Method for calculating impact resistance of condenser

Abstract

The invention provides a condenser shock resistance calculation method which comprises the following steps: S1, establishing an equivalent simplified system of pipelines to obtain a plurality of equivalent pipelines; calculating the additional mass of liquid inside and outside each equivalent pipeline; carrying out fluid-structure interaction impact calculation; calculating the reference acceleration of each equivalent pipeline; applying the calculated reference acceleration of each equivalent pipeline to the single pipeline so as to analyze the response condition of the single pipeline under the impact load; the stress distribution of the single pipeline is obtained to evaluate the stability and safety of the single pipeline under the impact load; and comparing the effective stress of each order of modality and the modal stress synthesized by the modal synthesis method with allowable stress so as to carry out safety check. According to the method, a more accurate mathematical model and a physical model are adopted to describe the structure and the stress condition of the condenser, and the accuracy of a calculation result can be improved.

Description

Technical Field

[0001] The present application relates to the field of underwater anti-shock structures, and particularly to a method for calculating the anti-shock performance of a condenser. Background Art

[0002] During maritime confrontation operations, ships, as the main combat platforms, are mainly affected by the shock environment. The incompressibility of water and the pulsating effect of underwater bubbles make the impact on ships and equipment caused by non-contact underwater explosions at a long distance very serious. When the hull is damaged, according to the requirements of dynamic anti-sinking performance, its power equipment needs to remain intact to achieve the purpose of survival and even continue to carry out maritime combat missions. Therefore, the ability of shipborne equipment to cope with the anti-shock environment directly determines the combat effectiveness and vitality of the ship. In the design of ship equipment, it is of great practical significance to study its anti-shock ability.

[0003] To date, the power and parameters of ship power plants have been greatly improved, and the equipment structure has become increasingly complex. Marine condensers play a major role in ship steam power plants and have developed into large interconnected units with the improvement of technology, being more superior in structure and performance. As an important power device on ships, the strength analysis in the shock environment is extremely crucial for the vitality and combat effectiveness of the whole ship. However, there are still few relevant studies on its anti-shock calculation and dynamic simulation. Therefore, it is necessary to study the anti-shock performance calculation method to evaluate its anti-shock characteristics.

[0004] Existing methods for calculating the anti-shock performance of marine condensers still have some limitations and deficiencies, mainly reflected in the following aspects:

[0005] (1) Simplified model: Some methods may use overly simplified models to describe the structure and force conditions of the condenser, ignoring the complex situations that may be encountered in the actual working environment, resulting in insufficient accuracy of the calculation results;

[0006] (2) Incomplete parameters: The calculation method may not take into account all factors affecting the anti-shock performance of the condenser, such as material properties, structural design, environmental conditions, etc., resulting in limitations of the calculation results;

[0007] (3) Lack of standardization: There is currently no unified standardized calculation method. Different research units or enterprises may use different methods, resulting in insufficient comparability and reliability of the results;

[0008] (4) Long calculation time: Since some methods may rely on complex numerical simulations or computer models, the calculation process may consume a large amount of time and computing resources.

[0009] Therefore, the existing calculation methods for the shock resistance performance of condensers have certain drawbacks in terms of theoretical models, parameter consideration, standardization, and long calculation time, and further research and improvement are needed to improve their accuracy and reliability. Summary of the Invention

[0010] This application provides a method for calculating the shock resistance performance of a condenser, aiming to solve the problem of low accuracy in calculating the shock resistance performance of existing condensers.

[0011] The technical solution of this application is as follows:

[0012] A method for calculating the shock resistance performance of a condenser includes the following steps:

[0013] S1. Establish an equivalent simplified system of the pipeline to obtain multiple equivalent pipes;

[0014] S2. Calculate the additional mass of the liquid inside and outside each equivalent pipe;

[0015] S3. Conduct fluid-structure interaction shock calculation;

[0016] S4. Calculate the reference acceleration of each equivalent pipe;

[0017] S5. Apply the calculated reference acceleration of each equivalent pipe to a single pipe to analyze the response of the single pipe under the impact load;

[0018] S6. Obtain the stress distribution of the single pipe to evaluate the stability and safety of the single pipe under the impact load;

[0019] S7. Compare the effective stress of each order of mode and the modal stress synthesized by the modal synthesis method with the allowable stress to conduct a safety check.

[0020] As a technical solution of this application, in step S1, classify and segment the entire pipeline system according to the function, position, and material of the pipeline:

[0021] Determine the equivalent parameters of each pipe according to the characteristics and the environment of each pipe, and merge multiple similar pipes into equivalent pipes according to the equivalent parameters of the pipes;

[0022] Merge multiple similar connecting pipes into equivalent connecting pipes according to the number and position of the connecting pipes;

[0023] Verify the equivalent simplified system to make the characteristics of the equivalent simplified system match those of the original system;

[0024] Establish an equivalent model according to the equivalent simplified system.

[0025] As a technical solution of the present application, in step S2, calculate the mass of the liquid inside and outside the pipeline according to the density, volume, and flow velocity parameters of the liquid inside and outside the pipeline; evenly distribute the liquid mass inside and outside the pipeline, and add the liquid mass as additional mass to the equivalent model;

[0026] If the liquid inside the pipeline is in a flowing state, calculate the additional mass and inertial force generated by the liquid motion, and add the additional mass and inertial force of the liquid to the equivalent model; wherein, the inertial force of the fluid flowing inside the pipeline is expressed according to the following continuity equation and momentum equation:

[0027]

[0028] In the formula: ρ is the fluid density, t is the time, u is the fluid velocity, p is the pressure, and μ is the dynamic viscosity of the fluid;

[0029] Calculate the response of the pipeline under external impact or vibration, and add the additional mass of the liquid inside and outside the pipeline to the vibration model of the pipeline.

[0030] As a technical solution of the present application, in step S3, establish a fluid-structure interaction model between the pipeline structure and the liquid inside the pipeline, and determine the fluid boundary conditions and the boundary conditions of the pipeline structure; the boundary conditions of the pipeline structure include the initial state, flow velocity, pressure, temperature of the liquid inside and outside the pipeline, and the initial displacement, velocity, and boundary constraints of the pipeline structure;

[0031] According to the geometric shape, material properties, and boundary conditions of the pipeline structure and using the finite element method, calculate the vibration response of the pipeline under impact load; couple the fluid simulation and the structural analysis results to analyze the fluid-structure interaction effect; use the following basic equations of elasticity mechanics to describe the vibration response of the pipeline under impact load:

[0032]

[0033] In the formula: σ ij is the stress tensor, f i is the body force, u i is the displacement, ρ is the fluid density, and t is the time.

[0034] As a technical solution of the present application, in step S4, calculate the impact load received by each equivalent pipeline according to the actual working conditions and impact conditions of each equivalent pipeline; according to the impact load and characteristics of each equivalent pipeline, and calculate the reference acceleration A0 received by each equivalent pipeline according to the following formula:

[0035]

[0036] In the formula: A0 is; m ais the modal mass, and the modal mass of the ath mode is defined as:

[0037]

[0038] where: m i is the mass of the ith particle in the structure; x ia is the normalized modal displacement of the ith particle in the ath mode; P a is the modal participation factor.

[0039] As a technical solution of the present application, in step S5, analyze the response of the pipeline under impact load according to the following steps:

[0040] S51, Select representative pipelines: Select one or more representative pipelines from the equivalent pipelines for the application of the reference acceleration and the analysis of the pipeline response;

[0041] S52, Determine boundary conditions: Determine the boundary conditions of the selected pipeline, including the initial displacement, velocity, and boundary constraints of the pipeline;

[0042] S53, Apply reference acceleration: Apply the reference acceleration calculated in step S4 to the selected pipeline, and apply it to the pipeline structure step by step according to the time history characteristics of the reference acceleration and the time step to simulate the dynamic response of the pipeline under the impact load;

[0043] S54, Dynamic response analysis: Analyze the dynamic response of the pipeline under the action of the reference acceleration, and calculate the dynamic response parameters of the displacement, stress, and deformation of the pipeline according to the geometric shape, material properties, and boundary conditions of the pipeline;

[0044] S55, Evaluate the stability of the pipeline: Evaluate the stability and safety of the pipeline under the impact load according to the results of the dynamic response analysis;

[0045] S56, Optimize the design scheme: According to the evaluation results of the pipeline, propose an optimized pipeline design scheme, including adjusting the material, geometric shape, and support structure parameters of the pipeline.

[0046] As a technical solution of the present application, in step S6, evaluating the stability and safety of a single pipeline under impact load includes the following steps:

[0047] S61, Finite element analysis: Use the finite element method to analyze the structure of a single pipeline, and establish a finite element model of the pipeline according to the geometric shape, material properties, and boundary conditions of the pipeline;

[0048] S62, Apply load: Apply the impact load calculated in step S4 to the finite element model, and apply it to the pipeline structure step by step according to the time history characteristics of the reference acceleration and the time step;

[0049] S63, Solve the stress field: According to the finite element model and the applied loads, solve the stress distribution of each point in the pipeline structure; considering the mechanical properties of the pipeline material, calculate the stress field of the pipeline under impact loads.

[0050] S64, Stress evaluation: Evaluate the calculated stress distribution according to the following formula, compare the total stress in the pipeline structure with the allowable stress of the material, and evaluate the stability and safety of the pipeline under impact loads:

[0051]

[0052] In the formula: σ shock is the effective dynamic stress of the node; σ a(max) is the maximum value of the Von-Mises dynamic stress of all modes of the node; σ a is the Von-Mises dynamic stress at mode a of the node; assuming that σ work is the Von-Mises working stress of the node, then the total stress is:

[0053] σ total =|σ shock | + |σ work |;

[0054] Compare the total stress in the above formula with the allowable stress of the material to evaluate the impact resistance of the structure;

[0055] S65, Determine the key area: Determine the areas in the pipeline structure with greater stress or stress concentration as the key areas;

[0056] S66, Optimize the design scheme: According to the stress evaluation results, propose an optimized pipeline design scheme by adjusting the pipeline material, geometric shape, and support structure parameters.

[0057] As a technical solution of the present application, in step S7, compare the effective stress and modal stress of each order with the allowable stress according to the following steps:

[0058] S71, Determine the allowable stress of the pipeline material according to the mechanical property parameters of the pipeline material and the design specifications;

[0059] S72, Compare the pipeline stress distribution calculated in step S6 with the allowable stress, compare the stress values of each point in the pipeline structure with the allowable stress values to determine whether the pipeline structure meets the safety requirements;

[0060] S73. If the stress values in the pipeline structure are all lower than the allowable stress values, the pipeline is considered to be safe under impact loads; if the stress values in some key areas of the pipeline structure exceed the allowable stress values, they are dealt with by optimizing the design scheme, adding support structures, or adjusting materials.

[0061] S74. Record the safety check results in detail and generate corresponding documents or reports.

[0062] Advantages of the present application:

[0063] (1) High-precision model: The present invention uses more accurate mathematical models and physical models to describe the structure and stress conditions of the condenser; by considering more factors, such as the non-linear characteristics of materials and complex working environments, the accuracy of the calculation results can be effectively improved.

[0064] (2) Comprehensive consideration of factors: The present invention fully considers various factors affecting the impact resistance performance of the condenser, including material properties, structural design, environmental conditions, etc. By comprehensively considering these factors, the impact resistance performance of the condenser can be evaluated more comprehensively, providing a more powerful basis for design and improvement.

[0065] (3) Standardized method: The present invention proposes a unified standardized calculation method, which can promote cooperation and communication between different research institutions or enterprises, and improve the comparability and reliability of calculation results.

[0066] (4) Optimized calculation algorithm: The present invention uses an optimized calculation algorithm, which can effectively reduce the consumption of calculation time and calculation resources. By using efficient numerical calculation techniques or parallel calculation methods, the calculation time can be significantly shortened and the calculation efficiency can be improved. Description of the drawings

[0067] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0068] Figure 1 Schematic diagram of the arrangement of heat exchange tubes provided by the embodiment of the present application;

[0069] Figure 2 Schematic diagram of the flow chart of the method for calculating the impact resistance performance of the condenser provided by the embodiment of the present application;

[0070] Figure 3 Schematic diagram of the marine shell-and-tube condenser provided by the embodiment of the present application.

[0071] Accompanying drawings: 1 - tube sheet; 2 - heat exchange tube bundle. Detailed implementation manners

[0072] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. The components of the embodiments of the present application described and shown herein can be arranged and designed in various different configurations.

[0073] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application claimed, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0074] It should be noted that similar reference numerals and letters denote similar items in the following accompanying drawings. Therefore, once an item is defined in one accompanying drawing, it does not need to be further defined and explained in subsequent accompanying drawings.

[0075] Embodiment:

[0076] Please refer to Figure 1 , and in cooperation with reference to Figures 2 to 3 , a method for calculating the shock resistance performance of a condenser is provided in the embodiments of the present application, aiming to provide an accurate and efficient calculation method for evaluating the stability and safety of the condenser under external shock or vibration; it mainly includes the following steps:

[0077] S1. Establish an equivalent simplified system of the pipeline, simplify the complex pipeline system into fewer pipelines to facilitate modeling and calculation; the specific steps are as follows:

[0078] First, classify and segment the entire pipeline system, and divide it into different parts according to factors such as the function, position, and material of the pipeline:

[0079] For each pipeline part, determine its equivalent parameters according to its characteristics and the environment it is in, such as length, diameter, wall thickness, material elastic modulus, etc. When making the equivalence, first ensure that the mass of the tube sheet 1 and the heat exchange tube bundle 2 of the marine shell-and-tube condenser is the same, that is, ensure that the total cross-sectional area is the same under the same density; combine similar pipelines into an equivalent pipeline according to the actual situation, and the combination can be carried out according to factors such as the length, diameter, and material of the pipeline, ensuring that the simplified equivalent system can accurately reflect the characteristics of the original system;

[0080] For the connection part, its impact on the entire pipeline system needs to be specifically considered. It can be merged into one or more equivalent connecting pipes according to the quantity and position of the connection parts; verify the simplified equivalent system to ensure its characteristics match those of the original system. Numerical simulation or experimental verification can be carried out to verify the accuracy and reliability of the equivalent simplified system; finally, establish an equivalent model based on the simplified pipeline system. Mathematical models, physical models, or computer simulations in the existing technology can be used to model and calculate the system for further analysis and optimization;

[0081] S2. Calculate the added mass of the liquid inside and outside the pipeline, which involves the impact of the liquid inside and outside the pipeline on vibration and shock. It needs to be considered in the condenser model after equivalent treatment. The following are the specific methods for implementing this step:

[0082] For the liquid inside and outside the pipeline, its movement will affect the vibration characteristics of the pipeline. Therefore, first, calculate its mass according to parameters such as the density, volume, and flow velocity of the liquid inside and outside the pipeline; then, evenly distribute the liquid mass inside and outside the pipeline and consider it as added mass in the model. Specifically, in the entire condenser model, add its liquid added mass to the corresponding pipeline, and the pipeline can be thickened according to the size of the liquid added mass;

[0083] It should be noted that please refer to Figure 1 , the density of the heat exchange tubes of the condenser is equivalently obtained by dividing the sum of the attached water mass, the water mass inside the tube, and the mass of the tube by the volume of the tube. The calculation of the attached water mass is carried out using the attached water mass coefficient provided in the literature "Experimental Study on the Law of Attached Water Mass of Rod Bundles in Limited Water Areas". Among them, the attached water mass is generally estimated by an empirical formula. For a cylindrical pipeline m 附 = 2 / 3ρV, where ρ is the water density and V is the volume of water displaced by the pipeline. Since the test explosion shock is from bottom to top, it can be considered that the arrangement of the heat exchange tubes is in the y-direction arrangement;

[0084] If the liquid inside the pipeline is in a flowing state, the impact of liquid movement on the vibration characteristics of the pipeline needs to be considered. According to the theory of fluid mechanics, the added mass and inertial force generated by liquid movement can be calculated and considered in the model; the flow of fluid in the pipeline can be calculated by the following methods:

[0085]

[0086] In the formula: ρ is the fluid density, t is the time, u is the fluid velocity, p is the pressure, and μ is the dynamic viscosity of the fluid;

[0087] The added mass of the liquid inside and outside the pipeline is considered in the vibration model of the pipeline. Numerical simulation or analytical methods can be used to calculate the response of the pipeline under external impact or vibration, and the influence of the liquid added mass on the vibration characteristics is considered;

[0088] Through the above steps, the influence of the added mass of the liquid inside and outside the pipeline on the vibration characteristics of the pipeline can be comprehensively considered, providing accurate basic data for subsequent vibration and impact analysis;

[0089] S3. The simulation calculation method in the existing technology is used to calculate the fluid-structure interaction impact, that is, the interaction between the liquid inside the pipeline and the pipeline structure is considered, and the response of the pipeline under the impact load is further analyzed. The following is the specific method for implementing this step:

[0090] First, a fluid-structure interaction model between the pipeline structure and the liquid inside the pipeline is established; then, the fluid boundary conditions and the boundary conditions of the pipeline structure are determined, which include parameters such as the initial state, flow velocity, pressure, temperature, etc. of the liquid inside and outside the pipeline, and conditions such as the initial displacement, velocity, and boundary constraints of the pipeline structure;

[0091] The finite element method is used to analyze and calculate the vibration response of the pipeline structure; considering factors such as the geometric shape, material properties, and boundary conditions of the pipeline structure, the vibration response of the pipeline under the impact load is calculated; then, the fluid simulation and the structural analysis results are coupled and calculated, considering the fluid-structure interaction effect, and the response of the structure is described according to the following method:

[0092]

[0093] In the formula: σ ij is the stress tensor, f i is the body force, u i is the displacement, ρ is the fluid density, and t is the time;

[0094] Through the above steps, the fluid-structure interaction effect between the liquid inside and outside the pipeline and the pipeline structure can be comprehensively considered, and the response of the pipeline under the impact load can be further analyzed, including stress, displacement, acceleration, etc., providing an accurate reference basis for the design and improvement of the pipeline;

[0095] S4. Calculate the reference acceleration of the equivalent pipeline, that is, after simplifying the complex pipeline system into several or dozens of equivalent pipelines, calculate the reference acceleration received by each equivalent pipeline. The following is the specific method for implementing this step:

[0096] According to the division of equivalent pipelines, each equivalent pipeline is processed separately; according to factors such as the function, location, and material of the pipeline, it is divided into different parts or paragraphs; for each equivalent pipeline, the impact load it receives is calculated according to the actual working conditions and impact situation; according to the impact load and the characteristics of the equivalent pipeline, the reference acceleration received by each equivalent pipeline is calculated; the reference acceleration A0 is calculated according to the following method:

[0097]

[0098] In the formula: A0 is the reference acceleration; m a is the modal mass, and the modal mass of the a-th order mode is defined as:

[0099]

[0100] In the formula: m i is the mass of the i-th particle in the structure; x ia is the normalized modal displacement of the i-th particle in the a-th order mode; P a is the modal participation factor, which is a constant representing the contribution of each mode shape to the deformation in a specific direction;

[0101] Consider the dynamic response of the pipeline structure, including dynamic effects such as pipeline vibration and deformation; according to the principles of dynamics and structural characteristics, calculate the dynamic response of the pipeline under the action of impact load through existing numerical simulation techniques, and determine the time history characteristics of the reference acceleration;

[0102] Through the above steps, the reference acceleration received by each equivalent pipeline can be accurately calculated, providing an important reference for the design and improvement of the pipeline system, and ensuring the stability and safety of the pipeline system;

[0103] S5. Apply the calculated reference acceleration to a single pipeline to further analyze the response of the pipeline under impact load; the following is the specific implementation method:

[0104] S51. Select representative pipelines: Selecting pipelines with good representativeness can more accurately reflect the response of the entire pipeline system. Therefore, select one or more pipelines with better representativeness from the equivalent pipelines for the application of reference acceleration and the analysis of pipeline response. Specifically, select pipelines that are relatively weak in impact resistance and are more likely to be damaged under large impacts for analysis;

[0105] S52. Determine the boundary conditions: Determine the boundary conditions of the selected representative pipeline, including the initial displacement, velocity, boundary constraints, etc. of the pipeline. These boundary conditions will affect the vibration response of the pipeline under the action of impact load;

[0106] S53, Apply the reference acceleration: Apply the reference acceleration calculated in step S4 to the selected representative pipeline. According to the time - history characteristics of the reference acceleration, apply it to the pipeline structure step by step according to the time step to simulate the dynamic response of the pipeline under the impact load;

[0107] S54, Dynamic response analysis: Use existing finite - element analysis or other numerical simulation methods to analyze the dynamic response of the pipeline under the reference acceleration; Consider factors such as the geometric shape, material properties, and boundary conditions of the pipeline, and calculate dynamic response parameters such as the displacement, stress, and deformation of the pipeline through existing numerical simulation techniques;

[0108] S55, Evaluate the stability of the pipeline: According to the results of the dynamic response analysis, evaluate the stability and safety of the pipeline under the impact load; Check whether the stress condition of the pipeline exceeds the bearing capacity of the material, and determine whether further reinforcement or improvement measures are required;

[0109] S56, Optimize the design scheme: According to the evaluation results, propose an optimized pipeline design scheme; Parameters such as the material, geometric shape, and support structure of the pipeline can be adjusted to improve the stability and safety of the pipeline under the impact load;

[0110] S6, Obtain the stress distribution of a single pipeline to further evaluate the stability and safety of the pipeline under the impact load; The following is the specific method for implementing this step:

[0111] S61, Finite - element analysis: Use the finite - element method to analyze the structure of a single pipeline. According to the geometric shape, material properties, and boundary conditions of the pipeline, establish a finite - element model of the pipeline;

[0112] S62, Apply the load: Apply the impact load calculated in step S4 in the finite - element model; According to the time - history characteristics of the reference acceleration, apply it to the pipeline structure step by step according to the time step;

[0113] S63, Solve the stress field: According to the finite - element model and the applied load, use existing numerical simulation techniques to solve the stress distribution of each point in the pipeline structure; Consider the material mechanics properties of the pipeline and calculate the stress field of the pipeline under the impact load;

[0114] S64, Stress evaluation: Evaluate the calculated stress distribution; Compare the stress in the pipeline structure with the allowable stress of the material to evaluate the stability and safety of the pipeline under the impact load;

[0115] The dynamic stress assessment of the condenser equipment under impact environment is based on the von Mises failure criterion, that is, the effective stress of each order of mode and the modal stress after synthesis by the modal synthesis method are compared with the allowable stress; among them, the modal synthesis method adopted in the national military standard is the NRL (National Research Laboratory Modal Synthesis) method, as shown below:

[0116]

[0117] In the formula: σ shock is the effective dynamic stress of the node; σ a(max) is the maximum value of the dynamic stress of the von-Mises (referred to as the equivalent stress or yield stress) of all modes of the node; σ a is the dynamic stress of von-Mises at the modal a of the node; assuming that σ work is the von-Mises working stress of the node, then the total stress is:

[0118] σ total = |σ shock | + |σ work |;

[0119] Assuming that σ_work is the von-Mises working stress of the node, then the total stress is:

[0120] σ total = |σ shock | + |σ work |;

[0121] Compare the total stress in the above formula with the allowable stress of the material to evaluate the impact resistance of the structure;

[0122] S65, determine the key area: Determine the key areas in the pipeline structure, that is, the areas with greater force or stress concentration. These areas may be the weak links of the pipeline and need special attention;

[0123] S66, optimize the design scheme: According to the stress assessment results, propose an optimized pipeline design scheme, and the parameters such as the material, geometric shape, and support structure of the pipeline can be adjusted to improve the stability and safety of the pipeline under impact loads;

[0124] Through the above steps, the stress distribution of a single pipeline under impact loads can be comprehensively evaluated, providing an important reference for the design and improvement of the pipeline system, and ensuring the stability and safety of the pipeline system;

[0125] S7. Compare the effective stress of each order of mode and the modal stress synthesized by the modal synthesis method with the allowable stress to conduct a safety check. The following is the specific method for implementing this step:

[0126] S71. Determination of allowable stress: Determine the allowable stress of the pipeline material, which is usually determined based on the mechanical property parameters of the pipeline material and the design specifications. It should be noted that the allowable stress is the maximum stress value that the pipeline material can withstand, and exceeding this value will cause material failure or invalidation.

[0127] S72. Comparison between stress and allowable stress: Compare the pipeline stress distribution calculated in the sixth step with the allowable stress. Compare the stress values at each point in the pipeline structure with the allowable stress value to determine whether the safety requirements are met.

[0128] S73. Safety assessment: Conduct a safety assessment on the comparison results. If the stress values in the pipeline structure are all lower than the allowable stress value, it is considered that the pipeline has sufficient safety under impact loads. If there are stress values in some areas exceeding the allowable stress value, further analysis and treatment are required.

[0129] S74. Treatment of key areas: For the key areas with stress exceeding the limit, take corresponding treatment measures, such as optimizing the design scheme, adding support structures, adjusting materials, etc., to improve the bearing capacity of the key areas and ensure the stability and safety of the pipeline system.

[0130] S75. Result recording: Record the safety check results in detail and generate corresponding documents or reports, mainly including the pipeline stress distribution diagram, the comparison results with the allowable stress, the safety assessment conclusion, etc., for subsequent review and verification.

[0131] In summary, the present application provides a method for calculating the shock resistance performance of a condenser, and this method has the following advantages: (1) High-precision model: The present invention adopts more accurate mathematical models and physical models to describe the structure and force conditions of the condenser; by considering more factors, such as the non-linear characteristics of materials, complex working environments, etc., the accuracy of the calculation results can be effectively improved; (2) Comprehensive consideration of factors: The present invention fully considers various factors affecting the shock resistance performance of the condenser, including material properties, structural design, environmental conditions, etc. By comprehensively considering these factors, the shock resistance performance of the condenser can be evaluated more comprehensively, providing a more powerful basis for design and improvement; (3) Standardized method: The present invention proposes a unified standardized calculation method, which can promote cooperation and communication between different research institutions or enterprises, and improve the comparability and reliability of calculation results; (4) Optimized calculation algorithm: The present invention adopts numerical simulation algorithms and optimized calculation algorithms, which can effectively reduce the consumption of calculation time and calculation resources. By using efficient numerical calculation techniques or parallel calculation methods, the calculation time can be significantly shortened, the calculation efficiency can be improved, and the shock resistance performance of the condenser can be calculated and analyzed more quickly.

[0132] The foregoing is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A calculation method for the impact resistance performance of a condenser, characterized in that, It includes the following steps: S1. Establish an equivalent simplified system of the pipeline to obtain multiple equivalent pipes; S2. Calculate the additional mass of the liquid inside and outside each equivalent pipe; S3. Conduct fluid-structure interaction impact calculation; S4. Calculate the reference acceleration of each equivalent pipe; S5. Apply the calculated reference acceleration of each equivalent pipe to a single pipe to analyze the response of the single pipe under impact load; S6. Obtain the stress distribution of the single pipe to evaluate the stability and safety of the single pipe under impact load; S7. Compare the effective stress of each order of mode and the modal stress synthesized by the modal synthesis method with the allowable stress to conduct safety check.

2. The method for calculating the impact resistance performance of a condenser according to claim 1, wherein In step S1, classify and segment the entire pipeline system according to the function, location, and material of the pipeline: Determine the equivalent parameters of each pipe according to the characteristics and the environment where each pipe is located, and merge multiple similar pipes into an equivalent pipe according to the equivalent parameters of the pipe; Merge multiple similar connecting pipes into an equivalent connecting pipe according to the number and location of the connecting pipes; Verify the equivalent simplified system to make the characteristics of the equivalent simplified system match those of the original system; Establish an equivalent model according to the equivalent simplified system.

3. The method for calculating the impact resistance performance of a condenser according to claim 1, wherein In step S2, calculate the mass of the liquid inside and outside the pipe according to the density, volume, and flow velocity parameters of the liquid inside and outside the pipe; evenly distribute the liquid mass inside and outside the pipe, and add the liquid mass as additional mass to the equivalent model; If the liquid inside the pipe is in a flowing state, calculate the additional mass and inertial force generated by the liquid movement, and add the additional mass and inertial force of the liquid to the equivalent model; where, the inertial force of the fluid flowing in the pipe is expressed according to the following continuity equation and momentum equation: In the formula: ρ is the fluid density, t is the time, u is the fluid velocity, p is the pressure, and μ is the dynamic viscosity of the fluid; Calculate the response of the pipe under external impact or vibration, and add the additional mass of the liquid inside and outside the pipe to the vibration model of the pipe.

4. The method for calculating the impact resistance performance of a condenser according to claim 1, characterized in that, In step S3, establish a fluid-structure interaction model between the pipe structure and the liquid inside the pipe, and determine the fluid boundary conditions and the boundary conditions of the pipe structure; the boundary conditions of the pipe structure include the initial state, flow velocity, pressure, temperature of the liquid inside and outside the pipe, and the initial displacement, velocity, and boundary constraints of the pipe structure; Calculate the vibration response of the pipe under impact load according to the geometric shape, material properties, and boundary conditions of the pipe structure and using the finite element method; conduct coupled calculation on the fluid simulation and the structural analysis results to analyze the fluid-structure interaction effect; Describe the vibration response of the pipe under impact load using the following basic equations of elasticity mechanics: where: σ ij is the stress tensor, f i is the body force, u i is the displacement, ρ is the fluid density, and t is the time.

5. The method for calculating the impact resistance performance of the condenser according to claim 1, characterized in that In step S4, calculate the impact load received by each equivalent pipe according to the actual working conditions and impact conditions of each equivalent pipe; according to the impact load and characteristics of each equivalent pipe, and calculate the reference acceleration A0 received by each equivalent pipe according to the following formula: where: A0 is the reference acceleration; m a is the modal mass, and the modal mass of the ath mode is defined as: where: m i is the mass of the i-th particle in the structure; x ia is the normalized modal displacement of the i-th particle in the a-th mode; P a is the modal participation factor.

6. The method for calculating the impact resistance performance of a condenser according to claim 1, characterized in that In step S5, analyze the response of the pipe under impact load according to the following steps: S51. Select representative pipes: Select one or more representative pipes from the equivalent pipes to apply the reference acceleration and analyze the pipe response; S52. Determine boundary conditions: Determine the boundary conditions of the selected pipeline, including the initial displacement, velocity, and boundary constraints of the pipeline; S53. Apply the reference acceleration: Apply the reference acceleration calculated in step S4 to the selected pipeline. According to the time history characteristics of the reference acceleration and in accordance with the time step, gradually apply it to the pipeline structure to simulate the dynamic response of the pipeline under the impact load; S54. Dynamic response analysis: Analyze the dynamic response of the pipeline under the action of the reference acceleration. Calculate the dynamic response parameters of the displacement, stress, and deformation of the pipeline according to the geometric shape, material properties, and boundary conditions of the pipeline; S55. Evaluate the stability of the pipeline: Evaluate the stability and safety of the pipeline under the impact load according to the results of the dynamic response analysis; S56. Optimize the design scheme: According to the evaluation results of the pipeline, propose an optimized pipeline design scheme, including adjusting the material, geometric shape, and support structure parameters of the pipeline.

7. The method for calculating the impact resistance performance of a condenser according to claim 1, wherein In step S6, evaluating the stability and safety of a single pipeline under impact load includes the following steps: S61. Finite element analysis: Use the finite element method to analyze the structure of a single pipeline. According to the geometric shape, material properties, and boundary conditions of the pipeline, establish a finite element model of the pipeline; S62. Apply the load: Apply the impact load calculated in step S4 to the finite element model. According to the time history characteristics of the reference acceleration, gradually apply it to the pipeline structure in accordance with the time step; S63. Solve the stress field: According to the finite element model and the applied load, solve the stress distribution of each point in the pipeline structure; Considering the mechanical properties of the pipeline material, calculate the stress field of the pipeline under the impact load; S64. Stress evaluation: Evaluate the calculated stress distribution according to the following formula, compare the total stress in the pipeline structure with the allowable stress of the material, and evaluate the stability and safety of the pipeline under the impact load: Where: σ shock is the effective dynamic stress of the node; σ a(max) is the maximum value of the Von-Mises dynamic stress of all modes of the node; σ a is the Von-Mises dynamic stress at mode a of the node; Assume σ work is the Von-Mises working stress of the node, then the total stress is: σ total = |σ shock | + |σ work |; Compare the total stress in the above formula with the allowable stress of the material to evaluate the impact resistance of the structure; S65. Determine the key area: Determine the areas in the pipeline structure with larger forces or stress concentrations as key areas; S66. Optimize the design scheme: According to the stress evaluation results, propose an optimized pipeline design scheme by adjusting the material, geometric shape, and support structure parameters of the pipeline.

8. The method for calculating the impact resistance performance of a condenser according to claim 1, wherein, In step S7, compare the effective stress and modal stress of each order with the allowable stress according to the following steps: S71. Determine the allowable stress of the pipeline material according to the mechanical property parameters of the pipeline material and the design code; S72. Compare the stress distribution of the pipeline calculated in step S6 with the allowable stress, and compare the stress values of each point in the pipeline structure with the allowable stress values to determine whether the pipeline structure meets the safety requirements; S73. If the stress values in the pipeline structure are all lower than the allowable stress values, it is considered that the pipeline is safe under the impact load; If the stress values in some key areas of the pipeline structure exceed the allowable stress values, deal with them by optimizing the design scheme, adding support structures, and adjusting materials; S74. Record the safety check results in detail and generate corresponding documents or reports.

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