Shape collaborative optimization design method for engine runner molded surface

Abstract

The invention relates to a shape collaborative optimization design method for an engine runner profile. The method comprises the following steps: discretizing a theoretical inner runner profile and establishing an on-way equivalent stiffness geometric unit; calculating an average displacement vector of the on-way equivalent stiffness geometric unit under multiple working conditions of thermal coupling; calculating a weighted average value of the unit node displacement of each on-way equivalent stiffness geometric unit, obtaining a response node corresponding to the unit node, and obtaining a response profile; evaluating the weighted average error of the response molded surface and the theoretical inner flow channel molded surface, and if the weighted average error is greater than a preset threshold value, carrying out reverse mapping on the unit nodes of the on-way equivalent stiffness geometric unit and constructing a new on-way equivalent stiffness geometric unit, and carrying out a new round of thermal coupling analysis and molded surface fitting iteration of the response nodes; and when the weighted average error meets a preset threshold value, performing profile reconstruction on the reversely mapped unit node corresponding to iteration, and outputting a reconstructed profile as a result of the shape collaborative optimization design.

Description

Technical Field

[0001] The invention relates to the field of aerospace, and in particular to a shape-property collaborative optimization design method for an engine flow channel profile. Background Art

[0002] During the operation of the engine, it undergoes a rapid temperature rise / fall process and complex alternating thermal and mechanical loads, which leads to structural deformation of the engine's internal flow path profile, which in turn causes the geometric characteristic parameters of the internal flow path of the engine under working conditions (such as throat diameter, nozzle outlet parameters, etc.) to deviate from the theoretical design values, ultimately leading to differences in the engine's operating performance parameters (such as specific impulse, expansion ratio, etc.) and the quality of the internal flow field.

[0003] In order to reduce the differences in engine operating performance parameters, make the geometric characteristic parameters of the engine's inner flow channel in the working state consistent with or close to the theoretical design values, and realize the conformal design of the engine's inner flow channel profile; at the same time, in order to meet the shape control requirements of the key geometric positions of the engine and improve the stability of the geometry and function of the engine's inner flow channel structure, it is urgent to propose a more effective shape-property collaborative optimization design method for the engine's flow channel profile to solve the problems faced in engine operation. Summary of the invention

[0004] The purpose of the present invention is to provide a method for collaborative optimization design of the shape of an engine flow channel profile.

[0005] To achieve the above-mentioned object of the invention, the present invention provides a method for the coordinated optimization design of the shape of an engine flow channel profile, comprising: S1. According to the theoretical inner flow channel profile, the theoretical inner flow channel profile is discretized and an equivalent stiffness geometric unit along the flow channel is established; S2. Based on the finite element analysis method and the minimum potential energy principle, the average displacement vector of the equivalent stiffness geometric unit along the process is calculated under multiple thermal-mechanical coupling conditions; S3. Calculating the weighted average of the displacements of the unit nodes of the equivalent stiffness geometric units along the path according to the average displacement vector, obtaining the response nodes corresponding to the unit nodes and performing profile fitting to obtain the response profile corresponding to the theoretical inner flow channel profile; S4. Evaluate the weighted average error between the response surface and the theoretical inner flow channel surface. If the weighted average error is greater than a preset threshold, reversely map the unit nodes of the along-the-way equivalent stiffness geometric unit and construct a new along-the-way equivalent stiffness geometric unit. Based on steps S2 to S4, conduct a new round of thermal-mechanical coupling analysis and surface fitting iteration of the response nodes. Until the weighted average error is less than or equal to the preset threshold, reconstruct the surface of the reverse-mapped unit nodes corresponding to the iteration, and output the reconstructed surface as the result of the shape-property collaborative optimization design.

[0006] According to one aspect of the present invention, it also includes: S5. Based on the obtained reconstructed surface, the along-the-way structural stiffness of the reconstructed surface is regulated and optimized to meet the shape control requirements of preset key geometric positions; wherein, the along-the-way structural stiffness is regulated and optimized by changing the equivalent thickness along the reconstructed surface.

[0007] According to one aspect of the present invention, in step S1, based on the theoretical inner flow channel profile, the step of discretizing the theoretical inner flow channel profile and establishing an equivalent stiffness geometric unit along the path includes: S11. Establishing a profile coordinate system based on the configuration of the theoretical inner flow channel profile; S12. Select the inner flow channel profile on the theoretical inner flow channel profile for discretization to form an along-line equivalent stiffness geometric unit; wherein the along-line equivalent stiffness geometric unit has a plurality of unit nodes, and the plurality of unit nodes include: a unit inner node and a unit outer node; S13. Obtaining the coordinate positions of the plurality of unit nodes based on the profile coordinate system; S14. Based on the principle of structural stiffness equivalence, the internal flow channel of the engine is simplified into a single-layer equivalent wall thickness structure, and the single-layer equivalent wall thickness is assigned to the along-the-way equivalent stiffness geometric unit at the corresponding position, so as to ensure that the equivalent stiffness of the along-the-way equivalent stiffness geometric unit remains consistent with the structural stiffness of the corresponding position along the internal flow channel of the engine; wherein, the single-layer equivalent wall thickness is assigned as the width of the along-the-way equivalent stiffness geometric unit.

[0008] According to one aspect of the present invention, the along-the-path equivalent stiffness geometric unit is an axisymmetric geometric unit.

[0009] According to one aspect of the present invention, in step S2, based on the finite element unit analysis method and the minimum potential energy principle, the step of calculating the average displacement vector of the equivalent stiffness geometric unit along the path under the thermal-mechanical coupling multi-conditions includes: Based on the design parameters of the engine, the displacement of the unit nodes in the equivalent stiffness geometric unit along the path under the action of external loads and the displacement of the unit nodes that are thermally deformed in a thermal environment are calculated respectively; The average displacement vector is obtained based on the unit node displacement under the external load and the unit node displacement caused by thermal deformation.

[0010] According to one aspect of the present invention, in step S2, the unit node displacement under the external load is obtained based on the following steps, which include: Based on the unit analysis method and the minimum potential energy principle in the finite element method, the overall node displacement of the equivalent stiffness geometric unit along the path under the external load is solved, which is expressed as: [K ]{ Q}={ R} [ K ]=

[0011] [ K ] e = rdzdr { R =

[0012] in,[ K ] represents the overall stiffness matrix of the theoretical inner channel profile, { R} represents the column vector of the global node load in the equivalent stiffness geometric unit along the path, F Indicates that the external load is superimposed according to the geometry unit node number, { Q} is the displacement column vector of the global node in the equivalent stiffness geometric unit along the path, and is expressed as: { Q}={ Q 1,…, Q i ,…, Q n}, Q i represents the displacement of the unit node in the equivalent stiffness geometric unit along the path, [ K ] e represents the stiffness matrix of the geometric element with equivalent stiffness along the path, B The function matrix representing the equivalent stiffness geometric unit along the path, D Represents the axisymmetric elastic coefficient matrix of the material, which is obtained based on the axisymmetric unit construction method in the finite element method; Based on the obtained overall node displacement, the unit node displacement of each unit under the external load is obtained respectively and expressed as: Q i =

[0013] in, q i1 and q i2 They represent the inner nodes of the unit, and They represent the outer nodes of the unit respectively.

[0014] According to one aspect of the present invention, in step S2, the unit node displacement caused by thermal deformation is expressed as: Q j = α

[0015] in, α represents the thermal expansion coefficient of the material, T i represents the temperature of the inner node of the element in the equivalent stiffness geometric element along the path, represents the temperature of the outer nodes of the element in the equivalent stiffness geometric element along the path, r i and z i represents the coordinates of the inner nodes of the element, and Represents the coordinates of the outer nodes of the element; In step S2, the average displacement vector is expressed as: =

[0016] in, k represents the number of calculation cases, s j represents the average displacement vector of the inner nodes of the element in the equivalent stiffness geometric element along the path, Represents the average displacement vector of the outer nodes of the element in the equivalent stiffness geometric element along the path.

[0017] According to one aspect of the present invention, in step S3, in the step of calculating the weighted average of the unit node displacements of each along-the-way equivalent stiffness geometric unit according to the average displacement vector, the weighted average is expressed as:

[0018] in,( u j , w j ) represents the coordinates of the inner nodes of the element in the equivalent stiffness geometric element along the path, ( , ) represents the coordinates of the outer nodes of the element in the equivalent stiffness geometry element along the path; In step S3, in the step of obtaining the response nodes corresponding to the unit nodes and performing profile fitting to obtain the response profile corresponding to the theoretical inner flow channel profile, the coordinates of the response nodes of the unit corresponding to the equivalent stiffness geometric unit along the path are expressed as: .

[0019] According to one aspect of the present invention, in step S4, in the step of reverse mapping the unit nodes of the along-path equivalent stiffness geometric unit and constructing a new along-path equivalent stiffness geometric unit, the new along-path equivalent stiffness geometric unit is represented based on the coordinates of the reverse-mapped unit nodes and is:

[0020] According to one aspect of the present invention, in step S5, in the step of regulating and optimizing the structural stiffness along the reconstructed surface by changing the equivalent thickness along the reconstructed surface, a constraint condition is used in which the value of the average displacement vector of the equivalent stiffness geometric unit along the reconstructed surface under multiple thermomechanical coupling conditions is less than a preset value, so as to regulate and optimize the structural stiffness along the reconstructed surface by changing the equivalent thickness along the reconstructed surface.

[0021] According to one scheme of the present invention, by outputting iterative and optimized shape-property collaborative optimization surfaces, the response under multi-operating-condition thermomechanical coupling analysis can be consistent or close to the theoretical inner flow channel surface of the engine, thereby making the geometric characteristic parameters of the inner flow channel of the engine consistent or close to the theoretical design values ​​under the working state, thereby achieving conformal design of the inner flow channel surface of the engine.

[0022] According to one scheme of the present invention, the along-the-line structural stiffness is regulated and optimized by changing the equivalent thickness of the along-the-line geometric units in the response surface designed by collaborative optimization of the shape, thereby meeting the shape control requirements of the key geometric positions of the engine, thereby effectively improving the geometry and functional stability of the flow channels in the engine.

[0023] According to one solution of the present invention, an equivalent stiffness axisymmetric geometric unit is used to perform thermal-mechanical coupling analysis, iterative optimization and surface reconstruction under multiple working conditions on the inner flow channel profile, as well as adjustment and optimization of the structural stiffness along the process. This process can be implemented through programming or finite element simulation, effectively simplifying the iterative and optimization design process.

[0024] According to a solution of the present invention, a reverse mapping method of the average displacement vector is used to construct a new equivalent unit for iteration and optimization of shape coordination, which has the characteristics of small number of iterative optimization times and good convergence, and effectively improves the optimization design efficiency of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a flowchart schematically showing a method for collaborative optimization design of shape according to an embodiment of the present invention; Figure 2 is a flow chart schematically showing a shape-property collaborative optimization design method according to an embodiment of the present invention; Figure 3 is a diagram schematically showing a geometric parameter diagram of an inner flow channel profile according to an embodiment of the present invention; Figure 4 It is a schematic diagram showing the equivalent stiffness geometric unit and unit node parameter diagram along the path according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] When describing the embodiments of the present invention, the orientation or positional relationship expressed by the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or positional relationship shown in the relevant drawings and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0028] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments cannot be described one by one here, but the embodiments of the present invention are not therefore limited to the following embodiments.

[0029] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, according to one embodiment of the present invention, a shape-property collaborative optimization design method of an engine flow channel profile of the present invention includes: S1. According to the theoretical inner flow channel profile, the theoretical inner flow channel profile is discretized and an equivalent stiffness geometric unit along the flow channel is established; S2. Based on the finite element analysis method and the minimum potential energy principle, the average displacement vector of the equivalent stiffness geometric unit along the process under multiple thermal-mechanical coupling conditions is calculated; S3. Calculate the weighted average displacement of the unit node of each equivalent stiffness geometric unit along the process according to the average displacement vector, obtain the response node corresponding to the unit node and perform profile fitting to obtain the response profile corresponding to the theoretical inner flow channel profile; S4. Evaluate the weighted average error between the response surface and the theoretical inner channel surface. If the weighted average error is greater than the preset threshold, reversely map the unit nodes of the along-the-way equivalent stiffness geometric unit and construct a new along-the-way equivalent stiffness geometric unit. Based on steps S2 to S4, conduct a new round of thermal-mechanical coupling analysis and surface fitting iteration of the response node. Until the weighted average error is less than or equal to the preset threshold, reconstruct the surface of the reverse-mapped unit nodes corresponding to the iteration, and output the response reconstructed surface as the result of the shape-property collaborative optimization design.

[0030] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, according to an embodiment of the present invention, in step S1, according to the theoretical inner flow channel profile, the step of discretizing the theoretical inner flow channel profile and establishing the equivalent stiffness geometric unit along the process includes: S11. Establish a profile coordinate system based on the configuration of the theoretical inner flow channel profile; wherein, taking the inner flow channel of the engine as a central axis symmetrical structure as an example, a corresponding rectangular coordinate system can be established based on the central axis of the inner flow channel of the engine, wherein the central axis can be set as z Axis, set in the radial direction of the flow channel in the engine r Axis. Therefore, the geometric parameters of the theoretical inner flow channel profile can be obtained by the cylindrical coordinate parameters of the profile ( r , z ) indicates, see Figure 3 shown.

[0031] S12. Select the inner flow channel profile on the theoretical inner flow channel profile for discretization to form an along-the-way equivalent stiffness geometric unit; wherein, the along-the-way equivalent stiffness geometric unit is an axisymmetric geometric unit, and the along-the-way equivalent stiffness geometric unit has multiple unit nodes, and the multiple unit nodes include: unit inner nodes and unit outer nodes; in this embodiment, the along-the-way equivalent stiffness geometric unit has four unit nodes, wherein two unit inner nodes are provided and two unit outer nodes are provided.

[0032] S13. Based on the profile coordinate system, the coordinate positions of multiple unit nodes are obtained respectively; wherein the inner nodes of the two units can be respectively expressed as ( r i , z i ),( r i+1 , z i+1 ), the two unit outer nodes can be expressed as ( , ),( , ),in, i Indicates the number of the geometric unit with equivalent stiffness along the path, see Figure 3 and Figure 4 shown.

[0033] S14. Based on the principle of structural stiffness equivalence, the flow channel in the engine is simplified into a single-layer equivalent wall thickness structure, and the single-layer equivalent wall thickness is assigned to the equivalent stiffness geometric unit along the corresponding position, so as to ensure that the equivalent stiffness of the equivalent stiffness geometric unit along the flow channel is consistent with the structural stiffness of the corresponding position along the flow channel in the engine; wherein, the single-layer equivalent wall thickness is assigned as the width of the equivalent stiffness geometric unit along the flow channel, and is expressed as ti In this embodiment, based on the structural stiffness equivalence principle, the single-layer or multi-layer structure of the engine inner flow channel along the wall thickness direction can be simplified to a single-layer equivalent wall thickness structure.

[0034] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, according to an embodiment of the present invention, in step S2, based on the finite element unit analysis method and the minimum potential energy principle, the step of calculating the average displacement vector of the equivalent stiffness geometric unit along the process under the thermal-mechanical coupling multi-conditions includes: Based on the design parameters of the engine, the unit node displacement of the unit node in the equivalent stiffness geometric unit under the action of external load and the unit node displacement of thermal deformation in the thermal environment are calculated respectively; in this embodiment, the design parameters of the engine are the temperature and load distribution along the inner flow channel, so that the thermal-mechanical coupling analysis can be carried out to obtain the unit node displacement of the equivalent stiffness geometric unit under the action of external load. Q i and unit node displacement caused by thermal deformation Q j To obtain the overall displacement of the unit nodes in the equivalent stiffness geometric unit along the path.

[0035] In this embodiment, the unit node displacement under the external load is obtained based on the following steps, which include: Based on the unit analysis method and the minimum potential energy principle in the finite element method, the overall node displacement of the axisymmetric problem under external load is solved according to formula (1): [ K ]{ Q}={ R}(1) in,[ K ] represents the overall stiffness matrix of the theoretical inner channel profile (profile), { R} represents the column vector of the global node load in the equivalent stiffness geometric unit along the path, { R = , F The heat, surface force, concentrated force and other loads are superimposed according to the geometry unit node number. Q} is the displacement column vector of the global node in the equivalent stiffness geometric unit along the path, and is expressed as: { Q}={ Q 1,…, Q i ,…, Q n}, Q i It represents the displacement of the unit node in the geometric unit with equivalent stiffness along the path; Furthermore, the overall stiffness matrix [ K ] is formed by superimposing the element stiffness matrix according to the node number and is expressed as: [ K ]= (2) in, It represents the geometric unit stiffness matrix of the equivalent stiffness of the theoretical inner flow channel surface along the way, and it is expressed as: [ K ] e = rdzdr(3) in, B ( r , z ) is the function matrix of the equivalent stiffness geometric unit along the path, D is the axisymmetric elastic coefficient matrix of the material, which can be obtained by referring to the axisymmetric unit construction method in the finite element method.

[0036] Therefore, the process of solving the overall node displacement of the equivalent stiffness geometric unit under the external load can be expressed as: [ K ]{ Q}={ R} [ K ]=

[0037] [ K ] e = rdzdr { R =

[0038] in,[ K ] represents the overall stiffness matrix of the theoretical inner channel profile, { R} represents the column vector of the global node load in the equivalent stiffness geometric unit along the path, F Indicates that the external load is superimposed according to the geometry unit node number, { Q} is the displacement column vector of the global node in the equivalent stiffness geometric unit along the path, and is expressed as: { Q}={ Q 1,…, Q i ,…, Q n}, Q i represents the displacement of the unit node in the equivalent stiffness geometric unit along the path, [ K ] e represents the stiffness matrix of the geometric element with equivalent stiffness along the path, BThe function matrix representing the equivalent stiffness geometric unit along the path, D Represents the axisymmetric elastic coefficient matrix of the material, which is obtained based on the axisymmetric unit construction method in the finite element method; Furthermore, based on the obtained overall node displacement, the unit node displacement of each unit node under the external load is obtained respectively, and expressed as: Q i = (4) in, q i1 and q i2 They represent the inner nodes of the unit, and They represent the outer nodes of the unit respectively.

[0039] In this embodiment, the unit node displacement caused by thermal deformation is expressed as: Q j = α (5) in, α represents the thermal expansion coefficient of the material, T i represents the temperature of the inner node of the element in the equivalent stiffness geometric element along the path, represents the temperature of the outer nodes of the element in the equivalent stiffness geometric element along the path, r i and z i represents the coordinates of the inner nodes of the element, and Represents the coordinates of the outer nodes of the element; The average displacement vector is obtained based on the unit node displacement under the external load and the unit node displacement caused by thermal deformation. In this embodiment, the average displacement vector under different working conditions can be obtained based on the unit node displacement under the external load and the unit node displacement caused by thermal deformation, and the average displacement vector is expressed as: = (6) in, k represents the number of calculation cases, s j represents the average displacement vector of the inner nodes of the element in the equivalent stiffness geometric element along the path, Represents the average displacement vector of the outer nodes of the element in the equivalent stiffness geometric element along the path.

[0040] like Figure 1As shown, according to an embodiment of the present invention, in step S3, in the step of calculating the weighted average of the unit node displacements of each along-path equivalent stiffness geometric unit according to the average displacement vector, the weighted average is expressed as:

[0041] in,( u j , w j ) represents the coordinates of the inner nodes of the element in the equivalent stiffness geometric element along the path, ( , ) represents the coordinates of the outer nodes of the element in the equivalent stiffness geometry element along the path; Further, in step S3, in the step of obtaining the response nodes corresponding to the unit nodes and performing profile fitting to obtain the response profile corresponding to the theoretical inner flow channel profile, the coordinates of the response nodes of the unit corresponding to the equivalent stiffness geometric unit along the response profile are expressed as: .

[0042] Therefore, the response surface (profile) of the inner flow channel is obtained by fitting the response nodes, as shown in Figure 3 shown.

[0043] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, according to one embodiment of the present invention, in step S4, in the step of evaluating the weighted average error between the response profile and the theoretical inner flow channel profile, if the weighted average error is less than or equal to a preset threshold, the theoretical inner flow channel profile is output as a result of the shape-property collaborative optimization design.

[0044] According to an embodiment of the present invention, in step S4, in the step of reverse mapping the unit nodes of the along-path equivalent stiffness geometric unit and constructing a new along-path equivalent stiffness geometric unit, the new along-path equivalent stiffness geometric unit is represented based on the coordinates of the reversely mapped unit nodes and is:

[0045] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, according to one embodiment of the present invention, a method for collaborative optimization design of the shape of an engine flow channel profile of the present invention further includes: S5. Based on the obtained reconstructed surface, the structural stiffness along the reconstructed surface is regulated and optimized to meet the shape control requirements of the preset key geometric positions; wherein, the structural stiffness along the reconstructed surface is regulated and optimized by changing the equivalent thickness along the reconstructed surface. Figure 3 As shown in FIG. 1 , the key positions of the flow channel profile in the engine include: key position A, key position B, and key position C. Then, the value of the average displacement vector of the equivalent stiffness geometric unit along the process under the thermomechanical coupling multi-working conditions is taken as a constraint condition to change the equivalent thickness along the process of the reconstructed profile to regulate and optimize its structural stiffness along the process. Specifically, the equivalent thickness can be adjusted based on formulas (1) to (6) in the above steps. t i The optimization setting is to achieve the equivalent stiffness along the geometric unit stiffness matrix [ K ] e Optimization adjustment.

[0046] The above contents are merely examples of specific solutions of the present invention. For devices and structures not described in detail therein, it should be understood that they can be implemented by adopting general devices and general methods available in the art.

[0047] The above is only one solution of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for collaborative optimization design of the shape of an engine flow channel profile, characterized in that: include: S1. According to the theoretical inner flow channel profile, the theoretical inner flow channel profile is discretized and an equivalent stiffness geometric unit along the flow channel is established; S2. Based on the finite element analysis method and the minimum potential energy principle, the average displacement vector of the equivalent stiffness geometric unit along the process is calculated under multiple thermal-mechanical coupling conditions; S3. Calculating the weighted average of the displacements of the unit nodes of the equivalent stiffness geometric units along the path according to the average displacement vector, obtaining the response nodes corresponding to the unit nodes and performing profile fitting to obtain the response profile corresponding to the theoretical inner flow channel profile; S4. Evaluate the weighted average error between the response surface and the theoretical inner flow channel surface. If the weighted average error is greater than a preset threshold, reversely map the unit nodes of the along-the-way equivalent stiffness geometric unit and construct a new along-the-way equivalent stiffness geometric unit. Based on steps S2 to S4, conduct a new round of thermal-mechanical coupling analysis and surface fitting iteration of the response nodes. Until the weighted average error is less than or equal to the preset threshold, reconstruct the surface of the reverse-mapped unit nodes corresponding to the iteration, and output the reconstructed surface as the result of the shape-property collaborative optimization design.

2. The shape-property collaborative optimization design method according to claim 1, characterized in that: Also includes: S5. Based on the obtained reconstructed surface, the along-the-way structural stiffness of the reconstructed surface is regulated and optimized to meet the shape control requirements of preset key geometric positions; wherein, the along-the-way structural stiffness is regulated and optimized by changing the equivalent thickness along the reconstructed surface.

3. The shape-property collaborative optimization design method according to claim 2, characterized in that: In step S1, according to the theoretical inner flow channel profile, the step of discretizing the theoretical inner flow channel profile and establishing an equivalent stiffness geometric unit along the path includes: S11. Establishing a profile coordinate system based on the configuration of the theoretical inner flow channel profile; S12. Select the inner flow channel profile on the theoretical inner flow channel profile for discretization to form an along-line equivalent stiffness geometric unit; wherein the along-line equivalent stiffness geometric unit has a plurality of unit nodes, and the plurality of unit nodes include: a unit inner node and a unit outer node; S13. Obtaining the coordinate positions of the plurality of unit nodes based on the profile coordinate system; S14. Based on the principle of structural stiffness equivalence, the internal flow channel of the engine is simplified into a single-layer equivalent wall thickness structure, and the single-layer equivalent wall thickness is assigned to the along-the-way equivalent stiffness geometric unit at the corresponding position, so as to ensure that the equivalent stiffness of the along-the-way equivalent stiffness geometric unit remains consistent with the structural stiffness of the corresponding position along the internal flow channel of the engine; wherein, the single-layer equivalent wall thickness is assigned as the width of the along-the-way equivalent stiffness geometric unit.

4. The shape-property collaborative optimization design method according to claim 3, characterized in that: The along-the-path equivalent stiffness geometric unit is an axisymmetric geometric unit.

5. The shape-property collaborative optimization design method according to claim 4, characterized in that: In step S2, based on the finite element unit analysis method and the minimum potential energy principle, the step of calculating the average displacement vector of the equivalent stiffness geometric unit along the path under the thermal-mechanical coupling multi-conditions includes: Based on the design parameters of the engine, the displacement of the unit nodes in the equivalent stiffness geometric unit along the path under the action of external loads and the displacement of the unit nodes that are thermally deformed in a thermal environment are calculated respectively; The average displacement vector is obtained based on the unit node displacement under the external load and the unit node displacement caused by thermal deformation.

6. The shape-property collaborative optimization design method according to claim 5, characterized in that: In step S2, the unit node displacement under the external load is obtained based on the following steps, which include: Based on the unit analysis method and the minimum potential energy principle in the finite element method, the overall node displacement of the equivalent stiffness geometric unit along the path under the external load is solved, which is expressed as: [ K ]{ Q}={ R} [ K ]= [ K ] e = rddr { R}= in,[ K ] represents the overall stiffness matrix of the theoretical inner channel profile, { R } represents the column vector of the global node load in the equivalent stiffness geometric unit along the path, F Indicates that the external load is superimposed according to the geometry unit node number, { Q } is the displacement column vector of the global node in the equivalent stiffness geometric unit along the path, and is expressed as: { Q }={ Q 1,…, Q i ,…, Q n }, Q i represents the displacement of the unit node in the equivalent stiffness geometric unit along the path, [ K ] e represents the stiffness matrix of the geometric element with equivalent stiffness along the path, B The function matrix representing the equivalent stiffness geometric unit along the path, D Represents the axisymmetric elastic coefficient matrix of the material, which is obtained based on the axisymmetric unit construction method in the finite element method; Based on the obtained overall node displacement, the unit node displacement of each unit under the external load is obtained respectively and expressed as: Q i = in, q i1 and q i2 They represent the inner nodes of the unit, and They represent the outer nodes of the unit respectively.

7. The shape-property collaborative optimization design method according to claim 6, characterized in that: In step S2, the unit node displacement caused by thermal deformation is expressed as: Q j = α in, α represents the thermal expansion coefficient of the material, T i represents the temperature of the inner node of the element in the equivalent stiffness geometric element along the path, represents the temperature of the outer nodes of the element in the equivalent stiffness geometric element along the path, r i and z i represents the coordinates of the inner nodes of the element, and Represents the coordinates of the outer nodes of the element; In step S2, the average displacement vector is expressed as: = in, k represents the number of calculation cases, s j represents the average displacement vector of the inner nodes of the element in the equivalent stiffness geometric element along the path, Represents the average displacement vector of the outer nodes of the element in the equivalent stiffness geometric element along the path.

8. The shape-property collaborative optimization design method according to claim 7, characterized in that: In step S3, in the step of calculating the weighted average of the unit node displacements of each along-the-way equivalent stiffness geometric unit according to the average displacement vector, the weighted average is expressed as: in,( u j , w j ) represents the coordinates of the inner nodes of the element in the equivalent stiffness geometric element along the path, ( , ) represents the coordinates of the outer nodes of the element in the equivalent stiffness geometry element along the path; In step S3, in the step of obtaining the response nodes corresponding to the unit nodes and performing profile fitting to obtain the response profile corresponding to the theoretical inner flow channel profile, the coordinates of the response nodes of the unit corresponding to the equivalent stiffness geometric unit along the path are expressed as: 。 9. The shape-property collaborative optimization design method according to claim 8, characterized in that: In step S4, in the step of reverse mapping the unit nodes of the along-path equivalent stiffness geometric unit and constructing a new along-path equivalent stiffness geometric unit, the new along-path equivalent stiffness geometric unit is represented based on the coordinates of the reverse-mapped unit nodes and is: 。 10. The shape-property collaborative optimization design method according to claim 9, characterized in that: In step S5, in the step of regulating and optimizing the structural stiffness along the reconstructed surface by changing the equivalent thickness along the reconstructed surface, the value of the average displacement vector of the equivalent stiffness geometric unit along the reconstructed surface under multiple thermal-mechanical coupling conditions is taken as a constraint condition to be less than a preset value, so as to regulate and optimize the structural stiffness along the reconstructed surface by changing the equivalent thickness along the reconstructed surface.

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