Simulation analysis system and method for system-level pipe network in nuclear power plants

Abstract

The present invention provides a simulation and analysis system and method for a system-level pipeline network of a nuclear power plant, comprising: constructing a nuclear power pipeline network system simulation model based on the connection relationship of components in the nuclear power pipeline network system and a pre-constructed component model; and receiving external parameter input to perform parameter settings on the nuclear power pipeline network system; based on the parameter settings of the nuclear power pipeline network system and preset conservation equations, simulating and solving the nuclear power pipeline network system in a modular solution manner to obtain the pressure, flow and temperature distribution in the nuclear power pipeline network system; integrating professional standard component models including fire protection systems, HVAC systems, traditional piping systems, circulation systems and control systems; and constructing a working fluid physical property parameter library for the nuclear power pipeline network system including general working fluid characteristics, special working fluid physical properties and solid material properties; and providing a model exchange interface that supports third-party three-dimensional pipeline layout software.

Description

Technical Field

[0001] The present invention belongs to the technical field of pipe network thermal fluid simulation in the nuclear power field, and in particular relates to a simulation analysis system and method for a system-level pipe network in a nuclear power plant. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Nuclear power projects are large, complex systems involving over one hundred process systems performing diverse functions. These systems are interconnected by pipes, tees, reducers, pumps, valves, orifice plates, vessels, heat exchangers, and various measurement and control instruments, forming a vast fluid piping network. Nuclear power process systems require extensive simulation and verification at every stage, from requirements definition and function allocation to logical design and physical implementation. System-level piping network simulation analysis is a crucial task during the construction and design phase of nuclear power process systems. The analysis results, including flow rate, flow velocity, pressure, temperature, and flow resistance, are crucial for ensuring design rationality.

[0004] Existing technical solutions typically use Excel or foreign simulation software. Using Excel for simulation presents significant manual input workload and difficulty in iterative solution generation. Using foreign simulation software presents challenges such as model conversion difficulties and a lack of specialized nuclear power component and working fluid libraries. As fluid system design data continues to accumulate, design experience data is managed and manipulated solely by humans. This management approach has numerous drawbacks, including low efficiency, poor confidentiality, and the generation of large volumes of files and data over extended periods of time (often with significant redundancy or inconsistencies in data intended for the same purpose). This creates significant challenges in finding, updating, and maintaining these files. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a simulation and analysis system and method for the system-level pipeline network of a nuclear power plant. The scheme uses a parameterized method to quickly establish a nuclear power pipeline network system simulation model. By pre-establishing a component library and a working fluid library, appropriate components can be selected according to the actual nuclear power pipeline network system to form a connection logic diagram. Then, the parameters of the nuclear power pipeline network system are set, and the corresponding conservation equations are constructed through a solver for simulation calculation, thereby realizing rapid simulation of a specific object complex nuclear power pipeline network system; at the same time, the scheme is aimed at complex nuclear power pipeline network systems of different professions, and can select components corresponding to each profession in the component library and working fluid parameters corresponding to the working fluid physical parameter library, thereby enhancing the versatility of the nuclear power pipeline network system modeling and simulation method, and has good and wide applicability.

[0006] According to a first aspect of an embodiment of the present invention, a simulation and analysis system for a system-level pipe network of a nuclear power plant is provided, comprising:

[0007] The visual modeling module is used to build a simulation model of the nuclear power pipe network system based on the connection relationship of the components in the nuclear power pipe network system and the pre-built component models; and receive external parameter input to perform parameter settings on the nuclear power pipe network system;

[0008] A solver module is used to simulate and solve the nuclear power pipe network system using a modular solution method based on the parameter settings of the nuclear power pipe network system and preset conservation equations, thereby obtaining the pressure, flow, and temperature distribution in the nuclear power pipe network system. The modular solution method specifically includes a main process using the Newton-Raphson iterative method and a branch process based on the results of each iteration of the main process.

[0009] Component library and working fluid library modules are used to integrate professional standard component models including fire protection systems, HVAC systems, traditional piping systems, circulation systems, and control systems; and to build a working fluid physical property parameter library for nuclear power pipeline systems, including general working fluid characteristics, special working fluid physical properties, and solid material properties;

[0010] The interface module is used to provide a model exchange interface that supports third-party 3D piping layout software.

[0011] In a specific implementation, the main process of the Newton-Raphson iteration method is as follows: the Newton-Raphson iteration method is adopted, and its iteration variables include the state quantity on each node of the nuclear power pipe network system and the process quantity on each branch;

[0012] Or, a branch process based on the result of each iteration of the main process, specifically: according to the state quantity and process quantity of each iteration of the main process, the fluid equations including the energy equation, component equation and fluid-solid coupling equation are solved through the branch process.

[0013] In the specific implementation, in the component library and working fluid library modules, the component library includes component models of pipes, elbows, orifice plates, valves, pumps and containers, and the working fluid library includes lubricating oil, boric acid aqueous solution, heavy water, seawater, ethylene glycol aqueous solution, etc., which meet the working fluid physical properties parameters in various application scenarios such as process, diesel engine, water supply and drainage, fire protection and circulation.

[0014] In a specific implementation, the system also includes a pre-processing module, which is used to perform mathematical parameterized modeling on each type of pipeline network element according to its one-dimensional flow characteristics and actual one-dimensional flow physical process; and to digitally abstract the physical processes and parameterized characteristics of different elements and classify them into different types of elements.

[0015] In a specific implementation, the system further includes a post-processing module, which is used to perform visualization processing and display of the solution results based on the simulation solution results.

[0016] In a specific implementation, the system also includes a database module, which is used to process data from four levels: the nuclear power pipe network system, subsystems, complex component models and specific attribute parameters, so as to create a clear hierarchical structure in the database.

[0017] In a specific implementation, the interface module includes a three-dimensional pipeline model conversion interface, an FMU model interface, and a command line calling interface.

[0018] According to a second aspect of an embodiment of the present invention, a simulation analysis method for a system-level pipe network of a nuclear power plant is provided. The simulation analysis method is based on the above-mentioned simulation analysis method for a system-level pipe network of a nuclear power plant, and includes:

[0019] Based on the connection relationship of the components in the nuclear power pipe network system to be simulated and the pre-built component models in the component library and working fluid library modules, the nuclear power pipe network system simulation model is constructed; or the pre-built model of the third-party 3D piping layout software is imported through the interface of the interface module; and the external parameter input is received to perform parameter setting of the nuclear power pipe network system;

[0020] Based on the parameterized settings of the nuclear power pipe network system and the preset conservation equations, a modular solution method is used to simulate and solve the nuclear power pipe network system to obtain the pressure, flow and temperature distribution in the nuclear power pipe network system; wherein, the modular solution method specifically includes a main process using the Newton-Raphson iterative method and a branch process based on the results of each iteration of the main process.

[0021] According to a third aspect of an embodiment of the present invention, an electronic device is provided, comprising a memory, a processor, and a computer program stored and running on the memory, wherein when the processor executes the program, the simulation and analysis method for the system-level pipeline network of a nuclear power plant is implemented.

[0022] According to a fourth aspect of an embodiment of the present invention, a non-transitory computer-readable storage medium is provided, on which a computer program is stored. When the program is executed by a processor, the simulation and analysis method for the system-level pipeline network of a nuclear power plant is implemented.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention provides a simulation analysis system and method for a system-level pipeline network of a nuclear power plant. The scheme uses a parameterized method to quickly establish a nuclear power pipeline network system simulation model. By pre-establishing a component library and a working fluid library, appropriate components can be selected according to the actual nuclear power pipeline network system to form a connection logic diagram. Then, the parameters of the nuclear power pipeline network system are set, and the corresponding conservation equations are constructed through a solver for simulation calculation, thereby realizing rapid simulation of a specific object complex nuclear power pipeline network system. At the same time, the scheme can select components corresponding to each profession in the component library and working fluid parameters corresponding to the working fluid physical parameter library for complex nuclear power pipeline network systems of different professions, thereby enhancing the versatility of the nuclear power pipeline network system modeling and simulation method, and has good and wide applicability.

[0025] (2) The solver of the solution described in the present invention is based on the core solver and its general underlying computing logic. It solves all control equations through the outer Newton-Raphson method and the step-by-step iteration method, and integrates synchronous solution and asynchronous solution schemes to solve the fluid network equations that describe flow heat transfer, phase change, mixing, fluid-solid coupling and multiple source terms, and obtains the distribution of pressure, flow, temperature, etc. in the pipe network system; the solver makes the entire solution process more stable by decoupling. The main state quantities and process quantities of the fluid network are involved in the solution of other parameters only after iteration, which can reduce the solution time while ensuring accuracy.

[0026] (3) The solver is designed to solve a set of fluid network equations that describe flow, heat transfer, phase change, mixing, and multiple source terms, and obtain the distribution of pressure, flow, temperature, etc. in the pipe network system. A robust and efficient numerical algorithm is established to quickly solve a large set of nonlinear equations, saving the large amount of memory and time consumed in constructing large Jacobi matrices and solving large linear equations.

[0027] (4) The component library and working fluid library described in the present invention integrate a nuclear power-specific component library and a working fluid library. The component library includes pipes, elbows, orifice plates, valves, pumps, containers, etc., and the working fluid library includes lubricating oil, boric acid aqueous solution, heavy water, seawater, ethylene glycol aqueous solution, etc., meeting various application scenarios in processes, diesel engines, water supply and drainage, fire protection, circulation, etc. This avoids the use of multiple different simulation software for multiple disciplines and also avoids errors caused by manually searching manuals.

[0028] (5) The database described in the present invention adopts a flexible data storage, call and management method. It includes a layer-by-layer structure, multiple storage methods, and multiple data processing methods. The database adopts a multi-level processing method to process data from four levels: the overall system, subsystem, complex component model and specific attribute parameters. A clear hierarchical structure can be created in the database to make the relationship between data clearer. The most suitable method for storage and processing can be selected according to the characteristics of the data (relational, graphic, document). The different fitting, interpolation and expansion methods adopted facilitate data modification, error checking, call and transplantation.

[0029] (6) The solution described in the present invention supports model exchange with three-dimensional pipeline layout software through JavaScript scripts, significantly improving the efficiency of pipeline network simulation model building, saving more than 90% of modeling time, and reducing human error. The present invention can implement the import and export functions of the FMI interface, can interact with external simulation software models, and can call special model components of external simulation software to improve the accuracy of system pipeline network simulation. The present invention can use Python language for calling and supports JavaScript language for scripting, which can realize batch simulation and significantly improve simulation speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0031] Figure 1 This is a software overall architecture diagram of a simulation and analysis system for a system-level pipe network in a nuclear power plant according to an embodiment of the present invention;

[0032] Figure 2 A diagram showing the relationship between software modules of a simulation and analysis system for a system-level pipe network in a nuclear power plant according to an embodiment of the present invention;

[0033] Figure 3 This is a connection logic diagram of a simulation analysis system for a system-level pipe network in a nuclear power plant according to an embodiment of the present invention;

[0034] Figure 4 This is a flow chart for solving control equations of a simulation analysis system for a system-level pipe network in a nuclear power plant according to an embodiment of the present invention;

[0035] Figure 5 This is a flowchart of a discrete algorithm solution for a simulation analysis system for a system-level pipe network of a nuclear power plant according to an embodiment of the present invention;

[0036] Figure 6This is a component library architecture diagram of a simulation and analysis system for a system-level pipe network in a nuclear power plant according to an embodiment of the present invention;

[0037] Figure 7 This is a diagram of the working fluid library architecture of a simulation and analysis system for a system-level pipe network in a nuclear power plant according to an embodiment of the present invention;

[0038] Figure 8 This is a database architecture diagram of a simulation and analysis system for a system-level pipe network in a nuclear power plant according to an embodiment of the present invention;

[0039] Figure 9 This is a pump data structure diagram of a simulation analysis system for a system-level pipe network in a nuclear power plant according to an embodiment of the present invention;

[0040] Figure 10 This is a performance diagram page architecture diagram of a simulation analysis system for a system-level pipeline network in a nuclear power plant described in an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0042] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0043] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0044] In the absence of conflict, the embodiments of the present invention and the features thereof may be combined with each other.

[0045] Example 1:

[0046] The purpose of this embodiment is to provide a simulation analysis system for a system-level pipe network of a nuclear power plant.

[0047] A simulation and analysis system for a system-level pipe network in a nuclear power plant, comprising:

[0048] The visual modeling module is used to build a simulation model of the nuclear power pipe network system based on the connection relationship of the components in the nuclear power pipe network system and the pre-built component models; and receive external parameter input to perform parameter settings on the nuclear power pipe network system;

[0049] A solver module is used to simulate and solve the nuclear power pipe network system using a modular solution method based on the parameter settings of the nuclear power pipe network system and preset conservation equations, thereby obtaining the pressure, flow, and temperature distribution in the nuclear power pipe network system. The modular solution method specifically includes a main process using the Newton-Raphson iterative method and a branch process based on the results of each iteration of the main process.

[0050] Component library and working fluid library modules are used to integrate professional standard component models including fire protection systems, HVAC systems, traditional piping systems, circulation systems, and control systems; and to build a working fluid physical property parameter library for nuclear power pipeline systems, including general working fluid characteristics, special working fluid physical properties, and solid material properties;

[0051] The interface module is used to provide a model exchange interface that supports third-party 3D piping layout software.

[0052] In a specific implementation, the main process of the Newton-Raphson iteration method is as follows: the Newton-Raphson iteration method is adopted, and its iteration variables include the state quantity on each node of the nuclear power pipe network system and the process quantity on each branch;

[0053] Or, a branch process based on the result of each iteration of the main process, specifically: according to the state quantity and process quantity of each iteration of the main process, the fluid equations including the energy equation, component equation and fluid-solid coupling equation are solved through the branch process.

[0054] In the specific implementation, in the component library and working fluid library modules, the component library includes component models of pipes, elbows, orifice plates, valves, pumps and containers, and the working fluid library includes lubricating oil, boric acid aqueous solution, heavy water, seawater, ethylene glycol aqueous solution, etc., which meet the working fluid physical properties parameters in various application scenarios such as process, diesel engine, water supply and drainage, fire protection and circulation.

[0055] In a specific implementation, the system also includes a pre-processing module, which is used to perform mathematical parameterized modeling on each type of pipeline network element according to its one-dimensional flow characteristics and actual one-dimensional flow physical process; and to digitally abstract the physical processes and parameterized characteristics of different elements and classify them into different types of elements.

[0056] In a specific implementation, the system further includes a post-processing module, which is used to perform visualization processing and display of the solution results based on the simulation solution results.

[0057] In a specific implementation, the system also includes a database module, which is used to process data from four levels: the nuclear power pipe network system, subsystems, complex component models and specific attribute parameters, so as to create a clear hierarchical structure in the database.

[0058] In a specific implementation, the interface module includes a three-dimensional pipeline model conversion interface, an FMU model interface, and a command line calling interface.

[0059] For ease of understanding, the solution described in this embodiment is described in detail below with reference to the accompanying drawings:

[0060] In order to solve the problems existing in the existing technology, this embodiment provides a simulation and analysis system for the system-level pipeline network of a nuclear power plant, which is used to realize the simulation conditions of compressibility, incompressibility, flow, heat transfer, transient, steady state, etc. of the fluid in the nuclear power process system. The simulation results can quantitatively analyze the physical quantities such as pressure, flow, temperature, etc. of the fluid pipeline system.

[0061] like Figure 1 As shown in the figure, the system described in this embodiment consists of modules such as general components, fluid base classes, modeling functions, core algorithms, and a database. General components contain geometry and attribute information for various component libraries, fluid base classes contain information about various fluid media, modeling functions include drag-and-drop additions and deletions, model settings, and converting pipe network diagrams to vector data. Core algorithms include governing equations and discrete algorithms, and the database includes functions for adding, deleting, storing, saving, and retrieving data.

[0062] like Figure 2 As shown, the system specifically includes the following modules:

[0063] (1) Pre-processing module: The data structure in the nuclear power pipe network system is based on the components in the real physical scene. For each type of pipe network component, according to its one-dimensional flow characteristics and the actual one-dimensional flow physical process, each characteristic and physical process is mathematically parameterized and modeled, including its pressure loss model, heat transfer model, etc.

[0064] Specifically, the pre-processing module implements the following process:

[0065] For each type of pipe network component, mathematical parameterized modeling is performed based on its one-dimensional flow characteristics and the actual one-dimensional flow physical processes. This includes pressure drop models, heat transfer models, and fluid-structure interaction models. Based on the physical processes and parameterized characteristics of each component, such as its property parameters, pressure drop models, heat transfer models, and other related parameters, these components are digitally abstracted and classified into different component types. In this step, different types of pipes and connectors with common features within the complex nuclear power pipe network system are sorted separately, and relevant parameters are abstracted based on their structure and actual physical processes.

[0066] (2) Visual modeling module: Based on the connection relationship of the pipeline network components in the actual nuclear power pipeline network system, the parameterized model formed in the previous processing module is used as the basis for connection, and a connection logic diagram is constructed to form a system simulation model of the nuclear power pipeline network system. The parameter form of the connection relationship between the components is established, and the input parameter form of the system simulation model is established. The input parameter form includes structural parameters and initial parameters, so that the nuclear power pipeline network system can be parameterized. The boundary parameters include flow boundary and pressure boundary. The pressure boundary is used to transmit pressure parameters, and the flow boundary is used to transmit flow parameters.

[0067] Specifically, the visual modeling module implements the following process:

[0068] Based on the resulting nuclear power piping system connection logic diagram, parameters are set for each piping network and connector component. Common attribute parameters for a typical nuclear power piping network system include dimensional and structural parameters, pressure loss coefficient, flow area, heat transfer calculation coefficient, and physical quantities. Initial parameters for a nuclear power piping network system include the required inputs of initial flow, initial pressure, and initial temperature. Boundary parameters and internal parameters for the piping network system calculations are constructed. Boundary parameters include flow and pressure boundaries. Pressure boundaries transmit pressure parameters within the piping network, while flow boundaries transmit flow parameters within the piping network. Internal parameters, or connection nodes, are used to transmit parameters required for internal calculations within the complex nuclear power piping network system. These primarily include pressure, flow, temperature, and other source parameters at the connection points.

[0069] (3) Solver Module: Based on the core solver and its general underlying computational logic, the module solves all governing equations using the outer Newton-Raphson method and a step-by-step iterative approach. It also integrates synchronous and asynchronous solution schemes to solve the fluid network equations that describe flow, heat transfer, phase change, mixing, fluid-structure interaction, and various source terms, and obtains the distribution of pressure, flow, temperature, and other parameters within the pipe network. The Newton-Raphson method is primarily used to solve nonlinear equations consisting of highly coupled mass conservation, momentum conservation, and state equations.

[0070] Conservation of mass:

[0071]

[0072] Conservation of momentum:

[0073]

[0074]

[0075] Conservation of Energy:

[0076]

[0077] Where, ρ is the fluid density; u is the axial fluid velocity; τ is the time step; Δx is the space step; u is the time step r - radial fluid velocity; K f - flow resistance coefficient; g-gravitational acceleration; θ-angle between the direction of gravity and the pipe axis; R-inner diameter of the pipe; μ-viscosity; e-total energy per unit mass of fluid; q-heat; h-enthalpy; Q-external energy source.

[0078] As an effective method for solving nonlinear equations, the Newton-Raphson method involves two key steps: constructing the Jacobi coefficient matrix and solving the linear system to determine the correction factor. For large-scale fluid pipe networks, the Newton-Raphson method requires solving a large nonlinear system of equations. Constructing the Jacobi matrix and solving the large linear system consumes a significant amount of memory and time, placing higher demands on the algorithm's timeliness.

[0079] Specifically, in the solver module, the setting parameters of the above steps are passed to the solver, and the solver processes different physical quantities into corresponding conservation equations, including conservation of mass, conservation of energy, conservation of momentum, etc. For fluid-solid coupling calculations, hybrid calculations, phase change calculations, etc., it also includes component conservation equations, solid energy conservation equations, heat transfer source term equations, two-phase flow equations, etc.

[0080] The solver provides a decoupled solution, using a modular solution process with different parameters and equations (see Figure 4 The main module solution process uses the Newton-Raphson iteration method, whose iterative variables include the state quantities on each node, such as pressure and resident mass, and the process quantities on each branch, such as flow parameters such as flow rate and velocity. Outside the main module process, other fluid equations, such as the energy equation, component equation, and fluid-solid coupling equation, are solved based on the basic state quantities and process quantities of each main iteration. Such a decoupling process makes the entire solution process more stable. The main state quantities and process quantities of the fluid network are only involved in the solution of other parameters after iteration, which can reduce the solution time while ensuring accuracy.

[0081] The iteration of other equations outside the main process is also embedded in the entire process in a modular manner. The energy equation, component equation, multiphase flow equation, and fluid-solid coupling equation are all solved in a sub-module manner. After obtaining the input data from the main solution module, other quantities such as enthalpy, entropy, temperature, component concentration, etc. are obtained according to the characteristics of the equation itself. Then, they participate in the main iteration in the form of known parameters, and the state quantity and process quantity of the next main iteration are obtained in a cycle until the calculation of the entire fluid network is completed. This method refers to the calculation scheme of mainstream CFD, reducing the complexity of the solution and the number of numerical iterations. In addition, due to the modular solution, there are specific relaxation parameters and convergence criteria for each type of equation. If you want to speed up the solution of the energy equation, you only need to adjust the energy solution relaxation parameters in the interactive scheme to achieve accelerated calculation of enthalpy, entropy and temperature without affecting the solution process of other variables.

[0082] The pipe network control equations solved by the Newton-Raphson method are as follows:

[0083]

[0084]

[0085] H(p,m)=0

[0086] in, The mass equations constructed for the nodes; is the momentum equations for the branches; the variable H(p,m) = 0 is the state equations for the nodes. The total number of equations and variables to be solved is the sum of the number of nodes * 2 and the number of branches.

[0087] Based on the structural characteristics of the above equations, in order to realize the above design, the present invention adopts the following technical solutions:

[0088] (a) Calculate the Jacobi coefficient matrix in blocks

[0089] As one of the key steps in Newton-Raphson, it is necessary to construct the Jacobi coefficient matrix during each iterative calculation process. According to the definition of the Jacobi matrix, the above nonlinear control equations have the following Jacobi matrix A:

[0090]

[0091] According to the definition of the pipe network system control equations, it can be seen that Therefore, a block-by-block approach can be used to calculate the coefficient matrix elements, reducing the calculation of some unnecessary elements. This can significantly reduce the time required to construct the coefficient matrix, especially for solving large-scale pipe network systems.

[0092] (b) Solving large sparse linear systems

[0093] After constructing the Jacobi coefficient matrix, a system of linear equations must be solved to determine the current iterative corrections to the variables. Based on the node and branch definition of the pipe network system and the aforementioned governing equations, the Jacobi coefficient matrix A is sparse, meaning that the nonzero subblock matrices are sparse. Traditional direct solutions to linear systems are no longer suitable, necessitating the development of efficient algorithms for solving large sparse linear systems. The Pardiso solver, a sparse matrix solver within the core math functions, is a high-performance, thread-safe, parallel algorithm for solving large sparse symmetric and asymmetric linear systems. Taking advantage of the sparse nature of the Jacobi coefficient matrix A, the Pardiso function is used to solve large sparse linear systems to determine the current iterative corrections to the variables. Before calling the Pardiso function, A is stored in the Compressed Sparse Row (CSR) format to meet the input parameter settings of the Pardiso function. Additionally, the user interface has added options for solving linear systems: the Gaussian method and the Pardiso method.

[0094] (c) Specific solution process

[0095] According to the definition of the Jacobi coefficient matrix and the structural characteristics of the pipe network system, the coefficient matrix elements are calculated in blocks; the function CSRFormat() is added to store the Jacobi coefficient matrix in CSR format; the function pardiso_unsys() is added to call the pardiso interface to solve the linear equation system; the call of the pardiso function is embedded in the Newton-Raphson method iterative calculation process to complete the solution of the entire model; a large-scale nuclear power pipe network system is established, and the working fluid and related parameter settings are completed. The user selects the pardiso solver in the interface to quickly solve the entire system. The discrete algorithm solution process is shown in Figure 5 .

[0096] (4) Post-processing module: After the fluid pipe network system is successfully calculated, the simulation results can be post-processed and displayed graphically, including pressure or temperature cloud maps and two-dimensional curve charts. At the same time, a convenient and professional post-processing interface is provided, which can realize parameter selection, table and curve output functions. After the system simulation model is completed and the dynamic characteristics simulation calculation of the nuclear power pipe network system is carried out, the simulation output parameter form is established, and the simulation output parameter form includes output parameters that change over time.

[0097] Specifically, the post-processing module specifically performs the following processing:

[0098] Construct a post-processing parameter form for simulation calculation results. The post-processing parameter form supports qualitative display of chromatography and quantitative expression of tables. Graphs can be drawn simultaneously with multiple windows, multiple curves, and multiple axes, or displayed as pointer instruments or directly displayed digitally in the pipe network. Display is supported as pointer instruments, and the range of the instrument panel is input by the user, including pressure, temperature, flow rate, and flow velocity. The instrument panel can be displayed or closed. At the same time, the parameter list can be displayed according to the user-configured parameters and form a fixed template. The interface conforms to professional logic and can realize parameter selection, table, and curve output functions. It supports the generation of text reports, which include important information such as operation time, algorithm settings, layout settings, fluid information, system performance parameters, component performance parameters, fluid precipitation, etc., and supports the output of text reports in PDF format.

[0099] (5) Component library module: System-level pipe network simulation of nuclear power plants involves multiple application scenarios such as process, diesel engine, water supply and drainage, fire protection, circulation, etc. Existing commercial software only includes ordinary conventional component libraries and cannot meet the needs of these professional applications. The present invention integrates the component types and calculation standards of various professional manuals such as "Internal flow system", GB 50974 "Technical Specification for Fire Water Supply and Fire Hydrant System", GB50084 "Design Specification for Automatic Sprinkler Fire Extinguishing System", NFPA 13 "Standard for the Installation of Sprinkler Systems", Practical Heating and Air Conditioning Design Manual, Crane TP410, "FLOW OF FLUIDS Through Valves, Fittings and Pipe." The components include pipes, elbows, orifice plates, valves, pumps, containers, etc., covering multiple application scenarios such as nuclear power process, diesel engine, water supply and drainage, fire protection, circulation, etc.

[0100] Specifically, such as Figure 6 As shown, the component library module includes general component geometry, parameter descriptions, and calculation coefficient definition, import, and expansion. The component library includes pipes (circular, rectangular, elliptical, and concentric pipes), fittings (tees, crosses, elbows, sudden expansions, sudden contractions), orifice plates (single-stage and multi-stage), valves (butterfly, angle, ball, gate, and check valves), pumps (centrifugal and fans), and containers (water tanks and compressed gas cylinders). It covers flow and heat transfer calculations, encompassing a variety of application scenarios in water supply and drainage, fire protection, and circulation systems.

[0101] The above components are based on integrated nuclear power-specific components and are expanded to other complex model components, such as dehumidifiers, steam generators, and other power components. The component library in this application integrates components that meet professional manual standards for fire protection systems, HVAC systems, traditional piping systems, circulation systems, control systems, and other professional manuals. Its construction method has the following characteristics:

[0102] a) Basic Model Development: Develop a basic parameter model for a specific component type, such as a circular cross-section pipe, where the basic parameters are length, diameter, and roughness. The most important calculation model for pipes in fluid networks is the pressure loss model. Different professional manuals and specifications have different parameters and calculation methods for pressure loss. This application provides a mapping method for these different parameters and models.

[0103] b) Parameter and model mapping method: Taking circular cross-section pipes as an example, combined with graphical interface modeling, components connect modeling graphics with internal calculation logic in a "one-to-many" mapping and expansion manner. The parameter options of the component include a variety of standard options. Through the interface interaction, the calculation parameters corresponding to the calculation scenario are selected manually or automatically. For example, for the fire protection system, the pipeline graphic interface will display the parameters for fire protection scenario calculation: national standard selection and external standard options. For different selection options, the corresponding attribute parameter options will be given to the interactive interface in the form of an interface or pop-up window. Selecting these attribute parameter options automatically determines the calculation logic, and these operations and selections are completed in the graphical interface of the same component, avoiding the use of multiple different component graphics and models to distinguish the corresponding calculation scenarios.

[0104] c) Targeted component classification: In combination with the component scenario requirements and calculation logic described above, this method makes a more targeted classification of various types of components. Unlike the classification in other similar applications, this method does not simply classify components according to the major categories they belong to. For example, pumps and fans are power components. However, in this method, in addition to the power type, pumps and fans are also classified according to their working media and the type of data they use.

[0105] (6) Working fluid library module: Establish the physical parameter form of the working fluid of the nuclear power pipeline network system and form the working fluid physical parameter library of the nuclear power pipeline network system, so as to select the required working fluid and physical properties for the nuclear power pipeline network system that needs to be modeled and simulated, including lubricating oil, boric acid aqueous solution, heavy water, seawater, ethylene glycol aqueous solution and other nuclear power system-specific working fluids.

[0106] Specifically, such as Figure 7As shown, the working fluid library module includes general working fluid characteristics, special working fluid physical properties, and solid material properties. Physical property parameter forms for working fluids in nuclear power pipeline networks are established, forming a working fluid physical property parameter library for nuclear power pipeline networks. This allows selection of required working fluids and physical properties for the nuclear power pipeline network systems to be modeled and simulated. These include lubricating oil, aqueous boric acid solution, heavy water, seawater, ethylene glycol solution, and other nuclear power system-specific working fluids. Among the working fluid physical property parameters, water has two phases: vapor and liquid, and oil includes fuel oil and lubricating oil. Based on actual needs and different working fluid ratios and physical property structures, mixed working fluids are constructed to enable mixed configuration and calculation of multiple components.

[0107] (7) Database module: A system that stores and manages fluid network data according to data structures. It contains historical simulation data, experimental data, and theoretical models for each component. It binds components to their corresponding data and rationally organizes all data required by the network system. It supports data processing functions, data creation and modification, query and navigation, graphical display, import and use, and visual storage to achieve data accumulation and reuse. The database module includes functions such as data generation, data reading, data storage, data call, data management, and data processing methods.

[0108] Specifically, such as Figure 8 As shown, the database module includes the following functional implementations: Data creation and modification: Based on the characteristics of the data, a reasonable database structure is designed to allow users to create and modify data. Query and navigation: Users can browse parameter data and query parameter data of interest based on keywords. Data graphical display: Data can be graphically displayed through fitting algorithms. Data import and use: The database supports the solver module to call integrated data when performing solution calculations. The specific implementation process is as follows:

[0109] (a) Classify the parametric models and calculation parameters used for each component, establish corresponding standards, extract the empirical coefficients or test line diagrams and tables in the standards used, and form a unified data management file.

[0110] (b) Define the import type of the data file. There are two import types: original format and recognized format. The original format is stored in a table with the file extension .csv. Data points are stored in the table in columns, representing the variable, dependent variable, correction factor, etc.

[0111] (c) Construct the database logic step by step, and assign different attributes and storage locations to each level. The complex system, subsystem, component, and attribute parameter in the fluid network each category has corresponding data and different formats. The data required by the system has global attributes, followed by subsystem data, and the data of components and parameters can be directly reflected in the surface of database management. First, construct the data storage type based on the category of different components, and visualize it in the form of points, curves, and surfaces. Taking the pump as an example, the data structure is shown in Figure 9 .

[0112] (d) Build database data manipulation methods, interface and user interaction methods, and interaction methods between the underlying data and computer files. This includes query, navigation, deletion, and tabular processing.

[0113] (e) Construct the connection and calling method between the database and the fluid network. The database can visually store various performance diagrams, such as the performance diagram of pumps, the performance diagram of tees, the performance diagram of elbows, the performance diagram of reducers, the performance diagram of valves, etc. Given the input conditions from the component model of the fluid network system, the data is called and calculated in the database to obtain the output conditions and transmit them to the network system to complete the calculation of various functions and scenarios. The performance diagram page architecture is shown in Figure 10 .

[0114] (8) Interface module: Supports model exchange with 3D piping layout software through JavaScript scripts to expand the connection relationship between system components in (2). Constructs FMI standard interface to support the interaction between FMU model and external devices to expand the accuracy and versatility of analysis methods. Supports the background call and operation of optimization software through Python commands to build the external optimization process of the system.

[0115] Specifically, it includes the following interface implementations:

[0116] 3D piping model conversion interface: Based on the standard PCF file format for piping stereograms, the interface reads the database of the 3D piping layout software, abstracts the design model into components and connection relationships, converts it into the PCF file format, and writes JavaScript scripts to achieve rapid model conversion, significantly improving modeling efficiency.

[0117] FMU Model Interface: Based on the internationally recognized simulation model interface standard FMI (Functional Mock-up Interface), models from different disciplines are integrated into a single system for design, simulation, and analysis. Simulation models designed using different modeling tools share a unified model description format and data storage method, enabling collaborative simulation of complex systems. Models conforming to the FMI standard are called FMUs (Functional Mock-up Units). The interface supports external interaction with FMU models, including importing FMU models from external simulation software and exporting FMU models for use with external software, thereby extending the accuracy and versatility of analysis methods.

[0118] Command Line Interface: This interface provides functions such as parameter setting, execution, and data output. It can be called using Python and supports scripting in JavaScript, enabling batch simulation and significantly improving simulation speed. The software can also be called from the command line and combined with design optimization software to build an external optimization process.

[0119] The system described in this embodiment uses a parameterized method to quickly establish a nuclear power pipe network system simulation model. By establishing a component library and a working fluid library, appropriate components can be selected according to the actual nuclear power pipe network system to form a connection logic diagram (see Figure 3 ), then set parameters for the nuclear power pipe network system. The corresponding conservation equations are then constructed using a solver for simulation calculations, enabling rapid simulation of complex nuclear power pipe network systems. For complex nuclear power pipe network systems of different disciplines, corresponding components from the component library and corresponding working fluid parameters from the working fluid physical parameter library can be selected, enhancing the versatility of the nuclear power pipe network system modeling and simulation method, ensuring broad applicability.

[0120] The overall technical solution involved in the present invention is a nuclear power plant system-level pipe network simulation and analysis system composed of a pre-processing module, a visual modeling module, a solver module, a post-processing module, a component library module, a working fluid library module, a database module, and an interface module.

[0121] The solver algorithm involved in the present invention establishes a robust and efficient numerical algorithm, solves all control equations through the Newton-Raphson iteration method and the step-by-step iteration method, and integrates synchronous solution and asynchronous solution schemes to solve the fluid network equations describing flow heat transfer, phase change, mixing and multiple source terms, and obtain the distribution of pressure, flow, temperature, etc. in the pipe network system.

[0122] The technical solution for the nuclear power-specific component library and working fluid library involved in this invention integrates the component types and calculation standards of multiple professional manuals, such as "Internal Flow System", GB 50974 "Technical Specification for Fire Water Supply and Fire Hydrant Systems", GB 50084 "Design Specification for Automatic Sprinkler Fire-Extinguishing Systems", NFPA 13 "Standard for the Installation of Sprinkler Systems", Practical Heating and Air Conditioning Design Manual, Crane TP410, "FLOW OF FLUIDS Through Valves, Fittings and Pipe."

[0123] The first key point of the database design scheme involved in this invention lies in its hierarchical structure, which uses a multi-level processing approach to create a clear hierarchy within the database, making the relationships between data more explicit. A second key point lies in the Chebyshev fitting and interpolation methods. Chebyshev fitting involves finding a Chebyshev polynomial within a given range that best approximates a given function. By selecting the appropriate polynomial degree and coefficients, the approximation error between the Chebyshev polynomial and the target function can be minimized.

[0124] The solution described in this embodiment is a nuclear power plant system-level pipeline network simulation and analysis system composed of a pre-processing module, a visual modeling module, a solver module, a post-processing module, a component library module, a working fluid library module, a database module, and an interface module.

[0125] The solver solution in the solution described in this embodiment establishes a robust and efficient numerical algorithm, solves all control equations through the Newton-Raphson iteration method and the step-by-step iteration method, and integrates synchronous solution and asynchronous solution schemes to solve the fluid network equations describing flow heat transfer, phase change, mixing and multiple source terms, and obtains the distribution of pressure, flow, temperature, etc. in the pipe network system.

[0126] The component library and working fluid library technical solutions described in this embodiment integrate component types and calculation standards from multiple professional manuals, including "Internal Flow System", GB 50974 "Technical Specifications for Fire Water Supply and Fire Hydrant Systems", GB 50084 "Design Specifications for Automatic Sprinkler Fire-Extinguishing Systems", NFPA 13 "Standard for the Installation of Sprinkler Systems", Practical Heating and Air Conditioning Design Manual, Crane TP410, "FLOW OF FLUIDS Through Valves, Fittings and Pipe."

[0127] The first key point of the database design scheme described in this embodiment lies in the hierarchical structure of step-by-step processing. This multi-level processing approach creates a clear hierarchy within the database, making the relationships between data more explicit. A second key point lies in the Chebyshev fitting and interpolation methods. Chebyshev fitting involves finding a Chebyshev polynomial within a given range that best approximates a given function. By selecting the appropriate polynomial degree and coefficients, the approximation error between the Chebyshev polynomial and the target function can be minimized.

[0128] It is understandable that in one or more embodiments, an abstract fluid network calculation model can be built using Excel and macro plug-ins.

[0129] In one or more embodiments, the solver module written in C++ language can also be implemented in other programming languages such as Fortran, Python, C#, C++, etc.

[0130] In one or more embodiments, the nuclear power professional manuals and calculation standards integrated in the solutions described in the above embodiments may also integrate other similar professional manuals and calculation standards in the industry.

[0131] In one or more embodiments, the database described in the above embodiments may also employ a flat data model, storing data in a flat structure, rather than using a hierarchical database design approach with step-by-step processing. In a flat data model, all data is organized into a large table, with each row representing a data record and each column representing a data attribute or field. The flat data model is suitable for scenarios with relatively simple data structures and uncomplicated relationships between data. This model is generally effective for small applications or when the data structure is relatively simple.

[0132] In one or more embodiments, the method of converting a three-dimensional design model into a fluid network simulation model in the above embodiment is implemented by JavaScript language, and can also be implemented by other programming languages such as Fortran, Python, C#, C++, etc.

[0133] Example 2:

[0134] The purpose of this embodiment is to provide a simulation analysis method for a system-level pipe network in a nuclear power plant.

[0135] A simulation analysis method for a system-level pipe network of a nuclear power plant, based on the above-mentioned simulation analysis method for a system-level pipe network of a nuclear power plant, comprises:

[0136] Based on the connection relationship of the components in the nuclear power pipe network system to be simulated and the pre-built component models in the component library and working fluid library modules, the nuclear power pipe network system simulation model is constructed; or the pre-built model of the third-party 3D piping layout software is imported through the interface of the interface module; and the external parameter input is received to perform parameter setting of the nuclear power pipe network system;

[0137] Based on the parameterized settings of the nuclear power pipe network system and the preset conservation equations, a modular solution method is used to simulate and solve the nuclear power pipe network system to obtain the pressure, flow and temperature distribution in the nuclear power pipe network system; wherein, the modular solution method specifically includes a main process using the Newton-Raphson iteration method and a branch process based on the results of each iteration of the main process. In further embodiments, the following are also provided:

[0138] An electronic device includes a memory and a processor, and computer instructions stored in the memory and executed by the processor, wherein when the computer instructions are executed by the processor, the method described in Example 2 is performed. For the sake of brevity, no further details are given here.

[0139] It should be understood that in this embodiment, the processor may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), off-the-shelf field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0140] The memory may include a read-only memory and a random access memory, and provides instructions and data to the processor. A portion of the memory may also include a non-volatile random access memory. For example, the memory may also store information about the device type.

[0141] A computer-readable storage medium is used to store computer instructions, and when the computer instructions are executed by a processor, the method described in embodiment 2 is performed.

[0142] The method in Example 2 can be directly implemented and executed by a hardware processor, or by a combination of hardware and software modules within the processor. The software module can be located in a storage medium well-established in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. The storage medium is located in the memory, and the processor reads the information in the memory and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, a detailed description is not given here.

[0143] Those skilled in the art will appreciate that the units, i.e., algorithm steps, of the various examples described in conjunction with this embodiment can be implemented using electronic hardware or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0144] The simulation analysis system and method for the system-level pipe network of a nuclear power plant provided in the above embodiment can be implemented and has broad application prospects.

[0145] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A simulation and analysis system for a system-level pipe network in a nuclear power plant, characterized in that: include: The visual modeling module is used to build a simulation model of the nuclear power pipe network system based on the connection relationship of the components in the nuclear power pipe network system and the pre-built component models; and receive external parameter input to perform parameter settings on the nuclear power pipe network system; A solver module is used to simulate and solve the nuclear power pipe network system using a modular solution method based on the parameter settings of the nuclear power pipe network system and preset conservation equations, thereby obtaining the pressure, flow, and temperature distribution in the nuclear power pipe network system. The modular solution method specifically includes a main process using the Newton-Raphson iteration method and branch processes based on the results of each iteration of the main process. The conservation equations include: conservation of mass, conservation of energy, and conservation of momentum. Conservation of mass: Conservation of momentum: Conservation of Energy: Where, ρ is the fluid density; u is the axial fluid velocity; τ is the time step; Δx is the space step; u is the time step r - radial fluid velocity; K f - flow resistance coefficient; g - acceleration due to gravity; θ - angle between the direction of gravity and the pipe axis; R - inner diameter of the pipe; μ - viscosity; e - total energy per unit mass of fluid; q - heat; h - enthalpy; Q - external energy source; Component library and working fluid library modules are used to integrate professional standard component models including fire protection systems, HVAC systems, traditional piping systems, circulation systems, and control systems; and to build a working fluid physical property parameter library for nuclear power pipeline systems, including general working fluid characteristics, special working fluid physical properties, and solid material properties; The interface module is used to provide a model exchange interface that supports third-party 3D piping layout software.

2. A simulation and analysis system for a system-level pipe network of a nuclear power plant according to claim 1, characterized in that: The main process of adopting the Newton-Raphson iteration method is specifically as follows: adopting the Newton-Raphson iteration method, wherein the iteration variables include the state quantity on each node of the nuclear power pipe network system and the process quantity on each branch; Or, a branch process based on the result of each iteration of the main process, specifically: according to the state quantity and process quantity of each iteration of the main process, the fluid equations including the energy equation, component equation and fluid-solid coupling equation are solved through the branch process.

3. A simulation and analysis system for a system-level pipe network of a nuclear power plant according to claim 1, characterized in that: In the component library and working fluid library modules, the component library includes component models of pipes, elbows, orifice plates, valves, pumps, and containers. The working fluid library includes lubricating oil, boric acid aqueous solution, heavy water, seawater, and ethylene glycol aqueous solution, meeting the working fluid physical property parameters in various application scenarios such as process, diesel engine, water supply and drainage, fire protection, and circulation.

4. A simulation and analysis system for a system-level pipe network of a nuclear power plant according to claim 1, characterized in that: The system further includes a pre-processing module, which is used to perform mathematical parameterized modeling on each type of pipe network element according to its one-dimensional flow characteristics and actual one-dimensional flow physical process; And according to the physical processes and parametric characteristics of different components, they are digitally abstracted and classified into different types of components.

5. The simulation and analysis system for a system-level pipe network of a nuclear power plant according to claim 1, characterized in that: The system further includes a post-processing module, which is used to perform visualization processing and display of the solution results based on the simulation solution results.

6. A simulation and analysis system for a system-level pipe network in a nuclear power plant according to claim 1, characterized in that: The system also includes a database module, which is used to process data from four levels: the nuclear power pipe network system, subsystems, complex component models and specific attribute parameters, so as to create a clear hierarchical structure in the database.

7. A simulation and analysis system for a system-level pipe network of a nuclear power plant according to claim 1, characterized in that: The interface module includes a three-dimensional pipeline model conversion interface, an FMU model interface and a command line calling interface.

8. A simulation analysis method for a system-level pipe network in a nuclear power plant, characterized in that: The simulation analysis system for a system-level pipe network of a nuclear power plant is based on any one of claims 1 to 7, and includes: Based on the connection relationship of the components in the nuclear power pipe network system to be simulated and the pre-built component models in the component library and working fluid library modules, the nuclear power pipe network system simulation model is constructed; or the pre-built model of the third-party 3D piping layout software is imported through the interface of the interface module; and the external parameter input is received to perform parameter setting of the nuclear power pipe network system; Based on the parameterized settings of the nuclear power pipe network system and the preset conservation equations, a modular solution method is used to simulate and solve the nuclear power pipe network system to obtain the pressure, flow and temperature distribution in the nuclear power pipe network system; wherein, the modular solution method specifically includes a main process using the Newton-Raphson iterative method and a branch process based on the results of each iteration of the main process.

9. An electronic device comprising a memory, a processor, and a computer program stored and running on the memory, characterized in that: When the processor executes the program, the simulation analysis method for the system-level pipe network of a nuclear power plant as described in claim 8 is implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the simulation analysis method for a system-level pipe network of a nuclear power plant as described in claim 8 is implemented.

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