ICEM grid division method based on accurately captured curvature change

Abstract

The invention discloses an ICEM grid division method based on accurate capture curvature change, and relates to the field of engineering design. In order to solve the technical problems in the prior art that negative grids and grid distortion are easily generated and a grid division result is discontinuous or incomplete when an existing structured grid division technology is used for coping with a complex geometric structure, the technical scheme provided by the invention comprises the following steps: naming an initial part of a preset model; drawing an overall segmentation line of the grid; the correlation points in the two-dimensional plane are subjected to constraint processing, so that each correlation point is perpendicular to the Z axis; setting an auxiliary point in each two-dimensional plane section of the model, and constructing a surrounding line for processing a geometric overlapping region; dividing the overlapped geometric model region, adjusting the positions of points and lines to avoid a cross model, and ensuring that the points and the lines are aligned with the ZX axis to form regions which do not interfere with each other; and deleting the auxiliary points and the surrounding lines, and aligning all the vertexes with the ZX plane. The method is suitable for the work of computational fluid dynamics analysis.

Description

Technical Field

[0001] This paper relates to the field of engineering design, and particularly to the problem of structured meshing of complex geometric shapes, and proposes a new meshing method. Background Art

[0002] In the field of engineering design and numerical calculation, structured meshing is a key step in fluid simulation and computational fluid dynamics (CFD) analysis. High-quality meshing has an important impact on the accuracy and stability of the calculation results, especially in simulations involving complex geometric shapes, where the quality of meshing directly determines the accuracy of the simulation. At present, mainstream meshing tools on the market such as ICEM, Gambit and Ansys Meshing are widely used in meshing. Among them, ICEM has been widely recognized by engineers for its high flexibility and powerful customization functions, especially when dealing with regular geometric shapes.

[0003] In the prior art, commonly used structured meshing methods include O-type, C-type, Y-type and other segmentation methods. These methods are usually able to quickly generate high-quality meshes when dealing with simple geometric structures, such as cylindrical, square and other regular models, and show good computational efficiency and convergence in CFD simulations. However, when faced with more complex geometric shapes, such as models with drastic changes in curvature, numerous internal details, and overlapping of multiple physical models, traditional meshing methods are unable to cope with the situation. Specifically, these methods are prone to mesh distortion and even negative mesh generation when dealing with highly complex geometric structures, which can lead to unstable and inaccurate numerical simulation results, and even prevent the calculation from proceeding normally.

[0004] For example, in aerospace engineering, when it comes to simulation analysis of complex aerodynamic shapes, traditional O-type or C-type segmentation methods often require a lot of manual intervention from engineers to correct the mesh quality because they cannot accurately capture complex curvature changes and fine geometric features. In the flow simulation inside the cylinder of an automobile engine, since the geometric structure involves multiple detailed features, the existing segmentation technology is not only time-consuming, but also the generated mesh quality is difficult to meet the requirements, which seriously affects the simulation accuracy and efficiency. In addition, when dealing with physical models with front-to-back overlapping characteristics, traditional mesh segmentation methods have difficulty in effectively identifying overlapping areas, resulting in discontinuous or incomplete segmentation results, affecting the credibility of numerical simulations.

[0005] ICEM is a commonly used meshing tool in the market. Although it provides a variety of meshing strategies and powerful customization capabilities, engineers still need to spend a lot of time on manual adjustments and quality repairs when faced with complex geometric structures, especially those with large curvature or geometric overlap. This not only increases the workload, but also requires engineers to have high professional skills, making it difficult to ensure the consistency and high quality of meshing.

[0006] In summary, the existing structured meshing technology faces the following problems when dealing with complex geometric structures:

[0007] 1. It is difficult to deal with areas with drastic curvature changes while maintaining mesh quality, and it is easy to produce negative meshes and mesh distortion.

[0008] 2. Unable to effectively handle the overlapping parts of the geometric model, resulting in discontinuous or incomplete meshing results.

[0009] 3. A lot of manual intervention is required to ensure the quality of the mesh, which results in a heavy workload for engineers and affects the efficiency and accuracy of engineering design.

[0010] Therefore, for structured meshing with complex geometric shapes and curvature changes, there is an urgent need for a meshing method that can automatically and efficiently generate high-quality meshes to reduce engineers' manual operations, improve the success rate of meshing and mesh quality, and solve the shortcomings of existing technologies. Summary of the invention

[0011] In order to solve the technical problems existing in the prior art, the existing structured meshing technology is prone to generate negative meshes and mesh distortion when dealing with complex geometric structures, and will cause discontinuous or incomplete meshing results, as well as a heavy workload for engineers, the technical solution provided by the present invention is:

[0012] The ICEM meshing method is based on accurately capturing the curvature changes. The method includes:

[0013] Steps to name the initial part of the preset model and draw the overall dividing lines of the mesh;

[0014] A step of constraining the associated points in the two-dimensional plane so that each of the associated points is perpendicular to the Z axis;

[0015] A step of setting auxiliary points in each of the two-dimensional plane segments of the model and constructing bounding lines for processing geometric overlapping areas;

[0016] The step of dividing the overlapping geometric model area, adjusting the position of the points and lines to avoid the intersecting model, and ensuring that the points and lines are aligned with the ZX axis to form areas that do not interfere with each other;

[0017] The auxiliary points and enclosing lines are deleted to align all vertices with the ZX plane.

[0018] Furthermore, a preferred embodiment is provided, wherein the overall dividing line enables each two-dimensional plane layer to have a divisible arc and boundary.

[0019] Furthermore, a preferred implementation is provided, in which 1 / 4 split points are used to perform constraint processing on associated points in the two-dimensional plane.

[0020] Furthermore, a preferred embodiment is provided, wherein the setting of the auxiliary points includes adding a plurality of auxiliary points in each two-dimensional plane segment, and constructing an enclosing line by a custom rule.

[0021] Furthermore, a preferred embodiment is provided, in which the point line on the Z axis is fine-tuned using the Index Control function to adjust the position of the point line.

[0022] Furthermore, a preferred embodiment is provided, which also includes the step of evaluating the grid according to preset evaluation conditions before deleting the auxiliary points and the encircling lines.

[0023] Based on an ICEM meshing device that accurately captures curvature changes, the method includes:

[0024] A module that names the initial part of the preset model and draws the overall dividing lines of the grid;

[0025] A module for constraining the associated points in the two-dimensional plane so that each of the associated points is perpendicular to the Z axis;

[0026] A module for processing geometric overlapping areas by setting auxiliary points in each of the two-dimensional plane segments of the model and constructing bounding lines;

[0027] The overlapping geometric model area is segmented, and the position of the points and lines is adjusted to avoid the intersecting model, while ensuring that the points and lines are aligned with the ZX axis to form modules of the area that do not interfere with each other;

[0028] A module in which the auxiliary points and enclosing lines are deleted to align all vertices with the ZX plane.

[0029] A computer storage medium is used to store a computer program. When the computer reads the computer program, the computer executes the method described.

[0030] A computer includes a processor and a storage medium. When the processor reads a computer program stored in the storage medium, the computer executes the method described.

[0031] The computer program product, as a computer program, implements the method described when the computer program is executed.

[0032] Compared with the prior art, the technical solution provided by the present invention is beneficial in that:

[0033] By adopting the method of initial part naming and overall dividing line drawing, the mesh of each two-dimensional plane layer can accurately capture geometric details and turning points, effectively improving the basic quality of mesh division. Compared with traditional processes that require manual operation, the degree of automation is significantly improved, reducing the possibility of human error.

[0034] By constraining the associated points and setting the 1 / 4 split point method, the accuracy of the mesh in the curvature change area is ensured, and the occurrence of negative mesh and mesh distortion is avoided. Compared with the manual intervention in the prior art, this method provides a more systematic constraint strategy and improves the stability and consistency of the overall mesh division.

[0035] The setting of auxiliary points and the construction of encircling lines provide an effective means to solve the geometric overlapping areas. By measuring the minimum bend line and constructing auxiliary points and encircling lines in each plane segment, the continuity and integrity of the mesh division are ensured. Compared with the problem of difficult mesh generation in overlapping areas of traditional technologies, this method significantly improves the processing ability of complex geometric models.

[0036] When dividing overlapping areas, we manually adjust the position of points and lines to avoid intersecting models, and use the Index Control function to ensure that each two-dimensional plane is aligned with the ZX axis, thus forming areas that do not interfere with each other and reducing interference problems in mesh generation. Although this method is cumbersome to operate, it provides higher control accuracy and quality assurance compared to traditional automatic division technology.

[0037] Finally, the quality and uniformity of meshing are further improved by deleting the target block and ensuring that the vertices are aligned with the ZX plane. Compared with the frequent occurrence of negative meshes in the prior art, this operation effectively avoids the negative mesh problem, making the final mesh quality more reliable and suitable for high-precision numerical simulation tasks.

[0038] Suitable for computational fluid dynamics (CFD) analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the associated point constraint;

[0040] Figure 2 It is a method for dealing with complex geometric models and front-to-back overlaps;

[0041] Among them, 1-arc boundary attachment point, 2-1 / 4 dividing point, 3-ZX plane alignment line, 4-overall dividing line, 5-actual arc of the model, 6-bending line, 7-custom auxiliary point, 8-minimum bending line, 9-Z axis right alignment line, 10-overlapping dividing area, 11-Z axis left alignment line. DETAILED DESCRIPTION

[0042] In order to make the advantages and benefits of the technical solution provided by the present invention more clearly reflected, the technical solution provided by the present invention is now further described in detail with reference to the accompanying drawings, specifically:

[0043] Embodiment 1: This embodiment provides an ICEM meshing method based on accurately capturing curvature changes, the method comprising:

[0044] Step 4 of naming the initial part of the preset model and drawing the overall dividing line of the grid;

[0045] A step of constraining the associated points in the two-dimensional plane so that each of the associated points is perpendicular to the Z axis;

[0046] A step of setting auxiliary points in each of the two-dimensional plane segments of the model and constructing bounding lines for processing geometric overlapping areas;

[0047] The step of dividing the overlapping geometric model area, adjusting the position of the points and lines to avoid the intersecting model, and ensuring that the points and lines are aligned with the ZX axis to form areas that do not interfere with each other;

[0048] The auxiliary points and enclosing lines are deleted to align all vertices with the ZX plane.

[0049] Step 1: Naming the initial parts and drawing the overall dividing line 4

[0050] Brief description: First, name the initial part of the model and draw the overall dividing line 4 according to the traditional segmentation method.

[0051] In the ICEM environment, each part of the model is initially named. For example, the bend line 6 and its diagonal position in the cylindrical shape with curvature need to be marked. Next, each two-dimensional plane layer of the model is segmented along the Z axis according to the traditional segmentation method to ensure that each segmentation layer can accurately capture the geometric details and turning points. The goal of this step is to lay the foundation for subsequent meshing and ensure that each two-dimensional plane layer has segmentable arcs and boundaries.

[0052] Step 2: Constraints and segmentation point settings for associated points

[0053] Brief description: Use 1 / 4 division point 2 to constrain the associated points to ensure the accuracy of mesh division.

[0054] In order to avoid negative meshes and division failures in areas with large curvature changes, key points are selected for constraints in each 2D plane layer. By setting the 1 / 4 division point 2, these points can be effectively associated with the actual arc of the model. At the same time, in order to ensure the quality of the mesh after division, each associated point must be perpendicular to the Z axis, that is, the points on the 2D plane need to be aligned with the actual arc on the ZX plane. This ensures that each 2D mesh after division is uniform and of high quality.

[0055] Step 3: Setting auxiliary points and building encircling lines

[0056] Brief description: Set auxiliary points on each 2D plane segment of the model and construct bounding lines to handle complex geometric overlapping areas.

[0057] For the front-to-back overlapping geometric model, the length of the minimum bend line 8 is first measured, which provides data support for the subsequent setting of auxiliary points. In each two-dimensional plane segment, two auxiliary points are set outward along the two ends of the actual arc boundary, and another auxiliary point is set in the middle to form an encircling line. The setting of these auxiliary points needs to take into account the length of the minimum bend line 8 to avoid intersections between auxiliary points, ensure the continuity of the encircling line and the accuracy of mesh division.

[0058] Step 4: Overlapping area segmentation and manual adjustment

[0059] Brief description: The overlapping area is segmented and the point and line positions are manually adjusted to avoid intersecting models.

[0060] When dealing with overlapping segmentation areas, the position of the points and lines on the Z axis is manually adjusted to avoid intersecting models. In the specific operation, with the help of the Index Control function of ICEM, only the points and lines of a single two-dimensional plane are adjusted to ensure that the points and lines of each two-dimensional plane are aligned with the ZX axis to form a non-interfering area. Although this manual adjustment is cumbersome, it can effectively avoid the generation of negative grids and improve the quality of the final grid.

[0061] Step 5: Delete the target block and align it with the vertex

[0062] Brief description: After completing meshing, delete the target block and ensure that all vertices are aligned with the ZX plane.

[0063] After all auxiliary points and encircling lines are set, the redundant target blocks in the model are deleted to ensure the integrity and quality of the mesh division. It is particularly important to note that the vertices on each two-dimensional plane layer perpendicular to the Z axis must be aligned with the ZX plane. In this way, the quality of mesh division can be effectively improved to ensure that the mesh after division is uniform and has no negative mesh problems.

[0064] Embodiment 2: This embodiment further limits the ICEM meshing method based on accurately capturing curvature changes provided in embodiment 1. The overall dividing line 4 enables each two-dimensional plane layer to have divisible arcs and boundaries.

[0065] Implementation method three: This implementation method further limits the ICEM meshing method based on accurately capturing curvature changes provided in implementation method one, and uses 1 / 4 split point 2 to constrain the associated points in the two-dimensional plane.

[0066] Implementation method 4: This implementation method further limits the ICEM meshing method based on accurately capturing curvature changes provided in implementation method 1. The setting of the auxiliary points includes adding multiple auxiliary points in each two-dimensional plane segment and constructing enclosing lines through custom rules.

[0067] Implementation method 5: This implementation method further limits the ICEM meshing method based on accurately capturing curvature changes provided in implementation method 1, and uses the Index Control function to fine-tune the points and lines on the Z axis to adjust the positions of the points and lines.

[0068] Implementation method six: This implementation method further limits the ICEM meshing method based on accurately capturing curvature changes provided in implementation method one, and also includes the step of evaluating the mesh according to preset evaluation conditions before deleting the auxiliary points and encircling lines.

[0069] Embodiment 7: This embodiment provides an ICEM meshing device based on accurately capturing curvature changes, and the method includes:

[0070] Name the initial part of the preset model and draw the overall dividing line 4 of the grid;

[0071] A module for constraining the associated points in the two-dimensional plane so that each of the associated points is perpendicular to the Z axis;

[0072] A module for processing geometric overlapping areas by setting auxiliary points in each of the two-dimensional plane segments of the model and constructing bounding lines;

[0073] The overlapping geometric model area is segmented, and the position of the points and lines is adjusted to avoid the intersecting model, while ensuring that the points and lines are aligned with the ZX axis to form modules of the area that do not interfere with each other;

[0074] A module in which the auxiliary points and enclosing lines are deleted to align all vertices with the ZX plane.

[0075] Embodiment 8: This embodiment provides a computer storage medium for storing a computer program. When the computer reads the computer program, the computer executes the method provided in embodiment 1.

[0076] Embodiment 9: This embodiment provides a computer, including a processor and a storage medium. When the processor reads a computer program stored in the storage medium, the computer executes the method provided in embodiment 1.

[0077] Embodiment 10: This embodiment provides a computer program product, which is a computer program. When the computer program is executed, the method provided in embodiment 1 is implemented.

[0078] Implementation Method XI: Combination Figure 1-2 This embodiment is described in detail by using specific examples to further describe the technical solution provided above. Specifically:

[0079] This implementation method effectively solves the meshing problem of ICEM software in processing complex geometric shapes, especially those with curvature, corners, and front-to-back overlap of physical models, by proposing a new structured meshing method. This method uses the method of associating custom distribution regular points with grid points, and setting enclosing points and lines according to the two-dimensional plane of complex graphics, and transforms the idea of ​​dividing a three-dimensional complex body into a two-dimensional plane. It significantly improves the success rate and quality of meshing, avoids the occurrence of negative grids in the process of dividing structured grids, provides engineers with a new and reliable method for meshing, reduces the workload, improves work efficiency, and improves the accuracy and reliability of numerical simulation, effectively solving a major problem in the meshing process of Fluent numerical calculation pre-processing.

[0080] This embodiment involves the ICEM meshing method. After completing the naming of the initial Part, first draw the overall dividing line 4 that conforms to the actual arc 5 of the model according to the traditional dividing method. For example, the model in the first figure is a cylinder with curvature, and there are turns at the bending line 6 and its diagonal corners. When dividing the whole, it is necessary to divide each two-dimensional plane layer of the model in sequence along the Z-axis direction. This ensures that the mesh accurately captures every detail and turning point after division. This overall division process is very important, especially for models with curvature. Negative meshes and failure to successfully divide the mesh are very likely to occur in places where the curvature changes greatly. In order to further avoid the above situation, further constraints on the associated points should be adopted. The 1 / 4 dividing point 2 method can be used to perform constraint processing well. When you subsequently execute the point-line association command, directly associate the arc boundary attachment point 1 with the actual arc 5 of the model. However, in order to ensure good mesh quality, the associated point line must be perpendicular to the Z axis. When using point-line alignment, each two-dimensional plane where the model is located must be aligned with the actual arc in the ZX plane 3. After using the above method, you can directly delete the target block to complete the mesh division.

[0081] In the description of the second figure, another division method is introduced. A new method is provided for physical models with complex geometric models with front and back overlap. The overall division method is the same as above, except that when there are bend lines with too small curvature or small size in this model, the length of the minimum bend line 8 must be measured first to provide data support for the division of the later grid custom auxiliary points 7. Then, for the two end points of the actual arc boundary of each two-dimensional plane segment in the Z-axis direction, two auxiliary points are made outward respectively. After making an auxiliary point in the middle of the actual arc, on the basis of this point, an auxiliary point with the minimum turning line 7 distance is made outward, and these three points are connected to form an auxiliary line. This method is used to make auxiliary point lines at each two-dimensional plane. For the overlapping partition 10, the Z-axis point is manually adjusted to move to avoid the cross model, but it should be noted that when moving the point, it should always move on the model arc to ensure that each point is in a cross section, so that the middle part of the cross model forms an area that does not interfere with each other. Finally, when associating points, the vertices are directly associated with auxiliary points instead of the actual arc points of the model. This is done to divide the complex geometric model by enclosing lines, and then delete the blocks. The alignment of the subdivision lines on the left and right sides of the model is also particularly important. This is reflected in the deletion of the block. At this time, the model arc point lines need to be associated instead of auxiliary lines. That is, the auxiliary point lines are only useful when dividing the blocks in the front. After association, the Z-axis right alignment line 9 and the Z-axis left alignment line 11 must ensure that they are aligned with the Z-axis of the original model arc boundary attachment point to avoid negative meshes and poor mesh quality.

[0082] In the specific implementation of this embodiment, this embodiment adopts a novel ICEM meshing method, which is suitable for physical models with complex geometric shapes and curvature changes. First, this embodiment names the initial part of the model and draws the overall segmentation line 4 that conforms to the actual arc 5 of the model in a traditional segmentation method. Taking the complex cylindrical shape with curvature as an example, this embodiment notices that there is a turning point at the bending line 6 and its diagonal corners. Therefore, when the overall segmentation is performed, this embodiment sequentially segments each two-dimensional plane layer of the model in the Z-axis direction to ensure that every detail and turning point can be accurately captured after the meshing.

[0083] In the attached Figure 1 In order to solve the problem of negative grid and division difficulty that may appear in places with large curvature changes, this embodiment adopts further constraints on the associated points. Specifically, this embodiment adopts the method of 1 / 4 division point 2 for constraint processing to ensure the accuracy of mesh division. When executing the point-line association command, this embodiment directly associates the arc boundary attachment point 1 with the actual arc 5 of the model, and ensures that the associated point line is perpendicular to the Z axis, that is, each point of the two-dimensional plane is aligned with the actual arc on the same ZX plane.

[0084] In the attached Figure 2 For the case of complex geometric models and front-to-back overlap, this embodiment first measures the length of the minimum bend line 8 to provide data support for the division of the later grid custom auxiliary points 7. That is, the length of the auxiliary point is selected not to exceed the length of the minimum bend line 8, which can effectively avoid the intersection of the minimum bend area when dividing the auxiliary points and connecting the encirclement lines. Then, in each two-dimensional plane segment of the model, this embodiment makes two auxiliary points outward on the actual arc boundary points, and makes an auxiliary point in the middle of the actual arc. Based on this auxiliary point, another new auxiliary point is made outward, and these three points are connected to form an encirclement line. For the overlapping sectioning area, this embodiment uses manual adjustment of the Z-axis point to avoid the intersection model. In actual operation, the Index Control function can be used to adjust only the point line of a two-dimensional plane, and then the ZX axis alignment method is used to align the model boundary point lines. It should be ensured that a non-interference area is formed in the middle, which can effectively avoid the appearance of negative grids.

[0085] Finally, whether it is directly associated or auxiliary lines, after deleting the blocks. It is necessary to ensure that the vertices of each two-dimensional plane layer of the model perpendicular to the Z axis are on the same ZX plane. This approach seems cumbersome, but it can effectively improve the quality of the mesh. Through the above method, this implementation can effectively complete the meshing of complex geometric models and improve the quality and efficiency of meshing.

[0086] The technical solution provided by the present invention is further described in detail above through several specific implementation modes in order to highlight the advantages and benefits of the technical solution provided by the present invention. However, the several specific implementation modes described above are not intended to be used as limitations on the present invention. Any reasonable modification and improvement of the present invention, combination of implementation modes and equivalent substitution within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. ICEM meshing method based on accurately capturing curvature changes, characterized in that the method include: Steps to name the initial part of the preset model and draw the overall dividing lines of the mesh; A step of constraining the associated points in the two-dimensional plane so that each of the associated points is perpendicular to the Z axis; A step of setting auxiliary points in each of the two-dimensional plane segments of the model and constructing bounding lines for processing geometric overlapping areas; The step of dividing the overlapping geometric model area, adjusting the position of the points and lines to avoid the intersecting model, and ensuring that the points and lines are aligned with the ZX axis to form areas that do not interfere with each other; The auxiliary points and enclosing lines are deleted to align all vertices with the ZX plane.

2. The ICEM meshing method based on accurately capturing curvature changes according to claim 1 is characterized in that: The overall dividing line enables each two-dimensional plane layer to have a divisible arc and boundary.

3. The ICEM meshing method based on accurately capturing curvature changes according to claim 1 is characterized in that: The associated points in the two-dimensional plane are constrained using 1 / 4 split points.

4. The ICEM meshing method based on accurately capturing curvature changes according to claim 1 is characterized in that: The setting of the auxiliary points includes adding a plurality of auxiliary points in each two-dimensional plane segment and constructing an enclosing line by a custom rule.

5. The ICEM meshing method based on accurately capturing curvature changes according to claim 1 is characterized in that: Use the Index Control function to fine-tune the dot line on the Z axis to adjust the dot line position.

6. The ICEM meshing method based on accurately capturing curvature changes according to claim 1 is characterized in that: The method further includes the step of evaluating the grid according to preset evaluation conditions before deleting the auxiliary points and the encircling lines.

7. An ICEM meshing device based on accurately capturing curvature changes, characterized in that the method include: A module that names the initial part of the preset model and draws the overall dividing lines of the grid; A module for constraining the associated points in the two-dimensional plane so that each of the associated points is perpendicular to the Z axis; A module for processing geometric overlapping areas by setting auxiliary points in each of the two-dimensional plane segments of the model and constructing bounding lines; The overlapping geometric model area is segmented, and the position of the points and lines is adjusted to avoid the intersecting model, while ensuring that the points and lines are aligned with the ZX axis to form modules of the area that do not interfere with each other; A module in which the auxiliary points and enclosing lines are deleted to align all vertices with the ZX plane.

8. A computer storage medium for storing a computer program, characterized in that: When the computer reads the computer program, the computer executes the method of claim 1.

9. A computer, comprising a processor and a storage medium, characterized in that: When the processor reads the computer program stored in the storage medium, the computer executes the method of claim 1 .

10. A computer program product, being a computer program, characterized in that When the computer program is executed, the method of claim 1 is implemented.

Images