A meshing method for a multi-inclined air film hole tension-compression structure

Abstract

The application relates to the technical field of strength simulation modeling, and discloses a grid division method of a multi-inclined air film hole tension-compression structure, which comprises the following steps: a geometric model containing the multi-inclined air film hole tension-compression structure is established, and the surface of the geometric model is divided into a hole-containing rectangular extended area and a non-hole-containing area; the hole-containing rectangular extended area is divided into four symmetrical sub-areas, and a circumferential grid line gradually changes around an elliptical hole in each sub-area from a hole wall to an outer edge by adopting an equal ratio sequence interval control; plane grid division is completed on the two types of areas; and finally, hexahedral grids are generated by carrying out three-dimensional grid sweeping on the geometric model according to the plane grids divided on the surface of the geometric model. The grids divided by the method are regular in shape and uniform in size, can guarantee high accuracy and reliability of subsequent finite element calculation, realize smooth transition between the vicinity of the elliptical hole and the far field area, avoid calculation errors caused by grid distortion on the hole edge, and can further improve the calculation accuracy and stability of finite element simulation.

Description

Technical Field

[0001] This invention relates to the field of strength simulation modeling technology, and discloses a mesh generation method for a multi-oblique air film hole tension-compression structure. Background Technology

[0002] In engineering fields such as aerospace turbine blade film cooling holes and heat exchanger design, structures with dense arrays of oblique or irregularly shaped holes are widely used. Therefore, studying mesh generation methods for oblique holes is of great significance for accurately analyzing their mechanical behavior. When performing numerical simulations on such structures, the quality of the mesh directly determines the accuracy and convergence speed of the calculation.

[0003] Traditional unstructured meshes (such as tetrahedral meshes) are easy to generate, but they are prone to large errors near the hole wall boundaries and have a large number of nodes, resulting in high computational resource consumption. On the other hand, traditional structured mesh generation methods (such as hexahedral meshes) often cannot directly perform sweep operations when dealing with complex topologies such as porous or oblique holes, leading to mesh generation failure or excessive mesh distortion. Summary of the Invention

[0004] The purpose of this invention is to provide a mesh generation method for a multi-oblique air film hole tension-compression structure, which can ensure that the generated mesh has a regular shape and uniform size, and can guarantee the high accuracy and reliability of subsequent finite element calculations. It achieves a smooth transition between the vicinity of the elliptical hole and the far field region, and avoids the calculation error introduced by the hole edge mesh distortion.

[0005] To achieve the above-mentioned technical effects, the technical solution adopted by the present invention is as follows:

[0006] A mesh generation method for a multi-oblique film-forming tension-compression structure includes: Establish a geometric model that includes a multi-oblique film-forming tension-compression structure; Centered on the elliptical opening formed by each oblique hole on the surface of the geometric model, multiple rectangular extended regions are formed on the surface of the geometric model, the length of the rectangular extended regions being parallel to the major axis of the elliptical opening; Using the boundary of each rectangular expansion region as a cutting plane, the surface of the geometric model is divided to form multiple rectangular expansion regions with elliptical openings and non-porous regions without elliptical openings. The geometric model surface is divided into a rectangular extended region with holes and a region without holes according to a preset mesh aspect ratio range. When dividing the rectangular extended region with holes into planar meshes, the rectangular extended region with holes is divided into four symmetrical sub-regions along the major and minor axes of the elliptical hole. The circumferential mesh lines around the elliptical hole are gradually changed from the hole wall to the outer edge using a geometric series spacing. Based on the planar mesh divided on the surface of the geometric model, a three-dimensional mesh sweep is performed along the axial direction of the oblique holes to generate a hexahedral mesh for the geometric model of the multi-oblique air film hole tension-compression structure.

[0007] Furthermore, the length of the rectangular extended region containing the hole is more than 1.2 times the major axis of the elliptical hole, the width of the rectangular extended region containing the hole is more than 1.8 times the minor axis of the elliptical hole, and the rectangular extended regions of two adjacent elliptical holes do not overlap.

[0008] Furthermore, the gradient equation for the circumferential grid lines around the elliptical aperture, controlled by a geometric series spacing from the aperture wall to the outer edge in each sub-region, is as follows: ,in This represents the distance from the first circumferential grid line at the edge of the elliptical aperture to the edge of the elliptical aperture. This is the shortest distance from the edge of the elliptical aperture in the sub-region to the edge of the rectangular extended region containing the aperture. This represents the magnification ratio of the spacing between adjacent circumferential grid lines from the hole wall to the outer edge. The range of values ​​is , The number of design mesh layers from the edge of the elliptical aperture to the edge of the rectangular extended region containing the aperture.

[0009] Furthermore, for each sub-region, the circumferential grid lines around the elliptical aperture are gradually varied using a geometric series spacing from the aperture wall to the outer edge. After the circumferential grid lines are divided, the number of grid partitions at the edge of the elliptical aperture is determined according to... Configure the settings, including The number of grid partitions at the edge of the elliptical aperture. This represents the number of segments of the circumferential grid line of the sub-region along the length-direction boundary line of the corresponding quarter rectangle. This represents the number of segments of the circumferential grid line of the subregion along the width-direction boundary line of the corresponding quarter rectangle.

[0010] Furthermore, when dividing the non-perforated region into planar meshes according to the preset mesh aspect ratio range, the mesh nodes of the non-perforated region and the mesh nodes of the perforated rectangular extension region are controlled to be in the same position on the shared geometric boundary between the non-perforated region and the perforated rectangular extension region.

[0011] Furthermore, when generating a hexahedral mesh by three-dimensional mesh sweeping of the geometric model of the multi-oblique air film hole tension-compression structure along the axial direction of the oblique holes, the thickness direction of the geometric model is divided into meshes using the equal division method.

[0012] Furthermore, the number of mesh layers in the thickness direction ,in For the floor function, The average length of the planar grid of the edge lines of all rectangular extended regions containing holes on the surface of the geometric model along the major axis of the elliptical hole is given. The average length of the planar mesh along the minor axis of the elliptical aperture is given by the broadband direction of the edge lines of all the wide rectangular extended regions containing holes on the surface of the geometric model. The angle between the axis of the inclined hole and the surface of the geometric model is given. The thickness of the geometric model is given.

[0013] Compared with the prior art, the beneficial effects of this invention are: 1. This invention can ensure that the divided mesh has a regular shape and uniform size, and can guarantee the high accuracy and reliability of subsequent finite element calculations.

[0014] 2. This invention achieves a smooth transition between the vicinity of the elliptical aperture and the far-field region by controlling the gradual change of the grid lines through a geometric sequence, avoiding the calculation error introduced by the grid distortion at the aperture edge, and further improving the calculation accuracy and stability of finite element simulation. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the multi-oblique air film hole tension-compression structure in the embodiment; Figure 2 This is a schematic diagram of the rectangular extended area in the embodiment; Figure 3 This is a schematic diagram of a single sub-region in the embodiment; Figure 4 This is a schematic diagram of the grid division result for a single sub-region in the embodiment; Figure 5 This is a schematic diagram showing the meshing results of the rectangular extended region with holes and the non-hole region in the embodiment. Figure 6 This is a schematic diagram of the mesh division result along the thickness direction of the multi-oblique air film hole tension-compression structure in the embodiment; Among them, 1. Multi-oblique air film pore tension and compression structure; 101. Oblique hole; 2. Rectangular extension region with hole; 201. Sub-region; 3. Non-pore region. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings. However, this should not be construed as limiting the scope of the above-described subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0017] Example 1 See Figures 1 to 6 A mesh generation method for a multi-oblique film-forming tension-compression structure, comprising: A geometric model of the tension-compression structure 1 containing multiple oblique air film pores is established; Centered on the elliptical opening formed by each oblique hole 101 on the surface of the geometric model, multiple rectangular extended regions are formed on the surface of the geometric model, the length of the rectangular extended regions being parallel to the major axis of the elliptical opening; Using the boundary of each rectangular expansion region as a cutting plane, the surface of the geometric model is divided to form multiple rectangular expansion regions 2 containing elliptical openings and non-porous regions 3 without elliptical openings. According to the preset mesh aspect ratio range, the rectangular extended region 2 with holes and the non-rectangular extended region 3 on the surface of the geometric model are divided into meshes respectively; wherein, when dividing the planar mesh of the rectangular extended region 2 with holes, the rectangular extended region 2 with holes is divided into four symmetrical sub-regions 201 along the major axis and minor axis of the elliptical hole, and each sub-region 201 adopts a geometric series spacing to control the gradual change of the circumferential mesh lines around the elliptical hole from the hole wall to the outer edge; Based on the planar mesh divided on the surface of the geometric model, a three-dimensional mesh sweep is performed on the geometric model of the multi-oblique air film hole tension and compression structure 1 along the axial direction of the oblique hole 101 to generate a hexahedral mesh.

[0018] In this embodiment, a geometric model containing a multi-oblique air film tension-compression structure 1 is established. Then, taking the elliptical opening formed by each oblique hole 101 on the surface of the geometric model as the center, a rectangular extension region with its length direction parallel to the major axis of the elliptical opening is formed to divide the surface of the geometric model into a rectangular extension region with holes 2 and a non-porous region 3. Subsequently, planar meshing is performed on the two types of regions respectively. The rectangular extension region with holes 2 is divided into four symmetrical sub-regions 201 along the major and minor axes of the elliptical opening. Each sub-region 201 uses a geometric series spacing to control the gradual change of the circumferential mesh lines around the elliptical opening from the hole wall to the outer edge. Finally, based on the planar mesh divided on the surface of the geometric model, a three-dimensional mesh sweep is performed on the geometric model along the axial direction of the oblique hole 101 to generate a hexahedral mesh. The mesh generated by this method has a regular shape and uniform size, which can ensure the high accuracy and reliability of subsequent finite element calculations. At the same time, the gradual change of the mesh lines controlled by the geometric sequence realizes a smooth transition between the vicinity of the elliptical aperture and the far field region, avoiding the calculation error introduced by the mesh distortion at the aperture edge, and can further improve the calculation accuracy and stability of finite element simulation.

[0019] Example 2 See Figures 1 to 6 A mesh generation method for a multi-oblique film-forming tension-compression structure, comprising: S1. Establish a geometric model of the tension-compression structure 1 containing multiple oblique air film holes; In this embodiment, a geometric model of the multi-oblique air film tension-compression structure 1 is established by obtaining the characteristic parameters of the multi-oblique air film tension-compression structure 1; the characteristic parameters include: the diameter of the oblique hole 101. The array spacing of adjacent oblique holes 101, and the angle between the axis of the oblique hole 101 and the surface of the multi-oblique air film hole tension-compression structure 1. The thickness of one piece of multi-oblique air film hole tension-compression structure .

[0020] S2. Taking the elliptical opening formed by each oblique hole 101 on the surface of the geometric model as the center, multiple rectangular extended regions are formed on the surface of the geometric model, and the length of the rectangular extended regions is parallel to the major axis of the elliptical opening. In this embodiment, the oblique hole 101 forms an elliptical opening on the surface of the geometric model, with a minor axis length of... Major axis length With the center point of the elliptical aperture as the origin, the boundary length of a single rectangular extended region is constrained to satisfy: The length of the rectangular expansion region 2 containing the hole is at least 1.2 times the major axis of the elliptical hole, and the width of the rectangular expansion region 2 containing the hole is at least 1.8 times the minor axis of the elliptical hole, and the rectangular expansion regions of two adjacent elliptical holes do not overlap. This completes the division of the rectangular expansion region corresponding to each elliptical hole.

[0021] S3. Using the boundary of each rectangular expansion region as a cutting plane, the surface of the geometric model is divided to form multiple rectangular expansion regions 2 containing elliptical openings and non-porous regions 3 without elliptical openings. The geometric model cutting process in this embodiment is as follows: 3.1) Establish a local coordinate system at the origin of the inclined hole 101, and construct a cutting plane containing the boundary of the rectangular extended region based on the local coordinate system; 3.2) The geometric model is divided into two parts using a cutting plane: a rectangular extended region with holes (2) and a non-porous region (3). 3.3) Combine the segmented regions into a regular topological structure to meet the requirements of subsequent hexahedral swept mesh generation.

[0022] S4. The rectangular extended region 2 with holes and the non-rectangular extended region 3 on the surface of the geometric model are divided into meshes according to the preset mesh aspect ratio range. When dividing the rectangular extended region 2 with holes into planar meshes, the rectangular extended region 2 with holes is divided into four symmetrical sub-regions 201 along the major axis and minor axis of the elliptical hole. Each sub-region 201 has a circumferential mesh line that gradually changes from the hole wall to the outer edge using a geometric series spacing. In this embodiment, during the meshing process of the rectangular extended region 2 containing the hole: The gradient equation for the circumferential grid lines around the elliptical aperture, controlled by a geometric progression spacing from the aperture wall to the outer edge, is as follows: ,in This represents the distance from the first circumferential grid line at the edge of the elliptical aperture to the edge of the elliptical aperture. This is the shortest distance from the edge of the elliptical aperture in sub-region 201 to the edge of the rectangular extended region 2 containing the aperture. This represents the magnification ratio of the spacing between adjacent circumferential grid lines from the hole wall to the outer edge. The range of values ​​is , The number of design mesh layers from the edge of the elliptical aperture to the edge of the rectangular extended region 2 containing the aperture; Each sub-region 201 uses a geometric progression spacing to control the gradual change of the circumferential grid lines around the elliptical aperture from the aperture wall outwards. After completing the circumferential grid division, the number of grid partitions at the edge of the elliptical aperture is determined according to... Configure the settings, including The number of grid partitions at the edge of the elliptical aperture. This represents the number of segments of the circumferential grid line of subregion 201 along the length-direction boundary line of the corresponding quarter rectangle. This represents the number of segments of the circumferential grid line of subregion 201 on the width-direction boundary line of the corresponding quarter rectangle; In this embodiment, to ensure the convergence speed and stress solution accuracy of the finite element calculation, and to prevent the element shape function from failing due to extreme geometric dimensions, a mandatory mesh aspect ratio threshold must be applied. The constraint equation. In this embodiment, the limit threshold is preferably set as follows: and If the aspect ratio exceeds... If the span between the long and short sides of a hexahedral element is too large, the stiffness along the short side will be excessively amplified under large loads or thermal gradients, leading to an ill-conditioned stiffness matrix. By strictly limiting the aspect ratio within this range, the outermost transition mesh can be forced to approach an ideal equiaxed square, thus ensuring the numerical stability of the overall mesh at the geometric level.

[0023] In this embodiment, when dividing the non-perforated region 3 into planar meshes according to the preset mesh aspect ratio range, the mesh nodes of the non-perforated region 3 and the mesh nodes of the perforated rectangular extension region 2 are controlled to be in the same position on the shared geometric boundary between the non-perforated region 3 and the perforated rectangular extension region 2.

[0024] S5. Based on the planar mesh divided on the surface of the geometric model, a three-dimensional mesh sweep is performed on the geometric model of the multi-oblique air film hole tension and compression structure 1 along the axial direction of the oblique hole 101 to generate a hexahedral mesh. In this embodiment, when generating a hexahedral mesh by three-dimensional mesh sweeping of the geometric model of the multi-oblique air film hole tension-compression structure 1 along the axial direction of the oblique hole 101, the thickness direction of the geometric model is divided into meshes using an equal division method, and the number of mesh layers in the thickness direction is... ,in For the floor function, The average length of the planar grid of the edge lines of all rectangular extended regions containing holes on the surface of the geometric model along the major axis of the elliptical hole is given. The average length of the planar mesh along the minor axis of the elliptical aperture is given by the broadband direction of the edge lines of all the wide rectangular extended regions containing holes on the surface of the geometric model. The angle between the axis of the inclined hole 101 and the surface of the geometric model is given. The thickness of the geometric model is given.

[0025] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A mesh generation method for a multi-oblique air film perforated tension-compression structure, characterized in that, include: Establish a geometric model that includes a multi-oblique film-forming tension-compression structure; Centered on the elliptical opening formed by each oblique hole on the surface of the geometric model, multiple rectangular extended regions are formed on the surface of the geometric model, the length of the rectangular extended regions being parallel to the major axis of the elliptical opening; Using the boundary of each rectangular expansion region as a cutting plane, the surface of the geometric model is divided to form multiple rectangular expansion regions with elliptical openings and non-porous regions without elliptical openings. The geometric model surface is divided into a rectangular extended region with holes and a region without holes according to a preset mesh aspect ratio range. When dividing the rectangular extended region with holes into planar meshes, the rectangular extended region with holes is divided into four symmetrical sub-regions along the major and minor axes of the elliptical hole. The circumferential mesh lines around the elliptical hole are gradually changed from the hole wall to the outer edge using a geometric series spacing. Based on the planar mesh divided on the surface of the geometric model, a three-dimensional mesh sweep is performed along the axial direction of the oblique holes to generate a hexahedral mesh for the geometric model of the multi-oblique air film hole tension-compression structure.

2. The mesh generation method for the multi-oblique air film pore tension-compression structure according to claim 1, characterized in that, The length of the rectangular expansion region containing the hole is more than 1.2 times the major axis of the elliptical hole, and the width of the rectangular expansion region containing the hole is more than 1.8 times the minor axis of the elliptical hole, and the rectangular expansion regions of two adjacent elliptical holes do not overlap.

3. The mesh generation method for the multi-oblique air film pore tension-compression structure according to claim 1, characterized in that, The gradient equation for the circumferential grid lines around the elliptical aperture is controlled by a geometric progression from the aperture wall to the outer edge in each sub-region. ,in This represents the distance from the first circumferential grid line at the edge of the elliptical aperture to the edge of the elliptical aperture. This is the shortest distance from the edge of the elliptical aperture in the sub-region to the edge of the rectangular extended region containing the aperture. This represents the magnification ratio of the spacing between adjacent circumferential grid lines from the hole wall to the outer edge. The range of values ​​is , The number of design mesh layers from the edge of the elliptical aperture to the edge of the rectangular extended region containing the aperture.

4. The mesh generation method for the multi-oblique air film pore tension-compression structure according to claim 3, characterized in that, Each sub-region uses a geometric progression spacing to control the gradual change of the circumferential grid lines around the elliptical aperture from the aperture wall outwards. After the circumferential grid lines are divided, the number of grid partitions at the edge of the elliptical aperture is determined according to... Configure the settings, including The number of grid partitions at the edge of the elliptical aperture. This represents the number of segments of the circumferential grid line of the sub-region along the length-direction boundary line of the corresponding quarter rectangle. This represents the number of segments of the circumferential grid line of the subregion along the width-direction boundary line of the corresponding quarter rectangle.

5. The mesh generation method for the multi-oblique air film pore tension-compression structure according to claim 1, characterized in that, When dividing the non-perforated region into planar meshes according to the preset mesh aspect ratio range, the mesh nodes of the non-perforated region and the mesh nodes of the perforated rectangular extension region are controlled to be in the same position on the shared geometric boundary between the non-perforated region and the perforated rectangular extension region.

6. The mesh generation method for the multi-oblique air film pore tension-compression structure according to claim 1, characterized in that, When generating a hexahedral mesh by three-dimensional mesh sweeping of the geometric model of the multi-oblique air film hole tension-compression structure along the axial direction of the oblique hole, the thickness direction of the geometric model is divided into meshes using the equal division method.

7. The mesh generation method for the multi-oblique air film pore tension-compression structure according to claim 6, characterized in that, Number of mesh layers in the thickness direction ,in For the floor function, The average length of the planar grid of the edge lines of all rectangular extended regions containing holes on the surface of the geometric model along the major axis of the elliptical hole is given. The average length of the planar mesh along the minor axis of the elliptical aperture is given by the broadband direction of the edge lines of all the wide rectangular extended regions containing holes on the surface of the geometric model. The angle between the axis of the inclined hole and the surface of the geometric model is given. The thickness of the geometric model is given.

Images