A nuclear fusion superconducting magnet autoclave VPI closed-loop heating system and method

Abstract

The present invention provides a nuclear fusion superconducting magnet autoclave VPI closed-loop heating system and method, which relates to the field of nuclear fusion magnet insulation manufacturing. A large-section spiral tube coil is installed in a VPI mold and placed in an autoclave, connected to an internal heating system through a connector terminal, and non-inductive heating inside the coil is achieved by respectively passing reverse current to the coil connector terminal and the winding middle connector; the autoclave is respectively connected to a vacuum pumping system, a pressing system, a heating system and a glue injection system; the temperature acquisition system is respectively connected to the internal heating system, the autoclave and the VPI mold-related thermometer; the large-section spiral tube coil is used as a heating wire to achieve internal heating of the winding, and as a thermometer to achieve the acquisition of the internal temperature of the winding, and the "temperature-resistance" curve of the coil conductor is used as a temperature control benchmark for external heating to achieve precise control of the autoclave temperature. The present invention realizes non-inductive heating inside the winding, precise temperature measurement and external coordinated temperature control.

Description

Technical Field

[0001] The invention relates to the field of nuclear fusion toroidal field magnet insulation manufacturing, and in particular to a nuclear fusion superconducting magnet autoclave VPI closed-loop heating system and method. Background Art

[0002] The Tokamak device is recognized as an ideal device for humans to achieve magnetic confinement nuclear fusion energy, and the magnet system is the core component of the Tokamak device. Fusion energy is proportional to the fourth power of the magnetic field and the third power of the radius. The magnetic field strength determines the most critical factor for the fusion device to produce fusion energy. Therefore, the construction scale of the Tokamak device continues to expand. The nuclear fusion superconducting magnet system usually includes 16 toroidal field (TF) magnet systems, 6 / 7 poloidal field (PF) magnet systems, central spiral tube (CS) magnet systems and several correction field (CC) magnet systems. Among them, compared with the TF coil, the outer dimensions of the PF2-5 coil, the dimensions of the PF1, PF6 / 7 and large-section spiral tube superconducting magnets are relatively small, usually referred to as large-section spiral tube superconducting coils, and their coil winding and VPI (Vacuum Pressure Impregnation) manufacturing are relatively difficult.

[0003] For nuclear fusion large-section spiral tube superconducting magnets and poloidal field PF1, PF6 / 7 coils, the cross-sectional dimensions are large, the coil height is relatively high, and the coil profile is relatively small. The vacuum pressure impregnation process usually uses a VPI mold to control the external dimensions and seal the impregnation cavity, and then places it in an autoclave to complete heating and vacuum degassing before vacuum pressure impregnation. The autoclave is used to heat and solidify the VPI mold and winding according to the corresponding temperature curve to achieve coil solidification.

[0004] The internal conductors of the large-section, small-profile spiral tube coil windings are filled with inter-turn insulation, inter-layer insulation, inter-cake insulation and ground insulation composed of glass fiber reinforced materials. The above insulation materials have good thermal insulation properties. Traditional autoclaves have heating, temperature measurement, heat preservation and pressure-pressing functions. During the heating process of the VPI mold through the autoclave, the temperature of the outer winding in contact with the VPI mold is quite different from the temperature of the center of the winding. The internal degassing effect is poor during heating and degassing. During the heating and curing process, the resin gel and curing shrinkage are not synchronized, which will cause shrinkage gaps inside. The cooling process will cause cracks between the center area and the outside of the winding cross section due to the temperature difference. Therefore, it is urgent to solve the problem of coil cross-section temperature uniformity and internal temperature measurement during the VPI process. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a nuclear fusion superconducting magnet autoclave VPI closed-loop heating system and method, which realizes non-inductive heating inside the winding, precise internal temperature measurement, and external coordinated temperature control points. It has the advantages of simple method, precise temperature control, and saving manufacturing time.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] A nuclear fusion superconducting magnet autoclave VPI closed-loop heating system, comprising an autoclave, a vacuum system, a pressing system, a glue injection system, a VPI mold, an external heating system and an internal heating system; the autoclave is connected to the vacuum system, the pressing system, the external heating system and the glue injection system respectively, an inner cavity is formed between the inner and outer walls of the autoclave, and an external heating system is arranged in the inner cavity; the external heating system is a large-section spiral tube coil, which provides an auxiliary heating method for heat convection; the internal heating system is connected to the large-section spiral tube coil through an internal joint terminal; the vacuum system is connected to the internal space of the autoclave; the glue injection The system is connected to the inner cavity of the autoclave; the pressurizing system injects gas after the large-section spiral tube coil is impregnated with glue; the large-section spiral tube coil is installed in a VPI mold and placed in the autoclave, and is connected to the internal heating system through internal joint terminals; the temperature acquisition system is respectively connected to the thermometers of the internal heating system, the autoclave and the VPI mold, and the resistance value of the pre-tested conductor under different temperature conditions is used as a benchmark to calculate the resistance of the large-section superconducting spiral tube coil at different temperatures, obtain the "temperature-resistance" curve of the large-section superconducting spiral tube coil, and realize the test of the internal temperature of the large-section superconducting spiral tube coil.

[0008] Furthermore, the large-section spiral tube coil acts as a heating wire, which is heated internally by energizing it, and also as a thermometer. During the heating process, the resistance of the large-section spiral tube coil is collected through an independent circuit, and the internal temperature of the coil is calculated through the "temperature-resistance" curve; at the same time, the calculated internal temperature of the coil is used as the temperature control benchmark for external heating to achieve precise control of the autoclave temperature.

[0009] Furthermore, the internal heating system is located outside the autoclave.

[0010] Further, the vacuum system is located outside the autoclave;

[0011] Furthermore, the glue injection system is located at the outer bottom of the autoclave.

[0012] Furthermore, the wound large-section spiral tube coil is installed in a VPI mold and after size control, insulation isolation and vacuum sealing are completed, it is placed in an autoclave for vacuum pressure impregnation.

[0013] The present invention also provides a VPI closed-loop heating method for a nuclear fusion superconducting magnet autoclave, comprising: dividing the large-section spiral tube coil into an upper half winding and a lower half winding; connecting the two ends of the upper half winding and the lower half winding to their respective internal joint terminals, and connecting the upper half winding and the lower half winding through a middle internal joint terminal, the internal joint terminal being an integrated middle structure terminal, and performing inductive coupling by respectively passing positive and reverse currents through the upper half winding and the lower half winding to the internal heating system, thereby realizing non-inductive heating of the coil.

[0014] Furthermore, the internal heating system is composed of two sets of heating power supplies, the positive pole of one set of heating power supplies is connected to the internal connector terminal of the upper half winding, and the negative pole is connected to the middle connector terminal, and a forward current flows; the negative pole of the other set of heating power supplies is connected to the internal connector terminal of the lower half winding, and the negative pole is connected to the middle connector terminal, and a reverse current flows.

[0015] Furthermore, the heating power supply adopts a safety voltage not higher than 36V and a high current DC power supply of 800-1200A.

[0016] In the present invention, the wound large-section spiral tube coil is installed in a VPI mold and after the size control, insulation isolation and vacuum sealing are completed, it is placed in an autoclave for vacuum pressure impregnation. The large-section spiral tube coil is connected to the internal heating system through the internal joint terminal. The internal joint of the large-section spiral tube coil is connected with the internal joint terminal by jumper wire. The heating power supply of the internal heating system adopts a low-voltage, high-current DC power supply. The inductive coupling is performed by passing a forward current through half of the winding of the large-section spiral tube coil and a reverse current through the other half, thereby realizing non-inductive heating of the coil. The conductor of the large-section spiral tube coil can be used as a thermometer. By pre-testing the resistance value of the conductor under different temperature conditions and measuring the resistance value of the large-section spiral tube coil, the internal temperature of the coil can be tested. In terms of control, the external heating system heats the autoclave according to the established heating temperature curve, and at the same time, the tested internal temperature of the large-section spiral tube coil is used as the temperature control signal of the external heating system. By continuously adjusting the current of the external heating power supply, the real-time and accurate closed-loop control of the temperature of the external heating system of the autoclave is realized, thereby forming a closed-loop control system for external heating of the autoclave and internal heating of the large-section spiral tube coil, thereby realizing precise control of the internal and external heating temperature difference better than 5°C.

[0017] Beneficial effects:

[0018] The present invention overcomes the coil manufacturing quality risk caused by the mismatch between the external mold temperature, the external temperature of the winding and the center temperature of the winding during the VPI manufacturing process of large-section spiral tube coils using traditional autoclaves. For the first time, a collaborative, closed-loop automatic control system of the coil's internal non-inductive heating and temperature measurement system and the VPI mold temperature and autoclave temperature is adopted to achieve precise control of the heating temperature during the VPI process of large-section fusion reactor spiral tube magnets. The present invention achieves non-inductive heating of the winding inside, precise internal temperature measurement, and external collaborative temperature control, and has the advantages of simple method, precise temperature control, and saving manufacturing time. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of a nuclear fusion superconducting magnet autoclave VPI closed-loop heating system of the present invention;

[0020] Figure 2 It is a structural schematic diagram of the current flow direction of the large-section spiral tube coil of the present invention;

[0021] Figure 3 Another structural schematic diagram of the current flow direction of the large-cross-section spiral tube coil of the present invention.

[0022] Among them, the figure markings are: 1-internal heating system; 2-autoclave; 3-temperature acquisition system; 4-external heating system; 5-glue injection system; 6-vacuum system; 7-large-section spiral tube coil; 8-VPI mold; 9-internal connector terminal; 10-heating power supply; 11-upper half winding; 12-middle connector terminal; 13-pressing system; 14-lower half winding; 15-glue bubbling structure. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other. The present invention is further described below in conjunction with specific embodiments.

[0024] like Figure 1 As shown, the present invention provides a nuclear fusion superconducting magnet autoclave VPI closed-loop heating system, including an autoclave 2, a vacuum pumping system 6, a pressing system 13, a glue injection system 5, a VPI mold 8, an external heating system 4, a temperature acquisition system 3 and an internal heating system 1.

[0025] The autoclave 2 is respectively connected to the vacuum system 6, the pressing system 13, the external heating system 4 and the glue injection system 5. An inner cavity is formed between the inner and outer walls of the autoclave 2, and the external heating system 4 is arranged in the inner cavity. The external heating system 4 provides an auxiliary heating method of heat convection for the large-section spiral tube coil 7 arranged in the autoclave 2.

[0026] The internal heating system 1 is located outside the autoclave 2 and is connected to the large-section spiral tube coil 7 via an internal joint terminal. The internal heating system 1 provides active heating by heat conduction for the large-section spiral tube coil 7 through electric current.

[0027] The vacuum system 6 is located outside the autoclave 2 and is connected to the internal space of the autoclave 2 through a positive pressure resistant metal bellows. The bottom of the VPI mold 8 is connected to the glue injection system 5 through a glue injection hose. A glue emitting structure 15 is provided on the upper part. The glue emitting structure 15 is an open structure. The vacuum inside the autoclave and the glue emitting structure 15 of the VPI mold 8 are at the same atmospheric pressure. After the vacuum system 6 is started, the VPI mold 8 removes the internal air of the large-section spiral tube coil 7 through its glue emitting structure 15 and discharges it out of the autoclave 2.

[0028] The glue injection system 5 is located at the outer bottom of the autoclave 2 and is connected to the VPI mold 8 inside the autoclave 2 through a glue injection hose, and is used for glue injection and dipping of the large-section spiral tube coil 7 inside the VPI mold 8.

[0029] After the VPI glue impregnation of the large-section spiral tube coil 7 is completed, the compression system 13 injects gas into the autoclave, and through the glue emitting structure 15 of the VPI mold 8, the resin of the large-section spiral tube coil 7 after impregnation is reversely compressed, thereby compressing the bubbles that may exist inside the coil and improving the high-pressure resistance of the coil.

[0030] The large-section spiral tube coil 7 is installed in a VPI mold 8 and placed in an autoclave 2 , and is connected to an internal heating system 4 via an internal joint terminal 9 .

[0031] The temperature acquisition system 3 is connected to the thermometers of the internal heating system 4, the autoclave 2 and the VPI mold 8 respectively. The resistance values ​​of the pre-tested conductors under different temperature conditions are used as a reference to calculate the corresponding resistances of the large-section superconducting spiral tube coil at different temperatures, and obtain the "temperature-resistance" curve of the coil. By collecting the resistance data of the large-section spiral tube coil 7 during the heating process, the temperature data of the conductor is calculated to realize the internal temperature test of the coil.

[0032] The large-section spiral tube coil 7 is used as a heating wire, and a low voltage of no more than 36V and a large current of about 800-1200A are passed into the large-section spiral tube coil 7 to heat the inside of the large-section spiral tube coil 7. The resistance data of the large-section spiral tube coil 7 during the heating process is collected, and the temperature data of the conductor is calculated to collect the internal temperature of the winding. The internal temperature is used as a feedback signal for external heating to realize closed-loop control of the autoclave temperature.

[0033] like Figure 2 , Figure 3 As shown, the present invention provides a nuclear fusion superconducting magnet autoclave VPI closed-loop heating method, comprising: dividing the large-section spiral tube coil 7 into an upper half winding 11 and a lower half winding 14; the two ends of the upper half winding 11 and the lower half winding 14 are connected to their respective internal connector terminals 9, and the upper half winding 11 and the lower half winding 14 are connected through the middle internal connector terminal 12, and the internal connector terminal 12 is an integrated intermediate structure terminal, and inductive coupling is performed by passing positive and reverse currents through the upper half winding 11 and the lower half winding 14 respectively, thereby realizing non-inductive heating of the coil.

[0034] The internal heating system 1 is composed of two sets of heating power supplies 10, wherein the positive pole of one set of heating power supplies 10 is connected to the internal connector terminal 9 of the upper half winding 11, and the negative pole is connected to the middle connector terminal 12, so that a forward current flows through it; the negative pole of the other set of heating power supplies 10 is connected to the internal connector terminal 9 of the lower half winding 14, and the negative pole is connected to the middle connector terminal 12, so that a reverse current flows through it; the middle connector terminal 12 bears both the forward current flowing through the upper half winding 11 and the reverse current flowing through the lower half winding 14, and the two windings generate magnetic fields and inductances in different directions, which offset each other to achieve inductive heating of the coil.

[0035] Preferably, the heating power supply 10 adopts a low voltage not exceeding 36V and a high current DC power supply of about 800-1200A.

Claims

1. A nuclear fusion superconducting magnet autoclave VPI closed-loop heating system, characterized in that: It includes an autoclave, a vacuum system, a pressing system, a glue injection system, a VPI mold, a temperature acquisition system, an external heating system and an internal heating system; the autoclave is connected to the vacuum system, the pressing system, the external heating system and the glue injection system respectively, an inner cavity is formed between the inner and outer walls of the autoclave, and an external heating system is arranged in the inner cavity; the external heating system provides an auxiliary heating method of heat convection for the large-section spiral tube coil; the internal heating system is connected to the large-section spiral tube coil through an internal joint terminal; the vacuum system is connected to the internal space of the autoclave; the glue injection system is connected to the inner cavity of the autoclave; The pressure system injects gas after the large-section spiral tube coil is impregnated with glue; the large-section spiral tube coil is installed in the VPI mold and placed in the autoclave, and connected to the internal heating system through the internal joint terminal; the temperature acquisition system is connected to the thermometers of the internal heating system, the autoclave and the VPI mold respectively, and the resistance value of the pre-tested conductor under different temperature conditions is used as a benchmark to calculate the resistance of the large-section superconducting spiral tube coil at different temperatures, obtain the "temperature-resistance" curve of the large-section superconducting spiral tube coil, and realize the test of the internal temperature of the large-section superconducting spiral tube coil; The large-section spiral tube coil is used as a heating wire to achieve internal heating by energizing it, and also as a thermometer. During the heating process, the resistance of the large-section spiral tube coil is collected through an independent circuit, and the internal temperature of the large-section spiral tube coil is calculated through the "temperature-resistance" curve. At the same time, the calculated internal temperature of the large-section spiral tube coil is used as the temperature control benchmark for external heating to achieve precise control of the temperature of the autoclave. The coil uses non-inductive heating inside to achieve precise internal temperature measurement and external coordinated temperature control.

2. A nuclear fusion superconducting magnet autoclave VPI closed-loop heating system according to claim 1, characterized in that: The internal heating system is located outside the autoclave.

3. A nuclear fusion superconducting magnet autoclave VPI closed-loop heating system according to claim 1, characterized in that: The vacuum system is located outside the autoclave.

4. A nuclear fusion superconducting magnet autoclave VPI closed-loop heating system according to claim 1, characterized in that: The glue injection system is located at the bottom of the outer side of the autoclave.

5. A nuclear fusion superconducting magnet autoclave VPI closed-loop heating system according to claim 1, characterized in that: The wound large-section spiral tube coil is installed in the VPI mold and after size control, insulation isolation and vacuum sealing are completed, it is placed in the autoclave for vacuum pressure impregnation.

6. A closed-loop heating method for a nuclear fusion superconducting magnet autoclave VPI closed-loop heating system according to any one of claims 1 to 5, characterized in that: include: The large-section spiral tube coil is divided into an upper winding and a lower winding; the two ends of the upper winding and the lower winding are connected to their respective internal joint terminals, and the upper winding and the lower winding are connected through a middle internal joint terminal, and the internal joint terminal is an integrated middle structure terminal. The upper winding and the lower winding are connected to an internal heating system, and inductive coupling is performed by respectively passing positive and reverse currents into the internal heating system, thereby realizing non-inductive heating of the large-section spiral tube coil.

7. The closed-loop heating method according to claim 6, characterized in that: The internal heating system consists of two sets of heating power supplies, one set of heating power supplies has a positive pole connected to the internal connector terminal of the upper half winding, and a negative pole connected to the middle connector terminal, and a forward current flows through it; the other set of heating power supplies has a positive pole connected to the internal connector terminal of the lower half winding, and a negative pole connected to the middle connector terminal, and a reverse current flows through it.

8. The closed-loop heating method according to claim 7, characterized in that: The heating power supply is a direct current power supply with a safety voltage not higher than 36V and a large current of 800-1200A.

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