A method, device and equipment for identifying the axis of cylindrical components for CFD

Abstract

A method, device and equipment for identifying the axis of a cylindrical component for CFD, which relates to the technical field of feature recognition of CFD simulation models, and solves the technical problem of "how to automatically identify the axis of a cylindrical component". The method comprises: obtaining a cylindrical component mesh; extracting a surface mesh set based on the cylindrical component mesh; triangulating the surface mesh set; identifying feature edges of the triangulated surface mesh set; dividing the identified feature edges into two sets, each feature edge set being used to represent a bottom surface of a cylindrical component; determining the center of the two bottom surfaces of the cylindrical component based on the feature edge set, and then calculating the axis of the cylindrical component; the method extracts the surface mesh and rearranges the feature edges therein to calculate the axis of the cylindrical component, and can realize automatic identification of the axis of the cylindrical component with high identification accuracy, effectively improving the efficiency of simulation calculation, and providing a better user experience, and can be applied to the field of CFD simulation calculation.

Description

Technical Field

[0001] The invention relates to the technical field of CFD simulation model feature recognition. Background Art

[0002] In CFD simulation analysis examples, rotating parts are often involved, such as aircraft engine blades, ship propeller sleeves, automobile and high-speed rail wheels, etc. In some simulation scenarios, the rotation of the parts will have a great impact on the characteristics of the flow field, which is one of the factors that must be considered. In order to simplify the analysis and obtain qualitative results, in most cases these rotating parts are simplified to cylindrical components rotating around the axis. Therefore, a large number of cylindrical components will be encountered in CFD simulation calculations.

[0003] During CFD simulation calculations, it is necessary to obtain the axis position of the cylinder. In some cases, it is necessary to specify the axis position of the cylinder during model preprocessing. The currently commonly used technology is to specify it through human-computer interaction, specifically by inputting the reference point and direction of the axis or by interactively selecting two points through a graphical interface. This axis specification method has the problems of low efficiency and large errors, and the user experience is poor. Especially for axes that are not parallel to any coordinate axis of the coordinate system, the error will be greater if the above axis specification method is used.

[0004] In practical applications, it is very important to accurately calculate the axis position of cylindrical components. For example, in the calculation of the external fluid domain of a car model, the error in the axis position will affect the force balance of the wheel at high speed, making it difficult for the speed to reach a stable state, which in turn reduces the accuracy of the calculation of the external fluid domain data of the car model at high speed.

[0005] Therefore, how to provide a method that can accurately and efficiently automatically identify the axis of a cylindrical component has become a technical problem that needs to be urgently solved in this field. Summary of the invention

[0006] In order to solve the technical problems existing in the prior art, the present invention provides a CFD-oriented cylindrical component axis identification method, device and equipment. The method obtains the axis of the cylindrical component by extracting the surface mesh and rearranging the characteristic edges therein. The method can realize automatic identification of the axis of the cylindrical component with high identification accuracy, effectively improves the efficiency of simulation calculation, and provides a better user experience.

[0007] Based on the same inventive concept, the present invention has three independent technical solutions:

[0008] 1. A method for identifying the axis of a cylindrical component for CFD, the method comprising the following steps:

[0009] S1. Obtain the mesh of the cylindrical component;

[0010] S2. extracting a surface mesh set based on the cylindrical component mesh;

[0011] S3, triangulating the surface mesh set;

[0012] S4, identifying feature edges of the triangulated surface mesh set;

[0013] S5, dividing the identified feature edges into two sets, each feature edge set is used to represent a bottom surface of the cylindrical component;

[0014] S6. Determine the centers of the two bottom surfaces of the cylindrical component based on the characteristic edge set, and then calculate the axis of the cylindrical component.

[0015] Further, step S2 includes:

[0016] The following operation is performed on all mesh units in the cylindrical component mesh: all faces in the mesh unit are traversed to determine whether there are other mesh units containing the same face, if so, the face is not a surface mesh, otherwise the face is a surface mesh.

[0017] Furthermore, if the difference set of the vertex index arrays of two faces is an empty set, the two faces are the same face.

[0018] Further, step S3 includes:

[0019] The following operations are performed on all mesh units in the surface mesh set: determine whether the mesh unit is a triangular mesh; if not, select any vertex of the mesh unit, and connect all vertices that are not adjacent to the vertex to the vertex, respectively, to split the mesh unit into at least two triangular meshes.

[0020] Further, step S4 includes:

[0021] The following operations are performed on all triangular mesh units in the triangulated surface mesh set: all edges in the triangular mesh units are traversed, and the angle between two triangular mesh units where each edge is located is calculated. If the angle is less than a preset angle, the edge is a feature edge, otherwise it is not.

[0022] Furthermore, the angle between two triangular mesh units is calculated by the following steps:

[0023] According to the order of the vertex index of the triangular mesh unit and the right-hand screw rule, two triangular mesh unit normals are obtained respectively;

[0024] Calculating the normal angle between two normal lines of the triangular mesh unit;

[0025] The supplementary angle of the normal angle is calculated as the angle between the two triangular mesh units.

[0026] Further, step S5 includes:

[0027] S51, randomly select a characteristic edge as the current edge;

[0028] S52, obtaining two vertex indexes of the current edge;

[0029] S53, querying two other feature edges containing the vertex index, and connecting them with the current edge to obtain a new current edge, wherein different edges are connected by vertices with the same vertex index;

[0030] S54, repeat steps S52-S53 until the two vertex indexes of the current edge are the same, and a first characteristic edge set is obtained;

[0031] S55. Repeat steps S51-S54 on the remaining feature edges to obtain a second feature edge set.

[0032] Furthermore, the center of the circle is determined by the following method: three vertices are randomly selected from the characteristic edge set to determine a triangle, and the center of the circumscribed circle of the triangle is used as the center of the bottom surface of the cylindrical component.

[0033] 2. A cylindrical component axis identification device for CFD, comprising:

[0034] A mesh acquisition module, used to acquire the mesh of cylindrical components;

[0035] A surface mesh extraction module, used for extracting a surface mesh set based on the cylindrical component mesh;

[0036] A triangulation module, used for triangulating the surface mesh set;

[0037] A feature edge recognition module is used to perform feature edge recognition on a triangulated surface mesh set;

[0038] A feature edge rearrangement module is used to divide the identified feature edges into two sets, each feature edge set is used to represent a bottom surface of the cylindrical component;

[0039] The axis calculation module determines the centers of the two bottom surfaces of the cylindrical component based on the characteristic edge set, and then calculates the axis of the cylindrical component.

[0040] 3. An electronic device, comprising a processor and a storage device, wherein the storage device stores a plurality of instructions, and the processor is used to read the plurality of instructions in the storage device and execute the above method.

[0041] The cylindrical component axis identification method, device and equipment for CFD provided by the present invention have at least the following beneficial effects:

[0042] This method extracts the surface mesh and rearranges the characteristic edges therein to calculate the axis of the cylindrical component, which can realize automatic recognition of the axis of the cylindrical component. There is no need to manually input the reference point and direction of the axis through human-computer interaction in the model preprocessing stage, which effectively improves the efficiency of the simulation calculation. At the same time, the automatic recognition method can obtain a higher recognition accuracy, and the recognition measurement error is less than 0.2%, especially for the axis that is not parallel to any coordinate axis of the coordinate system. The accuracy improvement is more obvious than that obtained by human-computer interaction. This method improves the efficiency while also improving the accuracy of axis recognition, and provides a better user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A flow chart of an embodiment of a method for identifying the axis of a cylindrical component for CFD provided by the present invention;

[0044] Figure 2 A schematic structural diagram of an embodiment of a cylindrical component mesh for identification by a cylindrical component axis identification method for CFD provided by the present invention;

[0045] Figure 3 A schematic diagram of an embodiment of a grid unit in a cylindrical component used for identifying the axis line of a cylindrical component provided by the CFD-oriented cylindrical component method of the present invention;

[0046] Figure 4 A schematic diagram of an embodiment of a mesh triangulation process in a cylindrical component axis identification method for CFD provided by the present invention;

[0047] Figure 5 A schematic diagram of an embodiment of a process for calculating the angle of a grid unit in a cylindrical component axis identification method for CFD provided by the present invention;

[0048] Figure 6 A schematic diagram of an embodiment of a feature edge reorganization and sorting process in a cylindrical component axis recognition method for CFD provided by the present invention;

[0049] Figure 7 A schematic diagram of an embodiment of a bottom surface center calculation process in a cylindrical component axis identification method for CFD provided by the present invention. DETAILED DESCRIPTION

[0050] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0051] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0052] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0053] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, the singular forms "a", "an" and "the" are intended to include plural forms unless the context clearly indicates otherwise.

[0054] The following is a clear and complete description of the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0055] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0056] Embodiment 1:

[0057] See also Figure 1 In some embodiments, a method for identifying the axis of a cylindrical component for CFD is provided, the method comprising the following steps:

[0058] S1. Obtain the mesh of the cylindrical component;

[0059] S2. extracting a surface mesh set based on the cylindrical component mesh;

[0060] S3, triangulating the surface mesh set;

[0061] S4, identifying feature edges of the triangulated surface mesh set;

[0062] S5, dividing the identified feature edges into two sets, each feature edge set is used to represent a bottom surface of the cylindrical component;

[0063] S6. Determine the centers of the two bottom surfaces of the cylindrical component based on the characteristic edge set, and then calculate the axis of the cylindrical component.

[0064] Specifically, in step S1, the mesh of the three-dimensional cylindrical component is obtained, and the expression of the mesh is divided into two parts, the first is the three-dimensional coordinate value of the node, and the second is the topological information of the mesh unit. The topological information of the mesh unit includes the type of unit (triangle, quadrilateral, tetrahedron, hexahedron, etc.) and the ordered unit vertex index number. The topology of the face and edge can be determined according to the vertex index order of the mesh unit. The topological expression of the face and edge is consistent with the topological expression of the unit, and is expressed in the form of ordered vertex indexes.

[0065] For example, Figure 2 There are 327 vertices in the cylindrical component shown. The coordinates of these vertices do not overlap in space and are numbered 1-327. Figure 3 , there is a tetrahedron surrounded by nodes with vertex numbers [56,235,68,103]. Then this tetrahedron has four faces, which are represented by vertex numbers as [56,235,68][56,235,103][56,68,103][235,68,103]. This tetrahedron has 6 edges, namely [56,235][56,68][56,103][235,68][235,103][68,103].

[0066] The input mesh unit types include volume unit types and surface unit types. Volume unit types include tetrahedron and hexahedron, and surface unit types include polygons such as triangle, quadrilateral and pentagon.

[0067] In step S2, the surface mesh refers to the surface mesh of the model, which can be described by topological description as a collection of faces belonging to only one mesh unit.

[0068] Therefore, extracting a surface mesh set based on the cylindrical component mesh includes: performing the following operations on all mesh units in the cylindrical component mesh: traversing all faces in the mesh unit to determine whether there are other mesh units containing the same face; if so, the face is not a surface mesh, otherwise the face is a surface mesh.

[0069] The basis for judging whether two faces are the same face is that if the difference set of the vertex index arrays of the two faces is an empty set, the two faces are the same face.

[0070] It should be noted that the set of face meshes extracted from the surface mesh only includes triangles and quadrilaterals.

[0071] Step S3 includes:

[0072] The following operations are performed on all mesh units in the surface mesh set: determine whether the mesh unit is a triangular mesh; if not, select any vertex of the mesh unit, and connect all vertices that are not adjacent to the vertex to the vertex, respectively, to split the mesh unit into at least two triangular meshes.

[0073] In some embodiments, the selected vertices in the grid unit are numbered 1, the 1st vertex of the polygonal mesh is connected to the 3rd to N-1th vertices respectively, and the polygonal grid unit is split into N-2 triangular grids, where N is the number of vertices of the polygonal mesh and N is not less than 4.

[0074] Specifically, the surface mesh types obtained through surface mesh extraction may include polygonal meshes such as triangular meshes, quadrilateral meshes, and pentagonal meshes. Mesh triangulation is to convert all meshes into triangular meshes. For example, refer to Figure 4 , a quadrilateral face can be represented as [25,36,89,120], then after triangulation it will be split into two triangles, namely [25,36,89][25,89,120].

[0075] It should be noted that the characteristic edge is an edge with a relatively large curvature on the outer surface. The curvature of the edge is represented by the supplementary angle of the angle between the normals of the triangles on both sides of the edge. The smaller the supplementary angle, the greater the curvature of the edge.

[0076] In step S4, feature edge recognition is performed on the triangulated surface mesh set, including:

[0077] The following operations are performed on all triangular mesh units in the triangulated surface mesh set: all edges in the triangular mesh units are traversed, and the angle between two triangular mesh units where each edge is located is calculated. If the angle is less than a preset angle, the edge is a feature edge, otherwise it is not.

[0078] As a preferred implementation, the preset angle is 120 degrees. In actual operation, if the supplementary angle is less than 120 degrees, the edge is considered to be a characteristic edge.

[0079] The angle between two triangular mesh units is calculated by the following steps:

[0080] S41, obtaining two normal lines of the triangular mesh units according to the order of the vertex indexes of the triangular mesh units and the right-hand screw rule;

[0081] S42, calculating the normal angle between two normal lines of the triangular mesh units;

[0082] S43, calculating the supplementary angle of the normal angle as the angle between two triangular mesh units.

[0083] refer to Figure 5 In a triangular mesh, each mesh unit is composed of three points. The normals L1 and L2 of the unit can be determined by the order of vertex indices and the right-hand screw rule. After determining the normals of adjacent mesh units, the supplementary angle b of the angle a between the normals of two adjacent mesh units is the angle between the two mesh units.

[0084] It should be noted that in step S4, a set of characteristic edges is obtained by searching for characteristic edges, but the set is an unordered set. The characteristic edges need to be grouped and sorted. The characteristic edge grouping and sorting is to group the interconnected characteristic edges into one group. Figure 2 A total of 38 feature edges are extracted from the cylindrical component model shown. These 38 edges can be divided into two groups: upper and lower bottom surfaces.

[0085] Specifically, in step S5, the identified feature edges are divided into two sets, each of which is used to represent a bottom surface of a cylindrical component, including:

[0086] S51, randomly select a characteristic edge as the current edge;

[0087] S52, obtaining two vertex index numbers of the current edge;

[0088] S53, querying two other characteristic edges containing the vertex index numbers, and connecting them with the current edge to obtain a new current edge, wherein different edges are connected through vertices with the same index number;

[0089] S54, repeat steps S52-S53 until the two vertex index numbers of the current edge are the same, and a first characteristic edge set is obtained;

[0090] S55. Repeat steps S51-S54 on the remaining feature edges to obtain a second feature edge set.

[0091] In a specific application scenario, Figure 2 For example, the grouping and sorting process of the characteristic edges of the cylindrical component shown in Figure 6First, by taking any feature edge in the set, two vertex index IDs can be obtained. Through the two vertex index IDs, two other feature edges containing these two vertices can be queried in the feature edge set respectively; then, a new edge and two new vertex IDs can be formed through the original feature edge and the two queried feature edges; the above process is repeated until the two vertex IDs are repeated, and the edge obtained is the edge of a bottom surface of the cylindrical component, where the set composed of all the feature edges in the cylindrical edge is called the first feature edge set.

[0092] Correspondingly, the other side of the cylinder can be obtained by the remaining feature edges in the feature edge set, and the above method is repeated to obtain another cylinder side, which is called the second feature edge set.

[0093] In step S6, the circle center calculation includes the following steps: randomly selecting three vertices in the characteristic edge set to determine a triangle, and taking the center of the circumscribed circle of the triangle as the center of the bottom surface of the cylindrical component.

[0094] By reorganizing and sorting the characteristic edges, we get the first characteristic edge set and the second characteristic edge set. We can select three points at random from the edges of the first characteristic edge set and the second characteristic edge set, and use the three points to determine a circle and its center. Figure 7 Through the three points P1, P2, and P3, we can determine a triangle. Through the sides of the triangle, we can determine the two perpendicular bisectors S1 and S2. The intersection point O of S1 and S2 is the center of the circle O.

[0095] In step S6, after the centers of the two bottom surfaces of the cylindrical component are determined, the axis of the cylindrical component can be calculated through the two points, and the line connecting the two centers is the axis.

[0096] Embodiment 2:

[0097] In some embodiments, a cylindrical component axis identification device for CFD is provided, comprising:

[0098] A mesh acquisition module, used to acquire the mesh of cylindrical components;

[0099] A surface mesh extraction module, used for extracting a surface mesh set based on the cylindrical component mesh;

[0100] A triangulation module, used for triangulating the surface mesh set;

[0101] A feature edge recognition module is used to perform feature edge recognition on a triangulated surface mesh set;

[0102] A feature edge rearrangement module is used to divide the identified feature edges into two feature edge sets, and the feature edges contained in each feature edge set are connected end to end to form a closed loop;

[0103] The axis calculation module is used to determine the two centers of the cylindrical component based on the two characteristic edge sets, and then calculate the axis of the cylindrical component.

[0104] As a preferred implementation, the surface mesh extraction module is further used for:

[0105] The following operation is performed on all mesh units in the cylindrical component mesh: all faces in the mesh unit are traversed to determine whether there are other mesh units containing the same face, if so, the face is not a surface mesh, otherwise the face is a surface mesh.

[0106] Among them, if the difference set of the vertex index arrays of two faces is an empty set, the two faces are the same face.

[0107] As a preferred implementation, the triangulation module is further used for:

[0108] The following operations are performed on all mesh units in the surface mesh set: determine whether the mesh unit is a triangular mesh; if not, select any vertex of the mesh unit, and connect all vertices that are not adjacent to the vertex to the vertex, respectively, to split the mesh unit into at least two triangular meshes.

[0109] As a preferred implementation, the feature edge recognition module is further used for:

[0110] The following operations are performed on all triangular mesh units in the triangulated surface mesh set: all edges in the triangular mesh units are traversed, and the angle between two triangular mesh units where each edge is located is calculated. If the angle is less than a preset angle, the edge is a feature edge, otherwise it is not.

[0111] The angle between two triangular mesh units is calculated by the following steps:

[0112] According to the order of the vertex index of the triangular mesh unit and the right-hand screw rule, two triangular mesh unit normals are obtained respectively;

[0113] Calculating the normal angle between two normal lines of the triangular mesh unit;

[0114] The supplementary angle of the normal angle is calculated as the angle between the two triangular mesh units.

[0115] As a preferred implementation, the feature edge rearrangement module is further used for:

[0116] S51, randomly select a characteristic edge as the current edge;

[0117] S52, obtaining two vertex indexes of the current edge;

[0118] S53, querying two other feature edges containing the vertex index, and connecting them with the current edge to obtain a new current edge, wherein different edges are connected by vertices with the same vertex index;

[0119] S54, repeat steps S52-S53 until the two vertex indexes of the current edge are the same, and a first characteristic edge set is obtained;

[0120] S55. Repeat steps S51-S54 on the remaining feature edges to obtain a second feature edge set.

[0121] As a preferred implementation, in the axis calculation module, the center of the circle is determined by the following method: randomly selecting three vertices in the feature edge set to determine a triangle, and using the center of the circumscribed circle of the triangle as the center of the bottom surface of the cylindrical component.

[0122] Embodiment three:

[0123] An electronic device comprises a processor and a storage device, wherein the storage device stores a plurality of instructions, and the processor is used to read the plurality of instructions in the storage device and execute the above method.

[0124] The beneficial effects of the present invention are further illustrated by comparative tests below.

[0125] A cylindrical component with a radius of r = 5 cm and a height of h = 10 cm was used for measurement and calculation. Table 1 shows the coordinate values ​​of the bottom circle center obtained by theoretical calculation under three scenarios and the coordinate values ​​of the bottom circle center obtained by the method provided by the present invention, and the measurement error is calculated. The error measurement calculation formula is: measurement error = maximum deviation value / radius.

[0126] Table 1

[0127]

[0128] The data in this table is tested and the deviation between the actual data and the theoretical data is about 0.2%. It can be seen from the above table that the cylindrical axis data calculated by this method has a small deviation from the theoretical value, which can reduce the problems caused by the axis error in actual use. For example, the error caused by manually adding the wheel axis in the calculation of the external fluid domain of the car model is large. The axis calculated by this method has a high accuracy, which can ensure the force balance of the wheel in the high-speed motion state, so that the speed can reach a stable state, and improve the accuracy of the calculation of the external fluid domain data of the car model in the high-speed motion state.

[0129] The cylindrical component axis recognition method, device and equipment for CFD provided in this embodiment can realize automatic recognition of the cylindrical component axis by extracting the surface mesh and rearranging the characteristic edges therein to calculate the axis of the cylindrical component. There is no need to manually input the reference point and direction of the axis through human-computer interaction in the model preprocessing stage, which effectively improves the efficiency of simulation calculation; at the same time, the automatic recognition method can obtain higher recognition accuracy, and the recognition measurement error is less than 0.2%, especially for the axis that is not parallel to any coordinate axis of the coordinate system, the accuracy improvement is more obvious compared with the accuracy obtained by human-computer interaction; this method improves the accuracy of axis recognition while improving efficiency, and provides a better user experience.

[0130] It should be understood that in the embodiments of the present application, the processor referred to may be a central processing unit (CPU), and the processor may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0131] The storage device may include a read-only memory, a flash memory, and a random access memory, and provides instructions and data to the processor. A part or all of the memory may also include a nonvolatile random access memory.

[0132] It should be understood that the above-mentioned integrated module / unit, if implemented in the form of a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on such an understanding, the present application implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The above-mentioned computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the above-mentioned computer program includes computer program code, and the above-mentioned computer program code can be in source code form, object code form, executable file or some intermediate form. The above-mentioned computer-readable medium may include: any entity or device capable of carrying the above-mentioned computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the above-mentioned computer-readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction.

[0133] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

[0134] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for identifying the axis of a cylindrical component for CFD, characterized in that: The method comprises the following steps: S1. Obtain the mesh of the cylindrical component; S2. extracting a surface mesh set based on the cylindrical component mesh; S3, triangulating the surface mesh set; S4, identifying feature edges of the triangulated surface mesh set; S5, dividing the identified feature edges into two sets, each feature edge set is used to represent a bottom surface of the cylindrical component; S6, determining the centers of the two bottom surfaces of the cylindrical component based on the characteristic edge set, and then calculating the axis of the cylindrical component; Step S4 includes: Perform the following operations on all triangular mesh units in the triangulated surface mesh set: traverse all edges in the triangular mesh units, calculate the angle between two triangular mesh units where each edge is located, if the angle is less than a preset angle, the edge is a feature edge, otherwise it is not; Step S5 includes: S51, randomly select a characteristic edge as the current edge; S52, obtaining two vertex indexes of the current edge; S53, querying two other feature edges containing the vertex index, and connecting them with the current edge to obtain a new current edge, wherein different edges are connected by vertices with the same vertex index; S54, repeat steps S52-S53 until the two vertex indexes of the current edge are the same, and a first characteristic edge set is obtained; S55. Repeat steps S51-S54 on the remaining feature edges to obtain a second feature edge set.

2. The method according to claim 1, characterized in that Step S2 includes: The following operation is performed on all mesh units in the cylindrical component mesh: all faces in the mesh unit are traversed to determine whether there are other mesh units containing the same face, if so, the face is not a surface mesh, otherwise the face is a surface mesh.

3. The method according to claim 2, characterized in that If the difference between the vertex index arrays of two faces is an empty set, then the two faces are the same.

4. The method according to claim 1, characterized in that: Step S3 includes: The following operations are performed on all mesh units in the surface mesh set: determine whether the mesh unit is a triangular mesh; if not, select any vertex of the mesh unit, and connect all vertices that are not adjacent to the vertex to the vertex, respectively, to split the mesh unit into at least two triangular meshes.

5. The method according to claim 1, characterized in that The angle between two triangular mesh elements is calculated as follows: According to the order of the vertex index of the triangular mesh unit and the right-hand screw rule, two triangular mesh unit normals are obtained respectively; Calculating the normal angle between two normal lines of the triangular mesh unit; The supplementary angle of the normal angle is calculated as the angle between the two triangular mesh units.

6. The method according to claim 1, characterized in that The center of the circle is determined by the following method: randomly selecting three vertices in the characteristic edge set to determine a triangle, and taking the center of the circumscribed circle of the triangle as the center of the bottom surface of the cylindrical component.

7. A cylindrical component axis identification device for CFD, characterized in that: include: A mesh acquisition module, used to acquire the mesh of cylindrical components; A surface mesh extraction module, used for extracting a surface mesh set based on the cylindrical component mesh; A triangulation module, used for triangulating the surface mesh set; The feature edge recognition module is used to perform feature edge recognition on the triangulated surface mesh set, including performing the following operations on all triangular mesh units in the triangulated surface mesh set: traversing all edges in the triangular mesh unit, calculating the angle between two triangular mesh units where each edge is located, if the angle is less than a preset angle, the edge is a feature edge, otherwise it is not; The feature edge rearrangement module is used to divide the identified feature edges into two sets, each feature edge set is used to represent a bottom surface of the cylindrical component, including the following steps: S51, randomly select a characteristic edge as the current edge; S52, obtaining two vertex indexes of the current edge; S53, querying two other feature edges containing the vertex index, and connecting them with the current edge to obtain a new current edge, wherein different edges are connected by vertices with the same vertex index; S54, repeat steps S52-S53 until the two vertex indexes of the current edge are the same, and a first characteristic edge set is obtained; S55, repeatedly executing steps S51-S54 on the remaining characteristic edges to obtain a second characteristic edge set; The axis calculation module determines the centers of the two bottom surfaces of the cylindrical component based on the characteristic edge set, and then calculates the axis of the cylindrical component.

8. An electronic device comprising a processor and a storage device, characterized in that: The storage device stores a plurality of instructions, and the processor is used to read the plurality of instructions in the storage device and execute the method according to claims 1-6.

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