CN-115795956-B - Liquid rocket engine flange structure optimization method and system

CN115795956BCN 115795956 BCN115795956 BCN 115795956BCN-115795956-B

Abstract

The invention discloses a flange structure optimization method and system of a liquid rocket engine, which comprise the steps of sampling and modeling all dimensional parameters of a flange structure to obtain a flange structure geometric model, carrying out first finite element mesh division on the flange structure geometric model, carrying out strength analysis, screening out a plurality of key dimensional parameters affecting the maximum equivalent stress S 1 of the flange structure by sensitivity analysis, carrying out flange structure tightness analysis on the flange structure geometric model, screening out a plurality of key dimensional parameters affecting the maximum separation d of the flange structure and the leakage rate L R of the flange structure by sensitivity analysis, respectively taking the maximum equivalent stress S 1 of the flange structure, the leakage rate L R of the flange structure and the weight M of the flange structure as output response values based on sampling sample points, establishing a Kriging proxy model, and establishing a flange structure optimization model and carrying out optimizing based on the Kriging proxy model.

Inventors

HU RUYI
ZHU JINGWEN
GONG XI
LIU KE
LI BIAO
WANG HONGYA
WANG ZHEN

Assignees

航天科工火箭技术有限公司

Dates

Publication Date: 20260508
Application Date: 20221125

Claims (9)

1. A method for optimizing a flange structure of a liquid rocket engine, the method comprising: S1, sampling all size parameters of a flange structure, and modeling based on sampling sample points to obtain a flange structure geometric model, wherein the flange structure comprises a first flange, a second flange, a sealing ring, a bolt and a nut; s2, performing first finite element mesh division on the flange structure geometric model, setting material properties of parts of the flange structure, applying load and boundary conditions to perform strength analysis, and using the maximum equivalent stress of the flange structure Screening out the maximum equivalent stress to the flange structure by sensitivity analysis for the target response value Influencing a plurality of critical dimension parameters in the past; s3, performing second finite element mesh division on the flange structure geometric model, setting material properties of all parts of the flange structure, applying load and boundary conditions to perform flange structure tightness analysis, and using the maximum separation amount of the flange structure Leakage rate of flange structure For target response value, the maximum separation amount of the flange structure is respectively screened out through sensitivity analysis Leakage rate of flange structure Influencing a plurality of critical dimension parameters in the past; s4, based on the sampling sample points, respectively using the maximum equivalent stress of the flange structure Maximum separation of flange structure Leakage rate of flange structure The flange structure weight M is taken as an output response value, and a Kriging proxy model between the output response value and the key size parameter of the corresponding flange structure is established; S5, constructing a critical dimension parameter range of the flange structure, constructing a flange structure optimization model based on the Kriging agent model constructed in S4 and optimizing, if the optimization model is converged, obtaining an optimal solution or a better solution of the flange structure, if the optimization model is not converged, returning to S4, increasing sampling sample points to update the Kriging agent model until the optimization model is converged, wherein in S5, the flange structure optimization model uses the maximum equivalent stress of the flange structure Maximum separation of flange structure Leakage rate of flange structure Takes the flange structure weight M as an objective function as a constraint condition, and takes the flange structure optimization model expression as In which, in the process, The weight of the flange structure in the flange structure optimization model; The maximum equivalent stress of the flange structure in the flange structure optimization model is expressed in MPa; the leakage rate of the flange structure in the flange structure optimization model is expressed as Pa.m 3 /s; Maximum separation amount of the flange structure in the flange structure optimization model is in mm; the key dimension parameter set of the flange structure is in mm; The allowable stress of the flange structure is expressed in MPa; the allowable leakage rate of the flange structure is expressed as Pa.m 3 /s; The flange structure permits a separation amount in mm; The upper and lower limits of the key size parameters of the flange structure are in mm.
2. The method of claim 1, wherein prior to S1, the method further comprises: and simplifying the model of the flange structure, establishing a parameterized model, and determining all dimension parameters of the flange structure.
3. The method of claim 1, wherein in S2, the flange structure portion is configured as the first flange and the second flange; the applied load includes medium pressure and temperature loads; The boundary condition is that the sealing end surfaces of the first flange and the second flange are in friction contact, and the first flange and the second flange are far away from the sealing surface end surface to apply fixed constraint.
4. The method of claim 1, wherein after the applying load and boundary conditions for intensity analysis, the method further comprises: extracting the maximum equivalent stress of the flange structure And the first flange or the second flange is far away from the acting force F of the end face of the sealing ring.
5. The method of claim 1, wherein said setting material properties of all components of said flange structure, applying load and boundary conditions for flange structure sealability analysis, specifically comprises: setting the material properties of a sealing ring, a bolt and a nut in the flange structure; And setting the material properties of the first flange and the second flange according to the material properties set in the step S2.
6. The method of claim 4, wherein in S3, the applied load comprises a media pressure, a conduit force, and a bolt preload; the conduit acting force is acting force F of the first flange or the second flange far away from the end face of the sealing ring and is applied to the end face of the corresponding flange far away from the sealing face; the calculation formula of the bolt pretightening force is as follows In which, in the process, Bolt pretension in units of ; -Bolt torque in units of ; The torque coefficient is in a value range of 0.18-0.21; The diameter of the bolt is in mm; The boundary conditions are that friction contact is formed between the sealing ring and the corresponding flange, between the first flange and the second flange and between the bolt nut and the corresponding flange, and the first flange is far away from the end face of the sealing surface to apply fixed constraint.
7. The method of claim 1, wherein in S3, the flange structure leak rate The calculation formula is that In the formula, Leakage rate, the unit is Pa.m 3 /s; The ratio of the dynamic viscosity of the medium to the dynamic viscosity of the helium at the normal temperature of 1 MPa; The medium pressure is expressed in MPa; minimum stress of the sealing ring is expressed in MPa; and fitting test data to obtain the gasket coefficient of the sealing ring.
8. The method of claim 1, wherein the Kriging proxy model expression is In the formula, A response value; the key dimension parameter set of the flange structure is in mm; the basis function is regressed to the set of functions, ; The regression coefficient is used to determine the regression coefficient, ; Mean value 0, variance Is a random distribution error of (c).
9. A liquid rocket engine flange structure optimization system, the system comprising: The first modeling unit is used for executing S1, sampling all size parameters of the flange structure, and modeling based on sampling sample points to obtain a flange structure geometric model, wherein the flange structure comprises a first flange, a second flange, a sealing ring and bolts and nuts; A first analysis unit for performing S2, performing first finite element mesh division on the flange structure geometric model, setting material properties of the flange structure part, applying load and boundary conditions for strength analysis, and using the maximum equivalent stress of the flange structure Screening out the maximum equivalent stress to the flange structure by sensitivity analysis for the target response value Influencing a plurality of critical dimension parameters in the past; A second analysis unit for executing S3, performing a second finite element mesh division on the flange structure geometric model, setting material properties of all parts of the flange structure, applying load and boundary conditions to perform flange structure tightness analysis, and using the maximum separation amount of the flange structure Leakage rate of flange structure For target response value, the maximum separation amount of the flange structure is respectively screened out through sensitivity analysis Leakage rate of flange structure Influencing a plurality of critical dimension parameters in the past; a second modeling unit for executing S4 based on the sampling sample points with maximum equivalent stress of the flange structure Maximum separation of flange structure Leakage rate of flange structure The flange structure weight M is taken as an output response value, and a Kriging proxy model between the output response value and the key size parameter of the corresponding flange structure is established; The third modeling unit is used for executing S5, wherein the critical dimension parameter range of the flange structure is built, a flange structure optimization model is built and optimized based on the Kriging agent model built in S4, an optimal solution or a better solution of the flange structure is obtained if the optimization model is converged, the sampling sample point is added to update the Kriging agent model in S4 if the optimization model is not converged, until the optimization model is converged, and in S5, the flange structure optimization model uses the maximum equivalent stress of the flange structure Maximum separation of flange structure Leakage rate of flange structure Takes the flange structure weight M as an objective function as a constraint condition, and takes the flange structure optimization model expression as In which, in the process, The weight of the flange structure in the flange structure optimization model; The maximum equivalent stress of the flange structure in the flange structure optimization model is expressed in MPa; the leakage rate of the flange structure in the flange structure optimization model is expressed as Pa.m 3 /s; Maximum separation amount of the flange structure in the flange structure optimization model is in mm; the key dimension parameter set of the flange structure is in mm; The allowable stress of the flange structure is expressed in MPa; the allowable leakage rate of the flange structure is expressed as Pa.m 3 /s; The flange structure permits a separation amount in mm; The upper and lower limits of the key size parameters of the flange structure are in mm.

Description

Liquid rocket engine flange structure optimization method and system Technical Field The application relates to the technical field of liquid rocket engines, in particular to a method and a system for optimizing a flange structure of a liquid rocket engine. Background The flange connection structure is widely applied to a large-diameter pipeline system of a liquid rocket engine due to the advantages of high strength, simple structure, repeated disassembly and the like, and is usually sealed by adopting a sealing ring. Because the working condition of the liquid rocket engine is complex, the flange structure needs to bear high-pressure and low-temperature load environments, and under the combined action of temperature and pressure, the flange deforms to cause tiny separation of the sealing surface, so that the local compression force of the gasket is greatly reduced, propellant leakage and fire can be caused, and the requirement on the tightness of the flange structure needs to be highly concerned in design. In addition, the weight of the liquid rocket engine is a key factor influencing rocket carrying capacity, so that the liquid rocket engine with a flange structure is necessary to carry out structural optimization design, however, the flange structure has a plurality of sizes, the finite element simulation calculation amount involved in the optimization design is large, and the optimization efficiency is low by adopting a traditional optimization method. Disclosure of Invention In view of the above, the invention provides a method and a system for optimizing a flange structure of a liquid rocket engine, which are characterized in that a Kriging proxy model is adopted to replace a complex finite element simulation model, influence factors of flange structure strength and tightness are comprehensively considered, a flange structure optimizing model is established, and the flange structure is optimally designed, so that the calculation cost of flange structure optimization is reduced, and the optimization efficiency is improved. In order to solve the technical problems, the first aspect of the invention discloses a liquid rocket engine flange structure optimization method, which comprises the following steps: S1, sampling all size parameters of a flange structure, and modeling based on sampling sample points to obtain a flange structure geometric model, wherein the flange structure comprises a first flange, a second flange, a sealing ring, a bolt and a nut; S2, performing first finite element mesh division on the flange structure geometric model, setting material properties of parts of the flange structure, applying load and boundary conditions to perform strength analysis, responding to the maximum equivalent stress S 1 of the flange structure as a target, and screening out a plurality of critical dimension parameters affecting the maximum equivalent stress S 1 of the flange structure through sensitivity analysis; S3, performing second finite element mesh division on the flange structure geometric model, setting material properties of all parts of the flange structure, applying load and boundary conditions to perform flange structure tightness analysis, taking the maximum separation amount d of the flange structure and the leakage rate L R of the flange structure as target responses, and respectively screening out a plurality of critical dimension parameters affecting the maximum separation amount d of the flange structure and the leakage rate L R of the flange structure through sensitivity analysis; S4, based on the sampling sample points, respectively taking the maximum equivalent stress S 1 of the flange structure, the maximum separation d of the flange structure, the leakage rate L R of the flange structure and the weight M of the flange structure as output response values, and establishing a Kriging proxy model between the output response values and key size parameters of the corresponding flange structure; S5, constructing a critical dimension parameter range of the flange structure, building a flange structure optimization model based on the Kriging proxy model constructed in the S4, optimizing, obtaining an optimal solution or a better solution of the flange structure if the optimization model is converged, and returning to the S4, increasing sampling sample points to update the Kriging proxy model until the optimization model is converged if the optimization model is not converged. Preferably, before S1, the method further comprises: and simplifying the model of the flange structure, establishing a parameterized model, and determining all dimension parameters of the flange structure. Preferably, in the step S2, the flange structure part is configured as the first flange and the second flange; the applied load includes medium pressure and temperature loads; The boundary condition is that the sealing end surfaces of the first flange and the second flange are in friction contact, and the first flange