A method and system for predicting time-dependent leakage rate of a nuclear power plant gate O-ring

Abstract

The present application belongs to the field of nuclear power technology, and discloses a nuclear power gate O-ring time correlation leakage rate prediction method and system, comprising: simulating the thermal coupling condition, and simulating the mechanical deformation characteristics of the gate O-ring; combining the aging data, and performing finite element analysis on the long-term relaxation characteristics of the gate O-ring under the thermal coupling condition; through micro-contact finite element analysis of the sealing structure, a quantitative relationship between the actual height h of the rough channel and the average contact stress SG is established; a leakage rate calculation model is established based on the leakage channel flow analysis; and influence factor analysis and long-term sealing performance evaluation are performed. The present application is suitable for predicting the long-term leakage rate of the gate under the thermal coupling condition. The model is established on the basis of mature mechanism research, the prediction value has high accuracy, the test and trial cost can be reduced to the greatest extent, and the design cost can be greatly reduced.

Description

Technical Field

[0001] This invention belongs to the field of nuclear power technology, and in particular relates to a method and system for predicting the time-related leakage rate of the O-ring of a nuclear power plant gate. Background Technology

[0002] The containment building is the last physical barrier in the defense-in-depth principle of a nuclear power plant. To ensure that the radioactivity released into the external environment during an accident meets design requirements, the leakage rate of the containment building is strictly limited. Personnel gates, equipment gates, and other gates are important components of the containment building. They provide access for personnel and equipment while also meeting design requirements for integrity and tightness under all operating conditions. Therefore, the prediction and control of gate sealing performance, especially under accident conditions, is of great significance to the safety of nuclear power plants.

[0003] The sealing of containment gates is primarily achieved through O-ring rubber seals. On-site leakage rate detection and sealing performance testing under simulated LOCA (Local Occurrence-Based Accident) conditions are currently the main control methods for gate sealing performance. However, these tests are extremely time-consuming and labor-intensive, and cannot provide any predictive information. CN204944760U proposes a comprehensive sealing performance testing device for personnel gates capable of simulating LOCA accidents or pressure tests. This device achieves rapid and accurate online detection of the overall sealing performance of personnel gates through a separate gas path connection method for pressure inflation / deflation and pressure measurement points, and dedicated leakage rate measurement software. However, this method is only suitable for verifying the leakage rate at the time of the incident and cannot predict the potential safety risks arising from the decline in sealing performance of rubber materials due to long-term aging under thermo-coupling conditions.

[0004] The impact of high temperature and high pressure on the long-term sealing performance of gates is usually investigated through studies on the aging properties of rubber materials. For example, GB / T 20028-2005 specifies a 50% change in the physical properties of rubber after aging as the critical value for seal failure, while CN201611174320 proposes a compression set CS ≥ 40% as the critical standard for seal failure. Chinese patents CN110765692A and CN113295400A, based on the Arrhenius equation and aging kinetics equation, obtain the aging laws of rubber materials and propose a life prediction method based on aging indices. However, the evaluation indices used in these methods are often not directly related to long-term sealing performance and are all empirical. The methods for determining the relevant life critical values ​​are not clearly defined, lack universality, and are particularly lacking in basis for nuclear power plant safety.

[0005] In summary, the most direct indicator for the safety assessment of nuclear power plant gate sealing structures is the leakage rate under accident conditions. The leakage rate is related to various factors, including the dimensions of the sealing structure, the sealing force applied, and the aging characteristics of the sealing material. Current methods for detecting gate leakage rates and studies on the aging patterns of rubber seals cannot accurately assess the long-term sealing performance of gate sealing structures under accident conditions, nor can they quantitatively evaluate the impact of various influencing factors on long-term sealing performance. Therefore, there is a lack of sufficient guidance for the reliable forward design of gate sealing structures under accident conditions.

[0006] Based on the above analysis, the existing technologies have the following problems and shortcomings: Current gate leakage rate detection methods and studies on the aging patterns of rubber seals cannot accurately assess the long-term sealing performance of gate sealing structures under accident conditions, nor can they quantitatively evaluate the impact of various influencing factors on long-term sealing performance. Furthermore, there is a lack of sufficient guidance for the reliable forward design of gate sealing structures under accident conditions. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention provides a method and system for predicting the time-related leakage rate of the O-ring of a nuclear power plant gate.

[0008] This invention is implemented as follows: a method for predicting the time-related leakage rate of an O-ring in a nuclear power plant valve, comprising:

[0009] S1. Establish a finite element model of the gate O-ring under thermo-coupling conditions and analyze the mechanical properties of the O-ring; based on the initial conditions (compression ratio C)... i Calculate the contact width and initial contact stress corresponding to different compression ratios and temperatures (T, T); observe the patterns in the simulation data, and adjust the initial contact stress S based on various factors. G0 The influence patterns were established separately for S. G0 / S Gr =g1(T) and S Gr =g2(C i ), where S Gr The initial contact stress at the reference temperature; denoted as S G0 =(S G0 / S Gr )×S Gr The initial contact stress S under thermo-coupling conditions is established in the form of... G0 With compression ratio C i Relationship with temperature T: S G0 =f(C i ,T);

[0010] S2, a finite element method is established for the long-term relaxation analysis of the gate O-ring under thermo-coupling conditions, simulating the long-term relaxation characteristics of the O-ring under thermo-coupling conditions; the contact stress S of the O-ring under different compression ratios and aging temperatures is output. G Curve showing the change over time; definition of dimensionless contact stress S G / S G0 , with S G / S G0 To determine the long-term performance indicators of the sealing ring, based on the aging kinetic model and Aronus's formula, and using numerical simulation results, a dimensionless contact stress S for the gate seal is established. G / S G0 -Temperature T-Time τ Relationship: S G / S G0 =f(T,τ);

[0011] S3, based on numerical analysis of microscopic contact mechanics of rough interfaces, establishes the contact stress S G The quantitative relationship between the separation height h from the sealing interface and the following: h = f(S) G );

[0012] S4. Based on numerical reconstruction of rough surfaces and numerical simulation of interfacial leakage flow characteristics, the relationship between leakage rate Q and sealing surface roughness parameters σ and A is established. T The quantitative relationship between sealing medium pressure P, sealing interface contact width B, and sealing interface separation height h is: Q = f(B, P, σ, A) T ,h);

[0013] By combining S5 with S1 to S4, we can obtain the variation law of the leakage rate Q of a given sealing structure with respect to compression ratio, temperature, and time, that is: Q = f(C i ,T,τ);

[0014] S6 Influencing Factors Analysis and Sealing Performance Evaluation: Given operating parameters (temperature T, medium pressure P, compressibility C) i Using the allowable leakage rate of the containment gate as a safety criterion, and the service time τ, the long-term sealing performance of the gate under thermal coupling conditions is evaluated.

[0015] Furthermore, S1 simulates the mechanical properties of the O-ring under thermo-coupling conditions and establishes a functional relationship for the initial contact stress, specifically including the following steps:

[0016] S101, Set the reference aging temperature T r Establish T r Initial contact stress S Gr With compression ratio C i Relationship: S Gr =f(C i The specific method is as follows:

[0017] (1) Establish a finite element analysis model of the sealing structure; (2) Select an appropriate constitutive equation to describe the hyperelastic properties of the rubber; (3) Input the thermophysical parameters of the sealing material; (4) Apply a displacement load to achieve the set compression ratio C. i (5) By setting the temperature boundary T r Simulate the environment at the reference aging temperature; (6) Obtain S Gr (7) Change the compression ratio, repeat the calculation, and obtain another S. Gr (8) Through multiple sets of calculations, fit S Gr Regarding C i Function: S Gr =g1(C i );

[0018] S102, Set compression ratio C i To obtain the S of the O-ring at a set compression rate G0 / S Gr The relationship with different aging temperatures T is as follows: (1) Change the aging temperature T and repeat the same finite element analysis as in the previous step to obtain the initial contact stress S of the O-ring at different aging temperatures. G0 (2) With the same compression ratio C i The reference temperature T r The corresponding initial contact stress S Gr As a characteristic quantity, the initial contact stress S at multiple temperatures is... G0 Dimensionless, i.e., S G0 / S Gr (3) Establish S G0 / S Gr A function of aging temperature T: S G0 / S Gr =g2(T);

[0019] S103. Establish the initial contact stress S under thermo-coupling conditions. G0 With compression ratio C i Relationship with temperature T: S G0 =f(C i The specific method is as follows: (1) Change the compression ratio C i Repeat step S102 to obtain multiple sets of compression ratios C. i S below G0 / S Gr Data corresponding to different aging temperatures T; (2) Observing the numerical calculation results, it can be found that the compression ratio C i For S G0 / S Gr The effect of S on the functional relationship with temperature T is very weak, therefore S can be considered as... G0 / SGr S is a single-valued function of temperature T, i.e.: G0 / S Gr =g2(T); (3) with S G0 =(S G0 / S Gr )×S Gr In the form of S, we obtain S G0 With C i The relationship between S and T: G0 =f(C i ,T).

[0020] Furthermore, S2 simulates the long-term relaxation characteristics of the O-ring under thermo-coupling conditions and establishes a functional relationship describing the long-term change of the O-ring contact stress over time under thermo-coupling conditions. This process includes the following steps:

[0021] S201. Based on the finite element simulation method, simulate the stress relaxation characteristics of O-rings under thermo-coupling conditions. The specific method is as follows: (1) Add a relaxation step after the finite element analysis step in S1 and set the relaxation time τ; (2) Based on the stress relaxation test measurement data of rubber materials, establish a generalized Maxwell model describing the viscoelastic properties of rubber; (3) Based on the simulation of the relaxation process, obtain the contact stress S corresponding to different relaxation times τ. G (4) Plot the compression ratio C at different rates i S corresponding to aging temperature T G -τ curve.

[0022] S202. Observe the effects of various factors on S G -τ curve, establishing contact stress S G Regarding the relationship between aging temperature T and relaxation time τ, the specific method is as follows: (1) Define the dimensionless contact stress S G / S G0 S G0 The initial contact stress corresponding to the same compression ratio and the same aging temperature; dimensionless contact stress can indicate the degradation characteristics of the sealing performance of rubber O-rings under stress and aging temperature; (2) with S G / S G0 As an aging index, S is established using the aging kinetic equation and the Aronius formula. G / S G0 (3) The numerical results are organized into different compression ratios C. i S under different aging temperatures T and different aging times τ G / S G0 (4) Substitute the numerical solution into S G / S G0 The function of aging temperature T and aging time τ is used to solve for the correlation coefficient in the function and establish S.G / S G0 The specific expressions for temperature T and time τ: S G / S G0 =f(T,τ);

[0023] S203, the S obtained from S1 is... G0 =f(C i ,T) and S G / S G0 By combining f(T,τ), we can obtain S under thermo-mechanical coupling. G Calculation formula:

[0024] Furthermore, S3 establishes a microscopic contact mechanics model for the micro-roughness peak. Finite element analysis is used to establish the relationship between the sealing surface separation height h and the average contact stress S. G The functional relationship between them includes the following steps:

[0025] S301. Based on the measurement of the micro-morphology of the sealing surface or the machining parameters, establish a micro-contact analysis model for the rough surface;

[0026] S302. Through finite element analysis of the micro-contact process on rough surfaces, the average contact stress S is established. G The correspondence between the separation height h of the contact interface (effective height of the leakage channel);

[0027] S303, Hertz elastic contact theory gives S G The function form between h and [the other element] is used. Substituting the numerical results, the formula for calculating the separation height of the rubber O-ring sealing interface can be established: h = f(S). G ).

[0028] Furthermore, S4 is the flow analysis of the leakage channel at the sealing interface under thermo-coupling conditions, which specifically includes the following steps:

[0029] S401. Based on the surface micromorphology parameters obtained in S3, a three-dimensional numerical rough surface is established, which forms a sealing interface leakage channel with a smooth surface having a certain separation distance h.

[0030] S402. Set the sealing interface separation height h0 when the average contact stress is 0, which depends only on the sealing surface roughness σ; set the sealing interface separation height h under a certain average contact stress, which is related to the contact stress S. G The relationship depends on the results of the micro-contact mechanics analysis of the S3 rough interface;

[0031] S403. Using a mesoscopic analysis model of the leakage channel flow, numerical simulations were performed on the interfacial leakage flow with height h0 composed of surfaces with different roughness characteristics. The influence of surface roughness on the flow characteristics of the sealing interface was obtained, and a functional relationship of the following form was established: Q0 / Q p =f(σ,A) T Among them, the average roughness σ and the autocorrelation length A T Q is one of two statistical parameters reflecting surface roughness characteristics. p To determine the leakage rate of a leakage channel consisting of two smooth surfaces with a separation height of h0; Q0 / Q p The roughness factor Φ is defined as the leakage rate. σ Then we have: Φ σ =Q0 / Q p =f(σ,A) T );

[0032] S404. Using a mesoscopic analysis model of the leakage channel flow, numerical simulations are performed on the interfacial leakage flow with different separation heights h, formed by surfaces with the same roughness characteristics. The influence of the separation height on the flow characteristics of the sealing interface is obtained, and a functional relationship of the following form is established: Q / Q0=f(h); where Q0 is the leakage rate of a leakage channel with a separation height of h0 (the channel height corresponding to zero contact stress) formed by a given roughness surface; Q / Q0 is defined as the height factor Φ of the leakage rate. h Establish Φ based on numerical results h The functional relationship between the contact height h and the contact height is: Q = Q / Q0 = f(h);

[0033] S405. Establish the formula for calculating the leakage rate of the sealing interface: Q = Φ σ ×Φ h ×Q p Q p This is the leakage rate of a leakage channel with a height of h0 (the channel height corresponding to zero contact stress) formed by a smooth surface; this formula can be extended from the mesoscopic to the macroscopic; for O-rings, Q p Poiseuille's law, which describes the flow between parallel plates, can be used for calculation. In this case, the geometric dimensions of the leakage channel are the O-ring contact width B and the average circumference L, and the pressure difference is the pressure difference P between the inside and outside of the O-ring. Finally, we can obtain: Q = f(B, P, σ, A) T ,h).

[0034] Another object of the present invention is to provide a nuclear power plant valve O-ring time-related leakage rate prediction system that applies the aforementioned nuclear power plant valve O-ring time-related leakage rate prediction method, comprising:

[0035] The finite element model building module is used to build a finite element model of a gate O-ring under thermo-coupling conditions and analyze the mechanical properties of the O-ring; based on initial conditions (compression ratio C)... i Calculate the contact width and initial contact stress corresponding to different compression ratios and temperatures (T, T); observe the patterns in the simulation data, and adjust the initial contact stress S based on various factors. G0 The influence patterns were established separately for S. G0 / S Gr =g1(T) and S Gr =g2(C i ), where S Gr The initial contact stress at the reference temperature; denoted as S G0 =(S G0 / S Gr )×S Gr The initial contact stress S under thermo-coupling conditions is established in the form of... G0 With compression ratio C i Relationship with temperature T: S G0 =f(C i ,T);

[0036] The finite element method (FEM) module is used to establish a FEM for long-term relaxation analysis of gate O-rings under thermo-coupling conditions, simulating the long-term relaxation characteristics of O-rings under thermo-coupling conditions; it outputs the O-ring contact stress S under different compression ratios and aging temperatures. G Curve showing the change over time; definition of dimensionless contact stress S G / S G0 , with S G / S G0 To determine the long-term performance indicators of the sealing ring, based on the aging kinetic model and Aronus's formula, and using numerical simulation results, a dimensionless contact stress S for the gate seal is established. G / S G0 -Temperature T-Time τ Relationship: S G / S G0 =f(T,τ);

[0037] The contact mechanics numerical analysis module is used for numerical analysis of microscopic contact mechanics based on rough interfaces, and to establish the contact stress S. G The quantitative relationship between the separation height h from the sealing interface and the following: h = f(S) G );

[0038] The flow characteristic numerical simulation module is used for numerical reconstruction of flow characteristics based on rough surfaces and interface leakage, establishing the relationship between leakage rate Q and the roughness parameters σ and A of the sealing surface. T The quantitative relationship between sealing medium pressure P, sealing interface contact width B, and sealing interface separation height h is: Q = f(B, P, σ, A) T,h);

[0039] The variation law acquisition module is used to obtain the variation law of the leakage rate Q of a given sealing structure with respect to compression ratio, temperature and time, that is: Q=f(C i ,T,τ);

[0040] Influencing Factor Analysis and Sealing Performance Evaluation Module: Used for given operating parameters (temperature T, medium pressure P, compressibility C) i Using the allowable leakage rate of the containment gate as a safety criterion, and the service time τ, the long-term sealing performance of the gate under thermal coupling conditions is evaluated.

[0041] Another object of the present invention is to provide a computer device, the computer device including a memory and a processor, the memory storing a computer program, and when the computer program is executed by the processor, causing the processor to perform the steps of the nuclear power plant gate O-ring time-related leakage rate prediction method.

[0042] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of the nuclear power plant gate O-ring time-related leakage rate prediction method.

[0043] Another objective of this invention is to provide an information data processing terminal for implementing the aforementioned nuclear power plant gate O-ring time-related leakage rate prediction system.

[0044] Based on the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solution to be protected by this invention are as follows:

[0045] First, regarding the technical problems existing in the above-mentioned prior art, the creative technical effects resulting from solving these problems are described in detail below:

[0046] 1. This invention proposes a method that combines O-ring stress relaxation with numerical research on leakage rate, and establishes a quantitative relationship between gate leakage rate and time under thermo-coupling conditions, thus solving the problem of predicting the long-term leakage rate of nuclear power plant gate O-rings.

[0047] 2. The long-term leakage rate prediction model for O-ring gates established based on this invention can predict the lifespan and assess the safety of the gate sealing structure based on the maximum allowable leakage rate. The leakage rate of gates under accident conditions is a crucial safety indicator in the nuclear power field. This invention provides guidance for the safe design of gate sealing structures and the reasonable determination of the service life of O-rings, thereby improving the safety and economy of nuclear power plants.

[0048] Secondly, the time-related leakage rate prediction method proposed in this invention can quantitatively characterize the relationship between material stress relaxation characteristics and leakage rate. It can not only directly determine the safety status of the gate sealing structure, but also reveal the influence law of various factors, providing guidance for improving the safety design of sealing structures.

[0049] The predictive model proposed in this invention is based on a theoretical model that combines multiple physical mechanisms. It effectively reveals the quantitative relationship between physical quantities and is the key technology of this invention. Based on this key technology, for a given sealing structure and sealing material, the model can be directly applied to calculate the leakage rate corresponding to operating parameters and time, thus determining safety and reliability, without the need for repeated numerical calculations.

[0050] Third, the expected benefits and commercial value of the technical solution of this invention after its transformation are as follows: Predicting the long-term leakage rate of gate O-rings under accident conditions is of great significance to nuclear safety. Previously, the safety and long-term reliability of gate sealing structures could not be quantitatively assessed, and safety had to be ensured at the expense of economic efficiency. After the transformation of the technical solution of this invention, the service life of O-rings can be assessed more accurately, potentially improving the economics of gate sealing design. Simultaneously, theoretical guidance for experiments can reduce the number of tests or maximize the application scope of the test results.

[0051] The technical solution of this invention solves a long-standing but unresolved technical problem: the inability to predict the long-term variation of gate O-ring leakage rate under thermo-coupling conditions. The proposed approach, combining stress relaxation and numerical leakage rate research methods, quantitatively assesses the impact of thermo-coupling conditions on the relaxation characteristics of sealing materials and further establishes a quantitative relationship between relaxation characteristics and leakage rate. Gate leakage rate under accident conditions is a crucial safety indicator in the nuclear power field; this invention can significantly improve the safety and economy of nuclear power plants.

[0052] Fourth, the significant technological advancements brought about by the nuclear power plant gate O-ring time-related leakage rate prediction method provided by this invention include:

[0053] 1) Accurate leakage rate prediction: Through integrated analysis of multiple steps (S1-S6), accurate predictions of the leakage rate of nuclear power plant gate O-rings as a function of time, temperature and compressibility are provided, thereby enhancing the safety and reliability of nuclear power plants.

[0054] 2) Adaptability under complex environments: This method takes into account thermo-mechanical coupling conditions and can simulate and analyze the long-term relaxation characteristics and sealing performance of O-rings under complex environments, thus providing an important reference for the long-term operation of nuclear power plants.

[0055] 3) Application of micro-contact mechanics: Through numerical analysis of micro-contact mechanics of rough interfaces, a quantitative relationship between contact stress and separation height of the sealing interface was established, which improved the accuracy of the prediction method.

[0056] 4) Comprehensive evaluation of sealing performance: Combining different physical models and numerical simulations, a comprehensive evaluation of sealing performance was conducted, which can accurately determine the sealing performance under different working conditions and predict the occurrence of sealing failures.

[0057] 5) Consideration of leakage flow characteristics: Numerical simulation of rough surface reconstruction and interface leakage flow characteristics ensures the comprehensiveness and accuracy of leakage rate prediction.

[0058] 6) Comprehensive analysis of influencing factors: By analyzing various influencing factors, such as compression ratio, temperature, and time, the comprehensiveness and integration of leakage rate prediction are ensured.

[0059] 7) Improve nuclear power safety: This method provides a scientific basis for the maintenance of O-rings on nuclear power plant gates, which helps to prevent and resolve sealing problems in advance, thereby improving the operational safety of nuclear power plants.

[0060] The time-related leakage rate prediction method for nuclear power plant gate O-rings provided by this invention has the advantages of high accuracy, adaptability to complex environments, and comprehensive evaluation of sealing performance, which is of great significance for improving the safe operation of nuclear power plants. Attached Figure Description

[0061] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0062] Figure 1 This is a flowchart of the gate sealing safety assessment implementation steps provided in this embodiment of the invention;

[0063] Figure 2 This is a schematic diagram of the finite element analysis model provided in an embodiment of the present invention;

[0064] Figure 3 This is a schematic diagram of the mechanical analysis steps provided in an embodiment of the present invention; wherein, (a) assembly, (b) compression, and (c) heating;

[0065] Figure 4 This is the S provided in the embodiments of the present invention. Gr With C i Relationship diagram;

[0066] Figure 5 This is the S provided in the embodiments of the present invention.G0 / S Gr A schematic diagram showing the relationship between temperature T and temperature;

[0067] Figure 6 This is a schematic diagram of the long-term relaxation characteristic analysis step settings provided in the embodiment of the present invention; wherein, (a) combination, (b) compression, (c) heating, (d) relaxation, and (e) unloading;

[0068] Figure 7 The embodiments of the present invention provide S at different temperatures G The graph shows the variation with τ;

[0069] Figure 8 This is the S provided in the embodiments of the present invention. G / S G0 A graph showing the relationship between -T and τ;

[0070] Figure 9 This is a schematic diagram of the microscopic contact analysis model provided in an embodiment of the present invention;

[0071] Figure 10 This is a schematic diagram of the leakage channel height provided in an embodiment of the present invention;

[0072] Figure 11 This is a schematic diagram of the microscopic contact mechanics simulation results provided in the embodiments of the present invention; wherein, (a) different elastic moduli, and (b) different roughness peak heights;

[0073] Figure 12 This is a schematic diagram of the gap flow analysis model provided in an embodiment of the present invention;

[0074] Figure 13 The Φ provided in the embodiments of the present invention σ Fitting results graph;

[0075] Figure 14 The Φ provided in the embodiments of the present invention h Fitting results graph;

[0076] Figure 15 This is a schematic diagram of an ideal leakage path for an O-ring provided in an embodiment of the present invention;

[0077] Figure 16 This is the safety assessment result of the gate sealing O-ring provided in the embodiment of the present invention; wherein, (a) different temperatures T1, T2, T3, T4, T5 are selected, other parameters are determined, and the O-ring leakage rate at different times is calculated; (b) different medium pressures P1, P2, P3, P4, P5 are selected, other parameters are determined, and the O-ring leakage rate at different times is calculated; (c) different compression ratios C are selected. i1 C i2 C i3Once other parameters are determined, the O-ring leakage rate at different times is calculated.

[0078] Figure 17 This is a schematic diagram of a nuclear power plant gate O-ring time-related leakage rate prediction system provided in an embodiment of the present invention. Detailed Implementation

[0079] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0080] To address the problems existing in the prior art, this invention provides a method and system for predicting the time-related leakage rate of the O-ring of a nuclear power plant gate. The invention will be described in detail below with reference to the accompanying drawings.

[0081] The following are two specific application examples and their detailed implementation schemes:

[0082] Example 1: Evaluation of the sealing performance of nuclear power plant gates

[0083] This predictive method was applied to a containment gate at a nuclear power plant to assess its sealing performance during long-term operation.

[0084] 1) Data collection and model establishment: Based on the actual operating data of the nuclear power plant, including the material, size, temperature, pressure and other conditions of the O-rings of the containment gate, a finite element model of the O-ring under thermo-coupling conditions is established.

[0085] 2) Simulation and Analysis: Simulate the actual working conditions of a nuclear power plant, including temperature fluctuations and compressibility changes. Use the method of this invention to perform long-term relaxation characteristic analysis and output the curve of contact stress change over time.

[0086] 3) Leakage rate calculation: Based on the obtained contact stress data and the specific operating parameters of the nuclear power plant, the leakage rate of the gate O-ring is calculated.

[0087] 4) Performance evaluation: Using the safe leakage rate specified by the nuclear power plant as the standard, evaluate the long-term sealing performance of the gate and predict the time point when maintenance or replacement of O-rings is required.

[0088] Example 2: Nuclear Power Plant Gate Maintenance Plan Development

[0089] This provides a method for nuclear power plant maintenance teams to develop more effective gate maintenance plans.

[0090] 1) Parameter setting and simulation: Based on the maintenance records of the nuclear power plant and the historical data of O-rings, set the corresponding initial conditions, such as the aging temperature and compression ratio of the O-rings.

[0091] 2) Long-term relaxation characteristics analysis: The method of this invention is used to simulate the long-term relaxation characteristics of O-rings under preset conditions, and the performance changes at different times and temperatures are analyzed.

[0092] 3) Leakage rate prediction: Based on the analysis results, predict the leakage rate of the O-ring under different operating conditions to determine whether it meets the safety operation requirements of the nuclear power plant.

[0093] 4) Maintenance plan development: Based on the forecast results, develop a specific maintenance plan for the nuclear power plant, including the inspection, testing and replacement time of O-rings, to ensure the long-term sealing performance of the gates and the safe operation of the nuclear power plant.

[0094] The two embodiments above fully demonstrate the application value and practicality of the method of the present invention in the evaluation of the sealing performance of nuclear power plant gates and the formulation of maintenance plans.

[0095] Figure 1 This is a schematic diagram illustrating the steps of an embodiment of this application. The leakage rate calculation of this structure includes the following steps:

[0096] Step S1: Simulate the mechanical deformation characteristics of the gate O-ring under thermo-mechanical coupling conditions.

[0097] Under nuclear power plant accident conditions, sealing materials are subjected to the combined effects of temperature, medium pressure, compressibility, and contact surfaces, leading to rubber aging and changes in mechanical properties. Therefore, the contact stress of the seal is an important indicator of changes in the performance of the sealing material.

[0098] 1.1 Reference contact stress S of O-ring under thermo-coupling conditions Gr With compression ratio C i The relationship.

[0099] This embodiment considers the combined effects of temperature and stress. In this embodiment, the following parameters are considered: the O-ring wire diameter is d, the inner diameter is D, and the compression ratio is C. i Finite element analysis model such as Figure 2 As shown.

[0100] like Figure 3 As shown, the mechanical analysis includes three steps: contact, compression, and heating. In the contact step, the upper and lower rigid body surfaces are combined with the rubber model to establish the contact state; in the compression step, the upper flange is controlled to achieve a compression ratio of the set value C. i The model's temperature is increased to the aging temperature T during the heating step by applying boundary conditions. The contact stress obtained at this point is denoted as the initial contact stress S. G0 .

[0101] Select reference temperature T r At the simulated reference temperature, different C iThe initial contact stress S of the O-ring corresponding to the condition G0 And denote it as the reference contact stress S Gr .like Figure 4 S was shown Gr With C i The relationship is as follows. Based on the calculated values, the fitting relationship is:

[0102] S Gr =α r +β r C i 1)

[0103] Where α r and β r The fitting coefficients are to be determined. In this embodiment, α r =0.30542 and β r =0.2064

[0104] 1.2 Initial contact stress S of O-ring under thermo-coupling conditions G0 Relationship with temperature T

[0105] By changing the compression ratio, the initial contact stress values ​​at different temperatures T are calculated, in S Gr Use the value as a reference for a given compression ratio C i S below G0 Dimensionless transformation yields S G0 / S Gr like Figure 5 The scatter plot is shown. It can be seen that C i For S G0 / S Gr The impact is negligible, therefore a unified S can be established based on the obtained data. G0 / S Gr Function of temperature T:

[0106] S G0 / S Gr =α0+β0T 2)

[0107] Where α0 and β0 are the fitting coefficients to be determined. In this embodiment, α0 = 0.92903 and β0 = 0.00175.

[0108] Based on equations (1) and (2), S can be established. G0 With C i The relationship between T and T is:

[0109] S G0 =(S G0 / S Gr )×S Gr = (α0 + β0T) × (α r +β r Ci ) 3)

[0110] Step S2: Based on aging data, perform finite element analysis on the long-term relaxation characteristics of the gate O-ring under thermo-coupling conditions.

[0111] For O-rings, the relaxation characteristics mainly affect the contact stress, which decreases with increasing relaxation time, and the rate of decrease varies at different temperatures. The key step in this process is to establish a quantitative relationship between temperature and time and the contact stress through macroscopic finite element analysis of the O-ring contact.

[0112] 2.1 Long-term relaxation characteristics of gate O-rings under thermo-coupling conditions

[0113] Based on the stress relaxation test measurement data of rubber materials, the generalized Maxwell model is characterized by Prony series to obtain the viscoelastic parameters of the rubber materials, which are then applied to the simulation analysis of rubber relaxation characteristics. Figure 6 This is a schematic diagram illustrating the analysis steps for the long-term relaxation characteristics in this embodiment. Figure 3 After the mechanical analysis is completed, a relaxation step can be added to simulate the long-term mechanical properties. This embodiment uses a compression ratio of 25% as an example, and based on the relaxation process simulation, the contact stress S corresponding to different relaxation times τ is obtained. G ,like Figure 7 As shown.

[0114] 2.2 Contact stress S of gate O-ring under thermo-coupling conditions G Relationship between aging temperature T and relaxation time τ

[0115] In this embodiment, S is established based on the aging kinetic equation and the Arrhenius equation. G / S G0 = f(T,τ) function. The Arrhenius equation is:

[0116] k = Ae -E / RT (4)

[0117] Where T is temperature; A is a constant independent of both temperature and time; E and R are the activation energy and molar gas constant, respectively. k is the reaction rate constant.

[0118] The aging kinetic equation takes the following form:

[0119]

[0120] In the above formula, f = S G / S G0 In the formula, B0 and α are constants independent of temperature, and τ is time.

[0121] Combining the two equations above, we get the following equation:

[0122]

[0123] In the formula, B1=αln(A), B2=-αE / R, B3=α.

[0124] In summary, the coefficients B0, B1, B2, and B3 are all independent of the independent variables temperature T and aging time τ. The undetermined coefficients in the above formula were obtained by fitting the calculated data. In this embodiment, B0 = 4.551083, B1 = -0.047785, B2 = 496.510752, B3 = 0.818283.

[0125] Changing the temperature, different τ values ​​were obtained for S G / S G0 The result is as follows Figure 8 The scatter plots are shown in the figure. Based on the scatter plots, S is established in the form of equation (6). G / S G0 The relationship between temperature T and time τ is used to obtain regression coefficients B0, B1, B2, and B3, and the expression is established as shown in equation (7). A plot is then created. Figure 8 The curve in the image.

[0126]

[0127] Combining equations (3) and (7) yields the contact stress S. G The formula for calculating C. Based on this formula, any C can be calculated. i The contact stress S corresponding to T and τ G Its specific form is:

[0128]

[0129] Step S3: Through micro-contact finite element analysis of the sealed structure, establish the relationship between the actual height h of the rough channel and the average contact stress S. G The quantitative relationship between them.

[0130] When the O-ring contacts the flange, the roughness of the contact surface during machining creates meandering flow channels at the sealing interface. The sealing force reduces the height of these channels by compressing and deforming the sealing material. The relationship between the sealing force and the channel height h needs to be analyzed using the micro-contact characteristics of rough surfaces. 3.1 Establishing a micro-contact analysis model for rough surfaces.

[0131] Machined surfaces can be considered as Gaussian rough surfaces. Therefore, after measuring the surface microstructure, the surface parameters of the Gaussian rough surface—roughness σ and autocorrelation scale A—can be obtained based on the measurement data or known machining parameters. TTo establish the relationship between h and contact stress S G To determine the quantitative relationship between the peaks, this embodiment approximates the micro-roughness peaks as hemispheres with uniform radii (radius equal to the statistical roughness 3σ) based on the micro-contact theory of rough surfaces. Following the statistical roughness surface analysis method, a 3×3 roughness peak array is selected, with an interval equal to the roughness surface autocorrelation scale A. T (See Figure 9 ).

[0132] 3.2 Calculate the contact interface separation height h corresponding to different contact pressures.

[0133] In this embodiment, the micro-indentation depth of the rough hemispherical array in the rubber material under different contact stresses is calculated by simulating the micro-indentation test process. The key point of this step is to substitute the effect of rubber material aging into the O-ring constitutive model. In this embodiment, as... Figure 10 As shown, h0 is the nominal interface gap height when the contact stress is 0. Microscopic contact analysis can obtain the contact indentation depth δ of the rigid rough peak under a certain compressive force F; and according to h=h0-δ, the data of h can be easily obtained.

[0134] 3.3 Establish the functional relationship between the contact gap height and the contact stress.

[0135] Hertz's elastic contact theory gives the relationship between h and contact stress S. G The functional form between them. Define the dimensionless gap height h. * =h / h0, and dimensionless stress S G * =S G / E. In this embodiment, h was verified. * and S G * The relationship between the elastic modulus and the roughness peak height is independent of the elastic modulus and the roughness peak height. Therefore, the h value fitted by the roughness peak matrix microindentation test is... * and S G * The relationship is as follows:

[0136]

[0137] The relationship between the calculated points and the fitted formula obtained for different roughnesses is as follows: Figure 11 As shown. In this embodiment, a h =0.99229,b h =1.25309,c h =0.64259.

[0138] Step S4: Establish a leakage rate calculation model based on leakage channel flow analysis.

[0139] The magnitude of interface leakage is related to the roughness characteristics of the contact surface (roughness σ and autocorrelation length A). T The flow characteristics of the medium in the rough interface gap are related to factors such as the contact state (gap height h), the internal and external pressure difference, and the flow properties of the medium. The key point of this step is to select appropriate modeling and solution methods to determine the influence of these parameters on the flow behavior of the medium in the rough interface gap. In this embodiment, the micropore space of the contact interface is established based on rough surface numerical reconstruction technology, and the flow of fluid in the micropore space formed at the contact interface is simulated using lattice Boltzmann mesoscopic numerical simulation technology. This part specifically includes the following steps:

[0140] 4.1 Establish a flow analysis model for the gap between contact surfaces.

[0141] In this embodiment, after statistical analysis of the measured rough surface, the roughness σ and autocorrelation scale A are obtained. T The random rough surface is regenerated using numerical techniques. In this embodiment, to ensure the extrapolation of the leakage rate calculation formula, different statistical parameters are used to construct multiple rough surfaces. The model is established as follows: Figure 12 As shown.

[0142] 4.2 Flow simulation of rough leakage channels.

[0143] Based on the leakage mechanism, numerical simulations were performed on the interfacial leakage flow with height h0 formed by surfaces with different roughness characteristics. This was achieved through Φ... σ =Q0 / Q p Characterizing the effect of roughness on flow, it can be seen that Φ σ It is a dimensionless roughness σ* (σ*=σ / A) T A single-valued function can have its functional relationship obtained through numerical calculation. In this embodiment, such as... Figure 13 As shown, the fitting calculation results are as follows:

[0144]

[0145] In this embodiment, A σ =1.02876,B σ = -1.67792.

[0146] Based on the leakage mechanism, numerical simulations were performed on the interfacial leakage flow at different separation heights h on surfaces with the same roughness. This was achieved using Φ... h =Q / Q0 characterizes the effect of the gap height variation on the flow in the rough leakage channel, and it can be seen that Φ h It is the dimensionless height h * (h * A single-valued function (=h / h0) can have its functional relationship obtained through numerical calculation. In this embodiment, as... Figure 14 As shown, the fitting is based on the calculation results:

[0147] Q / Q0 = A h exp(B h ·h * (11)

[0148] In this embodiment, A h =0.03021,B h =3.556.

[0149] 4.3 Formula for calculating leakage rate at sealing interface

[0150] Based on the established gap flow analysis model, the flow state of the leaking medium is simulated. In this implementation example, the contact area can be considered as a ring, the width of the leakage channel (average circumference of the O-ring) is L, and the channel length (contact width) is B, as follows. Figure 15 As shown. With the internal and external pressures of the medium being p1 and p2 respectively, the medium viscosity coefficient being μ, and the initial channel height being h0, the expression for the leakage rate based on Poiseuille's cubic flow formula is:

[0151]

[0152] Based on the above analysis, the specific form of the leakage rate established in this embodiment is as follows:

[0153]

[0154] This expression is universal and, combined with the previous micro-contact mechanics analysis via the gap height h, is applicable to the calculation of leakage on Gaussian random rough surfaces with known roughness characteristics.

[0155] Step S5: Analysis of influencing factors and evaluation of long-term sealing performance

[0156] Combining steps S1 to S4, the leakage rate under various aging conditions can be predicted. When the maximum allowable leakage rate Q... lim Given a given aging state, it is possible to evaluate whether the gate meets safety requirements. In this embodiment, the leakage rate at different times is calculated as follows: Figure 16 As shown, Q lim The following leakage rates are all acceptable.

[0157] Select different temperatures T1, T2, T3, T4, and T5, determine other parameters, and calculate the O-ring leakage rate at different times.

[0158] Select different medium pressures P1, P2, P3, P4, and P5, determine other parameters, and calculate the O-ring leakage rate at different times.

[0159] Choose different compression ratios C i1 C i2C i3 Once other parameters are determined, the O-ring leakage rate at different times is calculated.

[0160] like Figure 1 As shown in the embodiment of the present invention, the method for predicting the time-related leakage rate of the O-ring of a nuclear power plant valve includes:

[0161] S1. Establish a finite element model of the gate O-ring under thermo-coupling conditions and analyze the mechanical properties of the O-ring; based on the initial conditions (compression ratio C)... i Calculate the contact width and initial contact stress corresponding to different compression ratios and temperatures (T, T); observe the patterns in the simulation data, and adjust the initial contact stress S based on various factors. G0 The influence patterns were established separately for S. G0 / S Gr =g1(T) and S Gr =g2(C i ), where S Gr The initial contact stress at the reference temperature; denoted as S G0 =(S G0 / S Gr )×S Gr The initial contact stress S under thermo-coupling conditions is established in the form of... G0 With compression ratio C i Relationship with temperature T: S G0 =f(C i ,T);

[0162] S2, a finite element method is established for the long-term relaxation analysis of the gate O-ring under thermo-coupling conditions, simulating the long-term relaxation characteristics of the O-ring under thermo-coupling conditions; the contact stress S of the O-ring under different compression ratios and aging temperatures is output. G Curve showing the change over time; definition of dimensionless contact stress S G / S G0 , with S G / S G0 To determine the long-term performance indicators of the sealing ring, based on the aging kinetic model and Aronus's formula, and using numerical simulation results, a dimensionless contact stress S for the gate seal is established. G / S G0 -Temperature T-Time τ Relationship: S G / S G0 =f(T,τ);

[0163] S3, based on numerical analysis of microscopic contact mechanics of rough interfaces, establishes the contact stress S G The quantitative relationship between the separation height h from the sealing interface and the following: h = f(S) G );

[0164] S4. Based on numerical reconstruction of rough surfaces and numerical simulation of interfacial leakage flow characteristics, the relationship between leakage rate Q and sealing surface roughness parameters σ and A is established. T The quantitative relationship between sealing medium pressure P, sealing interface contact width B, and sealing interface separation height h is: Q = f(B, P, σ, A) T ,h);

[0165] By combining S5 with S1 to S4, we can obtain the variation law of the leakage rate Q of a given sealing structure with respect to compression ratio, temperature, and time, that is: Q = f(C i ,T,τ);

[0166] S6 Influencing Factors Analysis and Sealing Performance Evaluation: Given operating parameters (temperature T, medium pressure P, compressibility C) i Using the allowable leakage rate of the containment gate as a safety criterion, and the service time τ, the long-term sealing performance of the gate under thermal coupling conditions is evaluated.

[0167] S1 simulates the mechanical properties of the O-ring under thermo-coupling conditions and establishes the functional relationship of the initial contact stress, specifically including the following steps:

[0168] S101, Set the reference aging temperature T r Establish T r Initial contact stress S Gr With compression ratio C i Relationship: S Gr =f(C i The specific method is as follows:

[0169] (1) Establish a finite element analysis model of the sealing structure; (2) Select an appropriate constitutive equation to describe the hyperelastic properties of the rubber; (3) Input the thermophysical parameters of the sealing material; (4) Apply a displacement load to achieve the set compression ratio C. i (5) By setting the temperature boundary T r Simulate the environment at the reference aging temperature; (6) Obtain S Gr (7) Change the compression ratio, repeat the calculation, and obtain another S. Gr (8) Through multiple sets of calculations, fit S Gr Regarding C i Function: S Gr =g1(C i );

[0170] S102, Set compression ratio C i To obtain the S of the O-ring at a set compression rate G0 / S GrThe relationship with different aging temperatures T is as follows: (1) Change the aging temperature T and repeat the same finite element analysis as in the previous step to obtain the initial contact stress S of the O-ring at different aging temperatures. G0 (2) With the same compression ratio C i The reference temperature T r The corresponding initial contact stress S Gr As a characteristic quantity, the initial contact stress S at multiple temperatures is... G0 Dimensionless, i.e., S G0 / S Gr (3) Establish S G0 / S Gr A function of aging temperature T: S G0 / S Gr =g2(T);

[0171] S103. Establish the initial contact stress S under thermo-coupling conditions. G0 With compression ratio C i Relationship with temperature T: S G0 =f(C i The specific method is as follows: (1) Change the compression ratio C i Repeat step S102 to obtain multiple sets of compression ratios C. i S below G0 / S Gr Data corresponding to different aging temperatures T; (2) Observing the numerical calculation results, it can be found that the compression ratio C i For S G0 / S Gr The effect of S on the functional relationship with temperature T is very weak, therefore S can be considered as... G0 / S Gr S is a single-valued function of temperature T, i.e.: G0 / S Gr =g2(T); (3) with S G0 =(S G0 / S Gr )×S Gr In the form of S, we obtain S G0 With C i The relationship between S and T: G0 =f(C i ,T).

[0172] S2 simulates the long-term relaxation characteristics of the O-ring under thermo-coupling conditions and establishes a functional relationship describing the long-term change of the O-ring contact stress over time under thermo-coupling conditions. The specific steps include:

[0173] S201. Based on the finite element simulation method, simulate the stress relaxation characteristics of O-rings under thermo-coupling conditions. The specific method is as follows: (1) Add a relaxation step after the finite element analysis step in S1 and set the relaxation time τ; (2) Based on the stress relaxation test measurement data of rubber materials, establish a generalized Maxwell model describing the viscoelastic properties of rubber; (3) Based on the simulation of the relaxation process, obtain the contact stress S corresponding to different relaxation times τ. G (4) Plot the compression ratio C at different rates i S corresponding to aging temperature T G -τ curve.

[0174] S202. Observe the effects of various factors on S G -τ curve, establishing contact stress S G Regarding the relationship between aging temperature T and relaxation time τ, the specific method is as follows: (1) Define the dimensionless contact stress S G / S G0 S G0 The initial contact stress corresponding to the same compression ratio and the same aging temperature; dimensionless contact stress can indicate the degradation characteristics of the sealing performance of rubber O-rings under stress and aging temperature; (2) with S G / S G0 As an aging index, S is established using the aging kinetic equation and the Aronius formula. G / S G0 (3) The numerical results are organized into different compression ratios C. i S under different aging temperatures T and different aging times τ G / S G0 (4) Substitute the numerical solution into S G / S G0 The function of aging temperature T and aging time τ is used to solve for the correlation coefficient in the function and establish S. G / S G0 The specific expressions for temperature T and time τ: S G / S G0 =f(T,τ);

[0175] S203, the S obtained from S1 is... G0 =f(C i ,T) and S G / S G0 By combining f(T,τ), we can obtain S under thermo-mechanical coupling. G Calculation formula:

[0176] S3 is used to establish a microscopic contact mechanics model for the micro-roughness peak. Finite element analysis is used to establish the relationship between the sealing surface separation height h and the average contact stress S. GThe functional relationship between them includes the following steps:

[0177] S301. Based on the measurement of the micro-morphology of the sealing surface or the machining parameters, establish a micro-contact analysis model for the rough surface;

[0178] S302. Through finite element analysis of the micro-contact process on rough surfaces, the average contact stress S is established. G The correspondence between the separation height h of the contact interface (effective height of the leakage channel);

[0179] S303, Hertz elastic contact theory gives S G The function form between h and [the other element] is used. Substituting the numerical results, the formula for calculating the separation height of the rubber O-ring sealing interface can be established: h = f(S). G ).

[0180] S4 is a flow analysis of the leakage channel at the sealing interface under thermo-coupling conditions, which includes the following steps:

[0181] S401. Based on the surface micromorphology parameters obtained in S3, a three-dimensional numerical rough surface is established, which forms a sealing interface leakage channel with a smooth surface having a certain separation distance h.

[0182] S402. Set the sealing interface separation height h0 when the average contact stress is 0, which depends only on the sealing surface roughness σ; set the sealing interface separation height h under a certain average contact stress, which is related to the contact stress S. G The relationship depends on the results of the micro-contact mechanics analysis of the S3 rough interface;

[0183] S403. Using a mesoscopic analysis model of the leakage channel flow, numerical simulations were performed on the interfacial leakage flow with height h0 composed of surfaces with different roughness characteristics. The influence of surface roughness on the flow characteristics of the sealing interface was obtained, and a functional relationship of the following form was established: Q0 / Q p =f(σ,A) T Among them, the average roughness σ and the autocorrelation length A T Q is one of two statistical parameters reflecting surface roughness characteristics. p To determine the leakage rate of a leakage channel consisting of two smooth surfaces with a separation height of h0; Q0 / Q p The roughness factor Φ is defined as the leakage rate. σ Then we have: Φ σ =Q0 / Q p =f(σ,A) T );

[0184] S404. Using a mesoscopic analysis model of the leakage channel flow, numerical simulations are performed on the interfacial leakage flow with different separation heights h, formed by surfaces with the same roughness characteristics. The influence of the separation height on the flow characteristics of the sealing interface is obtained, and a functional relationship of the following form is established: Q / Q0=f(h); where Q0 is the leakage rate of a leakage channel with a separation height of h0 (the channel height corresponding to zero contact stress) formed by a given roughness surface; Q / Q0 is defined as the height factor Φ of the leakage rate. h Establish Φ based on numerical results h The functional relationship between the contact height h and the contact height is: Q = Q / Q0 = f(h);

[0185] S405. Establish the formula for calculating the leakage rate of the sealing interface: Q = Φ σ ×Φ h ×Q p Q p This is the leakage rate of a leakage channel with a height of h0 (the channel height corresponding to zero contact stress) formed by a smooth surface; this formula can be extended from the mesoscopic to the macroscopic; for O-rings, Q p Poiseuille's law, which describes the flow between parallel plates, can be used for calculation. In this case, the geometric dimensions of the leakage channel are the O-ring contact width B and the average circumference L, and the pressure difference is the pressure difference P between the inside and outside of the O-ring. Finally, we can obtain: Q = f(B, P, σ, A) T ,h).

[0186] like Figure 17 As shown in the embodiment of the present invention, the nuclear power plant gate O-ring time-related leakage rate prediction system includes:

[0187] The finite element model building module is used to build a finite element model of a gate O-ring under thermo-coupling conditions and analyze the mechanical properties of the O-ring; based on initial conditions (compression ratio C)... i Calculate the contact width and initial contact stress corresponding to different compression ratios and temperatures (T, T); observe the patterns in the simulation data, and adjust the initial contact stress S based on various factors. G0 The influence patterns were established separately for S. G0 / S Gr =g1(T) and S Gr =g2(C i ), where S Gr The initial contact stress at the reference temperature; denoted as S G0 =(S G0 / S Gr )×S Gr The initial contact stress S under thermo-coupling conditions is established in the form of... G0 With compression ratio C i Relationship with temperature T: S G0 =f(Ci ,T);

[0188] The finite element method (FEM) module is used to establish a FEM for long-term relaxation analysis of gate O-rings under thermo-coupling conditions, simulating the long-term relaxation characteristics of O-rings under thermo-coupling conditions; it outputs the O-ring contact stress S under different compression ratios and aging temperatures. G Curve showing the change over time; definition of dimensionless contact stress S G / S G0 , with S G / S G0 To determine the long-term performance indicators of the sealing ring, based on the aging kinetic model and Aronus's formula, and using numerical simulation results, a dimensionless contact stress S for the gate seal is established. G / S G0 -Temperature T-Time τ Relationship: S G / S G0 =f(T,τ);

[0189] The contact mechanics numerical analysis module is used for numerical analysis of microscopic contact mechanics based on rough interfaces, and to establish the contact stress S. G The quantitative relationship between the separation height h from the sealing interface and the following: h = f(S) G );

[0190] The flow characteristic numerical simulation module is used for numerical reconstruction of flow characteristics based on rough surfaces and interface leakage, establishing the relationship between leakage rate Q and the roughness parameters σ and A of the sealing surface. T The quantitative relationship between sealing medium pressure P, sealing interface contact width B, and sealing interface separation height h is: Q = f(B, P, σ, A) T ,h);

[0191] The variation law acquisition module is used to obtain the variation law of the leakage rate Q of a given sealing structure with respect to compression ratio, temperature and time, that is: Q=f(C i ,T,τ);

[0192] Influencing Factor Analysis and Sealing Performance Evaluation Module: Used for given operating parameters (temperature T, medium pressure P, compressibility C) i Using the allowable leakage rate of the containment gate as a safety criterion, and the service time τ, the long-term sealing performance of the gate under thermal coupling conditions is evaluated.

[0193] An application embodiment of the present invention provides a computer device, which includes a memory and a processor. The memory stores a computer program, and when the computer program is executed by the processor, the processor performs the steps of a method for predicting the time-related leakage rate of a nuclear power plant gate O-ring.

[0194] An application embodiment of the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of a method for predicting the time-related leakage rate of a nuclear power plant gate O-ring.

[0195] An application embodiment of the present invention provides an information data processing terminal, which is used to implement a nuclear power plant gate O-ring time-related leakage rate prediction system.

[0196] At compression ratio C i When the pressure is 25%, in order to ensure that the O-ring's normal operating time (life) reaches τ = 365 days, calculate the maximum temperature T corresponding to different medium pressures P.

[0197] The initial contact stress is obtained according to equation (3):

[0198] S G0 = (α1+β1T)×(α2+β2C) i )

[0199] = (0.92903 + 0.00175 × 80) × (0.30542 + 0.2064 × 25)

[0200] =5.8427MPa

[0201] When the running time τ = 365 days, according to equation (8), we can obtain

[0202]

[0203] The elastic modulus of the material used was measured to be E = 10.05782 MPa. According to equation (9), the dimensionless gap height h can be obtained. * =h / h0, which is:

[0204]

[0205] The characteristic parameters of rough surfaces include σ = 1 μm and A. T =0.08μm, which yields the dimensionless roughness σ * =σ / A T =1 / 0.08=12.5. According to equation (10):

[0206]

[0207] According to equation (11), we get:

[0208] Φ h =Q / Q0=A h exp(B h ·h * )

[0209] =0.03021exp(3.556×0.2818)

[0210] =0.0823

[0211] Choose P = 0.7 MPa, atmospheric pressure is P b Taking a pressure of 0.1 MPa as an example, the finite element analysis results show that the flow channel length (contact width) B = 0.006999 m, the leakage channel width (average circumference of the O-ring) L = 0.6283 m, and the initial leakage channel height h0 = 3σ. At T = 80℃, the calculated dynamic viscosity of the medium is μ = 2.0306 × 10⁻⁶. -5 Pa·s, density ρ=6.67554kg / m³ 3 At this time, we get

[0212]

[0213] Therefore, according to equation (13), the leakage rate Q of the sealing structure under this working condition is obtained as:

[0214]

[0215] According to nuclear power safety standards, the maximum permissible leakage rate Q is... lim =4.1229×10 -8 kg / s. Therefore, based on the safety criterion, Q = 2.7826 × 10⁻⁶ kg / s. -8 ≤4.1229×10 -8 =Q lim This indicates that the O-ring is still in normal service and within its lifespan, therefore the temperature can continue to rise.

[0216] By setting a certain temperature step and gradually increasing the temperature, repeating the above steps, the leakage rate corresponding to different temperatures T was calculated. It was finally found that when T = 92.5℃, the leakage rate Q = 4.1758 × 10⁻⁶. -8 kg / s, does not meet the safety criterion Q≤Q lim The temperature at this point is recorded as the maximum temperature (failure temperature) T that can be applied to ensure the O-ring operates for 365 days under a medium pressure P = 0.7 MPa. max .

[0217] Similarly, by changing the initial conditions and selecting different medium pressures P or the desired normal operating time (life) τ of the O-ring, different maximum temperatures (failure temperatures) can be obtained.

[0218] According to the method in the application embodiment, the relationship between different medium pressures and the maximum temperature (failure temperature) at a compression ratio of 25% can be obtained. Based on this relationship, a seal safety boundary map can be plotted. Taking the curve at a compression ratio of 25% as an example, it divides the considered temperature-pressure diagram into two parts. The left side of the curve indicates that the leakage rate is less than the limit leakage rate, and therefore represents the safe region. The right side of the curve represents the region where the leakage rate is greater than the limit leakage rate, and is considered the leakage region. Based on the curves in the figure, the failure temperature corresponding to the medium pressure can be easily found.

[0219] The sealing safety boundary map generated using this method can clearly and quickly assist in determining the sealing state of the gate O-ring under a given operating condition, eliminating the need for complex measurement processes or even shutdown experiments. Furthermore, during the design process of the sealing structure, this map can guide parameter design and determine the most extreme operating conditions under which the entire sealing structure can operate normally.

[0220] It should be noted that embodiments of the present invention can be implemented in hardware, software, or a combination of both. The hardware portion can be implemented using dedicated logic; the software portion can be stored in memory and executed by a suitable instruction execution system, such as a microprocessor or dedicated-design hardware. Those skilled in the art will understand that the above-described devices and methods can be implemented using computer-executable instructions and / or included in processor control code, for example, such code provided on a carrier medium such as a disk, CD, or DVD-ROM, a programmable memory such as read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The devices and modules of the present invention can be implemented by hardware circuitry such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, or programmable hardware devices such as field-programmable gate arrays, programmable logic devices, etc., or by software executed by various types of processors, or by a combination of the above-described hardware circuitry and software, such as firmware.

[0221] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for predicting the time-related leakage rate of a nuclear power plant valve O-ring, characterized in that, include: S1. Establish a finite element model of the gate O-ring under thermo-coupling conditions and analyze the mechanical properties of the O-ring; Based on the initial conditions, calculate the contact width and initial contact stress corresponding to different compression ratios and temperatures; Based on various factors, the initial contact stress S G0 The influence patterns were established separately for S. G0 / S Gr = g1(T) and S Gr = g2(C i ), where S Gr The initial contact stress is at the reference temperature; With S G0 = (S G0 / S Gr )×S Gr The initial contact stress S under thermo-coupling conditions is established in the form of... G0 With compression ratio C i Relationship with temperature T: S G0 = f(C i , T); S2, a finite element method is established for the long-term relaxation analysis of the gate O-ring under thermo-coupling conditions, simulating the long-term relaxation characteristics of the O-ring under thermo-coupling conditions; the contact stress S of the O-ring under different compression ratios and aging temperatures is output. G Curve showing the change over time; definition of dimensionless contact stress S G / S G0 , with S G / S G0 To determine the long-term performance indicators of the sealing ring, based on the aging kinetic model and Aronus's formula, and using numerical simulation results, a dimensionless contact stress S for the gate seal is established. G / S G0 -Temperature T-Time τ Relationship: S G / S G0 = f(T, τ); S3, based on numerical analysis of microscopic contact mechanics of rough interfaces, establishes the contact stress S G Quantitative relationship of the separation height h from the sealing interface: h = f(S) G ); S4. Based on numerical reconstruction of rough surfaces and numerical simulation of interfacial leakage flow characteristics, the relationship between leakage rate Q and sealing surface roughness parameters σ and A is established. T The quantitative relationship between sealing medium pressure P, sealing interface contact width B, and sealing interface separation height h is: Q = f(B, P, σ, A) T , h); By combining S5 with S1~S4, we can obtain the variation law of the leakage rate Q of a given sealing structure with respect to compression ratio, temperature, and time, that is: Q = f(C i , T, τ); S6 Influencing Factor Analysis and Sealing Performance Evaluation: Given operating parameters, the long-term sealing performance of the gate under thermo-coupling conditions is evaluated based on the allowable leakage rate of the containment gate as a safety criterion.

2. The method for predicting the time-related leakage rate of a nuclear power plant gate O-ring as described in claim 1, characterized in that, S1 simulates the mechanical properties of the O-ring under thermo-coupling conditions and establishes the functional relationship of the initial contact stress, specifically including the following steps: S101, Set the reference aging temperature T r Establish T r Initial contact stress S Gr With compression ratio C i Relationship: S Gr = f(C i The specific method is as follows: (1) Establish a finite element analysis model of the sealing structure; (2) Select an appropriate constitutive equation to describe the hyperelastic properties of the rubber; (3) Input the thermophysical parameters of the sealing material; (4) Apply a displacement load to achieve the set compression ratio C. i (5) By setting the temperature boundary T r Simulate the environment at the reference aging temperature; (6) Obtain S Gr (7) Change the compression ratio, repeat the calculation, and obtain another S. Gr (8) Through multiple sets of calculations, fit S Gr Regarding C i Function: S Gr = g1(C i ); S102, Set compression ratio C i To obtain the S of the O-ring at a set compression rate G0 / S Gr The relationship with different aging temperatures T is as follows: (1) Change the aging temperature T and repeat the same finite element analysis as in the previous step to obtain the initial contact stress S of the O-ring at different aging temperatures. G0 (2) With the same compression ratio C i The reference temperature T r The corresponding initial contact stress S Gr As a characteristic quantity, the initial contact stress S at multiple temperatures is... G0 Dimensionless, i.e., S G0 / S Gr (3) Establish S G0 / S Gr A function of aging temperature T: S G0 / S Gr = g2 (T); S103. Establish the initial contact stress S under thermo-coupling conditions. G0 With compression ratio C i Relationship with temperature T: S G0 = f(C i The specific method is as follows: (1) Change the compression ratio C i Repeat step S102 to obtain multiple sets of compression ratios C. i S below G0 / S Gr Data corresponding to different aging temperatures T; (2) S G0 / S Gr As a single-valued function of temperature T, i.e.: S G0 / S Gr = g2(T); (3) with S G0 =(S G0 / S Gr )×S Gr In the form of S, we obtain S G0 With C i The relationship between S and T: G0 = f(C i , T).

3. The method for predicting the time-related leakage rate of a nuclear power plant gate O-ring as described in claim 1, characterized in that, S2 simulates the long-term relaxation characteristics of the O-ring under thermo-coupling conditions and establishes a functional relationship describing the long-term change of the O-ring contact stress over time under thermo-coupling conditions. The specific steps include: S201. Based on the finite element simulation method, the stress relaxation characteristics of the O-ring under thermo-coupling conditions are simulated. The specific method is as follows: (1) Add a relaxation step after the finite element analysis step in S1 and set the relaxation time τ; (2) Based on the stress relaxation test measurement data of rubber materials, establish a generalized Maxwell model describing the viscoelastic properties of rubber; (3) Based on the simulation of the relaxation process, obtain the contact stress S corresponding to different relaxation times τ. G (4) Plot the compression ratio C at different rates i S corresponding to aging temperature T G -τ curve; S202. Observe the effects of various factors on S G -τ curve, establishing contact stress S G Regarding the relationship between aging temperature T and relaxation time τ; S203, the S obtained from S1 G0 = f(C i , T) and S G / S G0 By combining f(T, τ) with the thermo-mechanical coupling, S can be obtained. G Calculation formula: .

4. The method for predicting the time-related leakage rate of the O-ring of a nuclear power plant valve as described in claim 3, characterized in that, S202. Observe the effect of various factors on the SG-τ curve, and establish the relationship between contact stress SG and aging temperature T and relaxation time τ. The specific method is as follows: (1) Define dimensionless contact stress SG / SG0, where SG0 is the initial contact stress corresponding to the same compression ratio and the same aging temperature; dimensionless contact stress can indicate the degradation characteristics of the sealing performance of rubber O-rings under stress and aging temperature. (2) Using SG / SG0 as the aging index, the functional form of SG / SG0 with aging temperature T and aging time τ is established through the aging kinetic equation and Aronus formula; (3) The numerical results are organized into SG / SG0 under different compression ratios Ci, different aging temperatures T and different aging times τ; (4) Substitute the numerical solution into the function of SG / SG0 with aging temperature T and aging time τ, solve the correlation coefficient in the function, and establish the specific expression of SG / SG0 with respect to temperature T and time τ: SG / SG0 = f(T, τ).

5. The method for predicting the time-related leakage rate of a nuclear power plant gate O-ring as described in claim 1, characterized in that, S3 is used to establish a microscopic contact mechanics model for the micro-roughness peak. Finite element analysis is used to establish the relationship between the separation height h of the sealing surface and the average contact stress S. G The functional relationship between them includes the following steps: S301. Based on the measurement of the micro-morphology of the sealing surface or the machining parameters, establish a micro-contact analysis model for the rough surface; S302. Through finite element analysis of the micro-contact process on rough surfaces, the average contact stress S is established. G The correspondence between the separation height h of the contact interface and the contact interface. S303, Hertz elastic contact theory gives S G By substituting the numerical results into the functional form of h, we can establish the formula for calculating the separation height of the rubber O-ring sealing interface: h = f(S) G ).

6. The method for predicting the time-related leakage rate of a nuclear power plant gate O-ring as described in claim 1, characterized in that, S4 is a flow analysis of the leakage channel at the sealing interface under thermo-coupling conditions, which includes the following steps: S401. Based on the surface micromorphology parameters obtained in S3, a three-dimensional numerical rough surface is established, which forms a sealing interface leakage channel with a smooth surface having a certain separation distance h. S402. Set the sealing interface separation height as h0 when the average contact stress is 0, which depends only on the sealing surface roughness σ; set the sealing interface separation height as h under a certain average contact stress, which is related to the contact stress S. G The relationship depends on the results of the micro-contact mechanics analysis of the S3 rough interface; S403. Using a mesoscopic analysis model of the leakage channel flow, numerical simulations were performed on the interfacial leakage flow with height h0 composed of surfaces with different roughness characteristics. The influence of surface roughness on the flow characteristics of the sealing interface was obtained, and a functional relationship of the following form was established: Q0 / Q p = f(σ, A T ); where the average roughness σ and the autocorrelation length A T Q is one of two statistical parameters reflecting surface roughness characteristics. p To determine the leakage rate of a leakage channel consisting of two smooth surfaces with a separation height of h0; Q0 / Q p The roughness factor Φ is defined as the leakage rate. σ Then we have: Φ σ =Q0 / Q p = f(σ, A T ); S404. Using a mesoscopic analysis model of the leakage channel flow, numerical simulations are performed on the interfacial leakage flow with different separation heights h, formed by surfaces with the same roughness characteristics. The influence of the separation height on the flow characteristics of the sealing interface is obtained, and a functional relationship of the following form is established: Q / Q0 = f(h); where Q0 is the leakage rate of a leakage channel with a separation height of h0 formed by a given roughness surface; Q / Q0 is defined as the height factor Φ of the leakage rate. h Establish Φ based on numerical results h The functional relationship between the contact height h and the contact height is: Q = Q / Q0 = f(h); S405. Establish the formula for calculating the leakage rate of the sealing interface: Q=Φ σ ×Φ h ×Q p Q p Let Q be the leakage rate of a leakage channel of height h0 formed by a smooth surface; this formula can be extended from the mesoscopic to the macroscopic; for O-rings, Q p Poiseuille's law, which describes the flow between parallel plates, can be used for calculation. In this case, the geometry of the leakage channel is the O-ring contact width B and the average circumference L, and the pressure difference is the pressure difference P between the inside and outside of the O-ring. Finally, we can obtain: Q = f(B, P, σ, A) T , h).

7. A nuclear power plant valve O-ring time-related leakage rate prediction system applying the nuclear power plant valve O-ring time-related leakage rate prediction method as described in any one of claims 1 to 6, characterized in that, include: The finite element model building module is used to build a finite element model of a gate O-ring under thermo-coupling conditions and analyze the mechanical properties of the O-ring. Based on the initial conditions, calculate the contact width and initial contact stress corresponding to different compression ratios and temperatures; Observe the patterns in the simulation data and adjust the initial contact stress S based on various factors. G0 The influence patterns were established separately for S. G0 / S Gr = g1(T) and S Gr = g2(C i ), where S Gr The initial contact stress is at the reference temperature; With S G0 = (S G0 / S Gr )×S Gr The initial contact stress S under thermo-coupling conditions is established in the form of... G0 With compression ratio C i Relationship with temperature T: S G0 = f(C i , T); The finite element method establishment module is used to establish a finite element method for the long-term relaxation analysis of gate O-rings under thermo-coupling conditions, simulating the long-term relaxation characteristics of O-rings under thermo-coupling conditions. Output O-ring contact stress S under different compression ratios and aging temperatures G Curve showing the change over time; definition of dimensionless contact stress S G / S G0 , with S G / S G0 To determine the long-term performance indicators of the sealing ring, based on the aging kinetic model and Aronus's formula, and using numerical simulation results, a dimensionless contact stress S for the gate seal is established. G / S G0 -Temperature T-Time τ Relationship: S G / S G0 = f(T, τ); The contact mechanics numerical analysis module is used for numerical analysis of microscopic contact mechanics based on rough interfaces, and to establish the contact stress S. G Quantitative relationship of the separation height h from the sealing interface: h = f(S) G ); The flow characteristic numerical simulation module is used for numerical reconstruction of flow characteristics based on rough surfaces and interface leakage, establishing the relationship between leakage rate Q and the roughness parameters σ and A of the sealing surface. T The quantitative relationship between sealing medium pressure P, sealing interface contact width B, and sealing interface separation height h is: Q = f(B, P, σ, A) T , h); The variation law acquisition module is used to obtain the variation law of the leakage rate Q of a given sealing structure with respect to compression ratio, temperature, and time, that is: Q = f(C i , T, τ); Influencing Factor Analysis and Sealing Performance Evaluation Module: Used to evaluate the long-term sealing performance of the gate under thermal coupling conditions, given operating parameters and using the allowable leakage rate of the containment gate as a safety criterion.

8. A computer device comprising a memory and a processor, the memory storing a computer program, which, when executed by the processor, causes the processor to perform the steps of the nuclear power plant gate O-ring time-related leakage rate prediction method as described in any one of claims 1 to 5.

9. A computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of the nuclear power plant gate O-ring time-related leakage rate prediction method as described in any one of claims 1 to 5.

10. An information data processing terminal, used to implement the nuclear power plant gate O-ring time-related leakage rate prediction system as described in claim 7.

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