Condensate holdup calculation method and apparatus for nuclear power plant, and storage medium and electronic device

Abstract

The present invention relates to a condensate holdup calculation method and apparatus for a nuclear power plant, and a storage medium and an electronic device. The method comprises: establishing a geometric condensate holdup analysis model for an object to be analyzed, and meshing the geometric model to obtain a three-dimensional mesh model; using a single-phase multi-component model to perform calculation on the three-dimensional mesh model, so as to obtain the flow fields and component distributions of a gas phase and a liquid phase in a phase change process; on the basis of the flow fields and component distributions of the gas phase and the liquid phase in the phase change process, performing calculation in combination with a control equation for said object on a condensation wall surface, so as to obtain the generation rate of condensate on the condensation wall surface; on the basis of the generation rate of condensate, calculating the distribution of a liquid film on the condensation wall surface; and on the basis of the distribution on the condensation wall surface, analyzing wall condensation patterns under different steam conditions by means of adjusting calculation conditions, so as to obtain condensate holdup data of the condensation wall surface. The present invention can quantitatively predict and evaluate the accumulation of condensate under different structures and operating conditions, thereby preventing damage to devices and the risks of accidents.

Description

Method and device for calculating condensate retention in nuclear power plant, storage medium and electronic equipment TECHNICAL FIELD

[0001] The present application relates to the technical field of nuclear power plant condensation heat transfer simulation, more particularly to a method and device for calculating condensate retention in nuclear power plant, a storage medium and an electronic equipment. BACKGROUND

[0002] Containment spray system is an important guarantee system of nuclear power plant. When the containment occurs in accident condition, the system can spray cooling medium to the containment to perform evaporation cooling, so as to control the pressure and temperature inside the containment within the permissible range.

[0003] The spray system needs to suck water from the pit in the recirculation spray stage. In order to ensure the safe operation of the containment spray pump, it is necessary to ensure that there is sufficient effective net positive suction head at the inlet of the pump. Therefore, it is necessary to ensure that the liquid level after the containment spray pump takes water meets the requirement of the minimum water storage amount of the containment spray pump, and the quantitative analysis of the water loss amount of the containment spray pump in accident condition is the key. The water loss amount mainly includes containment leakage water amount, containment return tolerance loss, containment retention water amount, etc. Since the retention water amount is affected by many factors such as water film thickness and pressure, it is difficult to calculate the wall / floor condensate. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a method and device for calculating condensate retention in nuclear power plant, a storage medium and an electronic equipment in view of the problems in the prior art.

[0005] The technical scheme adopted by the present application to solve the technical problem is that a method for calculating condensate retention in nuclear power plant is constructed, comprising the following steps:

[0006] A condensate retention analysis geometric model of an object to be analyzed is established, and the geometric model is meshed to obtain a three-dimensional mesh model;

[0007] A single-phase multi-component model is used to calculate the three-dimensional mesh model to obtain the flow field and component distribution of the gas-liquid two-phase in the phase change process;

[0008] Based on the flow field and component distribution of the gas-liquid two-phase in the phase change process, the control equation of the object to be analyzed on the condensation wall is combined to calculate the condensate generation rate on the condensation wall;

[0009] Based on the condensate generation rate, the distribution of the liquid film on the condensation wall is calculated;

[0010] According to the distribution of the condensation wall, the calculation conditions are adjusted to analyze the wall condensation law under different steam conditions, and the condensate retention data of the condensation wall are obtained.

[0011] In the nuclear power plant condensate retention amount calculation method, the condensate retention amount analysis geometric model of the to-be-analyzed object is established, and the geometric model is meshed to obtain a three-dimensional grid model, which comprises:

[0012] According to the structure shape and size of the to-be-analyzed object, a three-dimensional geometric model of the to-be-analyzed object is established;

[0013] According to the structure function and working condition of the to-be-analyzed object, the three-dimensional geometric model is simplified to obtain a simplified three-dimensional model;

[0014] The simplified three-dimensional model is meshed to obtain an initial grid model;

[0015] The initial grid model is processed to obtain the three-dimensional grid model.

[0016] In the nuclear power plant condensate retention amount calculation method, the initial grid model is processed to obtain the three-dimensional grid model, which comprises:

[0017] Extracting a fluid calculation domain required for calculation from the initial grid model;

[0018] Smooth and optimize the fluid calculation domain grid;

[0019] Determine the inlet condition, outlet condition and wall boundary condition of the fluid calculation domain grid, complete the meshing, and obtain the three-dimensional grid model.

[0020] In the nuclear power plant condensate retention amount calculation method, the three-dimensional grid model is calculated by using a single-phase multi-component model to obtain the flow field and component distribution of the gas-liquid two-phase in the phase change process, which comprises:

[0021] In the condensation process, a single-phase multi-component fluid is determined;

[0022] Determine whether the fluid reaches an equilibrium state;

[0023] If yes, the condensation transition of the vapor component in the gas phase to the liquid phase is completed through the coupling of the wall source term;

[0024] Based on the single-phase multi-component model, the mixed gas parameters of the three-dimensional grid model are calculated;

[0025] Performing iterative calculation, the flow field and component distribution of the gas-liquid two-phase in the phase change process are obtained.

[0026] In the nuclear power plant condensate retention amount calculation method, the calculation based on the flow field and the component distribution of the gas-liquid two-phase in the phase change process, combined with the control equation of the to-be-analyzed object on the condensing wall surface, obtains the condensate generation rate on the condensing wall surface, including:

[0027] Based on the flow field and the component distribution of the gas-liquid two-phase in the phase change process, the latent heat released by the steam at any time is calculated.

[0028] According to the control equation of the condensing wall surface, the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated.

[0029] The component loss of the mixed gas in the phase change process is calculated.

[0030] According to the mass source term, the energy source term, the momentum source term, and combined with the wall surface temperature, the updated phase change rate is calculated.

[0031] According to the updated phase change rate and the latent heat, the condensate generation rate on the wall surface unit at each time is obtained.

[0032] Iterative calculation is performed to obtain the condensate generation rate on the condensing wall surface at different times.

[0033] In the nuclear power plant condensate retention amount calculation method, the calculation based on the flow field and the component distribution of the gas-liquid two-phase in the phase change process, combined with the control equation of the to-be-analyzed object on the condensing wall surface, obtains the condensate generation rate on the condensing wall surface, including:

[0034] Based on the control equation of the condensing wall surface, the following calculations are performed:

[0035] According to the initial phase change rate, the mass transfer of the gas phase steam component to the liquid phase water component is calculated to obtain the mass source term;

[0036] According to the initial phase change rate and the latent heat of vaporization of the steam, the heat transferred from the gas phase to the liquid phase is calculated to obtain the energy source term;

[0037] According to the wall surface viscous stress and pressure, the momentum loss between gas and liquid is calculated to obtain the momentum source term.

[0038] In the nuclear power plant condensate retention amount calculation method, the calculation of the component loss of the mixed gas in the phase change process includes:

[0039] In the phase change process, according to the proportional loss of the gas phase steam component, the change of the component fraction of the mixed gas is calculated; the change of the component fraction of the mixed gas is the combined loss of the mixed gas.

[0040] In the nuclear power plant condensate retention amount calculation method, the calculation according to the mass source term, the energy source term, the momentum source term, and the wall surface temperature comprises:

[0041] The equilibrium pressure of steam during phase change is calculated according to the mass source term, the energy source term, the momentum source term, and the temperature of mixed gas;

[0042] The saturation vapor pressure at the gas-liquid interface is obtained by calculating according to the equilibrium pressure of steam during phase change and the wall surface temperature, and the updated phase change rate is obtained.

[0043] In the nuclear power plant condensate retention amount calculation method, the calculation of the distribution of the liquid film on the condensing wall surface based on the condensate generation rate comprises:

[0044] The distribution of the liquid film on the condensing wall surface is calculated based on the condensate generation rate by using a liquid film model.

[0045] In the nuclear power plant condensate retention amount calculation method, the calculation of the distribution of the liquid film on the condensing wall surface based on the condensate generation rate comprises:

[0046] A liquid film sub-grid is established in the first calculation unit of the wall surface;

[0047] The condensate generation rate is determined as the inlet velocity boundary condition of the liquid film sub-grid;

[0048] In the liquid film sub-grid, the flow and heat conduction of the liquid film are calculated to obtain the velocity, thickness, and temperature distribution of the liquid film;

[0049] The liquid-gas phase change rate is obtained by calculating the interfacial energy balance between the liquid film and the gas phase;

[0050] The average velocity of the liquid film is obtained, and the average velocity of the liquid film is determined as the outlet velocity boundary condition of the liquid film sub-grid;

[0051] The single-phase flow is calculated in the outer flow field;

[0052] The liquid film and gas phase flow coupling solution is obtained by iterative calculation of the inner and outer flow fields based on the velocity, thickness, and temperature distribution of the liquid film, and the single-phase flow; the liquid film and gas phase flow coupling solution is the distribution of the liquid film on the condensing wall surface.

[0053] In the nuclear power plant condensate retention amount calculation method, the calculation of the condensate retention amount data of the condensing wall surface according to the distribution of the condensing wall surface by adjusting the calculation conditions to analyze the wall surface condensation law under different steam conditions comprises:

[0054] determining parameters affecting condensation;

[0055] different values of the parameters affecting condensation are set respectively, and a plurality of groups of calculation conditions are obtained;

[0056] numerical simulation of condensate retention amount of each group of calculation conditions is performed according to the distribution of the condensing wall surface, variation law of wall condensation amount under different conditions is analyzed, and condensate retention amount data of the condensing wall surface are obtained.

[0057] The application further provides a nuclear power plant condensate retention amount calculation device, comprising:

[0058] a model construction unit, configured to establish a condensate retention amount analysis geometric model of an object to be analyzed, and perform grid division on the geometric model to obtain a three-dimensional grid model;

[0059] a phase change calculation unit, configured to calculate the three-dimensional grid model by using a single-phase multi-component model to obtain flow field and component distribution of gas-liquid two-phase in a phase change process;

[0060] a condensate generation rate calculation unit, configured to calculate condensate generation rate on the condensing wall surface based on the flow field and component distribution of the gas-liquid two-phase in the phase change process, and in combination with a control equation of the object to be analyzed on the condensing wall surface;

[0061] a liquid film distribution calculation unit, configured to calculate distribution of liquid film on the condensing wall surface based on the condensate generation rate;

[0062] a condensate retention amount calculation unit, configured to analyze wall condensation law under different steam conditions according to the distribution of the condensing wall surface by adjusting calculation conditions, and obtain condensate retention amount data of the condensing wall surface.

[0063] The application further provides a storage medium, which stores a computer program, and the computer program is suitable for being loaded by a processor to execute steps of the nuclear power plant condensate retention amount calculation method.

[0064] The application further provides an electronic device, which comprises a memory and a processor, the memory stores a computer program, and the processor executes steps of the nuclear power plant condensate retention amount calculation method by calling the computer program stored in the memory.

[0065] The nuclear power plant condensate retention amount calculation method, device, storage medium and electronic equipment provided by the present application have the following beneficial effects: a condensate retention amount analysis geometric model of an object to be analyzed is established, and the geometric model is meshed to obtain a three-dimensional mesh model; a single-phase multi-component model is used to calculate the three-dimensional mesh model to obtain the flow field and component distribution of the gas-liquid two-phase in the phase change process; based on the flow field and component distribution of the gas-liquid two-phase in the phase change process, the control equation of the object to be analyzed on the condensation wall surface is combined to calculate the condensate generation rate on the condensation wall surface; the distribution of the liquid film on the condensation wall surface is calculated based on the condensate generation rate; according to the distribution of the condensation wall surface, the wall condensation law under different steam conditions is analyzed by adjusting the calculation conditions, and the condensate retention amount data of the condensation wall surface are obtained. The present application can quantitatively predict and evaluate the condensate accumulation under different structures and working conditions, and avoid damage to the equipment and accident risks. BRIEF DESCRIPTION OF DRAWINGS

[0066] The present application will be further described below in combination with the drawings and examples, and the drawings are as follows:

[0067] Fig. 1 is a flowchart of the nuclear power plant condensate retention amount calculation method provided by the present application;

[0068] Fig. 2 is a principle block diagram of the nuclear power plant condensate retention amount calculation device provided by the present application;

[0069] Fig. 3 is a geometric model of a containment in an embodiment of the present application;

[0070] Fig. 4 is a simplified geometric model in an embodiment of the present application;

[0071] Fig. 5 is a meshing diagram of the simplified model in an embodiment of the present application;

[0072] Fig. 6 is a wall condensation parameter diagram in an embodiment of the present application;

[0073] Fig. 7 is a two-dimensional calculation domain and mesh diagram in an embodiment of the present application;

[0074] Fig. 8 is a wall condensation flux verification result in an embodiment of the present application;

[0075] Fig. 9 is a temperature distribution cloud chart in an embodiment of the present application;

[0076] Fig. 10 is a water vapor mass fraction cloud chart in an embodiment of the present application;

[0077] Fig. 11 is a dry air mass fraction cloud chart in an embodiment of the present application;

[0078] Fig. 12 is a velocity distribution cloud chart in an embodiment of the present application;

[0079] Figs. 13-16 are liquid film calculation results in an embodiment of the present application. Detailed Implementation

[0080] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0081] This invention constructs a geometric model of condensate retention and simplifies it according to the functions and working environment of each structure. Based on this geometric model, a numerical simulation model of condensate retention is established. This method enables detailed analysis of wall condensation patterns, providing guidance for the analysis of condensate retention in the object under analysis. The object under analysis can be a containment structure or other geometric structures, such as nozzles, auxiliary equipment, or nozzle mounting brackets.

[0082] Specifically, as shown in Figure 1, in a preferred embodiment, the method for calculating the condensate retention volume of the nuclear power plant includes the following steps:

[0083] Step S101: Establish a geometric model for analyzing the condensate retention of the object to be analyzed, and mesh the geometric model to obtain a three-dimensional mesh model.

[0084] Optionally, in some embodiments, establishing a geometric model for analyzing the condensate retention of the object to be analyzed, and meshing the geometric model to obtain a three-dimensional mesh model includes: establishing a three-dimensional geometric model of the object to be analyzed based on its structural shape and size; simplifying the three-dimensional geometric model based on the structural function and working conditions of the object to be analyzed to obtain a simplified three-dimensional model; meshing the simplified three-dimensional model to obtain an initial mesh model; and processing the initial mesh model to obtain a three-dimensional mesh model. The construction of the three-dimensional geometric model can be achieved using CAD software.

[0085] The process of processing the initial mesh model to obtain a three-dimensional mesh model includes: extracting the fluid computation domain required for calculation from the initial mesh model; smoothing and optimizing the fluid computation domain mesh; determining the inlet conditions, outlet conditions, and wall boundary conditions of the fluid computation domain mesh; completing the mesh generation; and obtaining a three-dimensional mesh model.

[0086] Step S102: Use a single-phase multi-component model to calculate the three-dimensional mesh model to obtain the flow field and component distribution of the gas-liquid two phases during the phase change process.

[0087] Optionally, in some embodiments, the single-phase multi-component model is used to calculate the three-dimensional grid model to obtain the flow field and component distribution of the gas-liquid two-phase in the phase change process, comprising: in the condensation process, determining the single-phase multi-component fluid; judging whether the fluid reaches an equilibrium state; if yes, completing the condensation transition of the vapor component in the gas phase to the liquid phase through the coupling of the wall source term; calculating the mixed gas parameters of the three-dimensional grid model based on the single-phase multi-component model; performing iterative calculation to obtain the flow field and component distribution of the gas-liquid two-phase in the phase change process.

[0088] Specifically, in the condensation process, the vapor-air mixed gas is regarded as a single-phase multi-component fluid. When each component in the gas phase reaches complete mixing, the single-phase multi-component fluid is in an equilibrium state. When the single-phase multi-component fluid is in the equilibrium state, the condensation transition of the vapor component in the gas phase to the liquid phase is realized through the coupling of the wall source term, and the mixed gas parameters (i.e. the density, specific heat capacity, viscosity, thermal conductivity, etc. of the mixed gas) are calculated. Finally, through iterative calculation, the flow field and component distribution of the gas-liquid two-phase in the phase change process are obtained. The source term is a generalized quantity, which represents the sum of all other terms in the unsteady term, the convection term and the diffusion term that cannot be included in the control equation. The addition of the source term is of great significance to the universality of the algorithm and the corresponding program discussed. If the source term is constant, it will not bring any difficulty in the establishment of the discrete equation. Generally, the source term is not constant, and is a function of the unknown quantity to be solved.

[0089] Step S103: based on the flow field and component distribution of the gas-liquid two-phase in the phase change process, the control equation of the condensation wall surface of the object to be analyzed is calculated to obtain the condensate production rate on the condensation wall surface.

[0090] Optionally, in some embodiments, based on the flow field and component distribution of the gas-liquid two-phase in the phase change process, the control equation of the condensation wall surface of the object to be analyzed is calculated to obtain the condensate production rate on the condensation wall surface, comprising: based on the flow field and component distribution of the gas-liquid two-phase in the phase change process, calculating the latent heat released by the vapor at any time; simulating the mass source term, energy source term and momentum source term of the mixed gas in the phase change process according to the control equation of the condensation wall surface; calculating the component loss of the mixed gas in the phase change process; calculating the updated phase change rate according to the mass source term, energy source term, momentum source term and wall temperature; calculating the condensate production rate on the wall surface unit at each time according to the updated phase change rate and the latent heat; performing iterative calculation to obtain the condensate production rate on the condensation wall surface at different times.

[0091] In some embodiments, simulating the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process according to the control equation of the condensation wall surface comprises: performing the following calculation based on the control equation of the condensation wall surface: calculating the mass transfer of the vapor component in the gas phase to the water component in the liquid phase according to the initial phase change rate to obtain the mass source term; calculating the heat transferred from the gas phase to the liquid phase according to the initial phase change rate and the latent heat of vaporization of the vapor to obtain the energy source term; and calculating the momentum loss between the gas and the liquid according to the viscous stress and the pressure of the wall surface to obtain the momentum source term.

[0092] In some embodiments, calculating the component loss of the mixed gas in the phase change process comprises: calculating the change of the component fraction of the mixed gas according to the proportional loss of the vapor component in the gas phase during the phase change process. The change of the component fraction of the mixed gas is the combined loss of the mixed gas.

[0093] According to the mass source term, the energy source term and the momentum source term, and in combination with the wall surface temperature, calculating the updated phase change rate comprises: calculating the equilibrium pressure of the vapor during the phase change according to the mass source term, the energy source term and the momentum source term and the temperature of the mixed gas; and calculating the saturation vapor pressure at the gas-liquid interface according to the equilibrium pressure of the vapor during the phase change in combination with the wall surface temperature to obtain the updated phase change rate.

[0094] After obtaining the condensate generation rate on the wall surface unit at each time, iterative calculation is performed to obtain the accumulation and distribution of the wall surface condensate at different times.

[0095] In the embodiments of the present application, the control equation is as follows:

[0096]

[0097]

[0098]

[0099]

[0100] The mass source term calculation method of the condensate is as follows:

[0101]

[0102] The mass source term calculation method of the vapor gas phase is as follows:

[0103]

[0104] The source term of the energy equation is as follows:

[0105]

[0106] is the density, for fluid velocity, for specific heat capacity, for fluid viscous force, for gravity acceleration, for thermal conductivity, for fluid pressure, D for mass diffusion coefficient, for component mass fraction, for latent heat of vaporization, V cell for grid cell volume, A face for cell wall area.

[0107] for momentum source term.

[0108] Step S104: calculating the distribution of the liquid film on the condensing wall surface based on the condensate production rate.

[0109] In some embodiments, calculating the distribution of the liquid film on the condensing wall surface based on the condensate production rate comprises: based on the condensate production rate, calculating the distribution of the liquid film on the condensing wall surface using a liquid film model.

[0110] In some embodiments, calculating the distribution of the liquid film on the condensing wall surface based on the condensate production rate comprises: establishing a liquid film sub-grid in a first calculation cell of the wall surface; determining the condensate production rate as an inlet velocity boundary condition of the liquid film sub-grid; in the liquid film sub-grid, calculating the flow and heat conduction of the liquid film to obtain the liquid film velocity, thickness and temperature distribution; calculating according to the interfacial energy balance between the liquid film and the gas phase to obtain the liquid-gas phase change rate; obtaining the average velocity of the liquid film and determining the average velocity of the liquid film as the outlet velocity boundary condition of the liquid film sub-grid; calculating the single-phase flow in the outer flow field; based on the liquid film velocity, thickness and temperature distribution, the single-phase flow, iteratively calculating the inner and outer flow fields to obtain the coupled solution of the liquid film and the gas phase flow; and the coupled solution of the liquid film and the gas phase flow is the distribution of the liquid film on the condensing wall surface. Here, the calculation cell is the divided grid, which includes nodes, interfaces and the like for calculation.

[0111] Specifically, a liquid film sub-grid is established in the first calculation unit near the wall surface for calculating heat transfer and flow of the liquid film; the condensate production rate obtained by the wall surface source term is used as the inlet velocity boundary condition of the liquid film sub-grid; in the liquid film sub-grid, the flow and heat conduction of the liquid film are calculated to obtain the liquid film velocity, thickness and temperature distribution; the liquid-gas phase change rate between the liquid film and the gas phase is calculated according to the interface energy balance to realize heat and mass exchange; then the average velocity of the liquid film is used as the outlet velocity boundary condition to realize the coupling with the outer flow field, and in the outer flow field, the liquid film is treated as air to perform single-phase flow calculation by using the Fluent software; finally, the coupling solution of the liquid film and the gas phase flow is obtained through iterative calculation of the inner and outer flow fields, that is, the distribution of the liquid film on the condensing wall.

[0112] Step S105: According to the distribution of the condensing wall, the calculation conditions are adjusted to analyze the wall condensation law under different steam conditions, and the condensate retention data of the condensing wall are obtained.

[0113] In some embodiments, according to the distribution of the condensing wall, the calculation conditions are adjusted to analyze the wall condensation law under different steam conditions, and the condensate retention data of the condensing wall are obtained, including: determining the parameters affecting condensation; setting different values of the parameters affecting condensation respectively to obtain multiple sets of calculation conditions; according to the distribution of the condensing wall, numerical simulation of the condensate retention of each set of calculation conditions is performed to analyze the change law of the wall condensation under different conditions, and the condensate retention data of the condensing wall are obtained. The parameters affecting condensation include, but are not limited to, inlet steam temperature, pressure, velocity and humidity, etc.

[0114] Referring to FIG. 2, FIG. 2 is a principle block diagram of a nuclear power plant condensate retention calculation device provided by the present application.

[0115] Specifically, as shown in FIG. 2, the nuclear power plant condensate retention calculation device includes:

[0116] The model construction unit 201 is configured to construct a condensate retention analysis geometric model of the object to be analyzed, and perform grid division on the geometric model to obtain a three-dimensional grid model.

[0117] The phase change calculation unit 202 is configured to calculate the three-dimensional grid model by using a single-phase multi-component model to obtain the flow field and component distribution of the gas-liquid two-phase in the phase change process.

[0118] The condensate production rate calculation unit 203 is configured to calculate the condensate production rate on the condensing wall based on the flow field and component distribution of the gas-liquid two-phase in the phase change process, in combination with the control equation of the object to be analyzed on the condensing wall.

[0119] The liquid film distribution calculation unit 204 is configured to calculate the distribution of the liquid film on the condensing wall surface based on the condensate generation rate.

[0120] The condensate retention amount calculation unit 205 is configured to obtain the condensate retention amount data of the condensing wall surface by adjusting the calculation conditions and analyzing the wall condensation law under different steam conditions according to the distribution of the condensing wall surface.

[0121] Specifically, the specific cooperation operation process between the units in the condensate retention amount calculation device for the nuclear power plant can refer to the above-mentioned condensate retention amount calculation method for the nuclear power plant, and will not be described here.

[0122] The present application can quantitatively predict and evaluate the condensate accumulation under different structures and working conditions, provide reference for structure design and process optimization, the mathematical model and calculation method established can be applied to the analysis of other similar condensation processes, can deeply reveal the physical mechanism of the condensation process, such as phase change dynamics and heat transfer law, obtain better understanding of the process, can replace part of the experimental research, reduce the research and development cost, shorten the product design cycle, can provide the quantitative relationship of various parameters on the condensation amount, establish the condensation amount prediction model, guide the engineering design and operation, can replace the field test through virtual simulation analysis, avoid the damage and accident risk of equipment, help to optimize the operation parameters, reduce the condensate accumulation, reduce the probability of equipment damage and accident occurrence, can calculate the liquid film distribution law, optimize the inner surface of the structure, reduce the liquid film blockage problem.

[0123] The following takes the containment as an example for description.

[0124] Specifically, in the embodiment of the present application, the condensation process in the containment is simulated by using a single-phase multi-component model, that is, the single-phase multi-component model is used as the condensate calculation model, which can obtain the condensate generation rate (i.e. condensate generation rate) on the wall surface, and further use the Euler liquid film model to calculate the distribution of the liquid film on the condensing surface with the condensate generation rate as the input condition. The wall / slab condensation law under different steam conditions in the containment is analyzed, and the condensate retention amount data under different wick networks is obtained.

[0125] The total heat transfer amount of the gas phase main body to the pipe wall is divided into two parts, one part is the sensible heat transferred by natural convection, and the other part is the latent heat transferred by the condensation of the steam on the condensing wall surface. The sensible heat and the latent heat are transferred to the cold fluid through the liquid film, the pipe wall and the dirt. The mass transfer driving force of the steam diffusing to the pipe wall is the difference between the steam partial pressure of the gas main flow and the saturated steam partial pressure corresponding to the liquid film temperature. When the steam diffuses to the pipe wall or the gas-liquid interface, if the temperature of the pipe wall or the gas-liquid interface is lower than the dew point temperature of the steam, the steam condenses to form a liquid film.

[0126] The condensate in the containment vessel mainly stays on the wall surface in the form of condensate film, and the amount of the condensate is positively correlated with the surface area exposed to the steam environment. The condensation calculation domain is extracted based on the containment vessel geometric model. The main condensation area in the containment vessel is the wall surface and the floor (the maintenance platform), and the area below the grid platform in the containment vessel is not included in the research scope. The surface area of the spray pipeline is small, and the condensate formed on the surface will flow into the pool, and the pipeline will cause the rapid increase of the calculation grid, so the condensate on the surface of the pipeline is ignored in the calculation model. Since the size of the support is small and it is wrapped by high-temperature steam, the condensate on the surface is small, so these structures are also ignored in the calculation model. The surfaces of the remaining heating and ventilation equipment, the maintenance platform and the main equipment are retained. The final geometric model is shown in Fig. 3. The geometric model of the containment vessel is simplified, and the grid division is performed on the simplified geometric model. Since condensation mainly occurs on the wall surface, the grid near the wall surface is encrypted, and the number of grids in each direction is 81x81x51, the height of the first layer of grids is 1 mm, and the growth factor is 1.2. The simplified geometric model is shown in Fig. 4, and the grid division of the simplified geometric model is shown in Fig. 5.

[0127] After completing the grid division, the present application adopts a single-phase multi-component method to study the condensate retention amount in the containment vessel, which can better consider the influence of non-condensable gas. In order to effectively perform the calculation, the following four points are set for the steam condensation process containing air:

[0128] (1) The influence of the liquid film during the condensation process can be ignored, and the condensate is removed during the condensation process, and the accumulation of the gas near the wall surface and the flow field distribution in the main flow area are mainly studied;

[0129] (2) The steam in the mixed gas is the saturated steam under the partial pressure, and the relationship between the saturated steam pressure P s and the wall surface temperature Tw is as follows:

[0130]

[0131] (3) Condensation only occurs in the first layer of grids near the condensation wall surface, and the saturated steam in the gas phase boundary layer may also form liquid droplets after being cooled, that is, the formation of fog. Compared with a large amount of wall condensation, the existence of the liquid droplets in the gas phase boundary layer only has a very small influence on the mass diffusion of the steam, and the liquid droplets formed in the gas phase boundary layer can be ignored;

[0132] (4) The steam-air mixed fluid is treated as a single-phase two-component fluid, and the two-component gas mixture composed of water vapor and air is assumed to be an ideal gas, and the density calculation formula is derived as follows:

[0133]

[0134] In the formula, ρmix —Density of the mixed gas, kg / m³ 3 R—molar gas constant; W v W a —Water vapor, air mass fraction; M v M a —Molar mass of water vapor and air.

[0135] The mass diffusion coefficient of a two-component mixture is calculated using the following formula:

[0136]

[0137] Where: T0, P0—temperature and pressure under standard conditions, 273.15K, 101325Pa; D0—mass diffusion coefficient under standard conditions; α—value ranges from 1.5 to 2.0.

[0138] The mass diffusion coefficient is implemented using the DEFINE_IFFUSIVITY(vapor_diffusivity,c,t,i) macro compiled into the UDF and loaded in the mixture settings of the material panel.

[0139] Based on the four assumptions above, the condensation process of air-containing vapor can be simplified: within the first grid layer of the condensation wall, convective heat transfer between the mixed gas and the wall causes a decrease in fluid temperature T. The local vapor partial pressure P is compared within the condensation wall cell. v Saturation pressure P corresponding to wall temperature s The magnitude of P is used to determine whether condensation has occurred. v >P s Condensation occurs, producing condensate volume m0 and releasing heat H0, while the condensate and latent heat are removed; conversely, the condensate volume is zero, and only convective heat transfer exists.

[0140] The convective heat transfer was calculated using FLUENT. The phase change process of condensation causes losses in mass, energy, momentum, and components of the mixed gas phase. These losses can be simulated by adding source terms to the governing equations of the condensation wall using a compiled UDF. The source term values ​​in each cell adjacent to the wall are stored using a UDM to calculate the latent heat released by the vapor at a certain moment. The wall condensation parameters are shown in Figure 6.

[0141] Governing equations:

[0142]

[0143]

[0144]

[0145]

[0146] The mass source term calculation method of the condensed liquid is:

[0147]

[0148] The mass source term calculation method of the vapor gas phase is:

[0149]

[0150] The source term of the energy equation is:

[0151]

[0152] is the density, D is the mass diffusion coefficient, is the component mass fraction, is the latent heat of vaporization, V cell is the grid cell volume, A face is the wall surface area of the cell.

[0153] In the simulation test condition, the embodiment of the application adopts steady-state calculation, and the complete condensation process adopts a synchronous format. The physical quantities corresponding to the water vapor saturation pressure of the water vapor partial pressure and the wall surface temperature of the near-wall cell are all taken from the previous iteration calculation result. According to the iteration calculation result of the previous round, it is determined whether condensation can occur. As long as the water vapor partial pressure of the near-wall cell is greater than the water vapor saturation pressure corresponding to the wall surface temperature, the current iteration will occur condensation, and the condensation mass, that is, the condensation rate, is calculated by the wall surface temperature of the current iteration.

[0154] As shown in FIG. 7, a two-dimensional model is used to verify the UDF program. Among them, the inlet velocity is 0.1 m / s, the inlet temperature is 359.31 K, the inlet water vapor mass fraction is 0.479673, the cold wall surface temperature is 330 K, and the upper wall surface is a symmetrical wall surface. FIG. 8 is the verification result, and it can be seen that the wall condensation flux calculated by the present research is almost coincided with the analytical solution in the literature, and the error is less than 20%. FIGS. 9-12 are the temperature distribution cloud map of the two-dimensional model, the water vapor and air mass fraction cloud map, and the velocity distribution cloud map. It can be seen that with the condensation, the water vapor mass fraction in the channel gradually decreases, and the air mass fraction gradually increases.

[0155] The present application is based on the single-phase multi-component condensation simulation method, opens the component transport equation, uses the user self-development platform UDF (User Defined Function) of the FLUENT software to realize the numerical simulation of condensation, and uses UDM (User Defined Memory) to store the latent heat exchange amount, so as to obtain the condensate retention amount.

[0156] The calculation precision is double precision, the numerical method is selected as pressure based solver, and the implicit coupling method is used for the velocity-pressure coupling. The method has great advantages when the parameters such as density, energy and momentum are interdependent. The second-order upwind format is used for the discretization of density, momentum, energy and component terms; the Green-Gauss cell-based method is selected for variable gradient difference method, which is suitable for quadrilateral and hexahedral grids; the second-order implicit relationship is selected to solve the mixing process of two-component gas to obtain more accurate solution. The condensing wall surface adopts the no-slip wall boundary condition, and the wall surface temperature distribution is given. During simulation, the wall surface temperature of the condensing wall surface is set, and the rest of the wall surface is treated as adiabatic.

[0157] The flow of the liquid film on the wall surface is calculated by using the Euler liquid film model. In the model and material settings of the Euler wall film model, the wall film momentum solving option needs to be activated, and the gravity option and the pressure gradient option in the momentum option need to be opened. On this basis, the extension term and the surface tension term can be opened; the liquid film material selects water as the working medium, and sets the surface tension to 0.07194 N / m. In the time and space discretization options of the Euler wall film model, to improve the calculation accuracy, the time, continuity and momentum discretization of the wall film are all selected as the second-order discretization. The coupled solution of mass and momentum equations is opened, and by default, the mass equation of the wall film is calculated first, and then the momentum equation of the wall film is calculated. When the wall film characteristic quantity, i.e. the wall film height and the velocity are coupled (such as the free falling wall film of the wave surface), the coupled solution of mass and momentum equations needs to be used. Coupled solution is mainly used in the calculation of curved wall film and wall film surface tension.

[0158] The condensate production is closely related to the internal parameters of the containment, such as the non-condensable gas content, the steam pressure, the wall surface pressure distribution, the internal flow field, etc. For the study of the condensate retention, it is necessary to distinguish between the condensate production rate and the condensate retention. When the liquid film is in a dynamic equilibrium condition, the condensed steam forms a liquid and merges into the liquid film, and the liquid film flows downward under the action of gravity. Macroscopically, the condensate entering the liquid film region has the same mass as the condensate leaving the liquid film, and the liquid film is in a relatively stable state. The mass of this relatively stable liquid film is the condensate retention of the cooling medium.

[0159] Firstly, a constant condensate production rate is used as the boundary condition to analyze the liquid film distribution on the wall surface and the retention. The calculation conditions of the condensate production rate are: the pressure in the cavity is 0.3 MPa, the temperature difference is 50 ℃, and the average condensate production rate of the 6.5 m high vertical plane is about 0.1 kg / (m 2 s) according to the correlation formula.

[0160] The liquid film calculation results are shown in Figures 13-16, which respectively show the liquid film thickness distribution on the wall surface, the liquid film flow rate distribution, the liquid film mass distribution and the liquid film thickness distribution of the internal equipment. The liquid film is thicker in the area near the lower part of the top and side wall surface. The flow rate of the condensate on the top is low, and the thickness is large. The liquid film speed flows vertically downward along the side wall surface, and the flow rate is higher and higher. Due to the truncation of the maintenance platform, the liquid film is thicker above it and thinner below it.

[0161] The high-temperature steam contacts the wall surface of the containment vessel with a lower temperature, and condensation occurs on the wall surface. The condensate flows down along the wall surface to form a liquid film. From the perspective of reducing the temperature of the containment vessel, the more condensate produced per unit area, the more heat dissipated through the containment vessel, which helps to reduce the temperature and pressure inside the containment vessel. However, the more condensate produced per unit area, the thicker the water film, and the more cooling medium retained in the containment vessel, which reduces the water level of the circulating pump water pool and is not conducive to the stable operation of the system. The Euler liquid film model can be used to specify the area where the liquid film is generated. Since this model verification work only specifies the generation of liquid film on the peripheral surface, the liquid film thickness in the internal area is 0 mm. Under this working condition, the liquid film retention is about 198.9 kg.

[0162] In addition, the electronic device of the present application comprises a memory and a processor; the memory is used to store a computer program; the processor is used to execute the computer program to realize the nuclear power plant condensate retention calculation method of any one of the above. Specifically, according to the embodiments of the present application, the processes described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments of the present application include a computer program product comprising a computer program carried on a computer readable medium, the computer program comprising program code for executing the method shown in the flowchart. In such embodiments, the computer program can be downloaded and installed by the electronic device and executed to perform the above-mentioned functions defined in the method of the embodiments of the present application. The electronic device in the present application can be a notebook, desktop, tablet computer, smart phone and other terminals, or a server.

[0163] In addition, the present application also provides a storage medium storing a computer program, which is executed by a processor to implement the nuclear power plant condensate holdup calculation method according to any one of the above. Specifically, it should be noted that the storage medium of the present application can be a computer readable signal medium or a computer readable storage medium or any combination of the above two. The computer readable storage medium may, for example, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or apparatus, or any combination of the above. More specific examples of the computer readable storage medium can include, but are not limited to, an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, the computer readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, device or apparatus. In the present application, the computer readable signal medium can include a data signal carried in a baseband or as a part of a carrier wave, which carries computer readable program code. Such a propagated data signal can take various forms, including but not limited to an electromagnetic signal, an optical signal or any suitable combination of the above. The computer readable signal medium can also be any computer readable medium other than the computer readable storage medium, which can send, propagate or transmit a program for use by or in conjunction with an instruction execution system, device or apparatus. The program code contained in the computer readable medium can be transmitted by any suitable medium, including but not limited to a wire, a cable, an RF (radio frequency) or the like, or any suitable combination of the above.

[0164] The above computer readable medium can be contained in the above electronic device; or can exist separately and not be assembled into the electronic device.

[0165] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method part.

[0166] Those skilled in the art will further realize that the mere conception of the examples described herein is not inducing the patentable subject matter recited in each claim. The combinations and / or sequences of various example elements, steps, operations, actions, and / or functions described in each example are not necessarily the only possible combinations and / or sequences for practicing the claimed subject matter. Those skilled in the art will further realize that the mechanisms of the various examples described herein are for implementing the several embodiments and are not meant to be limiting as to the scope of the claimed subject matter. That is, the protection afforded to the claimed subject matter is not limited to the mechanisms of practicing the described examples. Therefore, the claimed subject matter should be understood to encompass a variety of subject matter, and equally obvious to those in the art, including but not limited to the following:

[0167] The steps of a method or algorithm described in connection with the examples disclosed herein can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module can reside in RAM, flash memory, ROM, electrically programmable ROM (EPROM or EEPROM), registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor. The processor and the storage medium can reside in an ASIC.

[0168] The examples described herein are only intended to illustrate the technical concepts and features of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it accordingly, and cannot limit the protection scope of the present application. Any equivalent changes and modifications made within the scope of the claims of the present application shall be included in the scope of the claims of the present application.

Claims

1. A method of calculating a condensate holdup amount in a nuclear power plant, characterized by, The method comprises the following steps: establishing a condensate retention amount analysis geometric model of an object to be analyzed, and performing mesh division on the geometric model to obtain a three-dimensional mesh model; calculating the three-dimensional mesh model by using a single-phase multi-component model to obtain flow field and component distribution of gas-liquid two phases in a phase change process; based on the flow field and component distribution of the gas-liquid two phases in the phase change process, and in combination with a control equation of the object to be analyzed on a condensation wall surface, calculating a condensate generation rate on the condensation wall surface; based on the condensate generation rate, calculating a distribution of a liquid film on the condensation wall surface; according to the distribution of the condensation wall surface, adjusting calculation conditions to analyze wall surface condensation rules under different steam conditions, and obtaining condensate retention amount data of the condensation wall surface.

2. The nuclear power plant condensate holdup calculation method according to claim 1, characterized by, The step of establishing a condensate retention amount analysis geometric model of an object to be analyzed, and performing mesh division on the geometric model to obtain a three-dimensional mesh model comprises: establishing a three-dimensional geometric model of the object to be analyzed according to a structure shape and size of the object to be analyzed; simplifying the three-dimensional geometric model according to a structure function and working condition of the object to be analyzed to obtain a simplified three-dimensional model; performing mesh division on the simplified three-dimensional model to obtain an initial mesh model; processing the initial mesh model to obtain the three-dimensional mesh model.

3. The nuclear power plant condensate holdup calculation method according to claim 2, characterized by, The step of processing the initial mesh model to obtain the three-dimensional mesh model comprises: extracting a fluid calculation domain required for calculation from the initial mesh model; performing smoothing and optimization processing on the fluid calculation domain mesh; determining an inlet condition, an outlet condition and a wall surface boundary condition of the fluid calculation domain mesh, completing mesh division, and obtaining the three-dimensional mesh model.

4. The nuclear power plant condensate holdup calculation method according to claim 1, characterized by, The step of calculating the three-dimensional mesh model by using a single-phase multi-component model to obtain flow field and component distribution of gas-liquid two phases in a phase change process comprises: determining a single-phase multi-component fluid in a condensation process; judging whether the fluid reaches an equilibrium state; if yes, completing a condensation transition of a steam component in a gas phase to a liquid phase through coupling of a wall surface source term; calculating a mixed gas parameter of the three-dimensional mesh model based on the single-phase multi-component model; performing iterative calculation to obtain the flow field and component distribution of the gas-liquid two phases in the phase change process.

5. The nuclear power plant condensate holdup calculation method according to Claim 1, characterized by, The step of calculating a condensate generation rate on a condensation wall surface based on the flow field and component distribution of the gas-liquid two phases in the phase change process, and in combination with a control equation of the object to be analyzed on the condensation wall surface comprises: calculating a latent heat released by steam at any time based on the flow field and component distribution of the gas-liquid two phases in the phase change process; simulating a mass source term, an energy source term and a momentum source term of the mixed gas in the phase change process according to the control equation of the condensation wall surface; calculating a component loss of the mixed gas in the phase change process; calculating an updated phase change rate in combination with a wall surface temperature according to the mass source term, the energy source term and the momentum source term; calculating a condensate generation rate on a wall surface unit at each time according to the updated phase change rate and the latent heat; performing iterative calculation to obtain the condensate generation rate on the condensation wall surface at different times.

6. The nuclear power plant condensate holdup calculation method according to claim 5, characterized by, The mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing wall surface, and the mass source term, the energy source term and the momentum source term of the mixed gas in the phase change process are simulated according to the control equation of the condensing ​ ​ ​ ​ 7. The nuclear power plant condensate holdup calculation method according to claim 5, characterized by, ​ ​ 8. The nuclear power plant condensate holdup calculation method according to claim 5, characterized by, ​ ​ ​ 9. The nuclear power plant condensate holdup calculation method according to Claim 1, characterized by, ​ ​ 10. The nuclear power plant condensate holdup calculation method according to claim 9, characterized by, ​ ​ ​ ​ ​ ​ ​ ​ 11. The nuclear power plant condensate holdup calculation method according to Claim 1, characterized by, ​ ​ ​ ​ 12. A nuclear power plant condensate holdup amount calculation device characterized by comprising: ​ ​ The phase change computing unit is configured to perform calculation on the three-dimensional grid model by using a single-phase multi-component model, to obtain a flow field and a component distribution of the gas-liquid two-phase in a phase change process; The condensate generation rate computing unit is configured to perform calculation based on the flow field and the component distribution of the gas-liquid two-phase in the phase change process, in combination with a control equation of the object to be analyzed on a condensing wall surface, to obtain a condensate generation rate on the condensing wall surface; The liquid film distribution computing unit is configured to perform calculation on a distribution of a liquid film on the condensing wall surface based on the condensate generation rate; The condensate holdup computing unit is configured to obtain condensate holdup data of the condensing wall surface by adjusting a calculation condition, and analyzing a wall condensation law under different steam conditions, according to the distribution of the condensing wall surface.

13. A storage medium, characterized by The storage medium stores a computer program, and the computer program is adapted to be loaded by a processor to execute steps of the nuclear power plant condensate holdup calculation method according to any one of claims 1 to 11.

14. An electronic device, comprising: The device comprises a memory and a processor, and the memory stores a computer program, and the processor executes steps of the nuclear power plant condensate holdup calculation method according to any one of claims 1 to 11 by calling the computer program stored in the memory.

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