Method of monitoring a steam generator and device therefor

Abstract

This application provides a monitoring method and apparatus for a steam generator. The method includes: constructing a simulation model of the steam generator; inputting real-time parameters of the steam generator into the simulation model to obtain the wall temperature distribution parameters, heat flux density distribution parameters, and coordinates of the current operating condition of the steam generator on a stability boundary diagram; determining the heat transfer deterioration safety margin of the characteristic tube based on the wall temperature distribution parameters, and determining the shortest distance between the coordinates and the stability boundary line; determining the target confidence level based on the heat flux density distribution parameters; determining the risk level of the steam generator based on the heat transfer deterioration safety margin and the shortest distance; and outputting early warning information for the steam generator based on the risk level and the target confidence level. This application ensures the safety of the steam generator after its operating parameters are increased to the supercritical or near-critical pressure region.

Description

Technical Field

[0001] This application relates to the field of nuclear power technology, and in particular to a monitoring method and apparatus for a steam generator. Background Technology

[0002] In nuclear power systems, the steam generator serves as a crucial link between the liquid metal in the primary loop and the water in the secondary loop. The thermal-hydraulic performance of the steam generator directly determines the energy conversion efficiency and operational safety of the entire system.

[0003] With the rapid development of supercritical Brayton cycle technology, raising the operating parameters of steam generators to the supercritical or near-critical pressure region has become a forward-looking strategic direction for significantly improving the power generation efficiency of nuclear power systems. However, this leap in operating parameters brings unprecedented technical challenges. Under high-parameter conditions, the physical properties of the working fluid (supercritical water) inside the tube change drastically, especially near the quasi-critical point, where key physical properties such as density, specific heat capacity, and thermal conductivity exhibit nonlinear abrupt changes with temperature. Simultaneously, the liquid outside the steam generator tubes typically maintains a high temperature of several hundred degrees Celsius, creating a significant temperature difference driving potential with the fluid inside the tubes. This complex multiphysics coupling effect, under the influence of the unique geometry of the helical tube, makes the flow and heat transfer mechanism inside and outside the tube extremely complex, easily inducing local heat transfer deterioration and density wave flow instability.

[0004] In the exemplary technology, the monitoring of the steam generator is carried out when the steam generator is under subcritical pressure parameters. However, the monitoring of the steam generator under heat transfer deterioration is not involved. That is, after the operating parameters of the steam generator are increased to the supercritical or near-critical pressure region, the heat transfer deterioration of the steam generator cannot be detected. The safety of the steam generator cannot be guaranteed after the operating parameters of the steam generator are increased to the supercritical or near-critical pressure region. Summary of the Invention

[0005] Based on the above-mentioned technological status, this application provides a monitoring method and device for a steam generator, which is used to solve the problem that the safety of the steam generator cannot be guaranteed after the operating parameters of the steam generator are increased to the supercritical or near-critical pressure region.

[0006] To achieve the above-mentioned technical objectives, this application proposes the following technical solution: In a first aspect, this application provides a method for monitoring a steam generator, including: Based on the property parameters of the characteristic tubes in the steam generator and the thermal-hydraulic parameters, a simulation model corresponding to the steam generator is constructed. The real-time parameters collected by the steam generator are input into the simulation model for simulation, and the wall temperature distribution parameters, heat flux density distribution parameters, and coordinates of the current operating condition of the steam generator on the stability boundary diagram are obtained. If the steam generator is determined to be in a state of heat transfer deterioration based on the wall temperature distribution parameters, the heat transfer deterioration safety margin of the characteristic tube is determined based on the wall temperature distribution parameters, and the shortest distance between the coordinate point and the stability boundary line is determined. The target confidence level is determined based on the heat flux density distribution parameters, and the risk level of the steam generator is determined based on the heat transfer deterioration safety margin and the shortest distance. The warning information of the steam generator is output based on the risk level and the target confidence level.

[0007] In some implementations, determining the risk level of the steam generator based on the heat transfer degradation safety margin and the shortest distance includes: Based on the real-time parameters, the reduced velocity and vibration amplitude of the steam generator are determined; The risk level of the steam generator is determined based on the reduction rate, the vibration amplitude, the heat transfer deterioration safety margin, and the shortest distance.

[0008] In some embodiments, constructing a simulation model of the steam generator based on the property parameters of the characteristic tubes and the thermo-hydraulic parameters includes: Based on the property parameters of the characteristic tubes and the thermal-hydraulic parameters in the steam generator, construct the spatial model corresponding to the steam generator; The spatial model is reduced in order to obtain the simulation model.

[0009] In some embodiments, determining the target confidence level based on the heat flux density distribution parameter includes: The critical heat flux density parameters of the steam generator are obtained based on the critical heat flux density model. The heat flux margin is determined based on the critical heat flux density parameter and the heat flux density distribution parameter. The target confidence level is determined based on the heat flux density margin.

[0010] In some implementations, it also includes: The heat exchange efficiency of the steam generator is determined based on the real-time parameters. Based on the heat exchange efficiency and the pressure drop parameters collected by the steam generator, the performance degradation parameters of the steam generator are determined, and the performance prompt information of the steam generator is output according to the performance degradation parameters.

[0011] In some embodiments, determining the heat exchange efficiency of the steam generator based on the real-time parameters includes: Based on the simulation model, the steam generator is simulated to obtain multiple simulation parameters of the steam generator in its operating state; The heat exchange efficiency of the steam generator is determined based on the simulation parameters and real-time parameters.

[0012] In some embodiments, after inputting the real-time parameters collected by the steam generator into the simulation model for simulation, the method further includes: Based on the wall temperature distribution parameters, the temperature fluctuation parameters are determined, and based on the temperature fluctuation parameters, the first change parameter of thermal strain is determined; The second variation parameter of mechanical strain is determined based on the vibration amplitude of the steam generator; Based on the first and second changing parameters, the total changing parameters are determined, and the remaining service life of the steam generator is determined based on the total changing parameters. Based on the remaining service life, output maintenance recommendations for the steam generator.

[0013] In some embodiments, determining the first change parameter of thermal strain based on the temperature fluctuation parameter includes: The initial variation parameters of thermal strain are determined based on the temperature fluctuation parameters. Based on the multi-axis constraint relationship of the feature tube, the initial variation parameters are corrected to obtain the first variation parameters.

[0014] In some embodiments, constructing a simulation model of the steam generator based on the property parameters of the characteristic tubes and the thermo-hydraulic parameters includes: Based on the property parameters and thermal-hydraulic parameters of the characteristic tube in the steam generator, a first spatial model corresponding to the characteristic tube is constructed. Based on the phase change process of the liquid in the feature tube in the flow direction, the first spatial model is divided into multiple flow regions, and based on the characteristics of the liquid in the feature tube in the flow region, a first correlation between heat transfer and pressure drop in the flow region is constructed to obtain the second spatial model. Based on the material properties of the feature tube and the flow characteristics of the liquid outside the feature tube, a second correlation relationship for heat transfer outside the tube in the second spatial model is constructed to obtain a third spatial model. The simulation model is obtained by iteratively solving the first and second correlation relationships of the third spatial model.

[0015] Secondly, this application provides a monitoring device for a steam generator, comprising: The construction module is used to construct a simulation model of the steam generator based on the property parameters of the characteristic tubes and the thermal-hydraulic parameters in the steam generator. The input module is used to input the real-time parameters collected by the steam generator into the simulation model for simulation, and to obtain the wall temperature distribution parameters, heat flux density distribution parameters and the coordinate points of the current operating condition of the steam generator on the stability boundary diagram. The first determining module is used to determine the heat transfer degradation safety margin of the characteristic tube based on the wall temperature distribution parameters when the steam generator is determined to be in a state of heat transfer degradation based on the wall temperature distribution parameters, and to determine the shortest distance between the coordinate point and the stability boundary line. The second determining module is used to determine the target confidence level based on the heat flux density distribution parameters, and to determine the risk level of the steam generator based on the heat transfer deterioration safety margin and the shortest distance, and to output the early warning information of the steam generator based on the risk level and the target confidence level.

[0016] This application provides a monitoring method and apparatus for a steam generator. A simulation model of the steam generator is constructed based on the property parameters of characteristic tubes and thermo-hydraulic parameters. Real-time parameters collected by the steam generator are input into the simulation model for simulation. The wall temperature distribution parameters, heat flux density distribution parameters, and coordinates of the current operating condition of the steam generator on the stability boundary map are obtained. If the steam generator is determined to be in a state of heat transfer deterioration based on the wall temperature distribution parameters, the heat transfer deterioration safety margin of the characteristic tubes is determined based on the wall temperature distribution parameters, and the shortest distance between the coordinates and the stability boundary line is determined. A target confidence level is determined through the heat flux density distribution parameters, and the risk level of the steam generator is determined based on the heat transfer deterioration safety margin and the shortest distance. Therefore, early warning information for the steam generator is output based on the risk level and the target confidence level. In this application, the wall temperature distribution parameters and heat flux density distribution parameters of the characteristic tubes that cannot be collected by the steam generator are determined by the simulation model of the steam generator, as well as the coordinate points of the current operating condition of the steam generator on the stability boundary diagram. Based on the wall temperature distribution parameters, it is determined whether the steam generator is in a state of heat transfer deterioration. If the steam generator is in a state of heat transfer deterioration, the warning information containing the risk level is output through the wall temperature distribution parameters, heat flux density distribution parameters, and coordinate points. This allows maintenance personnel to deal with the heat transfer deterioration of the steam generator in a timely manner based on the warning information, ensuring the safety of the steam generator after its operating parameters are increased to the supercritical or near-critical pressure region. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application 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 only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 A flowchart of a steam generator monitoring method provided in this application embodiment. Figure 1 .

[0019] Figure 2 A flowchart of a steam generator monitoring method provided in this application embodiment. Figure 2 .

[0020] Figure 3 A flowchart of a steam generator monitoring method provided in this application embodiment. Figure 3 .

[0021] Figure 4 A flowchart of a steam generator monitoring method provided in this application embodiment. Figure 4 .

[0022] Figure 5 A flowchart of a steam generator monitoring method provided in this application embodiment. Figure 5 .

[0023] Figure 6 This is a schematic diagram of the functional modules of a monitoring device for a steam generator provided in an embodiment of this application.

[0024] Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] In nuclear power systems, the steam generator serves as a crucial link between the liquid metal in the primary loop and the water in the secondary loop. The thermal-hydraulic performance of the steam generator directly determines the energy conversion efficiency and operational safety of the entire system.

[0027] With the rapid development of supercritical Brayton cycle technology, raising the operating parameters of steam generators to the supercritical or near-critical pressure region has become a forward-looking strategic direction for significantly improving the power generation efficiency of nuclear power systems. However, this leap in operating parameters brings unprecedented technical challenges. Under high-parameter conditions, the physical properties of the working fluid (supercritical water) inside the tube change drastically, especially near the quasi-critical point, where key physical properties such as density, specific heat capacity, and thermal conductivity exhibit nonlinear abrupt changes with temperature. Simultaneously, the liquid outside the steam generator tubes typically maintains a high temperature of several hundred degrees Celsius, creating a significant temperature difference driving potential with the fluid inside the tubes. This complex multiphysics coupling effect, under the influence of the unique geometry of the helical tube, makes the flow and heat transfer mechanism inside and outside the tube extremely complex, easily inducing local heat transfer deterioration and density wave flow instability.

[0028] In the exemplary technology, the monitoring of the steam generator is carried out when the steam generator is under subcritical pressure parameters. However, the monitoring of the steam generator under heat transfer deterioration is not involved. That is, after the operating parameters of the steam generator are increased to the supercritical or near-critical pressure region, the heat transfer deterioration of the steam generator cannot be detected. The safety of the steam generator cannot be guaranteed after the operating parameters of the steam generator are increased to the supercritical or near-critical pressure region.

[0029] Furthermore, the exemplary technique separates thermal-hydraulic analysis, heat transfer deterioration research, and flow instability research into independent analytical dimensions, without establishing the coupling relationship between the three.

[0030] Deterioration in heat transfer is often accompanied by changes in the local flow structure, which may trigger flow instability; conversely, flow oscillations can also affect the heat transfer intensity in the near-wall region, altering the threshold for heat transfer deterioration. This two-way coupling mechanism has not yet been revealed by existing models.

[0031] The high temperature of the liquid metal outside the steam generator tube and the low temperature of the supercritical water inside the tube create a huge temperature difference driving potential. In the exemplary technology, when dealing with the boundary conditions, the simplified assumption of uniform heat flux density or isothermal boundary is often used, which fails to realize the heat flux coupling between the lead-bismuth flow heat transfer outside the tube and the supercritical water flow heat transfer inside the tube, resulting in the calculation results deviating from reality.

[0032] In addition, the operation and maintenance of tube steam generators mainly rely on periodic maintenance, which has the following shortcomings: The internal state of the steam generator cannot be perceived: The high temperature, high pressure and strong radiation service environment make it difficult to directly measure key internal parameters (such as local inner wall temperature and local heat flux density distributed along the pipe length) through sensors. Operators cannot grasp the real margin of the equipment from the heat transfer deterioration boundary and safety limit in real time.

[0033] The remaining lifespan of steam generators cannot be dynamically predicted. Exemplary lifespan assessment methods are mostly based on fixed load assumptions made during the design phase, and cannot dynamically update fatigue damage accumulation according to the temperature fluctuation history during actual operation, making it difficult to accurately predict the remaining usable time of the equipment.

[0034] Steam generator operation and maintenance decisions lack intelligent support. When abnormal parameters are detected, only alarm signals can be provided, without offering actionable control adjustment suggestions, let alone linking condition assessment with maintenance plan formulation. This makes it difficult to meet the "predictive maintenance" requirements of future smart nuclear power systems.

[0035] To address the aforementioned technical problems, this application proposes a monitoring method for a steam generator. The following detailed description of the monitoring method for a steam generator proposed in this application is provided through various embodiments.

[0036] Reference Figure 1 , Figure 1 A flowchart of a steam generator monitoring method provided in this application embodiment. Figure 1 .like Figure 1 As shown, the monitoring method for a steam generator provided in this embodiment includes: Step S101: Construct a simulation model of the steam generator based on the property parameters of the characteristic tubes and the thermal-hydraulic parameters in the steam generator.

[0037] In this embodiment, the executing entity is the monitoring device of the steam generator. For ease of description, the term "device" will be used to refer to the monitoring device of the steam generator below. The device can be any terminal device with monitoring functions, or it can be a device used to monitor the steam generator in a nuclear power system.

[0038] Nuclear power systems are equipped with steam generators. Simulation models of the steam generator can be constructed using the property parameters of its characteristic tubes and thermal-hydraulic parameters. Characteristic tubes refer to heat exchange tubes with unique structural features, created through machining of special geometric shapes such as grooves, corrugations, threads, fins, and T-slots on their inner and outer surfaces. These characteristic tubes disrupt the fluid flow by utilizing the uneven structure of their walls, breaking the static heat transfer boundary layer and forcing turbulence, thus significantly improving the heat exchange capacity of the hot and cold media. All tubes in a steam generator with inner or outer wall patterns, grooves, corrugations, or other irregular shapes used to enhance heat transfer are referred to as characteristic tubes.

[0039] The attribute parameters include the macroscopic parameters of the tube bundle, the geometric parameters of a single tube, and the attribute parameters of the tube material.

[0040] Macroscopic parameters of the tube bundle: tube arrangement (equilateral triangle / square arrangement), tube spacing (Typically 1.2–1.5 times the outer diameter of the pipe), helix angle (Typical value 5°–15°), helix diameter (Typically 10–30 times the outer diameter of the pipe), total number of spiral turns .

[0041] Single-tube geometric parameters: inner diameter , tube outer diameter Manager curvature ratio The curvature ratio is a key parameter for measuring the degree of helical bending. The more severe the bending, the stronger the secondary flow induced by centrifugal force, and the better the heat exchange effect.

[0042] Pipe material properties: Pipe density thermal conductivity (As temperature changes, refer to tables according to pipe grade or use polynomial fitting), specific heat capacity Coefficient of thermal expansion .

[0043] Thermal-hydraulic parameters include the frictional pressure drop of the characteristic pipe. Accelerate pressure drop and gravitational pressure drop Furthermore, if the characteristic tube is a spiral tube, the frictional pressure drop dominates, requiring the introduction of a spiral correction factor. Additionally, the thermal-hydraulic parameters also include the external heat transfer coefficient and the internal heat transfer coefficient of the characteristic tube.

[0044] In the first example, based on the design drawings of the steam generator, a set of parameters (attribute parameters and thermal-hydraulic parameters) that can uniquely determine the geometric features and operating boundaries of the equipment are extracted to establish a model of the steam generator as a simulation model.

[0045] In the second example, a spatial model of the steam generator is constructed based on the attribute parameters and thermo-hydraulic parameters of the characteristic pipes within the steam generator. Specifically, a set of parameters (attribute parameters and thermo-hydraulic parameters) that uniquely determine the geometric features and operating boundaries of the equipment are extracted from the steam generator's design drawings to establish the spatial model. After obtaining the spatial model, it undergoes order reduction processing to obtain a simulation model. The simulation model retains the high accuracy of the spatial model, but the order reduction process significantly increases the computational speed by several orders of magnitude, enabling real-time operation and rapid simulation of the steam generator to obtain results. Intrinsic orthogonal decomposition or artificial neural networks can be used to reduce the order of the spatial model. In this example, the order-reduced simulation model significantly improves the data computation rate compared to the unreduced model, increasing the data computation speed by several orders of magnitude.

[0046] Step S102: Input the real-time parameters collected by the steam generator into the simulation model for simulation to obtain the wall temperature distribution parameters, heat flux density distribution parameters of the characteristic tubes in the steam generator, and the coordinates of the current operating conditions of the steam generator on the stability boundary diagram.

[0047] After determining the simulation model, the real-time parameters of the steam generator are obtained and input into the simulation model for simulation, thereby obtaining parameters of the steam generator that cannot be directly measured, specifically including the wall temperature distribution parameters of the characteristic tubes. Heat flux density distribution parameters and the coordinates of the current operating conditions of the steam generator on the stability boundary diagram. , ).

[0048] Wall temperature distribution parameters It includes the temperature of each point on the feature tube, that is, the temperature of each point represents the wall temperature of a point in the feature tube.

[0049] Stability boundary diagrams are plotted based on the phase transition number and the degree of supercooling. For example, the horizontal axis represents the phase transition number. : ;in, Total heating power, in [W]; The latent heat of vaporization is expressed in [J / kg]. This represents the specific volume difference between vapor and liquid phase transitions, expressed in [m³ / kg]. The specific volume of the saturated liquid is expressed in [m³ / kg].

[0050] The vertical axis represents the degree of supercooling. : ;in, This is the saturated liquid specific enthalpy corresponding to the inlet pressure of the steam generator, in units of [J / kg]. This is the actual specific enthalpy at the inlet of the steam generator, expressed in [J / kg].

[0051] Stability boundary diagrams were drawn using the degree of supercooling and phase transition number under different operating conditions.

[0052] Step S103: If the steam generator is determined to be in a state of heat transfer deterioration based on the wall temperature distribution parameters, determine the safety margin of heat transfer deterioration of the characteristic tube based on the wall temperature distribution parameters, and determine the shortest distance between the coordinate point and the stability boundary line.

[0053] The device determines whether the steam generator is in a state of deteriorating heat transfer based on wall temperature distribution parameters. For example, the device needs to determine whether the wall temperature gradient between adjacent monitoring points along the length of the characteristic tube exceeds a threshold, i.e., whether the conditions are met. , ℃ / m, Characterizes the wall temperature gradient. If... It is also necessary to determine whether the local wall temperature exceeds the material's safety threshold. ,Right now If both conditions are met as well as This indicates that the steam generator is in a state of deteriorating heat transfer, and this situation can be defined as the onset point of heat transfer deterioration. .

[0054] To address this, the device determines the safety margin for heat transfer degradation of the characteristic tube based on the wall temperature distribution parameters, that is, it calculates the safety margin for heat transfer degradation at each location along the tube length. Specifically: ;in, The reference temperature is usually taken as the initial wall temperature at the tube bundle inlet and the typical wall temperature under normal rated operating conditions, as the starting point for margin calculation.

[0055] The device determines the shortest distance between coordinate points and the stability boundary line. For example, the stability boundary line is determined based on the degree of undercooling and the phase transition number, at different ( , Perform eigenvalue scanning at the operating points and mark stability transition points. Recommended calculation step size. Encrypt to 0.02 near the boundary. Connecting the points yields the stability boundary line. This represents the maximum perturbation growth rate. For example, the characteristic equation is: Solve for the characteristic roots of this characteristic equation. If the real parts of all characteristic roots are If the steam generator is stable, then the steam generator is stable. If any... If it exists, it is unstable. and It is at a critical point of stability. The imaginary part represents the natural angular frequency of the j-th mode.

[0056] The shortest distance D_inst refers to To the stable boundary line ( The shortest Euclidean distance of a point set can be expressed as: ;in, The critical subcooling number. For example, the physical meaning of the shortest distance is shown in Table-1: Table 1:

[0057] Step S104: Determine the target confidence level based on the heat flux density distribution parameters, and determine the risk level of the steam generator based on the heat transfer deterioration safety margin and the shortest distance. Output the early warning information of the steam generator based on the risk level and the target confidence level.

[0058] In this embodiment, the device needs to determine the target confidence level based on the heat flux density distribution parameters. The target confidence level serves as a supplementary verification indicator for the safety margin of heat transfer deterioration.

[0059] In one example, after calculating the heat flux density distribution parameters, the simulation model calculates the confidence level based on the heat flux density distribution parameters. Therefore, the simulation model outputs the heat flux density distribution parameters and their associated confidence levels, and the device uses the confidence level associated with the heat flux density distribution parameters as the target confidence level.

[0060] In another example, the device determines the target confidence level based on heat flux density distribution parameters. For instance, the device establishes a critical heat flux density model. The critical heat flux density... Defined as: under given operating conditions (mass flow rate) ,pressure curvature ratio Under these conditions, the critical value at which the heat flux density reaches the point where the dual criterion for heat transfer deterioration is first triggered is essentially the boundary mapping of the dual criterion in the heat flux density-operating condition parameter space. Specifically, through the parameter space... During variable operating condition scanning calculations, the heat flux density is gradually increased until the dual criteria are triggered. The critical values ​​are recorded and the function form is obtained by fitting the data. ,in, Follow Increase and increase (high flow rate enhances heat transfer), with The value decreases significantly as it approaches the critical point (the abrupt change in physical properties intensifies in the quasi-critical region), and with... Increased by curvature-induced secondary flow enhances heat transfer, i.e., the critical heat flux density model is achieved through... Characterization is performed. The device obtains the critical heat flux density parameters of the steam generator based on the critical heat flux density model, and determines the heat flux density margin using the critical heat flux density parameters and heat flux density distribution parameters. The target confidence level is then determined based on the heat flux density margin. Heat flux density margin : ;in, For heat flux density parameters, This refers to the heat flux density distribution parameter.

[0061] When the heat flux density margin The target confidence level is high confidence. The target will have a medium confidence level.

[0062] The device determines the risk level of the steam generator based on the safety margin for heat transfer degradation and the shortest distance.

[0063] For example, risk levels can be divided into multiple levels, such as Level 1, Level 2, Level 3, and Level 4, with risk increasing sequentially. Furthermore, each level can also be represented by color, such as four levels with increasing risk: green (normal), yellow (caution), orange (alarm), and red (emergency). For example, if the minimum safety margin for heat transfer deterioration at each location in the characteristic tube... And the shortest distance If the risk level is green, then the risk level is green; if lie in – and / or If the value is between 0.1 and 0.2, the risk level is yellow; if lie in – and / or If the value is between 0.05 and 0.1, the risk level is orange; if Less than and / or A value less than 0.05 indicates a red risk level. It should be noted that the thresholds used to determine the risk level can be set as needed, such as... The thresholds (0.20, 0.10, 0.05) correspond to - Coordinates of the points on the stability boundary diagram The dimensionless distance of the stable boundary line.

[0064] After determining the risk level, early warning information for the steam generator is determined based on the risk level and target confidence level. For example, if the risk level is green, regardless of whether the target confidence level is high or medium, the early warning information could be "Steam generator is operating normally." If the risk level is yellow and the target confidence level is high, the early warning information could be "Strengthen monitoring and record abnormal trends." If the risk level is yellow and the target confidence level is medium, the early warning information could be "It is recommended to calibrate the sensors." If the risk level is orange and the target confidence level is high, the early warning information could be "Please have operators intervene to adjust the feedwater flow or reduce the load," etc. If the risk level is orange and the target confidence level is medium, the early warning information could be "It is recommended to adjust xx and verify whether the adjustment method is appropriate." If the risk level is red and the target confidence level is high, the early warning information could be "The steam generator has been automatically protected; please take immediate measures to maintain the steam generator." If the risk level is red and the target confidence level is high, the early warning information could be "The steam generator has been automatically protected; please first check whether the sensors are normal. If abnormal, take measures to maintain the steam generator."

[0065] Upon receiving a warning message, the system outputs the warning message. This can be done by displaying the warning message on the device's screen or by sending the warning message to a terminal associated with maintenance personnel.

[0066] In this embodiment, a simulation model of the steam generator is constructed based on the property parameters of the characteristic tubes and the thermo-hydraulic parameters. The real-time parameters collected by the steam generator are input into the simulation model for simulation, and the wall temperature distribution parameters, heat flux density distribution parameters, and coordinates of the current operating conditions of the steam generator on the stability boundary map are obtained. When the steam generator is determined to be in a state of heat transfer deterioration based on the wall temperature distribution parameters, the heat transfer deterioration safety margin of the characteristic tubes is determined based on the wall temperature distribution parameters, and the shortest distance between the coordinate points and the stability boundary line is determined. The target confidence level is determined through the heat flux density distribution parameters, and the risk level of the steam generator is determined based on the heat transfer deterioration safety margin and the shortest distance. Thus, the early warning information of the steam generator is output based on the risk level and the target confidence level. In this embodiment, the wall temperature distribution parameters, heat flux density distribution parameters, and coordinates of the current operating condition of the steam generator on the stability boundary diagram are determined by the simulation model of the steam generator, which are not collectable characteristic tubes. Based on the wall temperature distribution parameters, it is determined whether the steam generator is in a state of heat transfer deterioration. If the steam generator is in a state of heat transfer deterioration, the warning information containing the risk level is output through the wall temperature distribution parameters, heat flux density distribution parameters, and coordinates. This allows maintenance personnel to deal with the heat transfer deterioration of the steam generator in a timely manner based on the warning information, ensuring the safety of the steam generator after its operating parameters are increased to the supercritical or near-critical pressure region.

[0067] Reference Figure 2 , Figure 2 A flowchart of a steam generator monitoring method provided in this application embodiment. Figure 2 ,based on Figure 1 In the embodiment shown, step S104 includes: Step S201: Determine the reduced speed and vibration amplitude of the steam generator based on real-time parameters.

[0068] In this embodiment, the steam generator is a spiral tube type direct-flow steam generator. This type of steam generator is subjected to the lateral scouring of high-temperature liquid metal for a long time, and the tube bundle will inevitably be induced to undergo hydrodynamic vibration. If the flow-induced vibration is not controlled, it may lead to fretting wear of the tube bundle and reduced fatigue life, or even cause heat transfer tube breakage failure. Therefore, in addition to the criteria of heat transfer deterioration safety margin and flow instability (determined by the shortest distance), it is also necessary to conduct risk assessment through flow-induced vibration.

[0069] To address this, the device determines the reduction rate using real-time parameters of the steam generator. , , It refers to the lateral inflow velocity of the fluid at the tube bundle gap, which is also one of the real-time parameters; This refers to the inherent frequency of a single heat transfer tube; This refers to the outer diameter of the characteristic tube. It is the primary dimensionless number for determining the type of vibration. At lower levels, vortex-induced vibration is dominant. At higher levels, this may trigger ricochet instability. The device also needs to determine the vibration amplitude based on real-time parameters. Vibration amplitude refers to the root mean square value of the displacement of the steam generator's pipes. Specifically, , Let be the vibration response function. For mass ratio, For the damping ratio, Characterizing the vibration resistance of the tube bundle, The larger the tube, the less likely it is to vibrate significantly.

[0070] Step S202: Determine the risk level of the steam generator based on the reduced speed, vibration amplitude, heat transfer deterioration safety margin, and shortest distance.

[0071] After determining the reduced velocity and vibration amplitude, the risk level of the steam generator is determined based on the reduced velocity, vibration amplitude, heat transfer deterioration safety margin, and shortest distance.

[0072] For example, using risk levels as colors, if , and If so, the risk level is green. For the critical reduction rate, The maximum permissible vibration amplitude; The risk level is yellow if at least one of the following conditions is met: lie in – between, Located between 0.1 and 0.2, 0. as well as ; If both the first and second conditions are met, the risk level is orange. Meeting the first condition means that the following conditions must be met: lie in – as well as At least one value between 0.05 and 0.1; satisfying the second condition means that it needs to meet the following: and At least one of them; The risk level is red if at least one of the following conditions is met. The specific conditions are as follows: Less than , Less than 0.05 as well as .

[0073] The above thresholds for risk levels can be set as needed, such as... The thresholds (0.20, 0.10, 0.05) correspond to - Coordinates of the points on the stability boundary diagram The dimensionless distance of the stable boundary line.

[0074] It should be noted that when , All meet the corresponding conditions, from , The most severe risk level among the satisfied conditions is determined as the final risk level. For example, lie in – It belongs to the yellow risk level. A reading between 0.1 and 0.2 also falls under the yellow risk level. It belongs to the red risk level. If the risk level is the most severe, then red will be used as the final risk level. Furthermore, the mechanical integrity dimension is... Comparison between and The more severe case will be used as the standard in the comparison. In more severe cases, the focus is on the risk of stray bullet instability. In more severe cases, the focus is on the risk of fatigue damage.

[0075] In this embodiment, the risk level of the steam generator is accurately determined based on the reduced velocity, vibration amplitude, heat transfer deterioration safety margin, and shortest distance of the steam generator.

[0076] Figure 3 A flowchart of a steam generator monitoring method provided in this application embodiment. Figure 3 ,based on Figure 1 or Figure 2 In the embodiment shown, after step S101, the method further includes: Step S301: Determine the heat exchange efficiency of the steam generator based on real-time parameters.

[0077] In this embodiment, the device determines the heat exchange efficiency of the steam generator based on real-time parameters.

[0078] In one example, the device acquires real-time parameters of the steam generator, including: Lead-bismuth side: Inlet temperature outlet temperature ,flow

[0079] Water side: Inlet temperature outlet temperature Water supply flow rate ,pressure

[0080] Key point wall temperature (Limited measurement points). The heat transfer efficiency is: .

[0081] In another example, multiple simulation parameters of the steam generator under operating conditions are obtained based on the simulation model, and the heat exchange efficiency of the steam generator is determined based on these simulation parameters. For example, after constructing the simulation model, the steam generator is simulated under various operating conditions to obtain simulation parameters, which are then stored in a database. The specific simulation parameters are shown in Table-2. Table 2:

[0082] It should be noted that the simulation parameters mentioned above are merely examples; other unlisted simulation parameters, such as outlet temperature, also exist. Furthermore, the simulation parameters are associated with operating conditions. When heat exchange efficiency needs to be calculated, the simulation parameters associated with the current operating condition of the steam generator are retrieved from the database and used as the simulation parameters for the steam generator under its current operating state. Simulation parameters also participate in other calculations, as detailed in the calculation formulas within this application.

[0083] Step S302: Based on the heat exchange efficiency and the pressure drop parameters collected by the steam generator, determine the performance degradation parameters of the steam generator, and output the performance prompt information of the steam generator according to the performance degradation parameters.

[0084] After obtaining the heat exchange efficiency, the performance degradation parameters of the steam generator are determined based on the heat exchange efficiency and the pressure drop parameters collected by the steam generator. Based on the performance degradation parameters, the performance prompt information of the steam generator is output.

[0085] For example, pressure drop parameters The pressure signal at the inlet is determined by the sensors located at the inlet and outlet flanges of the steam generator.

[0086] The device constructs a feature vector based on performance degradation parameters and pressure drop parameters. If the deviation of the feature vector from the reference vector exceeds a threshold, a performance warning message indicating a risk of scaling or blockage in the steam generator is output. Furthermore, the feature vector can also be constructed based on performance degradation parameters, pressure drop parameters, measured flow rate of the steam generator, and temperature data.

[0087] In this embodiment, after constructing a simulation model, the device evaluates the performance degradation of the steam generator, thereby outputting accurate performance warning information.

[0088] Figure 4 A flowchart of a steam generator monitoring method provided in this application embodiment. Figure 4 .based on Figures 1 to 3 In any of the embodiments shown, after step S102, the method further includes: Step S401: Determine the temperature fluctuation parameters based on the wall temperature distribution parameters, and determine the first change parameter of thermal strain based on the temperature fluctuation parameters.

[0089] In this embodiment, after obtaining the wall temperature distribution parameters, the device can dynamically predict the remaining life of the steam generator. Specifically, the device determines temperature fluctuation parameters based on the wall temperature distribution parameters, that is, it extracts the temperature fluctuation sequence of key sections (such as the highest wall temperature point) from the wall temperature distribution parameters. As a load spectrum (temperature fluctuation parameter).

[0090] After obtaining the temperature fluctuation parameters, the thermal strain variation parameters are determined based on the temperature fluctuation parameters, and these variation parameters are defined as the first variation parameter.

[0091] In one example, the first fluctuation parameter is determined by the temperature fluctuation parameter, and the first change parameter is: ;in, For pipe materials at average temperature The coefficient of linear expansion.

[0092] In another example, the device determines the initial change parameter of thermal strain based on the temperature fluctuation parameter, which is the initial change parameter. The device then corrects the initial variation parameters based on the multi-axis constraint relationship of the feature tube to obtain the first temperature variation parameter. For example, the first temperature variation parameter is: , It is Poisson's ratio.

[0093] Step S402: Determine the second variation parameter of mechanical strain based on the vibration amplitude of the steam generator.

[0094] The device determines the variation parameter of mechanical strain based on the vibration amplitude of the steam generator. This variation parameter is defined as the second variation parameter, which is: ； in, The second variable parameter, Support span for the tube bundle; , These are geometric coefficients related to pipe end constraints and mode shapes; This represents the vibration amplitude.

[0095] Step S403: Determine the total change parameter based on the first change parameter and the second change parameter, and determine the remaining service life of the steam generator based on the total change parameter.

[0096] After determining the first and second change parameters, the total change parameter is determined based on the first and second change parameters. The total change parameter is, for example, [example parameter]. .

[0097] After determining the total variation parameters, the device determines the remaining service life of the steam generator based on these parameters. For example, the total variation parameter is the total strain amplitude. , for: ;in, The fatigue strength coefficient, The fatigue ductility coefficient, , For material index, For average stress, The elastic modulus. The device then... Replace with or Thus, iterative solutions are obtained. This refers to the total number of cycles that a characteristic tube can withstand from no damage to fatigue failure.

[0098] The device obtains the temperature fluctuation cycle i under the above method. This allows us to calculate the loss generated in each temperature fluctuation cycle i. To perform linear accumulation, i.e. ,when The time is determined as the end of life, that is, based on Determine the remaining useful life, i.e., 1- Then, multiply by the maximum service life to get the remaining service life.

[0099] Step S404: Based on the remaining service life, output maintenance recommendations for the steam generator.

[0100] After determining the remaining service life, output maintenance recommendations for the steam generator.

[0101] In one example, when the remaining service life is less than the preset service life, the warning message warns that heat transfer deterioration occurs in the Z region of the eddy current of the steam generator. For example, if the remaining service life is 30 days, the maintenance recommendation message is: "The remaining service life of the steam generator is 30 days. It is recommended to check the eddy current of the steam generator as soon as possible, and pay special attention to the Z region of the eddy current."

[0102] In another example, if the remaining service life is greater than or equal to the preset service life, and the warning message indicates that the heat transfer deterioration margin is less than the set value, then the maintenance suggestion message is: "The current heat transfer deterioration margin is low, and it is recommended to increase the feedwater flow rate by X%"; if the warning message indicates that the steam generator will enter the unstable operating zone after running N cycles, then the maintenance suggestion message is: "It is estimated that after XX hours (XX hours is calculated from the steam generator running N cycles), the Nth cycle will enter the unstable operating zone. Please prepare for load adjustment in advance." Unstable operating regions can be determined using stability boundary diagrams. For example, when... Furthermore, heat transfer deteriorates the safety margin. This represents the stable operating region in the stability boundary diagram. When exists and The stability boundary diagram contains a density wave instability region, which is the unstable operating region; when The stability boundary diagram shows a region dominated by heat transfer deterioration.

[0103] It should be noted that the warning information may also include the type of deterioration of the steam generator under heat transfer degradation. The types of heat transfer degradation include, but are not limited to, the first type of degradation and the second type of degradation. The first type of degradation is a sudden change in physical properties, and the second type of degradation may be caused by the buoyancy force or thermal acceleration of the steam generator.

[0104] when ( The pseudocritical temperature. °C, °C) and wall temperature gradient When this occurs, it is classified as Type I deterioration. Type I deterioration is characterized by the wall temperature peak appearing near the quasi-critical region, determined by specific heat capacity. The sharp drop in thermal conductivity The mutations are caused by a combination of factors.

[0105] When buoyancy parameters or thermal acceleration parameters When this occurs, it is classified as Type II deterioration. Type II deterioration is characterized by a wall temperature surge occurring far from the quasi-critical region, caused by turbulent quenching resulting from near-wall velocity profile distortion. Among these, The mainstream Grashof number; The mainstream Reynolds number; The dominant Prandtl number is q, where q is the local heat flux density at the wall. Mainstream fluid dynamic viscosity; ; The coefficient of thermal expansion of the fluid at constant pressure; This represents the increase in enthalpy of the fluid along the flow direction. The specific heat capacity at constant pressure of the fluid is used. In this embodiment, the device accurately predicts the remaining service life of the steam generator based on the strain parameters of the steam generator.

[0106] Figure 5 A flowchart of a steam generator monitoring method provided in this application embodiment. Figure 5 .based on Figures 1 to 4 In any of the embodiments shown, step S101 includes: Step S501: Construct the first spatial model corresponding to the feature tube based on the attribute parameters and thermal-hydraulic parameters of the feature tube in the steam generator.

[0107] In this embodiment, the attribute parameters and thermal-hydraulic parameters of the feature tube in the steam generator of the device are used to construct a first spatial model corresponding to the feature tube. The first spatial model is the three-dimensional spatial model of the feature tube.

[0108] Furthermore, when constructing the first spatial model, the characteristic tube is divided into N control volumes (typically N = 100–500) along its length. Mass, energy, and momentum balance equations are independently established for each control volume. The number of control volumes is determined through an irrelevance test: calculations are performed with N (odd) and 2N (even) control volumes. If the deviation of the key outputs (outlet steam temperature, total heat exchange) is less than 0.5%, the number of control volumes is considered sufficient; that is, the first spatial model consists of multiple control volumes.

[0109] For each control volume, a corresponding conservation relationship needs to be constructed. The conservation relationships include: Conservation of mass (steady state): This refers to the conservation of flow rate and mass at the outlet and inlet ends of the characteristic tube; Energy conservation (primary loop side:) ;in, The specific heat capacity at constant pressure of the fluid; To control the total mass of fluid within the volume; To control the transient partial derivative of the average temperature within the volume with respect to time; Control the mass flow rate within the volume; Specific enthalpy of the fluid at the inlet cross-section; Specific enthalpy of the fluid at the outlet section; The wall heat flux density; The total heat exchange area of ​​the tube wall is used to control the volume.

[0110] Energy conservation (secondary loop side): ; Heat conduction through the tube wall (one-dimensional radial): ; Pressure drop: ; respectively correspond to frictional pressure drop Accelerate pressure drop and gravitational pressure drop .

[0111] Step S502: Based on the phase change process of the liquid in the feature tube in the flow direction, the first spatial model is divided into multiple flow regions, and based on the characteristics of the liquid in the feature tube in the flow regions, the first correlation between heat transfer and pressure drop in the flow regions is constructed to obtain the second spatial model.

[0112] In this embodiment, the working fluid on the secondary loop side inside the feature tube undergoes a complete phase change process along the flow direction, so it is necessary to divide the first spatial model into multiple flow regions based on the phase change process.

[0113] For example, the flow regions include: a subcooled region, a saturated nucleated boiling region, a post-evaporation region, and a superheated steam region. See Table 3 for details of each flow region. Table 3:

[0114] Based on the characteristics of the liquid in the flow region within the characteristic tube, the device constructs a first correlation between heat transfer and pressure drop in the flow region, thus obtaining a second spatial model.

[0115] For example, the working fluid on the secondary loop side inside the tube undergoes a complete phase change process, and different heat transfer correlations are used in different flow regions. In the geometry of a helical tube, the secondary flow induced by centrifugal force has an enhancing effect on heat transfer, as demonstrated by the Dean number. Characterizing the intensity of the secondary flow: .

[0116] The primary correlations between the various flow regions are as follows: Subcooled liquid zone (single phase): ; Saturated nucleate boiling region (two phases): A superimposed correlation equation is adopted, comprehensively considering the contributions of nucleate boiling and two-phase forced convection: ;in, For two-phase macroscopic convection components, For the nucleus boiling microscopic component, It is a superposition function; Post-evaporation zone: After evaporation, the wall surface is in direct contact with steam, resulting in a significant decrease in the heat transfer coefficient and a higher steam content at the drying point. Determined by empirical correlation: The first association of the region after evaporation is: ,in, For the two-phase mixed Reynolds number, Steam content; Superheated steam zone (single phase): Employs a spiral tube heat exchanger connection for single-phase steam (similar in form to the subcooled liquid zone, with physical properties based on steam values): .

[0117] Step S503: Based on the material properties of the feature tube and the flow characteristics of the liquid outside the feature tube, construct the second correlation relationship of the heat transfer outside the tube in the second spatial model to obtain the third spatial model.

[0118] In addition, the device also needs to construct a second correlation relationship for heat transfer outside the tube in the second spatial model based on the material properties of the feature tube and the liquid flow characteristics outside the feature tube, thus forming a third spatial model.

[0119] For example, liquid metals have extremely low Prandtl numbers, and their heat transfer mechanism, dominated by thermal diffusion, differs significantly from that of conventional high-Pr fluids. Therefore, a second correlation exists regarding heat transfer in the helical tube bundle (outside the tube) via lateral scouring on the outer side (shell side): in, The functional form is related to the flow state and the tube bundle geometry. The Prandtl number at the wall temperature. It is the tube bundle's section diameter ratio (the ratio of the center distance between adjacent tubes to the outer diameter of the tube).

[0120] Furthermore, the overall heat transfer coefficient must be determined based on the second and first correlation relationships. That is, based on the heat transfer coefficients on both the inside and outside of the tube, and considering the thermal resistance of the tube wall and the fouling resistance, the overall heat transfer coefficient is determined. : ;in, Reference diameter (usually the inner diameter) (or average diameter). The thermal conductivity of the pipe (as it varies with temperature). For fouling thermal resistance; the thermal conductivity of pipes has a linear relationship with temperature, and the formula for typical pipes is: Applicable temperature Range 20–400°C.

[0121] In addition, pressure drop calculations are required. Frictional pressure drop. In helical tubes, a helical correction factor needs to be introduced to reflect the enhancing effect of curvature on flow resistance. The relationship between the friction coefficients of helical tubes and straight tubes in the single-phase region can be expressed as a general functional form: ;in, The friction coefficient correction function for the helical tube depends on the flow state and curvature ratio. The frictional pressure drop in the two-phase region is calculated by multiplying the homogeneous flow model by a two-phase multiplication factor. calculate: ;in, It is a two-phase multiplication factor. This refers to the steam content.

[0122] Step S504: Iteratively solve the first and second correlation relationships of the third space model to obtain the simulation model.

[0123] After obtaining the third spatial model, the simulation model is obtained through iterative solution based on the first and second correlation relationships.

[0124] Specifically, the heat exchange between the outside and inside of the tube is achieved through the coupling of thermal boundary conditions via the solid tube wall. The device operates along the length of the characteristic tube. The heat transfer and thermal balance between the outside and inside of the control volume are calculated, that is, based on the first and second correlation relationships, the heat transfer and thermal balance between the outside and inside of the control volume are calculated, thereby realizing the iterative solution of the boundary conditions in the third space model. The iterative solution process is as follows: 1. Characteristic tube parameter and operating condition initialization: Define the geometric parameters of the characteristic tube according to the design drawings ( , , , , , ), set running boundary conditions ( , , , ), perform physical property initialization; 2. Initial wall temperature assumption: Assume the initial wall temperature distribution. Typically, a linear interpolation of the inlet fluid temperature and the outlet fluid temperature is taken; to improve the convergence speed, the convergence solution of the previous neighboring operating condition can be taken as the initial field. 3. Flow Zone Determination and Heat Transfer Coefficient Calculation: Based on the local working fluid conditions (temperature, vapor content, pressure), determine the flow zone (subcooled liquid zone, nucleus boiling zone, post-evaporation zone, superheated steam zone) to which the current control volume belongs, and select the corresponding heat transfer correlation formula for calculation. and ; 4. Update heat flux density and wall temperature: Update the heat flux density distribution based on the continuous interfacial thermal equilibrium conditions. The wall temperature is updated by solving the heat conduction equation of the pipe wall. When the calculated heat flux deviation between the two sides exceeds the allowable range, a sub-relaxation factor is introduced. To suppress iterative oscillations; 5. Convergence Criteria and Full-Field Verification: Convergence Criteria for Calculating Wall Temperature ,Pick ×K; if satisfied, the iteration converges and the entire data is output; otherwise, return to step 3, let Continue iterating; each iteration along Each control volume is scanned sequentially, requiring 15–40 external iterations under typical operating conditions to achieve global convergence; pressure drop It is obtained by integrating the flow pattern and physical properties of each control volume after convergence.

[0125] The simulation model obtained above can be used for batch simulation calculations across all operating conditions, constructing a parameterized simulation result database covering the entire operating range of the equipment. This database provides crucial data support for subsequent steps, and its specific uses include: Support model reduction processing: The calculation results of the lumped parameter model under different operating conditions (different loads, different inlet conditions) are aggregated into a high-dimensional data matrix, which serves as a sample dataset for intrinsic orthogonal decomposition or artificial neural network training. Through reduction processing, the input-output mapping relationship of the simulation model is compressed into a low-dimensional surrogate model, enabling real-time computing capabilities.

[0126] Supporting fault feature identification: Extracting feature parameter sequences corresponding to various failure mechanisms (such as wall temperature gradient distribution) Heat transfer deterioration safety margin (etc.), establish a mapping relationship of "operating condition parameters → characteristic parameters → failure type". Supporting the construction of digital twins: storing wall temperature distribution across the entire operating range Heat flux density distribution Pressure drop Heat exchange efficiency Key outputs, such as these, serve as a standard reference database for training offline models (the model after order reduction) and comparing them online.

[0127] Corresponding to the above-described method for monitoring steam generators, this application also provides a monitoring device for steam generators. Figure 6 This is a schematic diagram of a monitoring device for a steam generator provided in an embodiment of this application. The monitoring device 600 for a steam generator provided in this embodiment includes: Module 610 is used to construct a simulation model of the steam generator based on the property parameters of the characteristic tubes and the thermal-hydraulic parameters in the steam generator. The input module 620 is used to input the real-time parameters collected by the steam generator into the simulation model for simulation, and to obtain the wall temperature distribution parameters, heat flux density distribution parameters and the coordinate points of the current operating condition of the steam generator on the stability boundary diagram. The first determining module 630 is used to determine the heat transfer deterioration safety margin of the characteristic tube based on the wall temperature distribution parameters when the steam generator is determined to be in a state of heat transfer deterioration based on the wall temperature distribution parameters, and to determine the shortest distance between the coordinate point and the stability boundary line. The second determining module 640 is used to determine the target confidence level based on the heat flux density distribution parameters, and to determine the risk level of the steam generator based on the heat transfer deterioration safety margin and the shortest distance, and to output the early warning information of the steam generator based on the risk level and the target confidence level.

[0128] In some implementations, the monitoring device 600 of the steam generator is also used for: Based on real-time parameters, determine the reduced velocity and vibration amplitude of the steam generator; The risk level of the steam generator is determined based on the reduction velocity, vibration amplitude, heat transfer deterioration safety margin, and shortest distance.

[0129] In some implementations, the monitoring device 600 of the steam generator is also used for: Based on the property parameters of the characteristic tubes and the thermal-hydraulic parameters in the steam generator, construct the spatial model corresponding to the steam generator; The spatial model is reduced in order to obtain the simulation model.

[0130] In some implementations, the monitoring device 600 of the steam generator is also used for: The critical heat flux density parameters of the steam generator are obtained based on the critical heat flux density model. The heat flux margin is determined based on the critical heat flux density parameter and the heat flux density distribution parameter. The target confidence level is determined based on the heat flux density margin.

[0131] In some implementations, the monitoring device 600 of the steam generator is also used for: The heat exchange efficiency of the steam generator is determined based on real-time parameters. Based on the heat exchange efficiency and the pressure drop parameters collected by the steam generator, the performance degradation parameters of the steam generator are determined, and the performance warning information of the steam generator is output according to the performance degradation parameters.

[0132] In some implementations, the monitoring device 600 of the steam generator is also used for: Based on the simulation model, the steam generator is simulated to obtain multiple simulation parameters of the steam generator in the operating state; The heat exchange efficiency of the steam generator is determined based on various simulation parameters and real-time parameters.

[0133] In some implementations, the monitoring device 600 of the steam generator is also used for: Based on the wall temperature distribution parameters, the temperature fluctuation parameters are determined, and based on the temperature fluctuation parameters, the first change parameter of thermal strain is determined. The second variation parameter of mechanical strain is determined based on the vibration amplitude of the steam generator; Based on the first and second changing parameters, the total changing parameters are determined, and the remaining service life of the steam generator is determined based on the total changing parameters. Based on the remaining service life, provide maintenance recommendations for the steam generator.

[0134] In some implementations, the monitoring device 600 of the steam generator is also used for: The initial variation parameters of thermal strain are determined based on the temperature fluctuation parameters; Based on the multi-axis constraint relationship of the feature tube, the initial variation parameters are corrected to obtain the first variation parameters.

[0135] In some implementations, the monitoring device 600 of the steam generator is also used for: Based on the property parameters and thermo-hydraulic parameters of the characteristic tubes in the steam generator, a first spatial model corresponding to the characteristic tubes is constructed. Based on the phase change process of the liquid in the characteristic tube in the flow direction, the first spatial model is divided into multiple flow regions. Based on the characteristics of the liquid in the characteristic tube in the flow region, the first correlation between heat transfer and pressure drop in the flow region is constructed to obtain the second spatial model. Based on the material properties of the feature tube and the flow characteristics of the liquid outside the feature tube, a second correlation relationship for heat transfer outside the tube in the second spatial model is constructed, resulting in a third spatial model. The simulation model is obtained by iteratively solving the first and second correlation relationships of the third space model.

[0136] The steam generator monitoring device and the steam generator monitoring method provided in the above embodiments of this application belong to the same application concept and can execute the steam generator monitoring method provided in any of the above embodiments of this application. They possess the corresponding functional modules and beneficial effects for executing the steam generator monitoring method. Technical details not described in detail in this embodiment can be found in the specific processing content of the steam generator monitoring method provided in the above embodiments of this application, and will not be repeated here.

[0137] The functions of each module in the monitoring device of the steam generator can be implemented by the same or different processors, and this application embodiment does not limit this.

[0138] It should be understood that the modules in the monitoring device of the steam generator described above can be implemented by a processor calling firmware. For example, the system includes a processor connected to a memory containing instructions. The processor calls the instructions stored in the memory to implement any of the above methods or to realize the functions of each module of the device. The processor can be a general-purpose processor, such as a CPU or microprocessor, and the memory can be internal to the device or external to the system. Alternatively, the modules in the system can be implemented as hardware circuits. By designing the hardware circuits, some or all of the module functions can be realized. The hardware circuit can be understood as one or more processors. For example, in one implementation, the hardware circuit is an ASIC, and the functions of some or all of the above modules are realized by designing the logical relationships between the components within the circuit. In another implementation, the hardware circuit can be implemented by a PLD, such as an FPGA, which can include a large number of logic gates. The connection relationships between the logic gates are configured through a configuration file, thereby realizing the functions of some or all of the above modules. All modules of the monitoring device of the steam generator described above can be implemented entirely by a processor calling firmware, entirely by hardware circuits, or partially by a processor calling firmware with the remaining parts implemented by hardware circuits.

[0139] In this application embodiment, a processor is a circuit with signal processing capabilities. In one implementation, the processor can be a circuit with instruction reading and execution capabilities, such as a CPU, microprocessor, GPU, or DSP. In another implementation, the processor can implement certain functions through the logical relationships of hardware circuits. These logical relationships are fixed or reconfigurable. For example, the processor may be a hardware circuit implemented as an ASIC or PLD, such as an FPGA. In a reconfigurable hardware circuit, the process of the processor loading a configuration document and configuring the hardware circuit can be understood as the processor loading instructions to implement the functions of some or all of the above modules. Furthermore, it can also be a hardware circuit designed for artificial intelligence, which can be understood as an ASIC, such as an NPU, TPU, or DPU.

[0140] As can be seen, each module in the monitoring device of the steam generator described above can be one or more processors (or processing circuits) configured to implement the above methods, such as: CPU, GPU, NPU, TPU, DPU, microprocessor, DSP, ASIC, FPGA, or a combination of at least two of these processor types.

[0141] Furthermore, the modules in the monitoring device of the steam generator described above can be integrated in whole or in part, or they can be implemented independently. In one implementation, these modules are integrated together and implemented in the form of a System-on-Chip (SoC). The SoC may include at least one processor for implementing any of the above methods or implementing the functions of the modules of the device. The at least one processor can be of different types, such as CPU and FPGA, CPU and artificial intelligence processor, CPU and GPU, etc.

[0142] This application provides a schematic diagram of the structure of an electronic device, see [link]. Figure 7 As shown, the electronic device includes a memory 700 and a processor 710; wherein the memory 700 is connected to the processor 710 and is used to store programs; the processor 710 is used to implement the steam generator monitoring method disclosed in any of the above embodiments by running the programs stored in the memory 700.

[0143] Specifically, the aforementioned electronic device may further include: a bus, a communication interface 720, an input device 730, and an output device 740. The electronic device may also include a data transceiver module, an image monitoring module, and a signal monitoring module.

[0144] The processor 710, memory 700, communication interface 720, input device 730, and output device 740 are interconnected via a bus. Among them: A bus can include a pathway for transmitting information between various components in an electronic device.

[0145] The processor 710 can be a general-purpose processor, such as a general-purpose central processing unit (CPU), a microprocessor, etc., or an application-specific integrated circuit (ASIC), or one or more integrated circuits used to control the execution of the program of the present invention. It can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an off-the-shelf programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0146] The processor 710 may include a main processor, as well as a baseband chip, modem, etc.

[0147] The memory 700 stores a program that executes the technical solution of this invention, and may also store an operating system and other key business functions. Specifically, the program may include program code, which includes computer operation instructions. More specifically, the memory 700 may include read-only memory (ROM), other types of static storage devices capable of storing static information and instructions, random access memory (RAM), other types of dynamic storage devices capable of storing information and instructions, disk storage, flash memory, etc.

[0148] Input device 730 may include a device for receiving data and information input by a user, such as a keyboard, mouse, camera, scanner, light pen, voice input device, touch screen, pedometer, or gravity sensor.

[0149] Output device 740 may include devices that allow information to be output to a user, such as a display screen, printer, speaker, etc.

[0150] The communication interface 720 may include a device that uses any transceiver to communicate with other devices or communication networks, such as Ethernet, Radio Access Network (RAN), Wireless Local Area Network (WLAN), etc.

[0151] The processor 710 executes the program stored in the memory 700 and calls other devices, which can be used to implement the various steps of any of the steam generator monitoring methods provided in the above embodiments of this application.

[0152] It should be noted that electronic devices can be in-vehicle terminals, mobile phones, wearable devices, or servers, etc.; or, they can include electronic devices such as in-vehicle terminals.

[0153] This application also proposes a chip, which includes a processor and a data interface. The processor reads and runs a program stored in the memory through the data interface to execute the steam generator monitoring method described in any of the above embodiments. For the specific processing procedure and its beneficial effects, please refer to the embodiments of the steam generator monitoring method described above.

[0154] In addition to the methods and devices described above, embodiments of this application may also be computer program products, which include computer program instructions that, when executed by a processor, cause the processor to perform the steps in the monitoring methods for steam generators according to various embodiments of this application as described in any of the foregoing embodiments of this specification.

[0155] Computer program products can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of this application. The programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the power device, as a standalone firmware package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0156] Furthermore, embodiments of this application may also be storage media storing computer programs, which are executed by a processor in the steps of the monitoring method for a steam generator according to various embodiments of this application described in any of the above embodiments of this specification, specifically implementing the steps of the monitoring method for the steam generator as described above.

[0157] For the foregoing method embodiments, in order to simplify the description, they are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, because according to this application, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0158] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For apparatus embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0159] The steps in the methods of the various embodiments of this application can be adjusted, merged, or deleted in order according to actual needs, and the technical features described in each embodiment can be replaced or combined.

[0160] The units of the apparatus in the various embodiments of this application can be merged, divided, and deleted according to actual needs.

[0161] It should be understood that the disclosed terminals, devices, and methods can be implemented in other ways, given the several embodiments provided in this application. For example, the terminal embodiments described above are merely illustrative. For instance, the division of modules or sub-modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple sub-modules or modules may be combined or integrated into another module, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or modules, and may be electrical, mechanical, or other forms.

[0162] The modules or submodules described as separate components may or may not be physically separate. The components that constitute a module or submodule may or may not be physical modules or submodules; that is, they may be located in one place or distributed across multiple network modules or submodules. Some or all of the modules or submodules can be selected to achieve the purpose of this embodiment's solution, depending on actual needs.

[0163] Furthermore, the functional modules or sub-modules in the various embodiments of this application can be integrated into one processing module, or each module or sub-module can exist physically separately, or two or more modules or sub-modules can be integrated into one module. The integrated modules or sub-modules described above can be implemented in hardware or as firmware functional modules or sub-modules.

[0164] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer firmware, or a combination of both. To clearly illustrate the interchangeability of hardware and firmware, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or firmware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0165] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly using hardware, firmware units executed by a processor, or a combination of both. The firmware unit can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0166] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0167] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A monitoring method for a steam generator, characterized in that, include: Based on the property parameters of the characteristic tubes in the steam generator and the thermal-hydraulic parameters, a simulation model corresponding to the steam generator is constructed. The real-time parameters collected by the steam generator are input into the simulation model for simulation, and the wall temperature distribution parameters, heat flux density distribution parameters, and coordinates of the current operating condition of the steam generator on the stability boundary diagram are obtained. If the steam generator is determined to be in a state of heat transfer deterioration based on the wall temperature distribution parameters, the heat transfer deterioration safety margin of the characteristic tube is determined based on the wall temperature distribution parameters, and the shortest distance between the coordinate point and the stability boundary line is determined. The target confidence level is determined based on the heat flux density distribution parameters, and the risk level of the steam generator is determined based on the heat transfer deterioration safety margin and the shortest distance. The warning information of the steam generator is output based on the risk level and the target confidence level.

2. The monitoring method for a steam generator according to claim 1, characterized in that, Determining the risk level of the steam generator based on the heat transfer deterioration safety margin and the shortest distance includes: Based on the real-time parameters, the reduced velocity and vibration amplitude of the steam generator are determined; The risk level of the steam generator is determined based on the reduction rate, the vibration amplitude, the heat transfer deterioration safety margin, and the shortest distance.

3. The monitoring method for a steam generator according to claim 1, characterized in that, The step of constructing a simulation model of the steam generator based on the property parameters of the characteristic tubes and the thermo-hydraulic parameters in the steam generator includes: Based on the property parameters of the characteristic tubes and the thermal-hydraulic parameters in the steam generator, construct the spatial model corresponding to the steam generator; The spatial model is reduced in order to obtain the simulation model.

4. The monitoring method for a steam generator according to claim 1, characterized in that, Determining the target confidence level based on the heat flux density distribution parameters includes: The critical heat flux density parameters of the steam generator are obtained based on the critical heat flux density model. The heat flux margin is determined based on the critical heat flux density parameter and the heat flux density distribution parameter. The target confidence level is determined based on the heat flux density margin.

5. The monitoring method for a steam generator according to claim 1, characterized in that, Also includes: The heat exchange efficiency of the steam generator is determined based on the real-time parameters. Based on the heat exchange efficiency and the pressure drop parameters collected by the steam generator, the performance degradation parameters of the steam generator are determined, and the performance prompt information of the steam generator is output according to the performance degradation parameters.

6. The monitoring method for a steam generator according to claim 5, characterized in that, Determining the heat exchange efficiency of the steam generator based on the real-time parameters includes: Based on the simulation model, the steam generator is simulated to obtain multiple simulation parameters of the steam generator in its operating state; The heat exchange efficiency of the steam generator is determined based on the simulation parameters and real-time parameters.

7. The monitoring method for a steam generator according to claim 1, characterized in that, After inputting the real-time parameters collected by the steam generator into the simulation model for simulation, the method further includes: Based on the wall temperature distribution parameters, the temperature fluctuation parameters are determined, and based on the temperature fluctuation parameters, the first change parameter of thermal strain is determined; The second variation parameter of mechanical strain is determined based on the vibration amplitude of the steam generator; Based on the first and second changing parameters, the total changing parameters are determined, and the remaining service life of the steam generator is determined based on the total changing parameters. Based on the remaining service life, output maintenance recommendations for the steam generator.

8. The monitoring method for a steam generator according to claim 7, characterized in that, The step of determining the first change parameter of thermal strain based on the temperature fluctuation parameter includes: The initial variation parameters of thermal strain are determined based on the temperature fluctuation parameters. Based on the multi-axis constraint relationship of the feature tube, the initial variation parameters are corrected to obtain the first variation parameters.

9. The monitoring method for a steam generator according to any one of claims 1-8, characterized in that, The step of constructing a simulation model of the steam generator based on the property parameters of the characteristic tubes and the thermo-hydraulic parameters in the steam generator includes: Based on the property parameters and thermal-hydraulic parameters of the characteristic tube in the steam generator, a first spatial model corresponding to the characteristic tube is constructed. Based on the phase change process of the liquid in the feature tube in the flow direction, the first spatial model is divided into multiple flow regions, and based on the characteristics of the liquid in the feature tube in the flow region, a first correlation between heat transfer and pressure drop in the flow region is constructed to obtain the second spatial model. Based on the material properties of the feature tube and the flow characteristics of the liquid outside the feature tube, a second correlation relationship for heat transfer outside the tube in the second spatial model is constructed to obtain a third spatial model. The simulation model is obtained by iteratively solving the first and second correlation relationships of the third spatial model.

10. A monitoring device for a steam generator, characterized in that, include: The construction module is used to construct a simulation model of the steam generator based on the property parameters of the characteristic tubes and the thermal-hydraulic parameters in the steam generator. The input module is used to input the real-time parameters collected by the steam generator into the simulation model for simulation, and to obtain the wall temperature distribution parameters, heat flux density distribution parameters and the coordinate points of the current operating condition of the steam generator on the stability boundary diagram. The first determining module is used to determine the heat transfer degradation safety margin of the characteristic tube based on the wall temperature distribution parameters when the steam generator is determined to be in a state of heat transfer degradation based on the wall temperature distribution parameters, and to determine the shortest distance between the coordinate point and the stability boundary line. The second determining module is used to determine the target confidence level based on the heat flux density distribution parameters, and to determine the risk level of the steam generator based on the heat transfer deterioration safety margin and the shortest distance, and to output the early warning information of the steam generator based on the risk level and the target confidence level.

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