A blade parameterization method based on fluid-solid-grid collaborative deformation

Abstract

The present invention is a blade parameterization method based on fluid-solid mesh collaborative deformation, which belongs to the technical field of aero-engine blade shape parameterization. In view of the problems of large computational complexity and low computational efficiency in current mesh deformation methods, the method of the present invention includes constructing an initial fluid domain mesh and a solid domain mesh adapted to the blade model, introducing an O-type domain in the solid domain mesh, using a set of blade points at different blade heights on the blade as blade control points, and using Hicks-Henne type functions, circumferential offsets combined with radial basis functions to obtain the contour changes and stacking rule changes of the blade respectively, and evenly spreading the offset increments of the control points to the entire blade surface. Based on the idea of ​​structural mesh orthogonality, the deformation of the blade surface mesh is transmitted to the far end along the orthogonal direction. Compared with the traditional blade parameterization method, the present invention not only realizes the two deformation modes of fluid-solid domain blade contour and stacking rule at the same time, but also improves the deformation efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engine blade shape parameterization, and in particular to a blade parameterization method based on fluid-solid grid collaborative deformation. Background Art

[0002] With the rapid development of modern aero-engine technology, compressor performance has significantly improved. Blades, as core components of compressors, have been evolving towards high pressure ratios, high efficiency, high strength, and long life. This has led to an increasingly complex environment for compressor blades, involving the intersection of multiple disciplines, including aerodynamics, structure, strength, and reliability. In traditional multidisciplinary optimization design, updating geometric models relies on re-meshing. However, this approach carries the risk of model update failure, and re-meshing is time-consuming for complex models, reducing optimization efficiency. Therefore, a mesh parameterization method tailored to multidisciplinary problems is needed.

[0003] Currently, most mesh deformation methods for multidisciplinary problems are based on freeform deformation (FFD) technology. However, the FFD method has the problem of non-intuitive deformation. In order to obtain the target shape, a large number of control points need to be carefully arranged. Especially for special shapes such as blades, the ability to express the structure of fillets and transition surfaces is insufficient. In addition, the FFD mesh deformation method has a large computational load. For three-dimensional problems, the FFD method requires three layers of nesting, and the time complexity is O(n 3 ), as the number of control points increases due to fine-grained deformation control, the cumulative amount of three-dimensional calculations increases geometrically, and the calculation efficiency is low.

[0004] In view of this, studying a blade parameterization method that can realize grid deformation for flow field structure analysis and has high computational efficiency is of great significance for the design and application of aero-engine axial flow blade shape. Summary of the Invention

[0005] In response to the defects existing in the above-mentioned prior art, the purpose of the present invention is to provide a blade parameterization method based on fluid-solid grid collaborative deformation. This method can simultaneously realize two deformation modes of blade contour change and stacking rule change, effectively improving the deformation efficiency, thereby solving the problems existing in the background technology.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions:

[0007] A blade parameterization method based on fluid-solid-grid collaborative deformation includes the following steps:

[0008] S1: Construct the initial fluid domain mesh and solid domain mesh adapted to the blade model, and introduce the O-type domain into the solid domain mesh with the help of the topological structure of the fluid domain mesh;

[0009] S2: The leaf shape point set at different leaf height positions on the blade is used as the leaf shape control point;

[0010] S3: Based on the profile change of the blade, the Hicks-Henne function is used to perform local perturbations on the blade to obtain the geometric deviation of the blade control point, and the geometric deviation is evenly spread to the entire blade surface;

[0011] S4: In response to the changes in the overlapping regularity of the blade profile, a mapping relationship is constructed by combining the circumferential offset of the blade profile control points with the radial basis function interpolation method, and the change interpolation is evenly spread across the entire blade surface;

[0012] S5: After obtaining the blade surface node coordinate increments from steps S3-S4, the blade surface node coordinate increments are diffused in a direction away from the blade surface along the orthogonal direction of the structural grid. By setting the diffusion attenuation coefficient, the deformation during the diffusion process is attenuated to zero at the edge of the O-shaped domain.

[0013] As a further preferred embodiment of the above technical solution: in step S3, the step of diffusing the geometric deviation caused by the change in the blade profile to the entire blade surface includes:

[0014] S31: normalize the distance of the blade control point from the trailing edge of the blade along the blade;

[0015] S32: determining superposition positions at different positions of the blade profile after normalization, wherein the superposition positions are located in a flow-sensitive region uniformly distributed along the circumferential direction of the blade profile, and arranging a Hicks-Henne type function at the superposition positions to simulate geometric deviations of blade profile control points using the Hicks-Henne type function;

[0016] S33: After obtaining the geometric deviation of the blade control point, interpolation is performed based on the distance of the blade control point in the blade height direction. At the same time, a deformation attenuation coefficient is set so that the deformation gradually decays along the blade height direction, and the offset of the blade control point is evenly spread to the entire blade surface.

[0017] As a further preferred solution: the process of performing distance normalization processing in step S31 is as follows:

[0018] S311: Select the center of the trailing edge of the blade as the starting point p1, assign the relative position S to zero, and assign the adjacent nodes p2, ..p along the blade annular direction in sequence. k , forming the set of leaf control points P: {p1,p2,..p k ,p1};

[0019] S312: Calculate the set of blade control points P: {p1, p2, ..p k ,p1}, the relative distance set D between two adjacent points: {d1,2 ,d 2,3 ,..,d k-1,k ,d k,1}, then the set of leaf control points P:{p1,p2,..p k ,p1} is at a relative distance d from p1 1,2 ,d 1,2 +d 2,3 ,..d 1,2 +d 2,3 +..+d k,1 ;

[0020] S313: d 1,2 ,d 1,2 +d 2,3 ,..d 1,2 +d 2,3 +..+d k,1 At the same time, divide by the maximum value of the set to normalize to [0,1].

[0021] As a further preferred solution: in step S32, a Hicks-Henne type function is arranged based on the superimposed position, and an expression of a blade deformed profile having the same height as the control blade profile is obtained by the Hicks-Henne type function as follows:

[0022]

[0023] Where: x, y, z represent the coordinates of the blade control points, s represents the normalized position of the blade control points, the subscript base represents the initial grid, γ i Represents the coefficient corresponding to the superposition position of the Hicks-Henne type function, by changing γ i The blade profile after the profile change can be obtained by using the value n x ,n y ,n z is the normal unit direction vector of the point.

[0024] As a further preferred solution: in step S33, the process of interpolating the distances between the blade profile control points in the blade height direction is as follows:

[0025] S331: Divide the blade surface into different areas along the height direction according to the blade top, blade root and blade profile at a specified height, and use matrix A p,q Represents the node index of the blade surface, where p represents the height direction of the blade and q represents the circumferential direction of the blade;

[0026] S332: Calculate the blade coordinates within the range of leaf height i and leaf height i+1 using the interpolation method. The interpolation expression is:

[0027]

[0028] Where: p, q represent the row and column numbers of the leaf surface node index respectively, Δ represents the deviation increment of the node profile, Lx represents the normalized coefficient of the distance between leaf height position i and leaf height position i+1 along the height direction, i corresponds to L=0 and i+1 corresponds to L=1;

[0029] S333: Calculate the leaf node offset within the divided area in step S332, and then obtain the leaf node coordinates.

[0030] A further preferred embodiment of the above scheme is as follows: in step S4, the process of evenly spreading the interpolation of the blade profile control point changes to the entire blade surface is as follows:

[0031] S41: offsetting the stacking direction of the blade profile control points at different blade height positions along the circumferential direction;

[0032] S42: Based on the radial basis function interpolation method, a mapping relationship is constructed according to the node coordinates before and after the circumferential offset of the blade control points. At the same time, a deformation attenuation coefficient is set to gradually attenuate the deformation along the blade height. According to the mapping relationship, the node coordinate increment is evenly spread to the entire blade surface. The expression of the node coordinate increment is:

[0033]

[0034] Where: φ represents the radial basis function, ||x j -x i || represents the distance norm from the node to be determined to the deformation control point, w i Indicates the coefficient corresponding to the deformation control point.

[0035] A further preferred embodiment of the above scheme is as follows: in step S5, after obtaining the node coordinate increments of the blade surface, a normal index relationship is constructed based on the orthogonality of the structured grid to diffuse the blade surface grid increments in a direction away from the blade surface, which comprises the following steps:

[0036] S51: Construct the normal index set of the blade surface mesh;

[0037] S52: Based on the constructed normal index set, the offset of the volume mesh is obtained by multiplying the offset of the blade surface mesh by the normal unit vector, so that the deformation is transmitted from the blade surface to the far end.

[0038] Based on the above solution, further, in step S51, the step of constructing the normal index set includes:

[0039] S511: taking the blade surface mesh nodes one by one as the starting point a0, and taking any unit containing a0 as A0;

[0040] S512: Search for the adjacent cell A1 of A0 according to the grid topology, and search for the node closest to a0 in A1 as a1;

[0041] S513: Repeat steps S511 and S512 to establish an ordered normal index relationship from the blade surface to the distal end.

[0042] Based on the above solution, in step S52, in order to ensure that the deformation is concentrated near the blade wall and the fluid domain mesh away from the blade area is not affected, a control coefficient P is introduced when calculating the volume mesh offset. The control coefficient P satisfies the following constraints:

[0043] When the object surface is meshed, P = 1;

[0044] When the grid is remote, P = 0;

[0045] Middle grid, P uniform transition.

[0046] Compared with the prior art, the present invention can produce the following beneficial effects:

[0047] 1. The method of the present invention realizes the coordinated deformation of the flow field and the structural analysis grid based on the orthogonal characteristics of the structural grid, and at the same time satisfies the simulation of the blade profile deviation and the stacking law deviation. It has a good deformation effect on both the local change and the macro adjustment of the blade. By constructing the orthogonal direction node index relationship, the relevant nodes are directly assigned according to the index relationship, and the incremental transfer of the blade surface grid to the surrounding grid is realized at the scale of algebraic operation. Compared with the traditional blade parameterization method, it not only realizes the two deformation modes of blade profile and stacking law at the same time, but also improves the deformation efficiency.

[0048] 2. The present invention utilizes the boundary concept of the topological structure of the fluid domain grid and introduces an O-shaped domain into the solid domain grid. By limiting the deformation domain of the blade structure to the O-shaped domain, the scale of the calculation domain is reduced, thereby improving the overall calculation efficiency.

[0049] 3. The present invention adds a deformation attenuation coefficient to the deformation process of the blade contour and the stacking law, so that the offset increment of the blade control point can gradually decay along the blade height direction until the root and top parts of the blade decay to zero, thereby avoiding reducing the mesh quality of the root and top parts of the blade.

[0050] 4. In the process of diffusing the blade surface grid increment toward the far end along the orthogonal direction of the structural grid, the present invention sets the diffusion attenuation coefficient so that the deformation in the transmission process gradually decays until it decays to zero at the edge of the O-shaped domain, thereby concentrating the deformation on the blade surface area. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the embodiments or the prior art.

[0052] Figure 1 This is a flow chart of a blade parameterization method based on fluid-solid grid collaborative deformation according to the present invention;

[0053] Figure 2 Schematic diagram of the fluid domain and solid domain meshes of an aero-engine axial flow blade of the present invention, wherein: a is the fluid domain mesh, b is the solid domain mesh;

[0054] Figure 3 Schematic diagram of the O-type domain in the fluid domain grid and the solid domain grid of the present invention, wherein: a is the O-type domain in the fluid domain grid, and b is the O-type domain in the solid domain grid;

[0055] Figure 4 Schematic diagram of blade profile control points at different blade height positions of the present invention;

[0056] Figure 5 Schematic diagram of normalized coordinates of blade surfaces at different leaf heights of the present invention, wherein: a is the normalized coordinates of the blade surface at 25% leaf height, b is the normalized coordinates of the blade surface at 50% leaf height, and c is the normalized coordinates of the blade surface at 75% leaf height;

[0057] Figure 6 Schematic diagram of the profile change at different leaf height positions of the present invention, wherein: a is the profile change of a leaf at 25% leaf height, b is the profile change of a leaf at 50% leaf height, and c is the profile change of a leaf at 75% leaf height;

[0058] Figure 7 This is a mesh profile deviation deformation diagram of the blade surface of the present invention, where a is the mesh profile deviation deformation of the fluid domain, and b is the mesh profile deviation deformation of the solid domain;

[0059] Figure 8 This is a schematic diagram of the circumferential offset of the blade profile control point of the present invention;

[0060] Figure 9 : This is a graph showing the deviation and deformation of the grid stacking rule of the blade surface according to the present invention, wherein: a is the deviation and deformation of the grid stacking rule of the fluid domain, and b is the deviation and deformation of the grid stacking rule of the solid domain;

[0061] Figure 10 Schematic diagram of the orthogonality direction of the present invention;

[0062] Figure 11 A schematic diagram of the deformation of the present invention being transmitted from the blade surface to the distal end;

[0063] Figure 12Schematic diagram of the fluid-solid mesh before and after collaborative deformation of the present invention, wherein: a is a diagram of the fluid domain mesh before and after deformation, and b is a diagram of the solid domain mesh before and after deformation. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0065] Reference Figure 1-12 The present invention discloses a blade parameterization method based on fluid-solid grid collaborative deformation, which is mainly aimed at the parameterization of aero-engine axial flow blades. The overall process of the method is as follows: Figure 1 As shown, the following steps are included:

[0066] S1: Construct the initial fluid domain mesh and solid domain mesh adapted to the blade model, and introduce the O-type domain into the solid domain mesh with the help of the topological structure of the fluid domain mesh;

[0067] According to the blade model studied, the initial fluid domain mesh and solid domain mesh required for mesh deformation are established. The topological structure of the fluid domain mesh adopts O4H type, and the meshing software used in the fluid domain is AutoGrid5. With the help of the topological idea of ​​the fluid domain mesh, the O-type domain is introduced into the solid domain mesh, and the deformation domain is limited to the O-type domain. The scale of the calculation domain is reduced to improve the calculation efficiency. The meshing software used in the solid domain is ICEM. The fluid domain mesh and the solid domain mesh are as follows: Figure 2 Middle a, Figure 2 As shown in b, the O-type domain is as follows Figure 3 Middle a, Figure 3 As shown in b.

[0068] S2: The leaf shape point set at different leaf height positions on the blade is used as the leaf shape control point;

[0069] The blades of an aircraft engine can be regarded as countless blade shapes formed by a certain stacking rule. According to the blade shaping principle, blade shape point sets at different positions in the blade height direction are selected as control points, such as Figure 4 As shown, the present invention exemplarily selects three leaf point sets of 25%, 50% and 75% as control points.

[0070] S3: Based on the profile change of the blade, the Hicks-Henne function is used to perform local perturbations on the blade to obtain the geometric deviation of the blade control point, and the geometric deviation is evenly spread to the entire blade surface;

[0071] First, the blade control points are normalized along the blade circumference from the trailing edge. The specific normalization process is as follows:

[0072] The center of the trailing edge of the blade is selected as the starting point p1, the relative position S is assigned to zero, and the adjacent nodes p2, ..p are assigned in sequence along the blade annular direction. k , forming the set of leaf control points P: {p1,p2,..p k ,p1}, calculate the set of blade control points P:{p1,p2,..p k ,p1}, the relative distance set D between two adjacent points: {d 1,2 ,d 2,3 ,..,d k-1,k ,d k,1}, then we can further get the set of blade control points P: {p1,p2,..p k ,p1} is at a relative distance d from p1 1,2 ,d 1,2 +d 2,3 ,..d 1,2 +d 2,3 +..+d k,1 , d 1,2 ,d 1,2 +d 2,3 ,..d 1,2 +d 2,3 +..+d k,1 At the same time, the value is divided by the maximum value of the set and normalized to [0,1]. In the present invention, the set of blade control points is a ring, with p1 as the origin (assigned to zero), and the distance between point p2 and p1 is d 1,2 , the distance between point p3 and p1 is the distance between p3 and p2 plus the distance between p2 and p1, that is, d 1,2 +d 2,3 , and so on, the distance from p1 to p1 is the sum of all relative distances, that is, starting from the trailing edge of the blade, going around a circle and returning to the starting point, and then the distance from each point of the blade control point to p1 (the origin) is divided by the maximum value (that is, the last value in the set D), so that normalization to [0,1] is achieved.

[0073] Then, the superposition position is determined at different positions of the normalized blade, and a Hicks-Henne type function is arranged at the superposition position. The Hicks-Henne type function is used to simulate the geometric deviation of the blade control point. The basis for selecting the superposition position is: (1) uniform distribution along the circumferential direction of the blade; (2) the superposition position should be in the flow sensitive area. Based on the above superposition position selection principle, the present invention selects a total of 11 superposition positions (the first and the last are the same point), which are similar to the superposition positions selected at the corresponding blade height as shown in FIG. Figure 5 In a, such as Figure 5In b, such as Figure 5 As shown in c.

[0074] Arrange the Hicks-Henne type function at the superposition position selected above, f i The expression of (x) is:

[0075]

[0076] in, 0 <x i <1, α and β are shape factors, x represents the relative position S, i represents the three spatial components, and k is the number of control points.

[0077] For the above f i (x) After deformation, the final expression of the deformed blade profile with the same height as the control blade profile is as follows:

[0078]

[0079]

[0080] Where: x, y, z represent the coordinates of the blade control points, s represents the normalized position of the blade control points, the subscript base represents the initial grid, γ i Represents the coefficient corresponding to the superposition position of the Hicks-Henne type function, by changing γ i The blade profile after the profile change can be obtained by using the value n x ,n y ,n z is the normal unit direction vector of the point.

[0081] In the parameterization process, by changing a set of γ i The blade shape after the profile is changed can be obtained by adding the value, such as Figure 6 Middle a- Figure 6 As shown in c, γ i There is no strict regulation on the value of , but this value is very important. If the value is not appropriate, the leading and trailing edge lines of the blade may cross or become uneven. Therefore, in the present invention, γ i Take [-0.00005, 0.00005].

[0082] Finally, after obtaining the geometric deviation of the blade control point, interpolation is performed based on the distance of the blade control point in the blade height direction to evenly spread the offset of the blade control point to the entire blade surface, such as Figure 7 Middle a, Figure 7 To prevent the mesh quality at the blade root and blade top from degrading, a deformation attenuation coefficient is set to gradually attenuate the deformation along the height direction until the deformation at the blade root and blade top is attenuated to zero.

[0083] Specifically, when interpolating based on the distance of the blade control point, the blade surface is divided into different areas along the height direction according to the blade top, blade root and blade profile of the specified height. For example, the present invention selects the three lines of 25%, 50% and 75%, then 0-25% is a zone, 25%-50% is a zone, and so on. If disturbances are made at the blade top and blade root, represented by Δ_high and Δ_low respectively, then for the grid near the blade top, it is greatly affected by the offset of the blade top and less affected by the offset of the blade root. The nodes on the blade surface in the area are affected by the highest offset Δ_high and the lowest offset Δ_low in this area, and the distance will be normalized to [0,1] along the blade top and blade root. Then the blade offset in this area is expressed as Δ_low*L+Δ_high*(1-L); since the blade surface is a quadrilateral grid, the blade surface node index is written in matrix form A p,q , where p represents the number of rows in the matrix, indicating the height direction of the blade, and q represents the number of columns in the matrix, indicating the circumferential direction of the blade. Assuming that the controlled blade profile only affects the adjacent area, the interpolation expression for the blade coordinates within the control blade profile at blade height i and the control blade profile at blade height i+1 is:

[0084]

[0085] Where: p, q represent the number of rows and columns of the blade surface node index respectively, Δ represents the deviation increment of the node profile, L i It represents the normalized coefficient of the distance along the height direction of the control blade profile at blade height i and the control blade profile at blade height i+1, where i corresponds to L=0 and i+1 corresponds to L=1.

[0086] The blade offset within the divided area of ​​the blade surface is then calculated based on the obtained blade coordinates.

[0087] S4: In response to the changes in the overlapping regularity of the blade profile, a mapping relationship is constructed by combining the circumferential offset of the blade profile control points with the radial basis function interpolation method, and the change interpolation is evenly spread across the entire blade surface;

[0088] Assuming that the blade changes only in the circumferential direction when changing the stacking law, without axial adjustment, the stacking direction of the blade control points at different blade height positions is offset circumferentially. The results are as follows: Figure 8 Middle a- Figure 8 As shown in Figure c, according to the node coordinates before and after the circumferential offset of the blade control point, a mapping relationship is constructed by the radial basis function interpolation method, and the node coordinate increment is evenly diffused to the entire blade surface according to the mapping relationship, as shown in Figure c. Figure 9 Middle a, Figure 9 As shown in b, the expression of node coordinate increment is:

[0089]

[0090] Where: φ represents the radial basis function, the present invention selects the Gaussian basis function, ||x j -x i || represents the distance norm from the node to be determined to the deformation control point, w i Indicates the coefficient corresponding to the deformation control point.

[0091] In order to prevent the mesh quality of the blade root and blade top from being reduced, the deformation attenuation coefficient is set to gradually attenuate the deformation along the height direction until the attenuation of the blade root and blade top is zero.

[0092] S5: After obtaining the blade surface node coordinate increments from the above steps, their influence needs to be transferred to the volume mesh. This process is achieved by constructing a normal index relationship based on the orthogonality of the structural mesh, thereby diffusing the blade surface node coordinate increments toward the far end (away from the blade surface) along the orthogonal direction of the structural mesh. By setting the diffusion attenuation coefficient, the deformation gradually decays during the transfer process and decays to zero at the edge of the O-shaped domain.

[0093] In this step, the process of constructing the normal index relationship based on the orthogonality of the structured grid is as follows:

[0094] Construct the normal index set of the blade surface mesh: (a) Take the blade surface mesh point by point as the starting point a0; (a) Take any unit containing a0 as A0, search for the adjacent unit A1 of A0 according to the mesh topology, and search for the node closest to a0 in A1 as a1; (c) Repeat the above steps (a) and (b) to establish an ordered normal index relationship from the blade surface to the far end, such as Figure 10 In this process, when the grid orthogonality is not ideal, relying solely on distance judgment in (b) is not sufficient and requires additional judgment. The principle of the additional judgment is that for any quadrilateral, the sum of its two intersecting sides is always greater than the sum of the distances between its two pairs of sides. Based on this, combined with the above process, the correct orthogonal index node a1 at distance a0 can be determined.

[0095] Based on the constructed normal index set, the offset of the volume mesh is obtained by multiplying the offset of the blade surface mesh by the normal unit vector, so that the deformation is transferred from the blade surface to the distal end. In order to ensure that the deformation is concentrated near the blade wall and the fluid domain mesh far away from the blade area is not affected, a control coefficient P is introduced when calculating the volume mesh offset. The control coefficient P meets the following constraints: for the surface mesh, P = 1; for the distal mesh, P = 0; for the intermediate mesh, P is uniformly transitioned. The result of the deformation transfer from the blade surface to the distal end is shown in the figure. Figure 11 As shown, combined Figure 12 Middle a, Figure 12From the results before and after the fluid-solid mesh collaborative deformation in (b), it can be seen that the method proposed in the present invention has very good consistency in the fluid-solid mesh collaborative deformation.

[0096] It should be noted that the "volume grid", "initial grid" and "structured grid" mentioned in the present invention all include fluid domain grids and solid domain grids. The "volume grid" is used to distinguish the surface grid. The surface grid is the grid of the blade surface layer, and the rest are volume grids.

[0097] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A blade parameterization method based on fluid-solid mesh collaborative deformation, characterized in that: The following steps are involved: S1: Construct the initial fluid domain mesh and solid domain mesh adapted to the blade model, and introduce the O-type domain into the solid domain mesh with the help of the topological structure of the fluid domain mesh; S2: The leaf shape point set at different leaf height positions on the blade is used as the leaf shape control point; S3: Based on the profile change of the blade, the Hicks-Henne function is used to perform local perturbations on the blade to obtain the geometric deviation of the blade control point, and the geometric deviation is evenly spread to the entire blade surface; S4: In response to the changes in the overlapping regularity of the blade profile, a mapping relationship is constructed by combining the circumferential offset of the blade profile control points with the radial basis function interpolation method, and the change interpolation is evenly spread across the entire blade surface; S5: After obtaining the blade surface node coordinate increments from steps S3-S4, the blade surface node coordinate increments are diffused in a direction away from the blade surface along the orthogonal direction of the structural grid. By setting the diffusion attenuation coefficient, the deformation during the diffusion process is attenuated to zero at the edge of the O-shaped domain.

2. The blade parameterization method based on fluid-solid mesh collaborative deformation according to claim 1 is characterized in that: In step S3, the step of diffusing the geometric deviation caused by the change in the blade profile to the entire blade surface includes: S31: normalize the distance of the blade control point from the trailing edge of the blade along the blade; S32: determining superposition positions at different positions of the blade profile after normalization, wherein the superposition positions are located in a flow-sensitive region uniformly distributed along the circumferential direction of the blade profile, and arranging a Hicks-Henne type function at the superposition positions to simulate geometric deviations of blade profile control points using the Hicks-Henne type function; S33: After obtaining the geometric deviation of the blade control point, interpolation is performed based on the distance of the blade control point in the blade height direction. At the same time, a deformation attenuation coefficient is set so that the deformation gradually decays along the blade height direction, and the offset of the blade control point is evenly spread to the entire blade surface.

3. The blade parameterization method based on fluid-solid mesh collaborative deformation according to claim 2 is characterized in that: The process of distance normalization in step S31 is as follows: S311: Select the center of the trailing edge of the blade as the starting point p1, assign the relative position S to zero, and assign the adjacent nodes p2, ..p along the blade annular direction in sequence. k , forming the set of leaf control points P: {p1,p2,..p k ,p1}; S312: Calculate the set of blade control points P: {p1, p2, ..p k ,p1}, the relative distance set D between two adjacent points: {d 1,2 ,d 2,3 ,..,d k-1,k ,d k,1 }, then the set of leaf control points P:{p1,p2,..p k ,p1} is at a relative distance d from p1 1,2 ,d 1,2 +d 2,3 ,..d 1,2 +d 2,3 +..+d k,1 ; S313: d 1,2 ,d 1,2 +d 2,3 ,..d 1,2 +d 2,3 +..+d k,1 At the same time, divide by the maximum value of the set to normalize to [0,1].

4. The blade parameterization method based on fluid-solid mesh collaborative deformation according to claim 3 is characterized in that: In step S32, a Hicks-Henne type function is arranged based on the superposition position, and the expression of the blade deformation profile with the same height as the control blade profile is obtained by the Hicks-Henne type function as follows: Where: x, y, z represent the coordinates of the blade control points, s represents the normalized position of the blade control points, the subscript base represents the initial grid, γ i Represents the coefficient corresponding to the superposition position of the Hicks-Henne type function, by changing γ i The blade profile after the profile change can be obtained by using the value n x ,n y ,n z is the normal unit direction vector of the point.

5. The blade parameterization method based on fluid-solid mesh collaborative deformation according to claim 4 is characterized in that: In step S33, the process of interpolating the distances between the blade profile control points in the blade height direction is as follows: S331: Divide the blade surface into different areas along the height direction according to the blade top, blade root and blade profile at a specified height; S332: Using the interpolation method, calculate the blade coordinates within the control blade profile at blade height i and the control blade profile at blade height i+1. The interpolation expression is: Where: p, q represent the number of rows and columns of the blade surface node index respectively, Δ represents the deviation increment of the node profile, L i represents the normalized coefficient of the controlled blade profile at blade height i and the controlled blade profile at blade height i+1 along the height direction, i corresponds to L=0 and i+1 corresponds to L=1; S333: Calculate the leaf node offset within the divided area in step S332, and then obtain the leaf node coordinates.

6. The blade parameterization method based on fluid-solid mesh collaborative deformation according to claim 5 is characterized in that: In step S4, the process of evenly spreading the interpolation of the blade profile control point changes to the entire blade surface is as follows: S41: offsetting the stacking direction of the blade profile control points at different blade height positions along the circumferential direction; S42: Based on the radial basis function interpolation method, a mapping relationship is constructed according to the node coordinates before and after the circumferential offset of the blade control points. At the same time, a deformation attenuation coefficient is set to gradually attenuate the deformation along the blade height. According to the mapping relationship, the node coordinate increment is evenly spread to the entire blade surface. The expression of the node coordinate increment is: Where: φ represents the radial basis function, ||x j -x i || represents the distance norm from the node to be determined to the deformation control point, w i Indicates the coefficient corresponding to the deformation control point.

7. The blade parameterization method based on fluid-solid mesh collaborative deformation according to claim 6 is characterized in that: In step S5, after obtaining the node coordinate increments of the blade surface, a normal index relationship is constructed based on the orthogonality of the structured grid to diffuse the blade surface grid increments in a direction away from the blade surface. The steps include: S51: Construct the normal index set of the blade surface mesh; S52: Based on the constructed normal index set, the offset of the volume mesh is obtained by multiplying the offset of the blade surface mesh by the normal unit vector, so that the deformation is transmitted from the blade surface to the far end.

8. The blade parameterization method based on fluid-solid mesh collaborative deformation according to claim 7 is characterized in that: In step S51, the steps of constructing the normal index set include: S511: taking the blade surface mesh nodes one by one as the starting point a0, and taking any unit containing a0 as A0; S512: Search for the adjacent cell A1 of A0 according to the grid topology, and search for the node closest to a0 in A1 as a1; S513: Repeat steps S511 and S512 to establish an ordered normal index relationship from the blade surface to the distal end.

9. The blade parameterization method based on fluid-solid mesh collaborative deformation according to claim 7 is characterized in that: In step S52, to ensure that the deformation is concentrated near the blade wall and the fluid domain mesh away from the blade area is not affected, a control coefficient P is introduced when calculating the volume mesh offset. The control coefficient P satisfies the following constraints: When the object surface is meshed, P = 1; When the grid is remote, P = 0; Middle grid, P uniform transition.

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