Three-dimensional chromatography test system and method for ignition process of aero-engine combustion chamber

Abstract

The invention relates to the technical field of aero-engine combustion chamber performance testing, in particular to a three-dimensional chromatography testing system and method for the ignition process of an aero-engine combustion chamber. The device is characterized by comprising a guide rail arranged on the periphery of an igniter of a combustion chamber, a plurality of imaging units are arranged on the guide rail, each imaging unit is composed of an imaging lens, a flexible optical fiber bundle and a four-degree-of-freedom sliding block, a high-speed camera is arranged corresponding to the flexible optical fiber bundle, and the high-speed camera is connected with a synchronous controller through a signal line. And the synchronous controller is connected with the igniter through a signal line. By introducing the flexible optical fiber bundle and the synchronous controller, the number of the high-speed cameras is reduced to one, so that the test cost is reduced, the problem of synchronous control of the high-speed cameras and the igniter is solved, and the synchronism of the high-speed chromatographic measurement test bed to the ignition process is guaranteed. Meanwhile, the imaging lens can be placed on the guide rail at any angle through the sliding block, and test operation is facilitated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of performance test of aero-engine combustion chamber, in particular to a three-dimensional tomography test system and method for ignition process of aero-engine combustion chamber. BACKGROUND

[0002] The aero-engine combustion chamber is one of the core components of the aero-engine, and is the heart of the aero-engine. The ignition performance, especially the high-altitude re-ignition performance, determines the flight envelope of the aircraft to some extent, and further affects the weight, cost, emission of the engine, and the safety of the aircraft, etc. The success or failure of the combustion chamber in the ignition process is mainly affected by the development of the initial flame kernel. Therefore, by studying the ignition process of the combustion chamber, the influence of the development of the initial flame kernel on the ignition performance can be understood, the ignition and extinction mechanism can be further understood, and then an effective method for improving the ignition performance of the combustion chamber can be found. At present, the research on the ignition process of the combustion chamber is mainly through the self-luminous flame, and the development state of the ignition process of the flame kernel is recorded by a high-speed camera. However, this method is limited to two-dimensional plane, that is, the two-dimensional development state of the ignition process of the flame kernel is obtained, and the combustion chamber is a three-dimensional object, so the development state of the flame kernel is also three-dimensional. The computer tomography technology is to record the two-dimensional projection images of the flame distributed at different angles by the cameras, and the three-dimensional distribution of the flame is obtained by processing the images by a reconstruction algorithm, so as to obtain the three-dimensional development state of the ignition process of the flame kernel. Since the 1980s, the tomography technology has been applied in the field of reburning diagnosis, so that the three-dimensional measurement of the high space-time resolution of the turbulent flame becomes possible.

[0003] The structure of the combustion chamber is complex and it is also an incomplete light-transmitting closed object, so it is difficult to implement the three-dimensional tomography measurement test of the combustion chamber. At the same time, since the ignition process of the combustion chamber is a transient development process, the high-speed camera and the igniter need to have synchronicity, that is, the first frame of picture taken by the high-speed camera is the moment when the igniter starts to discharge, and only in this way can the whole ignition process be shot. In addition, the arrangement position of the tomography lens is affected by the test scene, the tomography technology needs two-dimensional images at different angles for reconstruction analysis, and the cameras are large in volume and heavy in weight, so it is impossible to be placed at any angle, thereby increasing the measurement difficulty of the combustion chamber. SUMMARY

[0004] The present application aims to avoid the shortcomings of the prior art and provide a three-dimensional tomography test system and method for ignition process of aero-engine combustion chamber, which realizes the three-dimensional tomography test of the ignition process of the aero-engine combustion chamber and solves the problems of the prior art.

[0005] In order to achieve the above object, the technical scheme adopted by the present application is as follows: a three-dimensional tomography test system for an aero-engine combustion chamber ignition process, comprising a guide rail arranged outside an igniter of the combustion chamber, a plurality of imaging units arranged on the guide rail, the imaging unit being composed of an imaging lens, a flexible optical fiber bundle and a four-degree-of-freedom slider, a high-speed camera corresponding to the flexible optical fiber bundle, the high-speed camera being connected to a synchronous controller through a signal line, and the synchronous controller being connected to the igniter through a signal line.

[0006] The position of the high-speed camera and the flexible optical fiber bundle and the focusing of the lens are such that the light signal received by the high-speed camera is optimal, the imaging lens of the imaging unit is installed on the four-degree-of-freedom slider and is moved by sliding the four-degree-of-freedom slider to realize the relative position of the guide rail to the combustion chamber, the lens is used at an angle to shoot the combustion chamber ignition process, the imaging image of each lens is adjusted using an angle calibration block, the combustion chamber nozzle is located at the center of the image, and the angle calibration block shot by the high-speed camera is most clear in the picture; after each lens is calibrated, the synchronous controller is connected to the high-speed camera and the igniter using a signal line, and the synchronous controller is debugged so that the high-speed camera and the igniter can be triggered at the same time.

[0007] The imaging unit is arranged in nine groups, the imaging lens of the imaging unit is a lens for acquiring an image, the flexible optical fiber bundle is composed of a mother optical fiber at one end and a plurality of sub-optical fibers at the other end, the light signal of the sub-optical fiber is transmitted to the mother optical fiber through the optical fiber, and each sub-optical fiber corresponds to an imaging unit; the output end of the imaging lens is connected to the input end of the sub-optical fiber of the flexible optical fiber bundle; the high-speed camera is used to collect the light signal of the mother optical fiber and record the combustion chamber ignition process; the synchronous controller is used to control the high-speed camera and the combustion chamber igniter so that they are triggered at the same time to record the complete combustion chamber ignition process; the high-speed camera synchronously collects the ignition process flame signal on the sub-optical fiber, which is used for three-dimensional high-speed tomographic reconstruction of the combustion chamber ignition process.

[0008] The guide rail is an aluminum circular guide rail, the four-degree-of-freedom slider of the imaging unit is adjusted at an angle of 0° to 90° on the guide rail, so that the imaging lens on the four-degree-of-freedom slider can shoot flame images in four directions at the same time, and the guide rail has an angle scale of 0° to 360°, which is used to place the imaging unit at different positions to obtain flame images of the ignition process at different angles.

[0009] The combustion chamber is arranged at the geometric center of the guide rail and is a swirl combustion furnace with an optical window; the igniter is arranged inside the combustion chamber close to the inner wall side and is used to generate an initial fire core; the signal line is used to transmit the signal output by the synchronous controller to the high-speed camera and the igniter so that they are triggered synchronously.

[0010] The application also provides a test method of the three-dimensional tomography test system for the ignition process of the aero-engine combustion chamber. Step one, the three-dimensional tomography test system for the ignition process of the aero-engine combustion chamber is used, nine imaging units are respectively placed on the positions corresponding to the scales of 0°, 30°, 60°, 135°, 165°, 195°, 225°, 300° and 330° of the guide rail to obtain the angle images of the combustion chamber in nine directions during the ignition process, the position of the imaging lens on the guide rail relative to the combustion chamber and the shooting angle during the shooting of the ignition process of the combustion chamber are adjusted through the four-degree-of-freedom slider, the angle information and the ignition process images are recorded, and the focal length of each imaging lens is adjusted, the position of the imaging lens and the shooting angle are adjusted according to the real-time picture recorded by the high-speed camera through the angle calibration block, wherein the angle calibration block is placed in the center of the combustion chamber, and each imaging lens is calibrated in turn, so that the picture of the angle calibration block shot by the high-speed camera is the clearest, the imaging quality of the combustion chamber in each imaging lens shot by the high-speed camera is the best, and the combustion chamber is in the center of the image, that is, the imaging lens is adjusted to be the best; Step two, the output trigger signal of the synchronous controller is adjusted so as to synchronously trigger the high-speed camera and the igniter, and the first frame image recorded by the high-speed camera is taken as the time when the igniter releases the spark, that is, the synchronization is successful; Step three, the air inlet switch and the oil supply switch of the combustion chamber are turned on, the trigger button of the synchronous controller is pressed, the high-speed camera and the igniter work at the same time, the high-speed camera records the combustion chamber ignition process images of different angles relative to the center combustion chamber shot by the imaging lens, and the test is ended when the flame of the combustion chamber is stable, and the ignition process image data is saved; Step four, the three-dimensional reconstruction algorithm is used to perform three-dimensional reconstruction on the combustion chamber ignition process according to the recorded flame images of different directions, and the three-dimensional development process of the ignition process flame is obtained.

[0011] The three-dimensional reconstruction algorithm used in step four is used to perform three-dimensional reconstruction on the combustion chamber ignition process, and the specific steps are as follows: Firstly, the high-speed camera is used to collect the ignition process images of different directions, and the image noise reduction algorithm is used for noise reduction; Secondly, the flame images processed by the image noise reduction algorithm are input into the three-dimensional reconstruction algorithm, the three-dimensional reconstruction of the ignition process flame is performed, and the three-dimensional structure of the ignition process flame is obtained; Further, the three-dimensional reconstruction algorithm used in step four is the three-dimensional reconstruction using the algebraic reconstruction algorithm, and the specific steps are as follows: A two-dimensional matrix is used to represent the unknown discrete flame distribution inside the flame, The signal intensity value of each discrete area inside the flame, that is, the unknown number to be solved, Let represent the signal strength received by the camera. Assuming the signal generated by the flame propagates in a straight line and is received by the camera, and each camera pixel receives a beam of light, then the value of that pixel is equal to the sum of all signal strengths of that beam of light passing through the flame region. This yields the following system of equations: (1-1) Further expressed as (1-2) In the formula, n Representing the n Each projection angle A n This is the coefficient matrix under this projection angle, which is related to the angle of the projection relative to the original matrix. Therefore, other projection angles have similar equations in the form of equation set (1-2). Combining all the projection angle equations forms the overall equation set for tomographic reconstruction: (1-3) In the formula A A coefficient matrix containing all projection angles. b The pixel units, which include all sub-fibers, can be understood from the overall equations (1-3) to solve the three-dimensional tomographic reconstruction problem by knowing the multi-angle projection measurements. b Construct a coefficient matrix using the camera's azimuth angle. A ,beg x The process of solving the inverse matrix problem; Algebraic reconstruction methods are based on the idea of ​​numerical iteration, which first arbitrarily guesses the distribution of an unknown. x 0, substitute into the system of equations (1-3) to calculate the projection at each angle at this time. b 0, taking advantage of this time b 0 and the actual measured value b real The differences between them are corrected using the correction equation (1-4) to adjust for the unknowns. x The distribution of the problem is obtained by repeatedly performing the above process to obtain the final solution, which is the three-dimensional reconstruction result. (1-4) In the formula, k It is the number of iterations. a i It is the first in matrix A i One element, b i It is a true projection b The first in the matrix i 1 pixel, λ k It is the relaxation factor; the first term on the right side of the equation is the th... k The result of the iteration step, the second term is the result of the first step.k The result of calculating the difference between the projection and the true projection and assigning it to the pixel; Following the above method, a three-dimensional tomographic reconstruction program was developed and, in conjunction with a three-dimensional tomographic testing system, a three-dimensional reconstruction of the ignition process of an aero-engine combustion chamber was achieved.

[0012] The beneficial effects of this invention are as follows: This invention provides a three-dimensional tomographic testing system for the ignition process of an aero-engine combustor. By introducing a flexible fiber optic bundle and a synchronous controller, the number of high-speed cameras is reduced to one, thereby lowering the testing cost. It also solves the problem of synchronous control between the high-speed camera and the igniter, ensuring the synchronization of the high-speed tomographic measurement test bench with the ignition process. Furthermore, the imaging lens can be positioned at any angle on the guide rail by a slider, facilitating experimental operation. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structural principle of the present invention; Figure 2 This is the present invention. Figure 1 Schematic diagram of the center guide rail scale; Figure 3 This is a schematic diagram of the tomographic reconstruction principle of the present invention.

[0014] In the diagram, 1. Imaging lens, 2. Flexible fiber optic bundle, 3. High-speed camera, 4. Synchronization controller, 5. Guide rail, 6. Four-degree-of-freedom slider, 7. Combustion chamber, 8. Igniter, 9. Signal line. Detailed Implementation

[0015] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0016] To achieve the above objectives, the present invention provides the following specific embodiments: Figure 1 As shown, the three-dimensional tomographic test system for the ignition process of an aero-engine combustion chamber is characterized by including a guide rail 5 set around the igniter 8 in the combustion chamber 7. Multiple imaging units are set on the guide rail 5. Each imaging unit consists of an imaging lens 1, a flexible fiber bundle 2, and a four-degree-of-freedom slider 6. A high-speed camera 3 is set corresponding to the flexible fiber bundle 2. The high-speed camera 3 is connected to a synchronization controller 4 through a signal line 9. The synchronization controller 4 is connected to the igniter 8 through a signal line 9.

[0017] The high-speed camera 3 is positioned with the flexible optical fiber bundle female end and the lens focus, so that the light signal received by the high-speed camera 3 is optimal, the imaging lens 1 of the imaging unit is installed on the four-degree-of-freedom slider 6 and is moved by sliding the four-degree-of-freedom slider 6 to realize the position of the imaging lens 1 on the guide rail 5 relative to the combustion chamber 7, the angle calibration block is used to adjust the imaging image of each lens to make the combustion chamber nozzle be in the center of the image and make the angle calibration block imaged by the high-speed camera be clearest in the picture, after the calibration of each lens, the synchronous controller 4 is connected with the high-speed camera 3 and the igniter 8 by using the signal line, and the synchronous controller is debugged to make the high-speed camera and the igniter be triggered at the same time.

[0018] The imaging unit is arranged in nine groups, the imaging lens of the imaging unit is a lens for acquiring an image, the flexible optical fiber bundle is composed of a female optical fiber at one end and a plurality of sub optical fibers at the other end, the light signal of the sub optical fiber is transmitted to the female optical fiber through the optical fiber wire, and each sub optical fiber corresponds to an imaging unit arrangement; the output end of the imaging lens is connected with the input end of the sub optical fiber of the flexible optical fiber bundle; the high-speed camera is used for collecting the light signal of the female optical fiber and recording the combustion chamber ignition process; and the synchronous controller is used for controlling the high-speed camera and the combustion chamber igniter to be triggered at the same time, so that the complete combustion chamber ignition process is recorded; the high-speed camera synchronously collects the ignition process flame signal on the sub optical fiber, and is used for three-dimensional high-speed tomographic reconstruction of the combustion chamber ignition process.

[0019] The guide rail 5 is an aluminum circular guide rail, the four-degree-of-freedom slider of the imaging unit is adjusted at an angle of 0° to 90° on the guide rail, so that the imaging lens on the four-degree-of-freedom slider can simultaneously shoot flame images in four directions of up, down, left and right, and the guide rail is provided with an angle scale of 0° to 360°, which is used for placing the imaging unit at different positions to obtain flame images of the ignition process at different angles.

[0020] The combustion chamber 7 is arranged at the geometric center of the guide rail, the combustion chamber 7 is a swirl combustion furnace with an optical window; the igniter is arranged in the combustion chamber close to the inner wall side and is used for generating an initial fire core; and the signal line is used for transmitting the signal output by the synchronous controller to the high-speed camera and the igniter to make them be triggered synchronously.

[0021] An aviation engine combustion chamber ignition process three-dimensional tomographic testing method, which is characterized by comprising the following steps: Step one, using the aviation engine combustion chamber ignition process three-dimensional tomographic testing system, nine groups of imaging units are placed at positions corresponding to the scales of 0°, 30°, 60°, 135°, 165°, 195°, 225°, 300° and 330° on the guide rail to obtain angle images of the combustion chamber ignition process in nine directions, wherein the 0° scale line is aligned with the y axis, as shown in Figure 1 andFigure 2 As shown, the position of the imaging lens on the guide rail relative to the combustion chamber and the shooting angle when shooting the ignition process of the combustion chamber are adjusted by the four-degree-of-freedom slider, the angle information and the ignition process image are recorded, and the focal length of each imaging lens is adjusted according to the real-time picture recorded by the high-speed camera, and the position and shooting angle of the imaging lens are adjusted by the angle calibration block, wherein the angle calibration block is placed in the center of the combustion chamber and is calibrated in sequence for each imaging lens, so that the picture of the angle calibration block shot by the high-speed camera is the clearest, the imaging quality of the combustion chamber in each imaging lens shot by the high-speed camera is the best, and the combustion chamber is in the center of the image, that is, the imaging lens is adjusted to be the best; Step two, debug the output trigger signal of the synchronous controller, so that it synchronously triggers the high-speed camera and the igniter, and the synchronization criterion is that the first frame image recorded by the high-speed camera is the time when the spark of the igniter is released, that is, the synchronization is successful; Step three, open the air inlet and oil supply switch of the combustion chamber, press the trigger button of the synchronous controller, and the high-speed camera and the igniter work at the same time, the high-speed camera records the ignition process images of the combustion chamber at different angles relative to the center combustion chamber shot by the imaging lens, and the test is ended when the flame of the combustion chamber is stable, and the ignition process image data is saved; Step four, using the recorded flame images at different azimuth angles, using three-dimensional tomographic reconstruction algorithm to perform three-dimensional reconstruction on the ignition process of the combustion chamber, and obtaining the three-dimensional development process of the ignition process flame.

[0022] The three-dimensional reconstruction of the ignition process of the combustion chamber in step four using the three-dimensional tomographic reconstruction algorithm includes the following processes: Firstly, the ignition process images collected by the high-speed camera at different directions are denoised using an image denoising algorithm; Secondly, the flame images processed by the image denoising algorithm are input into the three-dimensional reconstruction algorithm, and the three-dimensional reconstruction of the ignition process flame is performed, and the three-dimensional structure of the ignition process flame is obtained; The three-dimensional reconstruction algorithm uses algebraic reconstruction algorithm for three-dimensional reconstruction, such as sparse angle algebraic reconstruction algorithm, multiplication algebraic reconstruction algorithm, large-scale parallel MART algorithm, and non-local average filtering MART algorithm, and the three-dimensional reconstruction process of the algebraic reconstruction algorithm includes: The tomographic reconstruction principle diagram is as shown in Figure 3 Figure 3 The two-dimensional matrix in the above formula represents the unknown discrete flame distribution inside the flame, is the signal intensity value of each discrete region inside the flame, that is, the unknown number to be solved, ​Let represent the signal strength received by the camera. Assuming that the signal generated by the flame propagates in a straight line and is received by the camera, and each camera pixel receives a beam of light, then the value of that pixel is equal to the sum of all signal strengths of the beam of light passing through the flame region. The following set of equations can be derived: (1) (1), The system of equations (1) can be represented by the following system of equations (2): (2), In the system of equations (2), n Representing the n Each projection angle A n This is the coefficient matrix under this projection angle, which is related to the angle of the projection relative to the original matrix. Therefore, other projection angles have similar equation sets (2). Combining all the projection angle equations forms the overall equation set (3) for tomographic reconstruction: (3), In the system of equations (3) A A coefficient matrix containing all projection angles. b This includes pixel units containing all sub-fibers. From the above equations, it can be seen that the essence of solving the 3D tomography reconstruction problem lies in knowing the measurements obtained from multi-angle projections. b Construct a coefficient matrix using the camera's azimuth angle. A ,beg x The process of solving the inverse matrix problem.

[0023] Algebraic reconstruction methods, based on the idea of ​​numerical iteration, are widely used in large-scale tomographic problems, achieving good reconstruction results using only a few projections from a few angles. The underlying idea is to first arbitrarily guess the distribution of an unknown variable. x 0, substitute into equation (3) to calculate the projection at each angle at this time. b 0, taking advantage of this time b 0 and the actual measured value b real The difference between them is corrected for by the following correction equation (4) to adjust for the unknowns. x The distribution of the solution is obtained by repeatedly performing the above process to obtain the final solution, which is the three-dimensional reconstruction result.

[0024] (4), In the modified equation (4), k It is the number of iterations. a i It is the first in matrix A i One element, b i It is a true projection b The first in the matrixi 1 pixel, λ k It is the relaxation factor. The first term on the right-hand side of the equation is the [missing term]. k The result of the iteration step, the second term is the result of the first step. k The result of calculating the difference between the projection and the true projection and assigning it to the pixel is the result of this step.

[0025] The three-dimensional tomographic reconstruction program written according to the above method, combined with the three-dimensional tomographic testing system in this case, can complete the three-dimensional reconstruction of the ignition process of the aero-engine combustion chamber.

[0026] This invention uses a flexible fiber bundle to transmit optical signals, enabling high-speed three-dimensional tomography testing with a single camera. It also employs a synchronization controller to synchronously trigger the high-speed camera and igniter, solving the synchronization problem between the high-speed camera and igniter during the ignition process. The flexible fiber bundle is combined with an imaging lens to achieve real-time high-speed transmission of multi-angle background schlieren images. The device is mounted on an adjustable rail via a four-degree-of-freedom slider, facilitating the adjustment of distance and angle during experiments.

[0027] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A three-dimensional tomographic test system for an aeroengine combustion chamber ignition process, characterized in that, The application relates to a device for recording the ignition process of a combustion chamber, comprising a guide rail arranged around the igniter of the combustion chamber, a plurality of imaging units arranged on the guide rail, the imaging unit being composed of an imaging lens, a flexible optical fiber bundle and a four-degree-of-freedom slider, a high-speed camera corresponding to the flexible optical fiber bundle, the high-speed camera being connected to a synchronous controller through a signal line, and the synchronous controller being connected to the igniter through a signal line.

2. A three-dimensional tomographic test system for the ignition process of a combustion chamber of a turbine engine as claimed in claim 1, characterized in that The high-speed camera and the position of the flexible optical fiber bundle mother end and the lens focusing make the light signal received by the high-speed camera optimal, the imaging lens of the imaging unit is installed on the four-degree-of-freedom slider and is moved to the position of the guide rail relative to the combustion chamber by sliding the four-degree-of-freedom slider, the imaging lens is adjusted by using an angle calibration block to make the combustion chamber nozzle located in the center of the image and make the angle calibration block shot by the high-speed camera most clear in the picture; After each lens is calibrated, the synchronous controller is connected to the high-speed camera and the igniter through signal lines, and the synchronous controller is debugged to make the high-speed camera and the igniter trigger at the same time.

3. A three-dimensional tomography test system for testing the ignition process of a combustion chamber of a gas turbine engine as set forth in either of claims 1 or 2, characterized in that The imaging unit is arranged in nine groups, the imaging lens of the imaging unit is a lens for acquiring an image, the flexible optical fiber bundle is composed of a mother optical fiber at one end and a plurality of sub optical fibers at the other end, the light signal of the sub optical fiber is transmitted to the mother optical fiber through an optical fiber wire, each sub optical fiber corresponds to an imaging unit, the output end of the imaging lens is connected to the input end of the sub optical fiber of the flexible optical fiber bundle, the high-speed camera is used for collecting the light signal of the mother optical fiber and recording the ignition process of the combustion chamber, and the synchronous controller is used for controlling the high-speed camera and the igniter of the combustion chamber so that the high-speed camera and the igniter trigger at the same time to record the complete ignition process of the combustion chamber. The high-speed camera synchronously collects the ignition process flame signals on the sub optical fibers and is used for three-dimensional high-speed tomographic reconstruction of the ignition process of the combustion chamber.

4. A three-dimensional tomographic test system for the ignition process of a combustion chamber of a turbine engine as set forth in claim 1, characterized in that, The guide rail is an aluminum circular guide rail, the four-degree-of-freedom slider of the imaging unit is adjusted at an angle of 0-90 degrees on the guide rail, the imaging lens on the four-degree-of-freedom slider can simultaneously shoot flame images in four directions, and the guide rail is provided with an angle scale of 0-360 degrees for placing the imaging unit at different positions to obtain ignition process flame images at different angles.

5. A three-dimensional tomographic test system for the ignition process of a combustion chamber of a turbine engine as set forth in claim 3, characterized in that: The combustion chamber is arranged at the geometric center of the guide rail and is a swirl combustion furnace with an optical window, the igniter is arranged in the combustion chamber close to the inner wall side and is used for generating an initial fire core, and the signal line is used for transmitting the signal output by the synchronous controller to the high-speed camera and the igniter to make the high-speed camera and the igniter trigger at the same time.

6. A method of testing a test system for three-dimensional tomographic testing of ignition processes in combustion chambers of aircraft engines according to one of claims 1 to 5, characterized in that: The device comprises the following steps: Step one, using the three-dimensional tomography test system of aero-engine combustion chamber ignition process, nine imaging units are placed on the corresponding scale 0°, 30°, 60°, 135°, 165°, 195°, 225°, 300°, 330° on the guide rail to obtain the angle image of the combustion chamber ignition process in nine directions, adjust the imaging lens through the four-degree-of-freedom slider, adjust the position of the guide rail relative to the combustion chamber and the shooting angle when shooting the combustion chamber ignition process, record the angle information and the ignition process image, and adjust the focal length of each imaging lens according to the real-time picture recorded by the high-speed camera through the angle calibration block, and adjust the imaging lens position and shooting angle; Wherein, the angle calibration block is placed in the center of the combustion chamber, and each imaging lens is calibrated in turn, so that the picture of the angle calibration block shot by the high-speed camera is the clearest, the imaging quality of the combustion chamber in each imaging lens shot by the high-speed camera is the best, and the combustion chamber is in the center of the image, that is, the imaging lens is adjusted to be the best; Step two, adjust the output trigger signal of the synchronous controller to make it trigger the high-speed camera and the igniter synchronously, and the synchronization criterion is that the first frame image recorded by the high-speed camera is the time when the igniter releases the spark, that is, the synchronization is successful; Step three, open the combustion chamber air inlet and oil supply switch, press the trigger button of the synchronous controller, the high-speed camera and the igniter work at the same time, the high-speed camera records the combustion chamber ignition process image shot by the imaging lens at different angles relative to the center combustion chamber, and the test is ended when the combustion chamber flame is stable, and the ignition process image data is saved; Step four, using the recorded flame images at different directions, using three-dimensional tomography reconstruction algorithm to reconstruct the three-dimensional structure of the combustion chamber ignition process; Firstly, the high-speed camera collects different direction ignition process images using image denoising algorithm for denoising; Secondly, the flame image after image denoising processing is input into three-dimensional reconstruction algorithm, and the three-dimensional structure of the ignition process flame is obtained.

7. The test assay method of claim 6, wherein, The three-dimensional reconstruction algorithm in step four is the three-dimensional reconstruction using algebraic reconstruction algorithm, and the specific steps are: A two-dimensional matrix is used to represent the unknown discrete flame distribution inside the flame, The signal strength value of each discrete region inside the flame, i.e. the unknown to be solved, represents the signal strength received by the camera. It is assumed that the signal generated by the flame propagates along a straight line and is received by the camera, and that each camera pixel receives a bundle of light rays. The value of each camera pixel is then equal to the sum of all signal strengths through which the bundle of light rays passes, resulting in a system of equations: （1-1）， Further represented as, （1-2）， wherein n represents the number of projection angles, n one projection angle, A n is the coefficient matrix at this projection angle, which is related to the angle of the projection relative to the original matrix, and thus other projection angles have similar equations (1-2) in form. Combining all projection angle equations together forms the total equation set for tomographic reconstruction: （1-3）， In the formula A The coefficient matrix containing all projection angles, b The pixel unit containing all sub-fibers, according to the total equation group (1-3), the essence of solving the three-dimensional tomographic reconstruction problem is to obtain b The coefficient matrix constructed by the azimuth angle of the camera A The matrix inverse problem solving process of x ; Algebraic reconstruction methods are based on the idea of ​​numerical iteration, which first arbitrarily guesses the distribution of an unknown. x 0, substitute into the system of equations (1-3) to calculate the projection at each angle at this time. b 0, taking advantage of this time b 0 and the actual measured value b real The differences between them are corrected using the correction equation (1-4) to adjust for the unknowns. x The distribution of the problem is obtained by repeatedly performing the above process to obtain the final solution, which is the three-dimensional reconstruction result. （1-4）， In the formula, k It is the number of iterations. a i It is the first in matrix A i One element, b i It is a true projection b The first in the matrix i 1 pixel, According to the above method, the three-dimensional tomography reconstruction program is written, and the three-dimensional tomography test system is used to realize the three-dimensional reconstruction of the aero-engine combustion chamber ignition process. k It is a relaxation factor; The first term on the right side of the equation is the result of the iteration of the step k for the pixel, and the second term is the result of distributing the difference between the calculated projection for the pixel in step k and the true projection to that pixel; ​

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