Liquid propellant atomization and combustion field synchronous observation system and analysis method

Abstract

The present application relates to a kind of liquid propellant atomization field, combustion field synchronous observation system and analysis method, solve the problem that existing visual observation technology exists synchronous shooting frequency division difficult, high synchronous time precision requirement, the present application is by setting up combustion shooting unit on the reflection light path of the half-transmission half-reflection mirror of optical path unit, setting up atomization shooting unit on the transmission light path of the half-transmission half-reflection mirror, the image of atomization field and combustion field is obtained simultaneously at the same shooting angle, by clock delay pulse signal generator as external clock simultaneously control the time sequence of first high-speed camera, image intensifier, second high-speed camera, and delay pulse signal generator as external trigger simultaneously control the shooting start time of first high-speed camera, second high-speed camera, so that both are started synchronously.

Description

Technical Field

[0001] This invention relates to observation and testing systems, specifically to a system and method for simultaneous observation and analysis of liquid propellant atomization and combustion fields. Background Technology

[0002] Atomization and combustion of liquid propellants are crucial processes in engine operation, directly impacting engine performance. Atomization is a prerequisite for combustion, which is the result of the combined effects of atomized mixing and the propellant's chemical properties. Existing research indicates that due to changes in the temperature and density of the combustion gases during liquid propellant combustion, the atomization morphology, droplet size, and velocity in the combustion chamber differ significantly from those observed under normal pressure or cold conditions. The atomization field distribution and atomization fineness directly affect propellant mixing, evaporation, and combustion efficiency. Conversely, the heat release and gas expansion generated during combustion lead to increases in temperature and pressure, which in turn affect atomization characteristics. Therefore, researching simultaneous observation techniques for the atomization and combustion fields of liquid propellants under combustion conditions, as well as the interaction between atomization and combustion, is of great significance for improving injector and engine performance.

[0003] Since the measurement targets are the atomization and combustion fields of the engine injectors, traditional contact measurements would severely interfere with the measured objects. Therefore, a non-contact optical diagnostic method is required. Furthermore, atomization and combustion interact with each other, necessitating simultaneous imaging and measurement within the same field of view. Secondly, the characteristic frequencies of the engine's atomization and combustion processes range from several thousand to tens of thousands of hertz, and the start-up process is also on the order of milliseconds. Therefore, the acquisition frequency of the measurement system must be above ten thousand hertz.

[0004] Current visualization observation techniques involve capturing images of the atomized droplet shadow and flame autofluorescence separately in the same field of view, or simultaneously capturing images in different fields of view. However, it is impossible to simultaneously capture images of the atomized droplet shadow and flame autofluorescence within the same field of view. Synchronous observation technology for liquid propellant atomization and combustion is extremely difficult to implement due to the challenges of frequency division during synchronous shooting and the high precision requirements for synchronization time. Currently, there is no complete observation system for simultaneously capturing the atomization and combustion fields within the same field of view under the high thermal radiation combustion state of liquid propellants. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problems of difficulty in synchronous shooting frequency division and high requirements for synchronization time accuracy in existing visualization observation technologies, and to provide a synchronous observation system and analysis method for liquid propellant atomization field and combustion field.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] A system for simultaneous observation of liquid propellant atomization and combustion fields is characterized by the following features:

[0008] It includes an optically observable combustion chamber, a fogging imaging unit, a combustion imaging unit, and an optical path unit;

[0009] The optically observable combustion chamber includes a window frame and quartz glass plates. The window frame has a through hole in the center for accommodating an engine injector. A rectangular groove is formed around the through hole. There are four quartz glass plates, which are located in the rectangular groove and are respectively arranged on the four sides of the rectangular groove, and the four quartz glass plates are connected end to end.

[0010] The optical path unit includes a xenon lamp and a point light source shaping aperture, a long-pass shadow filter, an incident convex lens, a semi-transparent mirror, an exit convex lens, a shadow transmission aperture, and a short-pass shadow filter, which are sequentially arranged on the xenon lamp's output optical path; the two opposing quartz glass plates in the optically observable combustion chamber are located on the optical path between the incident convex lens and the semi-transparent mirror.

[0011] The combustion imaging unit includes a first computer, a first high-speed camera, an image intensifier, a UV lens, a narrowband filter, and a clock delay pulse signal generator; the narrowband filter, UV lens, image intensifier, and first high-speed camera are sequentially arranged in the reflected light path of the semi-transparent mirror; the first computer is electrically connected to the first high-speed camera and is used to record and analyze the combustion field images captured by the first high-speed camera.

[0012] The atomization imaging unit includes a second computer, a time-delay pulse signal generator, and a visible light lens and a second high-speed camera sequentially arranged in the light path of the short-pass shadow filter. The second computer is electrically connected to the second high-speed camera and is used to record and analyze the atomization field images captured by the second high-speed camera.

[0013] The control terminal of the clock delay pulse signal generator is electrically connected to the first high-speed camera, the image intensifier, and the second high-speed camera, respectively; the control terminal of the delay pulse signal generator is electrically connected to the first high-speed camera and the second high-speed camera, respectively.

[0014] Furthermore, it also includes an aluminum gasket sealing strip; between the through hole and the rectangular groove of the window frame, a sealing groove is provided around the bottom of the rectangular groove and between the through hole and the quartz glass sheet. The cross-sectional shape of the aluminum gasket sealing strip is T-shaped, with the small end of the T-shape located in the sealing groove, one side of the large end abutting against the inner wall of the rectangular groove, and the other side abutting against the inner wall of the quartz glass sheet.

[0015] Furthermore, the aluminum gasket sealing strip and the sealing groove, as well as the aluminum gasket sealing strip and the quartz glass sheet, are bonded together using high-temperature resistant silicone sealant.

[0016] Furthermore, the semi-transparent mirror reflects light in the wavelength band less than 435nm and transmits light in the wavelength band greater than 435nm;

[0017] The long-pass shadow filter transmits light in the wavelength band greater than 450nm, while the short-pass shadow filter transmits light in the wavelength band less than 490nm.

[0018] Furthermore, it also includes a data acquisition unit and a dynamic pressure sensor;

[0019] The input terminals of the data acquisition unit are connected to the clock delay pulse signal generator and the delay pulse signal generator, respectively.

[0020] The dynamic pressure sensor is mounted on the optically observable combustion chamber and is used to collect pulsating pressure data. The dynamic pressure sensor is electrically connected to the input terminal of the data acquisition unit.

[0021] Furthermore, the narrowband filter is an OH narrowband filter or a CH narrowband filter. The OH narrowband filter transmits light in the 310nm band, and the CH narrowband filter transmits light in the 430nm band.

[0022] Furthermore, the clock delay pulse signal generator is model DG645, and the delay pulse signal generator is model DG535.

[0023] Meanwhile, this invention also provides a method for analyzing the atomization field and combustion field of liquid propellants, employing the aforementioned synchronous observation system for the atomization field and combustion field of liquid propellants. Its unique feature lies in the inclusion of the following steps:

[0024] S1. Place the engine injector in the through hole in the window frame, and start the engine injector and xenon lamp;

[0025] S2, the clock delay pulse signal generator acts as an external clock to simultaneously control the timing of the first high-speed camera, the image intensifier, and the second high-speed camera. The delay pulse signal generator acts as an external trigger to simultaneously control the shooting start time of the first high-speed camera and the second high-speed camera, so that the two start synchronously.

[0026] S3. The first high-speed camera transmits the N frames of combustion field images captured to the first computer; the second high-speed camera transmits the N frames of atomization field images captured to the second computer.

[0027] S4. The first computer and the second computer respectively divide one frame of the combustion field image and the atomization field image into multiple orthogonally distributed query regions, each query region having a pixel size of [missing information]. × ;

[0028] S5. Calculate the origin of one frame a(N,M) in the combustion field image and the atomization field image respectively. Near the origin ( The query area A is located in The query region B with the highest similarity cross-correlation coefficients :

[0029] ;

[0030] in: and For one pixel within the same query region relative to the origin ( The offset of ) and Represents query range B ( Relative query range A ( The offset of );

[0031] S6. Cross-correlation coefficients The query region A of the combustion field image and the atomization field image was obtained by subpixel interpolation. Subpixel displacement () );

[0032] S7. Query area A of the combustion field image and the atomization field image ( Subpixel displacement () Multiply by the ratio of the physical length corresponding to the pixel. and camera shooting frame rate The query regions A of the combustion field image and the atomization field image are obtained respectively. The velocity of particle clusters at position (V( , ),U( , )), where V( , ) represents the origin ( , The velocity U in the Y direction , ) represents the origin ( , The velocity in the X direction;

[0033] S8. Return to step S4 and calculate the next frame image until the query region A of N consecutive combustion field images and atomization field images is obtained. The velocity of particle clusters at position (V( , ),U( , ));

[0034] S9. Query region A for two adjacent frames of combustion field images and atomization field images ( The velocity of particle clusters at position (V( , ),U( , Cross-correlation calculations were performed to obtain N-1 velocity samples and their corresponding cross-correlation coefficients from the combustion field image and the atomization field image, respectively.

[0035] S10. Sort the N-1 velocity samples of the combustion field image and the atomization field image in descending order according to their corresponding cross-correlation coefficients. Select the top 10% of the velocity samples and average them to obtain the average velocity distribution of the combustion field image and the atomization field image over the N consecutive image time period. This will give you the velocity distribution map of the atomization field and the combustion field, and complete the analysis of the liquid propellant atomization field and combustion field.

[0036] Furthermore, the value of N is greater than or equal to 300.

[0037] Compared with the prior art, the beneficial effects of the present invention are:

[0038] (1) The liquid propellant atomization field and combustion field synchronous observation system provided by the present invention sets up a combustion imaging unit on the reflection optical path of the semi-transparent and semi-reflective mirror of the optical path unit, and sets up an atomization imaging unit on the transmission optical path of the semi-transparent and semi-reflective mirror, so that the images of the atomization field and the combustion field can be obtained simultaneously at the same shooting angle. The timing of the first high-speed camera, the image intensifier and the second high-speed camera are controlled simultaneously by the clock delay pulse signal generator as an external clock, and the shooting start time of the first high-speed camera and the second high-speed camera is controlled simultaneously by the delay pulse signal generator as an external trigger, so that the two start synchronously. This solves the technical problems of difficult frequency division and high accuracy requirements for synchronous shooting during shooting.

[0039] (2) In the liquid propellant atomization field and combustion field synchronous observation system provided by the present invention, the optically observable combustion chamber adopts aluminum gasket sealing strip and sealing groove to achieve sealing, and the sealing effect is further improved by high temperature resistant silicone sealant.

[0040] (3) The liquid propellant atomization field and combustion field synchronous observation system provided by the present invention is also equipped with a data acquisition unit and a dynamic pressure sensor, which can record the pulsating pressure data in the optically observable combustion chamber and the signal data of the clock delay pulse signal generator and the delay pulse signal generator in real time, providing data support for subsequent data analysis.

[0041] (4) The narrowband filter in the liquid propellant atomization field and combustion field synchronous observation system provided by the present invention is an OH narrowband filter or a CH narrowband filter. The OH narrowband filter allows light with a wavelength of 310nm to pass through, and the CH narrowband filter allows light with a wavelength of 430nm to pass through. It can filter out light of other wavelengths generated during the combustion process, and thus obtain OH-based images and CH-based images of the combustion field flame respectively.

[0042] (5) In the liquid propellant atomization field and combustion field synchronous observation system provided by the present invention, the long-pass shadow filter transmits light in the band greater than 450nm, and the short-pass shadow filter transmits light in the band less than 490nm, so that light in the band between 450nm and 490nm enters the second high-speed camera. In this band, the blackbody radiation intensity of kerosene soot is relatively weak and is non-parallel light, while the spectral intensity of xenon lamp is relatively strong in this band, and the signal-to-noise ratio during shooting can reach more than 20 times. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of an embodiment of a liquid propellant atomization field and combustion field synchronous observation system according to the present invention;

[0044] Figure 2 This is a comparison chart of the spectral radiance curves of a 30W tritium lamp, a 75W xenon lamp, a 150W xenon lamp, a 450W xenon lamp, a 100W bromine-tungsten lamp, and a 150W bromine-tungsten lamp, in an embodiment of a liquid propellant atomization field and combustion field synchronous observation system of the present invention.

[0045] Figure 3 This is a comparison of the blackbody radiation spectral intensity in the 450nm-490nm band and the 570nm-610nm band at a temperature of 3000K in an embodiment of the synchronous observation system for liquid propellant atomization field and combustion field of the present invention.

[0046] Figure 4 This is a schematic diagram of the clock signals of the first high-speed camera, image intensifier, and second high-speed camera in an embodiment of a synchronous observation system for liquid propellant atomization field and combustion field of the present invention.

[0047] Figure 5 This is a three-dimensional structural diagram of an optically observable combustion chamber in an embodiment of a liquid propellant atomization field and combustion field synchronous observation system of the present invention;

[0048] Figure 6 This is a schematic diagram of the cooperation between the sealing groove and the aluminum gasket sealing strip of the optically observable combustion chamber in an embodiment of a liquid propellant atomization field and combustion field synchronous observation system of the present invention;

[0049] Figure 7 This is a velocity distribution diagram of the atomization field and combustion field in an embodiment of a liquid propellant atomization field and combustion field synchronous observation system of the present invention.

[0050] The annotations in the attached figures are explained as follows:

[0051] 1- Clock delay pulse signal generator, 2- First high-speed camera, 3- Image intensifier, 4- UV lens, 5- Narrowband filter, 6- Second high-speed camera, 7- Delay pulse signal generator, 8- Data acquisition unit, 9- First computer, 10- Second computer, 11- Optically observable combustion chamber, 111- Quartz glass plate, 112- Window frame, 113- Aluminum gasket sealing strip; 12- Dynamic pressure sensor, 13- Xenon lamp, 14- Incident convex lens, 15- Exit convex lens, 16- Point light source shaping aperture, 17- Short-pass shadow filter, 18- Semi-transparent mirror, 19- Shadow transmission aperture, 20- Long-pass shadow filter, 21- Visible light lens. Detailed Implementation

[0052] The present invention will be further described below with reference to the accompanying drawings and exemplary embodiments.

[0053] Reference Figures 1-7 The present invention provides a liquid propellant atomization field and combustion field synchronous observation system, which includes an optically observable combustion chamber 11, an atomization imaging unit, a combustion imaging unit, and an optical path unit.

[0054] The structure of the optically observable combustion chamber 11 is as follows: Figure 5 As shown, the device includes a window frame 112 and four quartz glass plates 111. The window frame 112 has a central through-hole for accommodating an engine injector, and a rectangular groove surrounds the through-hole. Four quartz glass plates 111 are located within the rectangular groove and positioned on its four sides, end-to-end, enclosing the central through-hole of the window frame 112 for easy observation. All quartz glass plates 111 are made of high-pressure resistant quartz glass and can withstand a chamber pressure of 12 MPa.

[0055] To ensure a seal, such as Figure 6 As shown, a sealing groove is provided between the through hole and the rectangular groove in the window frame 112, around the bottom of the rectangular groove and located between the through hole and the quartz glass sheet 111. An aluminum gasket sealing strip 113 with a T-shaped cross-section is provided within the sealing groove, with the smaller end of the T-shape located inside the sealing groove, one side of the larger end abutting against the inner wall of the rectangular groove, and the other side abutting against the inner wall of the quartz glass sheet 111. To further improve the sealing effect, the aluminum gasket sealing strip 113 is bonded to the sealing groove, and to the quartz glass sheet 111, using high-temperature resistant silicone sealant. The greater the internal pressure on the quartz glass sheet 111, the tighter the aluminum gasket sealing strip 113 adheres to it. This sealing structure also ensures that the quartz glass sheet 111 is subjected to uniform stress, thus improving reliability.

[0056] The optical path unit includes a xenon lamp 13 and a point light source shaping aperture 16, a long-pass shadow filter 20, an incident convex lens 14, a semi-transparent mirror 18, an exit convex lens 15, a shadow transmission aperture 19, and a short-pass shadow filter 17, which are sequentially arranged on the optical path of the xenon lamp 13. The two opposing quartz glass plates 111 in the optically observable combustion chamber 11 are located on the optical path between the incident convex lens 14 and the semi-transparent mirror 18.

[0057] In this embodiment, the xenon lamp 13 has a power of 450W and is used to emit xenon light. After passing through the point light source shaping hole 16, the diffused xenon light is shaped into a point light source, which then reaches the long-pass shadow filter 20, which is used to filter out short-wavelength light and only allows light with wavelengths greater than 450nm to pass through. The incident convex lens 14 diverges the point light emitted from the long-pass shadow filter 20 into parallel light and sends it into the optically observable combustion chamber 11. Then, the parallel light and the light emitted from the combustion field in the optically observable combustion chamber 11 reach the semi-transparent mirror 18, which reflects light with wavelengths less than 435nm and transmits light with wavelengths greater than 435nm. Thus, the light emitted from the optically observable combustion chamber 11 is split into two paths: one path of reflected light enters the combustion imaging unit, and one path of transmitted light enters the atomization imaging unit. Parallel light transmitted from the semi-transparent mirror 18 and light emitted from the combustion field within the optically observable combustion chamber 11 are both fed into the exiting convex lens 15. The exiting convex lens 15 converges this light onto the shadow transmission aperture 19, which is used to block light generated by combustion that is not parallel to the light path, thereby improving the signal-to-noise ratio during imaging. Meanwhile, the short-pass shadow filter 17 is used to filter out long-wavelength light, allowing only light with wavelengths less than 490nm to pass through.

[0058] Although the shadow aperture 19 provides some obstruction, a small amount of thermal radiation from the combustion field can still pass through it and reach the CMOS sensor of the second high-speed camera 6. According to test results, when the flame temperature is 3000K, the long-pass shadow filter 20 is set to 570nm, and the short-pass shadow filter 17 is set to 610nm, the second high-speed camera 6 can still capture light signals during combustion experiments without the xenon lamp 13 on. The spectral radiance intensity is approximately 15% of that with the xenon lamp 13 on, and the signal-to-noise ratio is 6.67. The main source of thermal radiation is carbon soot, which can be approximated as a blackbody. Based on Wien's displacement law for blackbody radiation:

[0059] ;

[0060] in: λ is the peak wavelength of blackbody radiation. Its absolute temperature, Thermodynamic temperature;

[0061] It can be seen that when the temperature of the soot is 3000K, the peak wavelength of the thermal radiation spectrum is 965.87nm. The thermal radiation energy decreases sequentially in bands far from this peak wavelength. The formulas for calculating energy with respect to temperature and wavelength are as follows:

[0062] ;

[0063] in: The first radiation constant according to Planck's formula is... The second radiation constant according to Planck's formula is...

[0064] It is a natural constant. The energy emitted by a blackbody per unit wavelength wavelength;

[0065] =3.743*10⁸ W•μ / m 2 , =1.4387*104μm / K.

[0066] According to the above formula, when the combustion temperature is 3000K, the light intensity in the 450nm-490nm band does not exceed 40% of that in the 570nm-610nm band. Figure 2 It can be seen that, in this wavelength range, the 450W xenon lamp 13 has a stronger spectral radiance intensity compared to other light sources. Figure 3 In the spectrum, E1 represents the blackbody radiation intensity in the 570nm-610nm band, and E2 represents the blackbody radiation intensity in the 450nm-490nm band. Figure 3 It can be seen that by changing the band combination of the long-pass shadow filter 20 and the short-pass shadow filter 17 from 570nm-610nm to 450nm-490nm, the signal-to-noise ratio of the fog field can be increased by at least 20 times.

[0067] The combustion imaging unit includes a first computer 9, a clock delay pulse signal generator 1, and a narrowband filter 5, a UV lens 4, an image intensifier 3, and a first high-speed camera 2, which are sequentially arranged on the reflected light path of the semi-transparent mirror 18. The first computer 9 is electrically connected to the first high-speed camera 2 and is used to record and analyze the combustion field images captured by the first high-speed camera 2.

[0068] Narrowband filter 5 can be either an OH narrowband filter or a CH narrowband filter. These two filters allow light in the 310nm and 430nm bands, respectively, reflected by the semi-transparent mirror 18. These two bands correspond to the OH-based and CH-based images of the combustion field, respectively. The emission intensity of the 310nm OH radicals is closely related to the combustion temperature and reaction rate, representing the burned zone of the combustion reaction in the combustion field. It is concentrated at the flame front and can determine the flame structure and location. The 430nm CH radicals represent the reaction zone of combustion, a region where the temperature rises rapidly and the reaction is intense, producing free radicals. The appropriate narrowband filter 5 can be selected according to the observation requirements to capture the corresponding combustion field image.

[0069] The UV lens 4 can image the ultraviolet light transmitted through the narrow-band filter 5 onto the fluorescent screen of the image intensifier 3. The image intensifier 3 converts the ultraviolet light into visible light for imaging and amplifies the brightness. Then, the first high-speed camera 2 records the combustion field image formed by the image intensifier 3.

[0070] The fogging imaging unit includes a second computer 10, a delayed pulse signal generator 7, and a visible light lens 21 and a second high-speed camera 6 arranged sequentially on the light path of the short-pass shadow filter 17. The second computer 10 is electrically connected to the second high-speed camera 6 and is used to record and analyze the fogging field images captured by the second high-speed camera 6.

[0071] The optical path unit has already enabled the simultaneous acquisition of images of the atomization field and the combustion field from the same shooting angle. To achieve synchronous shooting by the two high-speed cameras, the control terminals of the clock delay pulse signal generator 1 are electrically connected to the first high-speed camera 2, the image intensifier 3, and the second high-speed camera 6, respectively. The control terminals of the delay pulse signal generator 7 are electrically connected to both the first high-speed camera 2 and the second high-speed camera 6, respectively. The clock delay pulse signal generator 1 acts as an external clock to simultaneously control the timing of the first high-speed camera 2, the image intensifier 3, and the second high-speed camera 6, while the delay pulse signal generator 7 acts as an external trigger to simultaneously control the shooting start time of both the first high-speed camera 2 and the second high-speed camera 6, enabling them to start synchronously. In this embodiment, the clock delay pulse signal generator 1 is a DG645, and the delay pulse signal generator 7 is a DG535. Figure 4 It can be seen that the clock signal gate width of image intensifier 3 is located within the gate width of the first high-speed camera 2 and the second high-speed camera 6. During shooting, the delay pulse signal generator 7 sends a TTL signal to trigger the two high-speed cameras and make them start synchronously.

[0072] To provide data support for subsequent data analysis, a data acquisition unit 8 and a dynamic pressure sensor 12 are also included. The input terminals of the data acquisition unit 8 are electrically connected to the clock delay pulse signal generator 1 and the delay pulse signal generator 7, respectively. The dynamic pressure sensor 12 is installed on the optically observable combustion chamber 11 and is used to collect pulsating pressure data. The dynamic pressure sensor 12 is electrically connected to the input terminal of the data acquisition unit 8. In this way, the data acquisition unit 8 can record in real time the pulsating pressure data in the optically observable combustion chamber 11, the clock signal data of the clock delay pulse signal generator 1, and the trigger signal data of the delay pulse signal generator 7.

[0073] This invention also provides a method for analyzing the atomization field and combustion field of liquid propellants, employing the aforementioned synchronous observation system for the atomization field and combustion field of liquid propellants, comprising the following steps:

[0074] S1. Place the engine injector in the through hole of the window frame 112, and start the engine injector and xenon lamp 13;

[0075] S2, the clock delay pulse signal generator 1 acts as an external clock to control the timing of the first high-speed camera 2, the image intensifier 3, and the second high-speed camera 6. The delay pulse signal generator 7 acts as an external trigger to control the shooting start time of the first high-speed camera 2 and the second high-speed camera 6, so that the two start synchronously.

[0076] S3. The first high-speed camera 2 transmits the captured N frames of combustion field images to the first computer 9; the second high-speed camera 6 transmits the captured N frames of atomization field images to the second computer 10.

[0077] S4, the first computer 9 and the second computer 10 respectively divide one frame of the combustion field image and the atomization field image into multiple orthogonally distributed query regions, each query region having a pixel size of [missing information]. × ;

[0078] in The values ​​for all of them are less than or equal to 20;

[0079] S5. Calculate the origin of one frame a(N,M) in the combustion field image and the atomization field image respectively. Near the origin ( The query area A is located in The query region B with the highest similarity cross-correlation coefficients :

[0080] ;

[0081] in: and For one pixel within the same query region relative to the origin ( The offset of ) and Represents query range B ( Relative query range A ( The offset of );

[0082] S6. Cross-correlation coefficients The query region A of the combustion field image and the atomization field image was obtained by subpixel interpolation. Subpixel displacement () );

[0083] S7. Query area A of the combustion field image and the atomization field image ( Subpixel displacement () Multiply by the ratio of the physical length corresponding to the pixel. and camera shooting frame rate The query regions A of the combustion field image and the atomization field image are obtained respectively. The velocity of particle clusters at position (V( , ),U( , )), where V( , ) represents the origin ( , The velocity U in the Y direction , ) represents the origin ( , The velocity in the X direction;

[0084] S8. Return to step S4 and calculate the next frame image until the query region A of N consecutive combustion field images and atomization field images is obtained. The velocity of particle clusters at position (V( , ),U( , ));

[0085] S9. Query region A for two adjacent frames of combustion field images and atomization field images ( The velocity of particle clusters at position (V( , ),U( , Cross-correlation calculations were performed to obtain N-1 velocity samples and their corresponding cross-correlation coefficients from the combustion field image and the atomization field image, respectively.

[0086] S10. Sort the N-1 velocity samples of the combustion field image and the atomization field image in descending order according to their corresponding cross-correlation coefficients. Select the top 10% of the velocity samples and average them to obtain the average velocity distribution of the combustion field image and the atomization field image over the N consecutive image time period. This will give you the velocity distribution map of the atomization field and the combustion field, and complete the analysis of the liquid propellant atomization field and combustion field.

[0087] To ensure the accuracy of the average velocity distribution, the value of N should not be too small. In this embodiment, the value of N is greater than or equal to 300, specifically 401.

[0088] The velocity distribution diagrams of the atomization field and combustion field are shown below. Figure 7 As shown in the figure, the red arrows represent the velocity of microparticles in the combustion field, and the blue arrows represent the velocity of microparticles in the atomization field.

[0089] The embodiments described above are merely illustrative of specific implementations of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A system for simultaneous observation of liquid propellant atomization field and combustion field, characterized in that: Includes an optically observable combustion chamber (11), a fogging imaging unit, a combustion imaging unit, and an optical path unit; The optically observable combustion chamber (11) includes a window frame (112) and quartz glass plates (111). The window frame (112) has a through hole in the center for accommodating an engine injector, and a rectangular groove is formed around the through hole. There are four quartz glass plates (111), which are located in the rectangular groove and are respectively arranged on the four sides of the rectangular groove, and the four quartz glass plates (111) are connected end to end. The optical path unit includes a xenon lamp (13) and a point light source shaping hole (16), a long-pass shadow filter (20), an incident convex lens (14), a semi-transparent mirror (18), an exit convex lens (15), a shadow transmission hole (19), and a short-pass shadow filter (17) arranged sequentially on the output optical path of the xenon lamp (13); the two opposing quartz glass plates (111) in the optically observable combustion chamber (11) are located on the optical path between the incident convex lens (14) and the semi-transparent mirror (18); The combustion imaging unit includes a first computer (9), a first high-speed camera (2), an image intensifier (3), a UV lens (4), a narrowband filter (5), and a clock delay pulse signal generator (1); the narrowband filter (5), UV lens (4), image intensifier (3), and first high-speed camera (2) are sequentially arranged on the reflected light path of the semi-transparent mirror (18); the first computer (9) is electrically connected to the first high-speed camera (2) and is used to record and analyze the combustion field images captured by the first high-speed camera (2); The atomization imaging unit includes a second computer (10), a delayed pulse signal generator (7), and a visible light lens (21) and a second high-speed camera (6) arranged sequentially on the light path of the short-pass shadow filter (17). The second computer (10) is electrically connected to the second high-speed camera (6) and is used to record and analyze the atomization field images captured by the second high-speed camera (6). The control terminal of the clock delay pulse signal generator (1) is electrically connected to the first high-speed camera (2), the image intensifier (3), and the second high-speed camera (6), respectively; the control terminal of the delay pulse signal generator (7) is electrically connected to the first high-speed camera (2) and the second high-speed camera (6), respectively.

2. The synchronous observation system for liquid propellant atomization field and combustion field according to claim 1, characterized in that: Also includes an aluminum gasket sealing strip (113); Between the through hole and the rectangular groove of the window frame (112), a sealing groove is provided around the bottom of the rectangular groove and between the through hole and the quartz glass sheet (111). The cross-sectional shape of the aluminum gasket sealing strip (113) is T-shaped, with the small end of the T-shape located in the sealing groove, one side of the large end abutting against the inner wall of the rectangular groove, and the other side abutting against the inner wall of the quartz glass sheet (111).

3. The synchronous observation system for liquid propellant atomization field and combustion field according to claim 2, characterized in that: The aluminum gasket sealing strip (113) and the sealing groove, as well as the aluminum gasket sealing strip (113) and the quartz glass sheet (111), are bonded together by high-temperature resistant silicone sealant.

4. The liquid propellant atomization field and combustion field synchronous observation system according to claim 3, characterized in that: The semi-transparent and semi-reflective mirror (18) reflects light with a wavelength less than 435nm and transmits light with a wavelength greater than 435nm. The long-pass shadow filter (20) transmits light in the wavelength band greater than 450nm, and the short-pass shadow filter (17) transmits light in the wavelength band less than 490nm.

5. The synchronous observation system for liquid propellant atomization field and combustion field according to claim 1, characterized in that: It also includes a data acquisition unit (8) and a dynamic pressure sensor (12); The input terminals of the data acquisition unit (8) are electrically connected to the clock delay pulse signal generator (1) and the delay pulse signal generator (7), respectively. The dynamic pressure sensor (12) is installed on the optically observable combustion chamber (11) and is used to collect pulsating pressure data. The dynamic pressure sensor (12) is electrically connected to the input end of the data acquisition unit (8).

6. The synchronous observation system for liquid propellant atomization field and combustion field according to claim 5, characterized in that: The narrowband filter (5) is an OH narrowband filter or a CH narrowband filter. The OH narrowband filter transmits light in the 310nm band, and the CH narrowband filter transmits light in the 430nm band.

7. The synchronous observation system for liquid propellant atomization field and combustion field according to claim 6, characterized in that: The clock delay pulse signal generator (1) is model DG645, and the delay pulse signal generator (7) is model DG535.

8. A method for analyzing the atomization field and combustion field of liquid propellant, employing a synchronous observation system for the atomization field and combustion field of liquid propellant as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Place the engine injector in the through hole of the window frame (112) and start the engine injector and xenon lamp (13). S2, the clock delay pulse signal generator (1) acts as an external clock to simultaneously control the timing of the first high-speed camera (2), the image intensifier (3), and the second high-speed camera (6), and the delay pulse signal generator (7) acts as an external trigger to simultaneously control the shooting start time of the first high-speed camera (2) and the second high-speed camera (6), so that the two start synchronously. S3. The first high-speed camera (2) transmits the captured N frames of combustion field images to the first computer (9); the second high-speed camera (6) transmits the captured N frames of atomization field images to the second computer (10); S4. The first computer (9) and the second computer (10) divide one frame of the combustion field image and the atomization field image into multiple orthogonally distributed query regions, each query region having a pixel size of [missing information]. × ; S5. Calculate the origin of one frame a(N,M) in the combustion field image and the atomization field image respectively. Near the origin ( The query area A is located in The query region B with the highest similarity cross-correlation coefficients : ； in: and For one pixel within the same query region relative to the origin ( The offset of ) and Represents query range B ( Relative query range A ( The offset of ); S6. Cross-correlation coefficients The query region A of the combustion field image and the atomization field image was obtained by subpixel interpolation. Subpixel displacement () ); S7. Query area A of the combustion field image and the atomization field image ( Subpixel displacement () Multiply by the ratio of the physical length corresponding to the pixel. and camera shooting frame rate The query regions A of the combustion field image and the atomization field image are obtained respectively. The velocity of particle clusters at position (V( , ),U( , )), where V( , ) represents the origin ( , The velocity U in the Y direction , ) represents the origin ( , The velocity in the X direction; S8. Return to step S4 and calculate the next frame image until the query region A of N consecutive combustion field images and atomization field images is obtained. The velocity of particle clusters at position (V( , ),U( , )); S9. Query region A for two adjacent frames of combustion field images and atomization field images ( The velocity of particle clusters at position (V( , ),U( , Cross-correlation calculations were performed to obtain N-1 velocity samples and their corresponding cross-correlation coefficients from the combustion field image and the atomization field image, respectively. S10. Sort the N-1 velocity samples of the combustion field image and the atomization field image in descending order according to their corresponding cross-correlation coefficients. Select the top 10% of the velocity samples and average them to obtain the average velocity distribution of the combustion field image and the atomization field image over the N consecutive image time period. This will give you the velocity distribution map of the atomization field and the combustion field, and complete the analysis of the liquid propellant atomization field and combustion field.

9. The method for analyzing the atomization field and combustion field of liquid propellant according to claim 8, characterized in that: The value of N is greater than or equal to 300.

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