGB camera and the high-speed camera, and fitting a gray body radiation curve of the target chemical reaction flow field based on the response of the RGB camera at a corresponding wavelength;

[0058] The image processing module is connected to the image fitting module, obtains the radiation intensity at the corresponding wavelength of the measurement target according to the fitted gray body radiation curve of the target chemical reaction flow field, performs image processing on the image at the corresponding wavelength of the measurement target collected by the high-speed camera, and obtains the image at the corresponding wavelength of the measurement target in the target chemical reaction flow field without gray body radiation.

[0059] In the present invention, the central wavelength of the filter is related to the wavelength corresponding to the measurement target, which is the chemiluminescent components such as OH*, CH*, etc. in hydrocarbon fuels, and the spontaneous radiation of gases such as N2, 710-770nm broadband radiation in high temperature flows.

[0060] In a possible embodiment, the filter has a diameter of 25.4 mm, a central wavelength of 310 nm, and a bandwidth of 10 nm. It can be clamped in a high-speed camera and transmits OH* signals and gray body radiation. The response wavelengths of the three channels of the RGB camera are 450, 550, and 650 nm, and only the gray body radiation signal is transmitted.

[0061] The acquisition frequencies of the RGB camera and the high-speed camera are both 1 kHz, and the exposure times are both 1 ms.

[0062] The target chemical reaction flow field is a wind tunnel or an aerospace engine, and its gray body radiation source is metal dust in the wind tunnel, solid particles produced by combustion, etc. The optical path is a beam-combined imaging fiber, and the camera collects images in the target chemical reaction flow field through the beam-combined imaging fiber.

[0063] The method and system provided by the present invention can effectively overcome the interference of high-temperature solid radiation such as particles and dust in the target flow field imaging, obtain the true flow field radiation characteristics, and help improve the understanding of complex flows involving chemical reactions.

[0064] In a specific embodiment, the filter corresponding to the wavelength of the measurement target needs to be customized to be installed in the high-speed camera, and its central wavelength can be selected to correspond to a chemiluminescent substance (such as OH* corresponding to 310nm), which is recorded as wavelength 1. The response wavelengths of the three channels of the RGB camera are recorded as wavelength 2, wavelength 3 and wavelength 4. The specific process is:

[0065] (1) Before the experiment, the radiation intensity of the gray body at these four wavelengths was obtained from the standard gray body radiation curve.

[0066] (2) Using an RGB camera, a filter, and a high-speed camera, the standard blackbody furnace is imaged at corresponding wavelengths, that is, the high-speed camera is imaged at wavelength 1, and the RGB camera is imaged at wavelengths 2, 3, and 4.

[0067] (3) The pixel values ​​of the three channels of the image obtained using RGB and the pixel values ​​of the high-speed camera image are divided by the radiation intensity of the standard gray body at the corresponding wavelength to obtain the camera's response 1, response 2, response 3 and response 4 at the four wavelengths.

[0068] (4) During the experiment, the RGB camera and the high-speed camera equipped with the wavelength filter corresponding to the measurement target are aimed at the same target chemical reaction flow field area, and the RGB camera and the high-speed camera are triggered synchronously to collect images of the target chemical reaction flow field at wavelengths 1, 2, 3, and 4 (i.e., the high-speed camera collects images at wavelength 1, and the RGB camera collects images at wavelengths 2, 3, and 4).

[0069] The image obtained at wavelength 1 contains gas radiation luminescence or chemiluminescence signals and gray body radiation, and the images obtained at wavelengths 2, 3 and 4 contain only gray body radiation.

[0070] (5) Divide the pixel values ​​of image 2, image 3 and image 4 by response 2, response 3 and response 4 to obtain the gray body radiation intensity 2, intensity 3 and intensity 4 of the target flow field at wavelength 2, wavelength 3 and wavelength 4.

[0071] (6) The theoretical gray body radiation curve of the target flow field is fitted based on the calculated gray body radiation intensity 2, radiation intensity 3, and radiation intensity 4, thereby obtaining the radiation intensity 1 of the target flow field at wavelength 1.

[0072] (7) The radiation intensity 1 of the target flow field at wavelength 1 is multiplied by the response 1 to obtain the theoretical gray body radiation image 1' of the target flow field at wavelength 1.

[0073] (8) Subtract the theoretical gray body image 1' from the image 1 to filter out the radiation interference of solid particles in the collected image at the corresponding wavelength of the measurement target in the flow field, such as high-temperature solid radiation interference of particles, dust, etc., so as to extract the dynamic information of spontaneous radiation / chemiluminescence of the gas components in the flow field.

[0074] 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. A visual analysis method for a chemical reaction flow field, characterized in that: include: Use a standard blackbody furnace to calibrate the response of the RGB camera and high-speed camera at the wavelength corresponding to the measurement target; Use the RGB camera and the high-speed camera equipped with a wavelength filter corresponding to the measurement target to collect images of the target chemical reaction flow field; According to the response of the RGB camera and the collected image of the target chemical reaction flow field, the pixel values ​​of the three channels of the image obtained by the RGB camera are divided by the response of the RGB camera at the corresponding wavelength to obtain the gray body radiation intensity of the target chemical reaction flow field at the wavelengths corresponding to the three channels; Using the obtained gray body radiation intensities at three wavelengths, fitting the gray body radiation curve of the target chemical reaction flow field; According to the fitted gray body radiation curve of the target chemical reaction flow field, combined with the corresponding wavelength of the measurement target, the radiation intensity at the corresponding wavelength of the measurement target is obtained; The theoretical gray body radiation image of the target chemical reaction flow field at the wavelength corresponding to the measurement target is obtained by multiplying the radiation intensity at the wavelength corresponding to the measurement target by the response of the high-speed camera at the wavelength corresponding to the measurement target. Based on the image at the wavelength corresponding to the measurement target, the high-temperature solid radiation interference at the wavelength corresponding to the measurement target in the target chemical reaction flow field is filtered out through spectral processing and digital image processing.

2. A method for visual analysis of a chemical reaction flow field according to claim 1, characterized in that: The measurement targets include chemiluminescent components in combustion and spontaneous emission components of gas in high-temperature flow.

3. A method for visual analysis of a chemical reaction flow field according to claim 1 or 2, characterized in that: Also included are methods for calibrating responses: Using the high-speed camera to image the standard black body furnace at a wavelength corresponding to a measurement target, and using the RGB camera to image the standard black body furnace, wherein three channels of the RGB camera correspond to three response wavelengths; The pixel values ​​of the three channels of the image obtained by the RGB camera and the pixel values ​​of the image obtained by the high-speed camera are respectively divided by the radiation intensity of the standard gray body at the corresponding wavelength to calibrate the response of the RGB camera and the high-speed camera at the corresponding wavelength.

4. The method for visual analysis of a chemical reaction flow field according to claim 1, characterized in that: The RGB camera and the high-speed camera are synchronously triggered with the ignition signal of the target chemical reaction flow field.

5. A system based on the visualization analysis method of chemical reaction flow field according to any one of claims 1 to 4, characterized in that: include: Target chemical reaction flow field, in which measurement targets are generated in the internal flow field, including chemiluminescent components in combustion or spontaneous emission components of gas in high-temperature flow; An RGB camera collects images in the target chemical reaction flow field through an optical path; A high-speed camera collects images in the target chemical reaction flow field through a filter and the same optical path as the RGB; A standard black body furnace, which assists the RGB camera and the high-speed camera in calibrating the responses of the RGB camera and the high-speed camera at a wavelength corresponding to a measurement target; an image fitting module, connected to the RGB camera and the high-speed camera, and fitting a gray body radiation curve of the target chemical reaction flow field based on the response of the RGB camera at a corresponding wavelength; The image processing module is connected to the image fitting module, obtains the radiation intensity at the corresponding wavelength of the measurement target according to the fitted gray body radiation curve of the target chemical reaction flow field, performs image processing on the image at the corresponding wavelength of the measurement target collected by the high-speed camera, and obtains the image at the corresponding wavelength of the measurement target in the target chemical reaction flow field without gray body radiation.

6. The system according to claim 5, characterized in that The response wavelengths of the three channels of the RGB camera are 450, 550 and 650 nm, and only the gray body radiation signal is transmitted.

7. The system according to claim 5, characterized in that The acquisition frequencies of the RGB camera and the high-speed camera are both 1 kHz, and the exposure times are both 1 ms.

8. The system according to claim 5, characterized in that The target chemical reaction flow field is a wind tunnel or an aerospace engine.

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