Temperature-responsive composite origami structure intelligent liquid-absorbing core and flexible heat pipe and manufacturing method

Abstract

This invention discloses a temperature-responsive composite origami structure intelligent liquid-absorbing core, a flexible heat pipe, and a manufacturing method. The intelligent liquid-absorbing core has a composite origami structure, including a folded skeleton and a porous thermal response unit. The folded skeleton has a fixed end, and extends from the fixed end to form a structure with a periodic profile curve in its cross-section. The porous thermal response unit is arranged on the folded skeleton and includes a periodic array of micropores. When the temperature changes, it stretches or contracts with the fixed end as a base point, changing the distance between two adjacent cuboids, thereby adjusting the overlap of the micropore spacing and achieving intelligent response of the pore size. Furthermore, the porous thermal response unit based on the origami structure has full-section flexibility, enabling intelligent adjustment of the liquid-absorbing core pore size according to temperature. It has high heat dissipation performance, can be bent at large angles, with small radii, and multiple times, has a simple structure, high stability, and long service life, and is suitable for large-scale production.

Description

Technical Field

[0001] This invention belongs to the field of intelligent heat transfer technology, specifically relating to a temperature-responsive composite origami structure intelligent liquid-absorbing core, a flexible heat pipe, and a manufacturing method. Background Technology

[0002] With the development of electronic devices and high-performance computers, the research and application of heat dissipation technology have become particularly important. Phase change heat transfer technology, with its advantages of high heat transfer efficiency, high stability, long lifespan, and low cost, has become the primary choice for solving the heat dissipation problem of high heat flux density in electronic devices. Heat pipes, as a commonly used and typical phase change heat transfer element, have gained high recognition in various fields from aerospace to ground industry. Traditional heat pipe technology, due to its highly efficient heat conduction capabilities, has been widely used in the heat dissipation of various electronic devices, especially in aerospace and ground industry.

[0003] As one of the core components of a heat pipe, the performance of the wick is mainly evaluated by three criteria: high porosity, high permeability, and high capillary force. Common traditional wick structures include microchannel type, powder sintering type, sintered wire mesh type, and foam metal type. Each of these structures has its advantages and disadvantages: the microchannel type has low flow resistance but complex processing and high cost; the powder sintering type has large capillary force and is widely used but has poor permeability; the sintered wire mesh type has controllable porosity and is often used in flexible heat pipes but has high thermal resistance; the foam metal type is inexpensive but has many internal closed pores and is difficult to control in molding. Composite wicks combine the advantages of various wicks to achieve optimal design solutions, such as multi-layer wire mesh composites, wire mesh and powder composites, and powder and groove composites. However, in actual operation, different operating conditions require different optimal capillary forces for the wick: at high power, the pore size at the evaporation end needs to be reduced to provide strong capillary force to promote liquid reflux, while the pore size at the condensation end needs to be increased to reduce flow resistance; the opposite is true at low power. While existing gradient wick structures perform well under single operating conditions, their heat and mass transfer performance significantly deteriorates under large fluctuations in hot-end power, failing to maintain uniform performance across different power levels. Since the wick aperture within the heat pipe is typically fixed, the optimal capillary force required for the wick must change with variations in the heat pipe's operating temperature. Related research has proposed solutions such as adding springs or using complex designs, but these solutions often increase manufacturing complexity and are unsuitable for mass production. Therefore, proposing an intelligent heat pipe concept to improve heat transfer performance has become a solution, focusing on developing a wick with adaptive aperture adjustment. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and to provide a solution that addresses the problems mentioned in the background art.

[0005] One of the technical solutions adopted by this invention to solve its technical problem is as follows: a temperature-responsive composite origami structure intelligent liquid-absorbing core is provided, which has a composite origami structure, including a folded skeleton and a porous thermal response unit; the folded skeleton is made of shape memory alloy material, has a fixed end, and extends from the fixed end to form a structure with a periodic profile curve in cross-section, wherein the design height of the periodic profile curve is adjustable in the range of 0.01 to 100 mm, and the design period T1 is adjustable in the range of 0.02 to 20 mm; the porous thermal response unit is arranged on the folded skeleton and includes a periodic hole array formed by several micropores, wherein the design spacing T2 between adjacent micropores in the same column is adjustable in the range of 0.0002 to 20 mm, and the design spacing T3 between two adjacent columns of micropores is adjustable in the range of 0.0001 to 50 mm.

[0006] In this invention, the composite origami structure is one or more combinations of the following: Miura origami structure, stacked origami structure, polyhedral origami structure, water-bomb origami structure, and triangular cylindrical origami structure.

[0007] In this invention, the periodic contour curve includes trigonometric functions, polynomial functions, exponential functions, logarithmic functions, or inverse trigonometric functions.

[0008] In this invention, the shape memory alloy material includes CuZnAl shape memory alloy or TiNi shape memory alloy, which achieves shrinkage / stretching effects in different working sections at specific temperatures. The phase transformation temperature of the shape memory alloy depends on the material selection and engineering requirements; the phase transformation temperature during shrinkage is 60–100°C, and the phase transformation temperature during stretching is 20–40°C.

[0009] In this invention, the shape of the micropores includes circular, polygonal, elliptical, heart-shaped, and fan-shaped.

[0010] In this invention, the fixed end includes an end piece, a retaining ring, or a retaining ring.

[0011] This invention also provides a method for manufacturing the above-mentioned temperature-responsive composite origami structure intelligent liquid-absorbing core, comprising the following steps:

[0012] Step 1: Design a folded structure with curved and folded arrangement as the basic skeleton. Optimize the periodic contour curve of the folding ladder skeleton design, including design height, design period T1, design length, and bending angle. Optimize the design radius, design shape, design spacing T2 between adjacent micro-holes, and design spacing T3 between two adjacent rows of micro-holes to determine manufacturing parameters and processing schemes. The optimization parameters include the fluid flow resistance of the liquid working medium, the maximum bending stress value, the effective area of ​​the cross-section, and the maximum supporting force index of the structure.

[0013] Step 2: Use laser processing or chemical etching to process a periodic array of holes on the shape memory alloy material that conforms to the manufacturing parameters of Step 1;

[0014] Step 3: Fold and bend the shape memory alloy material to form a folded skeleton, determine the required liquid absorption core cross-sectional shape, and program its temperature response to obtain a temperature-responsive composite origami structure intelligent liquid absorption core.

[0015] In this invention, in step 2, the scanning power of the laser processing is 10 to 100W, the scanning rate is 0.1 to 6.0m / s, and the scanning path includes circles, polygons, ellipses, hearts, or fan shapes.

[0016] The third technical solution adopted by the present invention to solve its technical problem is: to provide a flexible heat pipe, including a flexible shell and a liquid-absorbing core, wherein the liquid-absorbing core adopts a temperature-responsive composite origami structure intelligent liquid-absorbing core as described above.

[0017] In this invention, a sealed space is formed inside the flexible shell and filled with a liquid working medium; the liquid-absorbing core is disposed inside the flexible shell and connected to the flexible shell through a fixed end; the liquid working medium is transported between the liquid-absorbing cores.

[0018] In this invention, the outer shell provides a sealed space through welding to ensure the vacuum level required for operation. The welding process includes one or more of the following: hot-press welding, low-temperature diffusion welding, and ultrasonic welding. The vacuum level is achieved by extracting and removing internal air using relevant machinery and then welding again. The vacuum level is 4–6 kPa.

[0019] In this invention, the outer shell material is one of a highly flexible film, such as a metal film, a polymer film, or a polymer-metal composite film, with a thickness between 0.05 and 0.2 mm. As long as the purpose of this invention is achieved, it can be one or more of the following: a metal film, a polymer film, or a polymer-metal composite film. The types of metal and polymer materials are not limited; as long as the purpose of this invention is achieved, the metal material can be one of copper, aluminum, stainless steel, etc., and the polymer material can be one or more of PP (polypropylene), PE (polyethylene), PET (low-density polyethylene terephthalate), etc.

[0020] In this invention, the working fluid of the flexible heat pipe is anhydrous ethanol, deionized water, or acetone, etc.

[0021] The present invention also provides a method for manufacturing the above-mentioned flexible heat pipe, comprising the following steps:

[0022] Step 1: Cut the outer shell film; design a folded structure with curved and folded arrangement as the basic skeleton; optimize the periodic contour curve of the folded ladder skeleton design, including design height, design period T1, design length, and bending angle; optimize the design radius, design shape, design spacing T2 between adjacent micropores, and design spacing T3 between two adjacent rows of micropores to determine manufacturing parameters and processing scheme; the optimization parameters include the fluid flow resistance of the liquid working medium, the maximum bending stress value, the effective area of ​​the cross section, and the maximum support force index of the structure;

[0023] Step 2: Use laser processing or chemical etching to process a periodic array of holes on the shape memory alloy material that conforms to the manufacturing parameters of Step 1;

[0024] Step 3: Fold and bend the shape memory alloy material to form a folded skeleton, determine the required cross-sectional shape of the liquid absorption core, and program its temperature response to obtain a temperature-responsive composite origami structure smart liquid absorption core.

[0025] Step 4: Encapsulate the temperature-responsive composite origami structure intelligent liquid-absorbing core and liquid working fluid into a flexible shell to form a flexible heat pipe.

[0026] Compared with the prior art, this technical solution has the following advantages:

[0027] 1. This invention utilizes a temperature-responsive shape memory alloy material as the wicking core skeleton. The shape memory material has the characteristic of restoring a preset shape as the temperature changes. Based on this, a porous thermal response unit with several micropores is formed. The sensitive unit with thermal response capability and the porous structure that provides capillary force are combined to form the wicking core, so that the wicking core exhibits different forms at different temperatures, thereby changing the heat transfer path and efficiency.

[0028] 2. The absorbent core is designed with a special origami structure. Temperature differences in the working section cause varying degrees of contraction in the response units, driving changes in the distance between adjacent pages of the origami structure. This alters the micropore spacing and overlap, resulting in a change in the pore size of the porous structure. The absorbent core's pore size can be adaptively adjusted, allowing it to flexibly change its size in response to temperature variations. The origami structure not only increases the surface area of ​​the absorbent core and enhances heat transfer capacity but also enables the entire heat pipe structure to adapt to small deformations, making installation and use more flexible.

[0029] 3. By combining temperature memory alloy materials and origami structure, the capillary force required for liquid reflux is provided, and the sensitive unit cavity provides a vapor channel.

[0030] 4. A porous structure with a thermally responsive sensing unit is used to provide capillary force. By programming the response temperature of the thermally responsive sensing unit, the pore size of the porous structure is adaptively adjusted. The wick structure intelligently matches the optimal balance point of capillary force, permeability, and porosity across the entire power range. For example, at low power, the operating temperature is low, the contraction / expansion deformation of the hot-end sensing unit is small, and the large wick pore size allows for a small amount of vapor with low transmission resistance. At high power, the operating temperature is high, causing large contraction / expansion deformation of the sensing unit. The small wick pore size promotes the return of the working fluid to the hot end, increasing the ultimate power of the heat pipe. Simultaneously, using the thermally responsive sensing unit as the support and driving structure of the wick ensures unobstructed vapor passage while enabling the application of rigid materials in a flexible heat pipe.

[0031] 5. This invention uses a flexible thin film as the heat pipe shell material, and the skeleton of the composite origami-structured intelligent porous wick is made of a thermally responsive material. The skeleton provides the vapor space required for the heat pipe to operate while actively changing its pore size, thus allowing it to expand and contract autonomously when the temperature changes, providing capillary suction force. The flexible heat pipe can adaptively adjust the effective pore size of the wick according to the ambient temperature, significantly improving heat dissipation efficiency and adapting to a wider range of applications. Furthermore, it simplifies the structure of the wick, facilitating large-scale manufacturing.

[0032] 6. The intelligent flexible heat pipe structure of the present invention breaks through the limitations of traditional heat pipes and provides a solution that can automatically adjust the heat transfer performance according to temperature changes. It solves the contradiction between capillary force and flow resistance in the wick structure, and solves the problems of high thermal resistance and low ultimate power caused by the inability of current heat pipes to adaptively adjust the internal wick aperture according to the operating temperature. It has broad application prospects and significant technical advantages. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the liquid suction core and its local micropores;

[0034] Figure 2 This is a schematic diagram of the origami structure of the liquid-absorbing core;

[0035] Figure 3 A schematic diagram of the temperature response of the wick along the extension direction;

[0036] Figure 4 This is a schematic diagram of the overall structure of a flexible heat pipe;

[0037] Among them, 1-liquid suction core, 12-(liquid suction core) upper sheet, 121-periodic micropore array, 122-page, 123-aperture, 13-(liquid suction core) side sheet, 2-fixed end, 3-flexible shell, 4-liquid injection hole, 5-enclosed space; Detailed Implementation

[0038] It should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0039] Example 1

[0040] This embodiment presents a temperature-responsive composite origami structure intelligent liquid-absorbing core 1, such as... Figure 1 and 2 The device features a composite origami structure, including a folded skeleton and a porous thermal response unit. The folded skeleton is made of shape memory alloy and has a fixed end 2. It extends from the fixed end 2 to form a structure with a periodic profile curve in cross-section. The design height of the periodic profile curve is adjustable from 0.01 to 100 mm, and the design period T1 is adjustable from 0.02 to 20 mm. The porous thermal response unit is arranged on the folded skeleton and includes a periodic micropore array 121 formed by several micropores. The design spacing T2 between adjacent micropores in the same column is adjustable from 0.0002 to 20 mm, and the design spacing T3 between two adjacent columns of micropores is adjustable from 0.0001 to 50 mm.

[0041] In this embodiment, the deformation process of the intelligent porous liquid-absorbing core of the temperature-responsive composite origami structure is as follows: Figure 3 As shown in the figure, temperature changes cause a change in the apex angle 123 of the intelligent porous liquid-absorbing core in the composite origami structure, thereby altering the overlap of micropores between different pages 122. This indirectly changes the size of the micropores in the liquid-absorbing core, enabling adaptive adjustment of the core pore size. Simultaneously, it allows for flexible bending at large angles and small radii, with bending effects as shown... Figure 2 As shown.

[0042] This embodiment describes a method for manufacturing a temperature-responsive composite origami structure smart liquid-absorbing core, comprising the following steps:

[0043] Step 1: Design a folded structure with curved and folded arrangement as the basic skeleton. Optimize the periodic contour curve of the folding ladder skeleton design, including design height, design period T1, design length, and bending angle. Optimize the design radius, design shape, design spacing T2 between adjacent micro-holes, and design spacing T3 between two adjacent rows of micro-holes to determine manufacturing parameters and processing schemes. The optimization parameters include the fluid flow resistance of the liquid working medium, the maximum bending stress value, the effective area of ​​the cross-section, and the maximum supporting force index of the structure.

[0044] Step 2: Use laser processing or chemical etching to process a periodic array of holes on the shape memory alloy material that conforms to the manufacturing parameters of Step 1; the scanning power of laser processing is 10-100W and the scanning rate is 0.1-6.0m / s;

[0045] Step 3: Fold and bend the shape memory alloy material to form a folded skeleton, determine the required liquid absorption core cross-sectional shape, and program its temperature response to obtain a temperature-responsive composite origami structure intelligent liquid absorption core.

[0046] Example 2

[0047] The flexible heat pipe heat transfer device of this embodiment includes a flexible shell and the liquid-absorbing core 1 of Embodiment 1. Figure 4 The flexible shell has a closed space 5 inside. The liquid-absorbing core is divided into an upper piece 12 and a side piece 13, both of which are connected to the flexible shell 3 through a fixed end 2.

[0048] The manufacturing method of this embodiment includes the following steps:

[0049] Preliminary preparations: The flexible film is cut to an appropriate size, the composite origami structure intelligent porous liquid-absorbing core is laser-processed or acid-etched to create a micropore array, and the origami structure is processed and temperature response programming is performed;

[0050] Manufacturing Process: Under mold constraints, the flexible shell 3 and the liquid-absorbing core are sealed through a hot-press welding process. After processes such as vacuuming, filling with working fluid, and resealing, the temperature-responsive porous composite origami structure intelligent heat pipe heat transfer device is manufactured. The hot-pressing temperature is 210℃, and a pressure of 0.5MPa is applied. The internal sealed space 5 is evacuated to a vacuum degree of 4-6kPa through the injection hole 4, and the working fluid, which is deionized water, is injected with a filling rate of 50%.

[0051] The principle of adaptive adjustment of the pore size of the intelligent multi-resistant wicking core is as follows: Under low power conditions, the operating temperature is low, the shrinkage / expansion deformation of the hot-end wicking core is small, and the large pore size of the wicking core allows a small amount of vapor to have low transmission resistance; Under high power conditions, the operating temperature is high, which causes the wicking core to shrink / expansion deformation to be large, and the small pore size of the wicking core can promote the return of the working fluid to the hot end, thereby increasing the ultimate power of the heat pipe.

[0052] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A temperature-responsive composite origami structure intelligent liquid-absorbing core, characterized in that: It has a composite origami structure, including a folded body skeleton and a porous thermal response unit. The folded body skeleton is made of shape memory alloy material, has a fixed end, and extends from the fixed end to form a structure with a periodic profile curve in cross-section. The design height of the periodic profile curve is adjustable from 0.01 to 100 mm, and the design period T1 is adjustable from 0.02 to 20 mm. The porous thermal response unit is arranged on the folded body skeleton and includes a periodic micropore array formed by several micropores. The design spacing T2 between adjacent micropores in the same column is adjustable from 0.0002 to 20 mm, and the design spacing T3 between two adjacent columns of micropores is adjustable from 0.0001 to 50 mm.

2. The temperature-responsive composite origami structure intelligent liquid-absorbing core according to claim 1, characterized in that: The composite origami structure is the Miura origami structure.

3. The temperature-responsive composite origami structure intelligent liquid-absorbing core according to claim 1, characterized in that: The periodic profile curve is a trigonometric function curve.

4. The temperature-responsive composite origami structure intelligent liquid-absorbing core according to claim 1, characterized in that: The shape memory alloy material includes CuZnAl shape memory alloy or TiNi shape memory alloy.

5. The temperature-responsive composite origami structure intelligent liquid-absorbing core according to claim 1, characterized in that: The micropores can be circular, polygonal, elliptical, heart-shaped, or fan-shaped.

6. A method for manufacturing a temperature-responsive composite origami structure intelligent liquid-absorbing core as described in any one of claims 1-5, characterized in that: Includes the following steps: Step 1: Design a folded body with curved and folded arrangement as the basic skeleton, and optimize the design height, design period T1, design length and bending angle of the periodic contour curve; The design radius, design shape, design spacing T2, and design spacing T3 of the micropores are optimized to determine the manufacturing parameters and processing scheme. The parameters used for optimization include the fluid flow resistance of the liquid working medium, the maximum bending stress value, the effective area of ​​the cross section, and the maximum supporting force index of the structure. Step 2: Use laser processing or chemical etching methods to process a periodic array of micropores on the shape memory alloy material that conforms to the manufacturing parameters of Step 1; Step 3: Fold and bend the shape memory alloy material to form a folded skeleton, determine the required liquid absorption core cross-sectional shape, and program its temperature response to obtain a temperature-responsive composite origami structure intelligent liquid absorption core.

7. The manufacturing method of a temperature-responsive composite origami structure intelligent liquid-absorbing core according to claim 6, characterized in that: In step 2, the scanning power of laser processing is 10 to 100W, the scanning rate is 0.1 to 6.0m / s, and the scanning path includes circles, polygons, ellipses, hearts, or fan shapes.

8. A flexible heat pipe, characterized in that: It includes a flexible shell and a liquid-absorbing core, wherein the liquid-absorbing core adopts a temperature-responsive composite origami structure intelligent liquid-absorbing core as described in any one of claims 1-5.

9. A flexible heat pipe according to claim 8, characterized in that: The flexible shell forms a sealed space and is filled with a liquid working medium; the liquid-absorbing core is disposed inside the flexible shell and is connected to the flexible shell through a fixed end; the liquid working medium is transported between the liquid-absorbing cores.

10. A method for manufacturing a flexible heat pipe as described in claim 8 or 9, characterized in that: Includes the following steps: Step 1: Cut the outer shell film; design a folded body with curved and folded arrangement as the basic skeleton, and optimize the design height, design period T1, design length and bending angle of the periodic contour curve; The design radius, design shape, design spacing T2, and design spacing T3 of the micropores are optimized to determine the manufacturing parameters and processing scheme. The parameters used for optimization include the fluid flow resistance of the liquid working medium, the maximum bending stress value, the effective area of ​​the cross section, and the maximum supporting force index of the structure. Step 2: Use laser processing or chemical etching methods to process a periodic array of micropores on the shape memory alloy material that conforms to the manufacturing parameters of Step 1; Step 3: Fold and bend the shape memory alloy material to form a folded skeleton, determine the required cross-sectional shape of the liquid absorption core, and program its temperature response to obtain a temperature-responsive composite origami structure smart liquid absorption core. Step 4: Encapsulate the temperature-responsive composite origami structure intelligent liquid-absorbing core and liquid working fluid into a flexible shell to form a flexible heat pipe.

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