Vapor-liquid two-phase separation heat exchange reinforced surface and manufacturing method thereof

Abstract

The invention discloses a vapor-liquid two-phase separation heat exchange reinforced surface and a manufacturing method thereof. The heat exchange surface comprises a heat exchange surface substrate and a capillary porous layer. The heat exchange surface substrate is provided with a plurality of protruding micro-rib structures and concave bottom faces located between the protruding straight ribs. And the capillary porous layer is embedded between the straight rib structures and is in contact with the bottom surface of the recess. The surface has a remarkable vapor-liquid two-phase separation effect, spreading of liquid drops is greatly promoted, the vapor-liquid two-phase competition relation in the boiling heat exchange process is decoupled, a stable thin liquid film and efficient thin film evaporation are formed, and the boiling heat exchange efficiency of the novel surface is enhanced. The vapor-liquid two-phase separation heat exchange reinforced surface is suitable for two-phase cooling of different spraying forms such as pressure spraying and ultrasonic spraying.

Description

Technical Field

[0001] This invention relates to a surface for enhanced boiling heat transfer and a method for manufacturing the same, specifically to a surface for enhanced vapor-liquid two-phase separation heat transfer and a method for manufacturing the same. Background Technology

[0002] Electronic devices are the cornerstone of the information technology industry and the modernization of national defense technology. With the rapid development of electronic information technology and integrated processes, the integration level and single-unit power of electronic devices / equipment are constantly increasing. The packaging density and operating frequency of various electronic devices (such as active phased array radar T / R modules, high-power laser devices, rail electromagnetic launch devices, and high-speed train IGBT devices) are also increasing daily, significantly increasing the power consumption, heat flux density, and working space constraints of electronic devices. For example, the local heat flux density of active phased array radar T / R modules can reach the level of 1 kW / cm². Such high heat flux density, if not efficiently dissipated, will lead to a sharp rise in the operating temperature of electronic devices, severely weakening their performance and reliability, and shortening their lifespan. Therefore, how to achieve efficient cooling and heat dissipation of high heat flux density electronic devices has become a major bottleneck restricting the development of electronic device technology. Boiling heat transfer is an effective way to solve the efficient heat dissipation requirements of high heat flux density devices. Among them, the characteristics of the heat transfer surface are key to affecting the characteristics of boiling heat transfer. Currently, there are many different heat transfer enhancement surfaces, but they cannot meet the heat dissipation requirements of extremely high heat flux densities. Under high heat flux density conditions, heat exchange surfaces are prone to boiling heat transfer crises, such as surface temperature spikes and localized drying. It is important to emphasize that high heat flux densities generate a large amount of vapor on the surface, causing instability in vapor-liquid transport and severely impacting boiling heat transfer capacity. Vapor-liquid two-phase transport is coupled and is inherent in the surface boiling heat transfer process. Current strategies for enhancing boiling heat transfer do not fundamentally decouple the competitive relationship between the vapor and liquid phases, thus making it difficult to achieve heat dissipation targets with heat flux densities exceeding 1000 W / cm². Summary of the Invention

[0003] Purpose of the Invention: The purpose of this invention is to provide a vapor-liquid two-phase separation heat transfer enhancement surface and its manufacturing method, so as to achieve stable and efficient thin liquid film evaporation heat transfer, improve boiling stability and heat transfer performance, and achieve a heat flux density as high as 1500 W / cm². 2 The heat dissipation requirements.

[0004] Technical solution: The vapor-liquid two-phase separation heat transfer enhancement surface of the present invention comprises:

[0005] The heat exchange surface substrate has multiple microrib structures on its surface, and a recessed bottom surface is formed between adjacent microrib structures.

[0006] A capillary porous layer is disposed on the surface of the heat exchange surface substrate, in contact with the surface of the microrib structure and the bottom surface of the recess. A space is formed between the capillary porous layer, the bottom surface of the recess, and the microrib structure, serving as a steam transport channel. The Laplace force maintained during the wetting process of the capillary porous layer... Steam pressure generated by steam transport within the space ,satisfy This achieves vapor-liquid two-phase separation.

[0007] Optionally, the capillary porous layer is U-shaped and connected to the microrib structure and the concave bottom surface; wherein the capillary porous layer is connected to the upper surface of the microrib structure, and the U-shaped bottom of the capillary porous layer is connected to the concave bottom surface.

[0008] Optionally, the material of the capillary porous layer can be a multilayer sintered metal mesh or other highly thermally conductive hydrophilic porous material.

[0009] Optionally, the material of the heat exchange surface substrate is a metal with high thermal conductivity.

[0010] Optionally, the microrib structure can be a straight rib structure, a square rib structure, or a round rib structure.

[0011] Optionally, the recessed bottom surface is also provided with microrib structures whose height is smaller than that of the microrib structure, and the capillary porous layer is in contact with the microrib structures of the recessed bottom surface.

[0012] Optionally, multiple microrib structures are arranged in a periodic array.

[0013] The method for manufacturing the vapor-liquid two-phase separation heat transfer enhancement surface of the present invention includes the following steps:

[0014] Fabricating microrib structures: Multiple microrib structures are formed on the heat exchange surface substrate, with recessed bottom surfaces formed between adjacent microrib structures;

[0015] The capillary porous layer is connected to the surface of the microrib structure and the bottom of the depression. The space between the capillary porous layer, the bottom of the depression and the microrib structure serves as a steam transport channel.

[0016] Furthermore, methods for forming multiple microrib structures on the substrate surface include:

[0017] Microrib structures are formed on the heat exchange surface substrate by cutting or wire cutting.

[0018] A metal powder sintered microrib structure is used on a heat exchange surface substrate;

[0019] Microrib structures were chemically etched onto the heat exchange surface substrate.

[0020] Furthermore, the capillary porous layer is connected to the surface and recessed bottom of the microrib structure by sintering or adhesive bonding.

[0021] Beneficial effects: Compared with the prior art, the significant technical effects of the present invention are as follows: (1) The present invention utilizes micro-rib structure and capillary porous layer to construct axial steam transport channel on the heat exchange surface, which serves as a steam transport path that does not obstruct the liquid phase transport direction, thereby reducing the steam momentum along the direction that obstructs the liquid phase transport; this strategy decouples the competitive relationship between the vapor and liquid phases, delays the vapor-liquid transport instability behavior, and can significantly increase the critical heat flux density of the heat exchange surface; (2) The porous capillary structure can also greatly promote the spread of droplets on the heat exchange surface. The formation of a thin liquid film synergistically enhances the vapor-liquid two-phase transport, achieving stable and efficient thin liquid film evaporation heat transfer, significantly improving the stability and heat transfer performance of boiling; (3) The micro-rib structure and the capillary porous layer are bonded by sintering technology. A convenient and efficient mold sintering processing method is adopted. The vapor-liquid two-phase separation heat exchange strengthening surface can be prepared by multiple sinterings through one processing of the mold. At the same time, the heat exchange surface has long-term stability and reliability, providing technical support for high-efficiency heat exchange devices based on the vapor-liquid two-phase separation heat exchange strengthening surface. Attached Figure Description

[0022] Figure 1 This is a perspective view of the enhanced surface structure for vapor-liquid two-phase separation heat transfer in an embodiment of the present invention;

[0023] Figure 2 This is a diagram illustrating the working mechanism of the enhanced surface structure for vapor-liquid two-phase separation heat transfer in an embodiment of the present invention.

[0024] Figure 3 This is a side sectional view of the enhanced surface structure for vapor-liquid two-phase separation heat transfer in an embodiment of the present invention;

[0025] Figure 4 This is a side sectional view of a surface structure for enhanced heat transfer in vapor-liquid two-phase separation, as described in another embodiment of the present invention.

[0026] Figure 5 This is a side sectional view of a surface structure for enhanced heat transfer in vapor-liquid two-phase separation, as described in another embodiment of the present invention.

[0027] Figure 6 The following is a side sectional view of the heat exchange enhancement surface structure for vapor-liquid two-phase separation in another embodiment of the present invention, wherein (a) is a front view of the heat exchange surface enhanced based on a non-periodic arrangement of micro-ribs, (b) is a top view of the heat exchange surface enhanced based on a non-periodic arrangement of straight ribs, (c) is a top view of the heat exchange surface enhanced based on a non-periodic arrangement of cubic ribs, and (d) is a top view of the heat exchange surface enhanced based on a non-periodic arrangement of circular ribs.

[0028] Figure 7 This is a side sectional view of a surface structure for enhanced heat transfer in vapor-liquid two-phase separation, as described in another embodiment of the present invention.

[0029] Figure 8 This is a side sectional view of a surface structure for enhanced heat transfer in vapor-liquid two-phase separation, as described in another embodiment of the present invention.

[0030] Figure 9 This is a schematic diagram of the substrate structure for machining.

[0031] Figure 10 Schematic diagram of substrate structure for sintering fabrication;

[0032] Figure 11 Schematic diagram of the substrate structure for etching fabrication;

[0033] Figure 12 A schematic diagram showing the sintered connection of the capillary porous layer and microrib structure with the concave bottom surface;

[0034] Figure 13 This is a comparison diagram of the experimental test results of the structure of this invention with other surface results;

[0035] Reference numerals: 1. Heat exchange surface substrate; 2. Microrib structure; 3. Recessed bottom surface; 4. Capillary porous layer; 5. Droplet cluster; 6. Nozzle; 7. Transport steam; 8. Spacing space; 9. Improved convex rib structure; 10. Sintered microrib structure; 11. Milling cutter; 12. Sintering mold for microrib structure; 13. Etching gas; 14. Mask; 15. Sintering mold for structure forming. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. The following embodiments are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0037] In the description of this invention, 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 only 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.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] Figure 1 A three-dimensional view of an enhanced heat transfer surface is illustrated according to an embodiment of the present invention. The enhanced heat transfer surface has a heat transfer surface substrate 1, a microrib structure 2, a recessed bottom surface 3, and a capillary porous layer 4; the enhanced heat transfer surface is combined with a droplet group 5 for heat exchange. The droplet group 5 is generated by atomization by a nozzle 6. The capillary porous layer 4 is connected to the microrib structure 2 and the recessed bottom surface 3 in a "U" shape. The connection between the capillary porous layer 4, the recessed bottom surface 3, and the microrib structure 2 constitutes a spacer space 8, which is used to realize axial transport of steam 7 during the two-phase boiling heat transfer process, reduce steam transport along the liquid phase transport direction, and alleviate the vapor-liquid transport conflict during high-intensity boiling heat transfer.

[0040] The heat exchange surface substrate has multiple microrib structures, and a recessed bottom surface is formed between adjacent microrib structures; the microrib structures are arranged in a periodic array, thereby forming a corresponding array of recessed bottom surfaces between each microrib structure.

[0041] A capillary porous layer is embedded between adjacent microrib structures and connected to the recessed bottom surface between the microrib structures. The capillary porous layer is U-shaped and connected to the microrib structures and the recessed bottom surface. The capillary porous layer is connected to the upper surface of the microrib structures, and the bottom of the U-shape of the capillary porous layer is connected to the recessed bottom surface. A space is formed between the capillary porous layer, the recessed bottom surface, and the microrib structures, serving as a steam transport channel. Furthermore, the U-shaped capillary porous layer embedded between the array of microrib structures and connected to the recessed bottom surface also constitutes a space within the array, i.e., a steam transport channel for the array.

[0042] The capillary porous layer is made of sintered multilayer metal mesh, but is not limited to multilayer metal mesh; it can also be other highly thermally conductive and hydrophilic porous materials. In this embodiment, the material of the capillary porous layer is multilayer sintered copper mesh.

[0043] The material of the heat exchange surface substrate is a metal with high thermal conductivity, such as copper or steel.

[0044] In the design of this invention, the microrib structure is a straight rib, but it is not limited to straight ribs; it can also be a square rib, a round rib, etc.

[0045] Figure 2The present invention illustrates the working mechanism of vapor-liquid two-phase separation of an enhanced heat exchange surface. When the droplet group 5 impacts the heat exchange surface and the heat flux density facing the enhanced heat exchange surface is within the range of two-phase boiling heat exchange, the droplet group 5 has two paths on the heat exchange surface: one is to be immersed in the capillary porous layer 4 covering the surface of the microrib structure 2, absorb heat and generate steam to leave the surface in the opposite direction of the droplet group's movement; the other is to be immersed in the space 8 formed by the capillary porous layer 4, the recessed bottom surface 3 and the microrib structure 2, absorb heat and generate steam to be transported in the direction perpendicular to the movement of the droplet group 5.

[0046] The vapor-liquid two-phase separation mechanism utilized in this invention can increase the critical heat flux density, i.e., the applicable heat dissipation power range of the heat exchange surface, without affecting heat exchange efficiency. In the case of spray cooling, when the heat exchange surface operates at a high heat flux density, the droplet group 5 will undergo boiling heat exchange on the heat exchange surface and generate a large amount of steam. This steam tends to escape in the opposite direction of the liquid group 5's transport, hindering the contact between the liquid group 5 and the heat exchange surface. The steam momentum will increase with the increase of the working heat flux density because the heat that the liquid needs to absorb increases accordingly, resulting in a higher steam generation rate. However, when the steam momentum is too large and causes instability in the droplet group transport, i.e., vapor-liquid transport instability, a boiling crisis will occur. The heat flux density representing this critical operating condition is the critical heat flux density, which determines the maximum operating range of the heat exchange surface. This invention introduces a non-obstructive steam transport path, i.e., along the direction perpendicular to the movement of the droplet group 5, to reduce the steam momentum along the direction that obstructs the movement of the droplet group 5, thereby delaying the instability of the droplet group transport and greatly improving the working heat flux density range.

[0047] Overall, the synergistic effect of the microrib structure 2 and the capillary porous layer 4 can significantly increase the critical heat flux density, expand the working range of the heat exchange surface, and solve the problem of vapor-liquid transport conflict in boiling heat exchange under high heat flux density.

[0048] The heat exchange surface substrate 1, the microrib structure 2, and the capillary porous layer 4 are all made of materials with high thermal conductivity. In an example of the present invention, the heat exchange surface substrate 1 and the microrib structure 2 are made of copper, with a thermal conductivity of approximately 400 W / m·K. In other examples, the heat exchange surface substrate 1 and the microrib structure 2 can be made of high thermal conductivity metals such as aluminum, steel, and iron, or cermet materials. In an example of the present invention, the capillary porous layer 4 is made of sintered multilayer copper mesh with a porosity of approximately 60% and an average pore size of approximately 80 μm. The capillary porous layer has good wettability and thermal conductivity, and its inherent contact angle is approximately 30 degrees, making it a hydrophilic layer. In various embodiments, the capillary porous layer 4 can be replaced by other materials with high wettability and thermal conductivity, such as porous membranes made of other metals.

[0049] Figure 2The invention also demonstrates the dimensional characteristics of the enhanced heat exchange surface. The vapor-liquid two-phase separation effect in this embodiment is influenced by structural dimensional characteristics and the wettability of the capillary porous layer. These dimensional characteristics include the width W1 of the space between the compartments, the width W2 of the microrib structure, and the height H1 of the space between the compartments. The wettability of the capillary porous layer is related to its contact angle and equivalent pore size, and can be quantitatively analyzed using a Laplace force calculation formula. The vapor pressure generated within the space between the compartments 8 must be less than the Laplace force maintained by moisture absorption within the capillary porous layer 4 to maintain vapor transport in the direction perpendicular to the movement of the droplet group 5. The approximate calculation of the vapor pressure within the space between the compartments is as follows: ,in For the steam pressure in the space, For the vapor viscosity within the space, To enhance the heat flux density of the heat exchange surface during operation, The heat exchange surface substrate area is the cross-sectional area of ​​the heat exchange substrate. For the vapor density in the space, The area for steam transport is related to the area of ​​the heat exchange substrate. , The latent heat of the working fluid is used for atomization cooling. The subcooling of the working fluid is used for atomization cooling. The specific heat capacity of the working fluid is used for atomization cooling. The vapor-liquid contact area can be approximated by the cross-sectional area of ​​the capillary porous layer in the space, and is related to the width W1 and height H1 of the space. Let H1 be the height of the space between the segments. The formula for calculating the Laplace force within the capillary porous layer is: ,in For Laplace force, The surface tension of the working fluid is used for atomization cooling. The contact angle of the working fluid in the capillary porous layer used for atomization cooling. The equivalent pore size of the capillary porous layer. The contact angle is an experimentally measured value; a microdroplet is placed on the surface, and after it settles, the angle formed at the gas-liquid-solid three-phase contact point is the contact angle. The design of all the above structural dimensions, including the spacing space width W1, the microrib structure width W2, the spacing space height H1, and the equivalent pore size of the capillary porous layer, must maintain within the target operating heat flux density range. Only in this way can the vapor-liquid two-phase separation mechanism be fully utilized and the transport conflict between the two phases be mitigated. The capillary porous layer is U-shaped and connected to the micro-rib structure and concave bottom surface, which effectively reduces the thermal resistance caused by the space between the phases, and maintains high heat exchange efficiency while achieving vapor-liquid two-phase separation.

[0050] Figure 3The diagram shows a front view and a top view of the heat exchange surface in an example of the present invention. The microrib structure 2 designed in this example is a straight rib structure. The straight ribs are arranged periodically, with their intervals forming a recessed bottom surface 3. A capillary porous layer 4 is connected to the straight ribs and the recessed bottom surface 3 in a "U" shape, dividing the recessed bottom surface 3 into spacer spaces 8. The microrib structure is not limited to straight ribs; it may also include cubic ribs, circular ribs, etc.

[0051] Figure 4 The diagram shows a front and top view of a heat exchange surface in another example, where the microrib structure 2 is a cubic rib structure. The cubic rib structures are arranged periodically, with their intervals forming recessed bottom surfaces 3. The capillary porous layer 4 is U-shaped and connected to the straight rib structures and recessed bottom surfaces 3, dividing each row of recessed bottom surfaces 3 into interval spaces 8.

[0052] Figure 5 The diagram shows a front and top view of a heat exchange surface in another example, where the microrib structure 2 is a circular rib structure. The circular rib structures are arranged periodically, and their intervals form a recessed bottom surface 3. The capillary porous layer 4 is connected to the straight rib structure and the recessed bottom surface 3 in a "U" shape, dividing each row of recessed bottom surfaces 3 into interval spaces 8.

[0053] Figure 6 (a) through (d) show the front and top views of the heat exchange surface in another example. The microrib structure is not limited to a periodic arrangement; the spacing between the microrib structures, the width of the recessed bottom surface, and the width of the microrib structure can be different. Figure 6 (a) is a front view of the heat transfer surface enhanced by a non-periodic arrangement of microribs. Figure 6 The middle (b) to (d) views are top views of the enhanced heat transfer surface based on the non-periodic arrangement of straight ribs, cubic ribs and circular ribs.

[0054] Figure 7 A front view of the heat exchange surface in another example is shown. The recessed bottom surface 3 structure in this invention is not limited to a plane, but can also be designed as other micro-nano structures, such as tiny straight ribs. Figure 6 In this method, tiny straight ribs with a height less than that of microrib structure 2 are fabricated on the original bottom surface, connecting the four layers of capillary porous layers in a "U" shape to microrib structure 2 and the recessed bottom surface 3. The improvement of the recessed bottom surface 3 is not limited to the aforementioned tiny straight ribs, but may also include tiny round ribs, tiny square ribs, etc. This method can further improve the stability and effectiveness of the heat exchange surface.

[0055] Figure 8 A front view of the heat exchange surface in another example is shown. The microrib structure 2 in this invention is not limited to being manufactured by machining or other methods, but can also be made into a porous microrib structure by methods such as sintering. These sintered structures can also improve heat dissipation by increasing surface nucleation sites and wettability.

[0056] The present invention also provides a method for manufacturing a vapor-liquid two-phase separation heat transfer enhancement surface, comprising the following steps:

[0057] Fabricating microrib structures: Multiple microrib structures are formed on the heat exchange surface substrate, with recessed bottom surfaces formed between adjacent microrib structures;

[0058] The capillary porous layer is connected to the surface of the microrib structure and the bottom of the depression. The space between the capillary porous layer, the bottom of the depression and the microrib structure serves as a steam transport channel.

[0059] Specifically, a capillary porous layer is embedded in a "U" shape between the microrib structure and the recessed bottom surface and then sintered and bonded. The capillary porous layer is bonded to the upper surface of the microrib structure, and the "U"-shaped bottom of the capillary porous layer is sintered and bonded to the recessed bottom surface. A space is formed between the capillary porous layer, the recessed bottom surface, and the microrib structure, and this space serves as a steam transport channel.

[0060] Optionally, the method for forming the periodic array microrib structure includes, but is not limited to:

[0061] A planar thermally conductive substrate is mechanically processed, such as by cutting or wire cutting, to form a periodic array of microrib structures;

[0062] A periodic array of microrib structures is formed on a planar thermally conductive substrate using a metal powder sintering process.

[0063] A periodic array of microrib structures is formed on a planar thermally conductive substrate using a chemical etching process.

[0064] Optionally, the capillary porous layer is made by sintering multiple layers of metal mesh, but is not limited to multiple layers of metal mesh, and may also be other highly thermally conductive and hydrophilic porous materials.

[0065] Optionally, the capillary porous layer can be connected to the microrib structure and the recessed bottom surface by sintering, but not limited to sintering; adhesive bonding or other methods can also be used.

[0066] Figures 9-11 This invention demonstrates the possible fabrication methods for the microrib structure 2, including cutting or wire-cutting the planar thermally conductive substrate using a milling cutter 11, see [link to documentation]. Figure 8 Using the designed microrib structure sintering mold 12, a microrib structure 10 is sintered from metal powder onto a planar thermally conductive substrate, as shown in [reference needed]. Figure 9 Microrib structures are chemically etched onto a planar thermally conductive substrate. A mask 14 is used to cover the non-etched areas. Etching gas 13 is used to etch the thermally conductive substrate to form a recessed bottom surface 3. (See figure) Figure 10 The processing paths for the microrib structure 2 and the recessed bottom surface 3 of the present invention include, but are not limited to, the methods described above.

[0067] Figure 12This invention demonstrates a method for connecting the capillary porous layer 3 to the microrib structure 2 and the recessed bottom surface 3. A specific structural forming sintering mold 15 needs to be designed to securely connect the capillary porous layer 3 to the microrib structure 2 and the recessed bottom surface 3. The capillary porous layer 3 completely covers the surface of the microrib structure 2 and connects to the recessed bottom surface 3 in a "U" shape. This fastener is placed in a sintering device for high-temperature bonding. After sintering, the structural forming sintering mold 15 is removed to obtain the heat exchange surface.

[0068] Figure 13 The performance comparison of the enhanced heat transfer surface of the present invention is shown. The enhanced heat transfer surface of the present invention can achieve a critical heat flux density of 1500 W / cm². 2 It is at the leading level in the research field.

[0069] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.

Claims

1. A vapor-liquid two-phase separation heat transfer enhancement surface, characterized in that, include: The heat exchange surface substrate has multiple microrib structures on its surface, and a recessed bottom surface is formed between adjacent microrib structures. A capillary porous layer is disposed on the surface of the heat exchange substrate, in contact with the surface of the microrib structure and the bottom surface of the depression. A space is formed between the capillary porous layer, the bottom surface of the depression, and the microrib structure, serving as a steam transport channel. The Laplace force maintained during the wetting process of the capillary porous layer... Steam pressure generated by steam transport within the space ,satisfy This achieves vapor-liquid two-phase separation.

2. The vapor-liquid two-phase separation heat transfer enhancement surface according to claim 1, characterized in that, The capillary porous layer is U-shaped and connected to the microrib structure and the concave bottom surface; the capillary porous layer is connected to the upper surface of the microrib structure, and the U-shaped bottom of the capillary porous layer is connected to the concave bottom surface.

3. The vapor-liquid two-phase separation heat transfer enhancement surface according to claim 1, characterized in that, The capillary porous layer is made of multilayer sintered metal mesh or other highly thermally conductive hydrophilic porous materials.

4. The vapor-liquid two-phase separation heat transfer enhancement surface according to claim 1, characterized in that, The substrate material for the heat exchange surface is a metal with high thermal conductivity.

5. The vapor-liquid two-phase separation heat transfer enhancement surface according to claim 1, characterized in that, The microrib structure can be a straight rib structure, a square rib structure, or a round rib structure.

6. The vapor-liquid two-phase separation heat transfer enhancement surface according to claim 1, characterized in that, The recessed bottom surface is also provided with microrib structures whose height is smaller than that of the microrib structure, and the capillary porous layer is in contact with the microrib structures on the recessed bottom surface.

7. The vapor-liquid two-phase separation heat transfer enhancement surface according to claim 1, characterized in that, Multiple microrib structures are arranged in a periodic array.

8. A method for manufacturing the vapor-liquid two-phase separation heat transfer enhancement surface according to any one of claims 1-7, characterized in that, Includes the following steps: Fabricating microrib structures: Multiple microrib structures are formed on the heat exchange surface substrate, with recessed bottom surfaces formed between adjacent microrib structures; The capillary porous layer is connected to the surface of the microrib structure and the bottom of the depression. The space between the capillary porous layer, the bottom of the depression and the microrib structure serves as a steam transport channel.

9. The manufacturing method according to claim 8, characterized in that, Methods for forming multiple microrib structures on a substrate surface include: Microrib structures are formed on the heat exchange surface substrate by cutting or wire cutting. A metal powder sintered microrib structure is used on a heat exchange surface substrate; Microrib structures were chemically etched onto the heat exchange surface substrate.

10. The manufacturing method according to claim 8, characterized in that, The capillary porous layer is connected to the surface and recessed bottom of the microrib structure by sintering or adhesive bonding.

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