Optical measurement method and device for vibration combustion response function of solid propellant

Abstract

The present application relates to a kind of solid propellant vibration combustion response function optical measurement method and device, the combustion response of solid propellant under vibration condition is characterized by solid propellant vibration combustion response function, first by solid propellant vibration combustion response function experimental system obtains the dynamic combustion image of propellant vibration condition, then by the image processing method established obtains the combustion response function of propellant under vibration condition.The present application can realize quantitative analysis vibration to the influence of solid propellant combustion.

Description

Technical Field

[0001] This invention relates to the field of solid propellant combustion technology, and in particular to an optical measurement method and apparatus for the vibration combustion response function of solid propellants. Background Technology

[0002] During missile flight, the interaction between the missile body and the air causes vibrations. These vibrations occur to varying degrees during acceleration, high-G operations, and attitude control phases, and are transmitted to the solid rocket motor. Simultaneously, the solid rocket motor itself may also vibrate during operation, such as when debris passes through its throat. Therefore, solid rocket motors are always accompanied by vibration during operation.

[0003] Vibration causes solid propellant to reciprocate periodically. During this process, the thermal feedback of the propellant flame and the combustion process of propellant particles are altered to varying degrees due to vibration, leading to combustion instability. In some cases, vibration can severely affect the operation of solid rocket motors, causing changes in the internal trajectory and even potentially causing the solid rocket motor to explode. Therefore, it is necessary to study the mechanism of vibration's influence on solid propellant combustion. However, existing technologies have very few studies on the mechanism of vibration's influence on solid propellant combustion, and there is a lack of analytical methods for analyzing the impact of vibration on solid propellant combustion. Summary of the Invention

[0004] Therefore, it is necessary to provide an optical measurement method and apparatus for the vibration combustion response function of solid propellants to address the above-mentioned technical problems, so as to obtain the vibration combustion response function of solid propellants and study the combustion response characteristics of solid propellants under vibration conditions.

[0005] In a first aspect, the present invention provides an optical measurement method for the vibration combustion response function of a solid propellant, wherein the calculation formula for the vibration combustion response function is as follows:

[0006]

[0007] In the formula, R A (f) represents the value of the solid propellant vibration combustion response function at vibration frequency f, and V′ represents the fluctuation of the propellant burning rate. V represents the average burning rate of the propellant under vibration conditions. Let X' be the average burning rate of the propellant when there is no vibration, and X′ be the displacement fluctuation due to vibration. This indicates the equilibrium position of the propellant when there is no vibration. The value is defined as 1 unit displacement.

[0008] In one embodiment, the optical measurement method for the vibrational combustion response function of solid propellants includes:

[0009] Acquire dynamic combustion images of solid propellant and motion images of the vibration detector under vibration conditions;

[0010] Image processing was performed on each frame of the dynamic combustion image of solid propellant to obtain an image of the propellant combustion surface height changing over time.

[0011] Image processing is performed on each frame of the vibration detector motion image to obtain an image of the detector motion surface height changing over time;

[0012] The displacement fluctuation of the vibration is obtained from the image of the change of the height of the detector's moving surface over time;

[0013] The average burning rate of the propellant under vibration conditions was determined by the graph of the propellant burning surface height changing over time.

[0014] Obtain the average burning rate of the propellant under vibration-free conditions;

[0015] The vibration combustion response function is calculated based on the formula for the vibration combustion response function, the displacement fluctuation of the vibration, the average burning rate of the propellant under vibration conditions, and the average burning rate of the propellant under no vibration conditions.

[0016] In one embodiment, image processing is performed on each frame of the dynamic combustion image of solid propellant to obtain an image showing the change of propellant combustion surface height over time, including:

[0017] The dynamic combustion images of solid propellant at each moment are captured laterally. The captured dynamic combustion images are binarized and subjected to corrosion and dilation processing to obtain continuous propellant combustion surface boundary images at each moment.

[0018] The average height of each pixel in the propellant burning surface boundary image at each time step is calculated as the propellant burning surface height at each time step.

[0019] Plot a graph showing the change of propellant burn-up height over time based on the propellant burn-up height at each moment.

[0020] In one embodiment, image processing is performed on each frame of the vibration detector motion image to obtain an image showing the change in the height of the detector motion surface over time, including:

[0021] The motion image of the vibration detector at each moment is captured laterally, and the captured vibration detector motion is binarized and subjected to erosion and dilation processing to obtain a continuous boundary image of the detector motion surface at each moment.

[0022] The average height of each pixel in the boundary image of the detector motion surface at each time step is calculated as the height of the detector motion surface at each time step.

[0023] The image showing the change of the detector's moving surface height over time is plotted based on the detector's moving surface height at each moment.

[0024] In one embodiment, obtaining the displacement fluctuation of the vibration based on an image of the detector's moving surface height changing over time includes:

[0025] FFT bandpass filtering was applied to the image of the detector's moving surface height changing over time.

[0026] The image of the detector motion surface height changing over time after FFT bandpass filtering is smoothed. The smoothing process involves calculating the height of the vibration equilibrium position using the adjacent averaging method.

[0027] The vibration data curve with 0 as the equilibrium position is obtained by subtracting the smoothed image data from the image data of the detector motion surface height change over time after FFT bandpass filtering.

[0028] The upper and lower envelopes are obtained based on the vibration curve, and the average height of each envelope is calculated.

[0029] The displacement fluctuation of the vibration is obtained by subtracting the average height of the lower envelope from the average height of the upper envelope.

[0030] In one embodiment, determining the average burning rate of the propellant under vibration conditions based on a graph showing the propellant burning surface height changing over time includes:

[0031] By subtracting the displacement of the vibration detector from the propellant burning surface displacement at the same moment, an image showing the change of the propellant's own burning surface height retreat over time can be obtained.

[0032] The image of the propellant's own combustion surface height retreat over time was smoothed to obtain a smooth curve;

[0033] The smooth curve is fitted, and the absolute value of the slope of the straight line obtained by fitting the smooth curve is determined to be the average burning rate of the propellant under vibration conditions.

[0034] Secondly, the present invention also provides an optical measurement device for the vibration combustion response function of solid propellants. The device includes an excitation system, a vibration combustion support, an optical measurement system, and a processing module;

[0035] The excitation system is equipped with a function generator, a power controller, and an exciter, with the power controller electrically connected between the function generator and the exciter.

[0036] The vibration combustion support consists of a propellant clamping part and a vibration detector. The propellant clamping part is fixedly connected to the vibration table of the exciter, and the vibration detector is a rigid thin sheet. The vibration detector and the propellant strip clamped by the propellant clamping part are located on the same plane.

[0037] The optical measurement system includes a laser, a high-speed camera, a filter, a telephoto macro lens, and a data acquisition module. The laser beam passes through the propellant strip and the vibration detector before entering the telephoto macro lens. The filter is located on one side of the telephoto macro lens, which is positioned next to the vibration detector. The telephoto macro lens is connected to the high-speed camera, and the data acquisition system is electrically connected to the high-speed camera.

[0038] The processing module is electrically connected to the optical measurement system and is used to process the image data obtained by the optical measurement system and calculate the value of the solid propellant vibration combustion response function.

[0039] In one embodiment, the laser is a 532nm laser and the filter is a 532nm filter.

[0040] The beneficial effects of this invention are:

[0041] (1) This invention characterizes the combustion response of solid propellants under vibration by using the solid propellant vibration combustion response function, which can realize quantitative analysis of the influence of vibration on solid propellant combustion.

[0042] (2) The present invention processes the propellant image under vibration conditions, which can accurately obtain the change in the burning rate of the propellant, thereby obtaining the vibration combustion response of the propellant.

[0043] (3) The present invention uses the backlight shadow method to photograph the propellant combustion process, which can filter out the interference of the propellant's self-luminescence. At the same time, the propellant burning surface obtained by using laser as a backlight source has a clearer outline, which can improve the resolution of the optical measurement system for the burning surface fluctuation. Attached Figure Description

[0044] Figure 1 This is one of the flowcharts illustrating the optical measurement method for the vibration combustion response function of solid propellants provided in this embodiment of the invention;

[0045] Figure 2 These are dynamic combustion images of solid propellant and motion images of the vibration detector under vibration conditions provided in the embodiments of the present invention.

[0046] Figure 3 This is one of the flowcharts illustrating the optical measurement method for the vibration combustion response function of solid propellants provided in this embodiment of the invention;

[0047] Figure 4 This is a schematic diagram of a dynamic combustion image capture of solid propellant provided in an embodiment of the present invention;

[0048] Figure 5 This is a schematic diagram of binarization processing and corrosion expansion processing in an embodiment of the present invention;

[0049] Figure 6 This is a schematic diagram illustrating the calculation of propellant burning surface height at each moment, provided in an embodiment of the present invention.

[0050] Figure 7 This is one of the images showing the change of propellant burning surface height over time provided in the embodiments of the present invention;

[0051] Figure 8 This is one of the flowcharts illustrating the optical measurement method for the vibration combustion response function of solid propellants provided in this embodiment of the invention.

[0052] Figure 9 This is a schematic diagram of motion image capture of a vibration detector provided in an embodiment of the present invention;

[0053] Figure 10 This is one of the images showing the change in the height of the detector's moving surface over time, provided in an embodiment of the present invention.

[0054] Figure 11 This is one of the flowcharts illustrating the optical measurement method for the vibration combustion response function of solid propellants provided in this embodiment of the invention.

[0055] Figure 12 This is a schematic diagram of FFT bandpass filtering provided in an embodiment of the present invention;

[0056] Figure 13 This is the vibration data curve provided in the embodiment of the present invention;

[0057] Figure 14 This is a schematic diagram of the upper and lower envelopes provided in an embodiment of the present invention;

[0058] Figure 15 This is one of the flowcharts illustrating the optical measurement method for the vibration combustion response function of solid propellants provided in this embodiment of the invention.

[0059] Figure 16 This is a schematic diagram of the image acquisition of the change in the burning surface height retreat of the propellant itself over time, provided in an embodiment of the present invention;

[0060] Figure 17 This is a schematic diagram of a smooth curve provided in an embodiment of the present invention;

[0061] Figure 18 This is one of the structural schematic diagrams of the optical measurement device for the vibration combustion response function of solid propellant provided in the embodiments of the present invention.

[0062] Explanation of reference numerals in the attached figures: 1. Function generator; 2. Power controller; 3. Exciter; 4. Propellant clamping part; 5. Vibration detector; 6. Laser; 7. High-speed camera; 8. Filter; 9. Telephoto macro lens; 10. Acquisition module; 11. Propellant strip; 12. Processing module. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0064] In one embodiment, the formula for calculating the vibration combustion response function in the optical measurement method of the solid propellant vibration combustion response function of the present invention is:

[0065]

[0066] In the formula, R A (f) represents the value of the solid propellant vibration combustion response function at vibration frequency f, and V′ represents the fluctuation of the propellant burning rate. V represents the average burning rate of the propellant under vibration conditions. Let X' be the average burning rate of the propellant when there is no vibration, and X′ be the displacement fluctuation due to vibration. This indicates the equilibrium position of the propellant when there is no vibration. The value is defined as 1 unit displacement.

[0067] Specifically, the displacement fluctuation of vibration is the peak-to-peak value of the displacement relative to the equilibrium position. Because... and The value is defined as 1 unit displacement, so the formula for calculating the vibration combustion response function can be written as:

[0068]

[0069] By studying the vibrational combustion response function R of different types of solid propellants at different frequencies f and different amplitudes X′, A The value of (f) can be used to obtain the vibration combustion response characteristics of different types of solid propellants.

[0070] In one embodiment, such as Figure 1 As shown, Figure 1 This is one of the flowcharts illustrating the optical measurement method for the vibrational combustion response function of solid propellants provided in this embodiment of the invention. In this embodiment, the optical measurement method for the vibrational combustion response function of solid propellants includes the following steps:

[0071] S101. Acquire dynamic combustion images of the solid propellant and motion images of the vibration detector under vibration conditions. The dynamic combustion images of the solid propellant and motion images of the vibration detector under vibration conditions are as follows: Figure 2 As shown.

[0072] S102. Image processing is performed on each frame of the dynamic combustion image of solid propellant to obtain an image of the propellant burning surface height changing over time.

[0073] S103. Perform image processing on each frame of the vibration detector motion image to obtain an image of the detector motion surface height changing over time.

[0074] S104. Obtain the displacement fluctuation amount of the vibration based on the image of the change of the height of the detector's moving surface over time.

[0075] S105. Determine the average burning rate of the propellant under vibration conditions based on the graph of the propellant burning surface height changing over time.

[0076] S106. Obtain the average burning rate of the propellant under vibration-free conditions.

[0077] S107. The vibration combustion response function is calculated based on the formula, the displacement fluctuation of the vibration, the average burning rate of the propellant under vibration conditions, and the average burning rate of the propellant under no vibration conditions.

[0078] Specifically, the displacement fluctuation of the vibration, the average burning rate of the propellant under vibration conditions, and the average burning rate of the propellant under no vibration conditions are substituted into the equation. The vibration combustion response function is obtained from this.

[0079] The method of the present invention can accurately obtain the burning rate change of the propellant, thereby obtaining the vibration combustion response function of the propellant.

[0080] In one embodiment, such as Figure 3 As shown, Figure 3 This is one of the flowcharts illustrating the optical measurement method for the vibration combustion response function of solid propellant provided in this embodiment of the invention. This embodiment involves image processing of each frame of a dynamic combustion image of solid propellant to obtain an image showing the change in propellant combustion surface height over time. Based on the above embodiment, step S102 includes:

[0081] S301. Horizontally capture dynamic combustion images of solid propellant at each moment. Perform binarization and corrosion expansion processing on the captured dynamic combustion images to obtain continuous propellant combustion surface boundary images at each moment.

[0082] Specifically, such as Figure 4 As shown, Figure 4This is a schematic diagram of a dynamic combustion image capture of solid propellant provided in an embodiment of the present invention. The region in the middle of the propellant strip, with a width equal to half the total width of the propellant strip, is selected for analysis and capture because combustion in the middle region is more stable than at the ends. Figure 5 As shown, Figure 5 This is a schematic diagram of binarization and corrosion expansion processing in an embodiment of the present invention. During binarization, an appropriate threshold is selected to obtain a complete propellant burning surface while minimizing image noise.

[0083] S302. Calculate the average height of each pixel in the propellant burning surface boundary image at each time step as the propellant burning surface height at each time step.

[0084] Specifically, such as Figure 6 As shown, Figure 6 This is a schematic diagram illustrating the calculation of propellant burning surface height at each moment, provided in an embodiment of the present invention. It is assumed that the selected portion of the burning surface satisfies the parallel regression theory, meaning the propellant burning surface regresses downwards in the form of a plane. The average distance from each pixel on the propellant burning surface boundary curve obtained in S302 to the bottom of the image is calculated. This average value is used as the height of the horizontal burning surface in the parallel regression calculation method; that is, the average height of each pixel on the burning surface is used to represent the height of the propellant burning surface at this moment.

[0085] S303. Plot a graph showing the change of propellant burnup height over time based on the propellant burnup height at each moment. For example... Figure 7 As shown, Figure 7 This is one of the images showing the change of propellant burning surface height over time provided in an embodiment of the present invention.

[0086] In one embodiment, such as Figure 8 As shown, Figure 8 This is one of the flowcharts illustrating the optical measurement method for the vibration combustion response function of solid propellants provided in this embodiment of the invention. This embodiment involves processing each frame of the motion image of the vibration detector to obtain an image showing the change in the height of the detector's motion surface over time. Based on the above embodiment, step S103 includes:

[0087] S801. Horizontally capture the vibration detector motion image at each moment, and perform binarization and erosion dilation processing on the captured vibration detector motion to obtain a continuous detector motion surface boundary image at each moment.

[0088] S802. Calculate the average height of each pixel in the boundary image of the detector motion surface at each time step as the height of the detector motion surface at each time step.

[0089] S803. Draw an image of the detector moving surface height changing over time based on the detector moving surface height at each moment.

[0090] Specifically, such as Figure 9 As shown, Figure 9 This is a schematic diagram of motion image capture of the vibration detector provided in an embodiment of the present invention. Figure 10 As shown, Figure 10 This is one of the images showing the change in the height of the detector's moving surface over time, provided in an embodiment of the present invention.

[0091] In an optional embodiment, such as Figure 11 As shown, Figure 11 This is one of the flowcharts illustrating the optical measurement method for the vibration combustion response function of solid propellants provided in this embodiment of the invention. This embodiment relates to how to obtain the displacement fluctuation of vibration based on an image showing the change in the height of the detector's moving surface over time. Based on the above embodiment, step S104 includes:

[0092] S1101. Perform FFT bandpass filtering on the image of the detector's moving surface height changing over time.

[0093] Specifically, such as Figure 12 As shown, Figure 12 This is a schematic diagram of FFT bandpass filtering provided in an embodiment of the present invention. In this embodiment, the bandpass range of the FFT bandpass filtering is ±1 of the exciter vibration frequency, thereby filtering out noise in the curve.

[0094] S1102. The image of the detector motion surface height changing over time after FFT bandpass filtering is smoothed. The smoothing process involves calculating the height of the vibration equilibrium position using the adjacent averaging method.

[0095] Specifically, in the adjacent averaging method, the number of window points = camera sampling rate / vibration frequency.

[0096] S1103. The vibration data curve with 0 as the equilibrium position is obtained by subtracting the smoothed image data from the image data of the detector motion surface height changing over time after FFT bandpass filtering.

[0097] Specifically, the process of acquiring vibration data curves is as follows: Figure 13 As shown.

[0098] S1104. Obtain the upper and lower envelopes based on the vibration curve, and calculate the average height of each of the upper and lower envelopes.

[0099] like Figure 14 As shown, Figure 14 This is a schematic diagram of the upper and lower envelopes provided in an embodiment of the present invention.

[0100] S1105. Subtract the average height of the lower envelope from the average height of the upper envelope to obtain the displacement fluctuation of the vibration.

[0101] In one preferred embodiment, such as Figure 15 As shown, Figure 15 This is one of the flowcharts illustrating the optical measurement method for the vibration combustion response function of solid propellant provided in this embodiment of the invention. This embodiment relates to an optional method for determining the average burning rate of propellant under vibration conditions based on an image of the propellant burning surface height changing over time. Based on the above embodiment, step S105 includes:

[0102] S1501. Subtract the displacement of the vibration detector from the propellant burning surface displacement at the same moment to obtain a graph showing the change in the propellant's own burning surface height retraction over time. For example... Figure 16 As shown, Figure 16 This is a schematic diagram of the image acquisition of the change in the burning surface height retreat of the propellant itself over time, provided in an embodiment of the present invention.

[0103] The change in propellant burning surface height includes the amount of downward parallel retreat of the propellant during combustion and the amount of vertical movement of the propellant burning surface around the equilibrium position due to vibration. Since the vibration displacement of the propellant vertical movement is the same as the displacement of the vibration detector, the situation of the propellant's downward parallel retreat due to combustion can be obtained by subtracting the displacement of the vibration detector from the displacement of the propellant burning surface at the same moment. That is, the graph of the change in the amount of propellant burning surface height retreat over time.

[0104] S1502. The image of the change in the burning surface height of the propellant itself over time is smoothed to obtain a smooth curve.

[0105] Specifically, smoothing can filter out noise in an image, resulting in a smooth curve. For example... Figure 17 As shown, Figure 17 This is a schematic diagram of a smooth curve provided in an embodiment of the present invention.

[0106] S1503. Fit the smooth curve and determine the absolute value of the slope of the straight line obtained by fitting the smooth curve as the average burning rate of the propellant under vibration conditions.

[0107] In an optional embodiment, the propellant burning rate is calculated under vibration-free conditions: Since there is no vertical movement of the propellant burning surface around its equilibrium position due to vibration, the graph of the propellant burning surface height over time obtained under vibration-free conditions represents the change in the height of the propellant due to the downward parallel retreat of the burning surface over time. Therefore, the above method is used: first, the curve is smoothed, and then a linear fit is performed on the smoothed curve. The absolute value of the slope of the fitted straight line is the average burning rate of the propellant under vibration-free conditions.

[0108] Based on the same inventive concept, this invention also provides an optical measurement device for the vibration combustion response function of solid propellants, used to acquire images corresponding to the parameters required for calculating the vibration combustion response function, and to process and calculate the value of the vibration combustion response function of solid propellants. Figure 18 As shown, Figure 18 This is one of the structural schematic diagrams of an optical measurement device for the vibration combustion response function of solid propellant provided in this embodiment of the invention. The optical measurement device for the vibration combustion response function of solid propellant in this embodiment includes an excitation system, a vibration combustion support, an optical measurement system, and a processing module 12.

[0109] The vibration excitation system includes a function generator 1, a power controller 2, and a vibrator 3. The power controller 2 is electrically connected between the function generator 1 and the vibrator 3. The vibration excitation system uses a permanent magnet electric vibrator 3, which features small size, large excitation force, and a wide excitation frequency range. The waveform and frequency of the vibration are adjusted by the function generator 1, the amplitude of the vibration is adjusted by the power controller 2, and finally, the corresponding vibration is generated on the vibration table surface of the vibrator 3.

[0110] The permanent magnet electric vibrator 3 has a vibration frequency range of 0Hz-2000Hz. The selected high-speed camera 7 has a sampling rate of up to 20000Hz at a high resolution. The use of a telephoto macro lens 9 can further improve the resolution of the combustion surface. This system can study the propellant vibration combustion in the frequency range of 0-2000Hz.

[0111] The vibratory combustion support consists of a propellant clamping part 4 and a vibration detector 5. The propellant clamping part 4 is fixedly connected to the vibration table surface of the exciter 3. The vibration detector 5 is a rigid thin sheet, and the vibration detector 5 and the propellant strip 11 clamped by the propellant clamping part 4 are located on the same plane. Specifically, the propellant clamping device consists of two adjustable baffles, and the propellant strip 11 is fixed to the device by adjusting the distance between the two baffles. The vibration detector 5 records the movement process of its top during vibration, thereby analyzing the vibration information at each moment. The bottom of the vibratory combustion support is connected to the vibration table surface of the exciter 3 by bolts. When the exciter 3 vibrates, the vibratory combustion support drives the propellant strip 11 and the vibration detector 5 to vibrate synchronously.

[0112] The optical measurement system includes a laser 6, a high-speed camera 7, a filter 8, a telephoto macro lens 9, and an acquisition module 10. The laser light from the laser 6 passes through the propellant strip 11 and the vibration detector 5 before entering the telephoto macro lens 9. The filter 8 is located on one side of the telephoto macro lens 9, which is connected to the high-speed camera 7. The acquisition system is electrically connected to the high-speed camera 7. The processing module 12 is electrically connected to the optical measurement system and is used to process the image data obtained by the optical measurement system and calculate the value of the solid propellant vibration combustion response function.

[0113] Specifically, laser 6 is a 532nm laser, and filter 8 is a 532nm filter. The dynamic combustion process of the propellant during vibration is measured using the backlight shading method. The telephoto macro lens 9, filter 8, and high-speed camera 7 are connected sequentially. The 532nm laser generator serves as the background light source, allowing the laser to pass through the propellant strip 11 and the vibration detector 5 before entering the high-speed camera 7. The high-speed camera 7 can simultaneously acquire the dynamic combustion process of the propellant and the movement process of the vibration detector 5.

[0114] The 532nm filter 8 can filter out the self-illuminating flame of solid propellant and only receive the information carried by the background light source, so as to clearly see the changes in the burning surface. Compared with other light sources, the propellant burning surface outline obtained by laser as a backlight source is clearer, which can improve the system's resolution of burning surface fluctuations. Using a telephoto macro lens 9, the propellant burning surface can be magnified to the required magnification, so as to observe the changes in the propellant burning surface in more detail.

[0115] In a specific embodiment, the optical measurement apparatus and method for the vibration combustion response function of solid propellants of the present invention will be described from the aspects of device assembly and method implementation. The process of obtaining the value of the vibration combustion response function includes the following steps:

[0116] Step 1: Connect the function generator, controller, exciter, and propellant vibration combustion support; set the output waveform of the function generator to a sine wave and set the corresponding frequency; adjust the controller to a suitable power.

[0117] Step 2: Fix the cuboid bicomponent propellant strip to the vibration combustion bracket. Adjust the distance between the baffles using the two nuts on the bracket to clamp the bottom of the propellant. At the same time, adjust the vibration detector on the same plane as the propellant to a suitable height.

[0118] Step 3: Using a laser generator as a background light source, adjust the height of the 532nm laser so that the laser spot passes vertically through the propellant and vibration detector. Connect a telephoto macro lens in front of the high-speed camera, and then add a 532nm filter in front of it. Connect the high-speed camera to the acquisition computer, and adjust the camera's sampling rate and exposure time through the PCC camera control software. At the same time, adjust the telephoto macro lens to the required magnification. Then, adjust the height of the high-speed camera using the lifting platform so that the laser spot enters the camera lens evenly. Finally, adjust the camera's focal length so that the burning surface of the propellant can be clearly seen.

[0119] Step 4: Place the optical calibration plate on the same plane as the propellant and calibrate the pixel size at the current magnification.

[0120] Step 5: Start the vibrator under the set conditions. While igniting the propellant with a flame gun, the high-speed camera begins to record the propellant combustion process, and also records the movement of the vibration detector.

[0121] Step Six: Process the acquired images as follows: First, horizontally crop the images, selecting the middle half where combustion recession is relatively stable to study the combustion rate. Next, binarize the image and then perform erosion and dilation processing to obtain the boundary curve of the propellant combustion surface. Assuming this selected combustion surface satisfies the parallel recession theory, calculate the average height of each pixel on this boundary curve from the bottom of the image, and consider this average height as the current combustion surface height of the propellant. Then, batch process the images to obtain the combustion surface height in each image, thus obtaining the relationship between the propellant combustion surface height and time. Finally, plot the combustion surface height-time graph.

[0122] Step 7: Change the horizontal cropping range of the image to the vibration detector area, and then perform the same image processing steps on the vibration detector as on the propellant. This will give you the height of the vibration detector in each image, which will show the relationship between the height of the vibration detector and time. Then, draw a vibration height-time graph.

[0123] Step 8: Place the same type of propellant of the same size on the vibrating combustion support. Ignite the propellant with a spray gun when the exciter is off and there is no vibration. At the same time, use a high-speed camera to capture the propellant combustion process. Then perform the above image processing steps to obtain the relationship between the propellant burning surface and time when there is no vibration. Then draw the burning surface height-time image.

[0124] Step Nine: Next, the vibration displacement is obtained by processing the data on the change of the vibration detector height over time. First, the data is subjected to FFT bandpass filtering, with the bandpass range being ±1 of the exciter's vibration frequency, thus filtering out noise in the curve. Then, the data is smoothed using the adjacent averaging method, with the window number set to the camera sampling rate divided by the vibration frequency, to obtain the height of the vibration equilibrium position. Subtracting the smoothed data from the FFT bandpass filtered data yields the vibration information with 0 as the equilibrium position.

[0125] Step 10: Calculate the upper and lower envelopes of the vibration data curve, and find the average height of the upper and lower envelopes respectively. The value of the average height of the upper envelope minus the average height of the lower envelope is regarded as the peak-to-peak value of the vibration displacement, which is the fluctuation amount X′ of the vibration displacement in the vibration combustion response function.

[0126] Step 11: Process the data on the change of propellant burning surface over time under vibration conditions. The change of propellant burning surface includes the amount of downward parallel retreat of propellant combustion. At the same time, since the vibrating propellant burning surface is also moving up and down around the equilibrium position, and the amount of this up and down movement is the same as the amount of up and down movement of the vibration detector at each moment, the situation of the propellant moving downward parallel due to combustion can be obtained by subtracting the displacement of the vibration displacement bar from the displacement of the propellant burning surface at the same moment.

[0127] Step 12: Perform lowess smoothing on the curve obtained in the previous step to filter out noise points in the image that deviate from the baseline, resulting in a smooth curve. Perform linear fitting on this smooth curve, and the absolute value of the slope obtained from the fitting is the average burning rate V of the propellant under vibration conditions.

[0128] Step Thirteen: The processing of propellant burning surface height versus time data under vibration-free conditions is the same as in Step Twelve. First, the curve of propellant burning surface height versus time obtained under vibration-free conditions is smoothed using Lowess, and then linear fitting is performed. The absolute value of the slope of the fitted curve is the average burning rate of the propellant under vibration-free conditions.

[0129] Step Fourteen: Subtract the average burning rate of the propellant under no-vibration conditions from the average burning rate V of the propellant under vibration conditions. The fluctuation amount V′ of the combustion rate disturbance can be obtained.

[0130] Step 15: Analyze the vibration combustion response function The expression can be used to calculate the value of the vibration combustion response function of this propellant at the experimental vibration frequency f and amplitude X′.

[0131] This embodiment uses the solid propellant vibration combustion response function to characterize the combustion response of solid propellant under vibration conditions, which can realize quantitative analysis of the influence of vibration on solid propellant combustion.

[0132] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims

1. A method of optical measurement of the vibration combustion response function of a solid propellant, characterized in that, The formula for calculating the vibration combustion response function is as follows: ， In the formula, Indicates the vibration frequency as The value of the solid propellant vibration combustion response function at that time. This represents the fluctuation in propellant burning rate. = V - , V This represents the average burning rate of the propellant under vibration conditions. The average burning rate of the propellant when there is no vibration. This represents the displacement fluctuation of the vibration. This indicates the equilibrium position of the propellant when there is no vibration. The value is defined as 1 unit displacement; The method includes: Acquire dynamic combustion images of solid propellant and motion images of the vibration detector under vibration conditions; Each frame of the dynamic combustion image of the solid propellant is processed to obtain an image showing the change of the propellant combustion surface height over time; Image processing is performed on each frame of the vibration detector motion image to obtain an image of the detector motion surface height changing over time; The displacement fluctuation of the vibration is obtained from the image of the change of the height of the detector's moving surface over time; The average burning rate of the propellant under vibration conditions was determined based on the image showing the change of the propellant burning surface height over time. Obtain the average burning rate of the propellant under vibration-free conditions; The vibration combustion response function is calculated based on the formula for the vibration combustion response function, the displacement fluctuation of the vibration, the average burning rate of the propellant under vibration conditions, and the average burning rate of the propellant under no vibration conditions.

2. The optical measurement method of the solid propellant vibration combustion response function according to claim 1, characterized in that, Image processing is performed on each frame of the dynamic combustion image of the solid propellant to obtain an image showing the change of the propellant combustion surface height over time, including: The dynamic combustion images of solid propellant at each moment are captured laterally. The captured dynamic combustion images are binarized and subjected to corrosion and dilation processing to obtain continuous propellant combustion surface boundary images at each moment. The average height of each pixel in the propellant burning surface boundary image at each time step is calculated as the propellant burning surface height at each time step. Plot a graph showing the change of propellant burn-up height over time based on the propellant burn-up height at each moment.

3. The optical measurement method for the vibration combustion response function of solid propellants according to claim 1, characterized in that, Image processing is performed on each frame of the motion image of the vibration detector to obtain an image showing the change in the height of the detector's motion surface over time, including: The motion image of the vibration detector at each moment is captured laterally, and the captured vibration detector motion is binarized and subjected to erosion and dilation processing to obtain a continuous boundary image of the detector motion surface at each moment. The average height of each pixel in the boundary image of the detector motion surface at each time step is calculated as the height of the detector motion surface at each time step. The image showing the change of the detector's moving surface height over time is plotted based on the detector's moving surface height at each moment.

4. The optical measurement method for the vibrational combustion response function of solid propellants according to any one of claims 2 or 3, characterized in that, The displacement fluctuation of the vibration obtained from the image of the change in the height of the detector's moving surface over time includes: The image of the detector's moving surface height changing over time is processed by FFT bandpass filtering; The image of the detector motion surface height changing over time after FFT bandpass filtering is smoothed. The smoothing process involves calculating the height of the vibration equilibrium position using the adjacent averaging method. The vibration data curve with 0 as the equilibrium position is obtained by subtracting the smoothed image data from the image data of the detector motion surface height change over time after FFT bandpass filtering. The upper and lower envelopes are obtained based on the vibration data curves, and the average height of each envelope is calculated. The displacement fluctuation of the vibration is obtained by subtracting the average height of the lower envelope from the average height of the upper envelope.

5. The optical measurement method for the vibrational combustion response function of solid propellants according to claim 4, characterized in that, Determining the average burning rate of the propellant under vibration conditions based on the image of the propellant burning surface height changing over time includes: By subtracting the displacement of the vibration detector from the propellant burning surface displacement at the same moment, an image showing the change of the propellant's own burning surface height retreat over time can be obtained. The image of the change in the burn surface height retreat of the propellant itself over time is smoothed to obtain a smooth curve; The smooth curve is fitted, and the absolute value of the slope of the straight line obtained by fitting the smooth curve is determined to be the average burning rate of the propellant under vibration conditions.

6. An optical measurement apparatus of a vibration combustion response function of a solid propellant, for performing the optical measurement method of the vibration combustion response function of a solid propellant according to any one of claims 1 to 5, characterized by The device includes an excitation system, a vibration combustion support, an optical measurement system, and a processing module; The excitation system is equipped with a function generator (1), a power controller (2) and an exciter (3), wherein the power controller (2) is electrically connected between the function generator (1) and the exciter (3); The vibration combustion support consists of a propellant clamping part (4) and a vibration detector (5). The propellant clamping part (4) is fixedly connected to the vibration table surface of the exciter (3). The vibration detector (5) is a rigid thin sheet. The vibration detector (5) and the propellant strip (11) clamped by the propellant clamping part (4) are located on the same plane. The optical measurement system includes a laser (6), a high-speed camera (7), a filter (8), a telephoto macro lens (9), and a data acquisition module (10). The laser light from the laser (6) passes through the propellant strip (11) and the vibration detector (5) before entering the telephoto macro lens (9). The filter (8) is located on the side of the telephoto macro lens (9) located from the vibration detector (5). The telephoto macro lens (9) is connected to the high-speed camera (7), and the data acquisition module (10) is electrically connected to the high-speed camera (7). The processing module is electrically connected to the optical measurement system and is used to process the image data obtained by the optical measurement system and calculate the value of the solid propellant vibration combustion response function.

7. The optical measurement device of the solid propellant vibration combustion response function according to claim 6, characterized in that, The laser (6) is a 532nm laser, and the filter (8) is a 532nm filter.

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