High-performance wick with micro-nano composite holes for heat pipe and heat pipe thereof

Abstract

The utility model discloses a high-performance wick with micro-nano composite holes for a heat pipe and the heat pipe with the wick. The wick is formed by arranging a plurality of matrix units in an array mode, and micron-scale holes and nano-scale holes are formed in the matrix units. The base body unit is a hollow cube, the micron-sized holes penetrate from the center of one surface to the center of the opposite surface, the nano-sized holes are distributed around the periphery of the micron-sized holes, and the nano-sized holes extend in the direction of one surface facing the opposite surface and are communicated with the micron-sized holes; and the micron-scale holes and the nano-scale holes of the adjacent matrix units are communicated with each other. The manufactured micro-nano composite hole wick is applied to a heat pipe, the capillary suction effect of a working medium can be enhanced, and therefore the heat transfer and mass transfer performance of the heat pipe is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of heat pipes, and particularly relates to a high-performance wick with micro-nano composite pores for a heat pipe and a heat pipe thereof. Background Technique

[0002] Due to its extremely high thermal conductivity, good isothermal property, arbitrary change of heat transfer area on both hot and cold sides, and long-distance heat transfer, heat pipes have been widely used. Pursuing high heat transfer efficiency and high stability has always been the basic goal of heat transfer research. As the core part of a heat pipe, the structure and morphology of the wick largely determine the heat and mass transfer performance of the heat pipe. When designing the wick, the contradiction between permeability and capillary pressure needs to be considered. A wick with good permeability requires a larger pore diameter to promote liquid flow, while a heat pipe with sufficient capillary pressure requires a smaller pore diameter. Therefore, a balance needs to be achieved between the two. To meet the requirements of high working conditions, people usually adopt a composite wick structure, combining two or more wick structures together to achieve a composite pore diameter wick and make full use of their respective advantages.

[0003] The existing composite pore diameter wick structure is random, which may result in gaps causing a large thermal resistance, or closed pores being blocked, reducing permeability, and restricting the application of this method in the field of heat pipe wick manufacturing. Content of the Utility Model

[0004] The purpose of the utility model is to overcome the deficiencies of the prior art, and provides a high-performance wick with micro-nano composite pores for a heat pipe and a heat pipe thereof, which has a regularly arranged composite pore structure and solves the problems in the above background technique.

[0005] The technical solution adopted by the utility model to solve its technical problems is: a high-performance wick with micro-nano composite pores for a heat pipe is provided, which is composed of an array arrangement of a plurality of matrix units. The matrix unit is provided with micron-sized pores and nano-sized pores; the matrix unit is a hollow cube, the micron-sized pores penetrate from the center of one face to the center of its opposite face, the nano-sized pores are distributed around the outer periphery of the micron-sized pores, the nano-sized pores extend in the direction from one face to the opposite face and are mutually communicated with the micron-sized pores; the micron-sized pores and nano-sized pores between adjacent matrix units are mutually communicated.

[0006] In a preferred embodiment of the utility model, the matrix units are arranged in an array along the straight lines where three mutually perpendicular edges are located respectively.

[0007] In a preferred embodiment of the utility model, the nano-sized pores are equally angularly distributed around the outer periphery of the micron-sized pores.

[0008] In a preferred embodiment of the present utility model, adjacent matrix units have micron-scale holes and nano-scale holes with the same positional distribution on their mating surfaces.

[0009] In a preferred embodiment of the present utility model, the micron-scale holes or nano-scale holes form a cross-shaped channel at the intersection of two through-holes.

[0010] In a preferred embodiment of the present utility model, the aperture of the micron-scale holes is 10 μm to 100 μm.

[0011] In a preferred embodiment of the present utility model, the aperture of the nano-scale holes is 10 nm to 100 nm.

[0012] In a preferred embodiment of the present utility model, the total thickness of the wick is 0.5 mm to 2 mm.

[0013] In a preferred embodiment of the present utility model, the material of the wick is stainless steel, copper, aluminum, nickel or nickel alloy.

[0014] The present utility model also provides a heat pipe, including a high-performance wick with micro-nano composite holes for a heat pipe as described above.

[0015] Compared with the background technology, this technical solution has the following advantages:

[0016] 1. The wick of this solution adopts the arrangement method of porous unit arrays, and the arrangement method of matrix units can be determined according to needs;

[0017] 2. The wick of this solution contains two functional structures, micron-scale hole and nano-scale hole structures. The liquid working medium is transported through the micron-scale holes to enhance permeability, and at the same time, the nano-scale holes around the micron-scale holes strengthen the capillary pumping force, making it more adaptable to high working condition requirements;

[0018] 3. The wick of this solution can manufacture matrix units containing micron-scale holes through 3D printing additive manufacturing method. After pretreatment of the matrix units, they are used as anodes for anodic electrolytic oxidation, and nano-scale holes are manufactured through subtractive manufacturing method, so as to obtain a wick with micro-nano composite pore diameters, without the pore uncertainty of traditional sintering methods, and has good industrial practicability;

[0019] 4. Applying the wick of this solution to a heat pipe helps to prepare a heat pipe device with extremely high thermal conductivity, good isothermal property, arbitrary change of heat transfer area on both hot and cold sides, and long-distance heat transfer. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 It is the overall structure diagram of the wick.

[0022] Figure 2 It is the structure diagram of the matrix unit.

[0023] Figure 3 It is the cross-sectional view of the matrix unit.

[0024] Among them, 1 - wick, 2 - matrix unit, 3 - micron-sized hole, 4 - nano-sized hole, 5 - cross-shaped channel. Specific embodiments

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0026] Embodiment

[0027] A high-performance wick 1 with micro-nano composite pores for a heat pipe is composed of a number of matrix units 2 arranged in an array along the straight lines of three mutually perpendicular edges. The wick 1 material in this embodiment is made of 316L stainless steel, and the overall dimensions are 60 mm in length, 20 mm in width, and 0.5 mm in thickness.

[0028] The matrix unit 2 is provided with micron-sized holes 3 and nano-sized holes 4. The aperture of the micron-sized holes 3 is 10 μm to 100 μm, and the aperture of the nano-sized holes 4 is 10 nm to 100 nm. The matrix unit 2 is a hollow cube. The micron-sized holes 3 penetrate from the center of one face to the center of its opposite face. The nano-sized holes 4 are distributed around the outer periphery of the micron-sized holes 3. The nano-sized holes 4 extend in the direction from one face to the opposite face and are in mutual communication with the micron-sized holes 3. The micron-sized holes 3 and nano-sized holes 4 between adjacent matrix units 2 are in mutual communication.

[0029] In this embodiment, the nanoscale pores 4 are distributed at equal angles around the outer periphery of the microscale pores 3. The adjacent matrix units 2 have microscale pores 3 and nanoscale pores 4 distributed at the same positions on their mating surfaces. The microscale pores 3 or the nanoscale pores 4 form a cross-shaped channel 5 at the intersection of the two through holes.

[0030] The wick 1 of this embodiment is manufactured by 3D printing additive manufacturing and anodic oxidation technologies, and the material is 316L stainless steel. The particle size range of this stainless steel powder is 15μm - 53μm, D10 is 21.8μm, D50 is 32.7μm, D90 is 48.8μm, and the fluidity (Hall flow rate) ≤ 18s / 50g. The specific steps are as follows:

[0031] The process of 3D printing additive and subtractive manufacturing of the 316L stainless steel micro-nano composite pore wick 1 is as follows:

[0032] Step 1. Modeling: Use commercial 3D modeling software such as solidworks to design the microscale pores 3 with a diameter of 50μm and the matrix unit 2 in the shape of a hollow cube. After determining that the outer shape of the wick 1 is a cuboid with a length of 60mm, a width of 20mm, and a thickness of 0.5mm, plan the arrangement route of the matrix unit 2. Through the array operation, the matrix unit 2 completely fills the macroscopic shape of the wick 1, and the array direction is the straight lines where the three mutually perpendicular edges of the matrix unit 2 are located respectively. Subsequently, import it into the Materialise Magics software for model repair and support generation, and then import the generated STL file into the 3D printing path scanning software for corresponding path planning file slicing processing, with each slice having a thickness of 50μm. Then, regard the sheet data with a certain thickness as two-dimensional plane data, use the path planning software to fill this data layer by layer, and transmit the set laser scanning path file into the 3D printer system. The galvanometer of the printer will scan according to this path;

[0033] Step 2. 3D printing:

[0034] Select the selective laser sintering (SLS) technology to prepare the micro-pore wick 1, with a processing power of 110W, a laser spot diameter of 0.01mm, a scanning pitch of 0.01mm, a scanning speed of 100mm / s, and a powder spreading thickness of 30μm. Print the porous matrix 103 layer by layer, and then clean, vacuum dry the wick 110, seal it, and store it in a dry environment for secondary processing.

[0035] Step 3. Anodic oxidation process flow design:

[0036] To prevent the impurities adsorbed by the matrix unit 2 of the liquid absorption core 1 from contaminating the electrolyte and affecting the electrolysis experiment, it is necessary to strictly design the anodizing process flow of the 3D printed liquid absorption core 1. First, the surface of the 3D printed liquid absorption core 1 is mechanically polished, and then it is ultrasonically cleaned with absolute ethanol and deionized water for 15 minutes each. Then, it is vacuum dried for 30 minutes. Next, the liquid absorption core 1 is placed in an electrolytic cell for oxidation for 20 - 60 minutes to remove the surface oxide layer and impurities. Then, it is ultrasonically cleaned with deionized water and absolute ethanol for 15 minutes each to wash the electrolyte on the surface of the liquid absorption core 1. Finally, it is vacuum dried for 30 minutes for standby.

[0037] Step 4. Anodizing:

[0038] Set up an anodizing processing platform, fix the dried 3D printed liquid absorption core 1 with a bracket, connect it to the positive electrode of an adjustable constant voltage DC power supply (0 - 60V) as the anode for electrolytic oxidation. Select a graphite sheet as the cathode electrode and fix it, connect it to the negative electrode of the power supply, with the same size as the liquid absorption core 1. The two electrodes are immersed in the electrolyte, and at the same time, tape is used to assist in fixing the two electrodes to prevent shaking during the experiment. The electrolyte is a 0.1mol / L KCL solution, the distance between the two electrodes is 50mm, and the electrolysis voltage is 20V. The electrolysis experiment is carried out in a beaker, and the beaker is placed in an ultrasonic incubator, which provides a stable heat preservation temperature of 10°C and provides vibration to accelerate the reaction rate. The temperature of the electrolyte is monitored by a thermometer fixed by a bracket throughout the process, and the oxidation time is set to 20 - 60 minutes. Through anodizing, nano-scale pores 4 with a certain regularity can be processed on the surface of the matrix unit 2.

[0039] A heat pipe prepared using the liquid absorption core 1 of this embodiment transports the liquid working medium through the micro-scale pores 3 to enhance permeability. At the same time, the nano-scale pores 4 around the micro-scale pores 3 strengthen the capillary suction force, making it more adaptable to high working conditions.

[0040] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A high-performance liquid-absorbing core with micro-nano composite pores for a heat pipe, characterized in that: The invention is composed of a plurality of matrix units arranged in an array, wherein the matrix units are provided with micrometer-scale holes and nanometer-scale holes; the matrix units are hollow cubes, wherein the micrometer-scale holes extend from the center of one face to the center of the opposite face, and the nanometer-scale holes are distributed around the periphery of the micrometer-scale holes, and the nanometer-scale holes extend in a direction facing the opposite face and are interconnected with the micrometer-scale holes; and the micrometer-scale holes and nanometer-scale holes of adjacent matrix units are interconnected.

2. A high-performance liquid-absorbing core with micro-nano composite pores for a heat pipe according to claim 1, characterized in that: The base units are arranged in an array along the straight lines where three mutually perpendicular edges are located.

3. The high-performance liquid-absorbing core with micro-nano composite pores for heat pipe according to claim 1, characterized in that: The nanoscale pores are distributed at equal angles around the periphery of the microscale pores.

4. The high-performance liquid-absorbing core with micro-nano composite pores for heat pipe according to claim 1, characterized in that: Adjacent base units have micrometer-scale pores and nanometer-scale pores distributed in the same position on their abutting surfaces.

5. The high-performance liquid-absorbing core with micro-nano composite pores for heat pipe according to claim 1, characterized in that: The micrometer-scale holes or nanometer-scale holes form a cross-shaped channel at the intersection of two through holes.

6. The high-performance liquid-absorbing core with micro-nano composite pores for heat pipe according to claim 1, characterized in that: The diameter of the micron-sized pores is 10 μm to 100 μm.

7. The high-performance liquid-absorbing core with micro-nano composite pores for heat pipe according to claim 1, characterized in that: The diameter of the nanoscale pores is 10 nm to 100 nm.

8. The high-performance liquid-absorbing core with micro-nano composite pores for heat pipe according to claim 1, characterized in that: The total thickness of the liquid-absorbing core is 0.5 mm to 2 mm.

9. The high-performance liquid-absorbing core with micro-nano composite pores for heat pipe according to claim 1, characterized in that: The material of the wick is stainless steel, copper, aluminum, nickel or nickel alloy.

10. A heat pipe, characterized in that: The invention comprises a high-performance liquid-absorbing core with micro-nano composite pores for a heat pipe as described in any one of claims 1 to 9.

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