Conduction-cooled superconductor cryogenic container and its honeycomb heat transfer structure design method

Abstract

The present invention provides a conduction-cooled superconductor type cryogenic container and a design method for its honeycomb heat transfer structure, which relates to the field of high-temperature superconducting magnetic levitation technology and includes: a refrigerator and a cryogenic container. The refrigerator includes a cold head heat conduction column; the cryogenic container includes an outer cavity, superconducting bulk materials, a copper box, and a honeycomb support heat transfer structure. The outer cavity includes a cover plate and a rectangular cavity that are fixedly connected to each other. The refrigerator is fixedly arranged on the side of the outer cavity. The cover plate is fixedly connected to the bottom of the vehicle body of the maglev train. The copper box is fixedly arranged at the bottom of the rectangular cavity. The superconducting bulk materials are fixedly arranged inside the copper box. The cold head heat conduction column passes through a through hole in the side wall of the outer cavity and is fixedly connected to the copper box. The honeycomb support heat transfer structure is arranged between the copper box and the cover plate. By analyzing the heat conduction path and stress concentration conditions, the present invention comprehensively optimizes the size, wall thickness, and distribution of stiffeners of the honeycomb unit, effectively reducing the heat conduction efficiency and ensuring the long-term stability and reliability of the cryogenic container.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature superconducting maglev technology. Specifically, it relates to a conduction-cooled superconductor cryogenic container and a design method for its honeycomb heat transfer structure. Background Art

[0002] The conduction-cooled superconductor cryogenic container plays a crucial role in high-temperature superconducting maglev trains. Its main function is to ensure the efficient operation of superconducting bulk materials in a suitable low-temperature environment. However, the existing support structure design fails to fully consider the heat conduction and mechanical properties in the low-temperature environment, resulting in insufficient thermal uniformity and heat leakage control. This design defect significantly affects the overall performance of the cryogenic container, increasing heat loss and reducing the working efficiency of superconducting bulk materials, thereby affecting the running stability of the maglev train. The current support structure design is often relatively rough, lacking effective analysis of the heat conduction path, resulting in the inability to achieve ideal thermal management when the superconducting bulk material is subjected to electromagnetic force. In addition, the existing design methods fail to effectively distribute and conduct the heat generated by the superconducting bulk material, causing unstable temperature control during long-term operation. Therefore, designing a support structure that can balance heat transfer efficiency and good mechanical strength is the key to improving the performance of the cryogenic container.

[0003] In view of the limitations of the existing technology, this application proposes a conduction-cooled superconductor cryogenic container and a design method for its honeycomb heat transfer structure. Summary of the Invention

[0004] The purpose of the present invention is to provide a conduction-cooled superconductor cryogenic container and a design method for its honeycomb heat transfer structure to improve the above problems. To achieve the above purpose, the technical solutions adopted by the present invention are as follows:

[0005] In a first aspect, this application provides a conduction-cooled superconductor cryogenic container, including: a refrigerator and a cryogenic container. The refrigerator is fixedly connected to the bottom of the vehicle body of the maglev train. The refrigerator includes a cold head heat conduction column. The cryogenic container includes an outer cavity, superconducting bulk materials, a copper box, and a honeycomb support heat transfer structure. The outer cavity includes a cover plate and a rectangular cavity that are fixedly connected to each other. The inside of the outer cavity is a vacuum environment. The refrigerator is fixedly arranged on the side of the outer cavity. The cover plate is fixedly connected to the bottom of the vehicle body of the maglev train. The rectangular cavity is arranged between the cover plate and the permanent magnet track. The copper box is fixedly arranged at the bottom of the rectangular cavity. The superconducting bulk materials are fixedly arranged inside the copper box. The cold head heat conduction column passes through the through hole on the side wall of the outer cavity and contacts the copper box. The honeycomb support heat transfer structure is arranged between the copper box and the cover plate.

[0006] Further, at least one groove is formed on the surface of the copper box facing the bottom of the outer cavity. The groove cooperates with the superconducting bulk material, and the superconducting bulk material is fixedly arranged in the groove. The depth of the groove is greater than or equal to the installation height of the superconducting bulk material.

[0007] Further, the superconducting bulk material is bonded in the groove.

[0008] Further, the number of the superconducting bulk materials is at least two, and all the superconducting bulk materials are arranged on the copper box at equal intervals according to a 2×N array, where N is a natural number greater than or equal to 1.

[0009] Further, the cryogenic container further includes a vacuum pump interface, a vacuum gauge interface, and a aviation plug interface. The vacuum pump interface, the vacuum gauge interface, and the aviation plug interface are all arranged on the outer wall of the outer cavity. The vacuum pump is connected to the inside of the outer cavity through the vacuum pump interface. The vacuum gauge interface is used to connect a vacuum gauge, and the aviation plug interface is used to connect an aviation plug.

[0010] Further, the cryogenic container includes a side wall support rod group and a bottom wall support rod group. One end of the bottom wall support rod group is fixedly connected to the bottom of the copper box, and the other end is fixedly connected to the bottom wall of the outer cavity. One end of the side wall support rod group is fixedly connected to the side of the copper box, and the other end is fixedly connected to the side wall of the outer cavity.

[0011] Further, the honeycomb-shaped support heat transfer structure includes a rectangular thin wall and a hexagonal thin wall. The hexagonal thin wall is arranged inside the rectangular thin wall. Each corner of the hexagonal thin wall extends a straight reinforcing rib. One end of all the straight reinforcing ribs is fixedly connected to each corner of the hexagonal thin wall, and the other end is fixedly connected to the inner side of the rectangular thin wall.

[0012] Further, at least one through hole is formed on each surface of the rectangular thin wall and the hexagonal thin wall.

[0013] Further, the material of the honeycomb-shaped support heat transfer structure is G-10 fiberglass.

[0014] In a second aspect, the present application provides a design method for a honeycomb-shaped heat transfer structure of a conduction-cooled superconductor type cryogenic container, including:

[0015] Obtaining the cooling capacity output of the refrigerator, the physical parameters of the honeycomb-shaped support heat transfer structure, and the design allowable values. The physical parameters include the material thermal conductivity and the mechanical strength, and the design allowable values include the allowable heat leakage and the stress limit;

[0016] Calculate the heat conduction efficiency of the support heat transfer structure based on the cold output and the material heat conductivity, and establish a preliminary support structure model through modeling based on the heat conduction efficiency and the design allowable value;

[0017] Perform optimization processing based on the preliminary support structure model, calculate the heat conduction path under different unit sizes through heat transfer analysis, and calculate the stress concentration under different combination of set parameters through mechanical analysis. Optimize the size, wall thickness and distribution of stiffeners of the honeycomb unit respectively to obtain an optimized design scheme;

[0018] Perform numerical simulation processing according to the optimized design scheme, and obtain the stress distribution of the honeycomb support heat transfer structure under different aperture sizes through the application of equivalent stress and parametric scanning analysis;

[0019] Perform strength checking processing according to the stress distribution to obtain an opening scheme that meets the preset structural strength requirements;

[0020] Integrate the opening scheme and the optimized design scheme to obtain the final design scheme of the honeycomb support heat transfer structure.

[0021] The beneficial effects of the present invention are as follows:

[0022] The honeycomb support heat transfer structure adopted by the present invention combines the designs of rectangular thin walls and hexagonal thin walls, making the overall structure not only lightweight but also have good mechanical properties. Straight stiffeners extend from each corner of the hexagonal thin wall, effectively dispersing stress concentration and enhancing the overall stability of the structure; The present invention analyzes the heat conduction path and stress concentration through parameter optimization and numerical simulation means, comprehensively optimizes the size, wall thickness and distribution of honeycomb units, effectively reduces the heat conduction efficiency, and ensures the long-term stability and reliability of the cryogenic container.

[0023] Other features and advantages of the present invention will be described in the subsequent specification, and, in part, will be obvious from the specification, or can be understood by implementing the embodiments of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures specifically pointed out in the written specification, claims, and drawings. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0025] Figure 1Schematic structural diagram of the conduction-cooled superconductor cryogenic container described in the embodiments of the present invention;

[0026] Figure 2 Internal schematic diagram of the cryogenic container described in the embodiments of the present invention;

[0027] Figure 3 Schematic structural diagram of the copper box described in the embodiments of the present invention;

[0028] Figure 4 Schematic structural diagram of the outer cavity described in the embodiments of the present invention;

[0029] Figure 5 Schematic structural diagram of the honeycomb support heat transfer structure described in the embodiments of the present invention;

[0030] Figure 6 Flowchart of the honeycomb heat transfer structure design method for the conduction-cooled superconductor cryogenic container described in the embodiments of the present invention;

[0031] Figure 7 Contour map of the deformation amount distribution of the honeycomb support heat transfer structure;

[0032] Figure 8 Contour map of the stress distribution of the honeycomb support heat transfer structure in the case of a pore diameter of 16 mm.

[0033] Markings in the figure: 1, refrigerator; 11, cold head heat conduction column; 2, cryogenic container; 21, outer cavity; 211, cover plate; 212, rectangular cavity; 22, superconducting bulk material; 23, copper box; 24, honeycomb support heat transfer structure; 241, rectangular thin wall; 242, hexagonal thin wall; 243, reinforcing rib; 25, vacuum pump interface; 26, vacuum gauge interface; 27, aviation plug interface; 28, side wall support rod group; 29, bottom wall support rod group. Detailed implementation manners

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. The components of the embodiments of the present invention usually described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0035] It should be noted that similar reference numerals and letters denote similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. At the same time, in the description of the present invention, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0036] Embodiment 1:

[0037] This embodiment provides a conduction-cooled superconductor cryogenic container. The core of this container is to ensure the efficient operation of the superconducting bulk material 22 in a low-temperature environment through the collaborative work of the refrigerator 1 and the cryogenic container 2. As Figure 1 , Figure 2 and Figure 3 shown, it includes a refrigerator 1 and a cryogenic container 2. The refrigerator 1 includes a cold head heat conduction column 11; the cryogenic container 2 includes an outer cavity 21, a superconducting bulk material 22, a copper box 23, and a honeycomb support heat transfer structure 24. The outer cavity 21 includes a cover plate 211 and a rectangular cavity 212 that are fixedly connected to each other. The inside of the outer cavity 21 is a vacuum environment, which significantly reduces the conduction and convective heat losses, thereby improving the working efficiency of the superconducting bulk material 22. The refrigerator 1 is fixedly arranged on the side of the outer cavity 21, and the refrigerator 1 and the cryogenic container 2 are arranged on both sides respectively, effectively reducing the overall height of the device. The cover plate 211 is fixedly connected to the bottom of the car body of the maglev train, the rectangular cavity 212 is arranged between the cover plate 211 and the permanent magnet track, the copper box 23 is fixedly arranged at the bottom of the rectangular cavity 212, and the superconducting bulk material 22 is fixedly arranged inside the copper box 23. The cold head heat conduction column 11 of the refrigerator 1 is directly in contact with the copper box 23, and effective heat transfer is achieved through the through hole. This design effectively reduces the heat loss during the cooling process, while ensuring the compact layout of the refrigerator 1 and the overall stability of the system. The honeycomb support heat transfer structure 24 arranged between the copper box 23 and the cover plate 211 not only realizes the support function but also optimizes the heat conduction path. At the same time, the design of this structure makes the stress distribution more uniform, effectively reducing the local stress concentration phenomenon and improving the strength and stability of the overall structure.

[0038] Preferably, as Figure 3As shown, at least one groove is provided on the surface of the copper box 23 facing the bottom of the outer cavity 21. The groove cooperates with the superconducting bulk material 22, and the superconducting bulk material 22 is fixedly arranged in the groove. The depth of the groove is greater than or equal to the installation height of the superconducting bulk material 22. The presence of the groove cooperates with the shape and size of the superconducting bulk material 22, enabling the superconducting bulk material 22 to be firmly fixed in the groove, thereby enhancing its stability and safety. This design not only avoids the displacement and vibration of the superconducting bulk material 22 during operation but also ensures its effective thermal contact in a low-temperature environment, promoting the improvement of the cooling effect. The depth of the groove being greater than or equal to the installation height of the superconducting bulk material 22 further strengthens the fixing effect.

[0039] Preferably, as Figure 3 shown, the superconducting bulk material 22 is adhesively bonded in the groove. By using a high-performance adhesive material, a firm and efficient thermal contact interface can be ensured between the superconducting bulk material 22 and the copper box 23, which can effectively reduce the heat conduction efficiency and ensure the optimal working state of the superconducting bulk material 22 in a low-temperature environment.

[0040] Preferably, as Figure 3 shown, the number of superconducting bulk materials is at least 2, and all superconducting bulk materials are arranged equidistantly on the copper box according to a 2×N array, where N is a natural number greater than or equal to 1. This uniform arrangement can effectively disperse the electromagnetic force received by the superconducting bulk material 22 and minimize the thermal gradient to ensure that each superconducting bulk material 22 can work under optimal low-temperature conditions.

[0041] Preferably, as Figure 4 shown, the cryogenic container 2 further includes a vacuum pump interface 25, a vacuum gauge interface 26, and a aviation plug interface 27. The vacuum pump interface 25, the vacuum gauge interface 26, and the aviation plug interface 27 are all arranged on the outer wall of the outer cavity 21. The vacuum pump is connected to the inside of the outer cavity 21 through the vacuum pump interface 25, and the vacuum gauge interface 26 is used to connect a vacuum gauge. This design allows for the rapid and effective extraction of air inside the cryogenic container 2 to ensure a stable vacuum state is maintained inside the container and to monitor the internal vacuum degree of the cryogenic container 2 at any time to maintain a stable evacuation state. The aviation plug interface 27 is used to connect an aviation plug. The aviation plug interface 27 is connected to the temperature sensing system inside the cryogenic container 2. The setting of the aviation plug interface 27 provides an important connection point for the temperature sensing system inside the cryogenic container 2. Through this interface, a temperature sensor can be connected to monitor the temperature of the superconducting bulk material 22 in real time to ensure that it is always within the optimal working range. This function is crucial for maintaining the performance of high-temperature superconducting materials because the performance of the superconducting bulk material 22 fluctuates with temperature, and real-time temperature feedback can adjust the cooling system in a timely manner to ensure the stability and reliability of the superconductor performance.

[0042] Preferably, as Figure 3As shown, the cryogenic container 2 includes a side wall support rod group 28 and a bottom wall support rod group 29, and this design significantly enhances the structural stability and load-bearing capacity of the container. One end of the bottom wall support rod group 29 is fixedly connected to the bottom of the copper box 23, and the other end is fixedly connected to the bottom wall of the outer cavity 21. This configuration effectively transfers the electromagnetic forces received by the superconducting bulk material 22 and the copper box 23 to the outer cavity 21, ensuring that the stress can be evenly distributed throughout the system during operation, avoiding local stress concentration, and thus reducing the risk of structural damage. The side wall support rod group 28 further enhances the overall rigidity of the container. One end of it is fixedly connected to the side of the copper box 23, and the other end is fixedly connected to the side wall of the outer cavity 21. This design not only provides additional support to ensure the container's ability to withstand external vibrations and impacts during high-speed operation but also optimizes the heat conduction path of the container, facilitating the maintenance of a cryogenic environment.

[0043] Preferably, as Figure 5 shown, the honeycomb support heat transfer structure 24 includes a rectangular thin wall 241 and a hexagonal thin wall 242. The hexagonal thin wall 242 is arranged inside the rectangular thin wall 241. Each corner of the hexagonal thin wall 242 extends a straight reinforcing rib 243. One end of all the straight reinforcing ribs 243 is fixedly connected to each corner of the hexagonal thin wall 242, and the other end is fixedly connected to the inner side of the rectangular thin wall 241. The shape of the hexagonal thin wall 242 not only provides good structural stability while reducing the overall weight but also optimizes the force distribution through its unique geometry, enabling it to effectively resist deformation and displacement when the superconducting bulk material 22 is subjected to electromagnetic forces. Each corner of the hexagonal thin wall 242 extends a straight reinforcing rib 243, and this design significantly enhances the strength and stiffness of the thin wall. One end of all the straight reinforcing ribs 243 is fixedly connected to the corners of the hexagonal thin wall 242, and the other end is fixedly connected to the inner side of the rectangular thin wall 241, thus forming an effective force transfer path. This connection method ensures that during use, the structure can evenly distribute the externally applied load, reduce the phenomenon of local stress concentration, and thereby improve the durability of the overall structure. In addition, the design of the honeycomb support heat transfer structure 24 also helps to optimize the heat conduction path.

[0044] Preferably, as Figure 5 shown, at least one through hole is provided on each surface of the rectangular thin wall 241 and the hexagonal thin wall 242. The through holes are particularly important in a vacuum environment. They can effectively prevent damage to the thin wall structure caused by external air pressure differences. Through reasonable arrangement of the through holes, better air circulation can be achieved, preventing the accumulation of thermal stress caused by temperature changes, and thus ensuring the long-term stability of the structure under cryogenic conditions. In addition, the through holes can also facilitate subsequent maintenance and monitoring, making it convenient to install sensors or other monitoring devices to real-time monitor the working state and temperature changes of the superconducting bulk material 22.

[0045] Preferably, the material of the honeycomb support heat transfer structure 24 is G-10 fiberglass. G-10 fiberglass is a composite material with excellent mechanical properties and thermal stability. Its high strength and low density characteristics enable the honeycomb structure to significantly reduce the overall weight while ensuring the load-bearing capacity.

[0046] Example 2:

[0047] This embodiment provides a design method for the honeycomb heat transfer structure of a conduction-cooled superconductor cryogenic container.

[0048] See Figure 6 , the figure shows that this method includes step S100 to step S600.

[0049] Step S100, obtain the cooling capacity output of the refrigerator 1, the physical parameters and design allowable values of the honeycomb support heat transfer structure 24. The physical parameters include material thermal conductivity and mechanical strength, and the design allowable values include allowable heat leakage and stress limit;

[0050] It can be understood that the cooling capacity output of the refrigerator 1 refers to its refrigeration capacity under specific conditions. Thermal conductivity is a key indicator to measure the heat conduction ability of materials. Selecting an appropriate material thermal conductivity is crucial for optimizing thermal management and improving heat transfer efficiency. At the same time, the mechanical strength parameter ensures that the support structure can maintain stability when subjected to electromagnetic force and other external loads, avoiding structural damage caused by insufficient mechanical properties. The allowable heat leakage refers to the acceptable heat loss amount during the normal operation of the system. This indicator is directly related to the working temperature and cooling effect of the superconducting bulk 22, so it must be accurately evaluated at the initial stage of design. The stress limit refers to the maximum stress value that the support structure can withstand under the action of the load, ensuring that it will not fail due to exceeding the material strength in practical applications.

[0051] Step S200, calculate the heat conduction efficiency of the support heat transfer structure according to the cooling capacity output and the material thermal conductivity, and build a model based on the heat conduction efficiency and the design allowable values to obtain a preliminary support structure model;

[0052] It should be noted that the cooling capacity output provides the refrigeration capacity required by the system, while the material thermal conductivity reflects the efficiency of heat propagation in the support structure. By combining these two, a heat conduction model can be established to determine the flow path and rate of heat in the support heat transfer structure. This model will provide basic data for subsequent optimization, enabling designers to identify possible heat loss areas and make targeted improvements. Next, based on the calculated heat conduction efficiency and the previously determined design allowable values (such as allowable heat leakage and stress limits), a model is built to obtain a preliminary support structure model. This model not only considers the heat conduction characteristics but also incorporates the requirements of mechanical properties. Through the comprehensive analysis of heat and force, the preliminary model can ensure the effective cooling of the superconducting bulk 22 while meeting the requirements of structural strength and stability.

[0053] Step S300: Perform optimization processing based on the preliminary support structure model. Calculate the heat conduction path under different unit sizes based on heat transfer analysis, and calculate the stress concentration under different combination of set parameters based on mechanical analysis. Optimize the size, wall thickness, and distribution of the reinforcing ribs 243 of the honeycomb unit respectively to obtain an optimized design scheme.

[0054] It can be understood that this process involves in-depth analysis of the stress behavior of the honeycomb structure under different load conditions to identify possible stress concentration areas and ensure that material failure or structural damage does not occur in actual applications. The stress analysis will guide the designer to make reasonable choices in terms of size, wall thickness, and distribution of the reinforcing ribs 243 to ensure that the support structure has sufficient strength and stability when bearing electromagnetic force and other external loads. Specifically, the size, wall thickness, and distribution of the reinforcing ribs 243 of the honeycomb unit will be optimized respectively. By comprehensively considering the heat transfer efficiency and mechanical properties, a more ideal honeycomb-shaped support structure scheme can be obtained. This optimized design scheme not only improves the cooling efficiency of the superconducting bulk 22 but also enhances the durability and reliability of the structure, enabling the cryogenic container 2 to maintain a good working state during long-term operation.

[0055] Step S400: Perform numerical simulation processing based on the optimized design scheme. Through the application of equivalent stress and parametric scanning analysis, obtain the stress distribution of the honeycomb-shaped support heat transfer structure 24 under different pore sizes.

[0056] Furthermore, numerical simulation involves using finite element analysis (FEA) software to model the optimized design solution. By applying equivalent stresses in different directions and magnitudes, the distribution of stresses within the structure is observed. This analysis helps designers identify stress concentration areas and evaluate the load-bearing capacity of the structure under extreme conditions. The advantage of this method is that multiple tests can be efficiently conducted in a computer environment, avoiding the high costs and time consumption of actual manufacturing and testing. In addition, parametric sweep analysis refers to evaluating the impact of gradually adjusting the aperture size on the stress distribution. This process enables designers to clearly understand how changes in the aperture size affect the mechanical properties of the honeycomb structure, thereby optimizing the aperture design to achieve the best thermal management and structural strength. By analyzing the stress distribution under different aperture sizes, designers can ensure that while meeting the internal heat conduction requirements of the cryogenic vessel 2, local stress concentration and potential structural failure caused by improper aperture settings are prevented.

[0057] Step S500: Perform strength verification processing based on the stress distribution to obtain an opening plan that meets the preset structural strength requirements.

[0058] It should be noted that by evaluating the impact of different aperture settings, it is possible to determine which hole positions and sizes can optimize heat conduction and reduce the overall weight while ensuring structural strength. This plan will ensure proper thermal management within the structure while avoiding potential weaknesses caused by excessive openings.

[0059] Step S600: Integrate the opening plan and the optimized design solution to obtain the final design solution for the honeycomb support heat transfer structure 24.

[0060] It can be understood that during the integration process, the stress distribution of the overall structure will be re-evaluated to ensure that the strength of the structure still meets the preset requirements after adding holes. This evaluation includes comprehensively considering the dimensions, wall thicknesses of each honeycomb cell, the distribution of stiffeners 243, and the configuration of holes to ensure the stability and durability of the structure.

[0061] Specifically, in this cryogenic vessel 2, it is all solid heat conduction. The refrigerator 1 can cool the superconducting bulk 22 to below 77K to further increase the levitation force. Reducing the heat leakage of the cryogenic vessel 2 and controlling the heat leakage of the cryogenic vessel 2 system within a reasonable range is the key to determining whether this cryogenic vessel 2 can cool the superconducting bulk 22 to the target temperature. Therefore, it is necessary to conduct a heat leakage verification calculation for the constant temperature system. The main path of cold quantity transfer is that the cold quantity generated at the cold head of the refrigerator 1 is transferred to the copper box 23, and then the copper box 23 transfers the cold quantity to the superconducting bulk 22. However, due to the existence of contact thermal resistance in heat transfer between solids, especially at low temperatures, there is a certain temperature difference between the copper box 23 and the superconducting bulk 22. The heat conduction equation involved is as follows:

[0062]

[0063] where ρ is the density of the material; C is the specific heat capacity of the material; T is the temperature; t is the time; k is the thermal conductivity; is the divergence of the heat flux, representing the spatial variation of the conducted heat; Q is the heat source or heat sink power per unit volume.

[0064] The two sides of the remaining supports are the high-temperature end and the low-temperature end respectively. Therefore, heat leakage occurs through heat conduction, and the calculation formula is as follows:

[0065]

[0066] where q is the heat leakage; λ is the thermal conductivity; δ is the thickness; Δt is the heat transfer temperature difference.

[0067] In addition, the heat leakage of the cryogenic container is mainly radiative heat leakage. The normal temperature wall will emit heat to the low temperature wall, resulting in the absorption of heat at the low temperature end. The calculation formula for radiative heat leakage is as follows:

[0068]

[0069] where Q rad is the radiative heat exchange; ε1 is the emissivity of the irradiated object; ε2 is the emissivity of the irradiating object; A1 is the area of the irradiated object; T1 is the temperature of the irradiated object; A2 is the area of the irradiating object; T2 is the temperature of the irradiating object; N is the number of layers of the multi-layer insulation material.

[0070] Therefore, the cooling capacity of the refrigerator 1 needs to be greater than the heat leakage of the entire cryogenic container 2. It is found from the previous research results that a large amount of heat leakage comes from heat conduction leakage. Therefore, the support heat transfer structure is mainly designed and optimized. Five-point, cross, grid, and honeycomb structures have been tried successively. After comprehensively considering factors such as conduction heat leakage, structural stress, and structural lightweight, a honeycomb support structure is decided to be adopted to reduce the heat transfer area to achieve the effect of reducing heat leakage.

[0071] Although the initial five-point support structure has the smallest conduction heat leakage, the local stress is too large, and there is a risk of support column fracture. Therefore, it is considered to increase the cross-sectional area. The grid structure has a smaller cross-sectional area than the cross structure, and the volume is reduced by twice, and the stress is reduced by half, and there will be no stress concentration at the edges of the cross structure. The honeycomb structure has high stability and efficient mechanical properties, and can achieve the maximum strength and stiffness with the least amount of material. Compared with the grid structure, the stress is reduced by more than twice, and the volume and conduction heat leakage are both significantly reduced.

[0072] The materials supporting the heat transfer structure are all G-10 fiberglass. The maximum stress of the honeycomb-shaped heat transfer support structure is 123 MPa, which appears at the connection of the thin wall top connected to the copper box 23. The stress of the remaining parts is less than 100 MPa, all meeting the strength requirements of G-10 fiberglass. Figure 7 It is the deformation distribution diagram of the thin-wall low-temperature support. It can be seen that the deformation mainly occurs at the top of the thin wall, and the stress received here is also relatively large. The maximum value is 0.278 mm, and the deformation amount is within the allowable range.

[0073] For the honeycomb-shaped heat transfer support structure, considering that the internal space of the thin wall cannot be evacuated smoothly, holes need to be drilled on the thin-wall support. The size of the holes should be as large as possible under the condition of meeting the strength check, which can also reduce the conduction heat leakage to a certain extent. Therefore, equivalent stress is applied to the honeycomb-shaped heat transfer support structure, and then parametric scanning is used to change the hole diameter from 4 mm to 20 mm to obtain the stress conditions of the honeycomb-shaped heat transfer support structure under different hole diameters, and the maximum hole diameter is selected under the condition of meeting the strength check. As Figure 8 shown, Figure 8 It shows the stress nephogram of the honeycomb-shaped heat transfer support structure with a hole diameter of 16 mm. It can be seen from the figure that under the premise of meeting the strength, the maximum hole diameter is 16 mm. At the same time, the maximum stress points are mainly concentrated around the holes. Although the existence of the holes increases the maximum stress value to 274 MPa, it also reduces the conduction heat leakage, which is beneficial to the thermodynamic performance of the entire conduction-cooled superconductor cryogenic container.

[0074] As mentioned above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A conduction-cooled superconducting cryogenic vessel, characterized in that, Comprising: A refrigerator (1), which is fixedly connected to the bottom of the car body of the maglev train. The refrigerator (1) includes a cold head heat conduction column (11); and A cryogenic container (2), which includes an outer cavity (21), superconducting blocks (22), a copper box (23), and a honeycomb support heat transfer structure (24). The outer cavity (21) includes a cover plate (211) and a rectangular cavity (212) that are fixedly connected to each other. The inside of the outer cavity (21) is a vacuum environment. The refrigerator (1) is fixedly arranged on the side of the outer cavity (21). The cover plate (211) is fixedly connected to the bottom of the car body of the maglev train. The rectangular cavity (212) is arranged between the cover plate (211) and the permanent magnet track. The copper box (23) is fixedly arranged at the bottom of the rectangular cavity (212). The superconducting blocks (22) are fixedly arranged inside the copper box (23). The cold head heat conduction column (11) passes through a through hole in the side wall of the outer cavity (21) and contacts the copper box (23). The honeycomb support heat transfer structure (24) is arranged between the copper box (23) and the cover plate (211).

2. The conduction-cooled superconducting cryogenic vessel according to claim 1, wherein: At least one groove is formed on the surface of the copper box (23) facing the bottom of the outer cavity (21). The groove cooperates with the superconducting blocks (22). The superconducting blocks (22) are fixedly arranged in the groove. The depth of the groove is greater than or equal to the installation height of the superconducting blocks (22).

3. The conduction-cooled superconducting cryogenic container according to claim 2, wherein: The superconducting blocks (22) are bonded in the groove.

4. The conduction-cooled superconducting cryogenic vessel according to claim 3, characterized in that: The number of the superconducting blocks (22) is at least 2. All the superconducting blocks (22) are arranged on the copper box (23) at equal intervals in a 2×N array, where N is a natural number greater than or equal to 1.

5. The conduction-cooled superconducting cryogenic container according to claim 1, wherein: The cryogenic container (2) further includes a vacuum pump interface (25), a vacuum gauge interface (26), and a aviation plug interface (27). The vacuum pump interface (25), the vacuum gauge interface (26), and the aviation plug interface (27) are all arranged on the outer wall of the outer cavity (21). The vacuum machine is connected to the inside of the outer cavity (21) through the vacuum pump interface (25). The vacuum gauge interface (26) is used to connect a vacuum gauge. The aviation plug interface (27) is used to connect an aviation plug.

6. The conduction-cooled superconductor cryogenic container according to claim 1, wherein: The cryogenic container (2) includes a side wall support rod group (28) and a bottom wall support rod group (29). One end of the bottom wall support rod group (29) is fixedly connected to the bottom of the copper box (23), and the other end is fixedly connected to the bottom wall of the outer cavity (21). One end of the side wall support rod group (28) is fixedly connected to the side of the copper box (23), and the other end is fixedly connected to the side wall of the outer cavity (21).

7. The conduction-cooled superconducting cryogenic container according to claim 1, characterized in that: The honeycomb support heat transfer structure (24) includes a rectangular thin wall (241) and a hexagonal thin wall (242). The hexagonal thin wall (242) is disposed within the rectangular thin wall (241). Each corner of the hexagonal thin wall (242) extends a linear reinforcing rib (243). One end of all the linear reinforcing ribs (243) is fixedly connected to each corner of the hexagonal thin wall (242), and the other end is fixedly connected to the inner side of the rectangular thin wall (241).

8. The conduction-cooled superconductor cryogenic container according to claim 7, characterized in that: At least one through hole is formed on each surface of the rectangular thin wall (241) and the hexagonal thin wall (242).

9. The conduction-cooled superconductor cryogenic vessel according to claim 1, wherein: The material of the honeycomb support heat transfer structure (24) is G-10 fiberglass.

10. A design method for a honeycomb heat transfer structure of a conduction-cooled superconductor cryogenic container, characterized in that, The method uses the conduction-cooled superconductor type cryogenic container according to any one of claims 1-9. The method includes: Obtaining the cooling output of the refrigerator (1), the physical parameters of the honeycomb support heat transfer structure (24), and the design allowable values. The physical parameters include material thermal conductivity and mechanical strength, and the design allowable values include allowable heat leakage and stress limit; Calculating the heat conduction efficiency of the support heat transfer structure based on the cooling output and the material thermal conductivity, and performing modeling based on the heat conduction efficiency and the design allowable values to obtain a preliminary support structure model; Performing an optimization process according to the preliminary support structure model, calculating the heat conduction path under different unit sizes based on heat transfer analysis, and calculating the stress concentration under different set parameter combinations based on mechanical analysis. Optimizing the size, wall thickness, and distribution of the reinforcing ribs (243) of the honeycomb unit respectively to obtain an optimized design scheme; Performing a numerical simulation process according to the optimized design scheme, and obtaining the stress distribution of the honeycomb support heat transfer structure (24) under different pore sizes through applying equivalent stress and parametric scanning analysis; Performing a strength check process according to the stress distribution to obtain an opening scheme that meets the preset structural strength requirements; Integrating the opening scheme and the optimized design scheme to obtain the final design scheme of the honeycomb support heat transfer structure (24).

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