Film hole configuration method based on point cloud and three-dimensional intrinsic orthogonal decomposition

Abstract

The application discloses a film hole configuration method based on point cloud and three-dimensional intrinsic orthogonal decomposition, and belongs to the field of gas turbine turbine cooling technology. The method solves the problems of low freedom degree of existing film hole parameterization design, difficulty in generating complex hole type and large high-dimensional optimization calculation amount. The main points are as follows: a plurality of benchmark film hole three-dimensional models are aligned and discretized into point cloud vectors with a unified numbering rule; three-dimensional intrinsic orthogonal decomposition is performed on the vectors to obtain an average hole type vector and a geometric principal mode vector sorted according to energy contribution; the first several principal modes are selected, and the amplitudes thereof are taken as shape design parameters; and the three-dimensional geometry of a new film hole is reconstructed through linear superposition of the average hole type and the principal mode vectors according to corresponding parameters. The method can generate a film hole with a complex outlet profile by using low-dimensional parameters, and is used for film cooling design of a turbine blade surface or an end wall.

Description

Technical Field

[0001] This invention belongs to the field of gas turbine cooling technology, and particularly relates to a method for gas film pore configuration based on point cloud and three-dimensional intrinsic orthogonal decomposition. Background Technology

[0002] To improve the thermal efficiency of gas turbines and aero engines, turbine inlet temperatures have been continuously rising, far exceeding the allowable operating temperatures of metallic materials. Therefore, technologies such as internal cooling and external film cooling (FSV) are essential to protect hot-end components like turbine blades and endwalls. Film cooling, by forming a thin film of cool gas between the high-temperature mains and the solid wall, effectively reduces the wall's thermal load and has become one of the most widely used external cooling methods. In existing FSV design practices, regular geometric shapes such as cylindrical holes, simple expansion holes, or fan-shaped holes are commonly used, and their arrangement is designed by adjusting a few intuitive geometric parameters such as hole diameter, aspect ratio, inclination angle, and expansion angle. This method is widely used in the conventional design of FSVs due to its intuitive parameters and ease of fabrication.

[0003] However, this method of directly parameterizing simple geometries has significant limitations. Because the number of adjustable geometric parameters is inherently limited, the resulting family of orifices is also relatively finite, making it difficult to design novel film vents with complex outlet profiles, asymmetric structures, or multi-directional expansion characteristics. This severely restricts the design space and may not meet the specific requirements of different regions of turbine components for cooling airflow coverage shapes. When attempting to introduce more geometric degrees of freedom into numerical optimization to explore better performance, the number of parameters increases rapidly, leading to a sharp rise in the dimensionality of the optimization problem, significantly increasing the computational load, and even causing the "curse of dimensionality," which is often unacceptable in engineering practice.

[0004] While the rapid development of additive manufacturing technology has broken through the limitations of traditional subtractive processing, making it possible to manufacture more complex and precise hole profiles and providing unprecedented freedom for film cooling hole design, the efficient and accurate description and generation of these geometries that meet complex cooling requirements has itself become a new challenge. In other words, there is a disconnect between advanced manufacturing capabilities and efficient design methods. In the past, the lack of effective technical means to extract common features from a large number of reference hole profiles and construct a descriptive system that can cover a broad design space while being controllable with a very small number of parameters resulted in a cumbersome design process, making it difficult to fully utilize the potential of additive manufacturing. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a method for air film pore configuration based on point cloud and three-dimensional intrinsic orthogonal decomposition, thereby resolving the issues present in the prior art.

[0006] In a first aspect, to achieve the above objectives, the present invention provides a method for air film pore configuration based on point cloud and three-dimensional intrinsic orthogonal decomposition, comprising the following steps: Establish a set of three-dimensional geometries containing multiple reference air film holes, and align the reference air film holes in a unified geometric coordinate system; The three-dimensional inner surface of each reference air film pore is discretized into a set of scattered points with a fixed numbering order, forming a three-dimensional geometric vector characterizing each pore type. Perform three-dimensional intrinsic orthogonal decomposition on the three-dimensional geometric vectors of all reference air film pores to obtain an average pore shape vector and a set of geometric principal mode vectors sorted by energy contribution; A low-dimensional parameter space is constructed based on the geometric principal mode vector and its magnitude parameters; The three-dimensional geometry of the target air film pore is reconstructed by linearly superimposing the average aperture vector with several selected geometric principal mode vectors according to their corresponding amplitude parameters.

[0007] Optionally, the process of discretizing the three-dimensional inner surface of each reference air film pore into a scatter set includes: Multiple cross sections perpendicular to the air film pores are cut along the axial direction. On each cross section, discrete points are collected at equal angular intervals along the circumference of the hole profile, with the intersection of the axis and the cross section as the pole. Assign the same number to the corresponding discrete points of all reference air film holes.

[0008] Optionally, the process of cutting multiple cross sections along the axial direction of the air film hole is to cut them at fixed vertical distances at equal intervals along the hole axis in the unified geometric coordinate system. The total number of scatter points in the scatter set ranges from 1,000 to 10,000.

[0009] Optionally, the process of performing three-dimensional intrinsic orthogonal decomposition may employ the snapshot intrinsic orthogonal decomposition method; The process of constructing a low-dimensional parameter space based on geometric principal mode vectors involves selecting the top few geometric principal mode vectors with a cumulative energy contribution rate exceeding 70%, and defining the magnitude of each vector as a shape design parameter.

[0010] Optionally, in the process of reconstructing the three-dimensional geometry of the target air film pore, the range of values ​​for the shape design parameters is limited to a range that ensures the three-dimensional inner surface of the reconstructed air film pore is free of self-intersections and continuously smooth.

[0011] Optionally, the three-dimensional eigenorthogonal decomposition process also includes: Analyze the impact of variations in a single shape design parameter on the reconstructed geometric features of the air film pores; Based on the aforementioned influence, a corresponding physical geometric meaning is assigned to the geometric principal modal vector associated with each of the shape design parameters.

[0012] Optionally, after reconstructing the three-dimensional geometry of the target air film pore, the method further includes converting the reconstructed three-dimensional geometry into a three-dimensional computer-aided design model file or a three-dimensional printing file.

[0013] Secondly, the present invention also provides a computer terminal device, comprising: One or more processors; A memory, coupled to the processor, for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the steps of the air film pore configuration method based on point cloud and three-dimensional intrinsic orthogonal decomposition in the first aspect above.

[0014] Thirdly, the present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, it implements the steps of the air film pore configuration method based on point cloud and three-dimensional intrinsic orthogonal decomposition in the first aspect described above.

[0015] Fourthly, the present invention also provides a computer program product, including a computer program, characterized in that, when the computer program is executed by a processor, it implements the steps of the air film pore configuration method based on point cloud and three-dimensional intrinsic orthogonal decomposition in the first aspect described above.

[0016] Compared with the prior art, the present invention has the following advantages and technical effects: The film cooling orifice (FSA) configuration method based on point cloud and 3D intrinsic orthogonal decomposition provided by this invention can significantly reduce the dimensionality of the FSA geometry description, representing complex 3D orifice shapes with a very small number of shape design parameters. This greatly reduces the number of variables in subsequent optimization design and improves design efficiency. By linearly combining the geometric principal modes extracted from a diverse set of baseline orifice shapes, this invention can generate new FSAs with rich outlet expansion and contraction characteristics while ensuring continuous smoothness and manufacturability of the orifice surface. This effectively expands the design space limited by traditional parametric methods. Furthermore, the low-dimensional parametric model constructed by this invention is easy to integrate with computational fluid dynamics simulations or engineering experience, supporting rapid evaluation and screening of the FSA efficiency and aerodynamic losses of various orifice schemes. This provides a flexible and efficient tool for the FSA design of turbine blades and endwalls. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the reference air film pore set and its selected cross-section in a unified coordinate system, according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the discrete points and vectorization method of a certain reference hole type surface according to an embodiment of the present invention; Figure 3 This is a schematic flowchart of the air film pore configuration method according to an embodiment of the present invention; Figure 4 This is a graph showing the energy contribution of different POD modes and the cumulative energy contribution of the first 10 modes in an embodiment of the present invention. Figure 5 This is a three-dimensional schematic diagram of the average hole shape generated based on 18 reference hole shapes according to an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the change in orifice outlet shape before and after changing different POD shape parameters according to an embodiment of the present invention. Detailed Implementation

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0020] This embodiment provides a method for air film pore configuration based on point cloud and three-dimensional intrinsic orthogonal decomposition, including: Establish a set of three-dimensional geometries containing multiple reference air film holes, and align the reference air film holes in a unified geometric coordinate system; The three-dimensional inner surface of each reference air film pore is discretized into a set of scattered points with a fixed numbering order, forming a three-dimensional geometric vector characterizing each pore type. Perform three-dimensional intrinsic orthogonal decomposition on the three-dimensional geometric vectors of all reference air film pores to obtain an average pore shape vector and a set of geometric principal mode vectors sorted by energy contribution; A low-dimensional parameter space is constructed based on the geometric principal mode vector and its magnitude parameters; The three-dimensional geometry of the target air film pore is reconstructed by linearly superimposing the average aperture vector with several selected geometric principal mode vectors according to their corresponding amplitude parameters.

[0021] Furthermore, the process of discretizing the three-dimensional inner surface of each reference air film pore into a scatter set includes: Multiple cross sections perpendicular to the air film pores are cut along the axial direction. On each cross section, discrete points are collected at equal angular intervals along the circumference of the hole profile, with the intersection of the axis and the cross section as the pole. Assign the same number to the corresponding discrete points of all reference air film holes.

[0022] Furthermore, the process of cutting multiple cross sections along the axial direction of the air film hole is to cut them at fixed vertical distances at equal intervals under the unified geometric coordinate system. The total number of scatter points in the scatter set ranges from 1,000 to 10,000.

[0023] Furthermore, the process of performing three-dimensional intrinsic orthogonal decomposition adopts the snapshot intrinsic orthogonal decomposition method; The process of constructing a low-dimensional parameter space based on geometric principal mode vectors involves selecting the top few geometric principal mode vectors with a cumulative energy contribution rate exceeding 70%, and defining the magnitude of each vector as a shape design parameter.

[0024] Furthermore, in the process of reconstructing the three-dimensional geometry of the target air film pore, the range of values ​​for the shape design parameters is limited to a numerical range that ensures the three-dimensional inner surface of the reconstructed air film pore is free of self-intersections and continuously smooth.

[0025] Furthermore, the process of three-dimensional eigenorthogonal decomposition also includes: Analyze the impact of variations in a single shape design parameter on the reconstructed geometric features of the air film pores; Based on the aforementioned influence, a corresponding physical geometric meaning is assigned to the geometric principal modal vector associated with each of the shape design parameters.

[0026] Furthermore, after reconstructing the three-dimensional geometry of the target air film pore, the process also includes converting the reconstructed three-dimensional geometry into a three-dimensional computer-aided design model file or a three-dimensional printing file.

[0027] Specifically, such as Figure 3 The implementation process of this embodiment shown includes: Step 1: Establishment of the reference aperture set. Based on the cooling requirements of the target turbine component, select several representative three-dimensional geometries of film cooling holes as reference aperture types. These reference aperture types may include cylindrical apertures, forward-expanding apertures, swept-back fan-shaped apertures, and other existing or empirically designed aperture types. Preferably, the number of reference aperture types is no less than 10. For example, 18 reference aperture types with different inlet and outlet shapes and expansion forms can be selected. The aperture axis direction, inlet area, and aperture length of each reference aperture type are unified to the same coordinate system and the same characteristic dimension. Step 2: Hole Surface Scattering and Vectorization. The 3D hole surface of each reference hole type is divided into several sections perpendicular to the hole axis along the hole axis. Contour points are sampled at equal intervals along the circumferential angle on each section, ensuring that the k-th point on the same section corresponds to the same geometric position for all reference hole types. All scattered points of each hole type are concatenated into a vector in a fixed order to represent the 3D geometry of the hole type. The total number of scattered points is controlled between 1000 and 10000; for example, approximately 4000 points can adequately describe the hole type. Step 3: 3D POD Decomposition. Using the geometric vectors of each reference aperture as samples, the snapshot POD method is used to construct the covariance matrix and solve for the eigenvalues ​​and eigenvectors, obtaining the average aperture vector and a set of mutually orthogonal geometric principal mode vectors. The eigenvalues ​​corresponding to each principal mode give their contribution rate, which reflects the amount of geometric information contained in that mode; Step 4: Principal Mode Selection and Parameterization. Sort the geometric principal modes according to their contribution rate from largest to smallest, and select the top n principal modes whose cumulative contribution rate reaches a predetermined threshold. For example, selecting the top 5 modes may result in a cumulative contribution rate of over 70%. Define the amplitudes of these n principal modes as POD shape parameters, constructing a low-dimensional geometric parameter space. For ease of use, the POD shape parameters can be linearly scaled and normalized to the [-1, 1] interval. Step 5: New Aperture Reconstruction. Given a set of POD shape parameters, the average aperture vector is linearly superimposed with each geometric principal mode according to their corresponding amplitudes to obtain the geometric vector of the target air film aperture. This vector is then restored to spatial scatter points to generate a 3D aperture surface model. During the generation process, the presence of self-intersections on the aperture surface is checked by distance determination. If self-intersections exist, the range of POD shape parameters is automatically adjusted or limited to ensure that the obtained aperture surface is continuous and smooth. Step 6: Obtaining the physical meaning of the geometric modes. To facilitate use by engineers, all parameters except for a certain POD shape parameter are fixed at zero or a reference value. The amplitude of the parameter is changed and the orifice shape is reconstructed. The changes in geometric features such as orifice outlet flow direction expansion, spanwise width, and upstream / downstream edge shape are observed. This gives each geometric master mode an intuitive physical description. For example, one mode mainly controls the bulging or contraction of the downstream wall of the orifice outlet, while another mode mainly controls the expansion width of the orifice outlet along the mainstream direction. Step 7: Engineering Application. The POD shape parameter space obtained from the above steps can be used in conjunction with CFD calculations or other design criteria. By changing the POD shape parameters, various film cooling hole schemes can be generated, and their film cooling efficiency and aerodynamic losses can be evaluated. The hole type that meets the requirements of different operating conditions can be selected for turbine blade or endwall cooling.

[0028] In this embodiment, a computer terminal device is provided, including: One or more processors; A memory, coupled to the processor, for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the steps of the above-described method for air film pore configuration based on point cloud and three-dimensional intrinsic orthogonal decomposition.

[0029] In this embodiment, a computer-readable storage medium is also provided, on which a computer program is stored. When the computer program is executed by a processor, it implements the steps of the above-described method for air film pore configuration based on point cloud and three-dimensional intrinsic orthogonal decomposition.

[0030] In this embodiment, a computer program product is also provided, including a computer program, characterized in that, when the computer program is executed by a processor, it implements the steps of the above-described method for air film pore configuration based on point cloud and three-dimensional intrinsic orthogonal decomposition.

[0031] Example 1: POD film pore configuration method based on 18 reference pore types like Figure 1 As shown in (a), this embodiment uses Solidworks software to model 18 selected three-dimensional reference hole types, including cylindrical holes, fan-shaped holes with expansion on both sides, and forward contraction-backward expansion combined holes, and unifies related geometric parameters such as hole axis inclination angle, inlet area and hole length.

[0032] like Figure 1 As shown in (b), for each reference hole type, several cross sections are first divided at equal intervals along the hole axis. Then, on each cross section, contour points are sampled at equal angles along the circumference using polar coordinates, resulting in approximately 3600 scattered points. Figure 2 As shown, the three-dimensional coordinates of each scattered point are arranged into a geometric vector according to their numbering order to represent the hole type. For all reference hole types, the same number of cross sections and sampling rules are used to ensure a one-to-one correspondence between the corresponding positions of different hole types in the vector space.

[0033] Using the geometric vectors of all reference aperture types as samples, the snapshot POD method is used to solve for the eigenvalues ​​and eigenvectors of the covariance matrix. The obtained eigenvectors are sorted from largest to smallest eigenvalue, which represent the geometric principal modes. The ratio of the eigenvalue to the sum is used as the contribution rate of the corresponding mode, such as... Figure 4As shown. Calculation results show that the cumulative contribution rate of the first 5 principal modes exceeds 70%. Therefore, in this embodiment, these 5 principal modes are selected for the configuration, and the influence of other higher-order modes on the orifice shape is relatively small and is ignored. The amplitude of each principal mode is defined as the shape parameter corresponding to POD1 to POD5. By scanning individual parameters, their geometric meaning can be obtained: for example, when POD1 changes from a negative value to a positive value, the downstream sidewall of the orifice outlet gradually bulges out from contraction; POD2 mainly changes the expansion width of the outlet along the mainstream direction; POD3 mainly adjusts the shape of the downstream edge of the outlet; POD4 changes the forward expansion angle and the extension degree of the outlet along the flow direction more; POD5 mainly affects the upstream edge of the outlet.

[0034] In engineering design, designers set a set of values ​​from POD1 to POD5 as needed, and use the POD linear combination formula to calculate the average aperture type (e.g., Figure 5 The geometric vectors of the corresponding hole types are superimposed with the principal modes to reconstruct the three-dimensional hole surface. For example... Figure 6 As shown, the generated hole shape can be directly output as an STL or CAD surface file, input into automatic mesh generation software to generate a fine mesh near the hole, and then CFD calculations are performed under different working conditions to evaluate its film cooling effect.

[0035] It should be noted that the number of reference hole types, the number of scattered points, and the number of principal modes selected in this embodiment are not unique. As long as the cumulative contribution rate of the principal modes of POD reaches a predetermined level, a new family of hole types that meets engineering accuracy can be obtained. If it is necessary to describe certain local geometric features more precisely, the number of scattered points or more POD modes can be selected appropriately. The method of this invention does not limit this.

[0036] Example 2: POD film pore configuration for end-wall cooling In end-wall cooling design, the method of this invention can be combined with end-wall flow and heat transfer characteristics. First, a baseline orifice set is established and POD decomposition is completed according to the method in Example 1. Then, based on the pressure gradient and heat transfer coefficient of different regions of the endwall, suitable POD parameter combinations for suppressing jet lift-off or enhancing lateral diffusion are selected to generate orifices for different regions. For example, a POD combination with strong lateral expansion characteristics can be used in the high heat transfer region near the pressure surface, while a POD combination with enhanced forward coverage is used in the leading edge region. Through a unified POD parameter space, various orifice types suitable for different regions of the endwall can be quickly generated, significantly reducing the workload of repeated modeling and parameter tuning.

[0037] The film cooling orifice (FSA) configuration method based on point cloud and 3D intrinsic orthogonal decomposition provided by this invention can significantly reduce the dimensionality of the FSA geometry description, representing complex 3D orifice shapes with a very small number of shape design parameters. This greatly reduces the number of variables in subsequent optimization design and improves design efficiency. By linearly combining the geometric principal modes extracted from a diverse set of baseline orifice shapes, this invention can generate new FSAs with rich outlet expansion and contraction characteristics while ensuring continuous smoothness and manufacturability of the orifice surface. This effectively expands the design space limited by traditional parametric methods. Furthermore, the low-dimensional parametric model constructed by this invention is easy to integrate with computational fluid dynamics simulations or engineering experience, supporting rapid evaluation and screening of the FSA efficiency and aerodynamic losses of various orifice schemes. This provides a flexible and efficient tool for the FSA design of turbine blades and endwalls.

[0038] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for air film pore configuration based on point cloud and three-dimensional intrinsic orthogonal decomposition, characterized in that, Includes the following steps: Establish a set of three-dimensional geometries containing multiple reference air film holes, and align the reference air film holes in a unified geometric coordinate system; The three-dimensional inner surface of each reference air film pore is discretized into a set of scattered points with a fixed numbering order, forming a three-dimensional geometric vector characterizing each pore type. Perform three-dimensional intrinsic orthogonal decomposition on the three-dimensional geometric vectors of all reference air film pores to obtain an average pore shape vector and a set of geometric principal mode vectors sorted by energy contribution; A low-dimensional parameter space is constructed based on the geometric principal mode vector and its magnitude parameters; The three-dimensional geometry of the target air film pore is reconstructed by linearly superimposing the average aperture vector with several selected geometric principal mode vectors according to their corresponding amplitude parameters.

2. The method according to claim 1, characterized in that, The process of discretizing the three-dimensional inner surface of each reference air film pore into a scatter set includes: Multiple cross sections perpendicular to the air film pores are cut along the axial direction. On each cross section, discrete points are collected at equal angular intervals along the circumference of the hole profile, with the intersection of the axis and the cross section as the pole. Assign the same number to the corresponding discrete points of all reference air film holes.

3. The method according to claim 2, characterized in that, The process of cutting multiple cross sections along the axial direction of the air film hole is to cut them at fixed vertical distances at equal intervals under the unified geometric coordinate system. The total number of scatter points in the scatter set ranges from 1,000 to 10,000.

4. The method according to claim 1, characterized in that, The process of performing three-dimensional intrinsic orthogonal decomposition adopts the snapshot intrinsic orthogonal decomposition method; The process of constructing a low-dimensional parameter space based on geometric principal mode vectors involves selecting the top few geometric principal mode vectors with a cumulative energy contribution rate exceeding 70%, and defining the magnitude of each vector as a shape design parameter.

5. The method according to claim 4, characterized in that, The process of reconstructing the three-dimensional geometry of the target air film pore involves limiting the range of values ​​for the shape design parameters to a range that ensures the reconstructed air film pore's three-dimensional inner surface is free of self-intersections and continuously smooth.

6. The method according to claim 4, characterized in that, The process of three-dimensional eigenorthogonal decomposition also includes: Analyze the impact of variations in a single shape design parameter on the reconstructed geometric features of the air film pores; Based on the aforementioned influence, a corresponding physical geometric meaning is assigned to the geometric principal modal vector associated with each of the shape design parameters.

7. The method according to claim 1, characterized in that, After reconstructing the three-dimensional geometry of the target air film pore, the process also includes converting the reconstructed three-dimensional geometry into a three-dimensional computer-aided design model file or a three-dimensional printing file.

8. A computer terminal device, characterized in that, include: One or more processors; A memory, coupled to the processor, for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors perform the steps of the method as described in any one of claims 1-7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1-7.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1-7.

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