Dual-refrigeration device applied to high-temperature superconducting magnetofluid propulsion

Abstract

The invention provides a double-refrigeration device applied to high-temperature superconducting magnetic fluid propulsion, and relates to the technical field of high-temperature superconducting magnet cooling, the device comprises a magnet Dewar, a magnet liquid nitrogen cylinder, a fixing assembly and a conduction refrigeration system; the magnet liquid nitrogen cylinder is located in the magnet Dewar, one end of the fixing assembly is fixed to the side portion of the magnet liquid nitrogen cylinder, and the other end of the fixing assembly is fixed to the magnet Dewar; dewar protrusions are arranged on the circumferential side wall of the magnet Dewar, and the conduction refrigeration system is installed on the Dewar protrusions and exchanges heat with the superconducting magnet coil in the magnet liquid nitrogen cylinder. The superconducting magnet coil is also provided with a wiring port. The dual-refrigeration device provided by the invention breaks through the dilemma that the critical current cannot be tested after packaging, the liquid nitrogen cooling unit can independently, quickly and uniformly cool the packaged magnet, and the detachable sealing wiring port is arranged, so that the performance verification after packaging is realized, and the quality blind area is eliminated.

Description

Technical Field

[0001] This invention relates to the field of high-temperature superconducting magnet cooling technology, specifically to a dual-cooling device for high-temperature superconducting magnetohydrodynamic propulsion using both conductive cooling and liquid nitrogen cooling. Background Technology

[0002] Magnetohydrodynamic (MHD) propulsion is a novel ship propulsion technology that utilizes strong magnetic and electric fields to generate thrust from seawater. Its core component is a superconducting magnet that generates this strong magnetic field. High-Temperature Superconducting (HTS) materials, such as REBCO (yttrium barium copper oxide) tapes, significantly reduce the operating and maintenance costs of superconducting magnets due to their high critical temperatures (typically in the liquid nitrogen temperature range, above 77K). A key bottleneck that has long remained unresolved in the manufacturing and maintenance of superconducting MHD thrusters is the performance verification and non-destructive testing of the final packaged superconducting magnet. Among these tests, the critical current (Ic) test is the gold standard for assessing whether a superconducting magnet meets design specifications and whether it exhibits manufacturing defects (such as localized damage or excessive joint resistance). However, existing superconducting magnet systems based on a single cooling method have an inherent structural weakness: they are designed for operation rather than testing, resulting in "encapsulation meaning performance black box". Once the magnet is permanently sealed in a vacuum Dewar or cryogenic container, it becomes extremely difficult to perform effective liquid nitrogen temperature critical current testing.

[0003] Currently, there are two main cooling methods for the superconducting magnets in the HTS-MHD propulsion system: liquid nitrogen immersion cooling and conductive cooling. For pure liquid nitrogen immersion systems: Although a stable environment of 77K can be provided, the magnet is permanently encapsulated within the Dewar. Its current and voltage measurement leads are solidified into the internal structure, making it impossible to easily and reliably connect to external high-current test sources and high-precision voltage measurement devices. Forcibly modifying the interface would compromise the vacuum insulation integrity of the Dewar, introducing unacceptable risks.

[0004] For purely conductive refrigeration systems: the cooling capacity of their refrigerators is typically designed only for the heat load required to "maintain" steady-state operation, lacking the enormous sensible heat cooling capacity needed to rapidly cool the magnet from room temperature to the liquid nitrogen temperature range. Even if slow cooling is possible, the refrigerator's cooling efficiency is low in the 77K temperature range, making it difficult to stably maintain the large-scale, uniform temperature field required for testing, thus failing to provide reliable environmental conditions for accurate IC testing. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a dual-cooling device for high-temperature superconducting magnetohydrodynamic propulsion.

[0006] A dual-cooling device for high-temperature superconducting magnetohydrodynamic propulsion, according to the present invention, comprises: Liquid nitrogen immersion cooling system and conduction refrigeration system; The liquid nitrogen immersion cooling system includes a magnetic Dewar, a magnetic liquid nitrogen cylinder, and a fixing assembly; the magnetic liquid nitrogen cylinder is located inside the magnetic Dewar, and one end of the fixing assembly is fixed to the side of the magnetic liquid nitrogen cylinder, and the other end is fixed to the magnetic Dewar; The magnet has a Dewar protrusion on its circumferential sidewall, and the conductive cooling system is installed on the Dewar protrusion to exchange heat with the superconducting magnet coil inside the liquid nitrogen cylinder of the magnet; the superconducting magnet coil is also provided with a wiring port.

[0007] Preferably, the magnetic liquid nitrogen cylinder is provided with magnetic liquid nitrogen cylinder sealing plates at both ends. The magnetic liquid nitrogen cylinder sealing plates are provided with threaded holes and positioning holes. The fixing assembly is fixed to the end of the magnetic liquid nitrogen cylinder through the threaded holes and positioning holes.

[0008] Preferably, it further includes a magnetic cooling screen, which is located between the magnetic Dewar and the magnetic liquid nitrogen cylinder, surrounding the magnetic liquid nitrogen cylinder; the magnetic cooling screen is fixed to the fixing assembly; The magnet cold screen is fixed by a cold screen outer surface fixing seat and a cold screen inner surface fixing seat, and then fixed by a cold screen support epoxy nut; the cylinder of the magnet cold screen has holes for the fixing components to pass through.

[0009] Preferably, the conductive cooling system includes a conductive refrigerator, a secondary cold head, a secondary cold-conducting plate, a flexible connection assembly, and a magnet cold-conducting plate. The secondary cold head is located in the middle of the superconducting magnet coil. Multiple secondary cold-conducting plates are provided, one of which is fixed to the secondary cold head. Adjacent secondary cold-conducting plates are connected through the flexible connection assembly. The secondary cold-conducting plates are fixedly connected to the magnet cold-conducting plate installed on the superconducting magnet coil.

[0010] Preferably, the secondary cooling plate is made of oxygen-free copper, and the flexible connection assembly is composed of multiple layers of copper foil.

[0011] Preferably, the Dewar protrusion includes a Dewar mounting side plate and a Dewar mounting top plate, a cold head mounting flange is provided on the Dewar mounting top plate, the conductive refrigeration unit is mounted on the cold head mounting flange, and the cold head of the conductive refrigeration unit is located inside the Dewar protrusion.

[0012] Preferably, the liquid nitrogen cylinder of the magnet is provided with a liquid nitrogen cylinder heat sink, which is connected to the liquid nitrogen cylinder of the magnet and the superconducting magnet coil respectively, and two adjacent liquid nitrogen cylinder heat sinks are connected by wires.

[0013] Preferably, the magnet dewar is provided with a vacuum port, and the dewar protrusion is provided with a liquid nitrogen pouring port that communicates with the liquid nitrogen cylinder of the magnet.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The dual cooling device provided by this invention overcomes the predicament of not being able to test the critical current after packaging. The liquid nitrogen cooling unit can independently and quickly and uniformly cool the packaged magnet to the 77K test temperature range. The detachable sealed connection port allows for external equipment to be connected during testing and can be restored to a sealed state after testing, realizing the verification of superconducting performance after packaging and eliminating the quality blind spot.

[0015] 2. This invention utilizes dual refrigeration synergy and complementarity. Conductive refrigeration consumes no refrigerant, making it suitable for long-term ship voyages. Liquid nitrogen cooling can quickly remove the heat from large thermal disturbances in the magnet, avoiding overheating and ensuring both long-term operational stability and adaptability to extreme conditions. Attached Figure Description

[0016] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the overall dual-refrigeration device in this invention; Figure 2 This is a schematic diagram of the liquid nitrogen refrigeration system in this invention; Figure 3 This is a partial schematic diagram highlighting the fixing component in this invention; Figure 4 This is a schematic diagram showing the structural relationship between the magnetic liquid nitrogen cylinder and the fixing assembly in this invention; Figure 5 This is a schematic diagram of the internal structure of the Dewar protrusion in this invention; Figure 6 This is a schematic diagram of the conductive cooling system structure in this invention; Figure 7 This is a partial schematic diagram of the magnet Dewar in this invention.

[0017] Explanation of reference numerals in the attached figures: Detailed Implementation

[0018] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0019] Example 1 This invention provides a dual-cooling device for high-temperature superconducting magnetohydrodynamic propulsion, combining conductive cooling and liquid nitrogen cooling. The structure of this device is as follows: Figure 1As shown, the superconducting magnet coil 3 in this device has two cooling methods: 1. Liquid nitrogen immersion cooling, which can calculate the critical current of the magnet coil at 4.2K by testing the critical current of the coil under liquid nitrogen conditions, thus reducing testing costs. 2. During normal operation, the superconducting magnet coil 3 can be cooled by conduction using a KDE412SA refrigerator.

[0020] As a core component of the cooling device, the liquid nitrogen immersion cooling system achieves efficient cooling by utilizing the latent heat of phase change of liquid nitrogen (boiling point 77K). Its hardware structure must meet core requirements such as low-temperature storage, precise transmission, uniform cooling, and safety control.

[0021] The liquid nitrogen immersion cooling system mainly consists of the following components from the inside out: a magnetic liquid nitrogen cylinder 1, a magnetic cooling screen 4, and a magnetic Dewar 2.

[0022] The magnetic liquid nitrogen cylinder 1 is suspended inside the magnetic Dewar 2 via a precision fixing assembly system. For example... Figure 2 , Figure 3 and Figure 4 As shown, the fixing assembly mainly includes a titanium alloy tie rod 6 and an epoxy tie rod 5. The specific installation method is as follows: On the liquid nitrogen cylinder sealing plates 11 at both ends of the magnetic liquid nitrogen cylinder 1, there are two titanium alloy tie rod bases 61 and two epoxy tie rod bases 51 respectively. The titanium alloy tie rods 6 and epoxy tie rods 5 are respectively hinged to the corresponding bases.

[0023] Each base has a positioning hole 8 and a threaded hole 7 machined on the liquid nitrogen cylinder sealing plate 11. During installation, the base is first positioned precisely by engaging the positioning pin with the positioning hole 8, and then fasteners (such as hex socket screws) are used to engage the threaded hole 7 to secure it firmly.

[0024] Correspondingly, a slanted base 52, hinged to the epoxy tie rod 5, is provided on the inner side of the curved surface of the magnet Dewar 2, and a titanium alloy tie rod tail seat 62 is provided on the outer side of the curved surface of the magnet Dewar 2. After the titanium alloy tie rod 6 penetrates the wall plate of the magnet Dewar 2, it is fixed by the titanium alloy tie rod tail seat 62 and a preload is applied.

[0025] Ultimately, after all the tie rods are installed, the epoxy tie rod 5 mainly bears the axial compressive force, while the titanium alloy tie rod 6 mainly bears the axial tensile force. This composite fixing assembly makes full use of the high strength and high rigidity of the titanium alloy and the extremely low thermal conductivity and thermal shrinkage of the epoxy tie rod, so as to meet the huge electromagnetic force support requirements while minimizing heat leakage from the room temperature environment to the cryogenic magnetic liquid nitrogen cylinder 1.

[0026] The purpose of using titanium alloy tie rod 6 is to utilize its high strength, high stiffness, and extremely low thermal conductivity to withstand enormous mechanical loads, while minimizing heat transfer from room temperature to the cryogenic end. This meets the requirements for mechanical reliability and resistance to enormous electromagnetic forces.

[0027] The purpose of using epoxy tie rods (typically glass fiber or carbon fiber impregnated with epoxy resin and then cured) is to utilize the extremely high specific strength (strength / density) and near-zero thermal shrinkage of the composite material, while also having extremely low thermal conductivity. This meets the requirements for reducing operating energy consumption (cooling power consumption) and precisely managing low-temperature thermal stress.

[0028] To reduce radiative heat transfer, a magnetic cooling shield 4 is installed between the magnetic Dewar 2 and the magnetic liquid nitrogen cylinder 1. The magnetic cooling shield 4 has a cylindrical structure, and the entire magnetic liquid nitrogen cylinder 1 is enclosed by the magnetic cooling shield 4. The magnetic cooling shield 4 provides an effective thermal barrier for the superconducting magnetic coil 3, protecting it from the influence of high-temperature components such as the vacuum chamber and the Dewar.

[0029] The installation method for magnet cooling screen 4 is as follows: Figure 3 As shown, one end of the titanium alloy tie rod 6 is connected to the titanium alloy tie rod base 61 on the magnetic liquid nitrogen cylinder sealing plate 11, and the other end is connected to the magnetic Dewar 2 through the titanium alloy tie rod tail seat 62, ensuring the overall connection of the magnetic liquid nitrogen cylinder 1 is stable. The magnetic cold screen 4 is fixed vertically by the cold screen outer surface fixing seat 41 and the cold screen inner surface fixing seat 42, and then limited and fixed by the cold screen support epoxy nut 43, thereby fixing the cold screen to the titanium alloy tie rod 6. The epoxy tie rod 5 and the titanium alloy tie rod 6 pass through the cold screen by drilling holes in the cold screen outer cylinder and the cold screen end cap.

[0030] The magnet Dewar 2 itself is a high-vacuum heat-insulating structure, and a vacuum port 106 is provided at one end (see...). Figure 7 This is used to evacuate the system to a high vacuum before operation, thereby greatly reducing the heat load caused by gas convection and conduction.

[0031] The superconducting magnet coil 3 is installed inside the liquid nitrogen cylinder 1. Specifically, the liquid nitrogen cylinder 1 includes a coaxially arranged inner cylinder 12, an outer cylinder 13, and liquid nitrogen sealing plates 11 at both ends. A circular through hole is opened in the center of the liquid nitrogen sealing plate 11. After assembly, the circular through holes on the two liquid nitrogen sealing plates 11 are respectively connected to the two ends of the inner cylinder 12, and the outer circumferences of the two liquid nitrogen sealing plates 11 are respectively connected to the two ends of the outer cylinder 13. The inner cylinder 12, the outer cylinder 13, and the liquid nitrogen sealing plates 11 at both ends form an annular sealed space for holding liquid nitrogen and completely immersing the superconducting magnet coil 3.

[0032] The steps for installing the superconducting magnet coil 3 into the liquid nitrogen cylinder 1 are as follows: The superconducting magnet coil 3 is assembled in series using modular components and installed horizontally. First, the inner cylinder 12 of the liquid nitrogen cylinder passes through the center of the magnet system and is then placed inside the outer cylinder 13 of the liquid nitrogen cylinder. Two coil pull rods 66 are provided at each of the two ends of the superconducting magnet coil 3. The four coil pull rods 66 are connected to the outer cylinder 13 of the liquid nitrogen cylinder. Finally, the liquid nitrogen cylinder sealing plate 11 is assembled. In a preferred embodiment, the coil pull rods are made of titanium alloy.

[0033] The magnet cooling screen 4 includes a cooling screen inner cylinder 44 and a cooling screen outer cylinder 46 arranged coaxially, and cooling screen cover plates 45 located at both ends; the cooling screen inner cylinder 44 passes through the center of the liquid nitrogen cylinder inner cylinder 12, and the cooling screen inner cylinder 44, cooling screen outer cylinder 46 and cooling screen cover plates 45 together surround the magnet system.

[0034] The magnet Dewar 2 includes an inner Dewar cylinder 21, an outer Dewar cylinder 22, and a Dewar end cap 23. The inner Dewar cylinder 21 passes through the center of the inner cylinder 44 of the cold screen. The inner Dewar cylinder 21, the outer Dewar cylinder 22, and the Dewar end cap 23, when combined, surround the magnet cold screen 4.

[0035] The superconducting magnet coil 3 is provided with a wiring port, which is connected to the wire in the superconducting magnet coil 3 for experimental testing.

[0036] A Dewar protrusion 9, approximately rectangular in size, is formed on the outer cylinder 22 of the magnet Dewar 2 by stamping or welding. A conductive cooling system is mounted on this protrusion 9. Specifically, refer to... Figure 5 As shown, the Dewar protrusion 9 includes a Dewar mounting side plate 91 and a Dewar mounting top plate 92. A cold head mounting flange is installed on the Dewar mounting top plate 92. The conductive refrigeration unit 100 (preferably a GM refrigeration unit in this embodiment) is fixed to the Dewar protrusion 9 through the flange, and its cold head extends into the internal space of the Dewar protrusion 9. The conductive refrigeration unit 100 is connected to the superconducting magnet coil 3 through a secondary heat conduction assembly to achieve heat exchange.

[0037] The specific path structure of conduction cooling is as follows: Figure 6 As shown, the secondary cooling assembly includes a secondary cold head 101 and a secondary cooling plate 102. The secondary cold head 101, connected to the conductive refrigerator 100, serves as the cold source and is positioned close to the center of the superconducting magnet coil 3 to optimize temperature distribution. A secondary cooling plate 102 (preferably made of oxygen-free copper with high thermal conductivity) is fixed on the secondary cold head 101. To accommodate thermal expansion and contraction and ensure good thermal contact, multiple secondary cooling plates 102 arranged along the coil axis are connected in series using a flexible connection assembly 103 composed of multiple layers of thin copper foil. Finally, these secondary cooling plates 102 are tightly connected to the magnet cooling plate 108 pre-installed on the superconducting magnet coil 3 by screws, thereby efficiently conducting the cooling energy to the coil body.

[0038] Multiple liquid nitrogen heat sinks 104 are installed on the liquid nitrogen cylinder 1, which are connected to the liquid nitrogen cylinder 1 and the superconducting magnet coil 3 respectively. Their function is to conduct the heat generated by the superconducting magnet coil 3 away from the device and dissipate it into the surrounding environment through thermal conductivity, which is beneficial for uniform cooling. Figure 7 As shown, the two liquid nitrogen cylinder heat sinks 104 are connected by copper wire soldering for auxiliary cooling, which helps to uniformly cool the magnet system and the liquid nitrogen cylinder 1. This design is for cooling under full load of 10 magnet coils. Depending on different working conditions, the number of coils can be matched from 1 to 10, and the cooling time will be greatly reduced compared to full load.

[0039] Since a window needs to be opened on the circumferential side wall of the magnetic liquid nitrogen cylinder 1 for the connection of the conductive refrigeration system, a liquid nitrogen cylinder cold shield 105 is installed between the window and the conductive refrigeration system to prevent this from becoming a heat leakage bottleneck. This cold shield is a protruding part of the outer cylinder 46 of the cold shield, which can both conduct cold and effectively block radiant heat, reducing the evaporation of liquid nitrogen from this point.

[0040] A liquid nitrogen pouring port 107 is also provided on the top plate 92 of the Dewar installation. The liquid nitrogen pouring port 107 is connected to the inside of the liquid nitrogen cylinder through a pipe to realize the filling of liquid nitrogen.

[0041] Working principle: The working process of this dual-cooling unit can be divided into two modes according to requirements: Performance testing mode: Turn off the conductive chiller 100, and add liquid nitrogen into the liquid nitrogen cylinder 1 of the magnet through the liquid nitrogen pouring port 107. After the superconducting magnet coil 3 has been fully and uniformly cooled to 77K and stabilized, open the wiring port and connect the external test circuit. Then, slowly apply an increasing current while monitoring the coil voltage to accurately determine its critical current value. After the test is completed, remove the external leads and seal the wiring port.

[0042] Long-term operation mode: Empty or retain a small amount of liquid nitrogen as needed, primarily starting the conduction chiller 100. The cooling capacity generated by the chiller continuously removes the heat generated by the superconducting magnet coil 3 during operation through the aforementioned conduction path, maintaining it at the low temperature required for superconductivity. This mode is particularly suitable for long-term voyages of ships, avoiding the inconvenience of frequent liquid nitrogen replenishment. In the event of a sudden large heat load, liquid nitrogen can be quickly injected to utilize its enormous latent heat for emergency cooling, preventing the magnet from losing superconductivity.

[0043] Example 2 This embodiment is basically the same in structure as Embodiment 1, the main difference being that the number of superconducting magnet coils 3 can be configured according to the power requirements of the thruster. The number of the conductive cooling system (especially the number of the secondary cooling plate 102 and the flexible connection assembly 103) and the number of the magnet liquid nitrogen cylinder heat sink 104 can be adjusted accordingly between 1 and 10. For example, for low-power applications, a single coil and a corresponding simplified conductive cooling structure can be used, in which case the cooling time of the refrigerator will be significantly shorter than that of the full-load configuration (10 coils).

[0044] Example 3 Based on Examples 1 and 2, this embodiment further optimizes the workflow and control strategy of the dual refrigeration device, and proposes a hybrid working mode of partial liquid nitrogen precooling + conduction refrigeration as the main maintenance, which is suitable for application scenarios with higher requirements for system start-up speed and temperature uniformity.

[0045] In this embodiment, the dual cooling device also includes a liquid nitrogen spraying auxiliary system, which consists of a liquid nitrogen spraying pipe, a solenoid valve, and a temperature sensor. The liquid nitrogen spraying pipe is arranged above the inside of the magnet liquid nitrogen cylinder (1), with multiple spraying holes evenly distributed along the axial direction. The solenoid valve is installed on the pipeline before the liquid nitrogen pouring port (107), and the temperature sensor is arranged at key positions (such as the end and middle) of the superconducting magnet coil (3).

[0046] The workflow is as follows: S1. Start-up phase: When the system needs to be cooled rapidly from room temperature to around 77K, the conduction chiller (100) is started first, and a small amount of liquid nitrogen is sprayed into the liquid nitrogen cylinder (1) of the magnet through the liquid nitrogen spraying system. The liquid nitrogen quickly vaporizes and absorbs heat, thereby achieving rapid and uniform precooling of the superconducting magnet coil (3).

[0047] S2. Switching judgment: When the temperature sensor detects that the overall temperature of the coil has dropped to the range of 80K to 85K, the control system closes the solenoid valve and stops the liquid nitrogen spraying.

[0048] S3. Main operation phase: After this, the conductive cooling system takes over completely, continuing to cool the coil to the target operating temperature (e.g., 20K~30K) and maintaining it in this temperature range for a long time.

[0049] S4 Emergency Mode: If an abnormal increase in local temperature is detected during operation (such as due to a sudden heat load), liquid nitrogen spray can be briefly activated again to achieve rapid and fixed-point temperature control of the coil and avoid overload.

[0050] Liquid nitrogen spray precooling significantly shortens the time it takes for the system to cool from room temperature to operating temperature, overcoming the slow cooling speed of pure conduction refrigeration systems at high temperatures. Only a small amount of liquid nitrogen is used in the most energy-intensive initial cooling stage, while conduction refrigeration remains the primary method during long-term operation, reducing liquid nitrogen consumption. At the same time, automated process control is achieved through sensors and valves.

[0051] This device overcomes the structural shortcoming of other devices that cannot test the critical current of coils in the liquid nitrogen temperature range after packaging, as detailed below.

[0052] Provides a testing environment: The liquid nitrogen immersion cooling system can work independently, utilizing the huge latent heat of liquid nitrogen to quickly and efficiently cool the magnet encapsulated in the magnet Dewar to the standard test temperature range of 77K, perfectly simulating the low temperature environment required for IC testing.

[0053] Test interface retained: This device was designed with testing needs in mind from the outset. During the testing phase, the current and voltage tap leads can be connected to external devices via a detachable, sealed interface. After testing, the system can be restored to a completely sealed operating state without affecting its integrity or reliability.

[0054] Achieving closed-loop performance verification: This enables manufacturers and users to directly verify 100% of the core performance indicators (critical current) after the product is finally packaged and before delivery, ensuring "what you see is what you get" and completely eliminating quality blind spots. This is revolutionary for ensuring the reliability and safety of superconducting magnetohydrodynamic thrusters.

[0055] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0056] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A dual-cooling device for high-temperature superconducting magnetohydrodynamic propulsion, characterized in that, include: Liquid nitrogen immersion cooling system and conduction refrigeration system; The liquid nitrogen immersion cooling system includes a magnetic Dewar (2), a magnetic liquid nitrogen cylinder (1), and a fixing assembly; The magnetic liquid nitrogen cylinder (1) is located inside the magnetic Dewar (2). One end of the fixing component is fixed to the side of the magnetic liquid nitrogen cylinder (1), and the other end is fixed to the magnetic Dewar (2). The magnet Dewar (2) has a Dewar protrusion (9) on its circumferential sidewall. The conductive cooling system is installed on the Dewar protrusion (9) and exchanges heat with the superconducting magnet coil (3) inside the magnet liquid nitrogen cylinder (1). The superconducting magnet coil (3) is also provided with a wiring port.

2. The dual-cooling device for high-temperature superconducting magnetohydrodynamic propulsion according to claim 1, characterized in that, The magnetic liquid nitrogen cylinder (1) is provided with magnetic liquid nitrogen cylinder sealing plates (11) at both ends. The magnetic liquid nitrogen cylinder sealing plates (11) are provided with threaded holes (7) and positioning holes (8). The fixing components are fixed to the ends of the magnetic liquid nitrogen cylinder (1) through the threaded holes (7) and positioning holes (8).

3. The dual-cooling device for high-temperature superconducting magnetohydrodynamic propulsion according to claim 1, characterized in that, It also includes a magnet cooling screen (4), which is located between the magnet Dewar (2) and the magnet liquid nitrogen cylinder (1) and surrounds the magnet liquid nitrogen cylinder (1); the magnet cooling screen (4) is fixed on the fixing assembly; The magnet cold screen (4) is fixed by the outer surface fixing seat (41) and the inner surface fixing seat (42), and then limited and fixed by the cold screen support epoxy nut (43); the cylinder of the magnet cold screen (4) has a hole for the fixing component to pass through.

4. The dual-cooling device for high-temperature superconducting magnetohydrodynamic propulsion according to claim 1, characterized in that, The conductive cooling system includes a conductive refrigerator (100), a secondary cold head (101), a secondary cooling plate (102), a flexible connection assembly (103), and a magnet cooling plate (108). The secondary cold head (101) is located in the middle of the superconducting magnet coil (3). There are multiple secondary cooling plates (102), one of which is fixed to the secondary cold head (101). Adjacent secondary cooling plates (102) are connected by the flexible connection assembly (103). The secondary cooling plates (102) are fixedly connected to the magnet cooling plate (108) installed on the superconducting magnet coil (3).

5. The dual-cooling device for high-temperature superconducting magnetohydrodynamic propulsion according to claim 4, characterized in that, The secondary cooling plate (102) is made of oxygen-free copper, and the flexible connection component (103) is composed of multiple layers of copper foil.

6. The dual-cooling device for high-temperature superconducting magnetohydrodynamic propulsion according to claim 1, characterized in that, The Dewar protrusion (9) includes a Dewar mounting side plate (91) and a Dewar mounting top plate (92). A cold head mounting flange is provided on the Dewar mounting top plate (92). The conductive refrigeration unit (100) is installed on the cold head mounting flange, and the cold head of the conductive refrigeration unit (100) is located inside the Dewar protrusion (9).

7. The dual-cooling device for high-temperature superconducting magnetohydrodynamic propulsion according to claim 1, characterized in that, The liquid nitrogen cylinder (1) is provided with a liquid nitrogen cylinder heat sink (104), which is connected to the liquid nitrogen cylinder (1) and the superconducting magnet coil (3) respectively. Two adjacent liquid nitrogen cylinder heat sinks (104) are connected by wires.

8. The dual-cooling device for high-temperature superconducting magnetohydrodynamic propulsion according to claim 1, characterized in that, The magnet Dewar (2) is provided with a vacuum port (106), and the Dewar protrusion (9) is provided with a liquid nitrogen pouring port (107) that is connected to the magnet liquid nitrogen cylinder (1).

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