Conduction cooling superconductor type low-temperature container and honeycomb heat transfer structure design method thereof

Abstract

The invention provides a conduction cooling superconductor type low-temperature container and a honeycomb heat transfer structure design method thereof, and relates to the technical field of high-temperature superconducting magnetic levitation, and the conduction cooling superconductor type low-temperature container comprises a refrigerator and a low-temperature container. The refrigerating machine comprises a cold head cold guide column; the low-temperature container comprises an outer cavity, a superconducting block, a copper box and a honeycomb-shaped supporting heat transfer structure, the outer cavity comprises a cover plate and a rectangular cavity which are fixedly connected with each other, the refrigerating machine is fixedly arranged on the side face of the outer cavity, the cover plate is fixedly connected with the bottom of a train body of the maglev train, and the copper box is fixedly arranged at the bottom of the rectangular cavity. The superconducting block is fixedly arranged in the copper box, the cold head cold conduction column penetrates through a through hole in the side wall of the outer cavity to be fixedly connected with the copper box, and the honeycomb-shaped supporting heat transfer structure is arranged between the copper box and the cover plate. By analyzing the heat conduction path and the stress concentration condition, the size, the wall thickness and the reinforcing rib distribution of the honeycomb unit are comprehensively optimized, the heat conduction efficiency is effectively reduced, and the long-term stability and reliability of the low-temperature container are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature superconducting magnetic levitation, and in particular to a conduction-cooled superconductor type cryogenic container and a design method for a honeycomb heat transfer structure thereof. Background Art

[0002] Conduction-cooled superconductor cryogenic vessels play a key role in high-temperature superconducting maglev trains. Their main function is to ensure that superconducting bulk materials can operate efficiently in a suitable low-temperature environment. However, the existing support structure design fails to fully consider the thermal conduction and mechanical properties in a low-temperature environment, resulting in insufficient thermal uniformity and heat leakage control. This design defect significantly affects the overall performance of the cryogenic vessel, increases heat loss and reduces the working efficiency of the superconducting bulk materials, thereby affecting the operating stability of the maglev train. The current support structure design is often rough and lacks effective analysis of the heat conduction path, resulting in the inability to achieve ideal thermal management when the superconducting bulk materials are subjected to electromagnetic forces. In addition, the existing design methods fail to effectively distribute and conduct the heat generated by the superconducting bulk materials, resulting in unstable temperature control during long-term operation. Therefore, designing a support structure that can take into account both heat transfer efficiency and good mechanical strength has become the key to improving the performance of cryogenic vessels.

[0003] In view of the limitations of the prior art, the present 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 honeycomb heat transfer structure design method thereof to improve the above problems. In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0005] In the first aspect, the present application provides a conduction-cooled superconductor cryogenic container, comprising: a refrigerator and a cryogenic container. The refrigerator is fixedly connected to the bottom of the body of the maglev train, and the refrigerator includes a cold head cooling column; the cryogenic container includes an outer cavity, a superconducting block, a copper box, and a honeycomb supporting heat transfer structure. The outer cavity includes a cover plate and a rectangular cavity fixedly connected to each other, and the interior 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 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 block is fixedly arranged inside the copper box, the cold head cooling column passes through the through hole of the side wall of the outer cavity to contact the copper box, and the honeycomb supporting heat transfer structure is arranged between the copper box and the cover plate.

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

[0007] Furthermore, the superconducting block is bonded in the groove.

[0008] Furthermore, the number of the superconducting blocks is at least 2, and all the superconducting blocks are equidistantly arranged on the copper box in a 2×N array, where N is a natural number greater than or equal to 1.

[0009] Furthermore, the low-temperature container also includes a vacuum pump interface, a vacuum gauge interface and an aviation plug interface, and the vacuum pump interface, the vacuum gauge interface and the aviation plug interface are all arranged on the outer wall of the outer cavity, and the vacuum machine is connected to the interior of the outer cavity through the vacuum pump interface, the vacuum gauge interface is used to connect the vacuum gauge, and the aviation plug interface is used to connect the aviation plug.

[0010] Furthermore, the low-temperature 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] Furthermore, the honeycomb supporting heat transfer structure includes a rectangular thin wall and a hexagonal thin wall, the hexagonal thin wall is arranged inside the rectangular thin wall, and 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] Furthermore, at least one through hole is formed on each surface of the rectangular thin wall and the hexagonal thin wall.

[0013] Furthermore, the honeycomb supporting heat transfer structure is made of G-10 fiberglass.

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

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

[0016] The heat transfer efficiency of the supporting heat transfer structure is calculated according to the cooling output and the thermal conductivity of the material, and a preliminary supporting structure model is obtained by modeling based on the heat transfer efficiency and the design allowable value;

[0017] Optimizing the preliminary support structure model, calculating the heat conduction path under different unit sizes based on heat transfer analysis, calculating the stress concentration under different set parameter combinations based on mechanical analysis, optimizing the size, wall thickness and rib distribution of the honeycomb unit, and obtaining an optimized design solution;

[0018] Numerical simulation is performed according to the optimization design scheme, and stress distribution of the honeycomb support heat transfer structure under different pore sizes is obtained by applying equivalent stress and parametric scanning analysis;

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

[0020] The final honeycomb support heat transfer structure design scheme is obtained by integrating the hole opening scheme and the optimization design scheme.

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

[0022] The honeycomb support heat transfer structure adopted by the present invention combines the design of rectangular thin walls and hexagonal thin walls, so that the overall structure is not only lightweight but also has good mechanical properties. Straight reinforcing ribs extend from each corner of the hexagonal thin wall, which effectively disperses stress concentration and enhances the overall stability of the structure. The present invention analyzes the heat conduction path and stress concentration through parameter optimization and numerical simulation, comprehensively optimizes the size, wall thickness and reinforcing rib distribution of the honeycomb unit, effectively reduces the heat conduction efficiency, and ensures the long-term stability and reliability of the low-temperature container.

[0023] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or be understood by implementing the embodiments of the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0025] Figure 1It is a schematic structural diagram of a conduction-cooled superconductor cryogenic container according to an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the interior of a cryogenic container according to an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the copper box structure described in an embodiment of the present invention;

[0028] Figure 4 Schematic diagram of the outer cavity structure described in an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of a honeycomb support heat transfer structure described in an embodiment of the present invention;

[0030] Figure 6 It is a flow chart of a method for designing a honeycomb heat transfer structure of a conduction-cooled superconductor cryogenic container according to an embodiment of the present invention;

[0031] Figure 7 It is the deformation distribution cloud diagram of the honeycomb support heat transfer structure;

[0032] Figure 8 This is the stress distribution cloud diagram of the honeycomb support heat transfer structure with a pore diameter of 16mm.

[0033] Markings in the figure: 1. Refrigerator; 11. Cold head cooling column; 2. Low temperature container; 21. External cavity; 211. Cover plate; 212. Rectangular cavity; 22. Superconducting block; 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 DESCRIPTION

[0034] In order to make the purpose, 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 in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention generally described and shown in the 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 drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. At the same time, in the description of the present invention, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0036] Embodiment 1:

[0037] This embodiment provides a conduction-cooled superconductor cryogenic container, the core of which is to ensure that the superconducting block 22 operates efficiently in a low-temperature environment through the coordinated work of the refrigerator 1 and the cryogenic container 2. Figure 1 , Figure 2 and Figure 3 As shown, it includes a refrigerator 1 and a cryogenic container 2. The refrigerator 1 includes a cold head cooling column 11; the cryogenic container 2 includes an outer cavity 21, a superconducting block 22, a copper box 23, and a honeycomb supporting heat transfer structure 24. The outer cavity 21 includes a cover plate 211 and a rectangular cavity 212 fixedly connected to each other. The interior of the outer cavity 21 is a vacuum environment, which significantly reduces conduction and convection heat losses, thereby improving the working efficiency of the superconducting block 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 respectively arranged on both sides, which effectively reduces the overall height of the device. The cover plate 211 is fixedly connected to the bottom of the 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 block 22 is fixedly arranged inside the copper box 23. The cold head cooling column 11 of the refrigerator 1 is in direct contact with the copper box 23, and effective cold transfer is achieved through the through hole. This design effectively reduces heat loss during the cooling process, while ensuring the compact layout of the refrigerator 1 and the overall stability of the system. The arrangement of the honeycomb support heat transfer structure 24 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 the structure makes the stress distribution more uniform, effectively reduces the local stress concentration phenomenon, and improves the strength and stability of the overall structure.

[0038] Preferably, if 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, and the groove cooperates with the superconducting block 22. The superconducting block 22 is fixedly arranged in the groove, and the depth of the groove is greater than or equal to the installation height of the superconducting block 22. The existence of the groove cooperates with the shape and size of the superconducting block 22, so that the superconducting block 22 can be firmly fixed in the groove, thereby enhancing its stability and safety. This design not only avoids the displacement and vibration of the superconducting block 22 during operation, but also ensures its effective thermal contact in a low-temperature environment, and promotes the improvement of the cooling effect. The depth of the groove is greater than or equal to the installation height of the superconducting block 22, which further enhances the fixing effect.

[0039] Preferably, if Figure 3 As shown, the superconducting block 22 is bonded in the groove. By using high-performance bonding materials, a strong and efficient thermal contact interface can be formed between the superconducting block 22 and the copper box 23, which can effectively reduce the heat conduction efficiency and ensure the best working state of the superconducting block 22 in a low-temperature environment.

[0040] Preferably, if Figure 3 As shown, the number of superconducting blocks is at least 2, and all superconducting blocks are equidistantly arranged on the copper box in 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 on the superconducting block 22 and minimize the thermal gradient, ensuring that each superconducting block 22 can work under optimal low temperature conditions.

[0041] Preferably, if Figure 4 As shown, the cryogenic container 2 also includes a vacuum pump interface 25, a vacuum gauge interface 26 and an 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 interior of the outer cavity 21 through the vacuum pump interface 25, and the vacuum gauge interface 26 is used to connect the vacuum gauge. This design allows the air inside the cryogenic container 2 to be quickly and effectively extracted, ensuring that a stable vacuum state is maintained in the container, and the internal vacuum degree of the cryogenic container 2 is monitored 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 connects 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 block 22 in real time to ensure that it is always within the optimal working range. This function is crucial for the performance maintenance of high-temperature superconducting materials, because the performance of the superconducting block 22 will fluctuate with changes in temperature, and real-time temperature feedback can adjust the cooling system in time to ensure the stability and reliability of the superconductor performance.

[0042] Preferably, if Figure 3As shown, the cryogenic container 2 includes a side wall support rod group 28 and a bottom wall support rod group 29. This design significantly enhances the structural stability and 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 transmits the electromagnetic force exerted on the superconducting block 22 and the copper box 23 to the outer cavity 21, ensuring that the entire system can evenly distribute stress during operation, avoiding local stress concentration, thereby reducing the risk of structural damage. The side wall support rod group 28 further enhances the overall rigidity of the container, one end of which 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 and ensures the ability of the container to resist external vibration and impact during high-speed operation, but also optimizes the heat conduction path of the container and promotes the maintenance of a low-temperature environment.

[0043] Preferably, if Figure 5 As 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 in 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 geometric shape, so that the superconducting block 22 can effectively resist deformation and displacement when the electromagnetic force acts on it. Each corner of the hexagonal thin wall 242 extends a straight reinforcing rib 243. This design significantly enhances the strength and rigidity of the thin wall. One end of all the straight reinforcing ribs 243 is fixedly connected to the corner of the hexagonal thin wall 242, and the other end is fixedly connected to the inner side of the rectangular thin wall 241, thereby forming an effective force transmission path. This connection method ensures that during use, the structure can evenly distribute the externally applied load, reduce local stress concentration, and thus 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, if Figure 5 As shown, at least one through hole is provided on each face of the rectangular thin wall 241 and the hexagonal thin wall 242. Through holes are particularly important in a vacuum environment, as they can effectively prevent damage to the thin-walled structure caused by external air pressure differences. Through the rational arrangement of through holes, better air circulation can be achieved, and the accumulation of thermal stress caused by temperature changes can be prevented, thereby ensuring the long-term stability of the structure under low temperature conditions. In addition, the through holes can also facilitate subsequent maintenance and monitoring, and facilitate the installation of sensors or other monitoring equipment to monitor the working status and temperature changes of the superconducting block 22 in real time.

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

[0046] Embodiment 2:

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

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

[0049] Step S100, obtaining the cooling output of the refrigerator 1, the physical parameters and the design allowable values ​​of the honeycomb supporting heat transfer structure 24, the physical parameters including the thermal conductivity and mechanical strength of the material, and the design allowable values ​​including the allowable heat leakage and stress limit;

[0050] It is understandable that the cooling output of the refrigerator 1 refers to the cooling capacity it can provide under specific conditions. Thermal conductivity is a key indicator to measure the ability of a material to conduct heat. Selecting the appropriate thermal conductivity of the material is essential for optimizing thermal management and improving heat transfer efficiency. At the same time, the mechanical strength parameters ensure that the support structure can maintain stability when subjected to electromagnetic forces and other external loads, avoiding structural damage due to insufficient mechanical properties. The allowable heat leakage refers to the amount of heat loss that is acceptable during normal operation of the system. This indicator is directly related to the operating temperature and cooling effect of the superconducting block material 22, so it must be accurately evaluated at the beginning of the design. Stress limitation refers to the maximum stress value that the support structure can withstand under the action of the load, ensuring that failure will not occur in actual applications due to exceeding the material strength.

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

[0052] It should be noted that the cold output provides the refrigeration capacity required by the system, while the thermal conductivity of the material reflects the efficiency of heat propagation in the supporting structure. Through the combination of the two, a heat conduction model can be established to determine the flow path and rate of heat in the supporting heat transfer structure. This model will provide basic data for subsequent optimization, allowing designers to identify possible areas of heat loss and make targeted improvements. Next, based on the calculated thermal conduction efficiency and the previously determined design allowable values ​​(such as allowable heat leakage and stress limits), modeling is performed to obtain a preliminary supporting structure model. This model not only takes into account the thermal conduction characteristics, but also incorporates the requirements of mechanical properties. Through a comprehensive analysis of heat and force, the preliminary model can meet the requirements of structural strength and stability while ensuring that the superconducting block 22 is effectively cooled.

[0053] Step S300, performing optimization processing 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, respectively optimizing the size, wall thickness and distribution of the reinforcing ribs 243 of the honeycomb unit to obtain an optimized design solution;

[0054] It is understandable that this process involves an 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 will not occur in actual applications. Stress analysis will guide designers to make reasonable choices in size, wall thickness and distribution of stiffeners 243 to ensure that the support structure has sufficient strength and stability when bearing electromagnetic forces and other external loads. Specifically, the size, wall thickness and distribution of stiffeners 243 of the honeycomb unit will be optimized respectively. By comprehensively considering the heat transfer efficiency and mechanical properties, a more ideal honeycomb support structure solution can be obtained. This optimized design scheme not only improves the cooling efficiency of the superconducting block 22, but also enhances the durability and reliability of the structure, so that the low-temperature container 2 can maintain a good working condition during long-term operation.

[0055] Step S400, performing numerical simulation processing according to the optimized design scheme, applying equivalent stress and performing parametric scanning analysis, and obtaining the stress distribution of the honeycomb support heat transfer structure 24 under different pore sizes;

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

[0057] Step S500, performing strength verification processing according to the stress distribution to obtain a hole opening scheme that meets the preset structural strength requirements;

[0058] It is important to note that by evaluating the impact of different hole diameter settings, it is possible to determine which hole locations and sizes can optimize heat conduction and reduce overall weight while ensuring structural strength. This approach will ensure that proper thermal management is maintained within the structure while avoiding potential weak points caused by excessive openings.

[0059] Step S600: Integrate the hole opening scheme and the optimization design scheme to obtain the final design scheme of the honeycomb support heat transfer structure 24.

[0060] It is understood that the stress distribution of the overall structure will be re-evaluated during the integration process to ensure that the strength of the structure still meets the preset requirements after the holes are added. This evaluation includes comprehensive consideration of the size, wall thickness, distribution of the reinforcing ribs 243 and the configuration of the holes of each honeycomb unit to ensure the stability and durability of the structure.

[0061] Specifically, in this cryogenic container 2, all heat is transferred by solid state, and the refrigerator 1 can reduce the temperature of the superconducting block 22 to below 77K to further increase the suspension force. Reducing the heat leakage of the cryogenic container 2 and controlling the heat leakage of the cryogenic container 2 system within a reasonable range are the key to determining whether the cryogenic container 2 can cool the superconducting block 22 to the target temperature. Therefore, the constant temperature system must be subjected to a heat leakage check calculation. The main path for cold energy transfer is that the cold energy generated at the cold head of the refrigerator 1 is transferred to the copper box 23, and the copper box 23 then transfers the cold energy to the superconducting block 22. However, due to the contact thermal resistance of heat transfer between solids and solids, especially at low temperatures, there is a certain temperature difference between the copper box 23 and the superconducting block 22. The heat conduction equation involved is as follows:

[0062]

[0063] Among them, 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 heat flow, indicating the spatial variation of heat conduction; Q is the heat source or heat sink power per unit volume.

[0064] The other two sides of the support are high temperature end and low temperature end respectively, so the heat leakage is through heat conduction, and the calculation formula is as follows:

[0065]

[0066] Among them, q is the amount of 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 radiation heat leakage. The normal temperature wall will emit heat to the low temperature wall, thus causing the absorption of heat at the low temperature end. The radiation heat leakage calculation formula is as follows:

[0068]

[0069] Among them, Q rad is the radiation heat transfer; ε1 is the emissivity of the radiated object; ε2 is the emissivity of the radiating object; A1 is the area of ​​the radiated object; T1 is the temperature of the radiated object; A2 is the area of ​​the radiating object; T2 is the temperature of the radiating 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 low-temperature container 2. According to the results of previous studies, a large amount of heat leakage comes from heat conduction. Therefore, the design is mainly focused on the support heat transfer structure and key optimization is carried out. Five-point type, cross type, field type, and honeycomb type have been tried. After comprehensively considering factors such as conduction heat leakage, structural stress, and structural lightweight, it is decided to use a honeycomb support structure to reduce the heat transfer area to achieve the effect of reducing heat leakage.

[0071] Although the initial five-point support structure has the least conduction heat leakage, the local stress is too large and there is a possibility of support column fracture, so it is considered to increase the cross-sectional area. The cross-sectional area of ​​the field type is smaller than that of the cross type, and the volume is reduced by two times, and the stress is reduced by half, and there is no stress concentration at the edge of the cross type. The honeycomb structure has high stability and efficient mechanical properties, and can achieve maximum strength and stiffness with the minimum material usage. Compared with the field type, the stress is reduced by more than two times, and the volume and conduction heat leakage are significantly reduced.

[0072] The material of the supporting heat transfer structure is G-10 fiberglass. The maximum stress of the honeycomb supporting heat transfer structure is 123 MPa, which occurs at the thin-wall top connection connected to the copper box 23. The stress of the remaining parts is less than 100 MPa, which meets the strength requirements of G-10 fiberglass. Figure 7 This is the deformation distribution diagram of the thin-walled low-temperature support. It can be seen that the deformation mainly occurs at the top of the thin wall. At the same time, the stress here is also relatively large, with a maximum value of 0.278mm. The deformation is within the allowable range.

[0073] For the honeycomb support heat transfer structure, considering that the internal space of the thin wall cannot be evacuated smoothly, it is necessary to drill holes in the thin wall support. The size of the hole should be as large as possible while meeting the strength check. This can also reduce the conduction heat leakage to a certain extent. Therefore, an equivalent stress is applied to the honeycomb support heat transfer structure, and then a parametric scan is used to change the aperture size from 4mm to 20mm to obtain the stress condition of the honeycomb support heat transfer structure under different aperture sizes, and the maximum aperture is selected while meeting the strength check. Figure 8 As shown, Figure 8 The stress cloud diagram of the honeycomb support heat transfer structure with a hole diameter of 16 mm is shown. It can be seen from the figure that, under the premise of meeting the strength requirement, 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] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A conduction-cooled superconductor cryogenic container, characterized in that: include: A refrigerator (1), the refrigerator (1) being fixedly connected to the bottom of a body of the maglev train, the refrigerator (1) comprising a cold head and a cold conducting column (11); and A cryogenic container (2), the cryogenic container (2) comprising an outer cavity (21), a superconducting block (22), a copper box (23), and a honeycomb supporting heat transfer structure (24), the outer cavity (21) comprising a cover plate (211) and a rectangular cavity (212) fixedly connected to each other, the interior of the outer cavity (21) being a vacuum environment, the refrigerator (1) being fixedly arranged on the side of the outer cavity (21), the cover plate (211) being fixedly connected to the bottom of a body of a 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 block (22) is fixedly arranged inside the copper box (23), the cold head cooling column (11) passes through the through hole of the side wall of the outer cavity (21) and contacts the copper box (23), and the honeycomb supporting heat transfer structure (24) is arranged between the copper box (23) and the cover plate (211).

2. The conduction-cooled superconductor cryogenic container according to claim 1, characterized in that: 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 block (22), the superconducting block (22) is fixedly arranged in the groove, and the depth of the groove is greater than or equal to the installation height of the superconducting block (22).

3. The conduction-cooled superconductor cryogenic container according to claim 2, characterized in that: The superconducting bulk material (22) is bonded in the groove.

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

5. The conduction-cooled superconductor cryogenic container according to claim 1, characterized in that: The cryogenic container (2) further comprises a vacuum pump interface (25), a vacuum gauge interface (26) and an 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 interior of the outer cavity (21) via the vacuum pump interface (25); the vacuum gauge interface (26) is used to connect a vacuum gauge, and the aviation plug interface (27) is used to connect an aviation plug.

6. The conduction-cooled superconductor cryogenic container according to claim 1, characterized in that: The low-temperature container (2) comprises 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 superconductor cryogenic container according to claim 1, characterized in that: The honeycomb supporting heat transfer structure (24) comprises a rectangular thin wall (241) and a hexagonal thin wall (242), wherein the hexagonal thin wall (242) is arranged inside the rectangular thin wall (241), and each corner of the hexagonal thin wall (242) extends a straight reinforcing rib (243), and one end of each straight reinforcing rib (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 provided on each surface of the rectangular thin wall (241) and the hexagonal thin wall (242).

9. The conduction-cooled superconductor cryogenic container according to claim 1, characterized in that: The material of the honeycomb-shaped supporting heat transfer structure (24) is G-10 glass fiber reinforced plastic.

10. A method for designing a honeycomb heat transfer structure for a conduction-cooled superconductor cryogenic container, characterized in that: The method uses the conduction-cooled superconductor cryogenic container according to any one of claims 1 to 9, and the method comprises: Obtaining the cooling output of the refrigerator (1), the physical parameters and design allowable values ​​of the honeycomb support heat transfer structure (24), wherein the physical parameters include the thermal conductivity and mechanical strength of the material, and the design allowable values ​​include the allowable heat leakage and stress limit; The heat transfer efficiency of the supporting heat transfer structure is calculated according to the cooling output and the thermal conductivity of the material, and a preliminary supporting structure model is obtained by modeling based on the heat transfer efficiency and the design allowable value; Optimizing 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, respectively optimizing the size, wall thickness and rib (243) distribution of the honeycomb unit to obtain an optimized design solution; According to the optimization design scheme, numerical simulation processing is performed, and by applying equivalent stress and parametric scanning analysis, the stress distribution of the honeycomb support heat transfer structure (24) with different pore sizes is obtained; Perform strength verification processing according to the stress distribution to obtain a hole opening scheme that meets the preset structural strength requirements; The final design scheme of the honeycomb support heat transfer structure (24) is obtained by integrating the hole opening scheme and the optimization design scheme.

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