Gravity and micro-nano structure enhanced thermosyphon radiator and preparation method thereof

Abstract

The invention discloses a gravity and micro-nano structure enhanced thermosyphon radiator and a preparation method thereof, and belongs to the field of thermosyphon radiators, the structure of the thermosyphon radiator comprises a heat absorption end bottom plate, a heat dissipation mechanism is arranged at the top end of the heat absorption end bottom plate, fixing mechanisms are arranged on the two sides and the upper portion of the heat dissipation mechanism, and the heat absorption end bottom plate is of a box-shaped structure; positioning bolt holes are formed in the four corners of the heat absorption end bottom plate, a heat absorption end supporting column and a heat absorption end inner wall face strengthening structure are arranged in the heat absorption end bottom plate, and a pumping and injecting opening is formed in the box wall on one side of the heat absorption end bottom plate. By the adoption of the structure and the method, the problems that at present, a traditional thermosiphon is single in steam diffusion direction and limited in effective heat dissipation area expansion, heat transfer deterioration is advanced due to the fact that a boiling heat transfer process of a smooth surface lacks a vaporization core and is weak in rewetting capacity, and the heat dissipation requirement of a high-heat-flow chip cannot be met are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of thermosyphon radiators, and in particular to a gravity and micro-nano structure enhanced thermosyphon radiator and a preparation method thereof. Background Art

[0002] With the development of technologies such as 5G communications and artificial intelligence, the society's demand for computing power has increased dramatically, and high-performance chips have been continuously launched, but this also brings about the problem of heat dissipation with high heat flux density. Traditional pure solid-state air-cooled radiators have high thermal resistance, large volume and weight, and can no longer meet the heat dissipation needs of current and even future high-performance chips. Although the direct liquid cooling technology based on immersion and the indirect liquid cooling technology based on cold plates have higher heat dissipation efficiency, they have problems such as high investment and operation and maintenance costs and complex systems. The latter's coolant leakage problem poses a greater challenge to the cooling system. Therefore, fully tapping the potential of air cooling technology still has high engineering application value.

[0003] In recent years, air-cooled array heat pipes, two-phase temperature equalizers, thermosiphons and other technologies have been developed based on heat pipes. The superconducting advantages of heat pipes have been utilized to greatly increase the effective heat dissipation area, and they have significant advantages such as strong heat dissipation capacity, low thermal resistance, and good temperature uniformity. Among them, array heat pipes and two-phase temperature equalizers both show high heat dissipation efficiency and low thermal resistance. However, the internal working fluid circulation requires the preparation of porous capillary structures through a sintering process to provide capillary force, which is a complex process and has high manufacturing costs. Although thermosiphons rely on gravity to achieve working fluid circulation, they have the advantages of simple structure and reliable performance.

[0004] However, traditional thermosiphons are mostly two-dimensional single-direction circulation working modes, which results in a single direction of steam diffusion. The heat exchange fins can only be arranged on a single channel, and the effective heat dissipation area is limited. At the same time, the thermosiphon relies on the boiling-condensation heat transfer of the internal working fluid to transfer heat. The boiling thermal resistance and condensation thermal resistance generally only account for 50-70% of the total thermal resistance. On the other hand, the boiling heat transfer process on the smooth surface lacks a vaporization core and has weak rewetting ability, which can easily lead to premature deterioration of heat transfer and cannot meet the heat dissipation requirements of high heat flux chips. Summary of the invention

[0005] The purpose of the present invention is to provide a gravity and micro-nano structure enhanced thermosiphon heat sink and its preparation method, so as to solve the problems that the current traditional thermosiphon has a single vapor diffusion direction, limited effective heat dissipation area expansion, and the boiling heat transfer process on the smooth surface lacks a vaporization core and weak rewetting ability, which leads to premature heat transfer deterioration and cannot meet the heat dissipation requirements of high heat flux chips.

[0006] To achieve the above-mentioned objectives, the present invention provides a gravity and micro-nano structure enhanced thermosyphon radiator, comprising a heat absorbing end base plate, a heat dissipation mechanism is arranged on the top of the heat absorbing end base plate, fixing mechanisms are arranged on both sides and above the heat dissipation mechanism, the heat absorbing end base plate is a box-shaped structure, positioning bolt holes are arranged at the four corners of the heat absorbing end base plate, a heat absorbing end support column and a heat absorbing end inner wall reinforcement structure are arranged inside the heat absorbing end base plate, and a pumping port is arranged on the box wall on one side of the heat absorbing end base plate.

[0007] Preferably, the inner wall reinforcement structure of the heat absorbing end is arranged at the central position of the heat absorbing end bottom plate, the heat absorbing end support columns are evenly distributed around the inner wall reinforcement structure of the heat absorbing end, and the bottom ends of the heat absorbing end support columns are fixedly connected to the heat absorbing end bottom plate.

[0008] Preferably, the inner wall reinforcement structure of the heat absorbing end includes a plurality of microneedle fins, and a plurality of nano-hole structures are distributed on the surface of the microneedle fins, the surface of the heat absorbing end support column and the inner surface of the heat absorbing end bottom plate, and the bottom end of the microneedle fin is fixedly connected to the heat absorbing end bottom plate.

[0009] Preferably, the heat dissipation mechanism includes a heat absorbing end assembly partition and a heat releasing end assembly partition, a plurality of drawer-type multi-layer fins and a plurality of steam diffusion flat tubes are alternately arranged in the middle of the heat absorbing end assembly partition and the heat releasing end assembly partition, and the heat absorbing end assembly partition and the top end of the heat absorbing end support column are welded.

[0010] Preferably, the interior of the steam diffusion flat tube is hollow to form a steam diffusion channel, and a plurality of heat release end double-stage radial ridge micro-groove structures are arranged on the inner wall of the steam diffusion flat tube. The heat release end double-stage radial ridge micro-groove structures are arranged in parallel in the transverse direction on the inner wall surface of the steam diffusion flat tube, and the heat release end double-stage radial ridge micro-groove structure includes two levels of concave grooves along the height direction, the tangent angle of the envelope line of the first-level concave groove is α, and the tangent angle of the envelope line of the second-level concave groove is β, and α>β.

[0011] Preferably, the fixing mechanism includes a top fixing plate and two side fixing plates, and the top fixing plate, the side fixing plates, the heat absorption end assembly partition and the heat release section assembly partition are integrally welded to form a connected closed cavity.

[0012] The present invention also includes a method for preparing a gravity and micro-nanostructure enhanced thermosiphon radiator: various structural components are manufactured by machine tool processing, slots are machined into the heat absorbing end assembly partition and the heat releasing end assembly partition after the manufacturing is completed, and then the steam diffusion flat tube is inserted between the slots of the heat absorbing end assembly partition and the heat releasing end assembly partition, and the outer sides of the slots are welded, and at the same time, drawer-type multi-layer fins are installed on both sides of each steam diffusion flat tube, and then a top fixing plate is welded on the heat releasing end assembly partition, and side fixing plates are welded on both sides of the top fixing plate, and the lower side of the side fixing plate is connected to the heat absorbing end assembly partition and the heat absorbing end bottom plate, and the whole is welded and sealed.

[0013] Preferably, the length, width and height of the heat absorbing end support column are all 2-4 mm, the spacing between adjacent heat absorbing end support columns is 2-4 mm, and the side fixing plates, drawer-type multi-layer fins, heat releasing end assembly partitions and top fixing plates are all prepared by cutting aluminum alloy plates.

[0014] Preferably, the microneedle fins are arranged in an array in a columnar structure, the characteristic size of the column is 50-500 μm, the height is 50-800 μm, and the processing process is:

[0015] Step 1: Clean and dry the microneedle fins using anhydrous, acetone, and deionized water;

[0016] Step 2: Use femtosecond laser to process the microneedle fins. The power of the femtosecond laser is 5-15W, the scanning speed is 20-150mm / s, the processing frequency is 50-200kHZ, and the number of processing times is 2-5 times;

[0017] Step 3: Clean again using the method in step 1 and place in a dry place;

[0018] The nano-hole structure is evenly distributed on the surface of the micro-needle fin, the surface of the heat-absorbing end support column and the inner surface of the heat-absorbing end bottom plate, and the characteristic size of the nano-hole is 0.1-1 μm.

[0019] Preferably, the preparation method of the double-stage radial ridge microgroove structure at the heat release end is to design and prepare a stainless steel mold according to the outer contour dimensions of the double-stage radial ridge microgroove structure at the heat release end, and then place the aluminum alloy plate on the mold for extrusion, and then obtain the double-stage radial ridge microgroove structure of the heat release end with a corresponding mold shape. The height of the double-stage radial ridge microgroove structure at the heat release end is 0.5-2mm, the maximum width is 2-3mm, and the center axis spacing is 4-6mm.

[0020] Therefore, the present invention adopts a gravity and micro-nano structure enhanced thermosiphon radiator and a preparation method thereof using the above structure, which has the following beneficial effects:

[0021] 1. By upgrading the working mode of the traditional thermosyphon from two-dimensional to three-dimensional, the extensive diffusion of steam in multi-dimensional space is achieved. This transformation greatly expands the steam condensation heat exchange area, thereby improving the heat exchange efficiency of the heat release end of the thermosyphon;

[0022] 2. Drawing on the exquisite features of the microscopic double-stage radial ridge structure on the surface of the leaf lip of Nepenthes in nature, an innovative bionic design was made for the inner wall of the heat release end of the thermosyphon, which cleverly restricted the direction of the meniscus of the condensate film, allowing the condensate to gather in an orderly manner at the bottom of the micro-groove, thereby effectively controlling the upper limit of the liquid film thickness, allowing the condensate to flow quickly to the boiling side, and also increasing the structural area of ​​the inner wall surface on the steam and heat release side, further improving the performance of the thermosyphon;

[0023] 3. A micro-needle fin-nano-hole composite structure is set on the inner wall of the heat absorption end. The nano-hole structure provides a large number of vaporization cores to improve the boiling enhanced heat transfer coefficient; the micro-needle fin provides a micro-liquid layer flow channel in the evaporation zone to increase the critical heat flux density of boiling heat transfer, thereby improving the heat exchange efficiency of the boiling side of the thermosiphon;

[0024] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic structural diagram of an embodiment of a gravity and micro-nanostructure enhanced thermosyphon radiator of the present invention;

[0026] Figure 2 An exploded schematic diagram of an embodiment of a thermosyphon heat sink enhanced by gravity and micro-nano structures of the present invention;

[0027] Figure 3 It is a structural schematic diagram of a gravity and micro-nano structure enhanced thermal siphon heat sink embodiment of the present invention, which has an inner wall surface reinforcement structure at the heat absorption end;

[0028] Figure 4 A schematic diagram of the distribution of micro-needle fins and nano-cavity structures of a thermosiphon heat sink embodiment of the present invention enhanced by gravity and micro-nano structures;

[0029] Figure 5 It is a schematic oblique structural diagram of a steam diffusion flat tube of a thermosiphon radiator embodiment enhanced by gravity and micro-nano structures of the present invention;

[0030] Figure 6 This is a structural schematic diagram of the double-stage radial ridge microgrooves at the heat release end of a gravity and micro-nanostructure enhanced thermosiphon radiator embodiment of the present invention.

[0031] Reference numerals

[0032] 1. Heat absorbing end bottom plate; 110. Heat absorbing end support column; 111. Positioning bolt hole; 112. Injection port; 113. Heat absorbing end inner wall reinforcement structure; 1130. Micro-needle fin; 1131. Nano-hole structure; 2. Heat absorbing end assembly partition; 3. Steam diffusion flat tube; 310. Steam diffusion channel; 311. Double-stage radial ridge micro groove at the heat release end; 4. Side fixing plate; 5. Drawer-type multi-layer fin; 6. Heat release end assembly partition; 7. Top fixing plate. Example

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0036] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0037] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "setting", "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0039] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0040] The specific model specifications need to be selected and determined based on the actual specifications of the device, and the specific selection calculation method adopts the existing technology in this field, so it will not be described in detail.

[0041] like Figure 1 to Figure 2 As shown, the present invention provides a gravity and micro-nano structure enhanced thermosyphon radiator, including a heat absorbing end base plate 1, a heat dissipation mechanism is arranged on the top of the heat absorbing end base plate 1, fixing mechanisms are arranged on both sides and above the heat dissipation mechanism, the heat absorbing end base plate 1 is a box-shaped structure, positioning bolt holes 111 are arranged at the four corners of the heat absorbing end base plate 1, a heat absorbing end support column 110 and a heat absorbing end inner wall reinforcement structure 113 are arranged inside the heat absorbing end base plate 1, and a pumping port 112 is arranged on the box wall on one side of the heat absorbing end base plate 1.

[0042] The lower surface of the heat-absorbing end base plate 1 is bonded to the chip through the thermal interface material, and is positioned and fastened by positioning bolts. The suction port 112 can be connected to the suction pipe to perform vacuum and liquid injection operations on the radiator.

[0043] The heat absorbing end inner wall reinforcement structure 113 is arranged at the central position of the heat absorbing end bottom plate 1 , the heat absorbing end support columns 110 are evenly distributed around the heat absorbing end inner wall reinforcement structure 113 , and the bottom ends of the heat absorbing end support columns 110 are fixedly connected to the heat absorbing end bottom plate 1 .

[0044] The heat dissipation mechanism includes a heat absorbing end assembly partition 2 and a heat releasing end assembly partition 6, a plurality of drawer-type multilayer fins 5 and a plurality of steam diffusion flat tubes 3 are staggered between the heat absorbing end assembly partition 2 and the heat releasing end assembly partition 6, and the heat absorbing end assembly partition 2 and the top end of the heat absorbing end support column 110 are welded.

[0045] The heat-absorbing end support column 110 is a square column, and the top is connected and fixed to the heat-absorbing end assembly partition 2 by a brazing process to improve the pressure-bearing capacity and prevent deformation caused by excessive internal pressure of the radiator.

[0046] The fixing mechanism comprises a top fixing plate 7 and two side fixing plates 4. The top fixing plate 7, the side fixing plates 4, the heat absorption end assembly partition 2 and the heat release section assembly partition are integrally welded to form a connected closed cavity.

[0047] like Figure 3 As shown, the heat absorbing end inner wall surface reinforcement structure 113 includes a plurality of micro-needle fins 1130, and a plurality of nano-hole structures 1131 are distributed on the surface of the micro-needle fins 1130, the surface of the heat absorbing end support column 110, and the inner surface of the heat absorbing end bottom plate 1, and the bottom end of the micro-needle fin 1130 is fixedly connected to the heat absorbing end bottom plate 1. The specific structure of the nano-hole structure is a pit with a scale of tens of nanometers, and the specific size is related to the process flow and actual needs.

[0048] The microneedle fins 1130 can greatly increase the specific surface area of ​​the upper surface of the heat-absorbing end bottom plate 1; in addition, the array-arranged microneedle fins 1130 can provide capillary force, increase the liquid replenishment capacity of the heat exchange surface, delay the deterioration of boiling heat transfer on the upper surface of the heat-absorbing end bottom plate 1, and increase the critical heat flux density; the nano-hole structure 1131 can provide a large number of boiling vaporization cores, significantly improve the boiling heat transfer coefficient, and thus effectively reduce the thermal resistance of the radiator.

[0049] like Figure 4 As shown, the steam diffusion flat tube 3 includes a steam diffusion channel 310 and a heat release end double-stage radial ridge micro groove 311 structure, a plurality of heat release end double-stage radial ridge micro groove 311 structures are arranged in parallel on the inner wall surface of the steam diffusion flat tube 3 in the transverse direction, and the heat release end double-stage radial ridge micro groove 311 structure includes two levels of concave grooves in the height direction, the first level of concave groove envelope tangent angle is α, and the second level of concave groove envelope tangent angle is β. α>β, that is, the characteristic size of the second level of concave groove is smaller than the characteristic size of the first level of concave groove.

[0050] Under such a structure, the second-stage concave groove can form a larger capillary force. Driven by the capillary force gradient, the condensate automatically moves from the top to the bottom of the double-stage radial ridge micro-groove structure and gathers, which can not only reduce the thickness of the condensate film on the top of the double-stage radial ridge micro-groove structure and improve the condensation heat exchange efficiency, but also increase the weight of the condensate at the bottom of the double-stage radial ridge micro-groove structure, prompting the condensate to quickly fall off and flow to the upper surface of the heat-absorbing end bottom plate 1, forming a rapid liquid replenishment and improving the ultimate heat dissipation capacity of the radiator. The double-stage radial ridge micro-groove structure can greatly expand the effective condensation area of ​​the inner wall of the steam diffusion flat tube 3, improve the condensation efficiency, and reduce the thermal resistance of the radiator.

[0051] The above components are all made of aluminum alloy.

[0052] The working principle of the radiator is as follows: liquid working medium is sealed inside the radiator, mainly concentrated in the chamber between the heat-absorbing end bottom plate 1 and the heat-absorbing end assembly partition 2. The lower surface of the heat-absorbing end bottom plate 1 fits with the chip, and the positioning bolt hole 111 is used to find the position and tighten it to ensure its fit and facilitate heat transfer. After the heat-absorbing end bottom plate 1 absorbs the heat of the chip, the liquid working medium boils and vaporizes on the upper surface of the heat-absorbing end bottom plate 1, and the generated steam diffuses upward to the internal flow channel of the steam diffusion flat tube 3. The heat is conducted to the fin surface of the drawer-type multi-layer fin 5 through the wall of the steam diffusion flat tube 3, and then heat is exchanged with the air. After the steam releases heat, it condenses and liquefies and turns back into liquid working medium. Then, the liquid working medium flows back to the chamber of the heat-absorbing end bottom plate 1 under the action of gravity to continue boiling, and so on.

[0053] The liquid working fluid inside the radiator can be a low boiling point refrigerant, such as R134a, R245fa or R1233zd (E), or a low boiling point fluorinated coolant (boiling point 10-65°C), such as HFE-7100, Novec649, or an alcohol working fluid, such as methanol, ethanol, etc.

[0054] The present invention also provides a method for preparing a gravity and micro-nano structure enhanced thermosiphon radiator, wherein each structural component is manufactured by machine tool processing, slots are machined into the heat absorbing end assembly partition 2 and the heat releasing end assembly partition 6 after the manufacturing is completed, and then the steam diffusion flat tube 3 is inserted between the slots of the heat absorbing end assembly partition 2 and the heat releasing end assembly partition 6, and the outer sides of the slots are welded, and at the same time, drawer-type multi-layer fins 5 are installed on both sides of each steam diffusion flat tube 3, and then a top fixing plate 7 is welded on the heat releasing end assembly partition 6, and side fixing plates 4 are welded on both sides of the top fixing plate 7, and the lower side of the side fixing plate 4 is connected to the heat absorbing end assembly partition 2 and the heat absorbing end bottom plate 1, and the whole is welded and sealed.

[0055] The length, width and height of the heat absorbing end support column 110 are all 2-4 mm, the spacing between adjacent heat absorbing end support columns 110 is 2-4 mm, and the side fixing plate 4, drawer-type multi-layer fins 5, heat releasing end assembly partition 6 and top fixing plate 7 are all prepared by cutting aluminum alloy plates.

[0056] The microneedle fin 1130 is a columnar structure arranged in an array, the characteristic size of the column is 50-500μm, the height is 50-800μm, and the processing process is:

[0057] Step 1: Clean and dry the microneedle fin 1130 using anhydrous water, acetone and deionized water;

[0058] Step 2: Use a femtosecond laser to process the microneedle fin 1130, the power of the femtosecond laser is 5-15W, the scanning speed is 20-150mm / s, the processing frequency is 50-200kHZ, and the number of processing times is 2-5 times;

[0059] Step 3: Clean again using the method in step 1 and place in a dry place;

[0060] The nano-hole structures 1131 are evenly distributed on the surface of the micro-needle fins 1130 , the surface of the heat-absorbing end support column 110 and the inner surface of the heat-absorbing end bottom plate 1 , and the characteristic size of the nano-holes is 0.1-1 μm.

[0061] Preferably, the preparation method of the double-stage radial ridge microgroove 311 structure at the heat release end is to design and prepare a stainless steel mold according to the outer contour dimensions of the double-stage radial ridge microgroove 311 structure at the heat release end, and then use an extrusion process to prepare it. The height of the double-stage radial ridge microgroove 311 structure at the heat release end is 0.5-2mm, the maximum width is 2-3mm, and the center axis spacing is 4-6mm.

[0062] Therefore, the present invention adopts a gravity and micro-nano structure enhanced thermosiphon heat sink and its preparation method of the above-mentioned structure, which solves the problems of the current traditional thermosiphon tube having a single vapor diffusion direction, limited effective heat dissipation area expansion, and the boiling heat transfer process on the smooth surface lacking a vaporization core and weak rewetting ability, which leads to premature heat transfer deterioration and cannot meet the heat dissipation requirements of high heat flux chips.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A gravity and micro-nano structure enhanced thermosyphon radiator, characterized in that: It includes a heat absorbing end base plate, a heat dissipation mechanism is arranged on the top of the heat absorbing end base plate, fixing mechanisms are arranged on both sides and the top of the heat dissipation mechanism, the heat absorbing end base plate is a box-shaped structure, positioning bolt holes are arranged at the four corners of the heat absorbing end base plate, a heat absorbing end support column and a heat absorbing end inner wall reinforcement structure are arranged inside the heat absorbing end base plate, and a pumping port is arranged on the box wall on one side of the heat absorbing end base plate.

2. The gravity and micro-nanostructure enhanced thermosyphon radiator according to claim 1, characterized in that: The heat absorbing end inner wall reinforcement structure is arranged at the central position of the heat absorbing end bottom plate, the heat absorbing end support columns are evenly distributed around the heat absorbing end inner wall reinforcement structure, and the bottom ends of the heat absorbing end support columns are fixedly connected to the heat absorbing end bottom plate.

3. The gravity and micro-nanostructure enhanced thermosyphon radiator according to claim 1, characterized in that: The inner wall reinforcement structure of the heat absorbing end includes a plurality of micro-needle fins. The surface of the micro-needle fins, the surface of the heat absorbing end support column and the inner surface of the heat absorbing end bottom plate are all distributed with a plurality of nano-hole structures. The bottom end of the micro-needle fin is fixedly connected to the heat absorbing end bottom plate.

4. The gravity and micro-nanostructure enhanced thermosyphon radiator according to claim 1, characterized in that: The heat dissipation mechanism includes a heat absorbing end assembly partition and a heat releasing end assembly partition. A plurality of drawer-type multi-layer fins and a plurality of steam diffusion flat tubes are staggered between the heat absorbing end assembly partition and the heat releasing end assembly partition. The heat absorbing end assembly partition and the top end of the heat absorbing end support column are welded.

5. The gravity and micro-nanostructure enhanced thermosyphon radiator according to claim 4, characterized in that: The interior of the steam diffusion flat tube is hollow to form a steam diffusion channel. A plurality of heat release end double-stage radial ridge micro-groove structures are arranged on the inner wall of the steam diffusion flat tube. The heat release end double-stage radial ridge micro-groove structures are arranged in parallel on the inner wall surface of the steam diffusion flat tube in the transverse direction. The heat release end double-stage radial ridge micro-groove structure includes two levels of concave grooves along the height direction. The tangent angle of the envelope line of the first-level concave groove is α, and the tangent angle of the envelope line of the second-level concave groove is β, and α>β.

6. The gravity and micro-nanostructure enhanced thermosyphon radiator according to claim 4, characterized in that: The fixing mechanism comprises a top fixing plate and two side fixing plates. The top fixing plate, the side fixing plates, the heat absorption end assembly partition and the heat release section assembly partition are integrally welded to form a connected closed cavity.

7. A method for preparing a gravity and micro-nanostructure enhanced thermosyphon radiator according to any one of claims 1 to 6, characterized in that: The various structural components are manufactured by machine tools, and slots are processed into the finished heat absorption end assembly partition and the heat release end assembly partition. The finished steam diffusion flat tube is then inserted between the slots of the heat absorption end assembly partition and the heat release end assembly partition, and the outer sides of the slots are welded. At the same time, drawer-type multi-layer fins are installed on both sides of each steam diffusion flat tube, and then the top fixing plate is welded to the heat release end assembly partition, and the side fixing plates are welded on both sides of the top fixing plate. The lower side of the side fixing plate is connected to the heat absorption end assembly partition and the heat absorption end bottom plate, and the whole is welded and sealed.

8. The method for preparing a gravity and micro-nanostructure enhanced thermosyphon radiator according to claim 7, characterized in that: The length, width and height of the heat absorbing end support column are all 2-4mm, the spacing between adjacent heat absorbing end support columns is 2-4mm, and the side fixing plates, drawer-type multi-layer fins, heat releasing end assembly partitions and top fixing plates are all prepared by cutting aluminum alloy plates.

9. The method for preparing a gravity and micro-nanostructure enhanced thermosyphon radiator according to claim 7, characterized in that: The microneedle fins are columnar structures arranged in an array. The characteristic size of the column is 50-500μm and the height is 50-800μm. The processing process is as follows: Step 1: Clean and dry the microneedle fins using anhydrous, acetone, and deionized water; Step 2: Use femtosecond laser to process the microneedle fins. The power of the femtosecond laser is 5-15W, the scanning speed is 20-150mm / s, the processing frequency is 50-200kHZ, and the number of processing times is 2-5 times; Step 3: Clean again using the method in step 1 and place in a dry place; The nano-hole structure is evenly distributed on the surface of the micro-needle fin, the surface of the heat-absorbing end support column and the inner surface of the heat-absorbing end bottom plate, and the characteristic size of the nano-hole is 0.1-1 μm.

10. The method for preparing a gravity and micro-nanostructure enhanced thermosyphon radiator according to claim 7, characterized in that: The preparation method of the double-stage radial ridge microgroove structure at the heat release end is to design and prepare a stainless steel mold according to the outer contour size of the double-stage radial ridge microgroove structure at the heat release end, and then place the aluminum alloy plate on the mold for extrusion, and then obtain the double-stage radial ridge microgroove structure of the heat release end with a corresponding mold shape. The height of the double-stage radial ridge microgroove structure at the heat release end is 0.5-2mm, the maximum width is 2-3mm, and the center axis spacing is 4-6mm.

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