Blade heat conduction analysis method based on electron linear accelerator CT system

Abstract

The invention discloses a blade heat conduction analysis method based on an electron linear accelerator CT system, and the method comprises the steps: carrying out the bright / dark field correction of a CT imaging system after the electron linear accelerator CT system is preheated and aged; performing cone beam scanning on the to-be-detected blade to obtain a DR scanning data set of the blade; reconstructing the DR scanning data set of the workpiece into a two-dimensional CT fault data set of the blade and a three-dimensional voxel model of the blade by using an image reconstruction system; any two layers of parallel two-dimensional fault diagrams of the blade are designated as inlet and outlet positions of thermal conductivity analysis, and a region range of thermal conductivity analysis is generated; setting a thermal conductivity parameter of a blade material and a relative temperature difference between an inlet position and an outlet position, setting a convergence error and the maximum number of iterations, and automatically analyzing the thermal conductivity of the blade to form a convergence graph; the thermal conductivity analysis result is displayed, and the detection requirements for the large-size aero-engine turbine blade complex three-dimensional structure and thermal conductivity analysis are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of accelerators, and in particular relates to a blade heat conduction analysis method based on an electron linear accelerator CT system. Background Art

[0002] Thermal conductivity, also known as "thermal conductivity coefficient", is a measure of a material's ability to conduct heat. Its symbol is λ or K. Thermal conductivity is defined as the amount of heat transferred from one plane to another in one second, perpendicular to the direction of heat conduction, perpendicular to the direction of heat conduction, and with an area of ​​1 square meter. If the temperature difference between the two planes is 1K, the unit of thermal conductivity is watt-meter. -1 ·open -1 (W·m -1 ·K -1 ).

[0003] Turbine blades, considered core components of aircraft engines, are widely used in aviation, aerospace, weapons, and other fields. Heat transfer within turbine blades involves both fluid-solid coupled heat transfer (i.e., intense convection between the blades and external high-temperature combustion gases and internal cooling airflow), and heat conduction caused by temperature differences within the solid blades. During the blade forming process, defects such as inclusions, cracks, and holes may form within the blades. X-ray inspection is significantly affected by the complex structure of the workpiece and cannot effectively detect internal defects. Industrial CT can effectively detect defects such as inclusions, cracks, and holes within the blades. However, for large-scale turbine blades, CT inspection requires the use of an accelerator as the radiation source.

[0004] Electron linear accelerator CT technology has been used since the 1980s to inspect the quality of aerospace charge and detect defects such as debonding and porosity within solid rocket motors. However, research has primarily focused on the development and application of electron linear accelerator CT equipment, while there has been a lack of research on blade thermal conductivity analysis methods based on electron linear accelerator CT systems. There is an urgent need for analytical methods to address the complex three-dimensional structure and thermal conductivity analysis requirements of large-scale aeroengine turbine blades. Summary of the Invention

[0005] To overcome these shortcomings, the inventors of the present invention, through long-term exploration, numerous experiments, and continuous innovation, have developed a blade thermal conductivity analysis method based on an electron linear accelerator CT system. This thermal conductivity analysis can be performed directly on the blade's 3D voxel / CT model, eliminating the need to convert the 3D data into point clouds or STL data, thereby avoiding increased detection uncertainty and loss of effective information. Two parallel 2D slices of the blade are designated as the inlet and outlet locations for the thermal conductivity analysis, generating a region for thermal conductivity analysis. The thermal conductivity parameters of the blade material and the relative temperature difference between the inlet and outlet locations are set, and a thermal conductivity analysis algorithm is used to analyze heat conduction within the blade's transfer region. The blade's thermal conductivity analysis is automatically performed by setting a convergence error and a maximum number of iterations. A convergence plot is generated to display the change in convergence error and the current estimate of effective thermal conductivity as the number of iterations increases. In a successful analysis run, the convergence error should converge to zero, and the material property estimates should stabilize at constant values.

[0006] To achieve the above objectives, the present invention employs a technical solution: providing a blade heat conduction analysis method based on an electron linear accelerator CT system. The method comprises the following steps: S1, preheating and conditioning the electron linear accelerator CT system, and then performing bright field / dark field calibration on the CT imaging system; S2, fix the blade to be measured on the rotating console, and obtain the DR scanning data set of the blade by cone beam scanning according to the scanning parameters; S3, reconstructing the DR scan data set of the workpiece into a two-dimensional CT tomographic data set of the blade and a three-dimensional voxel model of the blade using an image reconstruction system according to the image reconstruction parameters; S4, specify any two parallel 2D tomograms of the blade as the inlet and outlet positions of its thermal conductivity analysis to generate the area range of thermal conductivity analysis; S5, setting the thermal conductivity parameters of the blade material and the relative temperature difference between the inlet and outlet positions, setting the convergence error and the maximum number of iterations, automatically performing thermal conductivity analysis of the blade, and forming a convergence diagram; S6, shows the thermal conductivity analysis results.

[0007] According to the present invention, a blade heat conduction analysis method based on an electron linear accelerator CT system includes a further preferred technical solution: a small-focus accelerator tube is used as the X-ray source, with the focus of the accelerator tube reduced to 0.7 mm, thereby improving the image clarity of the blade in the electron linear accelerator CT system. The small-focus accelerator tube utilizes a sapphire energy transmission window and a flat target structure, with a standing wave ratio of less than 1.05.

[0008] According to the blade heat conduction analysis method based on the electron linear accelerator CT system of the present invention, a further preferred technical solution is: in step S5, a heat conduction analysis algorithm is used to analyze the conduction of heat in the blade transfer area.

[0009] According to the blade heat conduction analysis method based on the electron linear accelerator CT system of the present invention, a further preferred technical solution is: in step S5, the convergence error is set to 1×10 -6 ; The maximum number of iterations is 25000.

[0010] According to the blade heat conduction analysis method based on the electron linear accelerator CT system described in the present invention, a further preferred technical solution is: the convergence diagram displays the change of the convergence error and the current estimate of the effective thermal conductivity with the increase of the number of iterations.

[0011] According to the blade heat conduction analysis method based on the electron linear accelerator CT system described in the present invention, a further preferred technical solution is: during the analysis operation, the convergence error converges to zero, and the material property estimation is stabilized at a constant value.

[0012] According to the blade thermal conduction analysis method based on the electron linear accelerator CT system described in the present invention, a further preferred technical solution is: in step S6, the thermal conductivity analysis results are displayed using two color codes relative to temperature and heat flux, and the heat transfer through the blade between the inlet and outlet is displayed in a color-coded manner.

[0013] Compared with the prior art, the technical solution of the present invention has the following advantages / benefits: 1. Heat conduction analysis can be performed directly on the 3D voxel / CT model of the blade without converting the 3D data into point cloud or STL data, thus avoiding increased detection uncertainty and loss of effective information.

[0014] 2. Specify any two parallel 2D slices of the blade as the inlet and outlet locations for the thermal conductivity analysis to generate the area range for the thermal conductivity analysis. Set the thermal conductivity parameters of the blade material and the relative temperature difference between the inlet and outlet locations, and use the thermal conductivity analysis algorithm to analyze the conduction of heat in the blade transfer area. Set the convergence error and the maximum number of iterations to automatically perform the thermal conductivity analysis of the blade, and generate a convergence diagram showing the change of the convergence error and the current estimate of the effective thermal conductivity with the increase of the number of iterations. In a successful analysis run, the convergence error should converge to zero, and the material property estimate should stabilize at a constant value. The complex 3D structure of large-scale aircraft engine turbine blades is split and simplified, and the analysis method is solved while obtaining more accurate and efficient analysis results.

[0015] 3. The thermal conductivity analysis results are displayed in two color codes: relative temperature and heat flux. The heat transfer through the blades between the inlet and outlet is displayed in a color-coded manner, which is clearer and more intuitive.

[0016] 4. A small-focus accelerator tube is used as the X-ray source, reducing the focus of the accelerator tube to 0.7mm, improving the image clarity of the blade's electron linear accelerator CT system. The small-focus accelerator tube uses a sapphire energy transmission window and a flat target structure, with a standing wave ratio of less than 1.05. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 The present invention is a flow chart of a blade heat conduction analysis method based on an electron linear accelerator CT system.

[0019] Figure 2 The present invention is a schematic diagram of a small-focus accelerating tube structure based on a blade heat conduction analysis method of an electron linear accelerator CT system.

[0020] Figure 3 It is a schematic diagram of a three-dimensional blade model of a blade heat conduction analysis method based on an electron linear accelerator CT system of the present invention.

[0021] Figure 4 This is a schematic diagram of the regional range of thermal conductivity analysis of a blade heat conduction analysis method based on an electron linear accelerator CT system of the present invention, wherein yellow represents the inlet and red represents the outlet.

[0022] Figure 5 It is a convergence diagram of thermal conductivity analysis of a blade heat conduction analysis method based on an electron linear accelerator CT system of the present invention.

[0023] Figure 6 The present invention discloses a relative temperature analysis result of blade thermal conductivity based on a blade thermal conduction analysis method of an electron linear accelerator CT system.

[0024] Figure 7 The present invention discloses a heat flux analysis result of blade thermal conductivity based on a blade heat conduction analysis method of an electron linear accelerator CT system. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0026] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it may not be further defined or explained in subsequent drawings.

[0027] Example 1: like Figure 2 As shown, the present invention uses a small-focus accelerating tube as an X-ray source, reducing the accelerating tube focus to 0.7mm, improving the imaging clarity of the electron linear accelerator CT system of the blade. The small-focus accelerating tube adopts a sapphire energy transmission window and a flat target structure, and the standing wave ratio is less than 1.05 (other accelerating tubes that can achieve this parameter can also be used). Figure 1 As shown, the specific steps include: S1, after the electron linear accelerator CT system is preheated and aged, the CT imaging system is calibrated for bright / dark fields; S2, fix the blade to be measured on the rotating console, and obtain the DR scanning data set of the blade by cone beam scanning according to the scanning parameters; S3, based on the image reconstruction parameters, the image reconstruction system is used to reconstruct the DR scan data set of the workpiece into a two-dimensional CT tomographic data set of the blade and a three-dimensional voxel model of the blade. The results are as follows Figure 3 As shown; S4, specify any two parallel 2D tomograms of the blade as the inlet and outlet positions of its thermal conductivity analysis, and generate the area range of the thermal conductivity analysis, such as Figure 3 As shown; S5, set the thermal conductivity parameter of the blade material (1×10 -6 W·m -1 ·K -1 ) and the relative temperature difference between the inlet and outlet locations (1000K), set the convergence error and the maximum number of iterations, use the heat conduction analysis algorithm to analyze the heat transfer in the blade transfer area, and automatically perform the thermal conductivity analysis of the blade. A convergence plot is generated to show how the convergence error and the current estimate of the effective thermal conductivity change as the number of iterations increases. In a successful analysis run, the convergence error should converge to zero, and the material property estimates should stabilize at a constant value. The convergence plot is shown as follows: Figure 4 As shown; S6, such as Figure 5 and Figure 6 As shown, the thermal conductivity analysis results are displayed in two color-coded ways: relative temperature and heat flux. The color-coded display shows the heat transfer through the blade between the inlet and outlet.

[0028] 1. In step S5, the convergence error is set to 1×10 -6 ; The maximum number of iterations is 25000.

[0029] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0030] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0031] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. Persons skilled in the art will appreciate that improvements and modifications may be made without departing from the spirit and scope of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A blade heat conduction analysis method based on an electron linear accelerator CT system, characterized in that: The steps include: S1, after preheating and aging the electron linear accelerator CT system, performing bright / dark field calibration on the CT imaging system; S2, fix the blade to be measured on the rotating console, and obtain the DR scanning data set of the blade by cone beam scanning according to the scanning parameters; S3, reconstructing the DR scan data set of the workpiece into a two-dimensional CT tomographic data set of the blade and a three-dimensional voxel model of the blade using an image reconstruction system according to the image reconstruction parameters; S4, specify any two parallel 2D tomograms of the blade as the inlet and outlet positions of its thermal conductivity analysis to generate the area range of thermal conductivity analysis; S5, setting the thermal conductivity parameters of the blade material and the relative temperature difference between the inlet and outlet positions, setting the convergence error and the maximum number of iterations, automatically performing thermal conductivity analysis of the blade, and forming a convergence diagram; S6, shows the thermal conductivity analysis results.

2. The blade heat conduction analysis method based on an electron linear accelerator CT system according to claim 1, characterized in that: A small focus accelerating tube is used as the X-ray source, and the focus of the accelerating tube is reduced to 0.7mm, thereby improving the imaging clarity of the electron linear accelerator CT system of the blade.

3. The blade heat conduction analysis method based on an electron linear accelerator CT system according to claim 1 is characterized in that: In step S5, a heat conduction analysis algorithm is used to analyze the heat conduction in the blade transfer area.

4. Blade heat conduction analysis method of the accelerator CT system, characterized in that: In step S5, the convergence error is set to 1×10 -6 ; The maximum number of iterations is 25000.

5. The blade heat conduction analysis method based on an electron linear accelerator CT system according to claim 1, characterized in that: The convergence plot shows how the convergence error and the current estimate of the effective thermal conductivity change as the number of iterations increases.

6. The blade heat conduction analysis method based on an electron linear accelerator CT system according to claim 5, characterized in that: During the analysis run, the convergence error converges to zero and the material property estimates stabilize at constant values.

7. The blade heat conduction analysis method based on an electron linear accelerator CT system according to claim 1, characterized in that: In step S6, the thermal conductivity analysis results are displayed using two color codes relative to the temperature and the heat flux, and the heat transfer through the blade between the inlet and the outlet is displayed in a color-coded manner.

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