Composite material conductively cooled skeletons for low-loss fast-pulsed arc magnets

Abstract

This disclosure provides a composite material conductive cooling frame for a low-loss fast-pulse arc magnet, comprising: a frame body, the frame body being composed of carbon fiber composite material with a predetermined thermal conductivity, the frame body having an arc-shaped structure; a frame groove disposed on the surface of the frame body, the frame groove being used to install the excitation coil of the low-loss fast-pulse arc magnet; and a frame inner wall disposed on the inner side of the frame body facing the excitation coil, the frame inner wall being composed of carbon fiber composite material with a predetermined resistivity.

Description

Technical Field

[0001] This disclosure relates to the field of superconducting magnet technology, and more particularly to a composite material conductive cooling frame for low-loss fast-pulse arc magnets. Background Technology

[0002] When an arc-shaped magnet that can generate a rapidly changing strong magnetic field is in operation, a high-frequency pulse current with a large peak value will be passed through the excitation coil, which can cause some problems.

[0003] Traditional metal magnet frames (usually made of stainless steel or aluminum) generate significant eddy current effects in changing magnetic fields. This not only causes huge energy losses, but also leads to a sharp rise in the temperature of the frame and coil due to Joule heating, causing magnet quenching, and in severe cases, insulation failure or structural damage.

[0004] Large magnet systems require high rigidity and strength of the supporting structure. However, traditional metal frames need to be cut to control the heat generated by eddy current losses, which poses a risk of reduced frame strength at the joints. Summary of the Invention

[0005] In view of this, the present disclosure provides a composite material conductive cooling frame for a low-loss fast-pulse arc magnet, which at least partially solves the problems of high loss and high heat load caused by eddy current effect in metal frames in fast-pulse arc magnets, as well as the structural strength weakening caused by cutting the frame to control eddy current.

[0006] This disclosure provides a composite material conductive cooling frame for a low-loss fast-pulse arc magnet, comprising: a frame body, the frame body being composed of carbon fiber composite material with a predetermined thermal conductivity, the frame body having an arc-shaped structure; a frame groove disposed on the surface of the frame body, the frame groove being used to install the excitation coil of the low-loss fast-pulse arc magnet; and a frame inner wall disposed on the inner side of the frame body facing the excitation coil, the frame inner wall being composed of carbon fiber composite material with a predetermined resistivity.

[0007] According to an embodiment of this disclosure, the skeleton groove is a G10 groove formed by processing G10 material and conforming to the winding path of the excitation coil. The G10 groove is fixed to the surface of the skeleton body by material curing.

[0008] According to embodiments of this disclosure, a metal cooling channel is also formed along the radial direction of the skeleton body; the composite material conductive cooling skeleton further includes a metal cold-conducting plate, which is tightly fitted to the inner wall of the metal cooling channel; wherein, the cold head of the external cryogenic refrigerator is directly thermally connected to the metal cold-conducting plate through a cryogenic connector, and the cold energy is introduced into the interior of the composite material conductive cooling skeleton; the heat generated by the excitation coil is transferred to the inner wall of the skeleton and the metal cold-conducting plate through the G10 wire groove, and is discharged through the metal cold-conducting plate.

[0009] According to embodiments of this disclosure, the skeleton groove, the metal cooling plate, and the skeleton body are integrated into a non-removable integral structure through integral casting.

[0010] According to embodiments of this disclosure, the metal cold-conducting plates are arranged in segments along the arc-shaped skeleton body, and the metal cold-conducting plates are made of a material with high thermal conductivity.

[0011] According to embodiments of this disclosure, the skeleton groove is a groove formed by directly machining the surface of the skeleton body to conform to the winding path of the excitation coil.

[0012] According to an embodiment of this disclosure, a metal channel is formed along the radial direction of the skeleton body. The wall of the skeleton groove and the inner wall of the skeleton are in close contact with the metal channel. The heat generated by the excitation coil is directly transferred to the metal channel through the wall of the skeleton groove.

[0013] According to embodiments of this disclosure, it further includes: a conductive cooling structure, nested or padded between multiple excitation coils, for forming a secondary heat transport channel in the axial direction of the skeleton body, wherein the conductive cooling structure and the metal cooling channel or metal channel constitute a multi-level, three-dimensional cooling network.

[0014] According to embodiments of this disclosure, the conductive cooling structure includes a cooling ring or a cooling strip.

[0015] The composite material conductive cooling frame for low-loss fast-pulse arc magnets disclosed herein has at least the following technical effects.

[0016] Using carbon fiber composite material with good thermal conductivity as the main material of the superconducting magnet skeleton significantly improves the magnet's cooling efficiency. Using high-resistivity fiber-reinforced composite material as the inner wall of the skeleton effectively reduces eddy current losses within the skeleton itself, thus avoiding the problem of induced eddy currents generated within the skeleton itself in rapidly changing magnetic fields. This significantly reduces the risk of magnet overheating caused by heat generated by the skeleton itself, maintaining structural integrity to withstand high stress. Unlike metal skeletons, which require slotting or segmentation to suppress eddy currents, the composite skeleton can be designed as a complete, integral structure, fully utilizing the excellent strength of the composite material. It can reliably withstand the enormous pulsed electromagnetic forces generated by fast-pulse, strong magnetic fields, offering a high safety margin.

[0017] By embedding a high thermal conductivity metal plate within the composite material body, a low thermal resistance radial heat transfer main channel is established within the skeleton, extending directly from the cold head of the refrigerator to the vicinity of the inner layer of the coil, thus constructing an efficient embedded radial conduction cooling path. This design enables cold energy to reach the vicinity of the heat source (coil) efficiently, significantly improving thermal conductivity and effectively controlling the coil temperature rise.

[0018] Cooling structures are constructed by nesting or padding high thermal conductivity material-based cooling rings or strips between each layer of superconducting coils. These structures obtain cooling through cooling plates or metal frames and establish additional, highly efficient secondary heat transport channels in the axial direction. This structure, in conjunction with the radially thermally conductive metal frame, forms a multi-layered, three-dimensional cooling network that can more quickly equalize interlayer temperature differences. This enhanced design significantly improves the superconducting magnet's ability to withstand instantaneous high heat loads, enabling it to withstand higher pulse rates and stronger magnetic field change rates, effectively improving the magnet's overall performance boundaries. Attached Figure Description

[0019] The foregoing contents, as well as other objects, features, and advantages of this disclosure, will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0020] Figure 1 A schematic radial cross-sectional view of the assembled composite conductive cooling skeleton according to an embodiment of the present disclosure is shown.

[0021] Figure 2 The diagram schematically illustrates a radial cross-sectional view of a composite material conductive cooling skeleton based on a spliced ​​skeleton groove according to an embodiment of the present disclosure after assembly.

[0022] Figure 3 A schematic radial cross-sectional view of the integral wire groove skeleton assembled according to an embodiment of the present disclosure is shown.

[0023] Figure 4 The schematic diagram illustrates the installation of the internal cooling channels of the skeleton according to an embodiment of the present disclosure.

[0024] Figure 5 A schematic diagram of a conductive cooling structure according to an embodiment of the present disclosure is shown.

[0025] Figure 6 A schematic diagram illustrating the comparison of maximum operating temperature rise between carbon fiber composite materials and metal skeletons according to embodiments of the present disclosure is provided. Detailed Implementation

[0026] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0027] To overcome the drawbacks of metal skeletons in fast-pulse arc magnets, such as high losses and high heat loads due to eddy current effects, and structural strength weakening caused by cutting the skeleton to control eddy currents, embodiments of this disclosure provide a composite material conductive cooling skeleton for low-loss fast-pulse arc magnets. By using a composite material and an integrated structural design, the skeleton is constructed from electrically insulating or low-conductivity high-performance fiber-reinforced composite materials. As the core mechanical support structure of the skeleton, its high resistance characteristics ensure that it does not generate significant eddy currents in the pulsed magnetic field. This eliminates eddy current losses within the skeleton itself while ensuring that the skeleton possesses the complete mechanical properties to withstand the electromagnetic forces of fast-pulse, strong magnetic fields, thereby improving the thermal conductivity and reliability of the magnet system.

[0028] Figure 1 A schematic radial cross-sectional view of the assembled composite conductive cooling skeleton according to an embodiment of the present disclosure is shown.

[0029] like Figure 1 As shown, Figure 1 The layered structure of the composite material conductive cooling skeleton is shown. The composite material conductive cooling skeleton may include a skeleton body 101, a skeleton groove 102, and a skeleton inner wall 103.

[0030] The skeleton body 101 is composed of carbon fiber composite material with a predetermined thermal conductivity, and the skeleton body 101 has an arc-shaped structure. The skeleton body 101 can be composed of electrically insulating or low-conductivity high-performance fiber-reinforced composite material, serving as the main structure of the core mechanical support of the composite material conductive cooling skeleton.

[0031] A wire slot 102 is disposed on the surface of the frame body 101, and the wire slot 102 is used to install the excitation coil of the low-loss fast-pulse arc magnet. The wire slot 102 is disposed on the side of the frame body 101 facing the excitation coil.

[0032] The inner wall 103 of the skeleton is located on the inner side of the skeleton body 101 facing the excitation coil, and the inner wall 103 of the skeleton is made of carbon fiber composite material with a predetermined resistivity.

[0033] According to embodiments of this disclosure, the carbon fiber composite material with the predetermined thermal conductivity can be a carbon fiber reinforced epoxy resin composite material. This material possesses high thermal conductivity, which can improve the thermal conductivity of the superconducting magnet's skeleton. Simultaneously, it exhibits high strength and high resistivity. As a core load-bearing structure, its high resistivity ensures that the skeleton body generates almost no eddy currents in a pulsed magnetic field, while also being able to withstand the enormous electromagnetic stress generated by the excitation coil. It should be noted that, within the limits allowed by the manufacturing process, the specific thermal conductivity data is determined by simulation results.

[0034] According to embodiments of this disclosure, the skeleton cable tray can be implemented in various ways, including spliced ​​skeleton cable trays and integral skeleton cable trays.

[0035] Figure 2 The diagram schematically illustrates a radial cross-sectional view of a composite material conductive cooling skeleton based on a spliced ​​skeleton groove according to an embodiment of the present disclosure after assembly.

[0036] like Figure 2 As shown, in some embodiments, the spliced ​​skeleton groove is a G10 groove 121 formed by processing G10 material and conforming to the winding path of the excitation coil. The G10 groove 121 is fixed to the surface of the skeleton body 101 by material curing.

[0037] Because G10 material is relatively easy to process, independent G10 slots 121 can be pre-fabricated using precision machining. The excitation coil is precisely embedded and fixed in the G10 slots 121. The heat generated by the coil during operation is transferred through the G10 slots 121 to the inner wall 103 of the frame and the high thermal conductivity metal cooling plate 104, and is finally discharged by the metal cooling plate 104.

[0038] In some embodiments, in addition to improving the thermal conductivity of the skeleton based on the aforementioned structure, a metal cooling channel is also formed along the radial direction (thickness direction) of the skeleton body. The composite material conductive cooling skeleton also includes a metal cold-conducting plate 104, which is tightly fitted to the inner wall of the metal cooling channel.

[0039] In some embodiments, the skeleton groove 102, the metal cooling plate 104 and the skeleton body 103 are integrated into a non-removable integral structure by integral casting to ensure effective transfer of mechanical loads and stable contact of the thermal interface.

[0040] Figure 3 A schematic radial cross-sectional view of the integral wire groove skeleton assembled according to an embodiment of the present disclosure is shown.

[0041] like Figure 3 As shown, in some embodiments, the skeleton groove 102 is a groove formed by directly machining the surface of the skeleton body 101 to conform to the winding path of the excitation coil.

[0042] A metal channel is formed along the radial direction of the skeleton body. The wall of the skeleton groove and the inner wall of the skeleton are in close contact with the metal channel. The heat generated by the excitation coil is directly transferred to the metal channel through the wall of the skeleton groove.

[0043] For example, the inner wall 103 and the groove 102 of the composite material conductive cooling skeleton are manufactured as a whole, using high thermal conductivity and high strength carbon fiber composite material to ensure both high cooling efficiency and skeleton strength. In its inner region facing the coil, a structure with high thermal conductivity, sufficient mechanical strength and electrical insulation performance is formed by using high thermal conductivity carbon fiber.

[0044] High thermal conductivity metal (such as oxygen-free copper) channels are pre-designed and integrated into the skeleton to form the radial cooling path of the skeleton body 101. These metal channels also achieve effective thermal connection with the external refrigerator cold head.

[0045] The required skeleton grooves are directly formed on the surface of the carbon fiber skeleton body through high-precision machining. The excitation coil is installed in this skeleton groove. The skeleton groove wall, the inner wall of the skeleton, and the integrated metal cooling channel are designed to be in close contact. The heat is conducted from the coil through the skeleton and the groove wall to the cooling channel in a more direct path with lower thermal resistance, achieving a high degree of integration between structure and heat transfer function.

[0046] Figure 4 The schematic diagram illustrates the installation of the internal cooling channels of the skeleton according to an embodiment of the present disclosure.

[0047] like Figure 4 As shown, the metal cold-conducting plate 104, serving as a primary heat transfer interface, can be arranged in segments along the arc-shaped skeleton body, using an intercalation method. The metal cold-conducting plate 104 can be made of a material with high thermal conductivity, such as high-purity aluminum or oxygen-free copper plate. For example, the inner wall of the cooling channel is tightly bonded to a high-purity, high-thermal-conductivity metal plate (such as an oxygen-free copper plate with RRR≥100).

[0048] The cold head of the external cryogenic refrigerator is directly thermally connected to the metal cold conduction plate 104 through a cryogenic connector, so as to introduce the cold energy into the interior of the composite material conductive cooling frame; the heat generated by the excitation coil is transferred to the inner wall 103 of the frame and the metal cold conduction plate 104 through the G10 wire groove, and is discharged through the metal cold conduction plate 103.

[0049] Figure 5 A schematic diagram of a conductive cooling structure according to an embodiment of the present disclosure is shown.

[0050] In some embodiments, the composite material conductive cooling skeleton further includes a conductive cooling structure nested or padded between multiple excitation coils for forming a secondary heat transport channel in the axial direction of the skeleton body 101. The conductive cooling structure and the metal cooling channel or metal channel constitute a multi-level, three-dimensional cooling network.

[0051] Furthermore, the conductive cooling structure includes a cooling strip 105 or a cooling ring 105.

[0052] For example, cooling structures are constructed by nesting or padding with heat-conducting rings or strips made of high thermal conductivity materials such as oxygen-free copper between each layer of excitation coils. These heat-conducting structures obtain cooling through heat-conducting plates or metal skeleton modules and establish additional, efficient secondary heat transport channels in the axial direction. This structure, in conjunction with the radially thermally conductive metal skeleton, forms a multi-level, three-dimensional cooling network that can more quickly equalize interlayer temperature differences. This enhanced design significantly improves the superconducting magnet's ability to withstand instantaneous high heat loads, enabling it to withstand higher pulse rates and stronger magnetic field change rates, effectively improving the magnet's overall performance boundaries.

[0053] Figure 6 A schematic diagram illustrating the comparison of maximum operating temperature rise between carbon fiber composite materials and metal skeletons according to embodiments of the present disclosure is provided.

[0054] like Figure 6 As shown, comparing carbon fiber composite skeletons and metal skeletons with the same thermal conductivity, the metal skeleton was cut to control eddy current loss while ensuring skeleton strength. Even so, the metal skeleton still has eddy current effects. Compared with the carbon fiber composite skeleton with an integral structure, the steady-state temperature rise of the metal skeleton is 1.8K. Therefore, using a carbon fiber skeleton can ensure skeleton strength and effectively control temperature rise.

[0055] Therefore, using carbon fiber, which has good thermal conductivity, as the framework material for superconducting magnets significantly improves the cooling efficiency of the magnets. Using high-resistivity fiber-reinforced composite materials as the inner wall structure of the magnets effectively reduces eddy current losses in the framework itself, thus avoiding the problem of induced eddy currents generated within the framework itself in rapidly changing magnetic fields, and significantly reducing the risk of magnet overheating caused by heat generation from the framework itself.

[0056] To maintain structural integrity and withstand high stress, the composite material skeleton can be designed as a complete monolithic structure without the need for slotting or segmentation as required to suppress eddy currents in metal skeletons. This fully utilizes the excellent strength of composite materials and can reliably withstand the huge pulsed electromagnetic forces generated by fast pulsed strong magnetic fields, with a high safety margin.

[0057] Constructing an efficient embedded radial conduction cooling path: By embedding a high thermal conductivity metal plate within the composite material body, a low thermal resistance radial heat transfer main channel is established within the skeleton, extending directly from the cold head of the refrigerator to the vicinity of the inner layer of the coil. This design enables cooling to reach the vicinity of the heat source (coil) efficiently, significantly improving thermal conductivity and effectively controlling coil temperature rise.

[0058] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A composite material conductive cooling frame for low-loss fast-pulse arc magnets, characterized in that, include: The skeleton body is made of carbon fiber composite material with a predetermined thermal conductivity and has an arc-shaped structure. A skeleton groove is provided on the surface of the skeleton body, and the skeleton groove is used to install the excitation coil of the low-loss fast pulse arc magnet. The inner wall of the skeleton is located on the inner side of the skeleton body facing the excitation coil, and the inner wall of the skeleton is made of carbon fiber composite material with a predetermined resistivity.

2. The composite material conductive cooling frame according to claim 1, characterized in that, The skeleton groove is a G10 groove formed by processing G10 material and conforming to the winding path of the excitation coil. The G10 groove is fixed to the surface of the skeleton body by material curing.

3. The composite material conductive cooling frame according to claim 2, characterized in that, Metal cooling channels are also formed along the radial direction of the skeleton body; The composite material conductive cooling frame also includes: The metal cooling plate is tightly fitted to the inner wall of the metal cooling channel; The cold head of the external cryogenic refrigerator is directly thermally connected to the metal cold-conducting plate through a cryogenic connector, which introduces the cold energy into the interior of the composite material conductive cooling frame; the heat generated by the excitation coil is transferred to the inner wall of the frame and the metal cold-conducting plate through the G10 wire groove, and is discharged through the metal cold-conducting plate.

4. The composite material conductive cooling frame according to claim 3, characterized in that, The skeleton groove, the metal cooling plate, and the skeleton body are integrated into a non-removable whole structure through integral casting.

5. The composite material conductive cooling frame according to claim 3 or 4, characterized in that, The metal cold-conducting plates are arranged in segments along the arc-shaped skeleton body, and the metal cold-conducting plates are made of materials with high thermal conductivity.

6. The composite material conductive cooling frame according to claim 3, characterized in that, The skeleton groove is formed by directly machining the surface of the skeleton body to form a groove that conforms to the winding path of the excitation coil.

7. The composite material conductive cooling frame according to claim 6, characterized in that, A metal channel is formed along the radial direction of the skeleton body. The wall of the skeleton groove and the inner wall of the skeleton are in close contact with the metal channel. The heat generated by the excitation coil is directly transferred to the metal channel through the wall of the skeleton groove.

8. The composite material conductive cooling frame according to claim 3 or 7, characterized in that, Also includes: A conductive cooling structure, nested or padded between multiple excitation coils, is used to form a secondary heat transport channel in the axial direction of the skeleton body. The conductive cooling structure and the metal cooling channel or metal channel constitute a multi-level, three-dimensional cooling network.

9. The composite material conductive cooling frame according to claim 8, characterized in that, The conductive cooling structure includes a cooling ring or a cooling strip.

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