A method and system for analyzing hydrogen risk in a steel containment vessel with water film cooling

Abstract

The present disclosure relates to the technical field of nuclear reactor safe operation assessment, proposes a method and system for hydrogen risk analysis in a steel containment vessel with water film cooling, constructs a water film cooling simulation model for simulating the heat and mass transfer process of the external liquid drop model of the containment vessel, transmits the simulation results to a three-dimensional hydrogen risk analysis CFD program for coupling, realizes the supplement of the CFD program, and can be applied to the three-dimensional hydrogen risk analysis of passive nuclear power plants, effectively improving the accuracy of hydrogen risk analysis after nuclear power plant accidents.

Description

Technical Field

[0001] The present disclosure relates to the technical field related to nuclear reactor safe operation assessment, and more specifically, to a method and system for analyzing hydrogen risk in a steel containment vessel with water film cooling. Background Art

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

[0003] Under severe accident conditions, oxidation of the reactor fuel cladding will produce a large amount of hydrogen. The rapid release of hydrogen in a short period of time will cause a high hydrogen concentration in local areas of the containment. In the later stages of the accident, if the reactor pressure vessel is damaged, causing the core melt to enter the reactor cavity, the reaction between the molten core and the concrete floor will also continuously release flammable gases such as hydrogen and carbon monoxide for a long time. If the hydrogen release rate exceeds the hydrogen removal rate of the hydrogen control system or the hydrogen control system is unavailable, localized hydrogen accumulation may occur in the containment, forming a flammable gas mixture. If the flammable gas encounters an ignition source, it may cause combustion or explosion. The resulting temperature or pressure load may threaten the availability of the equipment in the containment and the integrity of the containment.

[0004] At present, three-dimensional hydrogen risk analysis CFD programs are widely used internationally as a supplement to traditional system analysis programs to predict the diffusion of hydrogen / air / water vapor, as well as the recombination and combustion analysis of hydrogen in the containment under design basis accidents or severe accidents.

[0005] A key feature of passive nuclear power plants (such as CAP1400 and AP1000) is the passive containment cooling system (PCS). In the event of a design basis accident or severe accident, the most important function of the PCS is to remove heat from the containment through evaporation / condensation and convection heat transfer, ensuring that the containment pressure and temperature remain within acceptable ranges. Because the operation of the PCS affects the water vapor concentration within the containment, it indirectly affects hydrogen risk. However, current common three-dimensional hydrogen risk analysis CFD programs have significant limitations in simulating the PCS. These programs cannot simulate the liquid film flow evaporation process outside the steel containment, and thus lack boundary conditions for external simulation. This results in inaccurate simulation results inside the containment using CFD programs, and thus cannot accurately simulate steam condensation within the safe zone. Inaccurate water vapor concentrations affect hydrogen risk assessments, making them unsuitable for hydrogen risk analysis in passive nuclear power plants. Summary of the Invention

[0006] To address the above-mentioned issues, the present disclosure proposes a method and system for hydrogen risk analysis within a steel containment vessel with water film cooling. A water film cooling simulation model is coupled with a general three-dimensional hydrogen risk analysis CFD program, which is applicable to three-dimensional hydrogen risk analysis in passive nuclear power plants and effectively improves the accuracy of hydrogen risk analysis after nuclear power plant accidents.

[0007] In order to achieve the above objectives, the present disclosure adopts the following technical solutions:

[0008] One or more embodiments provide a method for analyzing hydrogen risk in a steel containment vessel with water film cooling, comprising the following steps:

[0009] The heat transfer process inside the steel containment was simulated using the CFD software framework, and the convection and radiation heat transfer of the air-water film were simulated.

[0010] A water film cooling simulation model was constructed to simulate the flow and heat transfer process inside the water film of the steel containment and between the water film and the wall, and the convection heat transfer between the water film and the wall under the environment to be analyzed was obtained;

[0011] Assuming the surface temperature of the water film, according to the conservation of energy flowing into and out of the water film, as well as the conservation of energy transferred between the water film and the wall, and between the water film and the air, the surface temperature of the water film is adjusted and iteratively calculated to obtain the actual surface temperature of the water film;

[0012] The calculated actual water film temperature is transmitted to the CFD software framework, and the heat and mass transfer processes in the containment are re-simulated to obtain the actual water vapor concentration in the containment, thereby determining the hydrogen risk level of the containment under the environment to be analyzed.

[0013] One or more embodiments provide a hydrogen risk analysis system in a steel containment vessel with water film cooling, comprising:

[0014] CFD simulation unit: configured to simulate the heat transfer process inside the steel containment through the CFD software framework, and simulate the convection and radiation heat transfer of the air-water film;

[0015] Water film cooling simulation unit: It is configured to build a water film cooling simulation model, simulate the flow and heat transfer process of the water film inside the steel containment and between the water film and the wall, and obtain the convection heat transfer between the water film and the wall under the environment to be analyzed;

[0016] Water film temperature solver: This unit is configured to assume the surface temperature of the water film, adjust the surface temperature of the water film based on the conservation of energy flowing into and out of the water film, and the conservation of energy transferred between the water film and the wall, and between the water film and the air, and then iteratively calculate the actual surface temperature of the water film.

[0017] Coupling judgment unit: It is configured to transmit the calculated actual water film temperature to the CFD software framework, re-simulate the heat and mass transfer process in the containment, obtain the actual water vapor concentration in the containment, and then determine the hydrogen risk level of the containment under the environment to be analyzed.

[0018] An electronic device includes a memory and a processor, and computer instructions stored in the memory and executed on the processor. When the computer instructions are executed by the processor, the steps of the above method are completed.

[0019] A computer-readable storage medium is used to store computer instructions, and when the computer instructions are executed by a processor, the steps of the above method are completed.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] In this disclosure, a water film cooling simulation model is constructed to simulate the heat and mass transfer process of the liquid drop outside the containment vessel. The simulation results are transmitted to the three-dimensional hydrogen risk analysis CFD program for coupling to supplement the CFD program. It can be applied to the three-dimensional hydrogen risk analysis of passive nuclear power plants and effectively improve the accuracy of hydrogen risk analysis after nuclear power plant accidents.

[0022] The advantages of the present disclosure and additional advantages will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which constitute a part of the present disclosure, are used to provide a further understanding of the present disclosure. The exemplary embodiments of the present disclosure and their descriptions are used to explain the present disclosure but do not constitute a limitation of the present disclosure.

[0024] Figure 1 Schematic diagram of heat exchange of a steel containment vessel with water film cooling according to Example 1 of the present disclosure;

[0025] Figure 2 This is a structural diagram of the coupling between the water film simulation model and the CFD software framework of Example 1 of the present disclosure;

[0026] Figure 3 This is a schematic diagram of iterative calculation of the water film surface temperature in Example 1 of the present disclosure;

[0027] Figure 4 It is a schematic diagram of the falling liquid film flow changes in Example 1 of the present disclosure. DETAILED DESCRIPTION

[0028] The present disclosure will be further described below with reference to the accompanying drawings and embodiments.

[0029] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present disclosure belongs.

[0030] It should be noted that the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof. It should be noted that, in the absence of conflict, the various embodiments in the present disclosure and the features in the embodiments can be combined with each other. The embodiments will be described in detail below with reference to the accompanying drawings.

[0031] Example 1

[0032] In the technical solutions disclosed in one or more embodiments, Figures 1 to 3 As shown, a method for hydrogen risk analysis in a steel containment with water film cooling includes the following steps:

[0033] Step 1: Obtain the containment environment parameter data to be analyzed;

[0034] The environment to be analyzed may be the environment inside the containment vessel after a severe accident in a nuclear power plant, and environmental parameters in this environment are obtained;

[0035] Step 2: Use the CFD software framework to simulate the heat transfer process inside the steel containment, and simulate the convection and radiation heat transfer of the air-water film;

[0036] Specifically, a CFD software framework that simulates heat conduction, heat transfer, and condensation and evaporation processes is used to determine the convective and radiative heat transfer of the air-water film in the environment to be analyzed;

[0037] Step 3: Construct a water film cooling simulation model to simulate the flow and heat transfer process of the water film outside the steel containment, and obtain the convection heat transfer between the water film and the wall under the environment to be analyzed;

[0038] Step 4: Assuming the surface temperature of the water film, based on the conservation of energy flowing into and out of the water film, as well as the conservation of energy transferred between the water film and the wall, and between the water film and the air, the water film temperature is iteratively calculated to obtain the actual surface temperature of the water film;

[0039] Step 5: The calculated actual water film temperature is transmitted to the CFD software framework, and the heat and mass transfer process in the containment is re-simulated to obtain the actual water vapor concentration in the containment. The hydrogen risk level of the containment under the environment to be analyzed is determined by the concentration ratio of water vapor to other gases in the containment.

[0040] In this embodiment, a water film cooling simulation model is constructed and coupled with a three-dimensional hydrogen risk analysis CFD program to supplement the CFD program. It can be applied to the three-dimensional hydrogen risk analysis of passive nuclear power plants and effectively improve the accuracy of hydrogen risk analysis after nuclear power plant accidents.

[0041] Specifically, in step 5, the calculated result of the water film temperature is transmitted to the CFD software framework, and the simulation model of the CFD software framework is coupled to calculate the temperature of the steel containment using the actual temperature of the water film. The water vapor condensation process inside the steel containment is corrected to obtain the actual concentration of water vapor in the containment, and determine the hydrogen risk level of the containment under the environment to be analyzed.

[0042] Furthermore, after obtaining the water vapor concentration in the containment, the risk of combustion or explosion can be determined by the ratio of water vapor, hydrogen and oxygen concentrations, thereby determining the hydrogen risk level of the containment under the environment to be analyzed.

[0043] Furthermore, the water film cooling simulation model also includes a water film morphology model, which calculates the water film evaporation rate under the current grid through the water film temperature to obtain the water film morphology, and the water film coverage of the outside can be determined through the water film morphology.

[0044] In step 1, the containment environmental parameters include the containment wall temperature, the flow rate, pressure, temperature and gas composition of the pipeline leakage point inside the containment. These environmental parameter data are used to analyze the gas components based on the CFD software framework to obtain the concentration of each gas component. However, the existing CFD software framework does not have the ability to simulate the heat transfer between the water film and the wall, nor the heat transfer simulation inside the water film. This makes the CFD software framework inaccurate in calculating the water vapor concentration, which affects the accurate judgment of the explosion probability.

[0045] In order to accurately assess the risk of explosion, it is necessary to accurately calculate the concentration of each gas, thereby correcting the detected concentration value and improving the accuracy of the safety assessment.

[0046] In step 2, the CFD software framework includes: a solid thermal conduction model, a convection heat transfer model, a radiation heat transfer model, and a condensation and evaporation model. Each model is a native model of the CFD framework. In this embodiment, the CFD software framework simulates the heat and mass transfer processes within the containment and in the water film and air.

[0047] In this embodiment, the CFD software framework can simulate the heat and mass transfer process inside the water film as well as the heat and mass transfer process between the water film and the wall.

[0048] Among them, the solid thermal conduction model is used to realize solid thermal conduction simulation; the convection heat transfer model is used to simulate the heat transfer between the fluid and the solid surface when the fluid flows through the solid; the radiation heat transfer model is used to simulate the heat transfer between the surfaces of objects under the combined action of radiation and absorption; the condensation and evaporation model is used to simulate the vapor-liquid changes of the liquid.

[0049] The important physical phenomena of PCS are heat transfer and mass transfer, such as Figure 1 The figure shows a schematic diagram of heat exchange of a steel containment with water film cooling, wherein an internal water film and an external water film are provided on both sides of the containment, and the water films transfer heat and mass with the inside and outside of the containment respectively.

[0050] PCS heat transfer methods include phase change heat transfer, convection heat transfer and thermal radiation. Among them, phase change heat transfer is the main heat transfer method, which includes water film evaporation and water vapor condensation; the mass transfer method is water film evaporation and water vapor condensation.

[0051] The key physical models involved in the heat and mass transfer analysis of PCS include the mixed gas-structure convection heat transfer model, the condensation and evaporation model, the solid thermal conduction model, the water film-wall convection heat transfer model, the thermal radiation model, the water film morphology model, etc.

[0052] The general three-dimensional CFD hydrogen risk analysis program does not have a water film morphology model or a water film-wall convection heat transfer model. This embodiment proposes a water film cooling simulation model that implements water film morphology simulation and water film-wall convection heat transfer simulation. When coupled with the general three-dimensional CFD hydrogen risk analysis program, it can realize PCS simulation capabilities.

[0053] In step 3, the water film cooling simulation model includes constructing a water film-wall convection heat transfer model, using the Chun-Seban relationship to solve the water film-wall convection heat transfer coefficient, and determining the convection heat transfer between the water film and the wall under the environmental parameters to be analyzed.

[0054] In this embodiment, the medium of the liquid model used is water, called water film, which can be replaced by any other liquid substance to form a liquid film. The technical solution of this embodiment is not limited to the water film in this embodiment, and is also applicable when replaced by other media.

[0055] When the PCS is running, the flowing water film on the outer wall of the steel containment will undergo convective heat transfer with the containment wall, absorbing heat through the form of sensible heat rise or evaporation of the water film. After considering the surface fluctuation of the water film, the Nusselt condensation heat transfer theory relationship is modified, and the water film-wall convective heat transfer coefficient is It can be solved by the Chun-Seban relationship, and the calculation formula is:

[0056] (1)

[0057] in, is the average density of the water film, also known as the mainstream water film density; is the average thermal conductivity of the water film, also known as the mainstream thermal conductivity of the water film; is the average dynamic viscosity of the water film, also known as the mainstream dynamic viscosity of the water film, g is the acceleration of gravity, is the water film Reynolds number.

[0058] The Chun-Seban relationship is the convective heat transfer relationship between the water film and the wall under falling liquid film conditions.

[0059] Furthermore, the water film cooling simulation model also includes constructing a water film morphology model, which is configured to calculate the water film thickness, critical water film thickness and water film coverage to obtain water film morphology analysis results.

[0060] Based on the water film morphology analysis results and the risk assessment results obtained in step 5, the safety level of the containment under the environment to be analyzed is confirmed after fusion.

[0061] In some embodiments, since the water film thickness is much smaller than the containment diameter, the water film is approximated as a flat falling film. The water film thickness can be calculated using the Asali theoretical formula:

[0062] (2)

[0063] in, is the kinematic viscosity, is the Reynolds number, is the mass flow rate per unit width, is the water film density.

[0064] Asali theory is the relationship between the thickness of the flat falling film water film.

[0065] For the calculation of water film thickness, the water film of passive containment cooling belongs to the falling liquid film flow outside the large-diameter cylinder, and its water film thickness is much smaller than the diameter of the containment. Therefore, the inner and outer water films of the containment can be approximated as flat plate falling films.

[0066] Through relevant experimental research, it is found that the water film thickness decreases at the beginning of evaporation, and the coverage rate remains unchanged; as the evaporation rate continues to increase, the water film thickness reaches a critical thickness and will no longer decrease, while the water film coverage rate begins to decrease. Therefore, the judgment of the critical thickness is crucial for the calculation of water film evaporation. Figure 4As shown, during the downward evaporation process of the falling liquid film, after it becomes less than the critical thickness, the width becomes narrower and the thickness remains unchanged, and the thickness is in the direction perpendicular to the plane shown in the figure.

[0067] In some embodiments, for the calculation of the critical water film thickness, specifically, in this embodiment, the envelope experiment verification can be performed using the minimum unit width mass flow rate of 49.6 g / s·m (i.e., Γmin) corresponding to the critical film thickness of Westinghouse's LST, SST, and Flat Plate experiments. The critical water film thickness can be obtained by substituting it into formula (2).

[0068] In some embodiments, for water film coverage calculation:

[0069] Define m as the mass flow rate of the water film liquid film, in kg / s; is the evaporation rate, in units of ; L is the wetted width of the water film, in meters; Γ is the mass flow rate per unit width, in meters , Z is the height of the containment wall grid, and the subscript n represents the grid number, then:

[0070]

[0071] Differentiating it yields:

[0072] In the stage where the water film width remains unchanged:

[0073]

[0074] Water film thickness constant stage:

[0075]

[0076] The liquid film coverage can be expressed as:

[0077]

[0078] Where A is the total area of the containment wall;

[0079] The energy per unit area removed by evaporation of the liquid film can be expressed as:

[0080]

[0081] in, is the latent heat of vaporization.

[0082] In step 4, the water film cooling simulation model also includes a water film temperature model, which is configured to implement iterative calculation of the water film temperature and obtain the water film surface temperature by iterative calculation based on energy conservation.

[0083] In the iterative calculation, the water film temperature is iterated according to the relationship between the mainstream temperature of the water film, the surface temperature of the water film and the physical properties of the water film, as well as the conservation of energy.

[0084] Optionally, the water film properties include the water film dynamic viscosity, latent heat of vaporization, thermal conductivity and enthalpy, and the relationship is as follows:

[0085] Water film dynamic viscosity (g / (cm﹒s)) is the mainstream temperature of the water film Function:

[0086]

[0087] Latent heat of vaporization of water film (kJ / kg) is the surface temperature of the water film Function:

[0088]

[0089] Water film thermal conductivity (w / (cm﹒K)) is the mainstream temperature of the water film Function:

[0090]

[0091] Among them, the mainstream temperature is the average of the containment wall temperature and the water film surface temperature;

[0092] The water film enthalpy h (J / g) is the mainstream temperature of the water film Function:

[0093]

[0094] The water film surface temperature It needs to be solved through iteration, such as Figure 3 As shown, the iterative steps are as follows:

[0095] (1) Assume that the outer surface temperature of a water film is , the outer surface of the water film is the surface in contact with the air;

[0096] (2) According to the outer surface temperature of the water film , the convection heat transfer coefficient Hconv and the thermal radiation heat transfer coefficient Hrad between the air and the water film are obtained through the CFD framework calculation module;

[0097] (3) According to the heat transfer coefficient between air and water film, calculate the convection heat transfer and radiation heat transfer between air and water film to obtain the total heat transfer between water film and air;

[0098] Specifically, the evaporation mass transfer coefficient between air and water film is calculated according to the Chilton-Colburn relationship: , and according to the water vapor saturation density on the water film surface , calculate the evaporation rate of the water film and evaporation heat transfer ;

[0099] The total heat exchange between water film and air is :

[0100]

[0101] in, is the mixed gas temperature; is the area of convective heat transfer; is the area where phase change occurs, that is, the surface area of the water film within the grid; is the latent heat of vaporization.

[0102] The Chilton-Colburn relationship is the Chilton-Colburn heat and mass transfer analogy relationship, which can be obtained by calling the CFD framework calculation module.

[0103] (4) Calculate the convective heat transfer between the water film and the wall based on the convective heat transfer coefficient obtained from the water film-wall heat transfer model;

[0104] First calculate the water film Reynolds number, which is , according to the convection heat transfer coefficient between water film and wall , and then through the containment wall temperature and water film surface temperature Calculate the convective heat transfer between the water film and the wall :

[0105]

[0106] (5) Determine the inflow energy of the water film and outflow energy .

[0107]

[0108]

[0109] in, is the incoming mass flow rate of the water film, is the outflow mass flow rate of the water film, and h is the enthalpy of the water film.

[0110] (6) Determine whether the energy of the input and output water films is equal. If not, adjust the surface temperature of the water film until the energy of the input and output water films is equal to obtain the actual surface temperature of the water film.

[0111] Specifically, iterative calculation and if + and + If they are not equal, then go back to the first step and adjust The value of , continue the subsequent iteration steps until + and + The difference is less than the acceptance criterion ε, which is 0.01×min( + , + ).

[0112] In step 5, the calculated results of the water film temperature are transmitted to the CFD software framework, and the simulation model of the CFD software framework is coupled to obtain the corrected containment wall temperature, and the condensation heat transfer process inside the containment is further obtained to determine the water vapor concentration inside the containment, thereby determining the hydrogen risk level of the containment under the environment to be analyzed.

[0113] Example 2

[0114] Based on Example 1, this embodiment provides a hydrogen risk analysis system in a steel containment vessel with water film cooling, comprising:

[0115] CFD simulation unit: configured to simulate the heat transfer process inside the steel containment through the CFD software framework, and simulate the convection and radiation heat transfer of the air-water film;

[0116] Water film cooling simulation unit: It is configured to build a water film cooling simulation model, simulate the flow and heat transfer process of the water film inside the steel containment and between the water film and the wall, and obtain the convection heat transfer between the water film and the wall under the environment to be analyzed;

[0117] Water film temperature solver: This unit is configured to assume the surface temperature of the water film, adjust the surface temperature of the water film based on the conservation of energy flowing into and out of the water film, and the conservation of energy transferred between the water film and the wall, and between the water film and the air, and then iteratively calculate the actual surface temperature of the water film.

[0118] Coupling judgment unit: It is configured to transmit the calculated actual water film temperature to the CFD software framework, re-simulate the heat and mass transfer process in the containment, obtain the actual water vapor concentration in the containment, and then determine the hydrogen risk level of the containment under the environment to be analyzed.

[0119] It should be noted here that the various modules in this embodiment correspond one-to-one to the various steps in Example 1, and the specific implementation processes are the same, which will not be repeated here.

[0120] Example 3

[0121] This embodiment provides an electronic device, including a memory and a processor, and computer instructions stored in the memory and running on the processor. When the computer instructions are run by the processor, the steps described in the method of embodiment 1 are completed.

[0122] Example 4

[0123] This embodiment provides a computer-readable storage medium for storing computer instructions. When the computer instructions are executed by a processor, the steps described in the method of embodiment 1 are completed.

[0124] The foregoing description is merely a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present disclosure shall be included within the scope of protection of the present disclosure.

Claims

1. A method for analyzing hydrogen risk in a steel containment vessel with water film cooling, characterized in that: The steps include: The heat transfer process inside the steel containment was simulated using the CFD software framework, and the convection and radiation heat transfer of the air-water film were simulated. Construct a water film cooling simulation model to simulate the flow and heat transfer of the water film outside the steel containment. The process is used to obtain the heat transfer between the water film and the wall under the environment to be analyzed; Assuming the surface temperature of the water film, according to the conservation of energy flowing into and out of the water film, as well as the conservation of energy transferred between the water film and the wall, and between the water film and the air, the surface temperature of the water film is adjusted and iteratively calculated to obtain the actual surface temperature of the water film; The calculated actual water film temperature is transmitted to the CFD software framework, and the heat and mass transfer processes in the containment are re-simulated to obtain the actual water vapor concentration in the containment, thereby determining the hydrogen risk level of the containment under the environment to be analyzed.

2. The method for analyzing hydrogen risk in a steel containment vessel with water film cooling according to claim 1, characterized in that: Based on the actual temperature of the water film after calculation, the CFD software framework is used to re-simulate the heat and mass transfer processes in the containment. Specifically, the temperature of the steel containment is calculated based on the actual temperature of the water film based on the CFD software framework, and the water vapor condensation process inside the steel containment is corrected to obtain the water vapor concentration in the containment.

3. The method for analyzing hydrogen risk in a steel containment vessel with water film cooling according to claim 1, wherein: After obtaining the water vapor concentration in the containment, the risk of explosion is determined by the ratio of water vapor, hydrogen and oxygen concentrations, thereby determining the hydrogen risk level of the containment under the environment to be analyzed.

4. The method for analyzing hydrogen risk in a steel containment vessel with water film cooling according to claim 1, wherein: The CFD software framework includes: solid heat conduction model, convection heat transfer model, radiation heat transfer model, condensation and evaporation model, which simulates the heat and mass transfer process of water film and air in the containment; The solid heat conduction model is used to simulate solid heat conduction; the convection heat transfer model is used to simulate the heat transfer between the fluid and the solid surface when the fluid flows through the solid; the radiation heat transfer model is used to simulate the heat transfer between the surfaces of objects under the combined action of radiation and absorption; the condensation and evaporation model is used to simulate the vapor-liquid changes of the liquid.

5. The method for analyzing hydrogen risk in a steel containment vessel with water film cooling according to claim 1, wherein: The water film cooling simulation model includes a constructed water film-wall convection heat transfer model and uses the Chun-Seban relationship to solve the water film-wall convection heat transfer coefficient.

6. The method for analyzing hydrogen risk in a steel containment vessel with water film cooling according to claim 1, characterized in that: The water film cooling simulation model also includes constructing a water film morphology model, which is configured to calculate the water film thickness, critical water film thickness, and water film coverage, and obtain water film morphology analysis results; When calculating the water film thickness, the water film is approximated as a flat falling film.

7. The method for analyzing hydrogen risk in a steel containment vessel with water film cooling according to claim 1, wherein: The iterative calculation of the water film temperature involves the following steps: Assume the outer surface temperature of a water film is; According to the outer surface temperature of the water film, the convection heat transfer coefficient and thermal radiation heat transfer coefficient between the air and the water film are obtained through the CFD framework calculation module; According to the heat transfer coefficient between air and water film, the convection heat transfer and radiation heat transfer between air and water film are calculated to obtain the total heat transfer between water film and air; Calculate the convective heat transfer between the water film and the wall based on the convective heat transfer coefficient obtained from the water film-wall heat transfer model; Determine whether the energy of the input and output water films is equal. If not, adjust the water film surface temperature until the energy of the input and output water films is equal to obtain the actual temperature of the water film surface.

8. A hydrogen risk analysis system in a steel containment vessel with water film cooling, characterized in that: include: CFD simulation unit: configured to simulate the heat transfer process inside the steel containment through the CFD software framework, and simulate the convection and radiation heat transfer of the air-water film; Water film cooling simulation unit: It is configured to build a water film cooling simulation model to simulate the flow and heat transfer process of the water film outside the steel containment, and obtain the convection heat transfer between the water film and the wall under the environment to be analyzed; Water film temperature solver: This unit is configured to assume the surface temperature of the water film, adjust the surface temperature of the water film based on the conservation of energy flowing into and out of the water film, and the conservation of energy transferred between the water film and the wall, and between the water film and the air, and then iteratively calculate the actual surface temperature of the water film. Coupling judgment unit: It is configured to transmit the calculated actual water film temperature to the CFD software framework, re-simulate the heat and mass transfer process in the containment, obtain the actual water vapor concentration in the containment, and then determine the hydrogen risk level of the containment under the environment to be analyzed.

9. An electronic device, characterized in that: The method comprises a memory and a processor, and computer instructions stored in the memory and executed on the processor, wherein when the computer instructions are executed by the processor, the steps of any one of the methods of claims 1 to 7 are completed.

10. A computer-readable storage medium, characterized in that Used to store computer instructions, which, when executed by a processor, complete the steps of any one of the methods of claims 1 to 7.

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