Sealing performance optimization analysis method for regenerative cooling metal sealing flange structure

Abstract

The invention relates to a liquid rocket engine, and provides a regenerative cooling metal sealing flange structure sealing performance optimization analysis method in order to solve the problems that an existing finite element analysis model is too large, the calculation cost is high, and a reliable structure optimization scheme cannot be provided. The temperature distribution before and after simplification is consistent; screening factors influencing the opening amount of the regenerative cooling metal sealing flange, and obtaining an initial regenerative cooling metal sealing flange structure meeting the sealing performance; applying a pressure load and a temperature load to the initial regenerative cooling metal sealing flange structure meeting the sealing performance according to the service condition of the regenerative cooling metal sealing flange structure, calculating an obtained finite element temperature field result and an obtained finite element pressure field result, and extracting related calculation data of the regenerative cooling metal sealing flange structure in a service state; the sealing performance of the initial regenerative cooling metal sealing flange structure is evaluated and analyzed in detail, and optimization analysis of the sealing performance of the regenerative cooling metal sealing flange structure is completed.

Description

Technical Field

[0001] The invention relates to a sealing system of a liquid rocket engine, and in particular to a sealing optimization analysis method for a regenerative cooling metal sealing flange structure. Background Art

[0002] Metal sealing flange structures are widely used in pressurized pipeline systems of liquid rocket engines, and sealing leakage is the main failure mode of metal sealing flange structures in high-temperature gas circuits. In order to reduce the failure risk of metal sealing flange structures, regenerative cooling metal sealing flange structures are often used in high-temperature gas circuits to reduce the service temperature of flange sealing fastener systems, and the risk of sealing failure is reduced by controlling the thermal separation caused by high temperature and reducing the stiffness of materials; however, this structure will increase the considerations for the rationality of the structural design of the sealing flange fastener system, making the structural design environment complicated. If there is an unreasonable distribution of cooling channels in the design, the thermal deformation of the upper and lower flanges will be inconsistent, which will have an adverse effect on the metal sealing flange structure and increase the risk of sealing failure.

[0003] During the service of liquid rocket engines, the regenerative cooling metal sealing flange structure is subjected to complex forces and thermal coupling loads such as bolt preload, pressure loads of gas and cooling medium, and non-uniform hot and cold temperature fields, which makes its sealing performance correlated with the bolt preload, pressure load distribution, and the stiffness of the flange joint itself. Its sealing performance will also be significantly affected by thermal deformation. The coupling effect of the above-mentioned thermal coupling loads further increases the difficulty of designing the regenerative cooling metal sealing flange structure, and cannot effectively guarantee the sealing, reliability and stability of the structure.

[0004] At present, there is no complete and reliable analysis method for the sealing, reliability and stability of the regenerative cooling metal sealing flange structure design, which cannot provide data support for the optimized structural design; in order to evaluate the sealing, reliability and stability of the regenerative cooling metal sealing flange structure design, it is necessary to simulate the mechanical and thermal coupling behavior of the seal-flange-fastener structure under service, identify the influence of mechanical load and temperature load on the sealing performance, establish a sealing evaluation method, and then formulate a structural optimization analysis process. The simple analysis method currently used is to directly evaluate the structural design through finite element software, but the pressure field and complex non-uniform temperature field generated by hot gas and cooling medium need to be considered in the finite element analysis. However, the geometric shape of the cooling channel structure is very complex. Directly establishing the cooling channel model will lead to an analysis model that is too large in scale and extremely high in computational cost, resulting in too much analysis data, increasing the design difficulty of the optimization scheme, and affecting the reliability and effectiveness of the structural optimization scheme design. Therefore, it is very necessary to establish an effective design evaluation method. Summary of the invention

[0005] The purpose of the present invention is to solve the problems that when the structural design of the regenerative cooling metal sealing flange is directly evaluated by the finite element analysis method, the analysis model is too large, the calculation cost is extremely high, there is too much analysis data, and a reliable structural optimization solution cannot be provided. A regenerative cooling metal sealing flange structural sealing optimization analysis method is proposed.

[0006] To achieve the above objectives, the technical solution proposed by the present invention is:

[0007] A method for optimizing the sealing performance of a regenerative cooling metal sealing flange structure is characterized in that it comprises the following steps:

[0008] S1. In the finite element software, a three-dimensional geometric model of the regenerative cooling metal sealing flange structure to be subjected to sealing optimization analysis is established, and performance parameters related to the temperature change of the regenerative cooling metal sealing flange structure material are imported; the cooling channel in the regenerative cooling metal sealing flange structure is simplified by the geometric trimming method, and the temperature distribution of the simplified metal sealing flange structure is made consistent with the actual temperature distribution of the metal sealing flange structure before simplification, so as to obtain a simplified regenerative cooling metal sealing flange structure model;

[0009] S2. In the simplified regenerative cooling metal sealing flange structure model, identify the factors that affect the opening amount of the regenerative cooling metal sealing flange, obtain the influence ratio of the temperature load and the pressure load on the sealing performance of the regenerative cooling metal sealing flange structure, and judge whether the simplified regenerative cooling metal sealing flange structure strength and stiffness meet the preset indicators; if so, obtain the initial regenerative cooling metal sealing flange structure that meets the sealing performance, and then execute step S3; if not, return to step S1, and strengthen the regenerative cooling metal sealing flange structure until it meets the preset indicators;

[0010] S3. Establish a three-dimensional geometric model of the initial regenerative cooling metal sealing flange structure, and then apply pressure load and temperature load to the initial regenerative cooling metal sealing flange structure that meets the sealing performance according to the service conditions of the regenerative cooling metal sealing flange structure, submit the calculation and obtain the strength and stiffness result data of the initial regenerative cooling metal sealing flange structure that meets the sealing performance under the service state, and extract the calculation data related to the sealing performance under the service state, that is, the opening amount and the residual compression amount;

[0011] S4. Conduct a detailed evaluation and analysis on the sealing performance of the initial regenerative cooling metal sealing flange structure, establish a detailed analysis model for the sealing performance of the metal sealing flange structure, use the relevant calculation data extracted in step S3 as input to simulate the actual service conditions of the initial regenerative cooling metal sealing flange structure, obtain the sealing performance parameters of the initial regenerative cooling metal sealing flange structure under the actual service state, and combine the strength and stiffness evaluation data extracted in step S3 to complete the optimization analysis of the sealing performance of the regenerative cooling metal sealing flange structure.

[0012] Furthermore, step S1 is specifically as follows:

[0013] S1.1. In the finite element software, establish a three-dimensional geometric model of the regenerative cooling metal sealing flange structure for which sealing optimization analysis is to be performed;

[0014] S1.2. Import the performance parameters related to the temperature change of the regenerative cooling metal sealing flange structure material; S1.3. Simplify the geometric mutation area in the cooling channel of the regenerative cooling metal sealing flange structure by geometric trimming method;

[0015] S1.4. In the simplified finite element model, establish a temperature load analysis model and set boundary constraints and temperature loads;

[0016] S1.5. Calculate the temperature distribution of the metal sealing flange structure before simplification and the temperature distribution of the metal sealing flange structure after simplification through the temperature load analysis model, and compare and judge whether the temperature distributions of the two are consistent;

[0017] If yes, proceed to step S2; if no, return to step S1.3, modify the geometric trimming method to simplify the cooling channel again until the temperature distribution of the two is consistent.

[0018] Furthermore, in step S1.1, the three-dimensional geometric model of the regenerative cooling metal sealing flange structure does not include a sealing ring structure of the metal sealing flange.

[0019] Furthermore, in step S1.2, the performance parameters related to temperature changes include elastic modulus, Poisson's ratio, yield strength, tensile strength, elongation, thermal expansion coefficient and thermal conductivity.

[0020] Furthermore, step S2 is specifically as follows:

[0021] S2.1. In the simplified regenerative cooling metal sealing flange structure model, a mechanical load analysis model and a temperature load analysis model are established respectively, and the simplified regenerative cooling metal sealing flange structure three-dimensional geometric model is divided into finite element meshes;

[0022] S2.2. Set the displacement boundary according to the actual stiffness distribution and force transmission characteristics of the regenerative cooling metal sealing flange structure, submit the calculation and analysis of the mechanical load analysis model and the temperature load analysis model respectively, and obtain the opening amount of the regenerative cooling metal sealing flange under the pressure load and temperature load respectively;

[0023] S2.3. Compare and analyze the effects of mechanical load and temperature load on the opening of the regenerative cooling metal sealing flange, and then obtain the influence ratio of pressure load and temperature load on the sealing performance of the regenerative cooling metal sealing flange structure, and determine the optimization direction of the regenerative cooling metal sealing flange structure;

[0024] S2.4. Determine whether the strength and stiffness of the simplified regenerative cooling metal sealing flange structure meet the preset indicators; if so, obtain an initial regenerative cooling metal sealing flange structure that meets the sealing performance, and then execute step S3; if it does not meet the preset indicators, return to step S1, and use the optimization direction determined in step S2.3 to strengthen the regenerative cooling metal sealing flange structure until it meets the preset indicators.

[0025] Furthermore, step S3 is specifically as follows:

[0026] S3.1. Establish a three-dimensional geometric model of the initial regenerative cooling metal sealing flange structure that meets the sealing performance in finite element software;

[0027] S3.2. Performance parameters of the imported and regenerated cooling metal sealing flange structural materials related to temperature changes;

[0028] S3.3. According to the actual service conditions of the regenerative cooling metal sealing flange structure, the initial regenerative cooling metal sealing flange structure that meets the sealing performance is subjected to contact relationship and boundary conditions in the temperature load analysis model, and meshing is performed to obtain a temperature field calculation model; displacement boundaries and periodic symmetry boundaries are set in the mechanical load analysis model, and meshing is performed to obtain a mechanical load calculation model;

[0029] S3.4. Apply temperature load to the temperature field calculation model of the initial regenerative cooling metal sealing flange structure according to the structural temperature distribution calculated by fluid heat transfer, and submit the calculation to obtain the finite element temperature field results;

[0030] S3.5. Apply pressure load to the mechanical load calculation model according to the actual service conditions of the regenerative cooling metal sealing flange structure, import the finite element temperature field results in step S3.4, and submit the calculation to obtain the finite element results under the actual service conditions;

[0031] S3.6. According to the finite element results in step S3.5, the strength and stiffness evaluation data of the initial regenerative cooling metal sealing flange structure that meets the sealing performance under the service state are obtained, and the opening amount and residual compression amount of the initial regenerative cooling metal sealing flange structure under the actual service condition are extracted. ;

[0032] Furthermore, step S4 is specifically as follows:

[0033] S4.1. Establish a sealing performance evaluation model for the initial regenerative cooling metal sealing flange structure;

[0034] S4.2. Performance parameters of the imported and regenerated cooling metal sealing flange structural materials related to temperature changes;

[0035] S4.3. According to the structural relationship of the actual service condition of the regenerative cooling metal sealing flange structure, the contact relationship and boundary conditions are applied in the sealing performance evaluation model, and the mesh is divided;

[0036] S4.4, using the relevant calculation data extracted in step S3 as input, applying pressure load and temperature load to the sealing performance evaluation model to simulate the actual service condition of the initial regenerative cooling metal sealing flange structure;

[0037] S4.5. Extract the sealing performance parameters of the initial regenerative cooling metal sealing flange structure from the calculation results of the sealing performance evaluation model, and combine them with the phase strength and stiffness evaluation data extracted in step S3 to complete a detailed evaluation of the sealing performance of the regenerative cooling metal sealing flange structure.

[0038] Beneficial effects of the present invention:

[0039] [1] The sealing optimization analysis method for the regenerative cooling metal sealing flange structure of the present invention is concise and easy to operate. By simplifying the geometric mutation area in the cooling channel structure, the difficulty of structural modeling is greatly reduced, the model scale can be effectively reduced, and the analysis efficiency can be improved.

[0040] [2] In the present invention, by identifying the factors that affect the opening amount of the regenerative cooling metal sealing flange, the influence ratio of the pressure load and the temperature load on the sealing performance of the regenerative cooling metal sealing flange structure is obtained respectively, which can effectively clarify the direction of structural improvement and improve the efficiency of design iteration.

[0041] [3] In the present invention, a method of establishing multiple analysis models in finite element software is adopted. The multiple analysis models analyze and evaluate the sealing performance of the regenerative cooling metal sealing flange structure step by step from a rough model to a detailed model, which can completely and effectively evaluate and optimize the sealing performance of the regenerative cooling metal sealing flange structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A simplified schematic diagram of a cooling channel in a regenerative cooling metal sealing flange structure optimized and analyzed in an embodiment of the present invention;

[0043] Figure 2 This is a schematic diagram of the extraction position of the separation amount of the upper and lower flanges of the regenerative cooling metal sealing flange structure for optimization analysis in step S2 of an embodiment of the present invention;

[0044] Figure 3 The three-dimensional geometric model of the initial regenerative cooling metal sealing flange structure established for the regenerative cooling metal sealing flange structure in step S3 of the embodiment of the present invention;

[0045] Figure 4 This is a schematic diagram of meshing the sealing performance evaluation model of the regenerative cooling metal sealing flange structure in step S4 of an embodiment of the present invention. DETAILED DESCRIPTION

[0046] A method for optimizing the sealing performance of a regenerative cooling metal sealing flange structure comprises the following steps:

[0047] S1. A simplified finite element model is established in the finite element software ABAQUS. The regenerative cooling metal sealing flange structure is reasonably simplified, which can effectively reduce the modeling difficulty of the regenerative cooling metal sealing flange structure. For the complex cooling channels in the regenerative cooling metal sealing flange structure, the cooling channels are simplified by means of circumferential splitting and sweep cutting without changing the channel cooling effect and the overall stiffness of the structure. A three-dimensional finite element model is used to perform steady-state heat conduction calculation on the simplified regenerative cooling metal sealing flange structure to obtain the temperature distribution in the simplified cooling channel. The actual temperature distribution in the cooling channel before simplification obtained by fluid heat transfer calculation is compared to make the actual temperature distribution in the cooling channel before simplification consistent with the temperature distribution in the simplified cooling channel. The specific steps are as follows:

[0048] S1.1. Perform necessary geometric cleaning on the three-dimensional geometric model of the regenerative cooling metal sealing flange structure to facilitate meshing, ignore the sealing ring structure in the regenerative cooling metal sealing flange structure, and then import the three-dimensional geometric model into ABAQUS for finite element modeling;

[0049] S1.2. Input the elastic modulus, Poisson's ratio, yield strength, tensile strength and elongation, thermal expansion coefficient and thermal conductivity of the regenerative cooling metal sealing flange and fastener materials as they change with temperature;

[0050] S1.3, if Figure 1 As shown in the figure, the geometric area containing the cooling channel is separated by cutting along the circumferential direction, and the complex geometric mutation area in the cooling channel is simplified by the sweep function;

[0051] S1.4. Use the second-order tetrahedral heat transfer entity element and hexahedral linear heat transfer entity element in ABAQUS to perform finite element meshing on the three-dimensional geometric model of the regenerative cooling metal sealing flange structure;

[0052] S1.5. In the regenerative cooling metal sealing flange structure, contact pairs are set between the limiting surfaces of the upper flange and the lower flange, between the bolts and the bolt hole wall, between the bolts and the gaskets, and between the gaskets and the upper flange. The contact pair discretization method is selected as "surface-to-surface".

[0053] S1.6. Apply thermal boundaries to the finite element model according to the structural wall temperature distribution calculated by fluid heat transfer, and establish a heat transfer analysis step: obtain the temperature field of the simplified regenerative cooling metal sealing flange structure through steady-state heat conduction. If the actual temperature distribution in the cooling channel before simplification is consistent with the temperature distribution in the cooling channel after simplification, proceed to step S2; if the actual temperature distribution in the cooling channel before simplification is inconsistent with the temperature distribution in the cooling channel after simplification, return to step S1.3, modify the geometric trimming method and simplify the cooling channel again until the actual temperature distribution in the cooling channel before simplification is consistent with the temperature distribution in the cooling channel after simplification.

[0054] S2. Identify the factors that affect the opening amount of the regenerative cooling metal sealing flange, obtain the key parameters such as the opening amount and residual compression amount of the metal sealing flange structure under the action of temperature load and pressure load, and clarify the direction of structural improvement and optimization: Use a three-dimensional model to establish a pressure load analysis model and a temperature load analysis model respectively. By applying pressure load and temperature load to the two models respectively, the influence ratio of pressure load and temperature load on the structural sealing performance is obtained, thereby confirming the optimization direction of the structure. When the sum of the opening amounts of the flanges in the two analysis models meets the preset indicators, the initial regenerative cooling metal sealing flange structure that meets the sealing performance is obtained; the specific steps are as follows:

[0055] S2.1. Based on the simplified finite element model obtained in step S1, a mechanical load analysis model and a temperature load analysis model are established respectively, and the finite element meshing of the three-dimensional geometric model of the regenerative cooling flange structure is performed using second-order tetrahedral units and hexahedral linear reduced integration units.

[0056] S2.2. The displacement boundary is set according to the stiffness distribution and force transmission characteristics of the actual system where the regenerative cooling metal sealing flange structure is located. The calculation process is divided into two static analysis steps: the first step is to apply a preload to the bolts in the two analysis models; the second step is to apply a pressure load to the mechanical load analysis model and to apply the temperature field obtained in step 106 to the temperature load analysis model.

[0057] S2.3. After the analysis and calculation are completed, the stress, strain and deformation of the flange and bolts at the end of the first step of the calculation in step S2.2 are output, and the distance between the upper and lower flanges near the inner wall of the sealing groove is extracted, such as Figure 2 As shown; the stress, strain and deformation of the flange and bolt at the end of the second step are output respectively, the distance between the upper and lower flanges near the inner wall of the sealing groove is extracted, and the flange opening under the pressure load and temperature load are obtained respectively.

[0058] S2.4. Compare the opening amounts caused by pressure load and temperature load to determine the optimization and improvement direction of the structure. If the flange opening amount is too large under pressure load, it is improved by increasing the flange stiffness. If the flange opening amount is too large under temperature load, the temperature distribution of the structure is improved by adjusting the cooling channel distribution. After the structure is improved, repeat the above steps until the sum of the separation amounts of the structure under pressure load and temperature load meets the preset indicators.

[0059] S3. Evaluate the strength and stiffness of the initial regenerative cooling metal sealing flange structure that meets the sealing performance: Use a three-dimensional periodic symmetric model to apply pressure loads and temperature loads to the structure according to the service conditions of the regenerative cooling metal sealing flange structure, and obtain the strength and stiffness of the fasteners, flanges, and sealing rings under the service state. At the same time, obtain the compression, opening, and residual compression of the flange structure. The specific steps are as follows:

[0060] S3.1. Cut out a periodic symmetrical sector containing a bolt from the finite element model that meets the analysis conditions of step S2, and simultaneously establish a corresponding sealing ring structure;

[0061] S3.2. Input the elastic modulus, Poisson's ratio, yield strength, tensile strength, elongation after fracture, thermal expansion coefficient, and thermal conductivity of the sealing ring base material, flange material, and fastener material as they change with temperature;

[0062] S3.3. Set contact pairs between the sealing ring and the sealing ring groove of the flange, between the upper flange and the lower flange limit surface, between the bolt and the bolt hole wall, between the bolt and the gasket, and between the gasket and the upper flange. In the sealing ring-upper / lower flange ring groove contact pair, the sealing ring is the secondary contact surface, the flange ring groove is the primary contact surface, and the discrete method is "nod-to-surface"; the discrete method for the remaining contact pairs is "surface-to-surface";

[0063] S3.4. Use second-order tetrahedral heat transfer entity elements and hexahedral linear heat transfer entity elements to perform finite element meshing on the three-dimensional geometric model of the regenerative cooling metal flange, and locally refine the finite element meshes near the sealing ring and flange ring groove;

[0064] S3.5. Apply thermal boundaries to the finite element model according to the structural temperature distribution calculated by fluid heat transfer, apply periodic symmetric boundaries, and establish a heat transfer analysis step: obtain the temperature field of the sector model through steady-state heat conduction;

[0065] S3.6. Change the unit type in step S3.4 to a second-order tetrahedral unit and a hexahedral linear reduced-integral unit, set the displacement boundary and the periodic symmetric boundary according to the stiffness distribution and force transmission characteristics of the actual system in which the structure is located, and the calculation process is divided into three static analysis steps: the first step is to apply a preload to the bolt; the second step is to apply a mechanical load to the structure; the third step is to apply a temperature load to the structure by reading the temperature field in step 305;

[0066] S3.7. After submitting the analysis and calculation, first output the distance between the upper and lower sealing lips in the sealing ring in the initial state, extract the distance between the upper and lower sealing lips of the sealing ring at the end of the first step of calculation, and determine the compression amount of the sealing ring; output the stress, strain, deformation and temperature distribution of the flange, bolt and sealing ring at the end of the third step, and extract the distance between the upper and lower sealing lips of the sealing ring to obtain the opening amount and residual compression amount of the regenerative cooling metal sealing flange structure under actual working conditions.

[0067] S4. Detailed analysis of the sealing performance of the regenerative cooling metal sealing flange structure that meets the strength and stiffness requirements: establish a two-dimensional axisymmetric model, ignore the fastener structure, establish a specific sealing ring structure, and build a coating at the sealing lip; use the compression amount in step S3 as the initial input, apply the load through displacement control to ensure that the remaining compression amount in the two-dimensional model is consistent with the remaining compression amount in step S3, and apply temperature loads to the sealing ring and coating in the model to simulate the state of the sealing ring structure under service conditions. Finally, extract the contact pressure and contact width at the sealing lip position in the structure, draw the contact pressure and contact width change curves, and complete the detailed analysis of the sealing performance of the structure;

[0068] S4.1. Extract the sealing ring cross section, build the soft metal coating, and establish a two-dimensional axisymmetric geometric model of the sealing ring compressed by a pair of rigid surfaces. Along the contour of the sealing lip, cut out a strip area with a width equal to the coating thickness in the area that may contact the rigid surface, such as Figure 4 As shown;

[0069] S4.2. Input the elastic modulus, Poisson's ratio, yield strength, tensile strength, elongation after fracture, thermal expansion coefficient, and thermal conductivity of the sealing ring base material, coating material, flange material, and fastener material as they change with temperature;

[0070] S4.3. Set a contact pair between the sealing ring and the rigid surface, set the rigid surface as the primary contact surface, and set the sealing lip, sealing ring limit surface and other areas on the sealing ring that may come into contact with the rigid surface as secondary contact surfaces. Select "Node-to-surface" for the discrete mode.

[0071] S4.4. Use quadrilateral axisymmetric linear heat transfer units to mesh the sealing ring geometry model, with the following requirements: 1) The coating area has a sufficiently fine grid (0.001-0.01 mm), with no less than 5 layers of units along the coating thickness direction, and the size of the coating unit along the normal direction of the sealing lip hub is twice the size along the contour line direction; 2) The remaining parts of the sealing ring are set with appropriate unit sizes (0.05-0.1 mm) to make the grid transition reasonable and the model scale appropriate; 3) The coating unit and the substrate unit are treated as common nodes; the final mesh division of the sealing lip is as follows Figure 4 shown.

[0072] S4.5. Apply thermal boundaries to the sealing ring and coating structure in the finite element model according to the temperature distribution calculated by fluid heat transfer, and establish a heat transfer analysis step: obtain the temperature field of the sealing ring and coating in the axisymmetric model through steady-state heat conduction;

[0073] S4.6. Change the unit type in step S4.4 to a quadrilateral axisymmetric linear reduced integration unit, set boundary constraints according to the stiffness distribution and force transmission characteristics of the actual system where the structure is located, and the calculation process is divided into two static analysis steps: the first step is to apply a displacement load to the rigid surface according to the compression amount extracted in step S3.7; the second step is to change the displacement load in the first step so that the remaining compression amount of the sealing ring structure is consistent with that in step S3.7, and at the same time read the temperature field calculated in step S4.5 to apply a temperature load to the sealing ring and the coating;

[0074] S4.7. After submitting the analysis and calculation, output and draw the curves of contact pressure and contact width changing with the loading history, and finally obtain the contact pressure ratio, contact force and contact width of the contact part between the sealing ring and the flange under the service state. Combined with the structural stress, strain distribution and separation amount in step S3.7, complete the detailed evaluation of the sealing performance of the regenerative cooling metal sealing flange structure.

Claims

1. A method for optimizing the sealing performance of a regenerative cooling metal sealing flange structure, characterized in that: The following steps are involved: S1. In the finite element software, a three-dimensional geometric model of the regenerative cooling metal sealing flange structure to be subjected to sealing optimization analysis is established, and performance parameters related to the temperature change of the regenerative cooling metal sealing flange structure material are imported; the cooling channel in the regenerative cooling metal sealing flange structure is simplified by the geometric trimming method, and the temperature distribution of the simplified metal sealing flange structure is made consistent with the actual temperature distribution of the metal sealing flange structure before simplification, so as to obtain a simplified regenerative cooling metal sealing flange structure model; S2. In the simplified regenerative cooling metal sealing flange structure model, identify the factors that affect the opening amount of the regenerative cooling metal sealing flange, obtain the influence ratio of the temperature load and the pressure load on the sealing performance of the regenerative cooling metal sealing flange structure, and judge whether the simplified regenerative cooling metal sealing flange structure strength and stiffness meet the preset indicators; if so, obtain the initial regenerative cooling metal sealing flange structure that meets the sealing performance, and then execute step S3; if not, return to step S1, and strengthen the regenerative cooling metal sealing flange structure until it meets the preset indicators; S3. Establish a three-dimensional geometric model of the initial regenerative cooling metal sealing flange structure, and then apply pressure load and temperature load to the initial regenerative cooling metal sealing flange structure that meets the sealing performance according to the service conditions of the regenerative cooling metal sealing flange structure, submit the calculation and obtain the strength and stiffness result data of the initial regenerative cooling metal sealing flange structure that meets the sealing performance under the service state, and extract the calculation data related to the sealing performance under the service state, that is, the opening amount and the residual compression amount; S4. Conduct a detailed evaluation and analysis on the sealing performance of the initial regenerative cooling metal sealing flange structure, establish a detailed analysis model for the sealing performance of the metal sealing flange structure, use the relevant calculation data extracted in step S3 as input to simulate the actual service conditions of the initial regenerative cooling metal sealing flange structure, obtain the sealing performance parameters of the initial regenerative cooling metal sealing flange structure under the actual service state, and combine the strength and stiffness evaluation data extracted in step S3 to complete the optimization analysis of the sealing performance of the regenerative cooling metal sealing flange structure.

2. According to claim 1, a method for optimizing the sealing performance of a regenerative cooling metal sealing flange structure is characterized in that: Step S1 is specifically as follows: S1.

1. In the finite element software, establish a three-dimensional geometric model of the regenerative cooling metal sealing flange structure for which sealing optimization analysis is to be performed; S1.

2. Import and export performance parameters related to temperature changes of regenerative cooling metal sealing flange structural materials; S1.3, simplifying the geometric mutation area in the cooling channel of the regenerative cooling metal sealing flange structure by means of geometric trimming; S1.

4. In the simplified finite element model, establish a temperature load analysis model and set boundary constraints and temperature loads; S1.

5. Calculate the temperature distribution of the metal sealing flange structure before simplification and the temperature distribution of the metal sealing flange structure after simplification through the temperature load analysis model, and compare and judge whether the temperature distributions of the two are consistent; If yes, proceed to step S2; if no, return to step S1.3, modify the geometric trimming method to simplify the cooling channel again until the temperature distribution of the two is consistent.

3. According to claim 2, a method for optimizing the sealing performance of a regenerative cooling metal sealing flange structure is characterized in that: In step S1.1, the three-dimensional geometric model of the regenerative cooling metal sealing flange structure does not include the sealing ring structure of the metal sealing flange.

4. According to claim 3, a method for optimizing the sealing performance of a regenerative cooling metal sealing flange structure is characterized in that: In step S1.2, the performance parameters related to temperature change include elastic modulus, Poisson's ratio, yield strength, tensile strength, elongation, thermal expansion coefficient and thermal conductivity.

5. According to claim 4, a method for optimizing the sealing performance of a regenerative cooling metal sealing flange structure is characterized in that: Step S2 is specifically as follows: S2.

1. In the simplified regenerative cooling metal sealing flange structure model, a mechanical load analysis model and a temperature load analysis model are established respectively, and the simplified regenerative cooling metal sealing flange structure three-dimensional geometric model is divided into finite element meshes; S2.

2. Set the displacement boundary according to the actual stiffness distribution and force transmission characteristics of the regenerative cooling metal sealing flange structure, submit the calculation and analysis of the mechanical load analysis model and the temperature load analysis model respectively, and obtain the opening amount of the regenerative cooling metal sealing flange under the pressure load and temperature load respectively; S2.

3. Compare and analyze the effects of mechanical load and temperature load on the opening of the regenerative cooling metal sealing flange, and then obtain the influence ratio of pressure load and temperature load on the sealing performance of the regenerative cooling metal sealing flange structure, and determine the optimization direction of the regenerative cooling metal sealing flange structure; S2.

4. Determine whether the strength and stiffness of the simplified regenerative cooling metal sealing flange structure meet the preset indicators; if so, obtain an initial regenerative cooling metal sealing flange structure that meets the sealing performance, and then execute step S3; if it does not meet the preset indicators, return to step S1, and use the optimization direction determined in step S2.3 to strengthen the regenerative cooling metal sealing flange structure until it meets the preset indicators.

6. According to claim 5, a method for optimizing the sealing performance of a regenerative cooling metal sealing flange structure is characterized in that: Step S3 is specifically as follows: S3.

1. Establish a three-dimensional geometric model of the initial regenerative cooling metal sealing flange structure that meets the sealing performance in finite element software; S3.

2. Performance parameters of the imported and regenerated cooling metal sealing flange structural materials related to temperature changes; S3.

3. According to the actual service conditions of the regenerative cooling metal sealing flange structure, the contact relationship and boundary conditions are applied to the initial regenerative cooling metal sealing flange structure that meets the sealing performance in the temperature load analysis model, and the temperature field calculation model is obtained by meshing the structure; the displacement boundary and the periodic symmetry boundary are set in the mechanical load analysis model, and the mechanical load calculation model is obtained by meshing the structure; S3.

4. According to the structural temperature distribution calculated by fluid heat transfer, the temperature load is applied to the temperature field calculation model of the initial regenerative cooling metal sealing flange structure, and the finite element temperature field result is obtained by submitting the calculation; S3.

5. Apply pressure load to the mechanical load calculation model according to the actual service conditions of the regenerative cooling metal sealing flange structure, import the finite element temperature field results in step S3.4, and submit the calculation to obtain the finite element results under the actual service conditions; S3.

6. Based on the finite element results in step S3.5, obtain the strength and stiffness evaluation data of the initial regenerative cooling metal sealing flange structure that meets the sealing performance under the service state, and extract the opening amount and residual compression amount of the initial regenerative cooling metal sealing flange structure under actual service conditions.

7. A method for optimizing the sealing performance of a regenerative cooling metal sealing flange structure according to claim 6, characterized in that: Step S4 is specifically as follows: S4.

1. Establish a sealing performance evaluation model for the initial regenerative cooling metal sealing flange structure; S4.

2. Performance parameters of the imported and regenerated cooling metal sealing flange structural materials related to temperature changes; S4.

3. According to the structural relationship of the actual service condition of the regenerative cooling metal sealing flange structure, the contact relationship and boundary conditions are applied in the sealing performance evaluation model, and the mesh is divided; S4.4, using the relevant calculation data extracted in step S3 as input, applying pressure load and temperature load to the sealing performance evaluation model to simulate the actual service condition of the initial regenerative cooling metal sealing flange structure; S4.

5. Extract the sealing performance parameters of the initial regenerative cooling metal sealing flange structure from the calculation results of the sealing performance evaluation model, and combine them with the strength and stiffness evaluation data extracted in step S3 to complete a detailed evaluation of the sealing performance of the regenerative cooling metal sealing flange structure.

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