Heat pipe with micro-nano structure

Abstract

The utility model relates to the technical field of heat pipe heat exchangers, in particular to a heat pipe with a micro-nano structure, which comprises a heat pipe body, a sintering powder layer is covered on the surface of the inner wall of the heat pipe body, the sintering powder layer is formed by mixing large-particle-size heat conduction powder and small-particle-size heat conduction powder, and a gap is reserved between the sintering powder layer and the inner wall of the heat pipe body. Nanowires and nanosheets are arranged on the inner wall of the heat pipe body, the surfaces of the large-particle-size heat conduction powder and the surfaces of the small-particle-size heat conduction powder, and the formed nanowires and nanosheets can remarkably improve the surface wettability, liquid fluidity, bubble removal capacity, condensation performance and the like of the inner wall, so that the heat exchange efficiency of the heat exchanger is effectively improved. The micro-nano structure is introduced into the inner wall of the heat pipe, so that the capacity of capturing tiny liquid drops in air and the capacity of transporting water collecting liquid drops are remarkably improved, the wettability and the heat exchange efficiency of liquid are remarkably improved, the evaporation and condensation processes of working media in the heat pipe are optimized, and therefore the stability and the heat exchange performance of the heat pipe are improved.

Description

Technical Field

[0001] This utility model relates to the field of heat pipe heat exchanger technology, and more specifically, to a heat pipe with a micro-nano structure. Background Technology

[0002] A heat pipe heat exchanger is a device that utilizes the highly efficient thermal conductivity of heat pipes for heat exchange. It achieves heat transfer by having the working fluid (such as a liquid) inside the heat pipe absorb heat and evaporate in the evaporation section, then release heat and condense into a liquid in the condensation section. Through heat pipe heat exchangers, heat can be efficiently transferred from one object or fluid to another, thus meeting various thermal management needs.

[0003] Heat pipe heat exchangers, with their high thermal conductivity and simple structure, are widely used in electronic device heat dissipation, refrigeration, air conditioning, and heat recovery. However, the inner wall of traditional heat pipes typically has a smooth surface, which leads to relatively low efficiency in the evaporation and condensation processes of the working fluid inside the heat pipe, especially at high heat flux densities, where heat exchange efficiency drops significantly. Furthermore, the poor wettability of the liquid on the inner wall of the heat pipe can cause liquid stagnation and bubble blockage during operation, thus affecting the stability of the heat pipe. Therefore, improving the inner wall structure of the heat pipe to enhance liquid wettability and heat exchange efficiency has become a key issue in improving the heat exchange performance of heat pipes. Utility Model Content

[0004] To address the shortcomings of existing heat pipes, this invention provides a heat pipe with a micro-nano structure. By introducing micro-nano structures into the inner wall of the heat pipe, the wettability of the liquid is improved, and the evaporation and condensation process of the working fluid inside the heat pipe is optimized, thereby significantly improving the heat exchange efficiency and the stability of the heat pipe.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] A heat pipe with a micro / nano structure includes a heat pipe body. The inner wall surface of the heat pipe body is coated with a sintered powder layer, which is composed of a mixture of large-particle-size and small-particle-size thermally conductive powders. A gap exists between the sintered powder layer and the inner wall of the heat pipe body. Nanowires and / or nanosheets are formed on the inner wall of the heat pipe body, the surfaces of the large-particle-size and small-particle-size thermally conductive powders. During the use of the heat pipe, the formed nanowires and nanosheets can significantly improve the surface wettability of the inner wall, liquid flowability, bubble removal ability, and condensation performance, thereby effectively improving the heat exchanger's heat exchange efficiency.

[0007] Furthermore, the large-particle-size thermal conductive powder is large-particle-size copper powder; the small-particle-size thermal conductive powder is small-particle-size copper powder.

[0008] Furthermore, the large-particle-size thermal conductive powder and the small-particle-size thermal conductive powder are attached to the inner wall of the heat pipe body by sintering. The heat pipe body is filled with condensate. One end of the heat pipe body is a conical closed structure, and the other end is sealed after being filled with condensate.

[0009] Furthermore, the nanowires and nanosheets on the inner wall of the heat pipe, the surface of the large-particle-size thermal conductive powder, and the surface of the small-particle-size thermal conductive powder are formed by corrosion treatment with an alkaline corrosion solution.

[0010] Furthermore, the nanowires typically have a radius of 100 nm-250 nm and a length of approximately 5 μm-10 μm.

[0011] Furthermore, the typical size of the nanosheet is between 10 nm and 50 nm in thickness, and 400 nm and 600 nm in length and width, generally about 500 nm × 500 nm.

[0012] Furthermore, the heat pipe body material can be metal, ceramic, carbon-based material or their composite material, and the material has high thermal conductivity and excellent mechanical properties to ensure the heat pipe's efficient heat transfer capability and long-term stability during use.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] This invention significantly improves the heat pipe's ability to capture tiny droplets from the air and transport water droplets by introducing micro- and nano-structures into the inner wall. This significantly enhances the wettability and heat transfer efficiency of the liquid, and optimizes the evaporation and condensation processes of the working fluid within the heat pipe, thereby improving the heat pipe's stability and heat transfer performance. Specifically, the introduction of micro- and nano-structures effectively enhances the efficiency of droplet condensation and transport, resulting in superior performance in heat transfer, droplet capture, and transport capabilities.

[0015] Furthermore, this invention can be manufactured using a low-cost production process, enabling large-scale production at a lower cost, which further enhances its competitiveness in industrial applications. It has broad application prospects and huge market potential in fields such as energy conservation and environmental protection, droplet capture and transportation. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0017] Figure 2 This is a cross-sectional view of the present invention.

[0018] Figure 3 This is a schematic diagram of the sintered powder layer in this utility model.

[0019] Figure 4 This is a schematic diagram of the nanowire structure in this invention.

[0020] Figure 5 This is a schematic diagram of the structure of the nanosheet in this utility model.

[0021] Figure 6 This is a schematic diagram of the high-concentration corrosion process in Embodiment 1 of this utility model.

[0022] Figure 7 This is a schematic diagram of the low-concentration corrosion process in Embodiment 2 of this utility model.

[0023] In the figure: 1. Heat pipe body; 2. Sintered powder layer; 21. Large particle size thermal conductive powder; 22. Small particle size thermal conductive powder; 3. Nanowire; 4. Nanosheet. Detailed Implementation

[0024] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0025] Example 1:

[0026] like Figures 1 to 5 As shown, a heat pipe with a micro / nano structure includes a heat pipe body 1. The inner wall surface of the heat pipe body is coated with a sintered powder layer 2, which is composed of a mixture of large-particle-size thermally conductive powder 21 and small-particle-size thermally conductive powder 22. There is a gap between the sintered powder layer 2 and the inner wall of the heat pipe body 1. Nanowires 3 are provided on the inner wall of the heat pipe body 1, the surface of the large-particle-size thermally conductive powder 21, and the surface of the small-particle-size thermally conductive powder 22. During the use of the heat pipe, the formed nanowires 3 can significantly improve the surface wettability of the inner wall, liquid flowability, bubble removal ability, and condensation performance, thereby effectively improving the heat exchange efficiency of the heat exchanger.

[0027] In this embodiment, the large-particle-size thermal conductive powder 21 is large-particle-size copper powder, and the small-particle-size thermal conductive powder 22 is small-particle-size copper powder. The material of the heat pipe body 1 can be metal, ceramic, carbon-based material or their composite material, and the material has high thermal conductivity and excellent mechanical properties to ensure the efficient heat transfer capability and long-term stability of the heat pipe during use.

[0028] It should be noted that the large-diameter and small-diameter copper powders used serve two purposes: firstly, to increase the contact area; and secondly, to act as a supporting structure to ensure a certain flow flux of water and air.

[0029] In this embodiment, the nanowires 3 on the inner wall of the heat pipe body 1, the surface of the large-particle-size thermal conductive powder 21, and the surface of the small-particle-size thermal conductive powder 22 are formed by corrosion treatment with an alkaline corrosion solution. The nanoscale microstructure generated by the corrosion solution can not only enhance the hydrophilicity inside the heat pipe, but also provide a core for the boiling of superheated liquid and the condensation of supercooled steam, thereby expanding the boiling temperature range and accelerating the condensation rate, and further improving the heat exchange effect.

[0030] Preferably, the large-particle-size thermal conductive powder 21 and the small-particle-size thermal conductive powder 22 are attached to the inner wall of the heat pipe body 1 by sintering. The heat pipe body 1 is filled with condensate. One end of the heat pipe body 1 is a conical closed structure, and the other end is sealed after being filled with condensate.

[0031] The processing technology in this embodiment is as follows: Figure 6 As shown, the corrosion solution used is a high-concentration corrosion solution.

[0032] It should be noted that the main components of the high-concentration corrosive solution include sodium hydroxide, ammonium persulfate, and deionized water, with the mass ratio of sodium hydroxide to ammonium persulfate ranging from 1.0 to 2.5, and the corrosion time ranging from 2 to 10 minutes.

[0033] like Figure 6 Large-diameter copper powder and small-diameter copper powder are fixed on the inner wall surface of the heat pipe body 1 through a high-temperature sintering process to form a sintered powder layer 2. A 20% sodium hydroxide aqueous solution and a 5% ammonium persulfate solution are prepared, mixed, and allowed to stand for 1 hour to allow the solution to cool down. After cooling to room temperature, a high-concentration corrosion solution is injected into the heat pipe for corrosion treatment, with a corrosion time of 2 to 10 minutes.

[0034] Controlling the corrosion time is crucial: if the corrosion time is too short, the amount of copper hydroxide nanowires 3 formed will be insufficient; if the corrosion time is too long, the copper hydroxide nanowires 3 may cross-link, causing blockage of the gaps between the copper powder particles, thus affecting the flow rate of the liquid. After the corrosion process is complete, the corrosion solution must be removed, and the heat pipe must be thoroughly rinsed with clean water to remove any residual solution.

[0035] After cleaning, condensate is injected into the heat pipe body 1 and the pipe is sealed, after which the heat pipe is ready for use. This method can effectively improve the heat transfer performance of the heat pipe and enhance its application effect in high-efficiency thermal management.

[0036] It should be noted that the nanostructure formed by the high-concentration corrosive solution is copper hydroxide nanowire 3, and the typical size of this nanowire 3 is a radius of 100nm-250nm and a length of about 5μm-10μm.

[0037] Example 2:

[0038] The features that are the same as those in Embodiment 1 will not be repeated here. The difference between this embodiment and Embodiment 1 is that in this embodiment, nanosheets 4 are provided on the inner wall of the heat pipe body 1, the surface of the large-particle-diameter thermal conductive powder 21 and the small-particle-diameter thermal conductive powder 22. The technical effect and working principle of the nanosheets 4 are the same as those of the nanowires 3 in Embodiment 1.

[0039] It should be noted that in this embodiment, the corrosion solution used is a low-concentration corrosion solution, which can be used directly as a condensate. The main components of the low-concentration corrosion solution include sodium hydroxide, sodium persulfate, and deionized water, wherein the mass ratio of sodium hydroxide to sodium persulfate ranges from 1.0 to 2.5, and the mass of deionized water accounts for 99% to 99.9% of the solution; the corrosion time is 12 to 24 hours.

[0040] It should be noted that the nanostructure formed by the low-concentration corrosion solution is copper hydroxide nanosheet 4, and the typical size of the nanosheet 4 is between 10 nm and 50 nm in thickness and approximately 500 nm × 500 nm in length and width.

[0041] The processing technology in this embodiment is as follows: Figure 7 As shown, large-diameter copper powder and small-diameter copper powder are fixed on the inner wall surface of the heat pipe body 1 through a high-temperature sintering process to form a sintered powder layer 2. A 1% sodium hydroxide aqueous solution and a 0.25% ammonium persulfate solution are prepared, mixed, and allowed to stand for 1 hour to allow the solution to cool down. This low-concentration corrosion solution is then injected into the inner wall of the heat pipe body 1 as a condensate, and the pipe is then sealed.

[0042] After sealing, the heat pipe body 1 is placed in a shaker and shaken continuously for 24 hours. During this process, a large number of copper hydroxide nanosheets 4 will stably form inside the heat pipe body 1, thereby effectively improving the hydrophilicity of the inner wall of the heat pipe and the water transport speed. After completing the above operations, the heat pipe can be put into use. This method can improve the heat dissipation performance of the heat pipe under high-temperature sealing conditions and enhance its application effect in thermal management systems.

[0043] In other embodiments, it is also possible to first etch out nanowires 3, and then continue to etch out nanosheets 4 at the bottom of the heat pipe, with nanowires 3 and nanosheets 4 existing on the same heat pipe at the same time.

[0044] In the above embodiments, during use, the hydrophilic micro / nanostructure formed by nanowires 3 and nanosheets 4 can form a thin water film on the heat exchanger surface, promoting rapid heat transfer. When the liquid comes into contact with the surface, the hydrophilic surface enhances the wettability of the liquid, thereby improving the liquid's fluidity, reducing bubble formation, and improving heat exchange efficiency. During evaporation or condensation, the hydrophilicity of nanowires 3 and nanosheets 4 can accelerate the evaporation and condensation rates of the liquid, improving overall heat exchange performance. The hydrophilic micro / nanostructure helps the liquid form a more uniform film on the surface, resulting in better wettability of the liquid on the heat exchanger surface, reducing local accumulation or drying of the liquid, and optimizing the liquid flow path. This not only helps improve heat exchange efficiency but also prevents local overheating and undercooling caused by poor liquid flow, improving the stability and service life of the heat exchanger. During condensation, the hydrophilic micro / nanostructure formed by nanowires 3 and nanosheets 4 can effectively promote the rapid sliding of condensate droplets along the surface, reducing the time droplets remain on the surface. This accelerates the condensation process, improves the efficiency of heat release during condensation, and thus enhances the overall performance of the heat exchanger. Compared to traditional surfaces, hydrophilic surfaces can reduce droplet buildup, decrease thermal resistance, and improve heat exchange efficiency.

[0045] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating this utility model, and are not intended to limit the implementation of this utility model. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. Any obvious variations or modifications derived from the technical solutions of this utility model are still within the protection scope of this utility model.

Claims

1. A heat pipe with micro-nano structure, characterized in that: The heat pipe body (1) is coated with a sintered powder layer (2) on the inner wall surface, the sintered powder layer (2) is composed of large-particle-size heat-conducting powder (21) and small-particle-size heat-conducting powder (22), there is a gap between the sintered powder layer (2) and the inner wall of the heat pipe body (1), and the inner wall of the heat pipe body (1), the large-particle-size heat-conducting powder (21) and the small-particle-size heat-conducting powder (22) are all provided with nanowires (3) and / or nanosheets (4).

2. The heat pipe with micro-nano structure according to claim 1, characterized in that: The large-particle-size heat-conducting powder (21) is large-particle-size copper powder.

3. The heat pipe with micro-nano structure according to claim 2, characterized in that: The small-particle-size heat-conducting powder (22) is small-particle-size copper powder.

4. The heat pipe with micro-nano structure according to claim 3, characterized in that: The large-particle-size heat-conducting powder (21) and the small-particle-size heat-conducting powder (22) are attached to the inner wall of the heat pipe body (1) by sintering, the heat pipe body (1) is filled with condensate, one end of the heat pipe body (1) is a conical closed structure, and the other end is sealed after being filled with condensate.

5. The heat pipe with micro-nano structure according to claim 1, characterized in that: The nanowires (3) and nanosheets (4) on the surface of the inner wall of the heat pipe body (1), the large-particle-size heat-conducting powder (21) and the small-particle-size heat-conducting powder (22) are formed by alkaline etching solution etching treatment.

6. The heat pipe with micro-nano structure according to claim 1, characterized in that: The radius of the nanowires (3) is 100-250 nm, and the length is 5-10 microns.

7. The heat pipe with micro-nano structure according to claim 1, characterized in that: The thickness of the nanosheets (4) is 10-50 nm, and the length and width are both 400-600 nm. 8.The heat pipe with micro-nano structure according to claim 1, wherein: The material of the heat pipe body (1) is metal, ceramic or carbon-based material.

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