Phase change thermal diode based on directional transportation and implementation method thereof

Abstract

The invention provides a phase change thermal diode based on directional transportation and an implementation method thereof, and the phase change thermal diode comprises a tube wall, a directional transportation capillary structure, a boiling enhancement capillary structure and a liquid working medium. The inner side of the pipe wall is of a directional transportation capillary structure and a boiling enhancement capillary structure; the directional transportation capillary structure has a function of directionally transporting a liquid working medium; the boiling enhancing capillary structure has a boiling enhancing effect; the interior of the pipe wall is a vacuum or negative pressure environment and is filled with a compatible liquid working medium; the directional transportation capillary structure and the boiling enhancement capillary structure are integrally formed in a spinning mode. The defects that an existing phase change thermal diode is tedious in preparation process, not suitable for large-scale preparation, limited in application range and the like can be overcome.

Description

Technical Field

[0001] The invention relates to the technical field of phase change thermal diode manufacturing, and in particular to a phase change thermal diode based on directional transport and a realization method thereof. Background Art

[0002] Since the thermal diode is a highly efficient one-way heat transfer element, it has the advantages of one-way controllable heat transfer and high heat transfer phase ratio, and it also has the characteristics of no power input, compact size and no noise, so it has been used to a certain extent in various fields of national economic construction. In the field of aerospace, it plays an important role in the heat dissipation of internal devices. When facing the sun, the heat dissipation device reverses the heat transfer and damages the electronic devices. Therefore, the emergence of thermal diodes with one-way heat conduction can well protect electronic devices.

[0003] The preparation of the directional transport capillary structure of the existing phase-change thermal diode is often limited by the shape of the tube structure and cannot be realized, and a gravity-type thermal diode without structure is often prepared. However, gravity has a great influence on it, and it often cannot work normally in zero gravity or low gravity. Therefore, how to make a phase-change thermal diode with a simple processing flow and good thermal polarity is of great significance to aerospace.

[0004] No invention patents that can solve the above problems have been found in publicly published documents and publications. The following inventions are slightly related to it, and the specific contents are as follows:

[0005] 1. "A flat-plate thermal diode, a preparation method thereof and a solar thermal collector", application number: CN202210156312.6, publication / announcement date: 2022 / 05 / 24. The present invention provides a flat-plate thermal diode, a preparation method thereof and a solar thermal collector, and relates to the field of thermal diode technology. Specifically, the flat-plate thermal diode includes a hydrophilic plate, a hydrophobic plate and a seal arranged between the hydrophilic plate and the hydrophobic plate; at least one closed cavity formed between the hydrophilic plate, the hydrophobic plate and the seal is a water vapor zone, and the water vapor zone is used to carry a heat transfer medium; in the water vapor zone, a capillary wick is arranged on the surface of the hydrophilic plate. The flat-plate thermal diode of the present invention has excellent unidirectional heat transfer capability and reverse heat insulation capability, controllable energy transfer direction, and high heat transfer efficiency; at the same time, it has a certain degree of designability and can meet the heat transfer requirements of different scenarios.

[0006] 2. "An adaptive thermal diode and its manufacturing method" Application number: CN202310453983.3, Publication / Announcement Date: 2023 / 08 / 01. The present invention provides an adaptive thermal diode and its manufacturing method, wherein the adaptive thermal diode includes an upper cover body and a lower shell body that are interlocked, and the upper cover body and the lower shell body are enclosed to form a sealed fluid channel cavity; an evaporation end, a silicon wafer substrate and a condensation end are respectively provided in the lower shell body from left to right, and a plurality of grooves distributed in a linear array are provided on the silicon wafer substrate, and the depth of each groove gradually decreases from the evaporation end to the condensation end, and the width of each groove gradually decreases from the evaporation end to the condensation end, so that a wedge structure is formed between each adjacent two grooves, and the upper surface width of each wedge structure gradually widens from the evaporation end to the condensation end; each groove and each wedge structure cooperate with each other to form a microchannel structure with gradient wettability. The adaptive thermal diode provided by the present invention can enable the heat dissipation medium to achieve adaptive movement in the horizontal direction to successfully reflux the condensation end, so that the thermal diode can achieve unidirectional heat transfer in different directions.

[0007] 3. "A Gravity Thermal Diode Based on Porous Media and Hydrophobic Surface" Application Number: CN202210340929.3, Publication / Announcement Date: 2023 / 03 / 14. The present invention is a gravity thermal diode based on porous media and hydrophobic surfaces, the gravity thermal diode comprising: a sealed heat-conducting shell, a porous capillary wick medium, the inner wall on one side of the heat-conducting shell is covered with porous capillary wick medium, the inner wall on the other side of the heat-conducting shell is coated with a hydrophobic coating, the interior of the heat-conducting shell is a vacuum cavity, and a small amount of pure water to remove dissolved gases is installed at the bottom of the heat-conducting shell. This design can not only realize the directional conduction of thermal energy and effectively reduce the energy consumption of indoor heating, but also has a reasonable structural design and realizes the environmentally friendly utilization of thermal energy in the atmosphere.

[0008] 4.《A hierarchical start-up thermal diode and its processing method》》Application number: CN202310631869.5, Publication / Announcement Date: 2024 / 02 / 20. The present invention relates to the field of heat pipe technology, and in particular to a hierarchical start-up thermal diode, comprising an outer tube, wherein the outer tube is provided with a mutually closed and independent first cavity, a second cavity and a third cavity in sequence along the axial direction, each of which is connected to a liquid-filled tube communicating with its interior, each of which is filled with different heat transfer media, and each of which is equipped with a liquid wick for transferring the media. The heat pipe can only transfer heat in a specific heat transfer direction, and cannot transfer heat in the opposite direction. And unlike traditional thermal diodes, the present invention controls the different properties of the working heat transfer medium inside the heat pipe, so that it has the characteristics of low-temperature heat work, and has the effect of hierarchical start-up unidirectional heat transfer, which can not only achieve the effect of unidirectional heat transfer under zero gravity conditions, but also have the hierarchical start-up unidirectional heat transfer effect in long-distance heat transport. The present invention also provides a hierarchical start-up thermal diode processing method.

[0009] 5. "A Tesla valve type ultra-thin planar thermal diode based on phase change heat transfer technology" Application number: CN202210025916.7, Publication / Announcement Date: 2022 / 05 / 13. The present invention relates to a Tesla valve type ultra-thin planar thermal diode based on phase change heat transfer technology, comprising a tube body, in which an evaporation end, a liquid working fluid cavity, a Tesla valve flow channel, a liquid wick filled with liquid working fluid, and a condensation end are arranged; the liquid wick is arranged in the liquid working fluid cavity; the condensation end, the liquid wick and the evaporation end are connected in sequence to form a liquid working fluid passage, and the evaporation end, the Tesla valve flow channel and the condensation end are connected in sequence to form a gaseous working fluid passage. The unidirectional thermal conductivity of the ultra-thin planar thermal diode is improved by utilizing the acceleration characteristics of the Tesla valve on the fluid and the unidirectional conductivity. During forward heating, the gaseous working fluid flows from the evaporation end to the condensation end, and flows downstream in the Tesla valve, with small air resistance and high thermal conductivity; during reverse heating, the gaseous working fluid flows from the condensation end to the evaporation end, and flows countercurrently in the Tesla valve, with large air resistance and low thermal conductivity, thus achieving the effect of a thermal diode, which can be widely used in the microelectronics industry.

[0010] Patent 1 utilizes the hydrophilic structure on the surface of the structure to achieve unidirectional heat transfer, Patent 2 utilizes the inclined condensation end and the V-shaped groove on the base to achieve unidirectional liquid transfer, Patent 3 utilizes the hydrophilic and hydrophobic surface of the structure and gravity to achieve unidirectional heat transfer, Patent 4 utilizes the method of dividing the heat pipe into sections and infusing working fluids with different boiling temperatures to achieve unidirectional heat transfer from the low boiling point working fluid section to the high boiling point working fluid section, and Patent 5 utilizes the unidirectional conductivity of the Tesla valve to achieve unidirectional heat conduction. Summary of the invention

[0011] The technical problem solved by the present invention is to provide a phase change thermal diode structure based on directional transport, so as to solve the shortcomings of the existing phase change thermal diode, such as complicated preparation process, unsuitability for large-scale preparation, and limited scope of use.

[0012] The second technical problem solved by the present invention is to provide a method for preparing a phase-change thermal diode structure based on directional transport.

[0013] The technical solution of the present invention is: a phase change thermal diode structure based on directional transport, characterized in that it consists of a tube wall, a directional transport capillary structure, a boiling enhanced capillary structure and a liquid working medium; the directional transport capillary structure is located on the inner side of the tube wall in the heat source contact area, and has the function of directional transport of the liquid working medium; the boiling enhanced capillary structure is located on the inner side of the tube wall in the heat source contact area, and has the effect of enhancing boiling; the inside of the tube wall is a vacuum or negative pressure environment, and the inside is filled with a compatible liquid working medium; the directional transport capillary structure and the boiling enhanced capillary structure are formed as one piece by spinning.

[0014] Preferably, the tube wall is made of metal materials such as copper, aluminum, stainless steel, etc.

[0015] Preferably, the liquid working medium is a liquid compatible with the tube wall, such as copper, and the liquid working medium may be deionized water, ethanol, or the like;

[0016] Preferably, the directional transport capillary structure and boiling enhancement capillary structure are spun on the inner side of the tube wall;

[0017] Preferably, the micron-scale V-shaped prisms of the directional transport capillary structure are evenly arranged along the diode axis or arranged along the tube wall in an Archimedean spiral.

[0018] Preferably, the boiling enhanced capillary structures are spherical protrusions, which are evenly arranged along the diode axis or arranged along the tube wall in the form of an Archimedean spiral.

[0019] Preferably, the spiral mandrel is composed of two wedge-shaped semicircular rods, and the surface of the spiral mandrel has a directional transport capillary reverse structure and a boiling enhanced capillary reverse structure, and the two structures are obtained by laser milling.

[0020] The method for preparing the phase-change thermal diode based on directional transport comprises the following steps:

[0021] (1) Preparation of the spin-shrink mandrel: The directional transport capillary anti-structure and boiling enhanced capillary anti-structure are milled on the surface of the mandrel by laser, and the corresponding length is determined by the specific working requirements of the thermal diode. At the same time, the mandrel is cut into a wedge shape along the diagonal by wire cutting, and the mandrel is fixed in the thermal diode shell by the opposite movement of the wedge planes.

[0022] (2) Preparation of tube wall with capillary structure: The preparation of directional transport capillary structure and boiling enhanced capillary structure is realized through existing heat pipe spinning equipment.

[0023] (3) Enhanced treatment: The directional transport capillary structure adopts hydrophobic treatment, and the boiling enhanced capillary structure adopts hydrophilic treatment to further enhance the heat transfer capacity.

[0024] (4) Shell and plate sealing: Cut a certain length of the shell and use the method of shrinking and spot welding to seal one end of the shell and only shrink the other end to form a small diameter shell for injection;

[0025] (5) Liquid injection and degassing: A certain amount of liquid working fluid is injected into the heat pipe using a perfusion system, and the thermal diode is prepared through primary and secondary degassing;

[0026] (6) Post-processing of thermal diode: The thermal diode is straightened and shaped to meet the shape requirements, and surface treatment is achieved through cleaning, anti-oxidation treatment, etc.

[0027] The beneficial effects of the present invention compared with the prior art are:

[0028] (1) The internal structure of the phase-change thermal diode based on directional transport is simple, and the directional transport capillary structure and the boiling enhanced capillary structure are formed in one piece by spinning, which further enhances the heat transfer capacity of the thermal diode.

[0029] (2) The thermal diode preparation process of the present invention adopts the copper-water heat pipe process, which promotes the maturity of the thermal diode preparation process and can realize the batch preparation of phase change thermal diodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the cross-section of the phase-change thermal diode structure based on directional transport;

[0031] Figure 2 Schematic diagram based on the revolving mandrel

[0032] Figure 3 Schematic diagram of the spin-pressing preparation of phase-change thermal diodes for directional transport;

[0033] In the figure, 1, tube wall; 2, directional transport capillary structure; 3, boiling enhanced capillary structure; 4, directional transport capillary reverse structure; 5, boiling enhanced capillary reverse structure; 6, spiral mandrel; 7, ball; DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the embodiments.

[0035] like Figures 1 to 3As shown, a method for preparing a phase-change thermal diode based on directional transport includes: a tube wall 1, a directional transport capillary structure 2, a boiling enhanced capillary structure 3 and a compatible liquid working medium; a ball 7 is thermally shrunk on the outer surface of the tube shell 1, and the directional transport capillary anti-structure 4 and the boiling enhanced capillary anti-structure 5 on the surface of the shrunk mandrel 6 are copied to the inner wall of the tube shell to realize the preparation of the directional transport capillary structure 2 and the boiling enhanced capillary structure 3. Then, a phase-change thermal diode based on directional transport is formed through a conventional heat pipe process.

[0036] The smart shrinking mandrel 6 is composed of two wedge-shaped semicircular rods, and the surface of the shrinking mandrel has a directional transport capillary anti-structure 4 and a boiling enhanced capillary anti-structure 6, both of which are obtained by laser milling. The wedge-shaped structure of the smart shrinking mandrel achieves close contact between the mandrel and the tube shell by pressing against each other.

[0037] Example 1

[0038] A phase-change thermal diode structure based on directional transport and a preparation method thereof, comprising the following steps:

[0039] (1) Preparation of the spin-shrink mandrel: The directional transport capillary anti-structure 4 and the boiling enhanced capillary anti-structure 5 are milled on the surface of the spin-shrink mandrel 6 by laser, and the corresponding lengths are determined by the specific working requirements of the thermal diode. At the same time, the mandrel is cut into a wedge shape along the diagonal by wire cutting, and the mandrel is fixed in the thermal diode shell by the opposite movement of the wedge planes.

[0040] (2) Preparation of tube wall with capillary structure: Through existing heat pipe spinning equipment, the ball 7 is heat-spun on the outer surface of the tube shell 1 to achieve the preparation of the directional transport capillary structure 2 and the boiling enhanced capillary structure 3.

[0041] (3) Strengthening treatment: The directional transport capillary structure 2 is treated with hydrophobicity, and the boiling enhanced capillary structure 3 is treated with hydrophilicity to further enhance the heat transfer capacity.

[0042] (4) Shell and plate sealing: Cut a certain length of the shell and use the method of shrinking and spot welding to seal one end of the shell and only shrink the other end to form a small diameter shell for injection;

[0043] (5) Liquid injection and degassing: A certain amount of liquid working fluid is injected into the heat pipe using a perfusion system, and the thermal diode is prepared through primary and secondary degassing;

[0044] (6) Post-processing of thermal diode: The thermal diode is straightened and shaped to meet the shape requirements, and surface treatment is achieved through cleaning, anti-oxidation treatment, etc.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

[0046] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A phase change thermal diode based on directional transport, characterized in that: Including tube wall, directional transport capillary structure, boiling enhanced capillary structure and liquid working medium; The inner side of the tube wall is a directional transport capillary structure and a boiling enhanced capillary structure; the directional transport capillary structure has the function of directional transport of liquid working fluid; the boiling enhanced capillary structure has the effect of enhancing boiling; the inside of the tube wall is a vacuum or negative pressure environment, and the inside is filled with compatible liquid working fluid; the directional transport capillary structure and the boiling enhanced capillary structure are formed by spinning in one piece.

2. The diode according to claim 1, characterized in that: The directional transport capillary structure is a plurality of micrometer-scale V-shaped prisms evenly arranged along the diode axis or arranged along the tube wall in the form of an Archimedean spiral.

3. The diode according to claim 1, characterized in that: The boiling enhanced capillary structure is a plurality of spherical protrusions, which are evenly arranged along the diode axis or arranged along the tube wall in the form of an Archimedean spiral.

4. The diode according to claim 1, characterized in that: The tube wall is made of metal materials, including copper, aluminum and stainless steel.

5. The diode according to claim 4, characterized in that: The liquid working medium is a liquid compatible with the tube wall.

6. A method for preparing a phase-change thermal diode structure based on directional transport, characterized in that include: Prepare the spin-shrink mandrel: mill out the directional transport capillary reverse structure and the boiling enhanced capillary reverse structure on the surface of the mandrel; Preparation of a tube wall with a capillary structure: fixing the spin-shrink mandrel in a tube shell with a smooth inner wall, and preparing a directional transport capillary structure and a boiling enhanced capillary structure on the inner wall of the tube shell by a hot pipe spinning device; Strengthening treatment: hydrophobic treatment is used for directional transport capillary structure, and hydrophilic treatment is used for boiling enhanced capillary structure; Shell and plate sealing: Cut a certain length of tube shell, use shrinking and spot welding to seal one end of the tube shell, and only shrink the other end to achieve a small diameter tube shell for liquid injection; Liquid injection and degassing: Inject liquid working fluid into the heat pipe, and prepare the thermal diode through primary and secondary degassing; Post-processing of thermal diode: straighten and reshape the thermal diode to make its shape meet the requirements, and perform surface treatment by cleaning and anti-oxidation treatment.

7. The method according to claim 6, characterized in that: The shrinking core rod is cut into a wedge shape along a diagonal line by a wire cutting method, and the core rod is fixed in the thermal diode shell by the opposite movement of the wedge planes.

8. The method according to claim 6, characterized in that: The directional transport capillary anti-structure and boiling enhanced capillary anti-structure on the surface of the spiral mandrel are obtained by laser milling.

9. The method according to claim 6, characterized in that: The directional transport yarn structure and the boiling-increased capillary structure are integrally formed based on a spin-shrinking process.

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