Aluminum sleeve for double-cone collision ignition low-temperature freezing target and preparation method thereof

Abstract

The present invention provides an aluminum sleeve for double-cone collision ignition low-temperature freezing target and its preparation method, comprising: an intermediate aluminum sleeve, the interior of the intermediate aluminum sleeve is a cavity; a sealing aluminum cover, two sealing aluminum covers are respectively located at the upper and lower ends of the intermediate aluminum sleeve; a sealing membrane, a sealing membrane is provided inside each sealing aluminum cover; the intermediate aluminum sleeve, the sealing aluminum cover and the sealing membrane are sealed and connected to each other, forming a columnar cavity structure model with a cavity inside. The overall structure of the present invention is assembled from discrete units, each part can be independently designed and processed, sealed and connected, and easy to operate, so that the overall structure has a certain degree of flexibility; the present invention is in the shape of an "I" as a whole, and this structure can ensure the temperature control and sealing effect of the core chamber, thereby ensuring the thermal environment of the core target pellet.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear fusion cryogenic freezing targets, and in particular to an aluminum sleeve for a double-cone collision ignition cryogenic freezing target and a preparation method thereof. Background Art

[0002] A cryogenically frozen spherical shell target containing a uniform layer of deuterium-tritium (DT) liquid fuel is an ideal implosion target for integrated fusion (ICF). The key to preparing a cryogenically frozen target is to create a uniform, smooth layer of DT fuel on the target pellet. To achieve implosion, the DT pellet in the cryogenically frozen target must have a root mean square roughness of less than 1 μm and a uniformity of at least 99%. Therefore, after the DT fuel is frozen from gas to solid fuel, the thermal environment must be strictly controlled. Currently, two main cryogenic target models exist: the typical split-column indirect-drive cryogenic target system, which utilizes a cylindrical aluminum sleeve, typically made of high-purity aluminum, as the pellet's temperature control chamber. The other is a multi-beam laser injection spherical cavity cryogenic target system, which utilizes a symmetrical spherical cavity as the temperature control chamber and enables multi-beam laser injection, thus overcoming the limitation of the cylindrical cavity structure, which is limited to only two laser beams.

[0003] Through the search of existing technologies, we found that:

[0004] In "NIF Target Assembly Metrology Methodology and Results," published in Fusion Science and Technology, 2010, 59, E.T. Alger et al. of General Atomics (USA), detailed the structure of the thermomechanical assembly sleeve, which primarily consists of the thermomechanical assembly housing, diagnostic bands, and various windows. The precise dimensions of each component were measured using precision instruments, providing a reference for subsequent design.

[0005] Baibin Jiang et al. from the Laser Fusion Research Center of the China Academy of Engineering Physics published an article titled "Mechanical Design and Analysis of an Indirect-drive Cryogenic" in the Journal of Fusion Energy, 2016, Vol. 3. They improved the cylindrical cavity structure by referencing the NIF ignition target. A protective sleeve was placed around the cylindrical cavity to secure the gas tube, improve sealing, and address other structural issues. A tapered capillary tube was also placed around the gas tube to protect and seal the fuel line and support the internal target sphere. However, a potential challenge lies in the fit between the cavity and the protective sleeve, and between the gas tube and the tapered capillary tube. Effective fit requires precise control of the diameter difference.

[0006] In their paper, "First Octahedral Spherical Hohlraum Energetics Experiment at the SGIII Laser Facility," published in Physical Review Letters, 2018, 120, Wen Yihuo et al. from the Institute of Applied Physics and Computing in Beijing, China, proposed a golden octahedral spherical cavity structure with six laser injection holes. This structure reduces radiation asymmetry to 0.1% and exhibits high implosion symmetry and low backscattering without the need for auxiliary techniques.

[0007] In summary, using a cavity structure to control the temperature of the deuterium-tritium pellet inside a cryogenic target offers the advantages of flexibility and ease of implementation. Either a cylindrical or spherical cavity structure can be selected based on actual needs. However, both of these structures are monolithic, making them inconvenient to assemble with the corresponding cones and difficult to adjust the cone spacing, making them unsuitable for dual-cone collision ignition cryogenic targets. Therefore, a temperature-controlled aluminum sleeve with easily controllable dimensions, easy assembly, and easily adjustable cone spacing is urgently needed, suitable for dual-cone collision ignition cryogenic targets. Summary of the Invention

[0008] In view of the defects in the prior art, the purpose of the present invention is to provide an aluminum sleeve for double-cone collision ignition of low-temperature freezing targets.

[0009] According to one aspect of the present invention, there is provided an aluminum sleeve for a double-cone collision ignition cryogenic target, comprising:

[0010] A middle aluminum sleeve, wherein the interior of the middle aluminum sleeve is a cavity;

[0011] Sealing aluminum covers, two sealing aluminum covers are respectively located at the upper and lower ends of the middle aluminum sleeve;

[0012] Sealing membrane: a sealing membrane is provided inside each sealing aluminum cover;

[0013] The middle aluminum sleeve, the sealing aluminum cover and the sealing film are sealed and connected to each other to form a columnar cavity structure model with a hollow interior.

[0014] Preferably, the column cavity structure model as a whole presents an "I"-shaped column cavity structure, and the area of ​​the helium-filled cavity at both ends is larger than the area of ​​the middle cavity.

[0015] Preferably, the middle aluminum sleeve adopts an I-shaped structure, which is provided with upper and lower tapered through holes and side symmetrical tapered holes, micro-through holes for fuel transportation, and an annular boss for cooperating with the sealing aluminum cover.

[0016] Preferably, the upper and lower conical through holes of the middle aluminum sleeve are cylindrical through holes or a structure in which a conical hole and a cylindrical through hole cooperate. The choice of structure needs to be designed according to the parameters of the central chamber space requirement and the upper and lower cone size requirements;

[0017] The symmetrical tapered holes on the side of the middle aluminum sleeve are tapered holes to achieve the fixation and positioning of the side cones, and their sizes need to be designed according to the size and requirements of the side cones.

[0018] Preferably, the sealing aluminum cover includes a top inner boss and a side outer boss surrounding the top inner boss; the side outer boss realizes the clamping of the silicon arm and the installation of the corresponding sensor; the top inner boss is used to connect the sealing membrane to enhance its pressure bearing capacity.

[0019] Preferably, the sealing film is a PI film.

[0020] Preferably, the sealing connection between the sealing film and the sealing aluminum cover is low-temperature adhesive bonding; the sealing connection between the sealing aluminum cover and the intermediate sleeve is low-temperature colloid bonding or mechanical connection.

[0021] Preferably, the mechanical structure sealing connection between the sealing aluminum cover and the intermediate sleeve adopts a card slot design.

[0022] Preferably, the sealing aluminum cover and the intermediate sleeve are processed by ultra-precision machine tools, wherein various pores are processed by micro-pore ultra-precision processing; and the sealing film is processed by ultraviolet laser cutting.

[0023] Preferably, the micro-hole ultra-precision machining methods include femtosecond laser machining, ultrasonic machining, electrochemical machining and micro-electrical discharge machining.

[0024] According to a second aspect of the present invention, there is provided a method for preparing an aluminum sleeve for a double-cone collision ignition cryogenic target, comprising:

[0025] The middle aluminum sleeve and the sealing aluminum cover are processed as a whole using ultra-precision processing methods;

[0026] Use femtosecond laser cutting equipment to complete the preparation of fuel filling holes, fuel outlet holes, and helium inlet and outlet holes in the middle sleeve;

[0027] Use picosecond laser cutting equipment to complete the cutting process of sealing film;

[0028] Observe the operation under a microscope, drop an appropriate amount of UV curing glue on the inner boss of the sealed aluminum cover and spread it evenly, apply the sealing film to the inner boss and press gently to fully bond it, and use a UV curing lamp at low power for several short periods of time to cure the UV curing glue;

[0029] Observe the operation under a microscope, drop an appropriate amount of UV curing glue on the outer edge of the middle sleeve and spread it evenly, gently apply the sealing aluminum cover to the boss and press it, use a UV curing lamp with low power for a short time multiple times to cure the UV curing glue, and complete the assembly of the aluminum sleeve; alternatively, use a toothed structure to connect the middle sleeve and the aluminum cover to complete the assembly of the aluminum sleeve.

[0030] Compared with the prior art, the embodiments of the present invention have at least one of the following beneficial effects:

[0031] The aluminum sleeve for double-cone collision ignition cryogenic target in the embodiment of the present invention is assembled from discrete units. Each part can be independently designed and processed, sealed and connected, and easy to operate, so that the overall structure has a certain degree of flexibility.

[0032] The aluminum sleeve for the double-cone collision ignition cryogenic target in the embodiment of the present invention is in an "I" shape as a whole. This structure can ensure the temperature control and sealing effect of the core chamber, thereby ensuring the thermal environment of the core target pellet. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0034] Figure 1 This is a schematic diagram of the overall structure of an aluminum sleeve for double-cone collision ignition of a cryogenic target in one embodiment of the present invention;

[0035] Figure 1 The middle mark indicates: 1 is the sealing aluminum cover, 2 is the middle sleeve, and 3 is the sealing membrane;

[0036] Figure 2 This is a schematic diagram of a middle aluminum sleeve of an aluminum sleeve used for double-cone collision ignition of a low-temperature freezing target in a preferred embodiment of the present invention;

[0037] Figure 2 The marks in the middle indicate respectively: 2-1 is the fuel inlet hole, 2-2 is the fuel outlet hole, 2-3 is the helium inlet hole, 2-4 is the helium outlet hole, 2-5 is the side cone hole, and 2-6 is the side boss structure;

[0038] Figure 3 This is a schematic diagram of a sealing aluminum cover and a sealing film of an aluminum sleeve for a double-cone collision ignition cryogenic target in a preferred embodiment of the present invention;

[0039] Figure 3 The marks in the middle indicate respectively: 1-1 is the boss structure for fixture positioning and sensor installation, 1-2 is the inner boss structure for sealing film positioning;

[0040] Figure 4This is a schematic diagram of the mechanical structure connection of an aluminum sleeve for double-cone collision ignition of a cryogenic target in a preferred embodiment of the present invention;

[0041] Figure 4 The marks in the middle indicate respectively: 4-1 is the side tooth-shaped boss structure, and 4-2 is the sealing aluminum cover positioning tooth-shaped slot structure. DETAILED DESCRIPTION

[0042] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several variations and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0043] See also Figure 1 The present invention provides an aluminum sleeve for double-cone collision ignition cryogenic targets. The sleeve comprises three parts: a sealed aluminum cover 1, an intermediate aluminum sleeve 2, and a sealing membrane 3. The intermediate aluminum sleeve 2 has a hollow interior; two sealed aluminum covers 1 are located at the upper and lower ends of the intermediate aluminum sleeve 2, respectively; and each sealed aluminum cover 2 has a sealing membrane 3 disposed therein. The intermediate aluminum sleeve 2, the sealed aluminum covers 1, and the sealing membrane 3 are sealedly connected to each other, forming a cylindrical cavity structure model with a hollow interior.

[0044] The overall structure of this embodiment is assembled from discrete units, each part can be independently designed and processed, sealed and connected, and easy to operate, so that the overall structure has a certain degree of flexibility.

[0045] See also Figure 2 In a preferred embodiment of the present invention, a preferred structure of the middle aluminum sleeve 2 is provided. In order to ensure the temperature control effect of the core chamber and eliminate the influence of other gases, the design adopts an "I"-shaped structure. In order to ensure the filling of the fuel, a fuel inlet hole 2-1 is set according to the position of the cone, and the deuterium-tritium fuel gas will enter the core chamber along the inlet hole 2-1 and fill the upper and lower cones. In order to balance the internal pressure of the core chamber, a fuel outlet hole 2-2 is set. Since the middle core chamber is a connected structure, it is sufficient to set a fuel outlet hole. In order to provide a fuel liquefaction infiltration environment, helium inlet holes 2-3 are set at the bottom and top chambers, such as Figure 2 As described in (a), helium is filled into the space between the aluminum cover and the middle aluminum sleeve along the helium inlet. To balance the pressure, helium outlet holes 2-4 are set on the back of the inlet hole. Since the two parts are not connected to each other, they need to be set up independently. Figure 2 As shown in (b). The filling gas flow is as follows Figure 2As shown in (c), the fuel gas enters the core cavity along the micro-through hole 2-1 and flows out along the micro-through hole 2-2; helium enters through the micro-through hole 2-3 and flows out through the opposite micro-through hole 2-4. To achieve the installation and positioning of the side cone and ensure the sealing effect, the side cone hole 2-5 adopts a conical hole that matches the side cone; to achieve the installation and positioning of the main cone and ensure the sealing effect, a through hole combining conical and cylindrical shapes is used between the top chamber and the middle core chamber, as shown in FIG. Figure 2 As shown in the cross-sectional view in the middle (c); in order to realize the connection between the middle aluminum sleeve and the sealing aluminum cover and ensure the sealing effect, a boss 2-6 structure is set on the outside of the middle aluminum sleeve.

[0046] The middle aluminum sleeve of this embodiment is in the shape of an "I" as a whole. This structure can ensure the temperature control and sealing effect of the core chamber, thereby ensuring the thermal environment of the core target pellet.

[0047] In a preferred embodiment, the upper and lower conical through holes of the middle aluminum sleeve are cylindrical through holes or a conical hole and a cylindrical through hole. The choice of structure needs to be designed according to the parameters of the central chamber space requirements and the upper and lower cone size requirements.

[0048] The upper and lower conical holes can be simple cylindrical through-holes, but this design would increase the central cavity space and make temperature control difficult. Therefore, a composite structure can be used: a conical hole in the upper half and a cylindrical hole in the lower half. The conical portion also serves as a limiter. Due to the micropores for fuel transportation, all conical holes cannot be used; otherwise, the sidewalls would be too thick to machine the micropores. The symmetrical conical holes on the side of the central aluminum sleeve are tapered to secure and position the side cones. Their dimensions must be designed based on the size and requirements of the side cones.

[0049] See also Figure 3 In a preferred embodiment of the present invention, a preferred structure of a sealing aluminum cover 1 and a sealing film 3 is provided. The sealing aluminum cover 1 mainly includes an external boss structure 1-1 to achieve the positioning and clamping effect of the fixture. In order to achieve precise temperature conduction and temperature control, the size of the boss structure needs to be optimized and the thickness is 200-450nm. Figure 3 In order to ensure the positioning of the sealing film, improve the pressure resistance of the sealing film and ensure the sealing of the structure, an inner boss structure 1-2 is provided on the top of the sealing aluminum cover, as shown in (a); Figure 3 As shown in (b); the sealing film 3 is a cylindrical polymer film with a certain thickness, such as Figure 3 As shown in (c).

[0050] In a preferred embodiment of the present invention, the sealing aluminum cover and the intermediate sleeve are processed by ultra-precision machine tools, wherein the air filling holes are processed by micro-pore ultra-precision processing; and the sealing film is processed by ultraviolet laser cutting.

[0051] In a preferred embodiment, the micro-hole ultra-precision machining methods include but are not limited to femtosecond laser machining, ultrasonic machining, electrochemical machining and micro-EDM.

[0052] In a preferred embodiment of the invention, the sealing connection between the sealing film and the sealing aluminum cover includes but is not limited to the use of low-temperature glue; the sealing connection between the sealing aluminum cover and the intermediate sleeve includes but is not limited to the use of low-temperature colloid bonding or mechanical connection.

[0053] In a preferred embodiment, see Figure 4 In order to realize the mechanical connection between the middle aluminum sleeve 2 and the sealing aluminum cover 1, a snap-fit ​​design is adopted: the middle sleeve is provided with a toothed boss structure 4-1 with an arc of 90 degrees, and a 90-degree gap is left between adjacent structures, such as Figure 4 As shown in (a); the sealed aluminum cover is provided with a slot structure 4-2 with an arc of 90 degrees, and a 90-degree gap is left between adjacent structures, as shown in FIG. Figure 4 As shown in (b).

[0054] In other embodiments of the present invention, a method for preparing an aluminum sleeve for a double-cone collision ignition cryogenic target is provided.

[0055] Example 1

[0056] In this embodiment, an aluminum sleeve connected by sealant for double-cone collision ignition cryogenic target is prepared by the following steps:

[0057] 1) The middle aluminum sleeve and the sealing aluminum cover are processed as a whole using ultra-precision processing methods;

[0058] 2) Using femtosecond laser cutting equipment to complete the preparation of fuel filling holes, fuel outlet holes, and helium inlet and outlet holes in the middle sleeve;

[0059] 3) Using picosecond laser cutting equipment to complete the cutting process of the sealing film;

[0060] 4) Observe the operation under a microscope. Add an appropriate amount of UV curing glue to the inner boss of the sealed aluminum cover and spread it evenly. Apply the sealing film to the inner boss and press gently to completely bond it. Use a UV curing lamp at low power for several short periods of time to cure the UV curing glue.

[0061] 5) Observe the operation under a microscope, drop an appropriate amount of UV curing glue on the outer edge of the middle sleeve and spread it evenly, gently apply the sealing aluminum cover to the boss and press it, use a UV curing lamp with low power for a short time multiple times to cure the UV curing glue, and complete the assembly of the aluminum sleeve.

[0062] Example 2

[0063] In this embodiment, an aluminum sleeve for igniting a low-temperature freezing target with a double-cone collision is prepared using a mechanical structure. The preparation process includes the following steps:

[0064] 1) The middle aluminum sleeve and the sealing aluminum cover are processed as a whole using ultra-precision processing methods;

[0065] 2) Using femtosecond laser cutting equipment to complete the preparation of fuel filling holes, fuel outlet holes, and helium inlet and outlet holes in the middle sleeve;

[0066] 3) Using picosecond laser cutting equipment to complete the cutting process of the sealing film;

[0067] 4) Observe the operation under a microscope. Add an appropriate amount of UV curing glue to the inner boss of the sealed aluminum cover and spread it evenly. Apply the sealing film to the inner boss and press gently to completely bond it. Use a UV curing lamp at low power for several short periods of time to cure the UV curing glue.

[0068] 5) Observe the operation under a microscope and use the toothed structure to connect the middle sleeve and the aluminum cover to complete the assembly of the aluminum sleeve.

[0069] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various modifications or variations within the scope of the claims without affecting the essence of the present invention. The above preferred features may be used in any combination as long as they do not conflict with each other.

Claims

1. An aluminum sleeve for double-cone collision ignition cryogenic target, characterized in that: include: A middle aluminum sleeve, wherein the interior of the middle aluminum sleeve is a cavity; Sealing aluminum covers, two sealing aluminum covers are respectively located at the upper and lower ends of the middle aluminum sleeve; Sealing membrane: a sealing membrane is provided inside each sealing aluminum cover; The middle aluminum sleeve, the sealing aluminum cover and the sealing membrane are sealed and connected to each other to form a columnar structure model with a hollow interior; The sealing aluminum cover includes a top inner boss and a side outer boss surrounding the top inner boss; the side outer boss realizes the clamping of the silicon arm and the installation of the corresponding sensor; the top inner boss is used to connect the sealing membrane to enhance its pressure bearing capacity.

2. The aluminum sleeve for double-cone collision ignition cryogenic target according to claim 1, characterized in that: The column cavity structure model as a whole presents an "I"-shaped column cavity structure, and the area of ​​the helium cavity filled at both ends is larger than the area of ​​the middle cavity.

3. The aluminum sleeve for double-cone collision ignition cryogenic target according to claim 1, characterized in that: The middle aluminum sleeve adopts an "I"-shaped structure, which is provided with upper and lower conical through holes and side symmetrical conical holes, a micro-through hole 1 for fuel transportation, a micro-through hole 2 for helium transportation, and an annular boss for cooperating with the sealing aluminum cover.

4. The aluminum sleeve for double-cone collision ignition cryogenic target according to claim 3, characterized in that: The upper and lower conical through holes of the middle aluminum sleeve are cylindrical through holes or a conical hole and a cylindrical through hole. The structure of the middle aluminum sleeve is designed according to the parameters of the central chamber space requirements and the upper and lower cone size requirements; The symmetrical tapered holes on the side of the middle aluminum sleeve are tapered holes to achieve the fixation and positioning of the side cones, and their sizes are designed according to the size and requirements of the side cones; The micro-through hole for fuel transportation is a cylindrical through hole with a diameter of 5-50 μm; The second micro-through hole for helium transportation is a cylindrical through hole with a diameter of hundreds of microns.

5. The aluminum sleeve for double-cone collision ignition cryogenic target according to claim 1, characterized in that: The sealing film is a PI film whose transmittance is adapted to a 350 nm laser wavelength.

6. The aluminum sleeve for double-cone collision ignition cryogenic target according to claim 1, characterized in that: The sealing connection between the sealing film and the sealing aluminum cover is low-temperature adhesive bonding; the sealing connection between the sealing aluminum cover and the middle aluminum sleeve adopts low-temperature colloid bonding or mechanical connection; wherein the mechanical connection includes a slot connection.

7. The aluminum sleeve for double-cone collision ignition cryogenic target according to claim 3, characterized in that: The sealing aluminum cover and the middle aluminum sleeve are processed by ultra-precision machine tools, wherein various pores are processed by micro-pore ultra-precision processing; the sealing film is processed by ultraviolet laser cutting.

8. The aluminum sleeve for double-cone collision ignition cryogenic target according to claim 7, characterized in that: The micro-hole ultra-precision machining methods include femtosecond laser machining, ultrasonic machining, electrochemical machining and micro-electrical discharge machining.

9. A method for preparing an aluminum sleeve for a double-cone collision ignition cryogenic target according to any one of claims 1 to 8, characterized in that: include: The middle aluminum sleeve and the sealing aluminum cover are processed as a whole using ultra-precision processing methods; Use femtosecond laser cutting equipment to complete the preparation of fuel filling holes, fuel outlet holes, and helium inlet and outlet holes on the middle aluminum sleeve; Use picosecond laser cutting equipment to complete the cutting process of sealing film; Observe the operation under a microscope, drop an appropriate amount of UV curing glue on the inner boss of the sealed aluminum cover and spread it evenly, apply the sealing film to the inner boss and press gently to fully bond it, and use a UV curing lamp at low power for several short periods of time to cure the UV curing glue; Observe the operation under a microscope, drop an appropriate amount of UV curing glue on the outer edge of the middle aluminum sleeve and spread it evenly, gently apply the sealing aluminum cover to the boss and press it, use a UV curing lamp with low power for multiple short times to cure the UV curing glue, and complete the assembly of the aluminum sleeve; alternatively, use a toothed structure to connect the middle aluminum sleeve and the aluminum cover to complete the assembly of the aluminum sleeve.

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