Corrosion-resistant sodium heat pipe, heat transfer device and manufacturing method thereof

Abstract

This application provides a corrosion-resistant sodium heat pipe, a heat transfer device, and a method for manufacturing the same. The corrosion-resistant sodium heat pipe includes: a tube body with a cavity containing a sodium working fluid; a cap sealed to the end of the tube body; and a wick arranged within the cavity of the tube body. The tube body and cap are made of ceramic material. The wick comprises a ceramic support and carbon nanotubes. The ceramic support has a return flow channel inside, and the carbon nanotubes cover the surface of the ceramic support forming the return flow channel, providing capillary pressure for the flow of the sodium working fluid. This invention ensures that all structural materials in the sodium heat pipe that come into contact with the sodium working fluid have good chemical compatibility with sodium, eliminating capillary degradation and tube body corrosion caused by wick dissolution at the source, thus achieving long-term stable service of the sodium heat pipe.

Description

Technical Field

[0001] This application relates to the field of heat transfer technology, specifically to a corrosion-resistant sodium heat pipe, a heat transfer device, and a method for manufacturing the same. Background Technology

[0002] Sodium heat pipes are highly efficient heat transfer elements using sodium as the working medium. They utilize a phase change cycle where the sodium working medium absorbs heat and vaporizes in the evaporation section and releases heat and condenses in the condensation section to achieve heat transfer. They offer advantages such as high thermal conductivity, excellent temperature uniformity, and the ability to be manufactured in various shapes, making them valuable for high-temperature heat transfer applications in energy, chemical, and other fields. The wick, as the functional structure driving the condensate recirculation, directly determines the heat transfer capacity and long-term service life of the sodium heat pipe through the stability of its capillary performance.

[0003] Generally, sodium heat pipes use a porous nickel-based metal wire mesh wick and a stainless steel or other metal tube body. This design has the following technical drawbacks: the liquid flow resistance of the nickel-based metal wire mesh wick is affected by the tightness of the wire mesh winding; gaps between the mesh layers result in high thermal resistance, potentially leading to excessive reflux resistance during condensate return. Furthermore, nickel in the nickel-based metal wire precipitates in the working medium, sodium, causing wire mesh corrosion and pore size damage. These factors can prevent condensate from properly returning to the evaporation section, affecting the normal operation of the sodium heat pipe. Additionally, the high temperature during heat pipe operation, combined with the presence of carbon and oxygen dissolved in the sodium solution, can cause a chemical reaction between the stainless steel outer shell and the sodium solution, leading to corrosion and a reduction in the sodium working fluid.

[0004] Based on this, this application provides a sodium heat pipe, a heat transfer device, and a method for manufacturing the same, in order to solve one or more of the aforementioned technical problems. Summary of the Invention

[0005] The first aspect of this application aims to provide a corrosion-resistant sodium heat pipe.

[0006] The second objective of this application is to provide a heat transfer device.

[0007] The objective of the third aspect of this application is to provide a method for manufacturing a corrosion-resistant sodium heat pipe.

[0008] According to a first aspect of this application, a corrosion-resistant sodium heat pipe includes: a tube body having a cavity inside the tube body, the cavity containing a sodium working fluid; a cap body sealingly connected to an end of the tube body; and a wicking core disposed within the cavity; wherein the tube body and the cap body are made of ceramic material; the wicking core includes a ceramic support and carbon nanotubes, the ceramic support having a return flow channel inside, the carbon nanotubes covering the surface of the ceramic support forming the return flow channel, and the carbon nanotubes providing capillary pressure for the flow of the sodium working fluid.

[0009] The sodium heat pipe provided in this application uses ceramic materials for both the tube body and the cap, which reduces corrosion problems caused by chemical reactions between the metal outer shell (such as stainless steel) and the sodium working fluid. The wick uses a composite structure of a ceramic support and carbon nanotubes. Carbon nanotubes, as an allotrope of carbon, have good chemical compatibility with sodium working fluid. Compared with traditional nickel-based metal wire wicks, this avoids the problem of nickel precipitation in the sodium solution causing wire corrosion and pore size damage. By incorporating a return flow channel inside the ceramic support, a clear return path is provided for the condensate, enhancing the condensate return capacity and ensuring the long-term stable operation of the sodium heat pipe. Compared with traditional metal wire mesh wicks, this avoids problems such as excessive return resistance due to gaps between mesh layers and fluctuations in return resistance due to unstable winding tightness.

[0010] In some embodiments, the return flow channel includes a leaf vein-shaped flow channel.

[0011] In some embodiments, the return flow channel includes a Tesla valve-shaped flow channel.

[0012] In some embodiments, the ceramic material used for the tube body and the cover body includes at least one of silicon carbide ceramic, silicon nitride ceramic, and alumina ceramic.

[0013] In some embodiments, the ceramic support is made of silicon carbide and / or silicon nitride.

[0014] The heat transfer device according to the second aspect of this application includes a sodium heat pipe as described in the first aspect, the sodium heat pipe being used to transfer heat between a heat source and a cold source.

[0015] The method for manufacturing a corrosion-resistant sodium heat pipe according to the third aspect of this application is used to manufacture a sodium heat pipe as described in the first aspect, the method comprising: The tube body and the cap body are provided, both made of ceramic material. The liquid-absorbing core is provided, the liquid-absorbing core comprising the ceramic support and the carbon nanotubes, and the liquid-absorbing core is provided by: processing the return flow channel inside the ceramic support; and covering the surface of the ceramic support forming the return flow channel with the carbon nanotubes. The suction core is arranged inside the cavity of the tube body; The cover is sealed to the tube, and sodium working fluid is injected into the cavity of the tube and then sealed.

[0016] In some embodiments, the provision of the liquid-absorbing core further includes manufacturing the carbon nanotubes using chemical vapor deposition and sintering the carbon nanotubes onto the surface of the ceramic support to form the return flow channel using a spark plasma process.

[0017] In some embodiments, providing the tube and cap made of ceramic material includes: mixing and molding ceramic raw materials, and then sintering them at high temperature under an inert atmosphere or vacuum.

[0018] In some embodiments, the process of injecting sodium working fluid into the cavity of the tube and sealing it includes: Sodium working fluid is injected into the cavity of the tube through the injection hole on the cover, and the injection volume of sodium working fluid is 50% to 150% of the saturated absorption capacity of the absorbent core. After freezing below the condensation temperature of liquid sodium, the gas is degassed and the injection hole is sealed. Attached Figure Description

[0019] The above and other features, properties, and advantages of this application will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always denote the same features. It should be noted that these drawings are merely illustrative and are not drawn to scale, and should not be construed as limiting the scope of protection actually claimed by this application, wherein: Figure 1 A schematic front cross-sectional view of a sodium heat pipe (with a leaf vein-shaped reflux channel) of one embodiment is shown.

[0020] Figure 2 schematically shown Figure 1 The image shows a side cross-sectional view of a sodium heat pipe.

[0021] Figure 3 A schematic front cross-sectional view of a sodium heat pipe (using a Tesla valve-shaped flow channel) of one embodiment is shown.

[0022] Figure 4 schematically shown Figure 3 The image shows a side cross-sectional view of a sodium heat pipe.

[0023] Figure 5 A schematic flowchart illustrating a method for manufacturing a sodium heat pipe according to one embodiment is shown.

[0024] Explanation of reference numerals in the attached figures: 1. Sodium heat pipe; 10. Pipe body; 20. Cover; 21. Filling hole; 30. Liquid suction core. Detailed Implementation

[0025] Reference will now be made in detail to various embodiments of this application, examples of which are shown in the accompanying drawings and described below. Although this application will be described in conjunction with exemplary embodiments, it should be understood that this application is not intended to be limited to those exemplary embodiments. Rather, this application is intended to cover not only these exemplary embodiments, but also various alternatives, modifications, equivalents, and other embodiments that may be included within the spirit and scope of this application as defined by the appended claims.

[0026] This application uses specific terms to describe embodiments of the application. For example, "an embodiment" and / or "one embodiment" refers to a particular feature, structure, or characteristic associated with at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment" or "one embodiment" mentioned twice or more in different locations in this application does not necessarily refer to the same embodiment. Furthermore, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0027] In this application, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying positional relationships or order of importance.

[0028] In the following description, the orientation or positional relationship indicated by terms such as "upper," "lower," "inner," "outer," "front," "back," or other directional terms is based on the orientation or positional relationship shown in the accompanying drawings and is only for the convenience of describing this application and simplifying the description, and is not intended to indicate or imply that the device or component referred to must have a specific orientation, be constructed and / or be implemented in a specific orientation, and therefore should not be construed as a limitation of this application.

[0029] In the following description, unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," "fixing," "contact," etc., should be interpreted broadly; for example, they can refer to fixed connections or movable connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in the embodiments of this application according to the specific circumstances.

[0030] This application uses flowcharts to illustrate the operations performed according to embodiments of this application. It should be understood that, depending on the actual situation, the steps shown in the diagrams are not necessarily performed sequentially, and other operations may be added to these processes, or one or more steps may be removed from these processes.

[0031] It is understood that the sodium heat pipe, heat transfer device and manufacturing method provided in this application can be applied to scenarios in the fields of energy, chemical industry and other technologies that require high-temperature heat transfer, and are not limited thereto.

[0032] The wick provides capillary pressure for the condensate in the sodium heat pipe, driving its reflux. Carbon nanotubes, an allotrope of diamond and graphite, two common carbon allotropes, possess excellent corrosion resistance and do not react with other structures in the sodium heat pipe, extending the wick's lifespan. Carbon nanotubes exhibit strong capillary action and a high surface area, effectively absorbing and transferring liquids. The wick 30, with its flow channel structure, alleviates the problem of sodium condensate reflux blockage.

[0033] like Figures 1 to 4 As shown, this application provides a corrosion-resistant sodium heat pipe 1, which includes: a pipe body 10, a cap 20, and a liquid-absorbing core 30. A cavity is formed within the pipe body 10, and the cavity is filled with sodium working fluid. The cap 20 is sealed to both ends of the pipe body 10. The liquid-absorbing core 30 is disposed within the cavity of the pipe body 10.

[0034] The tube body 10 and the cover body 20 are made of ceramic materials, such as silicon carbide ceramics, silicon nitride ceramics and alumina ceramics. These ceramic materials have high hardness, high melting point, excellent high temperature resistance and chemical stability (corrosion resistance). They can maintain stable performance in the high temperature and corrosive environment of sodium heat pipes, and have good thermal conductivity and mechanical properties.

[0035] The wick 30 comprises a ceramic support and carbon nanotubes. The ceramic support has an internal reflux channel, and the carbon nanotubes cover the surface of the ceramic support forming the reflux channel. The carbon nanotubes provide capillary pressure for the flow of the sodium working fluid. As an allotrope of carbon, carbon nanotubes have good chemical compatibility with sodium working fluid. Compared to traditional nickel-based metal wire wicks, they avoid the problems of nickel precipitation in the sodium solution causing wire corrosion and pore size damage. Furthermore, they possess strong capillary action and a high surface area, effectively absorbing and transferring liquid, making them excellent as wicks in sodium heat pipes. The reflux channel inside the ceramic support provides a clear reflux path for the condensate, enhancing condensate reflux capacity and ensuring long-term stable operation of the sodium heat pipe 1. Compared to traditional metal wire mesh wicks, this avoids problems such as excessive reflux resistance due to gaps between mesh layers and fluctuations in reflux resistance due to unstable winding tightness.

[0036] Preferably, the outer wall of the wick 30 is tightly abutted against the inner wall of the tube body 10 to reduce the contact thermal resistance between the wick 30 and the tube body 10, improve the radial heat transfer path from the tube body 10 to the wick 30, and enable the heat from the evaporation section to be transferred more efficiently to the sodium working fluid inside the wick 30, thereby improving the overall heat transfer efficiency of the sodium heat pipe. Simultaneously, the tight abutment between the wick 30 and the inner wall of the tube body 10 also provides radial support for the wick 30, improving structural stability. A through-hole 21 is also provided on one of the caps 20 for injecting sodium working fluid into the cavity of the tube body 10.

[0037] like Figure 1 As shown, in some embodiments, the return flow channel includes a vein-like flow channel. The vein-like return flow channel described herein generally exhibits a herringbone / fishbone pattern structure, with alternating branching along the axial direction, similar to the vein network of a plant leaf. Employing a vein-like return flow channel, biomimetic to plant leaf veins, effectively increases the surface area of ​​the flow channel, improves the heat transfer efficiency of the condensate, reduces the resistance of the liquid during flow, and promotes the return of the condensate.

[0038] like Figure 3 As shown, in some embodiments, the return flow channel includes a Tesla valve-shaped flow channel. A Tesla valve is a valve structure without moving parts used to control the direction of fluid flow. Through its special design, it utilizes fluid momentum and eddy current effects to achieve fluid flow in one direction while simultaneously blocking fluid flow in the other. Using a Tesla valve-shaped flow channel ensures unidirectional condensate return, avoiding the risk of congestion and thus enhancing return flow capability.

[0039] In some embodiments, the ceramic materials used for the tube body and the cover body include at least one of silicon carbide ceramics, silicon nitride ceramics and alumina ceramics. These ceramic materials have high hardness, high melting point, excellent high temperature resistance and chemical stability, and can maintain stable performance in the high temperature and corrosive environment of sodium heat pipe 1, while also having good thermal conductivity.

[0040] In some embodiments, the ceramic support material includes silicon carbide and / or silicon nitride. Silicon carbide and / or silicon nitride, as ceramic support materials, both possess strong chemical stability and good rigidity, making them suitable for processing return channels and serving as a support substrate covering carbon nanotubes, as well as maintaining stability in the high-temperature and corrosive environment of the sodium heat pipe 1.

[0041] This application also provides a heat transfer device including the sodium heat pipe as described above, the sodium heat pipe being used to transfer heat between a heat source and a cold source.

[0042] like Figure 5 As shown, this application also provides a method for manufacturing a corrosion-resistant sodium heat pipe, which is used to manufacture the above-mentioned sodium heat pipe and heat transfer device. The manufacturing method includes: Provides tubes and caps made of ceramic material; A liquid-absorbing core is provided, comprising a ceramic support and carbon nanotubes. Manufacturing the liquid-absorbing core includes: processing a return flow channel inside the ceramic support; and covering the surface of the ceramic support forming the return flow channel with carbon nanotubes. Place the suction core inside the cavity of the tube; The cap is sealed to the tube body, for example by brazing, and sodium working fluid is poured into the cavity of the tube body and then sealed.

[0043] Specifically, in some embodiments, manufacturing the liquid-absorbing core also includes manufacturing carbon nanotubes using chemical vapor deposition and sintering the carbon nanotubes onto the surface of a ceramic support to form a return flow channel using a spark plasma process.

[0044] Specifically, in some embodiments, providing tubes and caps made of ceramic materials includes: mixing and molding ceramic raw materials, and then sintering them at high temperature under an inert atmosphere or vacuum.

[0045] Specifically, in some embodiments, filling the cavity of the tube with sodium working fluid and sealing it includes: Sodium working fluid is injected into the cavity of the tube through the injection hole on the cap. The injection volume of sodium working fluid is 50% to 150% of the saturated absorption capacity of the absorbent core. After freezing below the condensation temperature of liquid sodium, the gas is degassed and the filling hole is sealed.

[0046] like Figure 1 , Figure 2 As shown, the following provides a first example of sodium heat pipe 1: The body 10 and cover 20 of the sodium heat pipe 1 are made of silicon carbide ceramic.

[0047] The absorber 30 of the sodium heat pipe 1 is made of silicon carbide / carbon nanotube composite material. Silicon carbide serves as the support, with its inner surface machined into a vein-like reflux channel. Carbon nanotubes cover the surface of the silicon carbide support, forming the vein-like reflux channel, providing capillary pressure for condensate reflux. Under the capillary pressure provided by the carbon nanotubes, the condensate flows back to the evaporation section along the vein-like reflux channel. The vein-like reflux channel is biomimetic to the branching and network structure of plant leaf veins. This design effectively increases the surface area, improves the heat transfer efficiency of the condensate, and reduces resistance during liquid flow through the branching and network structure, promoting condensate reflux.

[0048] The outer wall of the wick 30 (support) abuts against the inner wall of the tube 10 to reduce the thermal resistance between the wick 30 and the tube 10, improve the heat transfer path from the tube 10 to the wick 30, and enable the heat from the evaporation section to be efficiently transferred to the sodium working fluid inside the wick 30, thereby improving the overall heat transfer efficiency of the sodium heat pipe 1. This helps to avoid poor condensate backflow under conditions of reduced corrosion, and efficiently completes the heat transfer task.

[0049] During operation, the sodium liquid absorbs heat in the evaporation section of sodium heat pipe 1 and undergoes phase change vaporization. Subsequently, the sodium vapor diffuses to the condensation section and undergoes phase change liquefaction, releasing heat.

[0050] The manufacturing method of the sodium heat pipe 1 includes the following steps: Step S101. Processing the tube body 10 and the cap body 20: Prepare carbon and silicon sources as raw materials for preparing silicon carbide. The carbon source can be an organic substance such as polystyrene, and the silicon source can be a silicon material such as silicon dioxide. Mix the carbon and silicon sources evenly in a certain proportion, fill the mixture into a mold, and shape it into a tube body and a circular cap body. Perform high-temperature heat treatment on the shaped mixture to react and generate silicon carbide at high temperature. The heat treatment usually needs to be carried out in an inert atmosphere or in a vacuum to avoid oxidation reaction. After the heat treatment is completed, cool the obtained silicon carbide tube body and circular cap body, and clean them to remove residual substances.

[0051] Step S102. Contact one end of the tube body 10 with the cover body 20: Select appropriate laser power, focal length, and focal position parameters according to the characteristics of silicon carbide; focus the laser beam on the surface of silicon carbide, and the high-energy laser beam locally heats the surface to above the melting point to form a molten pool. During laser irradiation, control the formation and stability of the molten pool to ensure welding quality; place the silicon carbide component to be welded in a suitable position so that it contacts and fuses with the molten pool; after laser irradiation stops, the welded part begins to cool and solidify, forming a strong weld; optionally, perform cleaning, polishing, and other treatments to improve the surface quality of the welded part.

[0052] Step S103. Preparation of the liquid-absorbing core 30: A cylindrical silicon carbide support can be prepared by high-temperature molding and sintering. The silicon carbide tube is fixed on a CNC milling machine, and the interior of the silicon carbide tube is accurately machined according to the leaf vein-shaped return flow channel. The silicon carbide support is then cleaned. A metal substrate such as nickel or iron is selected, and catalyst nanoparticles such as cobalt are deposited on its surface. The pre-prepared substrate is placed in a chemical vapor deposition (CVD) reaction chamber, and carbon nanotubes are prepared by chemical vapor deposition. The catalyst is heated to an appropriate temperature, and carbon source gases such as methane and ethylene and carrier gases such as hydrogen are introduced. Carbon nanotubes are prepared under suitable temperature and pressure. By controlling the reaction conditions, the diameter, length, and structure of the carbon nanotubes can be controlled. The sample containing carbon nanotubes is placed in a discharge plasma treatment device, where the carbon nanotubes are sintered onto the surface of a silicon carbide support to form vein-like reflux channels using the discharge plasma process. During the treatment, parameters such as the power, temperature, and treatment time of the discharge plasma need to be controlled to ensure that the carbon nanotubes effectively cover the support surface without damaging the silicon carbide support. After treatment, the silicon carbide support is cleaned to ensure that the sample surface is clean and free of residue. Optionally, a microscope or other equipment can be used to inspect the treated sample to confirm that the carbon nanotubes have been uniformly covered on the surface of the support channels.

[0053] Step S104. Place the prepared silicon carbide / carbon nanotube liquid absorbent core 30 into the tube body 10, so that the outer wall of the liquid absorbent core 30 is in close contact with the inner wall of the tube body 10.

[0054] Step S105. Bring the other end of the tube 10 into contact with the cover 20 and seal the tube 10 using laser welding.

[0055] Step S106. Liquid working fluid filling and degassing: Inject approximately 50% to 150% of the liquid working fluid saturated by the absorbing core 30 into the tube body 10 through the filling hole 21. After freezing at a temperature lower than that of liquid sodium condensation, perform a first degassing and a second degassing, and seal the filling hole 21.

[0056] like Figure 3 , Figure 4 As shown, a second example of sodium heat pipe 1 is provided below: The body 10 and cover 20 of the sodium heat pipe 1 are made of alumina ceramic.

[0057] The wick 30 of the sodium heat pipe 1 is made of silicon nitride / carbon nanotube composite material. Silicon nitride serves as the support, with a Tesla valve-shaped return channel machined inside. Carbon nanotubes cover the surface of the silicon nitride support, forming the Tesla valve-shaped return channel, providing capillary pressure for condensate return. The Tesla valve-shaped return channel exhibits a continuous wave / serrated texture structure, utilizing fluid momentum and eddy current effects to achieve smooth condensate flow in one direction and prevent backflow in the opposite direction.

[0058] The outer wall of the wick 30 (support) abuts against the inner wall of the tube 10 to reduce the thermal resistance between the wick 30 and the tube 10, improve the heat transfer path from the tube 10 to the wick 30, and enable the heat from the evaporation section to be efficiently transferred to the sodium working fluid inside the wick 30, thereby improving the overall heat transfer efficiency of the sodium heat pipe 1. This helps to avoid poor condensate backflow under conditions of reduced corrosion, and efficiently completes the heat transfer task.

[0059] During operation, the sodium liquid absorbs heat in the evaporation section of sodium heat pipe 1 and undergoes phase change vaporization. Subsequently, the sodium vapor diffuses to the condensation section and undergoes phase change liquefaction, releasing heat.

[0060] The manufacturing method of the sodium heat pipe 1 includes the following steps: Step S201. Processing the tube body 10 and the cover body 20: Thermally decompose aluminum hydroxide at high temperature to generate alumina powder; mix the alumina powder with additives evenly, and then form it into a tube body and a round plate-shaped cover body by pressing or injection molding; place the formed tube body and round plate (cover body) in a high-temperature furnace for sintering treatment, and under controlled temperature and atmosphere, make the powder particles combine into a dense ceramic material; after sintering, process and trim, such as cutting and grinding, so that the round plate reaches the required size and surface flatness, and clean and dry.

[0061] Step S202. Connect one end of the tube body 10 to the cover body 20 and seal the connection using laser welding: Ensure the alumina ceramic surface is clean and the joint is flat; set the laser welding parameters, such as power, focal length, and welding speed, according to the properties and requirements of the alumina ceramic; start the laser welding equipment and irradiate the joint with the laser beam to locally heat it to a high temperature, thereby achieving the fusion of the alumina ceramic; control the parameters during the welding process to ensure welding quality; after welding, perform appropriate cooling treatment to avoid sudden temperature changes that could lead to cracks or deformation.

[0062] Step S203. Preparation of the liquid-absorbing core 30: The silicon nitride support can be prepared by hot pressing sintering, that is, silicon nitride powder and a small amount of additives (such as magnesium oxide, aluminum oxide, iron oxide, etc.) are hot-pressed and sintered into a cylindrical shape under a pressure of more than 19.6 MPa and a temperature of 1600-1700℃. Generally, the product prepared by hot pressing sintering has a higher density and better performance than the product prepared by reaction sintering. The silicon nitride tube is fixed on a CNC milling machine, and the inside of the silicon nitride tube is accurately machined according to the Tesla valve-shaped return channel. The silicon nitride support is then cleaned. Carbon nanotubes are prepared using a chemical vapor deposition method that is largely the same as in the first example, and carbon nanotubes are sintered onto the surface of the silicon nitride support to form the Tesla valve-shaped return channel using a spark plasma process. After the treatment is completed, the silicon nitride / carbon nanotube composite material is cleaned to confirm that the carbon nanotubes have been uniformly covered on the surface of the support forming the channel.

[0063] Step S204: Place the prepared silicon nitride / carbon nanotube liquid absorbent core 30 into the tube body 10, so that the outer side wall of the liquid absorbent core 30 abuts against the inner side wall of the tube body 10.

[0064] Step S205. Bring the other end of the tube 10 into contact with the cover 20 and seal the tube 10 using laser welding.

[0065] Step S206. Liquid working fluid filling and degassing: Inject approximately 50% to 150% of the liquid working fluid saturated by the absorbing core 30 into the tube body 10 through the filling hole 21. After freezing at a temperature lower than that of liquid sodium condensation, perform primary and secondary degassing, and seal the filling hole 21.

[0066] In summary, the beneficial technical effects of this application include, but are not limited to, at least one of the following: The sodium heat pipe provided in this application uses ceramic materials for both the tube body and the cap, which reduces corrosion problems caused by chemical reactions between the metal outer shell (such as stainless steel) and the sodium working fluid. The wick uses a composite structure of a ceramic support and carbon nanotubes. Carbon nanotubes, as an allotrope of carbon, have good chemical compatibility with sodium working fluid. Compared with traditional nickel-based metal wire wicks, this avoids the problem of nickel precipitation in the sodium solution causing wire corrosion and pore size damage. By incorporating a return flow channel inside the ceramic support, a clear return path is provided for the condensate, enhancing the condensate return capacity and ensuring the long-term stable operation of the sodium heat pipe. Compared with traditional metal wire mesh wicks, this avoids problems such as excessive return resistance due to gaps between mesh layers and fluctuations in return resistance due to unstable winding tightness.

[0067] While this application discloses preferred embodiments as described above, it is not intended to limit the scope of this application. Any changes and modifications can be made by those skilled in the art without departing from the spirit and scope of this application. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application, without departing from the content of the technical solution of this application, fall within the protection scope defined by the claims of this application.

Claims

1. A sodium heat pipe, characterized in that, include: The tube body has a cavity inside, and the cavity contains a sodium working substance; A cover body, wherein the cover body is sealed to the end of the tube body; A suction core, wherein the suction core is disposed within the cavity; wherein... The tube body and the cover body are made of ceramic material; The liquid-absorbing core includes a ceramic support and carbon nanotubes. The ceramic support has a reflux channel inside, and the carbon nanotubes cover the surface of the ceramic support that forms the reflux channel. The carbon nanotubes are used to provide capillary pressure for the flow of the sodium working fluid.

2. The sodium heat pipe according to claim 1, characterized in that, The return flow channel includes a leaf vein-shaped flow channel.

3. The sodium heat pipe according to claim 1, characterized in that, The return flow channel includes a Tesla valve-shaped flow channel.

4. The sodium heat pipe according to claim 1, characterized in that, The ceramic material used for the tube body and the cover body includes at least one of silicon carbide ceramic, silicon nitride ceramic, and alumina ceramic.

5. The sodium heat pipe according to claim 1, characterized in that, The ceramic support is made of silicon carbide and / or silicon nitride.

6. A heat transfer device, characterized in that, The heat transfer device includes a sodium heat pipe as described in any one of claims 1 to 5, the sodium heat pipe being used to transfer heat between a heat source and a cold source.

7. A method for manufacturing a sodium heat pipe, characterized in that, The manufacturing method for producing a sodium heat pipe as described in any one of claims 1 to 5 comprises: The tube body and the cap body are provided, both made of ceramic material. The liquid-absorbing core is provided, the liquid-absorbing core comprising the ceramic support and the carbon nanotubes, and the liquid-absorbing core is provided by: processing the return flow channel inside the ceramic support; and covering the surface of the ceramic support forming the return flow channel with the carbon nanotubes. The suction core is arranged inside the cavity of the tube body; The cover is sealed to the tube, and sodium working fluid is injected into the cavity of the tube and then sealed.

8. The manufacturing method according to claim 7, characterized in that, The liquid-absorbing core also includes manufacturing the carbon nanotubes using chemical vapor deposition and sintering the carbon nanotubes onto the surface of the ceramic support to form the return flow channel using a spark plasma process.

9. The manufacturing method according to claim 7, characterized in that, The provision of tubes and caps made of ceramic materials includes: mixing ceramic raw materials and molding them, followed by high-temperature sintering under an inert atmosphere or vacuum.

10. The manufacturing method according to claim 7, characterized in that, The process of injecting sodium working fluid into the cavity of the tube and sealing it includes: Sodium working fluid is injected into the cavity of the tube through the injection hole on the cover, and the injection volume of sodium working fluid is 50% to 150% of the saturated absorption capacity of the absorbent core. After freezing below the liquid sodium condensation temperature, the gas is degassed and the injection hole is sealed.

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