Dynamic identification and tracking method for spatial measurement position of ablation boundary layer

Abstract

The invention provides a dynamic identification and tracking method for a spatial measurement position of an ablation boundary layer. The method comprises the following steps: (1) firstly arranging an optical dynamic measurement system of the ablation boundary layer; (2) acquiring emission spectrum information of the ablation boundary layer of the heat-proof material through an optical dynamic measurement system of the ablation boundary layer, and determining main radiation components and wavelengths in the ablation boundary layer of the heat-proof material by analyzing the obtained emission spectrum information; and (3) acquiring radiation images of the heat-proof material and a surrounding flow field through an ablation boundary layer optical dynamic measurement system, reading and processing each frame of radiation image in real time to obtain position change information of the ablation boundary layer of the heat-proof material, and dynamically measuring parameters of a required spatial position in the ablation boundary layer in real time. And finally realizing dynamic identification and tracking of the space measurement position of the ablation boundary layer. The method is reasonable in conception, can accurately analyze the gas-solid coupling effect in the boundary layer, and is suitable for popularization and application.

Description

Technical Field

[0001] The present invention relates to the technical field of aerodynamic thermal protection of hypersonic aircraft, and in particular to a method for dynamically identifying and tracking a measurement position of an ablation boundary layer space. Background Art

[0002] Hypersonic vehicles face extreme thermal environments when flying in the atmosphere, and thermal protection systems play a key protective role at this time. Thermal protection materials must not only withstand high temperatures, but also deal with complex chemical reactions in the boundary layer that interact with the surrounding high-enthalpy non-equilibrium gases, such as catalysis, oxidation, and ablation. These processes are made more complicated by the gas-solid coupling effect. In this regard, optical-based non-invasive diagnostic methods, such as tunable semiconductor laser absorption spectroscopy (TDLAS), optical emission spectroscopy (OES), laser induced fluorescence (LIF), etc., can measure key parameters without interfering with the flow field, which helps to analyze the multi-process coupling mechanism in the boundary layer and provide important scientific basis and reference for the development of aircraft thermal protection technology.

[0003] S. Fang et al. explored the gas-solid coupling interface evolution of a carbon / carbon composite under high-enthalpy, nonequilibrium flow by optical diagnostic technology, and measured the translational temperature and number density of O atoms at different axial positions (0, 1, 2 mm) on the surface of the material using TDLAS. The results showed that there were significant differences in the measurement results at these positions, indicating that there were fine chemical reaction areas in the boundary layer on the surface of the heat-resistant material, so it was necessary to reflect the interaction mechanism in the boundary layer by measuring parameters at different spatial positions. However, a large number of related studies, including S. Fang, pointed out that heat-resistant materials will undergo ablation deformation during thermal assessment, causing surface expansion or retreat, which in turn drives the movement of the ablation boundary layer, and the original measurement points may not accurately reflect the actual boundary layer parameters. Therefore, it is necessary to develop a method that can dynamically track the ablation boundary layer to accurately characterize the gas-solid coupling effect in the boundary layer.

[0004] Since the ablation boundary layer appears at the place where the material surface reacts with the incoming gas, tracking the position of the material surface becomes an effective way to identify the dynamic changes of the ablation boundary layer. Image processing technology provides a solution for this. For example, Fagnani demonstrated in his work (3D infrared temperature maps measurements of ablative materialsduring plasma wind tunnel experiments), a research method that uses imaging combined with image processing methods such as edge detection and three-dimensional reconstruction to track the ablation behavior of heat-resistant materials during experiments. However, it is worth noting that this type of method still faces challenges when applied to thermal assessment experiments of heat-resistant materials: imaging blur caused by strong radiation increases the difficulty of data processing; determining the range of the ablation boundary layer is challenging; and most image processing methods only support post-offline analysis and cannot achieve real-time monitoring and adjustment.

[0005] In summary, the existing optical-based boundary layer parameter measurement method for thermal protection materials is difficult to cope with the dynamic changes of the ablation boundary layer, so it is necessary to further innovate the existing technology. Summary of the invention

[0006] In response to the technical problems existing in the above-mentioned background technology, the present invention proposes a method for dynamic identification and tracking of the spatial measurement position of the ablation boundary layer. The method has a reasonable concept and can accurately analyze the gas-solid coupling effect in the boundary layer, thus overcoming the problem that existing optical means are difficult to adapt to the dynamic changes of the ablation boundary layer when measuring the boundary layer parameters of heat-resistant materials.

[0007] In order to solve the above technical problems, the present invention provides a method for dynamically identifying and tracking the spatial measurement position of the ablation boundary layer, which comprises the following steps:

[0008] (1) First, deploy an optical dynamic measurement system for the ablation boundary layer for dynamic identification and tracking of the spatial measurement position of the ablation boundary layer;

[0009] (2) collecting emission spectrum information of the ablation boundary layer of the heat protection material by using the ablation boundary layer optical dynamic measurement system arranged in step (1), and determining the main radiation components and wavelengths in the ablation boundary layer of the heat protection material used by analyzing the obtained emission spectrum information;

[0010] (3) Then, the ablation boundary layer optical dynamic measurement system deployed in step (1) collects the radiation image of the heat-resistant material and the flow field around it, reads and processes each frame of the radiation image in real time to obtain the position change information of the ablation boundary layer of the heat-resistant material, and then dynamically measures the parameters of the required spatial position in the ablation boundary layer in real time, and finally realizes the dynamic identification and tracking of the spatial measurement position of the ablation boundary layer.

[0011] The method for dynamic identification and tracking of the spatial measurement position of the ablation boundary layer, wherein: the optical dynamic measurement system of the ablation boundary layer in step (1) comprises a plasma device, a linear servo motor translation stage, an optical measurement device, a computer, a high-speed camera and a filter;

[0012] The plasma device is used to provide a high enthalpy plasma flow;

[0013] The heat protection material is installed in the test chamber of the plasma equipment and is aligned with the center of the nozzle that ejects plasma, and is used to simulate the thermal environment of an aircraft flying at a hypersonic speed;

[0014] The linear servo motor translation stage is matched and arranged on the outside of the plasma device;

[0015] The optical measuring device is matched and mounted on the linear servo motor displacement stage, and the linear servo motor displacement stage is controlled by the computer to synchronously adjust the position of the optical measuring device to measure the parameters of the required spatial position in the ablation boundary layer;

[0016] The filter is matched and installed in front of the lens of the high-speed camera, so as to collect high-frame-rate and high-resolution radiation images in the band selected by the filter;

[0017] The computer is located outside the plasma device and is connected to the linear servo motor translation stage and the high-speed camera respectively; the computer receives the radiation image collected by the high-speed camera, processes the collected radiation image to obtain the position change information of the ablation boundary layer of the heat-resistant material, and feeds back the information to the linear servo motor translation stage.

[0018] The method for dynamically identifying and tracking the spatial measurement position of the ablation boundary layer, wherein: for TDLAS measurement, the optical measurement device includes a TDLAS transmitter and a TDLAS receiver, and the linear servo motor translation stage is respectively matched and arranged on the outer side of the plasma device located on two opposite sides of the heat protection material; the TDLAS transmitter and the TDLAS receiver are respectively matched and installed on the linear servo motor translation stage located on two opposite sides of the heat protection material.

[0019] The method for dynamically identifying and tracking the spatial measurement position of the ablation boundary layer, wherein: for OES measurement, the optical measurement device only includes an OES receiving end, and the linear servo motor translation stage is matched and installed on the outer side of the plasma device located on one side of the heat protection material; the OES receiving end is matched and installed on the linear servo motor translation stage located on one side of the heat protection material.

[0020] The method for dynamically identifying and tracking the spatial measurement position of the ablation boundary layer, wherein: for LIF measurement, the optical measurement device only includes a LIF transmitter, and the linear servo motor translation stage is matched and installed on the outer side of the plasma device located on the side of the heat protection material; the LIF transmitter is matched and installed on the linear servo motor translation stage located on the side of the heat protection material.

[0021] The method for dynamically identifying and tracking the spatial measurement position of the ablation boundary layer, wherein: the step (2) is to use the spectrometer to collect the emission spectrum information of the ablation boundary layer of the heat protection material, and then draw the emission spectrum line based on the acquired emission spectrum information, and then query the publicly used spectrum database according to the emission spectrum line and the chemical element composition of the experimental environment to find the element corresponding to each peak in the spectrum line, that is, the main radiation component of the ablation boundary layer of the heat protection material used.

[0022] The method for dynamic identification and tracking of the spatial measurement position of the ablation boundary layer, wherein: the step (3) is based on the radiation components and their wavelengths that appear throughout the ablation process of the heat-resistant material used and have appropriate radiation intensity, and selects the corresponding filter and installs it in front of the lens of the high-speed camera to effectively filter out the radiation interference caused by the surrounding flow of the heat-resistant material, so that the surface contour of the heat-resistant material is clearly visible, and the area where the ablation boundary layer is located is confirmed. Finally, the radiation image of the heat-resistant material and the surrounding flow field is continuously collected by the high-speed camera equipped with the filter.

[0023] The method for dynamic identification and tracking of the spatial measurement position of the ablation boundary layer, wherein: in the step (3), each frame of the radiation image is read in real time by the computer, the position of the surface of the heat-resistant material in the radiation image is identified using an edge detection algorithm, and the result of the current frame is compared with the previous frame to obtain the displacement change of the surface position of the heat-resistant material, that is, the position change information of the ablation boundary layer of the heat-resistant material.

[0024] The method for dynamically identifying and tracking the spatial measurement position of the ablation boundary layer, wherein the specific process of using the edge detection algorithm to identify the position of the surface of the heat-resistant material in the radiation image is as follows: first, based on the characteristic that the flow field radiation is stronger than the heat-resistant material radiation in the radiation image, and there is an obvious intensity gradient between the two, the Sobel edge detection method is used to obtain the edges with obvious gradients in the image, and then the detected edges are used with a boundary tracking algorithm to obtain all boundaries, further excluding messy non-material edges, and finally identifying the surface position that conforms to the actual situation.

[0025] The method for dynamic identification and tracking of the spatial measurement position of the ablation boundary layer, wherein: in the step (3), the computer converts the acquired position change information of the ablation boundary layer of the heat-resistant material into a displacement signal and feeds it back to the linear servo motor displacement stage, and the linear servo motor displacement stage drives the optical measuring device to move the corresponding displacement amount to achieve synchronous adjustment of the position of the optical measuring device, and then the synchronously adjusted optical measuring device is used to achieve real-time dynamic measurement of the required spatial position parameters in the ablation boundary layer.

[0026] By adopting the above technical solution, the present invention has the following beneficial effects:

[0027] The method for dynamic identification and tracking of the spatial measurement position of the ablation boundary layer of the present invention is reasonably conceived and can accurately analyze the gas-solid coupling effect in the boundary layer, thus overcoming the problem that existing optical means are difficult to adapt to the dynamic changes of the ablation boundary layer when measuring the boundary layer parameters of heat-resistant materials.

[0028] The present invention is based on the different characteristics of the reactions of different heat-resistant materials in aerodynamic thermal assessment. According to the spectral information of the boundary layer, a suitable filter is selected and installed in front of a high-speed camera to capture radiation images. The area where the ablation boundary layer is located can be confirmed in the experiment, and the radiation interference caused by the circumference around the heat-resistant material can be effectively filtered out, so that the surface contour of the heat-resistant material is clearly visible, the time and complexity of image processing are reduced, and the calculation error is reduced.

[0029] The present invention can adapt to the movement and change of the material ablation boundary layer in the aerodynamic thermal assessment experiment of the heat-resistant material, especially in the case of ablation deformation of the heat-resistant material, and synchronously adjust the optical measurement equipment, so as to more accurately obtain the ablation boundary layer parameters, which is helpful to analyze the multi-process coupling mechanism in the boundary layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 It is a structural principle diagram of the ablation boundary layer optical dynamic measurement system arranged in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the surface emission spectrum of the C / SiC heat protection material collected in an embodiment of the present invention;

[0033] Figure 3The radiation image of the heat-resistant material in the high-enthalpy plasma flow directly collected by a high-speed camera in an embodiment of the present invention and the 388nmCN radiation image with a filter added;

[0034] Figure 4 Schematic diagram of edges with obvious intensity gradients in a radiation image obtained by using the Sobel edge detection method in an embodiment of the present invention;

[0035] Figure 5 A schematic diagram of the surface position of the heat-resistant material finally calculated in an embodiment of the present invention;

[0036] Figure 6 Schematic diagram of the surface displacement of C / SiC material calculated in an embodiment of the present invention. DETAILED DESCRIPTION

[0037] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. 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] The present invention is further explained below in conjunction with specific implementation modes.

[0039] like Figure 1 As shown, the present embodiment provides a method for dynamically identifying and tracking the spatial measurement position of an ablation boundary layer, which specifically includes the following steps:

[0040] S100, first deploying an ablation boundary layer optical dynamic measurement system for dynamic identification and tracking of ablation boundary layer spatial measurement position;

[0041] S200, collecting emission spectrum information of the ablation boundary layer of the heat protection material through the deployed ablation boundary layer optical dynamic measurement system, and determining the main radiation components and wavelengths in the ablation boundary layer of the heat protection material used by analyzing the obtained emission spectrum information.

[0042] S300, then collect the radiation image of the heat-resistant material and its surrounding flow field through the deployed ablation boundary layer optical dynamic measurement system, read and process the position change information of the ablation boundary layer of the heat-resistant material in each frame of the image in real time, and dynamically measure the parameters of the required spatial position in the ablation boundary layer in real time to realize the dynamic identification and tracking of the spatial measurement position of the ablation boundary layer.

[0043] In the embodiment of the present invention, by arranging Figure 1The optical dynamic measurement system of the ablation boundary layer shown in the figure is used to realize the dynamic identification and tracking of the spatial measurement position of the ablation boundary layer; wherein, the optical dynamic measurement system of the ablation boundary layer includes a plasma device, a linear servo motor displacement stage, an optical measurement device, a computer, a high-speed camera and a filter; wherein, Figure 1 In the figure, the plasma device (top view) shows the positional relationship between the optical measurement device and the plasma device, and the plasma device (bottom view) shows the positional relationship between the high-speed camera and the plasma device.

[0044] The plasma device is used to provide a high-enthalpy plasma flow; the plasma device consists of an ICP generator, a supersonic nozzle, a test chamber and a vacuum system; the left and right sides of the test chamber are matched with optical windows for optical measuring equipment to measure, and the top is provided with an optical window for high-speed camera to shoot.

[0045] The heat protection material is installed in the test chamber of the plasma equipment and is aligned with the center of the nozzle that ejects plasma, and is used to simulate the thermal environment of an aircraft flying at a hypersonic speed.

[0046] The optical measuring device is mounted on a linear servo motor displacement platform. The position of the optical measuring device can be adjusted by controlling the linear servo motor displacement platform through a computer, so as to measure the parameters of the required spatial position in the ablation boundary layer.

[0047] A filter is matched and installed in front of the lens of the high-speed camera to collect high-frame rate and high-resolution radiation images in the band selected by the filter.

[0048] The computer is located outside the plasma device and is connected to the linear servo motor translation stage and the high-speed camera respectively. It is used to receive the radiation image collected by the high-speed camera, process the radiation image, obtain the position change information of the ablation boundary layer of the heat-resistant material, and feed it back to the linear servo motor translation stage.

[0049] Furthermore, the above step S300 is based on the radiation components and wavelengths that appear throughout the ablation process of the heat-shielding material and have appropriate radiation intensity, and selects a corresponding filter and installs it in front of the lens of the high-speed camera to effectively filter out the radiation interference caused by the vortex around the heat-shielding material, so that the surface contour of the heat-shielding material is clearly visible, confirm the area where the ablation boundary layer is located, and finally continuously collect radiation images of the heat-shielding material and the flow field around it through a high-speed camera equipped with a filter. Among them, selecting a suitable filter for collecting radiation images can reduce the impact of strong radiation vortex on image processing.

[0050] In the above step S300, the acquired position change information of the ablation boundary layer of the heat-resistant material is converted into a displacement signal by a computer and fed back to the linear servo motor displacement stage. The linear servo motor displacement stage drives the optical measuring device to move the corresponding displacement amount to realize the synchronous adjustment of the position of the optical measuring device, and then the synchronously adjusted optical measuring device is used to realize the real-time dynamic measurement of the required spatial position parameters in the ablation boundary layer.

[0051] In this embodiment, a typical C / SiC thermal protection material is used for dynamic identification and tracking of the ablation boundary layer space measurement position, and TDLAS is used to measure parameters. Therefore, the optical measurement device includes a TDLAS transmitter and a TDLAS receiver, which are respectively installed on both sides of the C / SiC thermal protection material.

[0052] In this embodiment, the spectrometer measures the spectral information of the surface position of the C / SiC material, and the emission spectrum lines drawn are as follows: Figure 2 As shown. It can be seen that there is obvious CN radiation near 385nm-388nm, especially the CN radiation intensity at 388nm wavelength is moderate and runs through the entire material ablation process. Therefore, this embodiment selects a 388nm filter for CN radiation; as for O and N radiation appearing in the range of 700nm to 900nm, since they originate from the flow field itself and are almost distributed throughout the flow field, their role in distinguishing the bypass flow is limited, and this wavelength range is more susceptible to interference from blackbody radiation, so it is not considered.

[0053] Furthermore, it should be noted that, due to the different reactions of different heat shielding materials in high enthalpy flow, the characteristic components that can characterize their boundary layers are also different. For ease of explanation, this embodiment selects C / SiC heat shielding material as the measurement object. If other heat shielding materials are used, such as C / C, SiC or C / SiC-ZrB2, their main radiation components of the ablation boundary layer will be different, and accordingly, the required filters will also be different.

[0054] In this embodiment, a high-speed camera equipped with a 388nm filter continuously collects radiation images of the heat-resistant material and the flow field around it, and each frame of the image is read and processed by a computer in real time.

[0055] Furthermore, a frame of radiation image of the high enthalpy plasma of the heat shield material collected by a high-speed camera equipped with a 388nm filter is shown in FIG. Figure 3 As shown in the grayscale image on the right; compare it with Figure 3Comparing the radiation images collected without filters on the left side under the same working conditions, it can be clearly seen that the former can accurately indicate the position of the ablation boundary layer by capturing the radiation of the main component CN on the surface of the heat protection material, while effectively shielding the radiation interference generated by the surrounding circulation. This makes the outline of the surface of the heat protection material clearer, forming a sharp contrast with the radiation of the surrounding flow field, thereby simplifying the subsequent image processing process, shortening the processing time and reducing the complexity.

[0056] Furthermore, the collected image is processed using an edge detection algorithm. In this embodiment, Figure 3 Take a certain frame of CN radiation image as an example to illustrate image processing. First, based on the characteristics that the flow field radiation is stronger than the heat shield material radiation in the radiation image, and there is an obvious intensity gradient between the two, the Sobel edge detection method is used to obtain the edges with obvious gradients in the image. The detection results are shown in Figure 4 Ideally, the identified material edge should be Figure 4 The long vertical line on the left side corresponds to the material surface, but because there is also a certain intensity gradient at the edge of the CN radiation field, Figure 4 A messy vertical line appears on the right side of the detected model surface.

[0057] The above Sobel edge detection method uses the Sobel operator The image is convolved to obtain gradient images in the horizontal and vertical directions respectively, and then the gradients in the two directions are merged to obtain a gradient amplitude image; then a threshold is set, and the pixels with gradient amplitudes greater than the threshold are determined as edge points, generating a binary edge image, thereby obtaining the edge of the image.

[0058] Furthermore, the detected edges are subjected to a boundary tracking algorithm to obtain all boundaries, and based on the fact that the edges of the material surface are clear and obvious, the detected boundaries are also more continuous. This feature further eliminates the messy non-material edges (specifically, starting from a certain pixel point of the detected edge, searching the 8 pixels around it in a clockwise direction to find the first edge point, and then taking this point as the center, continue to search the 8 pixels around it in a clockwise direction, and repeat this process until returning to the starting point or there is no next point around, and finally obtaining all the boundaries in the edge obtained by Sobel edge detection, and the longest boundary is the material surface), and finally identifying the surface position that conforms to the actual situation; the results are as follows: Figure 5 As shown by the thick white solid line in the middle, it can be seen that the surface of the heat-resistant material model detected and identified by the edge detection algorithm is consistent with the actual image.

[0059] In this embodiment, each frame of radiation image is read and processed by a computer in real time. The surface of the heat-resistant material is identified by the above-mentioned edge detection algorithm, and the result of the current frame is compared with the previous frame to obtain the displacement change of the surface position of the heat-resistant material, that is, the position change information of the ablation boundary layer of the heat-resistant material.

[0060] Furthermore, each frame of calculated position change information of the ablation boundary layer of the heat-resistant material will be immediately fed back to the linear servo motor translation stage equipped with the TDLAS transmitter and receiver, which will drive the TDLAS transmitter and receiver to move, and synchronously adjust the optical measurement position according to the boundary layer position change information, thereby realizing dynamic identification and tracking of the spatial measurement position of the ablation boundary layer.

[0061] Furthermore, in this embodiment, the acquisition frame rate of the high-speed camera is set to 5fps, and the processing time of each frame image is about 0.1s. The reaction time of the linear servo motor is very small and can be ignored. Therefore, the total image processing time is less than 0.2s at the acquisition frame rate of 5fps, which meets the requirement of processing each frame image. The calculated surface displacement of the C / SiC material is as follows Figure 6 As shown, the material surface moves forward as positive; the specific calculation process is: detect the surface position of the heat-resistant material in the image by the above method, subtract the detection position result of the current frame from that of the previous frame, and the surface displacement of the heat-resistant material at the current moment can be obtained. This process is performed for each frame of the image to obtain the real-time surface displacement of the heat-resistant material; Figure 6 That is the material surface displacement calculated in this embodiment.

[0062] For OES measurement, the optical measurement equipment only includes an OES receiving end, and a linear servo motor translation stage is installed on the outer side of the plasma device located on one side of the heat protection material; the OES receiving end is installed on the linear servo motor translation stage located on one side of the heat protection material.

[0063] For LIF measurement, the optical measurement device only includes the LIF transmitter, and a linear servo motor translation stage is installed on the outer side of the plasma device located on the side of the heat protection material; the LIF transmitter is installed on the linear servo motor translation stage located on the side of the heat protection material.

[0064] The present invention has a reasonable concept and can accurately analyze the gas-solid coupling effect in the boundary layer, thus overcoming the problem that the existing optical means are difficult to adapt to the dynamic changes of the ablation boundary layer when measuring the boundary layer parameters of the heat protection material.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for dynamic identification and tracking of spatial measurement position of an ablation boundary layer, characterized in that: The following steps are involved: (1) First, deploy an optical dynamic measurement system for the ablation boundary layer for dynamic identification and tracking of the spatial measurement position of the ablation boundary layer; (2) collecting emission spectrum information of the ablation boundary layer of the heat protection material by using the ablation boundary layer optical dynamic measurement system arranged in step (1), and determining the radiation component and wavelength in the ablation boundary layer of the heat protection material used by analyzing the obtained emission spectrum information; (3) Then, the ablation boundary layer optical dynamic measurement system deployed in step (1) collects the radiation image of the heat-resistant material and the flow field around it, reads and processes each frame of the radiation image in real time to obtain the position change information of the ablation boundary layer of the heat-resistant material, and then dynamically measures the parameters of the required spatial position in the ablation boundary layer in real time, and finally realizes the dynamic identification and tracking of the spatial measurement position of the ablation boundary layer.

2. The method for dynamic identification and tracking of the ablation boundary layer spatial measurement position according to claim 1, characterized in that: The optical dynamic measurement system of the ablation boundary layer in step (1) comprises a plasma device, a linear servo motor translation stage, an optical measurement device, a computer, a high-speed camera and a filter; The plasma device is used to provide a high enthalpy plasma flow; The heat protection material is installed in the test chamber of the plasma equipment and is aligned with the center of the nozzle that ejects plasma, and is used to simulate the thermal environment of an aircraft flying at a hypersonic speed; The linear servo motor translation stage is matched and arranged on the outside of the plasma device; The optical measuring device is matched and mounted on the linear servo motor displacement stage, and the linear servo motor displacement stage is controlled by the computer to synchronously adjust the position of the optical measuring device to measure the parameters of the required spatial position in the ablation boundary layer; The filter is matched and installed in front of the lens of the high-speed camera, so as to collect high-frame-rate and high-resolution radiation images in the band selected by the filter; The computer is located outside the plasma device and is connected to the linear servo motor translation stage and the high-speed camera respectively; the computer receives the radiation image collected by the high-speed camera, processes the collected radiation image to obtain the position change information of the ablation boundary layer of the heat-resistant material, and feeds back the information to the linear servo motor translation stage.

3. The method for dynamic identification and tracking of the ablation boundary layer spatial measurement position according to claim 2, characterized in that: For TDLAS measurement, the optical measuring device includes a TDLAS transmitting end and a TDLAS receiving end, and the linear servo motor translation stage is respectively matched and arranged on the outer side of the plasma device located on two opposite sides of the heat protection material; the TDLAS transmitting end and the TDLAS receiving end are respectively matched and installed on the linear servo motor translation stage located on two opposite sides of the heat protection material.

4. The method for dynamic identification and tracking of the ablation boundary layer spatial measurement position according to claim 2, characterized in that: For OES measurement, the optical measurement device only includes an OES receiving end, and the linear servo motor translation stage is matched and installed on the outer side of the plasma device located on one side of the heat protection material; the OES receiving end is matched and installed on the linear servo motor translation stage located on one side of the heat protection material.

5. The method for dynamic identification and tracking of the ablation boundary layer spatial measurement position according to claim 2, characterized in that: For LIF measurement, the optical measurement device only includes a LIF transmitter, and the linear servo motor translation stage is matched and installed on the outer side of the plasma device located on the side of the heat protection material; the LIF transmitter is matched and installed on the linear servo motor translation stage located on the side of the heat protection material.

6. The method for dynamic identification and tracking of the ablation boundary layer spatial measurement position according to claim 2, characterized in that: The step (2) is to use the spectrometer to collect emission spectrum information of the ablation boundary layer of the heat protection material, and then draw emission spectrum lines based on the acquired emission spectrum information, and then query the publicly available spectrum database according to the emission spectrum lines and the chemical element composition of the experimental environment to find the elements corresponding to each peak in the spectrum line, that is, the main radiation components of the ablation boundary layer of the heat protection material used.

7. The method for dynamic identification and tracking of the ablation boundary layer spatial measurement position according to claim 2, characterized in that: The step (3) is to select the corresponding filter and install it in front of the lens of the high-speed camera based on the radiation components and their wavelengths that appear throughout the ablation process of the heat-resistant material used and have appropriate radiation intensity, so as to effectively filter out the radiation interference caused by the surrounding flow of the heat-resistant material, make the surface contour of the heat-resistant material clearly visible, confirm the area where the ablation boundary layer is located, and finally continuously collect radiation images of the heat-resistant material and the surrounding flow field through the high-speed camera installed with the filter.

8. The method for dynamic identification and tracking of the ablation boundary layer spatial measurement position according to claim 2, characterized in that: In the step (3), each frame of the radiation image is read in real time by the computer, the position of the surface of the heat-resistant material in the radiation image is identified using an edge detection algorithm, and the result of the current frame is compared with the previous frame to obtain the displacement change of the surface position of the heat-resistant material, that is, the position change information of the ablation boundary layer of the heat-resistant material.

9. The method for dynamic identification and tracking of the ablation boundary layer spatial measurement position according to claim 8, characterized in that: The specific process of using the edge detection algorithm to identify the position of the surface of the heat-resistant material in the radiation image is as follows: first, based on the characteristic that the flow field radiation is stronger than the heat-resistant material radiation in the radiation image and there is an obvious intensity gradient between the two, the Sobel edge detection method is used to obtain the edges with obvious gradients in the image, and then the detected edges are subjected to the boundary tracking algorithm to obtain all boundaries, further eliminate the messy non-material edges, and finally identify the surface position that conforms to the actual situation.

10. The method for dynamic identification and tracking of the ablation boundary layer spatial measurement position according to claim 2, characterized in that: In the step (3), the computer converts the acquired position change information of the ablation boundary layer of the heat-resistant material into a displacement signal and feeds it back to the linear servo motor displacement stage. The linear servo motor displacement stage drives the optical measuring device to move the corresponding displacement amount to achieve synchronous adjustment of the position of the optical measuring device, and then the synchronously adjusted optical measuring device is used to achieve real-time dynamic measurement of the required spatial position parameters in the ablation boundary layer.

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