CN109273188B

CN109273188B - Annular magnet based on ReBCO superconducting ring piece

Info

Publication number: CN109273188B
Application number: CN201811147579.9A
Authority: CN
Inventors: 袁茜; 王银顺; 胡一丹; 刘明闯; 皮伟; 李继春; 夏芳敏
Original assignee: Futong Group Tianjin Superconductor Technologies And Application Co ltd; North China Electric Power University
Current assignee: Futong Group Tianjin Superconductor Technologies And Application Co ltd; North China Electric Power University
Priority date: 2018-09-29
Filing date: 2018-09-29
Publication date: 2021-01-01
Anticipated expiration: 2038-09-29
Also published as: CN109273188A

Abstract

The invention discloses a circumferential magnet based on ReBCO superconducting ring sheets, belonging to the technical field of superconducting magnet application. The annular magnet is formed by uniformly distributing and combining a plurality of identical unit annular field magnets in an annular direction, wherein the unit annular field magnets are obtained by alternately stacking and fixing N pieces of ReBCO superconducting annular sheets and N +1 pieces of insulating sheets, and N is a positive integer; the ReBCO superconducting ring sheets are D-shaped ring sheets, and the shape and the size of the N +1 insulating sheets are the same as those of the N ReBCO superconducting ring sheets; the method of adopting the low-temperature Dewar immersion type cooling magnet has the advantages of high magnetic body current carrying capacity, low heat leakage, compact structure, detachability and the like, can generate a magnetic field with stable large space, and is widely applied to the fields of medium-large Tokamak magnets, thermonuclear fusion reactions and the like.

Description

Annular magnet based on ReBCO superconducting ring piece

Technical Field

The invention belongs to the technical field of superconducting magnet application, and particularly relates to a circumferential magnet based on ReBCO superconducting ring sheets.

Background

With the continuous improvement of the performance of the high-temperature superconducting wire, the research and development work of the high-temperature superconducting magnet is also steadily carried out. The high-temperature superconducting ring magnet is a structural form of a high-temperature superconducting magnet, and the most important and most promising application occasions are thermonuclear fusion and Tockmark ring magnets. The annular magnet is formed by uniformly distributing a plurality of identical unit coils along a large ring, and can generate a large-space stable magnetic field.

The low temperature superconducting wire that present tokamak magnet adopted comes the coiling, and operating temperature is very low, and magnet refrigeration power is big, and the magnetic field value that reaches is limited, if replace low temperature superconducting wire with high temperature superconducting wire and come the coiling ring magnet, just can improve the operating temperature of magnet, reduce refrigeration power, and high temperature superconducting material's last critical magnetic field is higher than low temperature material moreover, can improve the magnetic field intensity of ring magnet to new level, also is very good to improving fusion reaction power. However, the high-temperature superconducting wire is used, the joint of the high-temperature superconducting wire is inevitably welded, and a current lead is also required to be connected with a power supply, so that the heat leakage of the magnet is large.

Disclosure of Invention

The invention aims to provide a circumferential magnet based on ReBCO superconducting ring sheets, and the specific technical scheme is as follows:

a circumferential magnet based on ReBCO superconducting ring pieces is formed by uniformly distributing and combining a plurality of same unit circumferential field magnets in the circumferential direction, wherein the unit circumferential field magnets are obtained by alternately stacking and fixing N ReBCO superconducting ring pieces and N +1 insulating pieces, and N is a positive integer;

the ReBCO superconducting ring sheets are D-shaped ring sheets, and the shape and the size of the N +1 insulating sheets are the same as those of the N ReBCO superconducting D-shaped ring sheets.

Wherein, 1 corner or 2 corners of D shape inner ring of D shape ring piece cut circular locating hole.

Wherein, the D-shaped ring plates of 2 corners of the D-shaped inner ring cutting the round positioning holes are axisymmetric.

The ReBCO superconducting ring sheet consists of a substrate, a buffer layer, a ReBCO film and a protective layer which are sequentially arranged from bottom to top; the substrate material is Ni, NiW, Hastelloy or stainless steel; the buffer layer is made of insulating metal oxide; the protective layer is a silver film protective layer or a copper film protective layer. Wherein, the buffer layer is deposited by using an ion beam assisted deposition technology or an inclined substrate deposition technology, and the ReBCO film is deposited by using a metal organic chemical vapor deposition method, a pulse laser deposition method or a sputtering method.

Wherein, the stacking direction of the N pieces of ReBCO superconducting ring pieces is consistent.

Wherein, the insulating sheet is an organic insulating sheet, kraft paper or an epoxy sheet.

The fixing of the annular magnet comprises the fixing of a single unit annular field magnet and the fixing of the whole annular magnet, the annular steel armor support can be used for fixing in an annular cavity inside the unit annular field magnet, then the single unit annular field magnet is fixed by using a flange plate, a nut, a bolt and a steel armor, and the whole annular magnet is fixed by using a support cylinder and the steel armor support by using the fixing method of the existing Turke Mark device; the fixing material is preferably stainless steel, epoxy glass reinforced plastic or epoxy resin.

The annular magnet adopts the internal excitation of a magnetic flux pump and adopts a low-temperature Dewar immersion type cooling magnet mode to realize the closed-loop operation of the annular magnet.

The magnetic flux pump comprises a pulse power supply and a solenoid coil; the method specifically comprises the following steps: the solenoid coil passes through the circular positioning hole of the annular magnet to excite the annular magnet, the pulse power supply provides alternating current, the magnetic field of the annular magnet is continuously increased to a desired value through periodic excitation, the current of the annular magnet is kept constant, and a stable magnetic field is maintained.

The invention has the beneficial effects that: the ReBCO superconducting ring sheet is designed into a D-shaped ring sheet, so that the application range of the ReBCO superconductor to a strong magnetic field and thermonuclear fusion is expanded; the annular superconducting magnet obtained by annularly stacking the insulating sheets can output a large-space stable magnetic field, and can realize closed-loop operation without welding among all ReBCO superconducting annular sheets inside and large power supply and current lead wires; the magnetic field in a stable large space can be generated, the configuration and the magnetic field intensity of the magnetic field required by plasma confinement are met, and the magnetic field can be widely applied to the fields of medium-large Tokamak magnets, thermonuclear fusion reactions and the like.

Drawings

FIG. 1 is a schematic structural diagram of a ReBCO superconducting sheet;

description of reference numerals: 1-ReBCO superconducting foil; 101-a substrate; 102-a buffer layer; 103-ReBCO film; 104-a protective layer;

FIG. 2 is a schematic structural diagram of a ReBCO superconducting ring sheet;

FIG. 3 is a schematic view of an insulating sheet structure;

FIG. 4 is a schematic view showing the structure of a ring-shaped magnet according to example 4;

FIG. 5 is a schematic view showing the structure of the ring-shaped magnet according to example 5;

description of reference numerals: 2-the I ReBCO superconducting ring sheet; 3-II ReBCO superconducting ring sheets; 4-the I insulating sheet; 5-II insulating sheet; 6-the first unit annular field magnet; 7-the ith annular magnet; 8-the second unit annular field magnet; 9-IIth annular magnet; 10-a hollow solenoid coil; 11-pulsed power supply.

Detailed Description

The invention provides a circumferential magnet based on ReBCO superconducting ring sheets, which is further described by combining the embodiment and the attached drawings.

Example 1

A ReBCO superconducting thin sheet as shown in the attached figure 1 is prepared by the following specific processes:

(1) manufacturing a sheet-shaped substrate 101 by using a substrate material which is the same as that of the second-generation high-temperature superconducting coating, wherein the substrate material is Ni, NiW, Hastelloy or stainless steel;

(2) depositing a buffer layer 102 on a substrate 101 by adopting a second-generation high-temperature superconducting buffer layer preparation process, wherein the buffer layer is an insulating metal oxide;

(3) plating a ReBCO film 103 on the buffer layer 102 by adopting a second-generation high-temperature superconducting film coating technology;

(4) and plating a protective layer 104 on the ReBCO film 103, wherein the protective layer 104 is a silver film protective layer or a copper film protective layer, and thus the ReBCO superconducting sheet 1 is obtained.

Wherein the second generation high temperature superconducting buffer layer preparation process is Ion Beam Assisted Deposition (IBAD) or Inclined Substrate Deposition (ISD); the second generation high temperature superconducting thin film coating technology is Metal Organic Chemical Vapor Deposition (MOCVD), Pulsed Laser Deposition (PLD) or sputtering.

Example 2

The preparation method of the ReBCO superconducting ring sheet shown in the figure 2 comprises the following specific steps:

the specific preparation process of the I ReBCO superconducting ring sheet 2 with positioning circular holes cut at the corners of the D-shaped inner ring 1 shown in the figure 2-a is as follows:

a D-shaped ring piece is cut from the ReBCO superconducting thin sheet obtained in the example 1, and the radius of the inner ring is r₁The outer ring radius is r₂Width of the ring being w₁(ii) a Cutting a radius r at 1 joint of a straight line of the D-shaped inner ring and a circular arc, namely 1 inner ring corner₃The circular positioning hole 201 is used to obtain the first ReBCO superconducting ring sheet 2 shown in fig. 2-a.

The specific preparation process of the II ReBCO superconducting ring sheet 3 with positioning round holes cut at the corners of the D-shaped inner ring 2 shown in the figure 2-b is as follows:

a D-shaped ring piece is cut from the ReBCO superconducting thin sheet obtained in the example 1, and the radius of the inner ring is r₄The outer ring radius is r₅Width of the ring being w₂(ii) a Cutting a radius r at 2 junctions of straight lines of the D-shaped inner ring and circular arcs, namely 2 inner ring corners₆、r₇The second ReBCO superconducting ring piece 3 shown in fig. 2-b is obtained by the

circular positioning holes

301 and 302, wherein the second ReBCO superconducting ring piece 3 is an axisymmetric ring piece.

Example 3

Preparing an insulating sheet as shown in fig. 3: an organic insulating film such as a PPLP insulating material film, kraft paper or epoxy sheet was cut into D-shaped insulating sheets having exactly the same shape and size as those of the ReBCO superconducting ring sheet shown in example 2.

Wherein, fig. 3-a is the I insulating sheet 4 which has the same shape and size with the I ReBCO superconducting ring sheet 2 shown in fig. 2-a; fig. 3-b shows a second insulating sheet 5 having the same shape and size as the second ReBCO superconducting ring sheet 3 shown in fig. 2-b.

Example 4

Preparing a circumferential magnet as shown in fig. 4-a, wherein 4-b is a top view of the circumferential magnet as shown in 4-a; the method specifically comprises the following steps:

(1) firstly, horizontally placing a 1 st insulating sheet I4, stacking a 1 st ReBCO superconducting ring sheet 2 above the 1 st insulating sheet I4, and completely aligning the sheets up and down, left and right during stacking;

(2) sequentially stacking a 2 nd I insulating sheet 4, a 2 nd I ReBCO superconducting ring sheet 2, … …, an Nth I insulating sheet 4, an Nth I ReBCO superconducting ring sheet 2 and an N +1 th I insulating sheet 4 from bottom to top to finish the alternate stacking of the insulating sheets and the ReBCO superconducting ring sheets; fixing the obtained stacked body by using a flange and a bolt to obtain a first unit annular field magnet 6; wherein the stacking directions of the N ReBCO superconducting ring sheets 2 are consistent;

(3) preparing 8 identical unit I annular field magnets 6 according to the steps (1) to (2), and uniformly distributing and fixing the obtained unit annular field magnets 6 in the annular direction to obtain an I annular magnet 7;

(4) adopt the magnetic flux pump technique to realize the closed-loop operation of I ring to magnet 7 through the mode of inside excitation, specifically do: the magnetic flux pump comprises a hollow solenoid coil 10 and a pulse power supply 11, wherein the outer radius of the hollow solenoid coil 10 is smaller than the inner radius of the circular positioning hole 201 of the first annular magnet 7, so that the hollow solenoid coil can be inserted into the circular positioning hole of the annular magnet in an annular spiral manner; the pulse power supply 11 provides alternating current for the hollow solenoid coil, wherein the rising edge time of the output current waveform is far less than the falling edge time; the method is carried out in a periodic excitation mode, wherein each periodic excitation enables the magnetic field of the annular magnet to be increased, when the magnetic field of the annular magnet meets the requirement, the hollow solenoid coil 10 does not need to be removed, the pulse power supply 11 is turned off, the current of the superconducting sheet can be kept constant, a stable magnetic field is maintained, and the influence caused by manual operation is avoided.

Example 5

Stacking a II insulation sheet 5 and a II ReBCO superconducting ring sheet 3 according to the same method as the embodiment 4, fixing to obtain a II unit annular field magnet 8 shown in figure 5-a, and uniformly distributing and fixing 8 identical II unit annular field magnets 8 in an annular direction to obtain a II annular magnet 9; wherein 5-b is a top view of the circumferential magnet shown in 5-a.

The closed-loop operation of the second annular magnet 9 is realized by adopting a magnetic flux pump technology in an internal excitation mode, and specifically, 2 hollow solenoid coils 10 are inserted into

circular positioning holes

301 and 302 of the second annular magnet 9 in an annular spiral mode to realize integral excitation.

Claims

1. A circumferential magnet based on ReBCO superconducting ring pieces is characterized by being formed by uniformly distributing and combining a plurality of identical unit circumferential field magnets in the circumferential direction, wherein the unit circumferential field magnets are obtained by alternately stacking and fixing N ReBCO superconducting ring pieces and N +1 insulating pieces, and N is a positive integer;

the ReBCO superconducting ring sheet is a D-shaped ring sheet, and the shape and the size of the N +1 insulating sheets are the same as those of the N ReBCO superconducting ring sheets;

cutting circular positioning holes at 1 corner or 2 corners of the D-shaped inner ring of the D-shaped ring sheet; the positioning hole and the D-shaped inner ring are provided with 2 intersection points;

the annular magnet is excited by utilizing the inside of a magnetic flux pump, and the magnetic flux pump comprises a pulse power supply and a solenoid coil; the method specifically comprises the following steps: the spiral pipe coil is inserted into the circular positioning hole of the annular magnet in an annular spiral manner to excite the annular magnet, and the pulse power supply provides alternating current.

2. The ReBCO superconducting ring piece-based toroidal magnet of claim 1, wherein the D-shaped inner ring has 2 corners cutting D-shaped ring piece axial symmetry of circular positioning hole.

3. The circumferential magnet based on the ReBCO superconducting ring sheet according to claim 1, wherein the ReBCO superconducting ring sheet is composed of a substrate, a buffer layer, a ReBCO film and a protective layer which are sequentially arranged from bottom to top;

the substrate material is Ni, NiW, Hastelloy or stainless steel;

the buffer layer is made of insulating metal oxide;

the protective layer is a silver film protective layer or a copper film protective layer;

the buffer layer is deposited by using an ion beam assisted deposition technology or an inclined substrate deposition technology, and the ReBCO film is deposited by using a metal organic chemical vapor deposition method, a pulse laser deposition method or a sputtering method.

4. A toroidal magnet as claimed in claim 1, wherein said N ReBCO superconducting ring pieces are stacked in a uniform direction.

5. The toroidal magnet according to claim 1, wherein said insulating sheet is an organic insulating sheet, kraft paper or epoxy sheet.