A kind of open hole core barrel and design method, design device and storage medium

Abstract

This invention discloses an open-type reactor core shroud, its design method, design device, and storage medium. The method involves collecting pressure vessel structural data and shroud structural data; performing CFD simulations based on the pressure vessel structural data and the shroud structural data to determine temperature data under typical operating conditions, including temperature distribution and temperature gradient; determining the location of the open layer based on the temperature data; setting a aperture ratio; setting different aperture diameters based on the aperture ratio; determining the number of apertures based on the shroud structural data and the aperture diameters; adding the open layer location, aperture diameter, and number of apertures to the shroud structural data; calculating the natural circulation drive head and aperture flow resistance corresponding to the updated shroud structural data; and saving the updated shroud structural data if the natural circulation drive head is greater than the aperture flow resistance.

Description

Technical Field

[0001] This invention relates to the field of nuclear power reactor primary loop pressure control technology, specifically to an open-hole reactor core shroud and its design method, design device and storage medium. Background Technology

[0002] Integrated natural circulation reactors typically employ steam-gas self-regulating technology to control the primary coolant circuit pressure. This technology integrates the pressure stabilization space at the top of the reactor pressure vessel. A perforated conduit structure is usually installed below the primary coolant level in the lower part of the pressure stabilization chamber. This conduit serves two purposes: firstly, it creates a flow channel for the coolant within the reactor, guiding the circulation of the primary coolant; secondly, as an internal component, it provides support and protection for internal parts such as instrumentation tubes. Furthermore, during transient conditions such as control rod actuator movement or control rod descent, the perforations on the conduit provide a flow path for the coolant inside and outside the conduit, reducing coolant discharge resistance and thus minimizing fluid obstruction affecting moving parts.

[0003] Existing core shroud opening designs primarily focus on mechanical structural strength requirements and meeting coolant discharge needs under transient operating conditions. Opening parameters are typically determined based on empirical design or structural layout requirements, without fully considering the coupling relationship between the shroud opening structure and the reactor's thermal-hydraulic characteristics. For example, in terms of opening location design, existing schemes usually adopt a uniform arrangement or are set according to installation space, without optimizing for temperature distribution and coolant flow conditions in the pressurized gas chamber region. Regarding opening diameter design, a uniform diameter is typically used, without considering the differences in coolant flow requirements at different shroud heights. In terms of opening direction design, straight-through hole structures arranged radially along the shroud are often used, without further considering the impact of the hole direction on coolant flow path, mixing effect, and local flow resistance.

[0004] Patent document CN111599495A discloses a two-phase natural circulation integrated reactor, including a pressure vessel and a basket inside the pressure vessel, a reactor core located at the bottom of the basket, a space above the reactor core inside the basket being the primary loop core outlet chamber, and a heat exchange zone connected to the secondary loop on the outer periphery of the top of the basket; the first steam generated by the reactor core enters the heat exchange zone through the primary loop core outlet chamber, heats the cooling water provided by the secondary loop into second steam, converts it into condensate, and returns it to the reactor core; the second steam is delivered to the secondary loop. However, the paper does not address the issue of coordinating the design of the circumferential opening parameters based on the reactor's thermal-hydraulic characteristics to meet the requirements of natural circulation performance and transient flow resistance control.

[0005] Patent document CN108766592A discloses a flash-driven, fully natural circulation integrated pressurized water reactor, including a reactor pressure vessel, a direct-current steam generator placed inside the pressure vessel, a control rod drive mechanism, and a reactor core. The interior of the pressure vessel is divided into a cylindrical ascending channel and an annular descending channel by a core basket. No main pump is installed inside the reactor pressure vessel. The coolant flows in the ascending and descending channels through a two-phase natural circulation driven by flash evaporation, transferring heat from the reactor core to the direct-current steam generator. However, the paper does not address the issue of coordinating the design of the shroud opening parameters based on the reactor's thermal-hydraulic characteristics to meet the requirements of natural circulation performance and transient flow resistance control.

[0006] In summary, neither of the two existing patents addresses the problem of coordinating the design of the casing opening parameters based on the reactor's thermal-hydraulic characteristics to achieve both natural circulation performance and transient flow resistance control. Summary of the Invention

[0007] Based on the above-mentioned technical problems, this invention proposes an open core shroud and its design method, design device and storage medium, which solves the problem of coordinating the design of the shroud opening parameters according to the reactor's thermal-hydraulic characteristics to meet the requirements of natural circulation performance and transient flow resistance control.

[0008] To achieve the above objectives, this invention proposes a design method for an open core casing.

[0009] A method for designing an open core casing includes: Collect structural data of the pressure vessel and its casing; Based on the pressure vessel structure data and the casing structure data, CFD data simulation is performed to determine the temperature data under typical operating conditions. The temperature data includes temperature distribution and temperature gradient. The location of the perforation layer is determined based on the temperature data; the aperture ratio is set, and the opening diameter of different holes is set according to the aperture ratio; the number of openings is determined according to the surrounding cylinder structure data and the opening diameter. The data is added to the cylindrical structure data based on the location of the perforation layer, the diameter of the perforation, and the number of perforations. The natural circulation drive head and the flow resistance of the perforation are calculated for the updated cylindrical structure data. If the natural circulation drive head is greater than the flow resistance of the perforation, the updated cylindrical structure data is saved.

[0010] Furthermore, it also includes: setting a deflection angle of the circumferential direction of some openings that is inclined to the radius direction of the surrounding tube, with the deflection angle ranging from 15° to 30°.

[0011] Further, based on the pressure vessel structure data and the shroud structure data, CFD data simulation is performed to determine the temperature data under typical operating conditions. This includes: inputting the pressure vessel structure data and the shroud structure data into CFD simulation software, setting cooling medium parameters to construct a three-dimensional fluid simulation model, setting boundary conditions corresponding to the typical operating conditions, the boundary conditions including inlet flow rate, inlet temperature, pressure boundary, and core heat source distribution parameters, performing data simulation on the three-dimensional fluid simulation model using the CFD simulation software to obtain the temperature field, extracting the temperature distribution corresponding to the axial direction of the shroud based on the temperature field, and calculating the temperature gradient based on the temperature distribution.

[0012] Further, determining the location of the opening layer based on the temperature data includes: extracting the height corresponding to the maximum value in the temperature gradient and calculating the upper and lower limits of the opening.

[0013] Furthermore, the expressions for the upper and lower limits are as follows: , ,in, The lower limit is the position mentioned above. The upper limit bit, The height corresponding to the maximum value in the temperature gradient. For positional weights, This represents the total height of the gas phase space.

[0014] Further, setting different opening diameters for different holes according to the aperture ratio includes: the aperture ratio being the ratio of the maximum and minimum opening diameters; multiple openings being arranged in layers along the axial direction of the casing to form an opening layer; the opening diameter of each layer decreasing uniformly from bottom to top along the axial direction of the casing according to a preset gradient, so that the maximum opening diameter and the minimum opening diameter satisfy the aperture ratio; the opening diameters corresponding to the opening layers located at the upper and lower limits are preset according to empirical values, and the opening diameters corresponding to other opening layers are set accordingly.

[0015] Furthermore, it also includes: setting a temperature difference threshold between adjacent perforated layers, and setting the number of perforated layers according to the temperature difference threshold.

[0016] Furthermore, the number of openings is determined based on the cylindrical structure data and the opening diameter, and its expression is as follows: ,in The number of openings corresponding to each layer, Where d is the diameter of the cylindrical structure in the cylindrical structure data, and d is the diameter of the opening corresponding to that layer. For diameter weights.

[0017] Further, calculating the natural circulation driving head and orifice flow resistance corresponding to the updated cylindrical structure data includes: modifying the cylindrical structure data and reconstructing a three-dimensional fluid simulation model based on the orifice layer position, the orifice diameter, and the number of orifices; obtaining verification parameters based on the three-dimensional fluid simulation model, the verification parameters including gas density difference, effective natural circulation height, gas velocity at the orifice, and gas density at the orifice; and calculating the natural circulation driving head and the orifice flow resistance based on the verification parameters.

[0018] Further, the verification parameters obtained based on the three-dimensional fluid simulation model include: obtaining the gas density difference between adjacent regions by performing data simulation based on the three-dimensional fluid simulation model; calculating the effective height of natural circulation based on the difference between the upper limit and the lower limit in the position of the opening layer; and extracting the gas velocity and gas density of the grid simulation corresponding to different openings in the three-dimensional fluid simulation model.

[0019] Further, the natural circulation drive head and the orifice flow resistance are calculated based on the verification parameters, including: , ,in The natural circulation drive head, The gas density difference; It is the acceleration due to gravity; The effective height of the natural circulation; The flow resistance of the opening, The drag coefficient is the aperture diameter. The gas density at the opening is [the specified value]. The gas flow rate at the opening is described.

[0020] Furthermore, it also includes: if the natural circulation driving head is less than the orifice flow resistance, then the position of the orifice layer, the orifice diameter, or the number of orifices is adjusted, and the above calculation process is repeated to iterate the cylindrical structure data until the natural circulation driving head is greater than the orifice flow resistance.

[0021] To achieve the above objectives, the present invention also proposes a perforated core casing design device.

[0022] An open-hole core casing design device, comprising: The data acquisition module is used to acquire structural data of the pressure vessel and the surrounding structure data. A construction module is used to perform CFD data simulation based on the pressure vessel structure data and the casing structure data to determine temperature data under typical working conditions, wherein the temperature data includes temperature distribution and temperature gradient. The parameter module is used to determine the location of the perforation layer based on the temperature data; set the aperture ratio; set the opening diameter of different holes based on the aperture ratio; and determine the number of openings based on the surrounding cylinder structure data and the opening diameter. The verification module is used to add the opening layer position, the opening diameter and the number of openings to the cylindrical structure data, calculate the natural circulation driving head and the opening flow resistance corresponding to the updated cylindrical structure data, and save the updated cylindrical structure data if the natural circulation driving head is greater than the opening flow resistance.

[0023] To achieve the above objectives, the present invention also proposes an open core casing, wherein the open core casing is provided with openings corresponding to the position of the opening layer, the diameter of the opening and the number of openings obtained based on the above-mentioned open core casing design method.

[0024] Based on the above technical solution, the present invention has at least the following beneficial effects: 1. This invention proposes an open-aperture core casing, its design method, design device, and storage medium. By using CFD simulations of pressure vessel and core casing structural data to obtain temperature data under typical operating conditions, it characterizes the differences in circumferential and axial thermal properties of the core casing, avoiding the problem in existing technologies where the opening position is determined solely based on structural layout without considering the influence of temperature distribution. By determining the opening layer position based on temperature data and configuring different opening diameters according to a set aperture ratio, and determining the corresponding number of openings based on core casing structural data, the core casing opening parameters can be matched and adjusted according to actual thermal conditions and structural requirements. This solves the problems of traditional uniform aperture and fixed aperture design. The invention addresses the issue of unreasonable local flow distribution caused by the number of orifices. By calculating the natural circulation driving head and orifice flow resistance corresponding to the updated casing structure, the designed casing structure can meet the matching relationship between the fluid flow driving force and the orifice drainage resistance. This ensures the drainage capacity of the casing while effectively suppressing the temperature gradient in the gas space and improving temperature uniformity. This invention does not add any independent structures or change the original function of the casing. It only extends the casing above the fluid surface and correspondingly sets through holes for gas flow, allowing the fluid in the gas phase space to achieve more complete natural circulation. It has good adaptive characteristics, and the greater the temperature difference, the stronger the suppression effect.

[0025] 2. This invention proposes an open core casing and its design method, design device, and storage medium. By setting a deflection angle that is inclined to the radius of the casing for some of the openings, the opening direction is changed from the traditional radial straight hole structure to an inclined opening structure with a certain flow guiding effect. This can adjust the flow direction of the fluid when passing through the openings, improve the fluid exchange process inside and outside the casing, and the inclined openings can generate swirling flow of the gas entering tangentially, enhance the mixing effect, increase the residence time of the gas in the casing, improve the heat exchange efficiency, and help to destroy the possible local thermal stratification "dead zone".

[0026] 3. This invention proposes an open core shroud and its design method, design device, and storage medium. This invention establishes a three-dimensional fluid simulation model based on pressure vessel structural data and shroud structural data, and obtains the temperature field by combining inlet flow rate, inlet temperature, pressure boundary, and core heat source distribution parameters. Furthermore, it determines the location and range of the open layer based on the maximum temperature gradient, so that the open position can correspond to the internal thermal state of the reactor, avoiding the problem of insufficient consideration of thermal characteristics caused by determining the open position based only on structural layout or experience in the prior art.

[0027] 4. This invention proposes an open core casing and its design method, design device, and storage medium. By gradient setting of the opening diameter of different open layers according to the aperture ratio, and determining the number of openings in each layer according to the casing diameter and the opening diameter, verification parameters such as gas density difference, effective natural circulation height, flow velocity and density at the opening are obtained based on the reconstructed three-dimensional fluid simulation model. The natural circulation driving head and the opening flow resistance are calculated respectively. When the conditions are not met, the position of the opening layer, the opening diameter, or the number of openings are iteratively adjusted so that the final casing structure can meet the design condition that the natural circulation driving head is greater than the opening flow resistance, thereby improving the accuracy of the casing opening parameter design and its adaptability to the natural circulation operation state. Attached Figure Description

[0028] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A flowchart of an embodiment of a perforated core shroud design method is shown; Figure 2 A schematic diagram of the structure of an open core shroud according to one embodiment is shown; Figure 3 A schematic diagram of an open core shroud design device according to one embodiment is shown; Figure 4 A schematic diagram of the structure of an open core casing design product according to one embodiment is shown; Figure 5 A schematic diagram of the structure of an electronic device according to an embodiment is shown.

[0029] The above figures include the following reference numerals: 1. Pressure vessel; 2. Enclosure; 3. Opening. Detailed Implementation

[0030] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] The present invention will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed by the present invention.

[0032] Example

[0033] To address the challenge of collaboratively designing the parameters for core shroud openings based on reactor thermal-hydraulic characteristics to meet natural circulation performance and transient flow resistance control requirements, this invention proposes a perforated core shroud, along with its design method, design apparatus, and storage medium.

[0034] The embodiments of this application will be described in detail below with reference to the accompanying drawings and examples.

[0035] It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0036] To achieve the above objectives, the present invention also proposes a design method for an open core casing.

[0037] In this invention, the CFD simulation software refers to software tools used for numerical simulation of fluid flow, heat transfer, and mass transfer processes based on Computational Fluid Dynamics (CFD) methods, such as ANSYS Fluent and STAR-CCM+. Using this CFD simulation software, a fluid simulation model can be established based on input structural parameters, fluid medium parameters, and boundary conditions, and simulation data such as flow field, temperature field, pressure field, velocity field, and density distribution can be obtained.

[0038] like Figure 1 The figure illustrates a design method for an open core casing according to an embodiment of the present invention. The process mainly includes the following steps: S101: Collect pressure vessel structural data and casing structural data.

[0039] Furthermore, collection such as Figure 2The pressure vessel shown in the figure has pressure vessel structure data and casing structure data. The pressure vessel structure data includes the pressure vessel size and structural composition, and the casing structure data includes the casing size and structural composition.

[0040] S102: Based on the pressure vessel structure data and the casing structure data, perform CFD data simulation to determine the temperature data under typical operating conditions. The temperature data includes temperature distribution and temperature gradient.

[0041] Further, the pressure vessel structure data and the shroud structure data collected in step S101 are input into CFD simulation software to construct a structural model. Then, by setting cooling medium parameters, a three-dimensional fluid simulation model is constructed by adding the structural model. Boundary conditions corresponding to the typical working conditions are set, including inlet flow rate, inlet temperature, pressure boundary, and core heat source distribution parameters. The temperature field is obtained by performing data simulation on the three-dimensional fluid simulation model using the CFD simulation software. In this embodiment, ANSYS Fluent is selected as the CFD simulation software to perform data simulation on the three-dimensional fluid simulation model. The temperature distribution corresponding to the axial direction of the shroud is extracted according to the temperature field, and the temperature gradient is calculated according to the temperature distribution.

[0042] Specifically, in this embodiment, the rated operating condition of an integrated natural circulation reactor is taken as the typical operating condition. A three-dimensional fluid simulation model of the pressure vessel and shroud is established using ANSYS Fluent. Light water is selected as the cooling medium, and the cooling medium parameters include a medium density of 776 kg / m³, a specific heat capacity of 5.0 kJ / (kg·K), an inlet flow rate of 900 kg / s, an inlet temperature of 273.1℃, a pressure boundary of 15.5 MPa, a core thermal power of 200 MW, and an axial cosine distribution for the core heat source. A pressure-based steady-state solver is used, the turbulence model is the Realizable k-ε model, the pressure-velocity coupling algorithm is the SIMPLE algorithm, and the residual convergence accuracy is set to 1×10⁻⁶. -5 After simulation, the internal temperature field of the pressure vessel was obtained. A temperature sampling point was extracted every 50 mm along the axial direction of the casing, resulting in a total of 24 temperature sampling points. Among them, the temperature at the bottom of the gas space was 315.8℃, and the temperature at the top was 292.4℃. The maximum axial temperature gradient of the gas space appeared at a position about 0.95 m above the liquid level, corresponding to a temperature gradient of about 9.6℃ / m. Based on the temperature data of each sampling point, the axial temperature distribution of the casing and the corresponding temperature gradient were calculated, and the position corresponding to the maximum temperature gradient was used as the basis for subsequently determining the location of the opening layer.

[0043] S103: Determine the location of the perforated layer based on the temperature data; set the aperture ratio, set the opening diameter of different holes based on the aperture ratio, and determine the number of openings based on the surrounding cylinder structure data and the opening diameter.

[0044] Furthermore, the position of the opening layer includes an upper limit and a lower limit, which are used to define the positions of the highest and lowest layers of the opening layer, respectively. The expressions for the upper and lower limits are as follows: , , in, The lower limit is the position mentioned above. The upper limit bit, The height corresponding to the maximum value in the temperature gradient. For positional weights, For example Figure 2 The total height of the gas phase space shown refers to the space within the pressure vessel that is above the coolant surface and not filled with liquid coolant. It contains water vapor and non-condensable gases, which together form a vapor-gas mixing space. The pressure of the primary loop system is maintained by the partial pressure of water vapor and the partial pressure of non-condensable gases.

[0045] Specifically, position weight The value range is 0.15-0.3, and in this embodiment, the position weight is 0.2. The height corresponding to the maximum value of the temperature gradient obtained from the simulation experiment in step S102 above, and the total height of the gas phase space is 1.5m, therefore the lower limit is... Upper limit .

[0046] Furthermore, the aperture ratio is the ratio of the maximum and minimum aperture diameters. Multiple apertures are arranged in layers along the axial direction of the casing to form an aperture layer. The aperture diameter of each layer decreases uniformly from the bottom to the top of the casing according to a preset gradient, so that the maximum aperture diameter and the minimum aperture diameter satisfy the aperture ratio.

[0047] Furthermore, the aperture ratio can be in the range of 1.3-1.6. In this embodiment, the aperture ratio is 1.5, so the ratio of the opening diameter at the upper limit position to the opening diameter at the lower limit position is 1.5. Furthermore, a temperature difference threshold between adjacent perforated layers is preset, and the number of perforated layers is set according to the temperature difference threshold.

[0048] Furthermore, the preset temperature difference threshold between adjacent perforated layers can be 2℃, 3℃, or 4℃. Based on the temperature distribution obtained in step S102, the perforated area is searched from bottom to top. When the temperature difference between adjacent positions reaches the temperature difference threshold, the position of the next perforation layer is determined. The above process is repeated in sequence, and finally the number of perforated layers is determined within the range of 0.65m-1.25m. The position of each perforation layer is obtained by dividing the difference between the upper and lower limits by the number of perforated layers.

[0049] Specifically, in this embodiment, the preset temperature difference threshold between adjacent perforated layers is 3℃. Based on the axial temperature distribution of the casing obtained in step S102, temperature statistics are performed at each height position within the perforation area. The temperatures corresponding to 0.65m, 0.85m, 1.05m, and 1.25m are approximately 308.5℃, 305.1℃, 301.6℃, and 298.2℃, respectively. The temperature differences between adjacent height positions are 3.4℃, 3.5℃, and 3.4℃, respectively, all of which are greater than the temperature difference threshold. Therefore, it is determined that four layers of perforations are to be set within the perforation area.

[0050] Furthermore, the number of openings is determined based on the cylindrical structure data and the opening diameter, and its expression is as follows: ,in The number of openings corresponding to each layer, Where d is the diameter of the cylindrical structure in the cylindrical structure data, and d is the diameter of the opening corresponding to that layer. For diameter weights.

[0051] Specifically, based on the structural data of the casing, the casing diameter D is 2.40m, and the diameter weight β can be 1.5-2.0. In this embodiment, 1.8 is used. Based on empirical values, the aperture ratios obtained in the above steps are used to assign values ​​to the aperture diameters corresponding to the four aperture layers. The aperture layer located at the lower limit along the casing axis corresponds to an aperture diameter of 40mm, and the aperture layer located at the upper limit corresponds to an aperture diameter of 60mm. The aperture diameter of each layer decreases uniformly from the bottom to the top of the casing along a preset gradient. Therefore, the difference between adjacent diameters is small. Therefore, the corresponding opening diameters of the two middle layers are 53.33mm and 46.67mm, respectively.

[0052] According to the formula The number of openings in each layer is calculated. The number of openings in the layer with a diameter of 60mm is rounded up to 70, the number of openings in the layer with a diameter of 53.33mm is rounded up to 79, the number of openings in the layer with a diameter of 46.67mm is rounded up to 90, and the number of openings in the layer with a diameter of 40mm is rounded up to 105. The different openings in each layer are evenly distributed along the circumference of the cylinder.

[0053] Furthermore, the circumferential direction of some openings is set with a deflection angle that is inclined to the radius direction of the surrounding tube, and the deflection angle ranges from 15° to 30°.

[0054] Furthermore, in this embodiment, to improve the flow state of fluids inside and outside the casing when passing through the openings, the opening direction of some of the openings is adjusted so that the central axis of some of the openings forms an inclination angle with the radial direction of the casing. Specifically, some of the openings are configured as deflection hole structures, wherein the deflection angle ranges from 15° to 30°.

[0055] Preferably, the deflection angle is selected as 20°, that is, the central axis of some openings is deflected 20° circumferentially relative to the radius direction of the surrounding tube, while the remaining openings still adopt the straight hole structure arranged along the radius direction of the surrounding tube.

[0056] Specifically, in this embodiment, taking a perforated layer with 70 openings as an example, 20 of the openings are set as deflection holes, and the remaining 50 openings are set as straight holes. The deflection holes are arranged at intervals along the circumference of the casing, so that the circumference of the casing has fluid exchange channels in different directions. Through the above arrangement, some fluid generates a certain circumferential flow component when passing through the openings of the casing, thereby matching the flow direction of the fluid inside the casing.

[0057] S104: Add the opening layer position, opening diameter and opening number to the surrounding structure data, calculate the natural circulation drive head and opening flow resistance corresponding to the updated surrounding structure data, and save the updated surrounding structure data if the natural circulation drive head is greater than the opening flow resistance.

[0058] Further, the cylindrical structure data is modified and a three-dimensional fluid simulation model is reconstructed based on the location of the opening layer, the diameter of the opening, and the number of openings. Verification parameters are obtained from the three-dimensional fluid simulation model, including gas density difference, effective natural circulation height, gas velocity at the opening, and gas density at the opening. Data simulation is performed based on the three-dimensional fluid simulation model to obtain the gas density difference between adjacent regions. The effective natural circulation height is calculated based on the difference between the upper and lower limits of the opening layer. The gas velocity and gas density simulated at different opening locations in the three-dimensional fluid simulation model are extracted. The natural circulation driving head and the flow resistance at the opening are calculated based on the verification parameters, and their expressions are as follows: , , in The natural circulation drive head, The gas density difference; This is the acceleration due to gravity; such as Figure 2 As shown The effective height of the natural circulation is defined as the natural circulation of gas. The flow resistance of the opening, The drag coefficient is the aperture diameter. The gas density at the opening is [the specified value]. The gas flow rate at the opening is described.

[0059] Specifically, in this embodiment, the cylindrical structure data is modified based on the determined location, diameter, and number of openings, and a new three-dimensional fluid simulation model is constructed. Data simulation is performed using this three-dimensional fluid simulation model to obtain the gas density distribution at adjacent locations above and below the opening area. Specifically, the gas density in the upper region of the opening layer is 78.9 kg / m³, and the gas density in the lower region of the opening layer is 76.3 kg / m³. Therefore, the gas density difference between adjacent regions is: , Calculate the effective height of natural circulation based on the upper and lower limits of the opening layer location: , The gas velocity and gas density of the grid regions corresponding to different opening positions are extracted using the three-dimensional fluid simulation model. In this embodiment, the average opening flow state is used as the calculation parameter, and the average gas velocity at the opening is obtained as 0.5 m / s, the average gas density at the opening is 77.6 kg / m³, the drag coefficient K corresponding to the opening diameter is taken as 1.2, and the pressure head is calculated according to the natural circulation driving head calculation formula, where g is taken as 9.8. , Substitute the parameters into the formula for calculating the flow resistance at the orifice: , At this point, the natural circulation driving head is greater than the flow resistance of the opening, so natural circulation can be formed, and the updated shroud structure data can be saved as the design parameters of the opening core shroud.

[0060] Furthermore, if the natural circulation driving head is less than the orifice flow resistance, the position of the orifice layer, the orifice diameter, or the number of orifices is adjusted, and the above calculation process is repeated to iterate the cylindrical structure data until the natural circulation driving head is greater than the orifice flow resistance.

[0061] Based on another aspect of the embodiments of this application, the present invention also provides an open-pore core shroud, such as... Figure 2 As shown in the figure, the casing 2 is located inside the pressure vessel 1. Preferably, the casing is provided with openings corresponding to the opening layer position, opening diameter deflection angle and opening number of the opening layer obtained according to the above-mentioned opening core casing design method.

[0062] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0063] Based on another aspect of the embodiments of this application, the present invention also provides a design device for an open-hole core casing. For example... Figure 3 As shown, the device includes: The data acquisition module 301 is used to acquire pressure vessel structural data and cofferdam structural data. The construction module 302 is used to perform CFD data simulation based on the pressure vessel structure data and the casing structure data to determine the temperature data under typical working conditions. The temperature data includes temperature distribution and temperature gradient. The parameter module 303 is used to determine the position of the opening layer based on the temperature data; set the aperture ratio; set the opening diameter of different holes based on the aperture ratio; and determine the number of openings based on the surrounding cylinder structure data and the opening diameter. The verification module 304 is used to add the opening layer position, the opening diameter and the number of openings to the surrounding structure data, calculate the natural circulation driving head and the opening flow resistance corresponding to the updated surrounding structure data, and save the updated surrounding structure data if the natural circulation driving head is greater than the opening flow resistance.

[0064] As an optional solution, the above-mentioned device is also used to: further include: setting a deflection angle of the circumferential direction of a portion of the opening inclined with respect to the radial direction of the surrounding cylinder, the deflection angle being in the range of 15°-30°.

[0065] As an optional solution, the above-mentioned device is also used to: determine temperature data under typical operating conditions by performing CFD data simulation based on the pressure vessel structure data and the shroud structure data, including: inputting the pressure vessel structure data and the shroud structure data into CFD simulation software, setting cooling medium parameters to construct a three-dimensional fluid simulation model, setting boundary conditions corresponding to the typical operating conditions, the boundary conditions including inlet flow rate, inlet temperature, pressure boundary and core heat source distribution parameters, performing data simulation on the three-dimensional fluid simulation model through the CFD simulation software to obtain a temperature field, extracting the temperature distribution corresponding to the axial direction of the shroud based on the temperature field, and calculating the temperature gradient based on the temperature distribution.

[0066] As an optional solution, the above-mentioned device is also used to: determine the position of the opening layer based on the temperature data, including: extracting the height corresponding to the maximum value in the temperature gradient to calculate the upper and lower limits of the opening.

[0067] As an optional solution, the above-mentioned device is also used for: the expressions for the upper limit and lower limit are as follows: , ,in, The lower limit is the position mentioned above. The upper limit bit, The height corresponding to the maximum value in the temperature gradient. For positional weights, This represents the total height of the gas phase space.

[0068] As an optional solution, the above-mentioned device is also used to: set the opening diameter of different holes according to the aperture ratio, including: the aperture ratio is the ratio of the maximum value and the minimum value of the opening diameter, multiple openings are arranged in layers along the axial direction of the surrounding cylinder to form an opening layer, the opening diameter of each layer decreases uniformly from the bottom to the top of the surrounding cylinder according to a preset gradient, so that the maximum opening diameter and the minimum opening diameter satisfy the aperture ratio, the opening diameter corresponding to the opening layer located at the upper limit and the lower limit is preset according to empirical values, and the opening diameter corresponding to other opening layers is set accordingly.

[0069] As an optional solution, the above-mentioned device is also used to: further include: preset a temperature difference threshold between adjacent perforated layers, and set the number of perforated layers according to the temperature difference threshold.

[0070] As an optional solution, the above-mentioned device is also used to: determine the number of openings based on the cylindrical structure data and the opening diameter, as expressed below: ,in The number of openings corresponding to each layer, Where d is the diameter of the cylindrical structure in the cylindrical structure data, and d is the diameter of the opening corresponding to that layer. For diameter weights.

[0071] As an optional solution, the above-mentioned device is also used to: calculate the natural circulation driving head and orifice flow resistance corresponding to the updated cylindrical structure data, including: modifying the cylindrical structure data and reconstructing the three-dimensional fluid simulation model according to the orifice layer position, the orifice diameter and the number of orifices, obtaining verification parameters according to the three-dimensional fluid simulation model, the verification parameters including gas density difference, effective natural circulation height, gas velocity at the orifice and gas density at the orifice, and calculating the natural circulation driving head and the orifice flow resistance according to the verification parameters.

[0072] As an optional solution, the above-mentioned device is also used to: obtain verification parameters based on the three-dimensional fluid simulation model, including: obtaining the gas density difference between adjacent regions by performing data simulation based on the three-dimensional fluid simulation model, calculating the effective height of natural circulation based on the difference between the upper limit and the lower limit in the position of the opening layer, and extracting the gas velocity and gas density of the grid simulation corresponding to different openings in the three-dimensional fluid simulation model.

[0073] As an optional solution, the above-mentioned device is also used to: calculate the natural circulation drive head and the orifice flow resistance based on verification parameters, including: , ,in The natural circulation drive head, The gas density difference; It is the acceleration due to gravity; The effective height of the natural circulation; The flow resistance of the opening, The drag coefficient is the aperture diameter. The gas density at the opening is [the specified value]. The gas flow rate at the opening is described.

[0074] As an optional solution, the above-mentioned device is further used to: further include: if the natural circulation driving pressure head is less than the opening flow resistance, then adjust the position of the opening layer, the opening diameter or the number of openings, and repeat the above calculation process to iterate the cylindrical structure data until the natural circulation driving pressure head is greater than the opening flow resistance.

[0075] In this application embodiment, the terms "module" or "unit" refer to a computer program or part of a computer program that has a predetermined function and works with other related parts to achieve a predetermined goal, and can be implemented wholly or partially using software, hardware (such as processing circuitry or memory), or a combination thereof. Similarly, a processor (or multiple processors or memory) can be used to implement one or more modules or units. Furthermore, each module or unit can be part of an overall module or unit that includes the functionality of that module or unit.

[0076] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0077] According to one aspect of this application, a computer program product is provided, the computer program product comprising a computer program.

[0078] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0079] Figure 4 A schematic block diagram of a computer system architecture for implementing an electronic device according to embodiments of the present application is shown.

[0080] It should be noted that, Figure 4 The computer system 400 of the electronic device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0081] like Figure 4 As shown, the computer system 400 includes a central processing unit (CPU) 401, which is coupled to a read-only memory (ROM) 402. The CPU 401 can perform various appropriate actions and processes based on programs stored in the ROM or loaded from storage section 408 into random access memory (RAM). The RAM also stores various programs and data required for system operation. The CPU 401, ROM 402, and RAM 403 are interconnected via a bus 404. An input / output interface 405 (I / O interface) is also connected to the bus 404.

[0082] The following components are connected to the input / output interface 405: Input section 406, including but not limited to one or more of the following: keyboard, mouse, touch screen, touchpad, buttons, microphone, camera, biometric device, and various sensors; Output section 407, including but not limited to one or more of the following: display (e.g., liquid crystal display (LCD), organic light-emitting diode display (OLED), mini-LED display, micro-LED display, e-ink screen, head-up display (HUD), etc.), speaker, buzzer, indicator light, vibration device, etc.); Storage section 408, including but not limited to hard disk, solid-state drive, flash memory, etc. (the specific types can be found in the relevant description of memory in this application); and Communication section 409, including one or more of the following: wired communication modules (e.g., local area network (LAN) card, modem, Ethernet interface, CAN bus interface, USB interface, serial interface, etc.) and / or wireless communication modules (e.g., Wi-Fi module, Bluetooth module, Zigbee module, LoRa module, 4G / 5G communication module, NB-IoT module, etc.). The communication unit 409 performs communication processing via networks such as the Internet, local area network, wide area network, and vehicle networks (such as CAN bus, vehicle Ethernet). The driver 410 can also be connected to the input / output interface 405 as needed. Removable media 411, such as disks, optical disks, magneto-optical disks, semiconductor memory, USB flash drives, memory cards (such as SD cards, TF cards), etc., can be installed on the driver 410 as needed so that computer programs read from them can be installed into the storage unit 408 as required.

[0083] Specifically, according to embodiments of this application, the processes described in the various method flowcharts can be implemented as computer software programs. For example, embodiments of this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 409, and / or installed from removable medium 411. When the computer program is executed by central processing unit 401, it performs various functions defined in the system of this application.

[0084] According to another aspect of the embodiments of this application, an electronic device for a method of designing an open-aperture core shroud is also provided. This embodiment uses this electronic device as an example of a terminal device for illustration. Figure 5As shown, the electronic device includes a memory 502 and a processor 504. The memory 502 stores a computer program, and the processor 504 is configured to execute the steps of any of the above method embodiments through the computer program.

[0085] Optionally, in this embodiment, the aforementioned electronic device may be located in at least one of a plurality of network devices in a computer network.

[0086] Optionally, in this embodiment, the processor may be configured to execute the methods in the embodiments of this application via a computer program.

[0087] Alternatively, as those skilled in the art will understand, Figure 5 The structure shown is for illustrative purposes only. Figure 5 This does not limit the structure of the aforementioned electronic devices. For example, the electronic device may also include components that are more... Figure 5 The more or fewer components shown (such as network interfaces, etc.), or having the same Figure 5 The different configurations shown.

[0088] The memory 502 can be used to store software programs and modules, such as the program instructions / modules corresponding to the perforated core shroud design method and apparatus in this embodiment. The processor 504 is coupled to the memory 502, and by running the software programs and modules stored in the memory 502, various functional applications and data processing are executed, thereby realizing the aforementioned perforated core shroud design method. In some instances, the memory 502 may further include a memory remotely located relative to the processor 504, and these remote memories can be connected to a terminal via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof. Specifically, the memory 502 may be used, but is not limited to, to store collected pressure vessel structure data and shroud structure data. As an example, such as... Figure 5 As shown, the memory 502 may include, but is not limited to, the acquisition module 301, construction module 302, parameter module 303, and verification module 304 in the aforementioned perforated core casing design device. Furthermore, it may include, but is not limited to, other module units in the aforementioned device, which will not be elaborated upon in this example.

[0089] Optionally, the transmission device 506 described above is used to receive or send data via a network. Specific examples of the network described above may include wired networks and wireless networks. In one example, the transmission device 506 includes a Network Interface Controller (NIC), which can be connected to other network devices and routers via a network cable to communicate with the Internet or a local area network. In another example, the transmission device 506 is a Radio Frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0090] In addition, the aforementioned electronic device also includes: a display 508 for displaying the pressure vessel structure data and the casing structure data; and a connection bus 510 for connecting the various module components in the aforementioned electronic device.

[0091] In the embodiments of this application, the processor can be any hardware unit with data processing and instruction execution capabilities, including but not limited to a central processing unit (CPU), microprocessor, microcontroller unit (MCU), digital signal processor (DSP), graphics processing unit (GPU), neural processing unit (NPU), tensor processing unit (TPU), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), complex programmable logic device (CPLD), system-on-chip (SoC), microcontroller, or any combination of the above devices. The processor can be a single-core processor or a multi-core processor; it can be integrated into a single chip or distributed across multiple chips or multiple physical devices.

[0092] In embodiments of this application, the memory may include random access memory (RAM), such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), etc. The memory may also include non-volatile memory, such as read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory (including but not limited to NAND Flash, NOR Flash), solid-state drive (SSD), embedded multimedia card (eMMC), universal flash storage (UFS), magnetic storage devices (such as hard disks), ferroelectric memory (FRAM), magnetoresistive memory (MRAM), phase-change memory (PCM), resistive random access memory (ReRAM), or one or more other non-volatile solid-state storage media.

[0093] In this application, "memory," "computer-readable storage medium," and "computer-readable medium" refer to the same or related concepts and can be used interchangeably. Specifically, when the aforementioned types of memory are used to store computer program instructions and / or data, they constitute the computer-readable storage medium as referred to in this application; conversely, the physical implementation of the computer-readable storage medium as referred to in this application can be any one or more of the aforementioned types of memory. Those skilled in the art should understand that the computer-readable storage medium can be a single medium or a distributed medium (e.g., a combination of storage media distributed across multiple physical devices or multiple chips).

[0094] In this application, the computer-readable storage medium is a non-transitory computer-readable storage medium, which refers to a physical storage device capable of storing information in a non-transitory manner. This includes, but is not limited to, various types of random access memory, read-only memory, flash memory, solid-state drives, magnetic storage devices, and other storage media with physical form, but excludes transiently propagating signals themselves (such as electromagnetic carrier waves, modulation signals, etc.). Those skilled in the art should understand that "non-transitory" here means that the storage medium has a persistent physical form relative to transiently propagating signals, and does not limit the storage medium to be non-volatile memory; although the aforementioned types of random access memory are volatile memories, they still fall under the category of non-transitory computer-readable storage media as defined in this application.

[0095] According to one aspect of this application, a computer-readable storage medium is provided, wherein a processor of an electronic device reads computer instructions from the computer-readable storage medium, and executes the computer instructions, causing the electronic device to perform an open-hole core shroud design method provided in one of the various alternative implementations of the above-described open-hole core shroud design.

[0096] Optionally, in this embodiment, the computer-readable storage medium described above may be configured to store methods for performing the embodiments of this application.

[0097] Optionally, in this embodiment, those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing the hardware related to the terminal device, and the program can be stored in a computer-readable storage medium.

[0098] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0099] If the integrated units in the above embodiments are implemented as software functional units and sold or used as independent products, they can be stored in the aforementioned computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause one or more electronic devices to execute all or part of the steps of the methods described in the various embodiments of this application.

[0100] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0101] In the several embodiments provided in this application, it should be understood that the disclosed application can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces; indirect couplings or communication connections between units or modules may be electrical or other forms.

[0102] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0103] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0104] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0105] In summary, as can be seen from the above description, the embodiments of the present invention achieve the following technical effects: 1. This invention proposes an open-aperture core casing, its design method, design device, and storage medium. By using CFD simulations of pressure vessel and core casing structure data, temperature data under typical operating conditions is obtained, enabling the characterization of the differences in circumferential and axial thermal properties of the core casing. This avoids the problem in existing technologies where the opening position is determined solely based on structural arrangement without considering the influence of temperature distribution. By determining the opening layer position based on temperature data and configuring different opening diameters according to a set aperture ratio, and determining the corresponding number of openings based on core casing structure data, the core casing opening parameters can be matched and adjusted according to actual thermal conditions and structural conditions. This solves the problem of unreasonable local flow distribution caused by traditional uniform aperture and fixed number of openings. By calculating the natural circulation drive head and opening flow resistance corresponding to the updated core casing structure, the designed core casing structure can meet the matching relationship between fluid flow drive force and opening drainage resistance. This effectively suppresses the temperature gradient in the gas space and improves temperature uniformity while ensuring the core casing's drainage capacity. This invention does not add any independent structure, does not change the original function of the core casing, and has good adaptive characteristics; the greater the temperature difference, the stronger the suppression effect.

[0106] 2. This invention proposes an open core casing and its design method, design device, and storage medium. By setting a deflection angle that is inclined to the radius of the casing for some of the openings, the opening direction is changed from the traditional radial straight hole structure to an inclined opening structure with a certain flow guiding effect. This can adjust the flow direction of the fluid when passing through the openings, improve the fluid exchange process inside and outside the casing, and the inclined openings can generate swirling flow of the gas entering tangentially, enhance the mixing effect, increase the residence time of the gas in the casing, improve the heat exchange efficiency, and help to destroy the possible local thermal stratification "dead zone".

[0107] 3. This invention proposes an open core shroud and its design method, design device, and storage medium. This invention establishes a three-dimensional fluid simulation model based on pressure vessel structural data and shroud structural data, and obtains the temperature field by combining inlet flow rate, inlet temperature, pressure boundary, and core heat source distribution parameters. Furthermore, it determines the location and range of the open layer based on the maximum temperature gradient, so that the open position can correspond to the internal thermal state of the reactor, avoiding the problem of insufficient consideration of thermal characteristics caused by determining the open position based only on structural layout or experience in the prior art.

[0108] 4. This invention proposes an open core casing and its design method, design device, and storage medium. By gradient setting of the opening diameter of different open layers according to the aperture ratio, and determining the number of openings in each layer according to the casing diameter and the opening diameter, verification parameters such as gas density difference, effective natural circulation height, flow velocity and density at the opening are obtained based on the reconstructed three-dimensional fluid simulation model. The natural circulation driving head and the opening flow resistance are calculated respectively. When the conditions are not met, the position of the opening layer, the opening diameter, or the number of openings are iteratively adjusted so that the final casing structure can meet the design condition that the natural circulation driving head is greater than the opening flow resistance, thereby improving the accuracy of the casing opening parameter design and its adaptability to the natural circulation operation state.

[0109] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0110] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0111] It should be noted that, in the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

Claims

1. A method for designing an open core casing, characterized in that, include: Collect structural data of the pressure vessel and its casing; Based on the pressure vessel structure data and the casing structure data, CFD data simulation is performed to determine the temperature data under typical operating conditions. The temperature data includes temperature distribution and temperature gradient. The location of the perforated layer is determined based on the temperature data; Set the aperture ratio, set the opening diameter of different holes according to the aperture ratio, and determine the number of openings according to the surrounding cylinder structure data and the opening diameter; The data is added to the cylindrical structure data based on the location of the perforation layer, the diameter of the perforation, and the number of perforations. The natural circulation drive head and the flow resistance of the perforation are calculated for the updated cylindrical structure data. If the natural circulation drive head is greater than the flow resistance of the perforation, the updated cylindrical structure data is saved.

2. The method according to claim 1, characterized in that, Also includes: The circumferential direction of some openings is set with a deflection angle that is inclined to the radius direction of the surrounding tube, and the deflection angle ranges from 15° to 30°.

3. The method according to claim 1, characterized in that, Based on the pressure vessel structural data and the casing structural data, CFD data simulations are performed to determine temperature data under typical operating conditions, including: The pressure vessel structure data and the shroud structure data are input into CFD simulation software. Cooling medium parameters are set to construct a three-dimensional fluid simulation model. Boundary conditions corresponding to the typical operating conditions are set. The boundary conditions include inlet flow rate, inlet temperature, pressure boundary, and core heat source distribution parameters. The temperature field is obtained by simulating the three-dimensional fluid simulation model using the CFD simulation software. The temperature distribution corresponding to the axial direction of the shroud is extracted based on the temperature field. The temperature gradient is calculated based on the temperature distribution.

4. The method according to claim 1, characterized in that, Determining the location of the opening layer based on the temperature data includes: Extract the height corresponding to the maximum value in the temperature gradient to calculate the upper and lower limits of the opening.

5. The method according to claim 4, characterized in that, The expressions for the upper and lower limits are as follows: ， ， in, The lower limit position, The upper limit bit, The height corresponding to the maximum value in the temperature gradient. For positional weights, This represents the total height of the gas phase space.

6. The method according to claim 4, characterized in that, The aperture diameter of different holes is set according to the aperture ratio, including: The aperture ratio is the ratio of the maximum and minimum aperture diameters. Multiple apertures are arranged in layers along the axial direction of the casing to form an aperture layer. The aperture diameter of each layer decreases uniformly from bottom to top along the axial direction of the casing according to a preset gradient, so that the maximum aperture diameter and the minimum aperture diameter satisfy the aperture ratio. The aperture diameters corresponding to the aperture layers located at the upper and lower limits are preset according to empirical values, and the aperture diameters corresponding to other aperture layers are set accordingly.

7. The method according to claim 6, characterized in that, Also includes: A temperature difference threshold between adjacent perforated layers is preset, and the number of perforated layers is set according to the temperature difference threshold.

8. The method according to claim 1, characterized in that, The number of openings is determined based on the cylindrical structure data and the opening diameter, and the expression is as follows: ， in The number of openings corresponding to each layer, Where d is the diameter of the cylindrical structure in the cylindrical structure data, and d is the diameter of the opening corresponding to that layer. For diameter weights.

9. The method according to claim 4, characterized in that, The calculation of the natural circulation drive head and orifice flow resistance corresponding to the updated cylindrical structure data includes: The data of the surrounding cylinder structure are modified according to the location of the opening layer, the diameter of the opening, and the number of openings, and a three-dimensional fluid simulation model is reconstructed. Verification parameters are obtained based on the three-dimensional fluid simulation model. The verification parameters include gas density difference, effective height of natural circulation, gas velocity at the opening, and gas density at the opening. The natural circulation driving head and the flow resistance of the opening are calculated based on the verification parameters.

10. The method according to claim 9, characterized in that, The verification parameters obtained from the three-dimensional fluid simulation model include: The gas density difference between adjacent regions is obtained by data simulation based on the three-dimensional fluid simulation model. The effective height of natural circulation is calculated based on the difference between the upper limit and the lower limit of the opening layer. The gas velocity and gas density of the corresponding mesh simulation at different openings in the three-dimensional fluid simulation model are extracted.

11. The method according to claim 9, characterized in that, The calculation of the natural circulation drive head and the orifice flow resistance based on the verification parameters includes: ， ， in The natural circulation drive head, The gas density difference; It is the acceleration due to gravity; The effective height of the natural circulation; The flow resistance of the opening, The drag coefficient is the aperture diameter. The gas density at the opening is [the specified value]. The gas flow rate at the opening is described.

12. The method according to claim 1, characterized in that, Also includes: If the natural circulation driving head is less than the orifice flow resistance, then adjust the orifice layer position, the orifice diameter, or the number of orifices, and repeat the above calculation process to iterate the cylindrical structure data until the natural circulation driving head is greater than the orifice flow resistance.

13. A perforated core casing design device, characterized in that, include: The data acquisition module is used to acquire structural data of the pressure vessel and the surrounding structure data. A construction module is used to perform CFD data simulation based on the pressure vessel structure data and the casing structure data to determine temperature data under typical working conditions, wherein the temperature data includes temperature distribution and temperature gradient. The parameter module is used to determine the location of the opening layer based on the temperature data; Set the aperture ratio, set the opening diameter of different holes according to the aperture ratio, and determine the number of openings according to the surrounding cylinder structure data and the opening diameter; The verification module is used to add the opening layer position, the opening diameter and the number of openings to the cylindrical structure data, calculate the natural circulation driving head and the opening flow resistance corresponding to the updated cylindrical structure data, and save the updated cylindrical structure data if the natural circulation driving head is greater than the opening flow resistance.

14. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored computer program, wherein the computer program, when executed by an electronic device, performs the method according to any one of claims 1 to 12.

15. A computer program product, comprising a computer program, characterized in that, When executed by a processor, the computer program implements the steps of the method according to any one of claims 1 to 12.

16. An electronic device comprising a memory and a processor, characterized in that, The memory stores a computer program, and the processor is configured to execute the method according to any one of claims 1 to 12 through the computer program.

17. A perforated core casing, characterized in that, The core shroud includes multiple perforated layers arranged in layers along the axial direction, and each perforated layer includes multiple circumferentially distributed openings; the position of the perforated layers, the diameter of the openings and the number of openings are determined according to the perforated core shroud design method according to any one of claims 1 to 12.

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