Propellant burning surface testing method

Abstract

The invention relates to the technical field of propellant testing, in particular to a propellant burning surface testing method. The invention provides a propellant burning surface testing method. The propellant burning surface testing method comprises the following steps: constructing an X-ray imaging system based on an image intensifier and a high-speed camera, constructing a propellant burning surface testing system based on a double-view-angle X-ray imaging principle, establishing space alignment of double-view-angle image data and the like. By adopting the propellant burning surface test method provided by the invention, the problem that the positions of the two X-ray imaging systems are shifted due to vibration factors in an engine ignition test process can be effectively overcome, the acquired image space is ensured to be aligned, and the precision of subsequent two-dimensional image three-dimensional reconstruction is improved. A three-dimensional dynamic combustion surface retreating test of the solid rocket engine can be realized, and the accuracy of a test result is improved.

Description

Technical Field

[0001] This invention relates to the field of propellant testing technology, and more specifically to a method for testing the burning surface of a propellant. Background Technology

[0002] Current X-ray inspections of solid rocket motors are performed after propellant loading, using radiography or CT scans. This traditional CT imaging method cannot detect changes in the internal structure of the engine during combustion. During engine operation, defects such as holes and cracks in the propellant grain alter the combustion surface, preventing combustion according to the designed surface and causing the internal ballistic curve to deviate from design requirements. Furthermore, the high temperature, high pressure, and vibration within the combustion chamber can also create new defects in the propellant grain, altering the shape of the combustion surface. Existing technologies cannot monitor changes in the propellant combustion surface in real time, nor can they detect the generation and propagation of defects such as cracks during combustion, failing to meet the requirements of engine design units for accurate combustion profile testing during engine trials. The combustion surface regression process of a solid rocket motor directly determines its internal ballistic performance. Quantitative measurement of the combustion surface regression process can effectively improve the accuracy of internal ballistic prediction and plays a crucial role in engine design.

[0003] Currently, there are two main methods for testing the combustion surface of solid rocket motors: microwave testing and ultrasonic testing. Microwave testing is based on radio frequency (RF) measurement principles and involves researching combustion surface regression testing technology for solid rocket motors. It designs multi-band, multi-waveform test schemes based on the combustion surface regression attenuation characteristics, establishes corresponding RF links for testing, and scans and detects the combustion surface changes during solid rocket motor testing to obtain combustion surface regression test data. However, microwave testing can only be used for motors with fiberglass casings and cannot be used for motors with casings made of other materials.

[0004] The ultrasonic testing method involves mounting an ultrasonic probe on the outside of the engine casing and emitting ultrasonic waves at a certain trigger frequency toward the propellant charge. The ultrasonic waves pass through the casing, insulation layer, and propellant charge in sequence, propagating at the speed of sound within the charge. Upon reaching the combustion surface, they are reflected, and the reflected ultrasonic waves are still received by the probe. By measuring the round-trip propagation time of the ultrasonic waves in the propellant charge, the position parameters of the combustion surface can be determined. However, the ultrasonic testing method can only perform point tests and cannot perform tests along the entire circumference of the engine test location.

[0005] To address the shortcomings of the aforementioned propellant burn surface testing methods, this invention proposes a propellant burn surface testing method that can achieve three-dimensional dynamic burn surface regression testing of solid rocket engines, obtain accurate test data on combustion regression, accurately grasp the changing patterns of the propellant burn surface, establish an accurate combustion model, and provide basic experimental data for precise prediction and model correction of engine performance. Summary of the Invention

[0006] This invention proposes a propellant combustion surface testing method to solve the technical problems of the inability to detect the dynamic combustion surface of solid rocket engines in real time and the inaccuracy of such detection.

[0007] To achieve the above objectives, the present invention solves the above technical problems through the following technical solutions:

[0008] A method for testing the burning surface of a propellant, the method comprising the following steps:

[0009] S1: Construct an X-ray imaging system based on an image intensifier and a high-speed camera, wherein the image intensifier is coupled to the high-speed camera using the flange coupling distance test method;

[0010] S2: Construct a propellant burning surface testing system based on the principle of dual-view X-ray imaging. It is built using two sets of X-ray sources, image intensifiers and high-speed camera systems that are 90° apart to each other, so as to realize the imaging of the engine burning surface from two directions.

[0011] S3: Establish spatial alignment of dual-view image data. Markers are pasted on the surface of the engine, and the common marker points in the dual-view data are searched using the topological relationship of the marker center to achieve spatial alignment of the dual-view data.

[0012] The X-ray imaging system consists of an X-ray source, an image intensifier, and a high-speed camera.

[0013] The X-ray source emits X-rays, the image intensifier is used to receive the X-rays and enhance the brightness of the image, and the high-speed camera is used to receive visible light image signals.

[0014] The visible light image signal will be directly received by the high-speed camera. After receiving the signal, the high-speed camera will process it through a modulation circuit, converting it into a data electrical signal. Finally, it will be converted into a data stream that meets the interface communication protocol through a data interface and transmitted to the host computer for storage, processing, reconstruction, etc.

[0015] The dynamic testing system for the burning surface consists of two identical X-ray imaging systems based on image intensifiers and high-speed cameras, arranged at a 90° angle to each other.

[0016] The markers are affixed to the surface of the engine at the test location. The markers are located in the axial regions of the two X-ray imaging systems. By analyzing the topological relationship of the marker centers on the captured images, common marker points in the dual-view images are searched to achieve spatial alignment of the dual-view image data.

[0017] When the image intensifier is coupled to the high-speed camera, the optimal deployment distance for the high-speed camera is 10mm to 70mm, the center resolution is 34Lp / mm to 50Lp / mm, and the optimal flange fixing distance is 110mm to 170mm.

[0018] The inner diameter of the transmission space inside the flange ranges from 90mm to 110mm.

[0019] The flange is made of one of the following materials: engineering plastics, aluminum alloys, and Q235 steel, with Q235 steel being preferred.

[0020] Based on the implementation of the above technical solution, the present invention can achieve the following technical effects:

[0021] 1. This invention provides a propellant burning surface testing method, which uses two sets of image intensifiers and high-speed camera X-ray imaging systems arranged at a 90° angle to image the engine burning surface from two directions. This avoids superimposed imaging of engine structural information, which would cause feature occlusion, and enables three-dimensional dynamic burning surface regression testing of solid rocket engines.

[0022] 2. This invention provides a method for testing the propellant burning surface. The image intensifier and the high-speed camera are coupled using a flange coupling distance test method, which can ensure the accuracy of the coupling between the image intensifier and the high-speed camera and ensure the accuracy of the test results.

[0023] 3. This invention provides a propellant burning surface testing method, which uses X-ray detection technology to test the engine burning surface of all materials such as fiberglass, carbon fiber, and metal.

[0024] 4. This invention provides a method for testing propellant combustion surface. Markers are affixed to the engine surface, and the topological relationship between the centers of these markers is used to search for common marker points in both perspectives, achieving spatial alignment of the dual-view data. This effectively overcomes the positional shifts of the two X-ray imaging systems caused by vibration during engine ignition testing, ensuring spatial alignment of the acquired images and improving the accuracy of subsequent 3D reconstruction of the 2D images. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram illustrating the process of acquiring X-ray imaging images of the engine combustion surface provided by the present invention;

[0027] Figure 2 This is the experimental design diagram for testing the coupling distance between the image intensifier and the flange of the high-speed camera provided by this invention;

[0028] Figure 3 This is a schematic diagram of the coupling structure between the image enhancer and the high-speed camera provided by the present invention;

[0029] Figure 4 This is a schematic diagram of the orthogonal arrangement of the X-ray imaging system based on an image intensifier and a high-speed camera provided by the present invention;

[0030] Figure 5 This is a schematic diagram of the dual-view image spatial alignment mark provided by the present invention;

[0031] Figure 6 This is a design drawing of the dual-view X-ray burning surface dynamic testing system provided by the present invention. Detailed Implementation

[0032] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0033] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0034] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0035] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0036] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0037] The following is combined with Figures 1-6 This invention provides a detailed description of a propellant burn-out test method:

[0038] Combination Figure 1 As shown, in an embodiment of the present invention, a propellant burn-out testing system includes:

[0039] X-ray imaging system based on image intensifier and high-speed camera;

[0040] The dual-view X-ray dynamic testing system for burning surfaces consists of two identical X-ray imaging systems based on image intensifiers and high-speed cameras, arranged at a 90° angle to each other.

[0041] Furthermore, the X-ray imaging system based on the image intensifier and high-speed camera consists of an X-ray source, an image intensifier, and a high-speed camera.

[0042] Combination Figure 2 As shown, the image intensifier is coupled to the high-speed camera using the flange coupling spacing test method, which can ensure the coupling accuracy between the image intensifier and the high-speed camera and ensure the accuracy of the test results.

[0043] Furthermore, the X-ray source emits X-rays, the image intensifier is used to receive the X-rays and enhance the brightness of the image, and the high-speed camera is used to receive visible light image signals.

[0044] Furthermore, an image intensifier is used to convert the X-rays attenuated by the engine into visible light signals, and then a high-speed camera is used to convert the visible light signals into image data output.

[0045] Furthermore, the construction of the dual-view X-ray combustion surface dynamic testing system adopts two sets of X-ray source-image intensifier-high-speed camera systems at 90° to each other, which realizes imaging of the engine combustion surface from two directions, avoiding superimposed imaging of engine structural information and causing feature occlusion.

[0046] Combination Figure 4 , Figure 5 , Figure 6 As shown, the propellant burn-out test method includes the following steps:

[0047] S1: Construct an X-ray imaging system based on an image intensifier and a high-speed camera, wherein the image intensifier is coupled to the high-speed camera using the flange coupling distance test method;

[0048] S2: Construct a propellant burning surface testing system based on the principle of dual-view X-ray imaging. It is built using two sets of X-ray sources, image intensifiers and high-speed camera systems that are 90° apart to each other, so as to realize the imaging of the engine burning surface from two directions.

[0049] S3: Establish spatial alignment of dual-view image data. Markers are pasted on the surface of the engine, and the common marker points in the dual-view data are searched using the topological relationship of the marker center to achieve spatial alignment of the dual-view data.

[0050] Furthermore, in S1, the acquisition of X-ray imaging images of the engine combustion surface involves an X-ray source emitting rays, which are attenuated to varying degrees after passing through the solid rocket motor. The X-ray receiving screen of the image intensifier receives the attenuated X-rays and converts them into electronic image signals. These electronic image signals are transmitted to the intensification unit, where a strong electric field is applied to the electrons through its electron optical system. This energy is used to accelerate and focus the electron beam emitted from the photocathode onto a fluorescent screen, thereby enhancing the image brightness and causing the fluorescent screen to emit stronger light. After passing through an electron lens, the enhanced image data is emitted as a visible light image signal.

[0051] Furthermore, in the system, after the image intensifier and the high-speed camera are coupled, the visible light image signal emitted by the screen of the image intensifier will be directly received by the high-speed camera. After receiving the signal, the high-speed camera will process the visible light image data signal through a modulation circuit, converting it into a data electrical signal. Finally, it will be converted into a data stream that meets the interface communication protocol through the data interface and transmitted to the host computer for storage, processing, reconstruction, etc.

[0052] Furthermore, in step S3, lead markers are affixed to the surface of the engine at the test location. These markers are located along the axes of the two X-ray imaging systems. By searching the topological relationships of the marker centers in the captured images, a common marker point is found in both perspectives, achieving spatial alignment of the dual-view image data. Aligning the dual-view images effectively solves the problem of image misalignment caused by vibrations in the engine ignition test environment, improving the accuracy of subsequent 3D image reconstruction.

[0053] Combination Figure 2 , Figure 3 As shown, in S1, the image intensifier is coupled to the high-speed camera. The coupling between the image intensifier and the high-speed camera is performed using the flange coupling distance test method to determine relevant parameters such as imaging distance. The specific coupling steps are as follows:

[0054] ① Determine the optimal deployment distance for high-speed cameras to achieve the best imaging effect. Test the imaging results of high-speed cameras under different distance conditions, and find that the optimal deployment distance for high-speed cameras corresponding to the best imaging effect is 10mm to 70mm.

[0055] ② Determine the optimal parameters for the intensifier. Adjust the output image diameter of the intensifier to 25mm and the center resolution to 34Lp / mm~50Lp / mm.

[0056] ③ Determine the optimal flange fixing distance. A study of different flange fixing distances was conducted, and the optimal flange fixing distance was determined to be 110mm~170mm;

[0057] ④ Determine the flange diameter. Conduct comparative tests on the flange inner diameter, adjust different flange inner diameters and perform actual imaging tests to determine the flange inner diameter range to be 90mm~110mm.

[0058] ⑤ Determine the flange material. Experimental imaging processes were conducted using flanges of different material types. The material with the least impact on imaging was selected to achieve the best imaging effect. Q235 steel was ultimately chosen as the flange material. Engineering plastics, aluminum alloys, etc., can also be selected as flange materials.

[0059] After completing the above steps, the coupling process between the image intensifier and the high-speed camera is achieved.

[0060] Furthermore, S2 constructs a propellant burning surface testing system based on the dual-view X-ray imaging principle.

[0061] Combination Figure 4 As shown, a propellant burning surface testing system is constructed by arranging two sets of X-ray sources, image intensifiers, and high-speed camera systems at 90° orthogonal angles.

[0062] CT imaging requires acquiring projections from multiple viewpoints for reconstruction, primarily to avoid superimposed imaging of structural information from different parts of the object detected in a single viewpoint, which can cause feature occlusion and prevent reconstruction. Increasing the number of viewpoints effectively suppresses the occlusion problem of projection information from a single viewpoint.

[0063] This invention has completed the static test simulation verification of the engine profile under a single view. The system was used to collect projection data of the manufactured propellant grain from two mutually perpendicular directions. The reconstructed combustion surface image has a similarity of more than 95% with the actual object, which verifies the feasibility of the engine propellant combustion surface X-ray test method and test system.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A propellant burning surface testing method, characterized in that: The test method comprises the following steps: S1: Construct an X-ray imaging system based on an image intensifier and a high-speed camera, wherein the image intensifier is coupled to the high-speed camera using a flange coupling spacing test method; S2: Construct a propellant combustion surface test system based on the principle of dual-view X-ray imaging, using two sets of ray source-image intensifier-high-speed camera systems at 90 degrees to each other, to achieve imaging of the engine combustion surface from two directions; S3: Establish the spatial alignment of the dual-view image data, paste markers on the engine surface, and use the topological relationship of the marker center to search for the common marker points in the dual-view to achieve the spatial alignment of the dual-view data.

2. The propellant combustion surface testing method according to claim 1, characterized in that: The X-ray imaging system consists of an X-ray source, an image intensifier, and a high-speed camera.

3. The propellant combustion surface testing method according to claim 2, characterized in that: The X-ray source emits X-rays, the image intensifier is used to receive the X-rays and enhance the brightness of the image, and the high-speed camera is used to receive visible light image signals.

4. The propellant burning surface testing method according to claim 3, characterized in that: The visible light image signal will be directly received by the high-speed camera. After receiving it, the high-speed camera will decode the visible light image signal through the modulation circuit, convert it into a data electrical signal, and finally convert it into a data stream that meets the interface communication protocol through the data interface, and transmit it to the host computer for storage, processing, reconstruction, etc.

5. The propellant burning surface testing method according to claim 1, characterized in that: The combustion surface dynamic test system consists of two sets of X-ray imaging systems based on image intensifiers and high-speed cameras with exactly the same design, and the two systems are arranged at an angle of 90° to each other.

6. The propellant burning surface testing method according to claim 1, characterized in that: The markers are pasted on the surface of the engine tested position, and the markers are respectively located in the axis areas of the two sets of X-ray imaging systems. By searching for the topological relationship of the marker centers on the captured images, the common marking points in the dual perspectives are searched to achieve spatial alignment of the dual perspective image data.

7. The propellant combustion surface testing method according to claim 4, characterized in that: When the image intensifier is coupled to a high-speed camera, the optimal distance range for deploying the high-speed camera is 10 mm to 70 mm, the center resolution is 34 Lp / mm to 50 Lp / mm, and the optimal flange fixing distance range is 110 mm to 170 mm.

8. The propellant combustion surface testing method according to claim 7, characterized in that: The inner diameter of the transmission space inside the flange ranges from 90 mm to 110 mm.

9. The propellant combustion surface testing method according to claim 8, characterized in that: The material of the flange is selected from engineering plastics, aluminum alloy, and Q235 steel, preferably Q235 steel.

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