Thermal-hydraulic system simulation method and system based on marine condition component library

Abstract

The application provides a kind of marine condition component library-based thermal hydraulic system simulation method and system, related to simulation technical field, which comprises: according to the space topology information of the thermal hydraulic system to be simulated, at least one target component is selected from the marine condition component library containing a plurality of components encapsulated with fluid equations in non-inertial system to establish a simulation model;According to the component parameters and the six-degree-of-freedom motion boundary conditions of the ship, the simulation model is solved simultaneously to obtain the transient thermal hydraulic parameters of the thermal hydraulic system to be simulated under marine conditions;During the simultaneous solution process, the apparent gravity pressure drop source term in the momentum conservation equation is obtained by projecting the three-dimensional body force through the directional unit vector of the target component;The specific enthalpy corresponding to the forward flow and reverse flow of the fluid in the target component is smoothed to obtain the upwind side specific enthalpy in the energy conservation equation.The application improves the accuracy and stability of the transient simulation of the thermal hydraulic system under marine conditions.

Description

Technical Field

[0001] This invention relates to the field of simulation technology, and in particular to a simulation method and system for thermal-hydraulic systems based on a marine condition component library. Background Technology

[0002] The thermal-hydraulic system deployed on ships is affected by ocean conditions such as undulation, roll, and pitch during operation. The rigid body motion of the ship in space causes the velocity field and temperature field of the fluid in the system to exhibit obvious coupling characteristics with the ship's spatial attitude. How to perform high-precision and high-stability transient simulation of thermal-hydraulic systems under ocean conditions is an important technical requirement in this field.

[0003] In related technologies, one-dimensional system thermal-hydraulic programs based on the assumption of a land-based inertial frame are usually used to modify the underlying source code to inject additional force source terms and adopt a condition-based windward differential scheme to directly switch between the specific enthalpy corresponding to forward flow and the specific enthalpy corresponding to reverse flow according to the sign of the transient flow, so as to perform transient simulation of thermal-hydraulic systems under marine conditions.

[0004] However, the one-dimensional flow model described above is not only limited in its simulation accuracy under marine conditions, but also prone to Jacobian matrix singularity when the flow rate frequently crosses zero and reverses due to the alternating inertial force of the sea state. This can lead to a sudden reduction in the integration step size or even global calculation divergence, resulting in poor numerical stability. Summary of the Invention

[0005] This invention provides a simulation method and system for thermal-hydraulic systems based on a marine condition component library, which addresses the shortcomings of poor simulation accuracy and numerical stability in existing technologies, thereby improving the accuracy and stability of transient simulations of thermal-hydraulic systems under marine conditions.

[0006] This invention provides a simulation method for thermal-hydraulic systems based on a marine condition component library, comprising: Based on the spatial topology information of the thermal-hydraulic system to be simulated deployed on the ship, at least one target component is determined from the marine condition component library, and a simulation model of the thermal-hydraulic system to be simulated is established based on the at least one target component; each component in the marine condition component library encapsulates fluid equations in a non-inertial frame; the fluid equations include momentum conservation equations and energy conservation equations; Based on the spatial topology information, the component parameters of each target component are determined; the component parameters include a position vector relative to the motion reference point of the ship and a direction unit vector representing the direction of the component axis; Based on the component parameters and the six-degree-of-freedom motion boundary conditions of the ship, the fluid equations of each target component in the simulation model are solved simultaneously to obtain the transient thermal-hydraulic parameters of the simulated thermal-hydraulic system under marine conditions. In the simultaneous solution process, the apparent gravity pressure drop source term in the momentum conservation equation of each target component is obtained by projecting the three-dimensional bulk force through the direction unit vector of the target component to the one-dimensional axis direction of the target component; the three-dimensional bulk force is determined based on the six-degree-of-freedom motion boundary conditions, the position vector of the target component, and the flow velocity of the fluid; the windward enthalpy in the energy conservation equation of each target component is obtained by smoothing the enthalpy corresponding to the forward flow and the reverse flow of the fluid within the target component using a preset flow tolerance.

[0007] According to the simulation method for a thermal-hydraulic system based on a marine condition component library provided by the present invention, the apparent gravity pressure drop source term in the momentum conservation equation of each target component is calculated based on the following steps: Based on the six-degree-of-freedom motion boundary conditions, determine the translational acceleration, angular velocity, and angular acceleration of the ship; The Euler acceleration is obtained by performing a cross product operation between the angular acceleration and the position vector of the target component. The centrifugal acceleration is obtained by performing a cross product operation between the angular velocity and the position vector of the target component, and then performing a cross product operation between the result of the cross product operation and the angular velocity. The angular velocity is cross-multiplied with the flow velocity of the fluid inside the target component, and the Coriolis acceleration is obtained based on the cross-multiplication result. The total acceleration is obtained by summing the translational acceleration, the Euler acceleration, the centrifugal acceleration, and the Coriolis acceleration. The three-dimensional body force is determined based on the difference between the gravitational acceleration and the total acceleration. The three-dimensional mass force is projected onto the one-dimensional axis direction of the target component through the unit vector of the target component to obtain the apparent gravitational pressure drop source term in the momentum conservation equation of the target component.

[0008] According to the simulation method for a thermal-hydraulic system based on a marine condition component library provided by the present invention, the frictional pressure drop term in the momentum conservation equation of each target component is calculated based on the following steps during the simultaneous solution process: The reference frictional pressure drop is determined based on the friction coefficient along the path, the length, diameter, flow cross-sectional area of ​​the target component, the density of the fluid inside the target component, and the transient mass flow vector. The ship's tilt angle is determined based on the six-degree-of-freedom motion boundary conditions. The dynamic correction factor is determined based on the ship's inclination angle; The reference frictional pressure drop is corrected according to the dynamic correction coefficient to obtain the frictional pressure drop term in the momentum conservation equation of the target component; the dynamic correction coefficient is used to compensate for the calculation deviation of the wall shear force when the ship is in a tilted state.

[0009] According to the present invention, a simulation method for a thermal-hydraulic system based on a marine condition component library is provided, wherein the target component includes a main pipe component; the component parameters of the main pipe component also include the port position vectors of each branch port relative to the central node of the main pipe component; In the process of solving the simultaneous equations, the momentum conservation equations of the target components connected to each of the branch ports are solved simultaneously with the back pressure of the branch ports as the pressure boundary. The back pressure of each branch port is calculated based on the following steps: Based on the six-degree-of-freedom motion boundary conditions, determine the real-time apparent gravitational acceleration; The real-time apparent gravitational acceleration is multiplied by the position vector of each port, and the deflection head of each branch port is determined based on the result of the dot product and the density of the fluid in the main pipe assembly. The back pressure of each branch port is determined based on the pressure of the central node and the deflection head of each branch port.

[0010] According to the present invention, a simulation method for a thermal-hydraulic system based on a marine condition component library is provided, wherein the target component includes a steam-water separator component; In the process of solving the simultaneous equations, the mass flow distribution between the vapor phase outlet and the liquid phase outlet in the mass conservation equation of the steam-water separator assembly, and the outlet specific enthalpy of the vapor phase outlet in the energy conservation equation of the steam-water separator assembly, are all determined based on the transient water carrying capacity of the steam-water separator assembly. The transient water carrying capacity is calculated based on the following steps: Based on the six-degree-of-freedom motion boundary conditions, determine the ship's tilt angle and the gravity deviation of the vertical apparent gravity from the reference gravity. The tilt correction amount is determined based on the tilt sensitivity coefficient and the sine value of the tilt angle; The gravity fluctuation correction amount is determined based on the gravity fluctuation sensitivity coefficient and the ratio between the gravity deviation and the reference gravity. The rated water carrying capacity of the steam-water separator assembly is corrected based on the tilt correction amount and the gravity fluctuation correction amount to obtain the transient water carrying capacity.

[0011] According to the present invention, a simulation method for a thermal-hydraulic system based on a marine condition component library is provided, wherein the target component includes a steam generator component, and the fluid equation of the steam generator component further includes a pressure conservation equation and a heat transfer coefficient equation. In the process of solving the simultaneous equations, the transient pressure change rate in the pressure conservation equation and the dynamic total heat transfer coefficient in the heat transfer coefficient equation are calculated based on the following steps: The first mass change term is determined based on the liquid phase volume of the steam generator assembly, the partial derivative of the saturated liquid density with respect to the saturated liquid enthalpy, and the rate of change of the saturated liquid enthalpy. The second mass change term is determined based on the vapor phase volume of the steam generator assembly, the partial derivative of the saturated vapor density with respect to the saturated vapor enthalpy, and the rate of change of the saturated vapor enthalpy. The transient pressure change rate is calculated based on the inlet mass flow rate, outlet mass flow rate, first mass change term, second mass change term, the product of the liquid phase volume and the partial derivative of the saturated liquid density with respect to pressure, and the product of the vapor phase volume and the partial derivative of the saturated vapor density with respect to pressure of the steam generator assembly. The ship's tilt angle is determined based on the six-degree-of-freedom motion boundary conditions. The heat transfer area attenuation function value is determined based on the ship's inclination angle and the liquid level in the steam generator assembly. The dynamic overall heat transfer coefficient is determined based on the rated overall heat transfer coefficient, the heat transfer area decay function value, and the ratio between the real-time mass flow rate of the primary side and the rated mass flow rate of the primary side.

[0012] According to the present invention, a simulation method for a thermal-hydraulic system based on a marine condition component library is provided, wherein the target component includes a condenser component; the fluid equation of the condenser component further includes a liquid level differential equation. In the process of solving the simultaneous equations, the rate of change of hot well liquid level in the liquid level differential equation is calculated based on the following steps: The liquid phase volume expansion correction is determined based on the transient pressure change rate, liquid phase volume, and partial derivative of liquid phase density with respect to pressure within the condenser assembly. The net change in the mass of the hot well is determined based on the difference between the condensation and outflow of the condenser assembly and the liquid phase volume expansion correction. The rate of change of hot well liquid level is determined based on the net change in the mass of the hot well, the liquid phase density of the fluid in the condenser assembly, and the cross-sectional area of ​​the hot well.

[0013] According to the present invention, a simulation method for a thermal-hydraulic system based on a marine condition component library is provided, wherein the target component includes a pump component; the fluid equation of the pump component also includes an effective head equation; In the process of solving the simultaneous equations, the effective pressure head in the effective pressure head equation is calculated based on the following steps: The steady-state head of the pump assembly is determined based on the characteristic curve fitting coefficient, volumetric flow rate, and transient rotational angular velocity of the pump assembly. Based on the six-degree-of-freedom motion boundary conditions, determine the apparent acceleration of the ship; The dynamic head compensation term is determined based on the directional unit vector of the pump assembly, the apparent acceleration, and the density of the fluid within the pump assembly. The effective pressure head is determined based on the steady-state pressure head and the dynamic pressure head compensation term.

[0014] According to the present invention, a simulation method for a thermal-hydraulic system based on a marine condition component library is provided, wherein the target component includes a steam turbine component; the fluid equation of the steam turbine component also includes a work equation; In the process of solving the simultaneous equations, the work term in the work equation is calculated based on the following steps: Based on the six-degree-of-freedom motion boundary conditions, determine the transient yaw rate of the ship; The rotor spin angular velocity of the turbine assembly is cross-multiplied with the transient oscillation angular velocity, and the transient gyro torque is determined based on the cross-multiplication result and the rotor moment of inertia of the turbine assembly. Based on the transient gyro torque, determine the additional mechanical frictional power consumption of the bearing system acting on the turbine assembly; The theoretical output power of the turbine assembly is determined based on the inlet steam mass flow rate, isentropic enthalpy drop, and isentropic efficiency of the turbine assembly. The work item is determined based on the difference between the theoretical output power and the additional mechanical friction power consumption.

[0015] This invention also provides a thermal-hydraulic system simulation system based on a marine condition component library, comprising: The model building module is used to determine at least one target component from the marine condition component library based on the spatial topology information of the thermal-hydraulic system to be simulated deployed on the ship, and to establish a simulation model of the thermal-hydraulic system to be simulated based on the at least one target component; each component in the marine condition component library encapsulates fluid equations in a non-inertial frame; the fluid equations include momentum conservation equations and energy conservation equations; The parameter configuration module is used to determine the component parameters of each target component based on the spatial topology information; the component parameters include a position vector relative to the motion reference point of the ship and a direction unit vector representing the direction of the component axis; The simulation module is used to solve the fluid equations of each target component in the simulation model simultaneously based on the component parameters and the six-degree-of-freedom motion boundary conditions of the ship, so as to obtain the transient thermal-hydraulic parameters of the simulated thermal-hydraulic system under marine conditions. In the simultaneous solution process, the apparent gravity pressure drop source term in the momentum conservation equation of each target component is obtained by projecting the three-dimensional bulk force through the direction unit vector of the target component to the one-dimensional axis direction of the target component; the three-dimensional bulk force is determined based on the six-degree-of-freedom motion boundary conditions, the position vector of the target component, and the flow velocity of the fluid; the windward enthalpy in the energy conservation equation of each target component is obtained by smoothing the enthalpy corresponding to the forward flow and the reverse flow of the fluid within the target component using a preset flow tolerance.

[0016] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the thermal-hydraulic system simulation method based on the marine condition component library as described above.

[0017] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the thermal-hydraulic system simulation method based on the marine condition component library as described above.

[0018] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the thermal-hydraulic system simulation method based on the marine condition component library as described above.

[0019] The present invention provides a simulation method and system for thermal-hydraulic systems based on a marine condition component library. This method establishes a simulation model by identifying target components from a marine condition component library containing fluid equations in a non-inertial frame. Each target component is assigned a position vector and a unit direction vector, enabling the simulation model to adapt to different system spatial layouts in a modular and reusable manner, without requiring repeated modifications to the underlying code for different layouts. During the simultaneous solution process, the apparent gravity pressure drop source term is obtained by projecting the three-dimensional body forces determined based on the six-degree-of-freedom boundary conditions, position vectors, and flow velocity onto the one-dimensional axial direction via the unit direction vector. This allows one-dimensional fluid equations to accurately perceive the differentiated mechanical effects of ship motion in three-dimensional space on target components at different spatial positions and with different axial orientations, improving the simulation accuracy of transient thermo-hydraulic parameters under marine conditions. Furthermore, by using preset flow tolerances to smooth the specific enthalpy corresponding to forward flow and reverse flow to obtain the windward specific enthalpy, the Jacobian matrix singularity problem caused by the step jump of derivatives when the flow frequently crosses zero and reverses is eliminated, ensuring the numerical stability of the simultaneous solution process under extreme sea state oscillations, thereby improving the accuracy and stability of transient simulation of thermo-hydraulic systems under marine conditions. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a flowchart illustrating the simulation method for thermal-hydraulic systems based on a marine condition component library provided by the present invention.

[0022] Figure 2 This is a schematic diagram of the additional inertial force on the fluid micro-clusters within the component under six degrees of freedom in marine conditions, as provided by the present invention.

[0023] Figure 3 This is a schematic diagram of the smooth transition result of the windward enthalpy specificity provided by the present invention.

[0024] Figure 4 This is a schematic diagram of the verification model for the static tilting experiment of a single-phase natural circulation micro-loop provided by the present invention.

[0025] Figure 5 This is a schematic diagram of the temperature difference between the hot and cold sections as a function of heating power under steady-state tilting conditions provided by the present invention.

[0026] Figure 6 This is a schematic diagram of the prediction error distribution under steady-state tilting conditions provided by the present invention.

[0027] Figure 7 This is a schematic diagram of the layout of the single-phase forced cycle test bench under dynamic swing conditions provided by the present invention.

[0028] Figure 8 This is a schematic diagram comparing the transient response of forced circulation mass flow rate under a 15-degree swing angle condition with a 7.5-second cycle, as provided by the present invention.

[0029] Figure 9 This is a schematic diagram comparing the transient response of forced cyclic mass flow rate under a 10-second cycle at a 15-degree swing angle, as provided by the present invention.

[0030] Figure 10 This is a schematic diagram comparing the transient response of forced circulation mass flow rate under different amplitudes in a 10-second periodic tilting condition, as provided by the present invention.

[0031] Figure 11 This is a schematic diagram of the secondary loop system of marine nuclear power provided by the present invention.

[0032] Figure 12 This is one of the schematic diagrams of the transient evolution curve of the main mass flow rate of a two-loop system under fluctuating single-degree-of-freedom conditions provided by the present invention.

[0033] Figure 13 This is the second schematic diagram of the transient evolution curve of the main mass flow rate of a two-loop system under fluctuating single-degree-of-freedom conditions provided by the present invention.

[0034] Figure 14 This is a schematic diagram of the transient evolution curve of the main mass flow rate of a two-loop system under a single degree of freedom of tilting, provided by the present invention.

[0035] Figure 15 This is a schematic diagram of the transient evolution curve of the main mass flow rate of a two-loop system under the single-degree-of-freedom rolling condition provided by the present invention.

[0036] Figure 16 This is a schematic diagram of the broadband oscillation evolution of the main mass flow rate of a two-loop system under multi-degree-of-freedom sea conditions provided by the present invention.

[0037] Figure 17 This is a schematic diagram of the structure of the thermal-hydraulic system simulation system based on the marine condition component library provided by the present invention.

[0038] Figure 18 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0040] All actions involving the acquisition of signal information or data in this application are carried out in accordance with the relevant data protection laws and policies of the country where the application is located, and with the authorization granted by the owner of the relevant device.

[0041] In the field of marine nuclear power and floating nuclear power plants, the simulation problems of transient flow and heat transfer of fluids in pipes under non-inertial frames, especially the problems involving solving the mass, momentum and energy control equations under complex dynamic boundaries, can be mainly divided into two categories: one is the traditional System Thermal Hydraulics (STH) program numerical simulation method, and the other is the component modeling method based on multiphysics non-causal modeling language.

[0042] For numerical simulation methods of system thermal-hydraulic programs, the most commonly used methods in current engineering practice are one-dimensional system thermal-hydraulic programs based on the finite volume difference method. Typical programs include the Reactor Excursion and Leak Analysis Program (RELAP5), the Analysis of Thermal-hydraulics of Leaks and Transients (ATHLET), and the Code for Analysis of Thermal-Hydraulics during Accidents in Reactors (CATHARE). When applied to marine conditional loop flow heat transfer problems, this type of method typically involves the following steps: First, establish a geometric topology model of the entire system's one-dimensional nodes and flow channel network, i.e., the control volume node model of the system to be solved; second, derive the correction terms of the fluid momentum equation in a non-inertial coordinate system; third, embed three-dimensional additional inertial force source terms in the program's underlying layer using programming languages ​​such as Formula Translation (Fortran) through hard coding; then, input fluid property parameters, set initial steady-state conditions, and dynamic boundary conditions such as sea state acceleration and angles for sinusoidal fluctuations; next, use an integrator to obtain transient velocity, pressure, and temperature results through numerical integration; finally, extract transient parameters at specified devices or nodes from the post-processed data for safety margin analysis.

[0043] This type of method possesses advantages such as good system-level macroscopic conservation, mature engineering applications, and high reliability of long-term transient calculation results. Therefore, a large number of studies on the operating characteristics of marine reactors use traditional system thermal-hydraulic programs as benchmark tools. However, the underlying program of this type of method adopts a rigid architecture and closed code. The overall development process requires multiple steps, including control volume node partitioning, derivation of additional forces in the underlying momentum equation, hard-coded embedding of source code, and semi-implicit integral solving. It is highly dependent on the underlying code structure, resulting in extremely high secondary development costs. When it is necessary to customize marine-specific components or extend interdisciplinary physical phenomena, it lacks flexibility and versatility. Furthermore, the underlying control equations are mostly constructed based on the assumption of a land-based steady-state inertial frame, which has poor adaptability to complex alternating frequency bands and cannot smoothly transition when dealing with high-frequency inertial force impacts. In addition, when encountering When extreme sea state disturbances cause low-velocity oscillations or frequent flow reversals, Jacobian matrix singularities are prone to occur, leading to a sharp reduction in the computational step size of the variable-step solver or even global divergence and collapse. This makes it difficult to balance the response accuracy of high-frequency alternating boundaries with global solution stability. Furthermore, the solver has poor scalability for strongly coupled interdisciplinary problems such as rotor mechanical dynamics losses and deterioration of two-phase liquid surface tilt. Especially in scenarios with severe flow fluctuations under extreme sea states, relying solely on point-by-point modifications to traditional system thermal-hydraulic programs incurs high code intrusion costs, making it difficult to balance physical model expansion and multi-condition adaptability. Therefore, traditional system thermal-hydraulic programs are more suitable for macroscopic benchmark verification than for building a unified component library solution framework that balances flexible reconfiguration, minimal modification, and divergence prevention.

[0044] For component modeling methods, related technologies are usually based on object-oriented non-causal modeling languages ​​such as Modelica, directly calling open-source or commercial standard fluid component libraries, such as the Modelica.Fluid standard fluid library. The system model is built by dragging and dropping blocks. The general process is as follows: calling basic components such as pipes, pumps, valves and heat exchangers from the standard library; inputting fluid physical property parameters and static geometric parameters; realizing the topological closed loop of system mass, momentum and energy through graphical port connections; setting conventional static boundary conditions such as pressure, temperature and flow rate; and using variable step size solvers such as Differential Algebraic System Solver (DASSL) to calculate the transient evolution of the system.

[0045] While this type of method offers high efficiency and flexibility in simulating stable land-based systems, it is essentially a land-based inertial frame model. The underlying mass, momentum, and energy control equations of the standard components lack provisions for dynamic gravity vectors and additional momentum source terms for the six degrees of freedom in space. When facing high-frequency oceanic fluctuations, the standard components cannot perceive the complex spatial rigid body motion boundaries. Furthermore, the standard fluid component library itself has several shortcomings. When handling low driving heads and frequent flow reversals, it lacks continuity and smoothness guarantees. Relying solely on standard components can easily lead to implicit integrators getting stuck in nonlinear iterative dead loops or local divergence failures. For example, when constructing a single-phase natural circulation system with a 3-meter height difference in the system frame, standard pipe diameters of 20 mm, and core equipment such as steam generators with a compact volume of only 0.05 cubic meters using standard fluid components, the rigidity of the nonlinear algebraic equations and the coarse flow direction switching mechanism in the standard library often lead to convergence difficulties and computational speed bottlenecks in the simulation. This indicates that standard component technology suffers from poor numerical stability and easy divergence when dealing with such sensitive systems, and there is still a lack of highly robust technical solutions suitable for complex marine operating conditions.

[0046] Furthermore, there are also improvement schemes for marine conditions in related technologies, such as the scheme of custom-developing some adaptive fluid pipes for marine conditions. These are mostly concentrated in single-phase natural circulation pipelines or specific simple heat transfer scenarios. Common methods include: rewriting the momentum partial differential equation, explicitly introducing some additional inertial force source terms such as translational and oscillating Euler forces; defining direction vectors inside the component model to extract local alternating pressure drop and flow fluctuations; and performing basic absolute value processing or conditional judgment processing on parameters such as enthalpy between staggered grids to deal with fluid backflow.

[0047] However, under extreme sea conditions, the improved scheme frequently experiences zero flow and low velocity oscillations. Conventional upwind difference schemes and conditional judgment switching mechanisms can cause abrupt changes in the derivatives of the flow variables, easily leading to Jacobian matrix singularities and computational divergence collapse, lacking a fundamental continuous regularization numerical guarantee mechanism. Furthermore, in the core heterogeneous equipment areas such as steam-water separators and steam turbines, conventional fluid components struggle to account for the microscopic separation degradation caused by three-dimensional tilting and the additional frictional power consumption of rigid body dynamics, making it difficult to achieve deep physical constraints across disciplines. In addition, under high-frequency, multi-degree-of-freedom coupled sea conditions, the component architecture, which relies heavily on standard library repairs, exhibits excessive rigidity, and its underlying equations lack the ability to express complex nonlinear flow heat transfer coupling behavior and computational robustness. Moreover, in the absence of specific marine condition-specific components, the time and debugging costs required to forcibly simulate the two-phase evolution inside marine equipment using complex conditional judgments are high, making it difficult to demonstrate the advantages of modular modeling. This results in insufficient model fidelity and scalability, making it difficult to directly meet the high-efficiency multiphysics simulation requirements of marine nuclear energy systems.

[0048] Therefore, how to enable the simulation model to perceive the differentiated effects of the rigid body motion of the ship in three-dimensional space on the fluid forces in equipment with different spatial positions and different axial orientations in the system, and to maintain the stability of the numerical solution when the flow rate frequently crosses zero and reverses due to the inertial force caused by the alternating sea state, has become a technical problem that urgently needs to be solved in this field.

[0049] To address the limitations of one-dimensional flow models in marine conditions and the problems of computational divergence and poor numerical stability caused by the singularity of the Jacobian matrix when the flow rate frequently crosses zero and reverses, this application adopts a structured modeling paradigm based on non-causal equation language. By directly encapsulating the fluid equations in non-inertial frames into the physical descriptions of each component in the marine condition component library, it achieves a deep integration of numerical calculation methods and software engineering componentization paradigm, reduces the development threshold and maintenance difficulty of multidisciplinary cross-modeling of marine nuclear power systems, and provides a simulation technology that can perform high-precision and high-stability transient simulation of thermal-hydraulic systems under marine conditions.

[0050] Figure 1 This is a flowchart illustrating the simulation method for thermal-hydraulic systems based on a marine condition component library provided by the present invention.

[0051] It should be noted that the execution subject of this method can be a server, a terminal device, or a processor in an electronic device with data processing capabilities; this application embodiment does not limit this. For example... Figure 1 As shown, the method includes the following steps: Step 110: Based on the spatial topology information of the thermal-hydraulic system to be simulated deployed on the ship, at least one target component is determined from the marine condition component library, and a simulation model of the thermal-hydraulic system to be simulated is established based on the at least one target component; each component in the marine condition component library encapsulates fluid equations in a non-inertial frame; the fluid equations include momentum conservation equations and energy conservation equations.

[0052] The thermal-hydraulic system to be simulated refers to a flow heat transfer system deployed on a ship that requires simulation analysis of its thermal-hydraulic characteristics under marine conditions. For example, the thermal-hydraulic system to be simulated can be a marine nuclear power secondary loop system, a marine nuclear power primary loop steam supply system, or other loop systems under marine conditions such as a miniature modular floating reactor, a marine high-temperature gas-cooled reactor, a marine-condition liquid metal-cooled fast reactor, or a low-pressure marine floating molten salt reactor. The fluid medium within the thermal-hydraulic system to be simulated can be water and steam, or liquid lead-bismuth alloy, liquid sodium, supercritical carbon dioxide, helium, or organic working fluids, etc. This application does not limit the specific type of thermal-hydraulic system to be simulated or the fluid medium.

[0053] Spatial topology information is used to describe the deployment of the simulated thermal-hydraulic system on the ship. It may include the types of equipment included in the simulated thermal-hydraulic system, the connection relationships between the equipment, and the spatial position and axis orientation of each equipment in the ship's coordinate system. For example, spatial topology information can be obtained from the ship's general layout drawings, three-dimensional design model, or design specifications. This application embodiment does not limit the source of the spatial topology information.

[0054] The Ocean Conditions Component Library refers to a pre-built component library containing multiple components adapted to ocean conditions. Each component in the Ocean Conditions Component Library is encapsulated as an independent physical model unit, and each component encapsulates fluid equations in a non-inertial frame.

[0055] It should be noted that a non-inertial frame of reference refers to a reference frame fixedly connected to the ship and moving with it. Because ships experience undulations, rolls, and pitches under ocean conditions, the reference frame fixed to the ship experiences translational acceleration and rotational motion relative to the ground-based inertial frame. When describing fluid motion in this non-inertial frame, the fluid equations need to account for the additional inertial forces introduced by the ship's motion. Therefore, unlike conventional fluid components based on the assumption of a land-based steady-state inertial frame, each component in the ocean condition component library in this embodiment reserves the ability to perceive the ship's spatial motion from the underlying differential equation level. For example, the ocean condition component library can be built based on a non-causal multiphysics modeling language, such as Modelica. The resulting component library can be called and compiled in a modeling platform that supports the corresponding language specifications; this embodiment does not limit this.

[0056] The components in the marine condition component library can include at least one of the following model components specifically designed for marine conditions, developed based on the underlying differential equations: piping components, steam generator components, header components, turbine components, steam-water separator components, condenser components, deaerator components, and pump components. Each component can be replaced or embedded into the thermal model at any time according to simulation requirements, achieving plug-and-play functionality and adapting to the reusability requirements of different system layouts and engineering scenarios.

[0057] The fluid equation refers to the control equation encapsulated inside the component and used to describe the fluid motion and energy transfer laws within the component. The fluid equation includes at least the momentum conservation equation and the energy conservation equation. For example, the fluid equation may also include the mass conservation equation, as well as other equations for specific devices. This application does not limit this.

[0058] The momentum conservation equation describes the transient momentum balance of the fluid within the component. It is reconstructed from the underlying partial differential conservation equation by performing force analysis on the fluid micro-elements in a non-inertial frame. Specifically, unlike the conventional momentum equation based on the assumption of a land-based steady-state inertial frame and only considering fixed gravity terms, the momentum conservation equation in this embodiment is constructed by balancing the transient momentum change rate of the fluid within the component with the nodal pressure difference, frictional pressure drop, and apparent gravity pressure drop source terms at both ends of the component, using a non-inertial reference frame fixedly connected to the ship as the reference. The apparent gravity pressure drop source terms are explicitly embedded into the control equations during equation reconstruction, and a three-dimensional body force interface associated with the ship's six-degree-of-freedom motion and a position vector and direction unit vector interface associated with the component's spatial arrangement are reserved. This allows the component to reduce the three-dimensional spatial force characteristics to a one-dimensional axial direction for momentum balance calculation when solving simultaneous equations, based on the real-time input six-degree-of-freedom motion boundary conditions. In other words, the momentum conservation equations of each component in the marine condition component library are designed to have the ability to perceive the rigid body motion of the ship in space from the mathematical mechanism level when they are encapsulated, rather than simply making repairs to the existing land-based equations by adding external signals.

[0059] The energy conservation equation is used to describe the transient evolution of energy parameters such as specific enthalpy of fluid within the component. It is obtained by discretizing the control volume of the component using the finite volume method and establishing a transient energy differential equation for specific enthalpy for each control volume. Specifically, a staggered grid discretization architecture can be used to spatially discretize the components. Scalars such as pressure and specific enthalpy are placed at the grid center, while flow variables such as mass flow rate are placed at the grid boundaries. For each spatially discretized node, an energy conservation equation is constructed by balancing the transient rate of change of the node's specific enthalpy with the convective enthalpy flow flowing into the control volume and the external heating rate. The convective enthalpy flow is determined by the transient mass flow rate and the windward specific enthalpy. Unlike conventional energy equations that directly step-switch between the specific enthalpy corresponding to forward flow and the specific enthalpy corresponding to reverse flow based on conditional judgment, the energy conservation equation in this embodiment defines the windward specific enthalpy as a continuous regularized form smoothed using a preset flow tolerance during equation construction. This ensures that the flow variables in the energy conservation equation maintain continuous derivatives when the flow rate reverses at zero crossings. In other words, the energy conservation equation incorporates a continuity guarantee for frequent flow reversals under ocean conditions from a mathematical mechanism level during encapsulation, rather than relying on post-solution corrections during the solution phase.

[0060] Optionally, in practical applications, the appropriate type of component can be selected from the marine condition component library as the target component based on the type of equipment described by the spatial topology information of the thermal-hydraulic system to be simulated on the ship. Then, according to the connection relationship described by the spatial topology information, the target components can be connected by port connections to realize the topological closed loop of the system's mass, momentum and energy transfer path, thereby establishing a simulation model of the thermal-hydraulic system to be simulated.

[0061] For example, a simulation model can be created in a graphical modeling environment by dragging and dropping components and connecting ports. This application embodiment does not limit the specific method of creating the simulation model.

[0062] Step 120: Determine the component parameters of each target component based on the spatial topology information; the component parameters include the position vector relative to the motion reference point of the ship and the direction unit vector representing the direction of the component axis.

[0063] The motion reference point refers to the reference benchmark point for the rigid body motion of the ship in space. For example, it can be the center of gravity of the ship, the center of sway of the ship, or other pre-set benchmark points. This application does not limit this.

[0064] The position vector refers to the vector formed by the three-dimensional spatial coordinates of the target component relative to the motion reference point, used to characterize the spatial position of the target component in the ship's coordinate system. It is understandable that for the same ship motion, the additional inertial forces experienced by target components at different spatial positions are different. For example, components farther from the center of sway experience stronger centrifugal and tangential acceleration during swaying motion. Therefore, the position vector is a key parameter for characterizing the differentiated forces experienced by components.

[0065] The directional unit vector refers to the unit vector that characterizes the axial direction of the target component, and is used to characterize the direction of one-dimensional fluid flow within the target component. For example, for a vertically arranged riser, its directional unit vector is along the vertical direction of the hull; for a horizontally arranged pipe section, its directional unit vector is along the length or width of the ship.

[0066] Optionally, after constructing the simulation model, the corresponding position vector and direction unit vector can be configured for each target component based on the spatial position coordinates and axis orientation of each device in the spatial topology information.

[0067] Step 130: Based on the component parameters and the six-degree-of-freedom motion boundary conditions of the ship, solve the fluid equations of each target component in the simulation model simultaneously to obtain the transient thermal-hydraulic parameters of the simulated thermal-hydraulic system under marine conditions.

[0068] The six-degree-of-freedom (DOF) motion boundary conditions refer to the boundary conditions used to describe the six degrees of freedom motion of a ship. The six degrees of freedom motion of a ship include heave, roll, pitch, yaw, surge, and sway. For example, the six-degree-of-freedom motion boundary conditions may include the motion time history information of the ship in each degree of freedom, such as translational acceleration time history, attitude angle time history, angular velocity time history, and angular acceleration time history. The six-degree-of-freedom motion boundary conditions can be set as a single-degree-of-freedom sinusoidal motion, or as a composite motion of multiple degrees of freedom superimposed at the same frequency or asynchronously. They can also use motion data generated from measured sea state data or wave spectra. This application embodiment does not limit this.

[0069] Optionally, after obtaining the component parameters and the six-degree-of-freedom motion boundary conditions of the ship, the six-degree-of-freedom motion boundary conditions can be injected into the boundary of the simulation model. Each target component can perceive the mechanical effects of the ship's motion in its spatial position and along its axis based on its own position vector and direction unit vector, thereby solving the fluid equations of each target component in the simulation model simultaneously.

[0070] It should be noted that simultaneous solution refers to assembling the fluid equations of each target component in the simulation model into a unified system of nonlinear differential-algebraic equations according to the port connection relationship, and then solving this system of equations as a whole. In terms of spatial discretization, the staggered mesh discretization architecture of the Finite Volume Method (FVM) can be used to discretize the fluid equations of each target component, placing scalars such as pressure and specific enthalpy at the mesh center and fluid variables such as mass flow rate at the mesh boundaries. In other embodiments, other mesh discretization formats can be used, and the computational problem under high-frequency inertial forced oscillations can be eliminated by introducing momentum interpolation. Alternatively, other one-dimensional manifold discretization strategies such as the finite difference method or the finite element method can be used to discretize the fluid equations. This application does not limit these methods. For time integration, a variable-step implicit differential-algebraic system solver (DASSL) can be used to advance the solution. Depending on the specific real-time or rigid solution requirements, it can also be switched to other implicit or semi-implicit advanced ordinary differential or algebraic equation solvers such as the C-language Variable-coefficient Ordinary Differential Equation solver (CVODE), Radau IIA type implicit Runge-Kutta solver (Radau IIA), and Explicit Singly Diagonally Implicit Runge-Kutta solver (ESDIRK). It can also be switched to the fixed-step first-order Euler algorithm or the fourth-order Runge-Kutta (RK4) explicit or semi-implicit discretization algorithm. The embodiments of this application do not limit the specific solution algorithm.

[0071] Transient thermo-hydraulic parameters refer to the thermo-hydraulic parameters of the simulated thermo-hydraulic system that evolve over time under marine conditions. These parameters may include, for example, at least one of the following: transient mass flow rate, transient pressure, transient temperature, transient specific enthalpy of the fluid within each target component, and parameters such as liquid level, head, and output power of the equipment. The obtained transient thermo-hydraulic parameters can be used for nonlinear flow oscillation mechanism analysis, safety margin assessment, three-dimensional spatial topology optimization, anti-sway control strategy design, and limit operation boundary exploration of systems under marine conditions. This application does not limit the specific types and uses of transient thermo-hydraulic parameters.

[0072] In the simultaneous solution process, the apparent gravitational pressure drop source term in the momentum conservation equation of each target component is obtained by projecting the three-dimensional bulk force through the direction unit vector of the target component to the one-dimensional axis direction of the target component.

[0073] Figure 2 This is a schematic diagram of the additional inertial forces acting on fluid micro-clusters within a component under six degrees of freedom in marine conditions, as provided by the present invention. Figure 2 (a) in the diagram is a schematic diagram of the distribution of the six degrees of freedom of ocean conditions; Figure 2 (b) is a schematic diagram showing the additional inertial force acting on the fluid micro-elements within the component. The angular velocity of the ship; It is a translational inertial force, specifically caused by the ship's translational acceleration; For Coriolis force; This is the standard gravitational acceleration; The vertical (Z-axis) translational acceleration; This refers to the position vector of the target component relative to the motion reference point, or the position vector of the fluid micro-element relative to the motion reference point. The instantaneous sway angle of a ship around a certain coordinate axis, also known as the heel angle. The direction unit vector of the target component; It is centrifugal force.

[0074] like Figure 2 As shown, the six-degree-of-freedom motion of a ship introduces high-frequency, nonlinear three-dimensional alternating additional inertial forces and gravitational field distortions into the fluid micro-elements within the components. The actual volume force on the fluid micro-elements deviates from the standard gravity, forming a three-dimensional pervasive force.

[0075] The three-dimensional body force refers to the equivalent volume force vector acting on a unit mass of fluid within a component in a non-inertial frame. It is composed of standard gravity and the additional inertial force introduced by ship motion, and can also be understood as the apparent gravitational acceleration vector under marine conditions. The three-dimensional body force is determined based on the six-degree-of-freedom motion boundary conditions, the position vector of the target component, and the fluid velocity: the six-degree-of-freedom motion boundary conditions determine the overall shape of the additional inertial force introduced by ship motion; the position vector of the target component determines the magnitude of the spatial position-related component of this additional inertial force, thus causing the target component at different spatial positions to experience differentiated body forces; the fluid velocity refers to the speed of the fluid within the target component relative to the ship, which determines the component of the additional inertial force related to the relative motion of the fluid. This application does not limit the specific calculation method of the three-dimensional body force, as long as it can characterize the equivalent volume force acting on the fluid in a non-inertial frame based on the six-degree-of-freedom motion boundary conditions, position vector, and flow velocity.

[0076] Projection refers to the operation of reducing a three-dimensional vector to a one-dimensional axis direction using a unit direction vector, which can be achieved through dot product. For example, the momentum conservation equation for any target component can be expressed as the following transient momentum balance differential equation: ; in, The length of the target component, Let be the cross-sectional area of ​​the target component. The rate of change of mass flow rate over time. The pressure difference between the nodes at both ends of the target component. This is the frictional pressure drop term. This is the apparent gravitational pressure drop source term.

[0077] Understandably, by projecting the three-dimensional body forces onto the one-dimensional axial direction via a unit vector, the three-dimensional spatial mechanical characteristics are strictly mapped onto the one-dimensional solution manifold. This retains the computational efficiency advantage of one-dimensional system-level simulation while enabling the one-dimensional flow model to sensitively and accurately perceive the three-dimensional spatial force changes generated by the swaying and undulating of the fluid with the hull. For example, for risers arranged vertically along the hull, the vertical additional inertial force generated by the undulating motion will be fully projected as an axial pressure drop; while for horizontally arranged pipe sections, the projected component of the same motion approaches zero, thus realistically reproducing the differentiated responses of components with different axial orientations to the same sea state motion.

[0078] In the process of solving the simultaneous equations, the windward enthalpy in the energy conservation equation of each target component is obtained by smoothing the enthalpy corresponding to the forward flow and the reverse flow of the fluid in the target component using a preset flow tolerance.

[0079] Among them, the windward enthalpy refers to the specific enthalpy taken from the upstream side according to the flow direction in the energy conservation equation: when the fluid in the component flows in the forward direction, the windward enthalpy should be the specific enthalpy corresponding to the forward flow, that is, the specific enthalpy of the upstream node when the flow is forward; when the fluid flows in the reverse direction, the windward enthalpy should be the specific enthalpy corresponding to the reverse flow, that is, the specific enthalpy of the upstream node when the flow is reverse.

[0080] Understandably, under marine conditions, alternating additional inertial forces can cause the mass flow rate within the component to frequently reverse near zero. If a step switching is applied to the enthalpy on the windward side when the flow direction changes, it will cause a step change in the derivative of the flow variable. This application employs a smoothing process to ensure that when the transient mass flow rate is within the transition range defined by a preset flow tolerance, the enthalpy on the windward side transitions continuously and smoothly between the enthalpy corresponding to the forward flow and the enthalpy corresponding to the reverse flow.

[0081] Here, the preset flow tolerance refers to a pre-set, minimal flow tolerance used to define the smooth transition range. For example, the preset flow tolerance can be taken as... The specific value of kg / s can be set according to the flow rate of the system and the accuracy requirements of the solution. This application does not limit this.

[0082] For example, the energy conservation equation and the windward enthalpy of any target component can be expressed as: ; ; in, The total volume of the target component. The number of spatially discrete nodes of the target component. For nodes within the target component The density of the fluid at that location, For nodes within the target component Transient specific enthalpy at that point The transient mass flow rate of the target component. For nodes within the target component The corresponding external heating rate within the control volume; For nodes within the target component Enthalpy on the windward side This represents the specific enthalpy corresponding to the forward flow of the fluid. The specific enthalpy corresponding to reverse fluid flow. To preset the flow tolerance, The continuous regularization operator used for smoothing can be, for example, a continuous regularization step size operator, or a smooth piecewise function that forces derivative matching constraints within the flow tolerance range, a continuous approximation function based on hyperbolic asymptotes, or a higher-order smooth deformation based on arctangent function or sigmoid function. As long as it can achieve a smooth transition of the windward enthalpy within the regularization transition range, the embodiments of this application are not limited in this regard.

[0083] Figure 3 This is a schematic diagram of the smooth transition of specific enthalpy on the windward side provided by the present invention. For example... Figure 3 As shown, when sea state oscillations cause the transient mass flow rate to frequently reverse near zero, the enthalpy on the windward side smoothly transitions from the enthalpy corresponding to the forward flow to the enthalpy corresponding to the reverse flow within a switching zone defined by a preset flow rate tolerance. This switching zone exhibits continuity in both first and second derivatives, mathematically eliminating the abrupt change in derivatives when the flow direction reverses. This eliminates the root cause of the singularity in the Jacobian matrix of the nonlinear algebraic equation system, avoiding the implicit integral solver's tendency to experience sudden step size reduction, trial-step dead loops, or global divergence collapse when handling high-frequency ocean transients, thus endowing the simulation model with high numerical robustness under extreme sea state oscillations.

[0084] Furthermore, the method provided in this application embodiment has good scalability in terms of application objects, fluid media, and deployment forms. In terms of application objects, in addition to marine nuclear power secondary loop systems, the modeling and solution logic described in this application embodiment can also be extended to the complete evolution simulation of steam supply systems. For example, by using components such as dynamic pipes and deflection headers in the marine condition component library to reconstruct one-dimensional multi-channel coolant channels, pressurizer dynamic air cushion volume, and main coolant pump variable gravity boundary model, a full system analysis of the autonomous anti-sway characteristics of the primary loop natural circulation can be achieved. The applicable reactor types can also be extended to micro modular floating reactors, marine high-temperature gas-cooled reactors, marine condition liquid metal-cooled fast reactors represented by lead-bismuth fast reactors and sodium fast reactors, and low-pressure marine floating molten salt reactors, etc. Regarding fluid media, by replacing the basic module of the fluid state equation of the component, the marine condition component library is also applicable to liquid lead-bismuth eutectic (LBE), liquid sodium, supercritical carbon dioxide, helium, and various organic working fluids used in organic Rankine Cycle (ORC) waste heat recovery systems. Its underlying three-dimensional bulk force vector projection logic and windward enthalpy smoothing mechanism do not require substantial modification and can directly exert the technical effect of suppressing numerical integral divergence. In terms of deployment, the marine condition component library can follow the standard Modelica 3.4 and higher language specifications. It can be called and compiled as a native fluid library in commercial modeling software such as Dynamic Modeling Laboratory (Dymola), and can also be ported and imported to any other object-oriented multiphysics modeling platform that supports the Modilika language standard, such as the open-source modeling platform OpenModelica, the commercial platforms Wolfram SystemModeler, MapleSim, SimulationX, and domestic all-digital simulation software. In terms of functional encapsulation, each core main equipment component and complete loop model in the marine condition component library can be encapsulated into a standard functional model unit (FMU) with one click using the Functional Mock-up Interface (FMI) version 1.0, 2.0, or 3.0. It can be exported as a model exchange format with a unified numerical integration bus provided by an external master solver, or it can be exported as a co-simulation format to include an embedded adaptive step-size implicit integrator. This application does not limit this.

[0085] The method provided in this embodiment establishes a simulation model by determining target components from a library of ocean condition components encapsulating fluid equations in a non-inertial frame, and configuring position vectors and unit direction vectors for each target component. This allows the simulation model to adapt to different system spatial layouts in a modular and reusable manner, without repeatedly modifying the underlying code for different layouts. During the simultaneous solution process, the apparent gravity pressure drop source term is obtained by projecting the three-dimensional body forces determined based on the six-degree-of-freedom motion boundary conditions, position vectors, and flow velocities onto the one-dimensional axis direction via unit direction vectors. This enables the one-dimensional fluid equations to be... Accurately sensing the differentiated mechanical effects of ship motion in three-dimensional space on target components with different spatial positions and axial orientations improves the simulation accuracy of transient thermo-hydraulic parameters under marine conditions. Furthermore, by smoothing the specific enthalpy corresponding to forward flow and reverse flow using preset flow tolerances to obtain the windward specific enthalpy, the Jacobian matrix singularity problem caused by the derivative step jump when the flow frequently crosses zero and reverses is eliminated, ensuring the numerical stability of the simultaneous solution process under extreme sea state oscillations, thereby improving the accuracy and stability of transient simulation of thermo-hydraulic systems under marine conditions.

[0086] In some embodiments, the apparent gravitational pressure drop source term in the momentum conservation equation for each target component is calculated based on the following steps: Based on the six-degree-of-freedom motion boundary conditions, determine the translational acceleration, angular velocity, and angular acceleration of the ship; The Euler acceleration is obtained by performing a cross product operation between the angular acceleration and the position vector of the target component. The centrifugal acceleration is obtained by performing a cross product operation between the angular velocity and the position vector of the target component, and then performing a cross product operation between the result of the cross product operation and the angular velocity. The angular velocity is cross-multiplied with the flow velocity of the fluid inside the target component, and the Coriolis acceleration is obtained based on the cross-multiplication result. The total acceleration is obtained by summing the translational acceleration, the Euler acceleration, the centrifugal acceleration, and the Coriolis acceleration. The three-dimensional body force is determined based on the difference between the gravitational acceleration and the total acceleration. The three-dimensional mass force is projected onto the one-dimensional axis direction of the target component through the unit vector of the target component to obtain the apparent gravitational pressure drop source term in the momentum conservation equation of the target component.

[0087] Translational acceleration refers to the three-dimensional acceleration vector generated by the ship's translational motions such as undulation, pitching, and swaying; angular velocity and angular acceleration refer to the three-dimensional angular velocity vector and three-dimensional angular acceleration vector generated by the ship's rotational motions such as rolling, pitching, and yaw, respectively. Translational acceleration, angular velocity, and angular acceleration can be directly read from the motion time history information contained in the six-degree-of-freedom motion boundary conditions, or they can be obtained by performing first-order and second-order time derivatives on the attitude angle time history. This application does not limit this.

[0088] Optionally, according to such Figure 2 The force analysis shown shows that the apparent gravitational pressure drop source term in the non-inertial reference frame of any target component can be expanded as follows: ; in, For the apparent gravitational pressure drop source term, The density of the fluid within the target component. The length of the target component, Let the direction of the target component be the unit vector. It is the acceleration due to gravity; This refers to the ship's translational acceleration. For the ship's angular acceleration, The position vector of the target component relative to the motion reference point. For Euler acceleration; Let be the angular velocity of the ship. Centrifugal acceleration; The fluid velocity within the target component. For Coriolis acceleration; This is a three-dimensional body force, and the direction of this three-dimensional body force is a unit vector. The dot product projection yields the apparent gravitational pressure drop source term in the momentum conservation equation of the target component.

[0089] It is understandable that Euler acceleration characterizes the tangential acceleration effect of changes in the ship's rotational angular velocity on the fluid, and its magnitude is proportional to the distance from the target component to the motion reference point; the direction of centrifugal acceleration always deviates from the center of rotation, and its magnitude is related to the square of the angular velocity; Coriolis acceleration characterizes the coupling effect between the relative motion of the fluid and the ship's rotation, and it changes in real time with the fluid velocity. This embodiment synthesizes translational acceleration, Euler acceleration, centrifugal acceleration, and Coriolis acceleration into a total acceleration, and determines the three-dimensional body force by the difference between gravitational acceleration and the total acceleration. This achieves the synthesis of the complete three-dimensional additional inertial force vector and the apparent gravity pressure drop of the gravity projection, which includes spatial translational acceleration, Euler force, centrifugal force, and Coriolis force. This avoids the physical incompleteness caused by only explicitly introducing some additional inertial force source terms such as translational and swaying Euler forces in related technologies. It enables the one-dimensional dynamic pipeline to sensitively and accurately perceive the three-dimensional centrifugal swaying and Coriolis deflection effect generated by the fluid as the hull sways and undulates, so as to accurately assess the nonlinear oscillation mechanism of the full-loop flow under marine conditions.

[0090] In some embodiments, during the simultaneous solution process, the frictional pressure drop term in the momentum conservation equation for each target component is calculated based on the following steps: The reference frictional pressure drop is determined based on the friction coefficient along the path, the length, diameter, flow cross-sectional area of ​​the target component, the density of the fluid inside the target component, and the transient mass flow vector. The ship's tilt angle is determined based on the six-degree-of-freedom motion boundary conditions. The dynamic correction factor is determined based on the ship's inclination angle; The reference frictional pressure drop is corrected according to the dynamic correction coefficient to obtain the frictional pressure drop term in the momentum conservation equation of the target component; the dynamic correction coefficient is used to compensate for the calculation deviation of the wall shear force when the ship is in a tilted state.

[0091] Optionally, the formula for calculating the frictional pressure drop term in the momentum conservation equation for any target component can be: ; in, This is the frictional pressure drop term; This is a dynamic correction factor; The friction coefficient along the friction path can be used, such as the Darcy-Weisbach friction coefficient. The length of the target component; The diameter of the target component, The density of the fluid within the target component. The cross-sectional area of ​​the target component; The reference frictional pressure drop. This is the transient mass flow vector; It is the product of the transient mass flow vector and the absolute value of the mass flow vector. Its core purpose is to automatically handle changes in flow direction and ensure the correctness of the direction of frictional pressure drop.

[0092] The ship's heel angle can be determined based on the attitude angle time history in the six-degree-of-freedom motion boundary conditions, such as the roll angle, pitch angle, or a combination of both. The dynamic correction coefficient is a correction coefficient associated with the ship's heel angle, used to compensate for the deviation in the calculation of one-dimensional wall shear force caused by three-dimensional slippage and secondary flow phenomena of the fluid within the pipe cross-section when the ship is in an inclined state. It should be noted that the specific mathematical expression of the dynamic correction coefficient is not limited. It can adopt a semi-empirical formula fitted based on a specific marine thermal-hydraulic experimental platform, such as a single-phase or two-phase boiling flow experiment in a swinging pipe; it can also adopt a higher-dimensional nonlinear projection formula derived from analytical geometry; or it can use an artificial neural network substitution model for equivalent replacement, as long as it can characterize the influence of spatial attitude on wall shear. This application does not limit this aspect.

[0093] This embodiment introduces a dynamic correction coefficient that varies with the ship's inclination angle on the basis of the reference frictional pressure drop, which automatically compensates for the calculation deviation of the one-dimensional wall shear force caused by the three-dimensional slip and secondary flow phenomena of the fluid under large ship inclination angles. This makes the frictional pressure drop term and the apparent gravity pressure drop source term match each other in terms of physical mechanism, and further improves the fidelity of solving the momentum conservation equation under marine conditions.

[0094] In some embodiments, the target component includes a main pipe component; the component parameters of the main pipe component also include port position vectors of each branch port relative to the central node of the main pipe component; In the process of solving the simultaneous equations, the momentum conservation equations of the target components connected to each of the branch ports are solved simultaneously with the back pressure of the branch ports as the pressure boundary. The back pressure of each branch port is calculated based on the following steps: Based on the six-degree-of-freedom motion boundary conditions, determine the real-time apparent gravitational acceleration; The real-time apparent gravitational acceleration is multiplied by the position vector of each port, and the deflection head of each branch port is determined based on the result of the dot product and the density of the fluid in the main pipe assembly. The back pressure of each branch port is determined based on the pressure of the central node and the deflection head of each branch port.

[0095] The main pipe assembly refers to the component that serves as a hub connecting multiple branches. The core calculation of the main pipe assembly relies on the state dependence of the fluid; that is, the fluid density is calculated using transient pressure and transient specific enthalpy. In specific implementation, the transient pressure within the effective volume of the main pipe assembly... Compared with transient enthalpy The mass-energy coupled partial differential equations can be solved by directly expanding the total differential terms and solving them simultaneously: ; ; In the formula, The effective volume of the main pipe assembly. and These are the partial derivatives of fluid density with respect to transient pressure and fluid density with respect to transient specific enthalpy, respectively. and The first of each of the mother tube assembly Transient flow rate and specific enthalpy on the windward side of the branch; This refers to the number of branches in the main pipe assembly.

[0096] Here, the port position vector refers to the three-dimensional position vector of each branch port of the main pipe assembly relative to the center node of the main pipe assembly. Each port position vector can be encapsulated within the main pipe assembly in the form of a local three-dimensional coordinate array. To reflect the dynamic flow deviation caused by swaying, the actual back pressure at each branch port can be precisely corrected as follows: ; In the formula, For the first The actual back pressure at the port of the branch, The pressure at the central node of the mother pipe assembly. This refers to the density of the fluid within the target component, which in this case is the density of the fluid within the main pipe component. This is the real-time apparent gravitational acceleration vector determined based on the six-degree-of-freedom motion boundary conditions. For the first The port position vector of a branch relative to the central node of the main pipe.

[0097] Understandably, regardless of how the main pipe geometry is arranged in the global coordinate system, the simulation model can calculate the projection of the apparent gravity onto the geometric vectors of each branch port based on the real-time input of the ship's six degrees of freedom attitude angles, thereby accurately reproducing the flow deviation phenomenon caused by static pressure distortion in the lower-positioned branch when the ship tilts at a large angle.

[0098] This embodiment achieves high-fidelity reproduction of large-angle tilted static pressure distortion by using a local three-dimensional coordinate array at the port and dynamic correction of the bias head. It restores the amplification effect of the spatial geometric height difference of the system under the real asymmetric three-dimensional compact arrangement on the alternating solid force field, so that the target components connected to each branch port can be solved simultaneously with the real dynamic back pressure as the pressure boundary, thus improving the simulation accuracy of flow redistribution at multi-branch hubs.

[0099] In some embodiments, the target component includes a steam-water separator component; In the process of solving the simultaneous equations, the mass flow distribution between the vapor phase outlet and the liquid phase outlet in the mass conservation equation of the steam-water separator assembly, and the outlet specific enthalpy of the vapor phase outlet in the energy conservation equation of the steam-water separator assembly, are all determined based on the transient water carrying capacity of the steam-water separator assembly. The transient water carrying capacity is calculated based on the following steps: Based on the six-degree-of-freedom motion boundary conditions, determine the ship's tilt angle and the gravity deviation of the vertical apparent gravity from the reference gravity. The tilt correction amount is determined based on the tilt sensitivity coefficient and the sine value of the tilt angle; The gravity fluctuation correction amount is determined based on the gravity fluctuation sensitivity coefficient and the ratio between the gravity deviation and the reference gravity. The rated water carrying capacity of the steam-water separator assembly is corrected based on the tilt correction amount and the gravity fluctuation correction amount to obtain the transient water carrying capacity.

[0100] The water carrying capacity refers to the mass fraction of liquid droplets entrained in the steam discharged from the steam-water separator. Under adverse sea conditions, changes in the ship's roll or pitch angles and the magnitude of local vertical apparent gravity can lead to a decrease in separation efficiency. Therefore, this embodiment models the transient water carrying capacity as a time-varying function, constructing a steam-water separator component with a dynamic water carrying mechanism. ; In the formula, For the steam-water separator assembly in Transient water carrying capacity at a given time point This refers to the rated water carrying capacity under rated stable sea conditions. The tilt sensitivity coefficient, For ships in The tilt angle at a given time point can be either transient roll or pitch angle. This is the tilt correction amount; The sensitivity coefficient to gravitational fluctuations. for The vertical apparent gravity deviation from the baseline gravity at a given time point is used to characterize the degree of weightlessness or overweight. As the reference gravity, This is the correction amount for gravity fluctuations.

[0101] Understandably, this time-varying function captures the two-phase dynamic failure mechanism within the steam-water separator: when the ship tilts at a large angle and the inclination angle increases, the effective flow cross-section of the corrugated plate separator decreases and the droplet collision angle deviates, leading to a deterioration in separation efficiency; while in the weightlessness stage caused by undulating motion, i.e., when the gravity deviation is less than zero, the droplet settling velocity drops nonlinearly, intensifying water carrying. During the simultaneous solution process, the mass flow rate distribution between the vapor phase outlet and the liquid phase outlet in the mass conservation equation of the steam-water separator assembly, as well as the outlet specific enthalpy of the vapor phase outlet in the energy conservation equation, can be determined based on the transient water carrying rate. For example, the mass flow rate of the droplets entrained at the vapor phase outlet increases with the increase of the transient water carrying rate, and the outlet specific enthalpy of the vapor phase outlet correspondingly decreases with the increase of the proportion of saturated droplets carried.

[0102] This embodiment uses a dual-drive correction of the rated water carrying capacity through tilt correction and gravity fluctuation correction to map the macroscopic ship kinematic boundary into the dynamic deterioration of the microscopic separation efficiency between the gas and liquid phases and the abnormal water carrying phenomenon. This effectively couples the three-dimensional sea state depth into the thermodynamic separation boundary between the gas and liquid phases, making up for the shortcomings of conventional fluid components that cannot take into account the microscopic separation deterioration caused by three-dimensional tilt.

[0103] In some embodiments, the target component includes a steam generator component, and the fluid equations of the steam generator component further include a pressure conservation equation and a heat transfer coefficient equation. In the process of solving the simultaneous equations, the transient pressure change rate in the pressure conservation equation and the dynamic total heat transfer coefficient in the heat transfer coefficient equation are calculated based on the following steps: The first mass change term is determined based on the liquid phase volume of the steam generator assembly, the partial derivative of the saturated liquid density with respect to the saturated liquid enthalpy, and the rate of change of the saturated liquid enthalpy. The second mass change term is determined based on the vapor phase volume of the steam generator assembly, the partial derivative of the saturated vapor density with respect to the saturated vapor enthalpy, and the rate of change of the saturated vapor enthalpy. The transient pressure change rate is calculated based on the inlet mass flow rate, outlet mass flow rate, first mass change term, second mass change term, the product of the liquid phase volume and the partial derivative of the saturated liquid density with respect to pressure, and the product of the vapor phase volume and the partial derivative of the saturated vapor density with respect to pressure of the steam generator assembly. The ship's tilt angle is determined based on the six-degree-of-freedom motion boundary conditions. The heat transfer area attenuation function value is determined based on the ship's inclination angle and the liquid level in the steam generator assembly. The dynamic overall heat transfer coefficient is determined based on the rated overall heat transfer coefficient, the heat transfer area decay function value, and the ratio between the real-time mass flow rate of the primary side and the rated mass flow rate of the primary side.

[0104] Alternatively, assuming the vapor-liquid two-phase structure of the steam generator assembly is in thermodynamic equilibrium, this can be based on a constant volume constraint. The rigid differential equation of pressure is derived as the pressure conservation equation: ; In the formula, The transient pressure change rate, and These are the inlet and outlet mass flow rates of the steam generator assembly, respectively. and These are the liquid phase volume and the vapor phase volume, respectively. , , , These are, respectively, the density of saturated liquid, the density of saturated vapor, the specific enthalpy of saturated liquid, and the specific enthalpy of saturated vapor; This is the first mass change term. The second mass change term; in the denominator and These are the products of the partial derivatives of the liquid phase volume and the saturated liquid density with respect to pressure, and the products of the vapor phase volume and the saturated vapor density with respect to pressure, respectively. The core idea of ​​this pressure conservation equation is to treat the two-phase region as a thermodynamic equilibrium system with a dynamic boundary, and the denominator terms as a whole characterize the overall system pressure inertia of the two-phase fluid during the phase transition process.

[0105] Furthermore, the dynamic overall heat transfer coefficient in the heat transfer coefficient equation can be expressed as: ; In the formula, The dynamic overall heat transfer coefficient, The rated overall heat transfer coefficient, and These are the real-time mass flow rate and the rated mass flow rate on the primary side, respectively. For the ship's inclination angle, The liquid level within the steam generator assembly. This is the heat transfer area attenuation function constrained by both tilt angle and liquid level. This function can be constructed based on an analytical geometric model to calculate in real-time the nonlinear sharp decrease in boiling heat transfer area when a heat transfer tube bundle, such as a U-shaped tube bundle, is exposed in the vapor phase due to liquid tilt. It should be noted that the specific mathematical expression of the heat transfer area attenuation function can be equivalently replaced by a semi-empirical formula fitted from experiments, a nonlinear projection formula derived from analytical geometry, or an artificial neural network substitution model, as long as it can characterize the influence of spatial orientation on the two-phase interface and the heat transfer area. Furthermore, under other high-precision or strong non-equilibrium transient operating conditions, the two-phase thermodynamic equilibrium analytical model used in the steam generator assembly can be replaced or reconstructed into a more complex two-phase non-equilibrium transport model, such as the rigorous Two-Fluid Six-Equation Model. This model treats the vapor phase and liquid phase as independent continuous media, establishes two sets of mutually coupled partial differential conservation equations for mass, momentum, and energy, and embeds interphase mass exchange terms, interphase momentum friction resistance terms, and interphase heat transfer terms modulated by sea state disturbances at the phase interface. This application does not limit this aspect.

[0106] This embodiment combines the state-dependent pressure conservation equation with the dynamic total heat transfer coefficient constrained by both tilt angle and liquid level, enabling the steam generator assembly to have the physical perception capability of macroscopic ocean attitude changes. It explicitly demonstrates the destruction mechanism of the heat transfer boundary layer by ocean conditions, realizes the continuous transition and accurate evaluation of the phase change heat transfer process under sea state disturbance, and improves the computational fidelity of complex phase change processes.

[0107] In some embodiments, the target component includes a condenser assembly; the fluid equation of the condenser assembly further includes a level differential equation. In the process of solving the simultaneous equations, the rate of change of hot well liquid level in the liquid level differential equation is calculated based on the following steps: The liquid phase volume expansion correction is determined based on the transient pressure change rate, liquid phase volume, and partial derivative of liquid phase density with respect to pressure within the condenser assembly. The net change in the mass of the hot well is determined based on the difference between the condensation and outflow of the condenser assembly and the liquid phase volume expansion correction. The rate of change of hot well liquid level is determined based on the net change in the mass of the hot well, the liquid phase density of the fluid in the condenser assembly, and the cross-sectional area of ​​the hot well.

[0108] Optionally, to capture the transient effects of pressure fluctuations on the hot well water level, the condenser assembly abandons the conventional incompressibility assumption and constructs a rigorous mass-volume coupled partial differential equation containing fluid state partial derivatives as the liquid level differential equation: ; In the formula, This represents the rate of change of the hot well liquid level. This refers to the condensation rate of the condenser assembly. This refers to the outflow rate of the condenser assembly. This represents the real-time volume occupied by the liquid phase within the condenser assembly. This is the partial derivative of the saturated liquid density with respect to pressure, also known as the partial derivative of the liquid phase density with respect to pressure. The transient pressure change rate, This is the correction amount for liquid phase volume expansion; This is the net change in the mass of the hot well; This is the saturated liquid density, which is also the liquid phase density of the fluid within the condenser assembly. This represents the cross-sectional area of ​​the thermal well.

[0109] It is understandable that the dynamic evolution of the hot well liquid level is thus deeply coupled with the liquid phase volume expansion effect caused by the drastic pressure change; and the condenser assembly can also achieve a continuous transition of physical state by relying on the mechanism of the smooth decrease of the dynamic effective heat exchange area with the ship's tilt angle.

[0110] This embodiment incorporates the liquid phase volume expansion correction into the calculation of the net change in hot well mass, freeing the solution of the hot well liquid level change rate from the limitation of the incompressibility assumption. This purely physical-driven solution framework fundamentally ensures the continuity of the Jacobian matrix of the implicit solver when dealing with high-frequency marine transients, improving the accuracy and solution stability of the condenser hot well liquid level transient prediction.

[0111] In some embodiments, the target component includes a pump assembly; the fluid equations for the pump assembly further include an effective head equation. In the process of solving the simultaneous equations, the effective pressure head in the effective pressure head equation is calculated based on the following steps: The steady-state head of the pump assembly is determined based on the characteristic curve fitting coefficient, volumetric flow rate, and transient rotational angular velocity of the pump assembly. Based on the six-degree-of-freedom motion boundary conditions, determine the apparent acceleration of the ship; The dynamic head compensation term is determined based on the directional unit vector of the pump assembly, the apparent acceleration, and the density of the fluid within the pump assembly. The effective pressure head is determined based on the steady-state pressure head and the dynamic pressure head compensation term.

[0112] Optionally, the effective head equation of the pump assembly combines the steady-state polynomial with the high-frequency dynamic head, and the actual transient effective head of the pump assembly can be expressed as: ; In the formula, The effective head output by the pump assembly; , , The coefficients for fitting the characteristic curve of the pump assembly are the quadratic polynomial fitting coefficients for the pump characteristic curve. This refers to the volumetric flow rate of the pump assembly. This refers to the transient rotational angular velocity. This is the standard gravitational acceleration; The direction unit vector of the target component; The apparent acceleration, which incorporates the effects of six degrees of freedom motion, is determined in real time based on the boundary conditions of the six-degree-of-freedom motion. This refers to the density of the fluid within the target component, which in this case is the density of the fluid within the pump component. The density is the saturated liquid density.

[0113] Understandably, the dynamic head compensation term is a high-frequency dynamic compensation term. Physically, it represents the local transient additional pressure rise caused by the sudden change in absolute acceleration of the fluid in the pump body when it is violently rising and falling and swaying with the ship. It can better simulate the dynamic water pressure drop at the pump inlet caused by waves.

[0114] This embodiment superimposes a dynamic head compensation term containing the apparent acceleration vector onto the steady-state polynomial characteristic curve, enabling the pump assembly to realistically reproduce the transient distortion of local dynamic water pressure drop at the pump inlet caused by wave fluctuations. This overcomes the shortcomings of conventional pump models, which can only characterize steady-state characteristics and cannot perceive the alternating inertial environment of the ocean.

[0115] In some embodiments, the target component includes a steam turbine assembly; the fluid equations of the steam turbine assembly also include work equations; In the process of solving the simultaneous equations, the work term in the work equation is calculated based on the following steps: Based on the six-degree-of-freedom motion boundary conditions, determine the transient yaw rate of the ship; The rotor spin angular velocity of the turbine assembly is cross-multiplied with the transient oscillation angular velocity, and the transient gyro torque is determined based on the cross-multiplication result and the rotor moment of inertia of the turbine assembly. Based on the transient gyro torque, determine the additional mechanical frictional power consumption of the bearing system acting on the turbine assembly; The theoretical output power of the turbine assembly is determined based on the inlet steam mass flow rate, isentropic enthalpy drop, and isentropic efficiency of the turbine assembly. The work item is determined based on the difference between the theoretical output power and the additional mechanical friction power consumption.

[0116] Optionally, in this embodiment, the turbine assembly incorporates a rotor rigid body dynamics model, and the transient gyroscopic torque generated by the interaction between the ship's rolling motion and the high-speed rotor is calculated through cross-product operations: ; In the formula, For transient gyroscope torque, The moment of inertia of the rotor can be characterized using the rotor's moment of inertia tensor. ω represents the rotor spin angular velocity, which can be the high-speed rotor spin angular velocity vector; The transient roll rate of the ship is determined based on the six-degree-of-freedom motion boundary conditions.

[0117] This transient gyroscopic torque acts on the bearing system to generate additional mechanical frictional power consumption; correspondingly, the actual net output power of the turbine assembly, as the work term, can be corrected as follows: ; In the formula, This refers to the work done, i.e., the actual net output power of the turbine assembly; This refers to the inlet steam mass flow rate of the steam turbine components. The isentropic enthalpy drop at the steam inlet and outlet. For isentropic efficiency, This is the theoretical output power of the steam turbine assembly; This refers to the additional mechanical frictional power consumption acting on the bearing system caused by transient gyro torque and variable gravitational field. The apparent acceleration, which incorporates the effects of six degrees of freedom motion, is determined in real time based on the boundary conditions of the six-degree-of-freedom motion.

[0118] Understandably, through vector cross-product calculation, the turbine components capture the gyroscopic effect that the high-speed rotor inevitably generates in a non-inertial rotating system to resist precession displacement, and convert this strong alternating stress into bearing friction work loss in real time, which is directly deducted from the turbine's thermodynamic internal work.

[0119] This embodiment integrates rotor rigid body dynamics into the work equation of the turbine assembly, quantitatively elucidating the intrinsic physical mechanism of the dynamic loss of the turbine's effective work power caused by complex rigid body swaying at the macroscopic level. It realizes a deep interdisciplinary coupling between thermo-fluid dynamics and rigid body dynamics, making up for the insufficiency of conventional fluid assemblies in quantifying the additional frictional power consumption of rigid body dynamics.

[0120] To verify the effectiveness of the thermal-hydraulic system simulation method based on marine condition component library provided in this application, the following explanation is combined with multiphysics benchmark experiments and full-system-level engineering application examples.

[0121] Specifically, during the verification process, to ensure the accuracy of the computational fluid dynamics characteristics of the marine condition component library in a non-inertial frame, dual benchmark verifications of static tilting and dynamic swaying were first performed. Furthermore, a transient simulation model of the entire secondary loop system of a marine nuclear power plant was built to simulate and analyze the transient response characteristics under typical single-degree-of-freedom marine conditions and multi-degree-of-freedom extreme sea states.

[0122] In the static tilt verification process, to verify the ability of components in the Ocean Condition Component Library to perceive spatial hydrostatic head distortion based on position vectors, i.e., to examine the solution accuracy of the three-dimensional projection mechanism of the apparent gravity pressure drop source term under static tilt boundaries, components in the Ocean Condition Component Library were used to reproduce the micro-single-phase natural circulation bench experiment. For the natural circulation attenuation and flow stability problems of nuclear power systems under tilted and static ship conditions, such as grounding or extreme static roll, a verification model was constructed in the Dynamic Modeling Laboratory (Dymola) referencing classic single-phase natural circulation micro-loop experiments.

[0123] Figure 4 This is a schematic diagram of the verification model for the static tilting experiment of a single-phase natural circulation micro-loop provided by the present invention, wherein T1, T2, T3, and T4 are all temperature measurement points. Figure 4 As shown, the heating and cooling sections in the verification model are arranged in horizontal pipes at the bottom and top, respectively. In order to accurately replicate the stepped heating boundary from 2.5 watts to 25 watts in the experiment, the bottom horizontal heating pipe section of the verification model uses 5 constant heat flux density sources for distributed heat loading. The rising and falling sections use pipe components developed independently from the marine condition component library, with an elevation difference of 0.156 meters. On the cooling side, a coaxial sleeve heat exchanger component developed independently from the marine condition component library is introduced, with an effective length of 0.183 meters. The shell side uses a 50% volume fraction ethylene glycol aqueous solution as a cold trap, and the tube side is mainly circulating deionized water.

[0124] The initial system heating power was set to 2.5 watts. The experimental platform was statically tilted within the range of 0 to 20 degrees to compare the steady-state temperature difference evolution of the hot and cold pipes at different tilt angles.

[0125] Figure 5 This is a schematic diagram of the temperature difference between the hot and cold sections as a function of heating power under steady-state tilting conditions provided by the present invention. Figure 6 This is a schematic diagram of the prediction error distribution under steady-state tilting conditions provided by the present invention.

[0126] like Figure 5 and Figure 6As shown, under the same heating power, as the static tilt angle increases from 0 degrees to 20 degrees, the steady-state temperature difference between the hot and cold sections gradually widens. The physical mechanism is that the increase in tilt angle causes the effective driving head provided by the elevation difference between the rising and falling sections to decrease according to the law of gravity projection, and the natural circulation flow rate decreases accordingly, resulting in a larger temperature rise of the fluid under the same heating amount. Since the momentum conservation equations of each pipe component in the verification model accurately reconstruct the local gravity projection vector, that is, based on the position vector and the unit direction vector, the three-dimensional body force after tilting is strictly projected onto the one-dimensional axis direction, the simulation curve closely matches the experimental measurement curve at all tilt angles and all power points, completely tracking the multi-dimensional thermal inertial evolution law between the decrease in driving head, the decrease in flow rate, and the expansion of temperature difference. The prediction error of the peak temperature difference is strictly controlled within 5% across the entire tilt angle range. This result confirms that the component encapsulating the fluid equations in a non-inertial frame has extremely high fidelity in its response to the one-dimensional flow field caused by three-dimensional deflection.

[0127] Figure 7 This is a schematic diagram of the layout of the single-phase forced cycle test bench under dynamic swing conditions provided by the present invention.

[0128] like Figure 7 As shown, during the dynamic rocking verification process, to verify the high-frequency numerical robustness of the marine condition component library under extreme alternating inertial force impact, and the anti-divergence capability of the windward side specific enthalpy smoothing mechanism, sinusoidal pitch motion boundaries with periods of 7.5 seconds and 10 seconds and a maximum swing angle of 20 degrees can be injected into a dynamic closed forced circulation channel model containing a vertical riser up to 2.4 meters high. When the simulation is advanced under a variable step size implicit differential algebraic system solver, the pitch motion induces violent alternating additional momentum source terms in the 2.4-meter-high vertical riser and fallr; according to the vector projection equation of the component's bottom layer, due to the superposition of the pitch angle and short period, the fluid in the pipe is subjected to strong angular acceleration, i.e., Euler inertial force and tangential gravity components, high-frequency disturbances.

[0129] Figure 8 This is a schematic diagram comparing the transient response of forced circulation mass flow rate under a 15-degree swing angle condition with a 7.5-second cycle, as provided by the present invention. Figure 9 This is a schematic diagram comparing the transient response of forced cyclic mass flow rate under a 10-second cycle at a 15-degree swing angle, as provided by the present invention. Figure 10 This is a schematic diagram comparing the transient response of forced circulation mass flow rate under different amplitudes in a 10-second periodic tilting condition, as provided by the present invention. Figure 10 (a) is a comparative schematic diagram of the transient response of mass flow rate under a 10-second cycle and a 10-degree tilt condition; Figure 10 (b) is a comparative schematic diagram of the transient response of mass flow rate under a 10-second period and a 20-degree pitch condition. The solid lines in each sub-figure are the baseline solutions, and the dashed lines are the simulation solutions of the verification model based on the marine condition component library.

[0130] like Figure 8 , Figure 9 and Figure 10 As shown, the simulation model established based on the marine condition component library accurately tracks the alternating inertial force field induced by tangential Euler angular acceleration. The flow evolution curve exhibits sinusoidal pulsation characteristics with the same frequency as the oscillating motion. More importantly, under the extremely high precision requirements of the variable step-size integrator propulsion tolerance, when the fluid experiences flow troughs or even local minimum flow velocities, the entire calculation process is smooth and stable, without any sudden reduction in step size, divergence, or dead loops in the trial step. This overcomes the numerical rigidity defects of standard fluid components when dealing with alternating inertial disturbances and verifies the anti-divergence capability of the mechanism of smoothing the windward enthalpy by using preset flow tolerance under the condition of frequent zero-crossing and reversal of flow.

[0131] Furthermore, to fully demonstrate the engineering application value of the method provided in the embodiments of this application, a transient simulation model of the entire secondary loop system of a 175 MW marine nuclear power plant was built based on various marine-specific components in the marine condition component library, including directional flow deflection main pipe components, dynamic water-carrying steam-water separator components, and steam turbine components incorporating gyroscopic effects.

[0132] Figure 11 This is a schematic diagram of the secondary loop system of a marine nuclear power plant provided by the present invention, as shown below. Figure 11 As shown, the three-dimensional spatial topology of the secondary loop system in the ship's three-dimensional coordinate system includes a steam generator positioned slightly forward and high on the centerline, a steam header serving as a high-pressure steam distribution hub, high-pressure and low-pressure cylinders arranged along the ship's length, a deaerator located at the highest point of the system, a steam-water separator positioned off the centerline, a condenser located deep within the hull, and a condensate pump located at the lowest point of the system, along with a feedwater pump symmetrically arranged along the ship's centerline. The position vectors and positional characteristics of each key component's spatial topology configuration are shown in Table 1.

[0133] Table 1 Spatial Topology Information of the Two-Loop System

[0134] The simulation conditions were specifically set as follows: under stable sea conditions, i.e., all six degrees of freedom motion boundary conditions are zero, the initial steady-state equilibrium verification was performed under 100% full power (FP) conditions.

[0135] As shown in Table 2, the verification results show that the design values ​​of key thermodynamic parameters of the secondary loop system, such as the feedwater flow rate of 83.5 kg / s and the high-pressure cylinder inlet pressure of 5.8 MPa, are in high agreement with the simulation values. The error of most parameters is controlled within 1%, and the maximum error is only 2.91%, which effectively proves the baseline thermodynamic accuracy of the simulation model of the secondary loop system.

[0136] Table 2. Distribution of Steady-State Values ​​of Key FP Parameters

[0137] Subsequently, the transient response characteristics of typical single-degree-of-freedom ocean conditions and multi-degree-of-freedom extreme sea states were analyzed using the simulation model of the two-loop system.

[0138] For typical marine conditions with a single degree of freedom, undulating motion is mainly manifested as translational acceleration impact along the vertical direction of the hull, which can simulate the alternating environment of overweight and weightlessness caused by severe waves at the simulation input end.

[0139] Figure 12 This is one of the schematic diagrams of the transient evolution curve of the principal mass flow rate of a two-loop system under fluctuating single-degree-of-freedom conditions provided by the present invention. Figure 13 This is the second schematic diagram of the transient evolution curve of the main mass flow rate of a two-loop system under fluctuating single-degree-of-freedom conditions provided by the present invention.

[0140] like Figure 12 and Figure 13 As shown, the flow response curve exhibits an extremely regular, symmetrical single sinusoidal waveform. The fluctuation frequency is consistent with the injected fluctuation excitation frequency, and throughout the entire evolution cycle of the peaks and troughs, the average flow baseline of the system remains stably maintained near the rated level, without any macroscopic system energy drop. The physical mechanism is as follows: a vertical riser exists between the deaerator located at the highest point of the secondary loop system and the pump body located at the lowest point. When the fluctuation motion causes a surge or decay in apparent gravity, the hydrostatic head within this riser generates a symmetrical alternating driving force. Simultaneously, since the fluctuation process is purely translational with no rotational component involved (i.e., the angular velocity is zero), the centrifugal acceleration and Coriolis acceleration components in the momentum conservation equations of each target component are not excited. The fluid is not affected by the unidirectional weakening effect of the centrifugal dissipation pressure drop, thus the flow increase during the overweight phase and the flow decrease during the weightlessness phase are strictly symmetrical. This result demonstrates that the simulation model of the secondary loop system correctly calculates the symmetrical alternating pressure drop formed by the projection of the translational acceleration onto the vertical riser axis via a unit vector.

[0141] For the transient response characteristics of single-degree-of-freedom pitching, under the six-degree-of-freedom motion boundary conditions, only a sinusoidal pitching angle motion excitation around the hull transverse axis is injected. At this time, the momentum conservation equation of the target component not only contains the tangential Euler acceleration component generated by the cross product of angular acceleration and position vector, but also the normal centrifugal acceleration component related to the square of angular velocity.

[0142] Figure 14 This is a schematic diagram of the transient evolution curve of the principal mass flow rate of a two-loop system under a single degree of freedom of pitching, provided by the present invention. Figure 14 Part (a) shows the complete waveform of the main steam flow over several pitch cycles. Figure 14Part (b) shows a locally magnified waveform of the flow pulsation and the drift trend of the flow baseline.

[0143] like Figure 14 The simulation results show that the main steam flow exhibits a unique bimodal waveform during each pitching cycle, and as the simulation progresses, the overall mass flow baseline of the system drifts significantly downward relative to the rated value. The physical mechanism is as follows: As shown in Table 1, the spatial coordinates of the front steam generator and the rear turbine and low-pressure cylinder span a large horizontal arm along the ship's length. The pitching and tilting motions transform this horizontal arm into an alternating vertical elevation difference, applying additional hydrostatic head to the pipeline network according to a sinusoidal law, thus forming the driving source of the bimodal waveform. Unlike the fluctuating condition, the direction of the centrifugal acceleration component calculated in the momentum conservation equations of each component always deviates from the center of rotation, constituting a unidirectional background dissipation independent of the pitching direction. Under the continuous pressure of this centrifugal dissipation, the flow baseline undergoes an irreversible downward drift. These results demonstrate that the simulation model fully reproduces the superposition characteristics of the alternating driving effect of Euler acceleration and the unidirectional dissipation effect of centrifugal acceleration in the same waveform.

[0144] For the single-degree-of-freedom roll response characteristics of the turbine, only a sinusoidal roll angle motion excitation around the longitudinal axis of the hull is injected under the six-degree-of-freedom motion boundary conditions. Roll is the most common and largest motion mode encountered by marine nuclear power systems. Under this excitation, the simulation model not only solves the flow deviation response of the pipeline fluid, but also quantifies the asymmetric energy loss of the core power-generating equipment through the rotor rigid body dynamics model built into the turbine components.

[0145] Figure 15 This is a schematic diagram of the transient evolution curve of the principal mass flow rate of a two-loop system under a single degree of freedom of roll, as provided by the present invention. Figure 15 The vertical axis of section (a) shows the main pipeline mass flow rate, illustrating the M-shaped bimodal flow fluctuations characteristic of the roll condition. Figure 15 The vertical axis of section (b) represents the turbine output power, showing the deep asymmetric drop curve of the turbine output power due to the gyroscopic effect.

[0146] like Figure 15The simulation results show that the pipeline flow waveform exhibits a unique M-shaped double peak with a central trough. The physical mechanism is as follows: the effective gravity acting on the vertical riser decreases periodically with rolling. When the ship passes through the absolute vertical plane (i.e., the roll angle is 0 degrees), the effective gravity instantly recovers to its maximum value, driving the flow rate to rise rapidly and form a peak. However, at this very moment, the roll angular velocity reaches its maximum value for the entire cycle, and the centrifugal resistance related to the square of the angular velocity in the momentum conservation equation also reaches its peak simultaneously. The peak caused by gravity recovery and the downward shear caused by the maximum centrifugal resistance overlap in time, resulting in a clear depression in the center of the peak. Furthermore, the high-speed spinning turbine rotor generates alternating gyroscopic torque as it follows the ship's large sway. The turbine components convert this mechanical torque into irreversible bearing friction power consumption in real time and deduct it from the thermodynamic internal work. This power consumption, combined with the square-reaction resistance characteristics caused by the acceleration and deceleration of the fluid within the pipeline, causes a deep asymmetric drop in turbine output power, demonstrating an extreme sea state efficiency loss mechanism dominated by pure thermal fluctuations and interdisciplinary rigid body mechanical losses.

[0147] Regarding the transient response characteristics under extreme sea states under multi-degree-of-freedom combined action, ship motion in the actual marine environment is often a superposition of multiple degrees of freedom motions, rather than a single existence. Therefore, in order to test the nonlinear equation analytical capability and high-frequency computation robustness of the marine condition component library under complex working conditions, three-dimensional composite dynamic excitation signals of undulation, roll, and pitch are simultaneously injected into the boundary component, and two working conditions are set respectively: one is the same-frequency multi-degree-of-freedom working condition, that is, the undulation period, roll period, and pitch period adopt the same frequency and a specific initial phase; the other is the asynchronous multi-degree-of-freedom working condition, such as setting the undulation period to 20 seconds, the roll period to 15 seconds, and the pitch period to 10 seconds.

[0148] Figure 16 This is a schematic diagram of the broadband oscillation evolution of the principal mass flow rate of a two-loop system under multi-degree-of-freedom sea states provided by the present invention. Figure 16 Part (a) shows the transient interference curves of the principal mass flow of a two-loop system under strongly coupled, multi-degree-of-freedom sea conditions with the same frequency. Figure 16 Part (b) shows the broadband evolution curve of the main mass flow rate of the two-loop system under asynchronous multi-degree-of-freedom sea state. Together, they demonstrate the intricate frequency reorganization, broadband oscillation waveform, and the slippage trend of the flow rate baseline within the fluid pipeline network under multi-degree-of-freedom superposition.

[0149] like Figure 16The simulation results show that when multiple sea state motions act on the pipeline network simultaneously, the thermal response is not a simple linear superposition of the waveforms of each single degree of freedom, but exhibits strong nonlinear interference and interdisciplinary dynamic coupling characteristics. Specifically, under the same frequency multi-degree-of-freedom condition, extremely deep troughs appear in the waveforms, which are much deeper than those under any single degree-of-freedom condition. The mechanism is that when the undulation, roll, and pitch are at the same frequency and a specific initial phase, the additional momentum source terms of each dimension, including translational overweight and weightlessness components, lateral centrifugal force components, and longitudinal tangential Euler force components, will undergo constructive interference at a specific spatial phase of the pipeline network. The reconstructed momentum conservation equation accurately captures this superposition effect of three-dimensional spatial mass force vectors. The interference causes the effective driving head of the system to be severely canceled in the local area, directly lowering the lower limit of mass flow rate pulsation. Under asynchronous multi-degree-of-freedom conditions, the flow waveform no longer exhibits the regular sinusoidal or M-shaped characteristics of single-degree-of-freedom conditions. Instead, it presents a wide-frequency, multi-peak chaotic oscillation with densely intersecting peaks and troughs. The mechanism is that momentum disturbance vectors of different frequencies and spatial directions undergo intricate redistribution and high-frequency collisions at complex fluid nodes, such as the main pipe assembly with three-dimensional flow deviation and the dynamically water-carrying steam-water separator assembly. This three-dimensional non-inertial flow field distortion is dimensionally reduced and mapped to the one-dimensional pipe network by the marine condition component library, which excites wide-frequency oscillations. The pipe network fluid is under continuous acceleration and deceleration fatigue impact.

[0150] Furthermore, such as Figure 16 Both curves show that the system under multi-degree-of-freedom conditions experienced the most severe asymmetric decline in net work efficiency and steady-state slippage of macroscopic mechanical energy. The mechanism is as follows: high-frequency chaotic oscillations amplify the square effect of nonlinear frictional resistance within the pipeline to its limit; furthermore, the turbine component's rotor rigid body dynamics model receives a multidimensional composite rocking angular velocity vector synthesized from the space of roll and pitch angular velocity vectors, and its cross-product with the rotor spin angular velocity vector produces the most severe alternating frictional torque loss in all directions; the sharp increase in thermal fluid resistance and the combined loss of mechanical rotor work result in a severe slippage of the flow rate baseline.

[0151] It should be noted that during the simultaneous solution of all transient conditions in the single-degree-of-freedom and multi-degree-of-freedom scenarios, the simulated propulsion remained smooth and stable. Even in the broadband chaotic oscillation section where the flow frequently crossed the zero point, no sudden reduction in step size, trial step dead loop, or global divergence occurred. This effectively verifies that the method provided in this application embodiment has both nonlinear equation analytical capability and high-frequency computational robustness under high-frequency multi-degree-of-freedom coupled sea conditions.

[0152] The verification results above show that the thermal-hydraulic system simulation method based on the marine condition component library provided in this application opens up a fusion channel between fluid mechanics, heat transfer, and six-degree-of-freedom rigid body kinematics at the mathematical mechanism level. It achieves high-precision and high-stability integrated solutions for alternating additional inertial forces in the ocean and transient fluctuations in the thermal-hydraulic loop, solving the technical bottleneck of the difficulty in adapting system-level one-dimensional simulation to complex three-dimensional marine environments. Compared with existing technologies, it has the following advantages: First, by introducing position vectors and direction unit vectors into the momentum conservation equation, the apparent gravity pressure drop source term induced by the multidimensional motion of the ship in space is explicitly embedded into the control equation. Rigid body kinematics theory is used to accurately synthesize the three-dimensional body forces. The three-dimensional spatial mechanical characteristics are strictly mapped to the one-dimensional solution manifold through dot product operation. At the same time, a dynamic correction coefficient is introduced into the friction pressure drop term to automatically compensate for the calculation deviation of the one-dimensional wall shear force caused by the three-dimensional slip and secondary flow phenomenon of the fluid under large inclination angles. This breaks the limitation of the traditional one-dimensional flow model that is difficult to cope with the rigid body motion in space. It enables the one-dimensional dynamic pipe to sensitively and accurately perceive the three-dimensional centrifugal sling and Coriolis deflection effect generated by the fluid as the hull sways and undulates. Secondly, by using a preset flow tolerance in the energy conservation equation to smoothly transition the windward enthalpy, the traditional step function, which is prone to causing infinite derivatives, is completely replaced. Mathematically, this ensures that the switching of the windward enthalpy when the mass flow rate crosses zero always has continuous first and second derivatives. This overcomes the problem that traditional simulation methods are prone to inducing Jacobian matrix singularity, sudden shrinkage of integral step size, or even global calculation divergence and collapse when dealing with high-frequency oscillations in marine conditions. Stable solutions without sudden shrinkage of step size are achieved in all transient conditions, such as dynamic swing verification and multi-degree-of-freedom broadband chaotic oscillations. Furthermore, by treating the two-phase region of the steam generator assembly as a thermodynamic equilibrium system with dynamic boundaries and constructing a dynamic total heat transfer coefficient, the nonlinear sharp reduction behavior of the boiling heat transfer area caused by the liquid surface tilt and exposure of the heat transfer tube bundle is fed back in real time. In addition, by abandoning the incompressibility assumption of the condenser assembly and incorporating the liquid phase volume expansion effect caused by pressure change into the dynamic evolution of the hot well liquid level, the core component of the two-phase heat exchange has the ability to physically perceive macroscopic ocean attitude changes. The continuous transition and accurate evaluation of heat transfer boundary layer distortion under sea state disturbance are realized with a purely physics-driven solution framework, which improves the computational fidelity of complex phase change processes. Furthermore, by incorporating a rotor rigid body dynamics model into the turbine assembly, the transient gyroscopic torque is calculated by real-time cross-product of the spin angular velocity vector and the transient oscillation angular velocity vector and converted into additional mechanical friction power consumption of the bearing for deduction. In addition, a dynamic pressure head compensation term containing the apparent acceleration vector is superimposed on the steady-state polynomial characteristic curve of the pump assembly. This captures the gyroscopic effect that inevitably occurs in a non-inertial rotating system. At the macroscopic level, the intrinsic physical mechanism of the dynamic loss of the effective working power of the turbine caused by complex rigid body oscillation is quantitatively explained, and the pump assembly can realistically reproduce the transient distortion of the local dynamic water pressure drop at the suction inlet caused by wave undulation. In addition, by customizing the port position vectors of each branch port for the main pipe assembly, the projection of apparent gravity on the geometric vectors of each branch port is calculated in real time to dynamically correct the back pressure of each branch. Furthermore, a dynamic water carrying capacity decay function driven by both roll or pitch angle and vertical gravity fluctuation is established for the steam-water separator assembly. This restores the amplification effect of the spatial geometric height difference of the system on the alternating solid mass force field under the real asymmetric three-dimensional compact arrangement. The macroscopic changes in ship attitude are mapped to the dynamic deterioration of the microscopic gas-liquid separation efficiency and abnormal water carrying phenomenon inside the separator. This achieves accurate analysis of the redistribution behavior of multi-degree-of-freedom disturbances at complex fluid nodes.

[0153] In summary, the thermal-hydraulic system simulation method based on the marine condition component library provided in this application, relying on the component-based encapsulation of fluid equations in non-inertial frames, the one-dimensional axial projection of three-dimensional body forces, and the smoothing mechanism of windward side specific enthalpy, breaks through the inherent bottleneck of land-based steady-state models. It provides simulation tool support with clear physical mechanisms and no numerical shrinkage defects for the optimization of three-dimensional spatial topology layout of marine nuclear energy systems under complex sea conditions, the design of system anti-sway control strategies, and the exploration of extreme operating boundaries.

[0154] The following describes the thermal-hydraulic system simulation system based on the marine condition component library provided by the present invention. The thermal-hydraulic system simulation system based on the marine condition component library described below can be referred to in correspondence with the thermal-hydraulic system simulation method based on the marine condition component library described above.

[0155] Figure 17 This is a schematic diagram of the structure of the thermal-hydraulic system simulation system based on a marine condition component library provided by the present invention; as shown below. Figure 17 As shown, the system includes: The model building module 1710 is used to determine at least one target component from the marine condition component library based on the spatial topology information of the thermal-hydraulic system to be simulated deployed on the ship, and to establish a simulation model of the thermal-hydraulic system to be simulated based on the at least one target component; each component in the marine condition component library encapsulates fluid equations in a non-inertial frame; the fluid equations include momentum conservation equations and energy conservation equations; The parameter configuration module 1720 is used to determine the component parameters of each target component based on the spatial topology information; the component parameters include a position vector relative to the motion reference point of the ship and a direction unit vector representing the direction of the component axis; The simulation module 1730 is used to solve the fluid equations of each target component in the simulation model simultaneously based on the component parameters and the six-degree-of-freedom motion boundary conditions of the ship, so as to obtain the transient thermal-hydraulic parameters of the simulated thermal-hydraulic system under marine conditions. In the simultaneous solution process, the apparent gravity pressure drop source term in the momentum conservation equation of each target component is obtained by projecting the three-dimensional bulk force through the direction unit vector of the target component to the one-dimensional axis direction of the target component; the three-dimensional bulk force is determined based on the six-degree-of-freedom motion boundary conditions, the position vector of the target component, and the flow velocity of the fluid; the windward enthalpy in the energy conservation equation of each target component is obtained by smoothing the enthalpy corresponding to the forward flow and the reverse flow of the fluid within the target component using a preset flow tolerance.

[0156] The system provided in this embodiment establishes a simulation model by determining target components from a library of ocean condition components encapsulating fluid equations in a non-inertial frame. It also configures position and orientation unit vectors for each target component, enabling the simulation model to adapt to different system spatial layouts in a modular and reusable manner, without requiring repeated modifications to the underlying code for different layouts. During the simultaneous solution process, the apparent gravity pressure drop source term is obtained by projecting the three-dimensional body forces determined based on the six-degree-of-freedom boundary conditions, position vectors, and flow velocity onto the one-dimensional axial direction via orientation unit vectors. This allows the one-dimensional fluid equations to be... Accurately sensing the differentiated mechanical effects of ship motion in three-dimensional space on target components with different spatial positions and axial orientations improves the simulation accuracy of transient thermo-hydraulic parameters under marine conditions. Furthermore, by smoothing the specific enthalpy corresponding to forward flow and reverse flow using preset flow tolerances to obtain the windward specific enthalpy, the Jacobian matrix singularity problem caused by the derivative step jump when the flow frequently crosses zero and reverses is eliminated, ensuring the numerical stability of the simultaneous solution process under extreme sea state oscillations, thereby improving the accuracy and stability of transient simulation of thermo-hydraulic systems under marine conditions.

[0157] The system provided by this invention is used to execute the above-described method embodiments. For specific processes and details, please refer to the above embodiments, which will not be repeated here.

[0158] Figure 18 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 18As shown, the electronic device may include: a processor 1810, a communications interface 1820, a memory 1830, and a communications bus 1840, wherein the processor 1810, the communications interface 1820, and the memory 1830 communicate with each other through the communications bus 1840. Processor 1810 can call logic instructions in memory 1830 to execute a simulation method for a thermal-hydraulic system based on a marine condition component library. This method includes: determining at least one target component from the marine condition component library based on the spatial topology information of the thermal-hydraulic system deployed on a ship; and establishing a simulation model of the thermal-hydraulic system based on the at least one target component. Each component in the marine condition component library encapsulates fluid equations in a non-inertial frame of reference. The fluid equations include momentum conservation equations and energy conservation equations. Based on the spatial topology information, component parameters for each target component are determined. The component parameters include a position vector relative to a motion reference point on the ship and a unit vector representing the direction of the component's axis. Based on the component parameters and the six-degree-of-freedom motion boundary conditions of the ship, the fluid equations for each target component in the simulation model are solved simultaneously to obtain the transient thermal-hydraulic parameters of the thermal-hydraulic system under marine conditions.

[0159] Furthermore, the logical instructions in the aforementioned memory 1830 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0160] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the above-described simulation method for a thermal-hydraulic system based on a marine condition component library. This method includes: determining at least one target component from a marine condition component library based on the spatial topology information of the thermal-hydraulic system to be simulated deployed on a ship, and establishing a simulation model of the thermal-hydraulic system to be simulated based on the at least one target component; each component in the marine condition component library encapsulates fluid equations in a non-inertial frame; the fluid equations include momentum conservation equations and energy conservation equations; determining component parameters of each target component based on the spatial topology information; the component parameters include a position vector relative to the motion reference point of the ship and a unit vector representing the direction of the component axis; and simultaneously solving the fluid equations of each target component in the simulation model based on the component parameters and the six-degree-of-freedom motion boundary conditions of the ship to obtain the transient thermal-hydraulic parameters of the thermal-hydraulic system to be simulated under marine conditions.

[0161] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the above-described simulation method for a thermal-hydraulic system based on a marine condition component library. This method includes: determining at least one target component from a marine condition component library based on the spatial topology information of the thermal-hydraulic system to be simulated deployed on a ship; and establishing a simulation model of the thermal-hydraulic system to be simulated based on the at least one target component; each component in the marine condition component library encapsulates fluid equations in a non-inertial frame; the fluid equations include momentum conservation equations and energy conservation equations; determining component parameters for each target component based on the spatial topology information; the component parameters include a position vector relative to a motion reference point of the ship and a unit vector representing the direction of the component's axis; and simultaneously solving the fluid equations of each target component in the simulation model based on the component parameters and the six-degree-of-freedom motion boundary conditions of the ship to obtain the transient thermal-hydraulic parameters of the thermal-hydraulic system to be simulated under marine conditions.

[0162] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0163] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0164] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A simulation method for thermal-hydraulic systems based on a marine condition component library, characterized in that, include: Based on the spatial topology information of the thermal-hydraulic system to be simulated deployed on the ship, at least one target component is determined from the marine condition component library, and a simulation model of the thermal-hydraulic system to be simulated is established based on the at least one target component; each component in the marine condition component library encapsulates fluid equations in a non-inertial frame; the fluid equations include momentum conservation equations and energy conservation equations; Based on the spatial topology information, the component parameters of each target component are determined; the component parameters include a position vector relative to the motion reference point of the ship and a direction unit vector representing the direction of the component axis; Based on the component parameters and the six-degree-of-freedom motion boundary conditions of the ship, the fluid equations of each target component in the simulation model are solved simultaneously to obtain the transient thermal-hydraulic parameters of the simulated thermal-hydraulic system under marine conditions. In the simultaneous solution process, the apparent gravity pressure drop source term in the momentum conservation equation of each target component is obtained by projecting the three-dimensional bulk force through the direction unit vector of the target component to the one-dimensional axis direction of the target component; the three-dimensional bulk force is determined based on the six-degree-of-freedom motion boundary conditions, the position vector of the target component, and the flow velocity of the fluid; the windward enthalpy in the energy conservation equation of each target component is obtained by smoothing the enthalpy corresponding to the forward flow and the reverse flow of the fluid within the target component using a preset flow tolerance.

2. The simulation method for thermal-hydraulic systems based on a marine condition component library according to claim 1, characterized in that, The apparent gravitational pressure drop source term in the momentum conservation equation for each target component is calculated based on the following steps: Based on the six-degree-of-freedom motion boundary conditions, determine the translational acceleration, angular velocity, and angular acceleration of the ship; The Euler acceleration is obtained by performing a cross product operation between the angular acceleration and the position vector of the target component. The centrifugal acceleration is obtained by performing a cross product operation between the angular velocity and the position vector of the target component, and then performing a cross product operation between the result of the cross product operation and the angular velocity. The angular velocity is cross-multiplied with the flow velocity of the fluid inside the target component, and the Coriolis acceleration is obtained based on the cross-multiplication result. The total acceleration is obtained by summing the translational acceleration, the Euler acceleration, the centrifugal acceleration, and the Coriolis acceleration. The three-dimensional body force is determined based on the difference between the gravitational acceleration and the total acceleration. The three-dimensional mass force is projected onto the one-dimensional axis direction of the target component through the unit vector of the target component to obtain the apparent gravitational pressure drop source term in the momentum conservation equation of the target component.

3. The simulation method for thermal-hydraulic systems based on a marine condition component library according to claim 1, characterized in that, In the simultaneous solution process, the frictional pressure drop term in the momentum conservation equation for each target component is calculated based on the following steps: The reference frictional pressure drop is determined based on the friction coefficient along the path, the length, diameter, flow cross-sectional area of ​​the target component, the density of the fluid inside the target component, and the transient mass flow vector. The ship's tilt angle is determined based on the six-degree-of-freedom motion boundary conditions. The dynamic correction factor is determined based on the ship's inclination angle; The reference frictional pressure drop is corrected according to the dynamic correction coefficient to obtain the frictional pressure drop term in the momentum conservation equation of the target component; The dynamic correction coefficient is used to compensate for the calculation deviation of the wall shear force when the ship is in a tilted state.

4. The simulation method for thermal-hydraulic systems based on a marine condition component library according to any one of claims 1-3, characterized in that, The target component includes a main pipe component; the component parameters of the main pipe component also include the port position vector of each branch port relative to the central node of the main pipe component; In the process of solving the simultaneous equations, the momentum conservation equations of the target components connected to each of the branch ports are solved simultaneously with the back pressure of the branch ports as the pressure boundary. The back pressure of each branch port is calculated based on the following steps: Based on the six-degree-of-freedom motion boundary conditions, determine the real-time apparent gravitational acceleration; The real-time apparent gravitational acceleration is multiplied by the position vector of each port, and the deflection head of each branch port is determined based on the result of the dot product and the density of the fluid in the main pipe assembly. The back pressure of each branch port is determined based on the pressure of the central node and the deflection head of each branch port.

5. The simulation method for thermal-hydraulic systems based on a marine condition component library according to any one of claims 1-3, characterized in that, The target component includes a steam-water separator assembly; In the process of solving the simultaneous equations, the mass flow distribution between the vapor phase outlet and the liquid phase outlet in the mass conservation equation of the steam-water separator assembly, and the outlet specific enthalpy of the vapor phase outlet in the energy conservation equation of the steam-water separator assembly, are all determined based on the transient water carrying capacity of the steam-water separator assembly. The transient water carrying capacity is calculated based on the following steps: Based on the six-degree-of-freedom motion boundary conditions, determine the ship's tilt angle and the gravity deviation of the vertical apparent gravity from the reference gravity. The tilt correction amount is determined based on the tilt sensitivity coefficient and the sine value of the tilt angle; The gravity fluctuation correction amount is determined based on the gravity fluctuation sensitivity coefficient and the ratio between the gravity deviation and the reference gravity. The rated water carrying capacity of the steam-water separator assembly is corrected based on the tilt correction amount and the gravity fluctuation correction amount to obtain the transient water carrying capacity.

6. The simulation method for thermal-hydraulic systems based on a marine condition component library according to any one of claims 1-3, characterized in that, The target component includes a steam generator assembly, and the fluid equations of the steam generator assembly also include the pressure conservation equation and the heat transfer coefficient equation. In the process of solving the simultaneous equations, the transient pressure change rate in the pressure conservation equation and the dynamic total heat transfer coefficient in the heat transfer coefficient equation are calculated based on the following steps: The first mass change term is determined based on the liquid phase volume of the steam generator assembly, the partial derivative of the saturated liquid density with respect to the saturated liquid enthalpy, and the rate of change of the saturated liquid enthalpy. The second mass change term is determined based on the vapor phase volume of the steam generator assembly, the partial derivative of the saturated vapor density with respect to the saturated vapor enthalpy, and the rate of change of the saturated vapor enthalpy. The transient pressure change rate is calculated based on the inlet mass flow rate, outlet mass flow rate, first mass change term, second mass change term, the product of the liquid phase volume and the partial derivative of the saturated liquid density with respect to pressure, and the product of the vapor phase volume and the partial derivative of the saturated vapor density with respect to pressure of the steam generator assembly. The ship's tilt angle is determined based on the six-degree-of-freedom motion boundary conditions. The heat transfer area attenuation function value is determined based on the ship's inclination angle and the liquid level in the steam generator assembly. The dynamic overall heat transfer coefficient is determined based on the rated overall heat transfer coefficient, the heat transfer area decay function value, and the ratio between the real-time mass flow rate of the primary side and the rated mass flow rate of the primary side.

7. The simulation method for thermal-hydraulic systems based on a marine condition component library according to any one of claims 1-3, characterized in that, The target component includes a condenser assembly; the fluid equation of the condenser assembly also includes a liquid level differential equation. In the process of solving the simultaneous equations, the rate of change of hot well liquid level in the liquid level differential equation is calculated based on the following steps: The liquid phase volume expansion correction is determined based on the transient pressure change rate, liquid phase volume, and partial derivative of liquid phase density with respect to pressure within the condenser assembly. The net change in the mass of the hot well is determined based on the difference between the condensation and outflow of the condenser assembly and the liquid phase volume expansion correction. The rate of change of hot well liquid level is determined based on the net change in the mass of the hot well, the liquid phase density of the fluid in the condenser assembly, and the cross-sectional area of ​​the hot well.

8. The simulation method for thermal-hydraulic systems based on a marine condition component library according to any one of claims 1-3, characterized in that, The target component includes a pump assembly; the fluid equations for the pump assembly also include an effective head equation; In the process of solving the simultaneous equations, the effective pressure head in the effective pressure head equation is calculated based on the following steps: The steady-state head of the pump assembly is determined based on the characteristic curve fitting coefficient, volumetric flow rate, and transient rotational angular velocity of the pump assembly. Based on the six-degree-of-freedom motion boundary conditions, determine the apparent acceleration of the ship; The dynamic head compensation term is determined based on the directional unit vector of the pump assembly, the apparent acceleration, and the density of the fluid within the pump assembly. The effective pressure head is determined based on the steady-state pressure head and the dynamic pressure head compensation term.

9. The simulation method for thermal-hydraulic systems based on a marine condition component library according to any one of claims 1-3, characterized in that, The target component includes a steam turbine assembly; the fluid equations of the steam turbine assembly also include work equations; In the process of solving the simultaneous equations, the work term in the work equation is calculated based on the following steps: Based on the six-degree-of-freedom motion boundary conditions, determine the transient yaw rate of the ship; The rotor spin angular velocity of the turbine assembly is cross-multiplied with the transient oscillation angular velocity, and the transient gyro torque is determined based on the cross-multiplication result and the rotor moment of inertia of the turbine assembly. Based on the transient gyro torque, determine the additional mechanical frictional power consumption of the bearing system acting on the turbine assembly; The theoretical output power of the turbine assembly is determined based on the inlet steam mass flow rate, isentropic enthalpy drop, and isentropic efficiency of the turbine assembly. The work item is determined based on the difference between the theoretical output power and the additional mechanical friction power consumption.

10. A simulation system for thermal-hydraulic systems based on a marine condition component library, characterized in that, include: The model building module is used to determine at least one target component from the marine condition component library based on the spatial topology information of the thermal-hydraulic system to be simulated deployed on the ship, and to establish a simulation model of the thermal-hydraulic system to be simulated based on the at least one target component; each component in the marine condition component library encapsulates fluid equations in a non-inertial frame; the fluid equations include momentum conservation equations and energy conservation equations; The parameter configuration module is used to determine the component parameters of each target component based on the spatial topology information; the component parameters include a position vector relative to the motion reference point of the ship and a direction unit vector representing the direction of the component axis; The simulation module is used to solve the fluid equations of each target component in the simulation model simultaneously based on the component parameters and the six-degree-of-freedom motion boundary conditions of the ship, so as to obtain the transient thermal-hydraulic parameters of the simulated thermal-hydraulic system under marine conditions. In the simultaneous solution process, the apparent gravity pressure drop source term in the momentum conservation equation of each target component is obtained by projecting the three-dimensional bulk force through the direction unit vector of the target component to the one-dimensional axis direction of the target component; the three-dimensional bulk force is determined based on the six-degree-of-freedom motion boundary conditions, the position vector of the target component, and the flow velocity of the fluid; the windward enthalpy in the energy conservation equation of each target component is obtained by smoothing the enthalpy corresponding to the forward flow and the reverse flow of the fluid within the target component using a preset flow tolerance.

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