Heat pipe and method of making same

Abstract

The application relates to a heat pipe and a preparation method thereof. The preparation method of the heat pipe comprises the following steps: S1, preparing a groove structure on the inner wall of a copper pipe; S2, covering the groove structure to prepare a super-hydrophobic acid-resistant layer, the super-hydrophobic acid-resistant layer starts from one end of the copper pipe and extends to a certain length inside; S3, forming a micro-nano size rough surface on the groove structure through SRB bacteria corrosion, the micro-nano size rough surface starts from the other end of the copper pipe and extends to the joint of the super-hydrophobic acid-resistant layer; and S4, preparing the heat pipe by taking the copper pipe section of the super-hydrophobic acid-resistant layer as a condensing section and taking the copper pipe section of the micro-nano size rough surface as an adiabatic section and an evaporating section. The preparation method of the heat pipe can improve the hydrophilic performance of the adiabatic section and the evaporating section of the heat pipe, accelerate the backflow speed of the liquid working medium, and further improve the heat transfer efficiency of the heat pipe by forming the micro-nano size rough surface on the groove structure through SRB bacteria corrosion.

Description

Technical Field

[0001] This invention relates to the field of heat pipe manufacturing technology, and in particular to a heat pipe and its manufacturing method. Background Technology

[0002] A heat pipe is a heat dissipation device that utilizes the phase change process of a medium evaporating at the hot end and condensing at the cold end to achieve rapid heat dissipation. The heat pipe is evacuated to a negative pressure state and filled with a suitable liquid working fluid; this liquid has a low boiling point and is easily volatile. The pipe wall is equipped with a wick composed of a capillary porous structure. One end of the heat pipe is the evaporation end, and the other end is the condensation end. When one end of the heat pipe is heated, the liquid in the capillary rapidly vaporizes. The vapor flows to the other end under the force of thermal diffusion and condenses at the condensation end, releasing heat. The liquid then flows back to the evaporation end along the porous material by capillary action. This cycle continues until the temperature at both ends of the heat pipe is equal (at which point vapor thermal diffusion stops).

[0003] Since the amount of liquid working fluid that can be filled into a heat pipe is limited, improving its heat dissipation capacity requires higher capillary performance of the capillary porous structure. This would enable rapid reflux of the liquid working fluid within the heat pipe, thereby improving its heat transfer efficiency and preventing the evaporator section from drying out under high heat power. However, current heat pipe fabrication often uses a single groove as the capillary structure for transporting the liquid working fluid, resulting in generally poor capillary performance and low heat transfer efficiency. Summary of the Invention

[0004] Therefore, the purpose of this invention is to provide a method for preparing a heat pipe, which enables rapid reflux of the liquid working fluid inside the heat pipe, thereby improving the heat transfer efficiency of the heat pipe.

[0005] The present invention provides a method for preparing a heat pipe, comprising the following steps:

[0006] S1: A groove structure is prepared on the inner wall of the copper tube;

[0007] S2: A superhydrophobic and acid-resistant layer is prepared by covering the trench structure. The superhydrophobic and acid-resistant layer starts from one end of the copper tube and extends to a certain length inside.

[0008] S3: A micro-nano-sized rough surface is formed by SRB bacteria corroding the trench structure. The micro-nano-sized rough surface starts from the other end of the copper tube and extends to contact the superhydrophobic acid-resistant layer.

[0009] S4: A heat pipe is prepared by using the copper tube segment with the superhydrophobic and acid-resistant layer as the condensation section and the copper tube segment with the micro-nano-sized rough surface as the insulation section and the evaporation section.

[0010] Further, step S3 includes:

[0011] The copper tube is placed vertically, with the end of the copper tube containing the superhydrophobic and acid-resistant layer facing upwards;

[0012] SRB culture medium with a carbon content of 15%-40% is uniformly sprayed onto the surface of the trench structure.

[0013] The copper tube is cultured in an anaerobic environment for 6-10 days, and the SRB bacteria corrode the groove structure to form a micro-nano-sized rough surface.

[0014] Furthermore, after the SRB bacteria corrode the trench structure to form a micro-nano-sized rough surface, the method further includes:

[0015] The copper tube is subjected to high-temperature sterilization treatment, wherein the heating temperature of the high-temperature sterilization treatment is greater than 120°C.

[0016] Further, step S2 includes:

[0017] A WO3 film is electroplated on the trench structure, the WO3 film starting from one end of the copper tube and extending to a certain length inside;

[0018] The portion of the copper tube coated with the WO3 film is immersed in a fluorosilane-ethanol solution with a mass ratio of 0.3% to 1.0% for hydrophobic treatment for 3 to 20 seconds.

[0019] Furthermore, step S4 specifically includes:

[0020] The length requirements of the condensation section, the insulation section, and the evaporation section are determined separately, and the two ends of the copper tube are cut according to the two length requirements.

[0021] After the copper tubes are cut, they are cleaned, dried, shrunk, welded and sealed, vacuumed, and injected with liquid to obtain a heat pipe.

[0022] Furthermore, a groove structure is prepared on the inner wall of the copper tube by broaching.

[0023] Furthermore, the cross-section of the trench structure perpendicular to the length of the copper tube can be rectangular, trapezoidal, or triangular.

[0024] Another object of the present invention is to provide a heat pipe, which is prepared according to any of the above-described preparation methods.

[0025] This invention provides a method for fabricating a heat pipe. A grooved structure is prepared on the inner wall of the heat pipe, and a superhydrophobic, acid-resistant layer is prepared on the grooved structure via electroplating. A micro-nano-sized rough surface is also prepared via SRB bacterial corrosion. The micro-nano-sized rough surface enhances the capillary capacity of the heat pipe's inner surface, achieving a hydrophilic effect. The superhydrophobic, acid-resistant layer section of the copper pipe is used as the condensation section, and the micro-nano-sized rough surface section of the copper pipe is used as the insulation and evaporation sections. The superhydrophobic properties of the condensation section help improve the condensation capacity of the liquid working fluid, while the hydrophilic properties of the insulation and evaporation sections help improve the reflux capacity of the liquid working fluid, thereby increasing the heat transfer efficiency of the heat pipe.

[0026] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0027] Figure 1 This is a schematic diagram illustrating the steps of a heat pipe fabrication method according to the present invention;

[0028] Figure 2 This is a cross-sectional schematic diagram of a copper tube trench structure for a heat pipe according to the present invention;

[0029] Figure 3 This is a cross-sectional schematic diagram of the micro-nano-scale roughened surface of a copper tube in a heat pipe according to the present invention;

[0030] Figure 4 This is a schematic diagram of the structure of a copper tube with a micro-nano-scale rough surface in a heat pipe according to the present invention;

[0031] Figure 5 This is a schematic diagram of the structure of a heat pipe according to the present invention.

[0032] Figure label:

[0033] 1. Tube body; 11. Groove structure; 12. Micro-nano-sized rough surface; 2. Inner cavity. Detailed Implementation

[0034] like Figure 1 As shown, the present invention provides a method for preparing a heat pipe, the method comprising the following steps:

[0035] S1: Create a groove structure on the inner wall of the copper tube.

[0036] First, a sufficiently long copper tube is obtained, and a groove structure 11 is prepared on the inner wall of the tube body 1 by drawing. The prepared groove structure 11 is as follows: Figure 2 As shown, when the heat pipe is dissipating heat, the liquid working fluid flows from the condensation section back to the evaporation section along the groove structure 11 under the capillary action of the groove structure 11. The cross-section of the groove structure 11 perpendicular to the length of the copper pipe can be rectangular, trapezoidal, or triangular, depending on the broach used for broaching.

[0037] S2: A superhydrophobic and acid-resistant layer is prepared by covering the trench structure. The superhydrophobic and acid-resistant layer starts from one end of the copper tube and extends to a certain length inside.

[0038] This application prepares an acid-resistant thin film by electroplating. Specifically, a copper tube is connected to the negative terminal of the power supply as the cathode of the electroplating tank, and the vertical part of the copper tube is immersed in the WO3 electroplating solution, so that the part of the copper tube immersed in the electroplating solution, including the end of the copper tube to a certain length, is electroplated with an acid-resistant WO3 thin film.

[0039] Optionally, an anti-plating agent is applied to the outer surface of the copper tube before electroplating, so that a WO3 film is electroplated only on the inner wall groove structure surface of the copper tube, and the anti-plating agent on the outer surface is cleaned off after electroplating.

[0040] Then, the portion of the copper tube coated with the WO3 film is immersed in a fluorosilane-ethanol solution with a mass ratio of 0.3% to 1.0% for hydrophobic treatment for 3 to 20 seconds, so that the inside of the copper tube has a superhydrophobic and acid-resistant layer.

[0041] S3: A micro-nano-sized rough surface is formed by SRB bacteria corroding the trench structure 11. The micro-nano-sized rough surface starts from the other end of the copper tube and extends to the superhydrophobic acid-resistant layer.

[0042] The specific steps include: placing the copper tube vertically with the end containing the superhydrophobic and acid-resistant layer facing upwards; inserting a nozzle with multiple nozzles arranged circumferentially into the copper tube from bottom to top, so that the nozzle simultaneously and uniformly sprays SRB culture solution containing 15%-40% carbon onto the surface of the groove structure 11 of the copper tube, and the SRB culture solution can be sprayed onto all surfaces of the groove structure 11 not covered by the superhydrophobic and acid-resistant layer film until it comes into contact with the surface of the superhydrophobic and acid-resistant layer. Moreover, since the micro-nano-sized rough surface 12 is mainly obtained by acid corrosion of the copper surface by SRB bacteria, even if the SRB culture solution is accidentally sprayed onto the surface of the superhydrophobic and acid-resistant layer, it will not affect the hydrophobic properties of the superhydrophobic and acid-resistant layer.

[0043] The copper tubes sprayed with SRB culture medium were placed in an anaerobic environment for 6-10 days. The SRB bacteria corroded the groove structure 11, forming a micro-nano-sized rough surface 12. Figure 3 and Figure 4 As shown, the micro-nano-sized rough surface 12 treated with SRB bacteria has a finer porous surface structure than that in the prior art, thus improving hydrophilicity.

[0044] S4: A heat pipe is prepared by using the copper tube segment with the superhydrophobic and acid-resistant layer as the condensation section and the copper tube segment with the micro-nano-sized rough surface as the insulation section and the evaporation section.

[0045] After preparing a superhydrophobic acid-resistant layer surface and a micro-nano-sized rough surface 12 on the surface of the groove structure 11 on the inner wall of the copper tube, the superhydrophobic acid-resistant layer surface inside the copper tube has excellent superhydrophobic properties, and the micro-nano-sized rough surface 12 inside the copper tube has excellent hydrophilic properties. The copper tube section with the superhydrophobic acid-resistant layer is used as the condensation section, and the copper tube section with the micro-nano-sized rough surface 12 is used as the insulation section and the evaporation section to prepare a heat pipe.

[0046] The fabrication of a heat pipe includes: determining the length of the condensing section and the total length of the adiabatic and evaporating sections based on the heat dissipation requirements of the heating element, and then cutting the copper tube at both ends according to these two length measurements. After cleaning and drying the copper tube, the condensing section ends are screwed together and welded to seal them. The vacuuming and liquid injection processes are then completed, ultimately resulting in the heat pipe as shown. Figure 5 As shown, the heat pipe body 1 includes a condensation section, an insulation section and an evaporation section. The inner cavity 2 formed inside the heat pipe body 1 is in a vacuum or negative pressure state and is filled with a liquid working fluid with a low boiling point.

[0047] After the heat pipe is fabricated, it needs to be sterilized at high temperature to prevent excessive corrosion by SRB bacteria, which could affect the heat pipe's performance. Preferably, in this embodiment, the copper pipe is not subjected to separate high-temperature heating. During the fabrication of the heat pipe, a series of performance tests are conducted. Among these tests, the high-low temperature cycling test involves temperatures exceeding 120°C, which can completely eliminate SRB colonies and prevent further corrosion.

[0048] This invention provides a method for fabricating a heat pipe. A grooved structure is prepared on the inner wall of the heat pipe, and a superhydrophobic, acid-resistant layer is prepared on the grooved structure via electroplating. A micro-nano-sized rough surface is also prepared via SRB bacterial corrosion. The micro-nano-sized rough surface enhances the capillary capacity of the heat pipe's inner surface, accelerating the liquid's spreading speed and achieving a hydrophilic effect. The superhydrophobic, acid-resistant layer surface section of the copper pipe serves as the condensation section, while the micro-nano-sized rough surface section of the copper pipe serves as the insulation and evaporation sections. This design allows the superhydrophobic properties of the condensation section to improve the condensation capacity of the liquid working fluid, while the hydrophilic properties of the insulation and evaporation sections enhance the reflux capacity of the liquid working fluid, thereby improving the heat transfer efficiency of the heat pipe.

[0049] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for manufacturing a heat pipe, characterized in that, Includes the following steps: S1: A groove structure is prepared on the inner wall of the copper tube; S2: A superhydrophobic and acid-resistant layer is prepared by covering the trench structure. The superhydrophobic and acid-resistant layer starts from one end of the copper tube and extends to a certain length inside. S3: Place the copper tube vertically, with the end of the copper tube containing the superhydrophobic and acid-resistant layer facing upwards; uniformly spray SRB culture medium with a carbon content of 15%-40% onto the surface of the trench structure; culture the copper tube in an anaerobic environment for 6-10 days, during which the SRB bacteria corrode the trench structure to form a micro-nano-sized rough surface, which begins at the other end of the copper tube and extends to contact the superhydrophobic and acid-resistant layer; S4: A heat pipe is prepared by using the copper tube segment with the superhydrophobic and acid-resistant layer as the condensation section and the copper tube segment with the micro-nano-sized rough surface as the insulation section and the evaporation section.

2. The method for preparing a heat pipe according to claim 1, characterized in that, After the SRB bacteria corrode the trench structure to form a micro-nano-sized rough surface, the method further includes: The copper tube is subjected to high-temperature sterilization treatment, wherein the heating temperature of the high-temperature sterilization treatment is greater than 120°C.

3. The method for preparing a heat pipe according to claim 2, characterized in that, Step S2 includes: A WO3 film is electroplated on the trench structure, the WO3 film starting from one end of the copper tube and extending to a certain length inside; The portion of the copper tube coated with the WO3 film is immersed in a fluorosilane-ethanol solution with a mass ratio of 0.3% to 1.0% for hydrophobic treatment for 3 to 20 seconds.

4. The method for preparing a heat pipe according to claim 2, characterized in that, Step S4 specifically includes: The length requirements of the condensation section, the insulation section, and the evaporation section are determined separately, and the two ends of the copper tube are cut according to the two length requirements. After the copper tubes are cut, they are cleaned, dried, shrunk, welded and sealed, vacuumed, and injected with liquid to obtain a heat pipe.

5. The method for preparing a heat pipe according to claim 4, characterized in that: Groove structures are created on the inner wall of copper tubes by broaching.

6. The method for preparing a heat pipe according to claim 5, characterized in that: The cross-section of the trench structure perpendicular to the length of the copper tube is rectangular, trapezoidal, or triangular.

7. A heat pipe, characterized in that: It is prepared by any one of the preparation methods in claims 1-6.

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