CN210805245U

CN210805245U - Gas target neutralizer with triangular prism reflective array

Info

Publication number: CN210805245U
Application number: CN201920992681.2U
Authority: CN
Inventors: 杨宪福; 魏会领; 曹建勇
Original assignee: Southwestern Institute of Physics
Current assignee: Southwestern Institute of Physics
Priority date: 2019-06-28
Filing date: 2019-06-28
Publication date: 2020-06-19
Anticipated expiration: 2029-06-28

Abstract

The utility model belongs to the magnetic confinement fusion technology, in particular to a gas target neutralizer with a triangular prism reflective array. The device comprises a neutralization pipeline with a rectangular section, a triangular prism reflection array arranged in the neutralization pipeline and a pure iron shielding case, wherein a circle of cooling water pipe is surrounded by a triangular prism reflection frame; and an air supply structure is arranged at the bottom of the neutralization pipeline and used for supplying neutralized gas into the neutralization pipeline. The triangular prism reflection frame is designed, gas molecules can be reflected, according to the molecular flow characteristics, gas only collides with the wall of the device, the emission angle after collision is irrelevant to incidence, and the emission angle meets the cosine theorem, so that the reflection frame enables the molecules to stay in the neutralizer as much as possible after collision, and the effect of increasing the gas density is achieved.

Description

Gas target neutralizer with triangular prism reflective array

Technical Field

The utility model belongs to the magnetic confinement fusion technique, concretely relates to gas target neutralizers structure.

Background

Neutral beam injection heating is an effective auxiliary heating mode in a controlled nuclear fusion experiment, gas is ionized in a discharge chamber to form plasma, then the plasma is led out by a leading-out-accelerating system to form ion beam current, the ion beam current is converted into neutral particle beam current after collision reaction of a neutralizer and a gas target, and the neutral particle beam current is injected into Tokamak central plasma to play a heating role.

The neutral beam injector is a differential pumping system, the non-ionized gas in the discharge chamber flows downstream to the neutralizer to form an initial gas target, when the ion beam passes through the neutralizer, the ion beam and the gas target collide and react, electrons are captured or stripped and converted into neutral particles, but not all the ions are converted into the neutral particles, ion beam currents with different energies all have the maximum neutralization efficiency in the gas target, and the achievement of the maximum neutralization efficiency of the ion beam is an effective way for improving the injection power of the neutral beam.

When the initial gas target thickness is insufficient, the neutralization efficiency of the ion beam does not reach the maximum neutralization efficiency, and at this time, supplementary feed gas needs to be added at a proper position of the neutralizer to increase the gas target thickness, especially for the negative ion beam with higher energy, the added supplementary feed gas may be several times of the amount of the downstream gas, the gas enters a vacuum chamber as the gas load of a neutral beam injector, the load and the reionization loss probability of a main pump are increased, and even Tokamak plasma is damaged, so that the optimal neutralization efficiency is usually 95% of the maximum neutralization efficiency of the ion beam in engineering, and the required gas target thickness is the optimal gas target thickness. The optimal gas target thickness in the neutralizer is determined according to the energy and the positive and negative polarities of the ion beam, the uniflow gas flow rate without ionization is determined by the ion source discharge parameters, and the gas target thickness reaches the optimal gas target thickness by supplementing gas supply in the insufficient part.

The gas target neutralizer is the preferred neutralizer of most neutral beam injectors due to the advantages of simple structure, low operation cost and the like, and the gas target neutralizer is also selected by the neutral beam injector of a fusion device of a certain model. In a certain type of fusion device, the optimal gas target thickness needs to be realized, meanwhile, the gas load of a beam line is reduced, and the influence of a Tokamak stray field on the ion beam current transmission track of the neutralizer is shielded, so that a novel adaptive gas target neutralizer needs to be designed.

Disclosure of Invention

The utility model aims at providing a gas target neutralizers with triangular prism reflect array can reach the gaseous target of best thickness, reduces bunch gas load simultaneously.

The technical scheme of the utility model as follows:

a gas target neutralizer with a triangular prism reflection array comprises a neutralization pipeline with a rectangular section, a triangular prism reflection array which is arranged in the neutralization pipeline and consists of a plurality of triangular prism reflection frames, a pure iron shielding cover arranged outside the neutralization pipeline, and a cooling water pipe which surrounds a circle along each triangular prism reflection frame; the water inlet and the water outlet of the cooling water pipe all penetrate through the neutralization pipeline and the pure iron shielding cover; the triangular prism reflecting frames are arranged in parallel and at equal intervals; and the bottom of the neutralization pipeline is provided with an air supply structure for supplying neutralized gas into the neutralization pipeline.

The triangular prism reflection frame is formed by welding four sections of triangular prisms with right-angled triangle sections.

The right triangle is a 60-degree right triangle, the side face of the right-angle short side of the cross section of the triangular prism reflection frame is in contact with the side wall of the neutralization pipeline, the side face of the right-angle short side of the cross section of the triangular prism reflection frame is perpendicular to the direction of the ion beam current, and the direction of the outer normal of the side face of the bevel edge of the cross section of the triangular prism is deviated to the inlet direction of the.

The air supply structure comprises a mounting sleeve which penetrates through the lower part of the pure iron shielding cover and is welded with the neutralization pipeline and a coaxial air supply pipe arranged in the mounting sleeve, wherein the lower end of the mounting sleeve is a screw cap, and the air supply pipe penetrates through the pure iron shielding cover and the neutralization pipeline and extends into an ion beam flowing space formed by surrounding the neutralization pipeline.

The gas delivery end of the gas delivery pipe is provided with a deflection section, and the deflection direction faces to the ion beam flow inlet.

The length-diameter ratio of the deflection section is 1-5.

The deflection angle of the deflection section is 140-160 degrees.

The diameter of the cooling water pipe is 6-8 mm.

The nut and the mounting sleeve are connected in a sealing mode through a sealing ring.

The interval between adjacent triangular prism reflection frames in the triangular prism reflection array is 100-120 mm.

The utility model discloses an effect as follows:

in order to realize the optimal target thickness and minimize the gas load, a triangular prism reflection frame is designed, which can reflect gas molecules, according to the molecular flow characteristics, the gas only collides with the wall of the device, the emission angle after collision is irrelevant to incidence, and the emission angle meets the cosine theorem, so that the reflection frame enables the molecules to stay in the neutralizer as much as possible after collision, and the effect of increasing the gas density is achieved.

In order to ensure the size of an ion beam channel, the height of the reflecting frame is fixedly designed, and the angle of the reflecting surface is adjusted to form an angle of 60 degrees with the beam direction, so that the thickness of a gas target formed by downstream gas reaches the maximum value.

A reflection array is formed by triangular prism reflection frames with the same structure, and the distance between every two reflection frames is designed to increase the reflection probability.

If the initial gas target thickness formed by the forward flow gas is insufficient, a supplemental gas supply needs to be added to increase the gas target thickness. The cross section of the prism is designed into a right-angled triangle with an angle of 60 degrees, the side face where the right-angled short side of the cross section is located is in contact with the side wall of the neutralization pipeline and is perpendicular to the beam direction, and the direction of the outer normal of the side face where the oblique side of the cross section is located is deviated to the inlet direction of the neutralization pipeline. Four triangular prisms with the same structure form a reflection frame in a surrounding mode, and the side faces where the short right-angle sides are located are aligned with the side walls of the neutralization pipelines respectively. An array formed by a plurality of triangular prism reflecting frames is arranged to increase the reflecting probability.

The upper end of the gas supply pipe is provided with a deflection section, the length-diameter ratio of the deflection section is limited, the linear density of the gas obtained by the same neutralized gas supply flow is the largest, and the neutralized gas supply increases the thickness of the gas target.

The ion beam in the neutralizer is a charged ion stream, the transmission track of the ion beam is deflected by a weak electromagnetic field and then is hit on other parts, the distance of the Tokamak stray field in the neutralizer is still hundreds of gausses, therefore, a shield cover made of pure iron is arranged outside the whole neutralizer, and the length of the shield cover is larger than that of the neutralizer by considering the edge effect. The shielding cover effectively shields the influence of the Tokamak stray field on the transmission track of the ion beam of the neutralizer, and the extension section of the shielding cover avoids the edge effect of the stray field.

Due to space charge effect, particularly the current density of positive ion beam current is large, beam current has a certain divergence angle, ions at the edges of the beam current mainly hit the triangular prism reflecting frame, and part of the ions hit the wall of the device, so that a cooling water pipe with a certain diameter range is arranged on each triangular prism reflecting frame.

Drawings

FIG. 1 is a schematic diagram of a gas target neutralizer with a triangular prism reflector array;

FIG. 2 is a schematic diagram of a triangular prism reflective array;

FIG. 3 is a schematic vertical cross-section of a neutralizer;

FIG. 4 is a schematic view of a triangular prism reflection frame and a cooling water pipe;

FIG. 5 is a schematic view of the position of the gas supply structure and the ion beam current direction;

FIG. 6 is a schematic view of a gas delivery structure;

FIG. 7 is a schematic view of the deflection section of the plenum;

in the figure: 1. a triangular prism reflection frame; 2. a pure iron shield; 3. a neutralization pipeline; 4. an air supply structure; 5. a main water inlet pipe; 6. a primary water return pipe; 7. a cooling water pipe; 8. an air supply pipe; 9. a deflection section; 10. a nut; 11. installing a sleeve; 12. and (5) sealing rings.

Detailed Description

The present invention will be further explained with reference to the drawings and the detailed description.

The neutralizer structure as shown in fig. 1 and 2 comprises a triangular prism reflection array formed by a plurality of triangular prism reflection frames 1, wherein the triangular prism reflection frames 1 are arranged in parallel and at equal intervals, a circle of cooling water pipe 7 surrounds each triangular prism reflection frame 1, after the array is formed, a water inlet of each cooling water pipe 7 faces to the same direction, and a water outlet faces to the same direction. The outside neutralization pipeline 3 that is of triangular prism reflect array, the outside pure iron shield cover 2 that is of neutralization pipeline 3, the water inlet and the delivery port of above-mentioned condenser tube 7 all pass neutralization pipeline 3 and pure iron shield cover 2, later all water inlets and the main inlet tube 5 intercommunication of installing in pure iron shield cover 2 outsides, all delivery ports and the main wet return 6 intercommunication of installing in pure iron shield cover 2 outsides, main inlet tube 5 and the parallel mount of main wet return 6.

The whole triangular prism reflection array is positioned in a neutralization pipeline 3 with a rectangular section, and the neutralization pipeline 3 is formed by connecting an upper part and a lower part through screws, so that the disassembly is convenient. The triangular prism reflection frame 1 is fixed in the neutralization pipeline 3 by adopting a spot welding mode, and the rear surface of the triangular prism reflection frame 1 positioned at the tail end is aligned with the tail end of the neutralization pipeline 3. The space surrounded by the neutralizing duct 3 is a space in which the ion beam flows.

The pure iron shielding case 2 is wrapped outside the neutralization pipeline 3, and the pure iron shielding case 1 can be manufactured into an upper part and a lower part which are connected by screws, so that the assembly and disassembly are convenient.

And a supplementary air supply mechanism 4 is arranged at the bottom of the neutralization pipeline 3 and the pure iron shielding case 2.

As shown in fig. 3, one end of the neutralization pipe 3 is provided with a flange structure, and the other end serves as an inlet and an outlet. In the length direction, the pure iron shielding case 2 exceeds the outlet end of the neutralization pipeline 3, the exceeding value is 90-120 mm, and the exceeding value is preferably 100mm, so that the influence of a Tokamak stray field on a charged ion transmission track is shielded.

As shown in fig. 4 and 5, the triangular prism reflection frame 1 is formed by welding four triangular prisms having a right-angled triangle cross section. The cooling water pipe 7 is installed on the triangular prism reflection frame 1.

The cross section of the triangular prism is designed into a right-angled triangle with an angle of 60 degrees, the side face where the short side of the right angle of the cross section is located is in contact with the side wall of the neutralization pipeline, the side face is perpendicular to the beam direction, and the outer normal direction of the side face where the oblique side of the cross section is located is deviated to the inlet direction of the neutralization pipeline.

As shown in fig. 6, the gas supply structure 4 includes a mounting sleeve 11 passing through the lower part of the pure iron shielding case 2 and welded to the neutralization pipe 3, and a coaxial gas supply pipe 8 mounted in the mounting sleeve 11, wherein the gas supply pipe 8 passes through the pure iron shielding case 2 and the neutralization pipe 3 and extends into an ion beam flowing space surrounded by the neutralization pipe 3. The size of the penetration of the air feed pipe 8 is adjusted by the screw connection of the screw cap 10 and the mounting sleeve 11, and sealing and fixing in position are achieved by the sealing ring 12.

As shown in FIGS. 6 and 7, the gas supply end of the gas supply pipe 8 is provided with a deflection section 9 with a deflection angle of 150 degrees, the deflection direction is towards the ion beam flowing inlet, so that the thickness of the gas target obtained by the neutralization gas supply is further increased, and the length-diameter ratio of the deflection section 9 is 1-5. The deflection angle is defined as the angle (obtuse angle) between the axial direction of the deflection section and the ion beam current direction.

When the initial gas target thickness formed by the ion source co-current gas is insufficient, a neutralization gas feed needs to be added to increase the gas target thickness. The spatial angle of gas incidence also satisfies the cosine scattering theorem, giving the incident gas an initial angle, and the molecules move towards the inlet when entering the neutralizer. An inclined feed pipe, i.e. a deflection section 9, is therefore designed, with the axial direction of the feed being offset towards the inlet of the neutralizer. Calculated by the Monte Carlo method, when the deflection angle is 150 degrees (0 degrees along the beam direction), the linear density of the gas obtained by the same neutralized gas supply flow is the largest.

The diameter of the cooling water pipe 7 is 6-8 mm, and preferably 7 mm.

The interval of the triangular prism reflection frame 1 is 100-120 mm, preferably 110 mm.

Claims

1. A gas target neutralizer having a triangular prism reflectarray, comprising: the device comprises a neutralization pipeline (3) with a rectangular section, a triangular prism reflection array which is arranged in the neutralization pipeline (3) and consists of a plurality of triangular prism reflection frames (1), a pure iron shielding case (2) which is arranged outside the neutralization pipeline (3), and a cooling water pipe (7) which surrounds a circle along each triangular prism reflection frame (1); the water inlet and the water outlet of the cooling water pipe (7) completely penetrate through the neutralization pipeline (3) and the pure iron shielding case (2); the triangular prism reflection frames (1) are arranged in parallel at equal intervals; and an air feeding structure (4) is arranged at the bottom of the neutralization pipeline (3) and used for feeding neutralized gas into the neutralization pipeline (3).

2. A gas target neutralizer having a triangular prism reflector array in accordance with claim 1, wherein: the triangular prism reflection frame (1) is formed by welding four triangular prisms with right-angled triangle sections.

3. A gas target neutralizer having a triangular prism reflector array in accordance with claim 2, wherein: the right triangle is a 60-degree right triangle, the side face where the cross section right-angle short side is located in the triangular prism reflection frame (1) is in contact with the side wall of the neutralization pipeline (3), the side face is perpendicular to the direction of ion beam current, and the direction of an outer normal line of the side face where the cross section bevel edge is located is deviated to the inlet direction of the neutralization pipeline (3).

4. A gas target neutralizer having a triangular prism reflector array in accordance with claim 1, wherein: the gas supply structure (4) comprises a mounting sleeve (11) which penetrates through the lower part of the pure iron shielding cover (2) and is welded with the neutralization pipeline (3) and a coaxial gas supply pipe (8) arranged in the mounting sleeve (11), the lower end of the mounting sleeve (11) is provided with a screw cap (10), and the gas supply pipe (8) penetrates through the pure iron shielding cover (2) and the neutralization pipeline (3) and extends into an ion beam flowing space formed by surrounding of the neutralization pipeline (3).

5. A gas target neutralizer having a triangular prism reflector array in accordance with claim 4, wherein: the gas delivery end of the gas delivery pipe (8) is provided with a deflection section (9), and the deflection direction faces to the ion beam flow inlet.

6. A gas target neutralizer having a triangular prism reflector array in accordance with claim 5, wherein: the length-diameter ratio of the deflection section (9) is 1-5.

7. A gas target neutralizer having a triangular prism reflector array in accordance with claim 5, wherein: the deflection angle of the deflection section (9) is 140-160 degrees.

8. A gas target neutralizer having a triangular prism reflector array in accordance with claim 5, wherein: the diameter of the cooling water pipe (7) is 6-8 mm.

9. A gas target neutralizer having a triangular prism reflector array in accordance with claim 5, wherein: the screw cap (10) is connected with the mounting sleeve (11) in a sealing mode through a sealing ring (12).

10. A gas target neutralizer having a triangular prism reflector array in accordance with claim 2, wherein: the interval between adjacent triangular prism reflection frames (1) in the triangular prism reflection array is 100-120 mm.