A heat-mass synergistic high-efficiency transmission reinforced heat transfer device

Abstract

The application discloses a kind of reinforced heat transfer devices of heat mass synergic high-efficiency transmission, belong to phase change heat transfer technical field;The device includes condensing cover plate, the bottom of the condensing cover plate is sealed to connect evaporating cover plate, the inner side of the condensing cover plate is equipped with hydrophilic / hydrophobic combined surface, the condensing cover plate and evaporating cover plate are sequentially equipped with sidewall wick, auxiliary reflux zone wick from top to bottom between the condensing cover plate and evaporating cover plate, the auxiliary reflux zone wick is equipped with capillary reflux column and is inserted, the center of the auxiliary reflux zone wick is equipped with central boiling zone wick.The device makes hydrophilic pattern gather liquid and then returns auxiliary reflux zone wick through capillary reflux column, and then quickly returns central boiling zone wick under the action of gradient capillary force, through the synergic design of condensing end hydrophilic / hydrophobic combined surface and reflux path, the structure of wick is optimized, the working medium is quickly refluxed and bubble is efficiently overflowed, and the heat transfer performance and operating stability of the device are improved.

Description

Technical Field

[0001] This invention relates to the field of phase change heat transfer technology, and in particular to an enhanced heat transfer device for efficient heat and mass transfer, specifically a heat spreader with a flow guiding structure. Background Technology

[0002] With the rapid development of electronic information technology towards higher integration and higher power density, the heat flux density generated by electronic devices during operation has increased dramatically. Traditional heat dissipation methods such as air cooling and conventional heat pipes can no longer meet the requirements for efficient heat dissipation. Phase change heat transfer elements, represented by heat spreaders, achieve rapid temperature equalization and efficient heat dissipation through the internal phase change cycle of the working fluid, becoming the core heat dissipation solution in high heat flux density scenarios.

[0003] However, the following technical problems still exist in the practical application of such plate-type phase change heat transfer elements: First, the condensation surfaces of existing phase change heat transfer elements are mostly single hydrophilic or single hydrophobic structures, and condensate droplets tend to accumulate locally and spread disorderly in the condensation area, making it difficult to achieve rapid and directional transport. Secondly, existing phase change heat transfer elements lack a dedicated liquid flow collection and directional reflux structure, so the condensate cannot efficiently and quickly reflux from the condensation zone to the evaporation and boiling zone, resulting in a low working fluid circulation rate. Third, the evaporation zone has a simple liquid absorption core structure, and the overflow of bubbles and the return of liquid are prone to conflict, resulting in a decrease in heat exchange performance and insufficient operational stability.

[0004] Fourth, the existing phase change heat transfer elements have three functional sections—condensation, reflux, and evaporation—that are mostly designed independently, lacking a heat-mass synergy mechanism, making it difficult to achieve efficient transfer. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an enhanced heat transfer device for efficient heat and mass transfer. Specifically, it is a heat spreader with a flow guiding structure. By coordinating the design of the hydrophilic / hydrophobic surface of the condenser end and the return path, and optimizing the liquid wick structure, it achieves rapid return of the working fluid and efficient overflow of bubbles, significantly improving heat dissipation performance and operational stability.

[0006] To achieve the above objectives, the present invention provides an enhanced heat transfer device for efficient heat and mass transfer, comprising a heat spreader body, the heat spreader body including a condenser cover plate, the bottom of the condenser cover plate being sealed to an evaporator cover plate, the inner side of the condenser cover plate having a hydrophilic / hydrophobic bonding surface, and a sidewall liquid absorption core and an auxiliary reflux zone liquid absorption core arranged sequentially from top to bottom between the condenser cover plate and the evaporator cover plate, the auxiliary reflux zone liquid absorption core having a capillary reflux column inserted therethrough, and a central boiling zone liquid absorption core being provided at the center of the auxiliary reflux zone liquid absorption core.

[0007] In this invention, the "efficient heat and mass transfer" refers to: the hydrophobic surface at the condenser end promotes efficient droplet condensation of steam (heat), while the hydrophilic pattern directionally captures and transports the condensate droplets (mass); the condensate is rapidly guided to the wicking core of the auxiliary reflux zone at the evaporator end via a capillary reflux column in direct contact with the hydrophilic pattern (mass); the gradient aperture wicking core structure at the evaporator end generates a capillary driving force pointing towards the central boiling zone, rapidly replenishing the boiling zone with reflux liquid (mass), while the gaps between the capillary microcolumns provide an unobstructed overflow channel for boiling bubbles (heat). Thus, the heat and mass transfer processes of condensation, reflux, and evaporation are organically integrated into a synergistically enhanced closed-loop system.

[0008] Preferably, the inner edge of the condenser cover is provided with a barrier groove, and the edge of the evaporator cover is provided with a barrier protrusion, the barrier groove and the barrier protrusion matching each other; the outer side of the barrier groove is provided with a condenser cover sealing section, and the outer side of the barrier protrusion is provided with an evaporator cover sealing section, the positions of the condenser cover sealing section and the evaporator cover sealing section corresponding to each other.

[0009] Preferably, the side wall of the evaporator cover is provided with a filling pipe. The evaporator cover and the sealing section of the condenser cover, as well as the evaporator cover and the filling pipe, are all sealed together by low-temperature vacuum brazing and form a closed steam chamber. A brazing layer is formed between the sealing sections of the evaporator cover and the condenser cover. A non-sealed long-path overflow barrier structure is formed between the barrier groove and the barrier boss to prevent the brazing filler metal from seeping into the steam chamber. The steam chamber is evacuated to an absolute pressure of less than 1 Pa. Working fluid, which is deionized water, is introduced into the filling pipe. The filling rate of the working fluid in the steam chamber is 25% to 35%.

[0010] Preferably, the hydrophilic / hydrophobic bonding surface includes a hydrophilic pattern and a hydrophobic substrate. The hydrophilic pattern array is disposed inside the barrier groove. The hydrophilic pattern includes a wedge-shaped flow channel and a circular liquid reservoir. The wedge-shaped flow channel is used to directionally capture and rapidly transport condensate droplets to the circular liquid reservoir.

[0011] Preferably, the wedge-shaped flow channel gradually expands along the liquid flow direction, and the wedge-shaped angle formed by the two side walls of the wedge-shaped flow channel... α The angle is 5°~30°; the static contact angle of the hydrophilic pattern is <5°, the static contact angle of the hydrophobic substrate is >160°, and the roll-off angle is <5°.

[0012] Preferably, the hydrophilic / hydrophobic bonding surface is prepared by the following steps: S1. The condenser cover plate is subjected to hydrophilic treatment, and then treated with fluorosilane solution to form an overall hydrophobic surface; S2. The hydrophobic coating in a designated area is removed by laser engraving on a homogeneous hydrophobic surface to form a preset hydrophilic pattern. A hydrophilic treatment solution is then injected into the engraved area to form a hydrophilic surface, ultimately resulting in a hydrophilic / hydrophobic combined surface. The hydrophilic treatment solution comprises an alkaline solution and a potassium persulfate solution.

[0013] Preferably, one end of the capillary reflux column is in direct contact with the circular liquid storage tank inside the condensation cover plate, and the other end is in direct contact with the evaporation cover plate. The condensate droplets collected in the circular liquid storage tank are quickly refluxed back to the liquid suction core in the auxiliary reflux zone through the capillary reflux column. With the optimized liquid suction core structure, efficient circulation of the working fluid and smooth overflow of bubbles are achieved, which significantly improves the reflux efficiency and heat exchange performance of the heat spreader. The wedge-shaped flow channel and the circular liquid storage tank are both formed by laser engraving, with an engraving depth of 40~100μm.

[0014] Preferably, the central boiling zone absorbing core includes a base absorbing core and capillary micro-columns. The base absorbing core is made of copper powder sintered at high temperature, and the average pore size of the base absorbing core is smaller than the average pore size of the auxiliary reflux zone absorbing core.

[0015] Preferably, the height of the liquid-absorbing core in the central boiling zone is the same as the height of the liquid-absorbing core in the auxiliary reflux zone, and gaps are provided between the capillary micro-columns to allow boiling bubbles to overflow.

[0016] Preferably, the central boiling zone suction core, capillary reflux column, auxiliary reflux zone suction core, and sidewall suction core are all hydrophilically treated to possess hydrophilic properties.

[0017] Therefore, the present invention employs the above-mentioned enhanced heat transfer device for efficient heat and mass transfer, and the technical effects are as follows: The condenser end of this device employs a surface design combining a hydrophobic substrate and a hydrophilic pattern. The hydrophobic surface promotes efficient droplet condensation of vapor, while the hydrophilic pattern directionally captures and rapidly transports the condensate droplets to a circular storage tank. The storage tank is directly connected to the auxiliary reflux zone wick at the evaporator end via capillary reflux columns, forming a continuous working fluid pathway of "condensation-capture-guidance-reflux". The evaporator end features a gradient aperture wick structure from the outer edge to the center. The average pore size of the substrate wick is smaller than that of the auxiliary reflux zone wick, generating capillary suction force directed towards the central boiling zone, accelerating liquid replenishment. Large gaps exist between the capillary micro-columns in the central boiling zone, providing an unobstructed overflow channel for boiling bubbles, mitigating or avoiding the conflicting effects of "bubble overflow - liquid reflux". This structure organically integrates the heat and mass transfer processes of condensation, reflux, and evaporation, achieving efficient and coordinated heat and mass transfer, significantly improving the device's heat transfer performance and operational stability.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0019] Figure 1 This is an exploded schematic diagram of an embodiment of an enhanced heat transfer device for efficient heat and mass transfer according to the present invention. Figure 2 yes Figure 1 A schematic diagram of the hydrophilic-hydrophobic composite surface of the condenser cover plate of the device shown; Figure 3 yes Figure 2 A schematic diagram of droplet transport in a hydrophilic pattern; Figure 4 yes Figure 1 A schematic diagram of the synergistic enhancement of condensate reflux by the "hydrophilic-hydrophobic composite surface-capillary reflux column" in the device shown; Figure 5 yes Figure 1 A schematic diagram of the reflux of the condensate in the apparatus shown. Figure 6 yes Figure 1 A schematic diagram of the liquid suction core in the central boiling zone of the device shown.

[0020] Figure Labels 1. Condensation cover; 10. Barrier groove; 11. Hydrophilic pattern; 111. Wedge-shaped flow channel; 112. Circular liquid reservoir; 12. Hydrophobic substrate; 13. Condensation cover sealing section; 2. Evaporator cover plate; 20. Barrier boss; 21. Evaporator cover plate sealing section; 3. Capillary reflux column; 4. Sidewall suction core; 5. Central boiling zone suction core; 50. Base suction core; 51. Capillary microcolumn; 6. Auxiliary reflux zone suction core; 7. Filling tube; 8. Vapor chamber; 9. Condensate droplets; 14. Capillary driven liquid film; 15. Brazing layer. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0023] Example 1 This embodiment provides an enhanced heat transfer device for efficient heat and mass transfer, specifically a heat spreader with a flow guiding structure. For example... Figure 1 As shown, the heat spreader includes a condensation cover plate 1, an evaporation cover plate 2, a capillary reflux column 3, a side wall liquid suction core 4, a central boiling zone liquid suction core 5, an auxiliary reflux zone liquid suction core 6, and a filling pipe 7.

[0024] The condenser cover 1, evaporator cover 2, and filling tube 7 are all made of copper; the capillary reflux column 3, side wall suction core 4, and auxiliary reflux zone suction core 6 are all made of foamed copper; Figure 6 As shown, the central boiling zone absorbing core 5 includes a base absorbing core 50 and capillary micropillars 51, which are integrally sintered from copper powder. The capillary micropillars 51 are located above the base absorbing core 50, and their heights each account for half the height of the central boiling zone absorbing core 5. Before assembly, all components are sequentially cleaned with anhydrous ethanol, dilute hydrochloric acid, deionized water, and anhydrous ethanol to remove the surface oxide layer and oil stains.

[0025] The central boiling zone liquid-absorbing core 5 is formed by sintering copper powder particles with a particle size of 20~150μm under an inert atmosphere. During sintering, the copper powder is loaded into a graphite mold, compacted by vibration, and then placed in a crucible furnace. The furnace is heated to 970℃ in stages under a slightly positive argon atmosphere and held at that temperature. Subsequently, it is cooled with the furnace to obtain a sintered liquid-absorbing core structure with uniform pores.

[0026] The capillary reflux column 3, the side wall wick 4, the auxiliary reflux zone wick 6, and the central boiling zone wick 5 are tightly bonded to the evaporation cover plate 2 by coating with copper solder paste and sintering at high temperature, forming an integrated evaporation end structure. During assembly, each wick and the capillary reflux column 3 are positioned sequentially, and pressure is applied by a pressure block before sintering and fixing under argon protection.

[0027] In this embodiment, the capillary reflux column 3, the sidewall suction core 4, and the auxiliary reflux zone suction core 6 are made of foamed copper with an average pore size of 169~231μm; the average pore size of the base suction core 50 is smaller than that of the auxiliary reflux zone suction core 6; the height of the central boiling zone suction core 5 is the same as that of the auxiliary reflux zone suction core 6; gaps are provided between the capillary micro-columns 51 for boiling bubbles to overflow, thereby forming a pore size gradient from the edge to the center, so as to generate a capillary driving force pointing towards the central boiling zone suction core 5, and enhance the working fluid replenishment effect.

[0028] To improve capillary performance, the integrated evaporation end structure is immersed in an alkaline oxidation mixed solution for oxidation treatment, which forms a micro-nano composite structure on the surface of each liquid absorption core, enhancing hydrophilicity and capillary suction capability.

[0029] like Figure 2 , Figure 3As shown, the inner wall of the condenser cover 1 is provided with a hydrophilic / hydrophobic bonding surface, the pattern of which matches the projection of the inner cavity of the evaporator cover 2. The hydrophilic / hydrophobic bonding surface includes a hydrophilic pattern 11 and a hydrophobic substrate 12. The hydrophilic pattern 11 is arrayed inside the barrier groove 10. The hydrophilic pattern 11 includes a wedge-shaped flow channel 111 and a circular liquid reservoir 112. The wedge-shaped flow channel 111 contains a capillary-driven liquid film 14, which is used to directionally capture and rapidly transport condensate droplets 9 to the circular liquid reservoir 112. The wedge-shaped flow channel 111 gradually expands along the liquid flow direction, with an included angle α of 5°~30°, which can directionally transport condensate droplets 9. The circular liquid reservoir 112 is in corresponding contact with the top of the capillary reflux column 3, so that the condensate can be rapidly returned to the evaporation end through the capillary reflux column 3. The wedge-shaped flow channel 111 and the circular liquid reservoir 112 are both laser-engraved, with an engraving depth of 40~100μm.

[0030] The preparation process of the hydrophilic / hydrophobic composite surface is as follows: First, the condenser cover plate 1 is subjected to overall superhydrophilic treatment, and then modified with fluorosilane to obtain an overall superhydrophobic surface; the hydrophobic coating in a designated area is removed by laser engraving, with an engraving depth of 40~100μm, and then the engraved area is subjected to local hydrophilic treatment, finally forming a hydrophilic / hydrophobic partition structure. Among them, the static contact angle of the hydrophilic area is <5°, the static contact angle of the hydrophobic area is >160°, and the roll-off angle is <5°.

[0031] After polishing, the condenser cover sealing section 13 of the condenser cover plate 1 and the evaporator cover sealing section 21 of the evaporator cover plate 2 are vacuum brazed using indium-based brazing filler metal at a low temperature of 160℃~180℃ to prevent heat deformation of the internal capillary structure and ensure reliable cavity sealing. The heat spreader uses deionized water as the working fluid, which is filled through the filling pipe 7 at a filling rate of 25%~35%. After filling, the filling pipe 7 is sealed using a combination of cold welding and argon arc welding to ensure the long-term airtightness of the steam chamber 8.

[0032] like Figure 1 , Figure 2 , Figure 5 As shown, the inner edge of the condenser cover plate 1 is provided with a barrier groove 10, and the edge of the evaporator cover plate 2 is provided with a barrier protrusion 20. The barrier groove 10 and the barrier protrusion 20 are matched.

[0033] The side wall of the evaporation cover plate 2 is provided with a filling pipe 7. The evaporation cover plate 2 and the filling pipe 7 are sealed together by low temperature vacuum brazing and together with the condensation cover plate 1 to form a closed steam chamber 8. The barrier groove 10 and the barrier protrusion 20 form a non-sealed long-path overflow barrier structure to prevent the brazing filler metal from seeping into the steam chamber. The inside of the steam chamber is evacuated to an absolute pressure of less than 1 Pa to effectively remove the non-condensable gases inside, thereby maintaining the low-pressure environment required for efficient phase change.

[0034] like Figure 3 , Figure 4As shown, one end of the capillary reflux column 3 is in direct contact with the circular liquid storage tank 112 inside the condensation cover plate 1, and the other end is in direct contact with the evaporation cover plate 2. The condensate droplets 9 collected in the circular liquid storage tank 112 are quickly refluxed back to the liquid suction core 6 in the auxiliary reflux zone through the capillary reflux column 3. With the optimized liquid suction core structure, the working fluid is circulated efficiently and the bubbles overflow smoothly, which significantly improves the reflux efficiency and heat exchange performance of the heat spreader. During operation, the working fluid is heated and vaporized in the central boiling zone suction core 5, and the vapor condenses into droplets in the condenser cover plate 1. The droplets are collected in the circular storage tank 112 through the wedge-shaped flow channel 111, and then quickly returned to the auxiliary return zone suction core 6 through the capillary return column 3. Under the capillary driving force formed by the pore size gradient, it is efficiently returned to the central boiling zone suction core 5, realizing efficient circulation of the working fluid and high heat flux density heat dissipation.

[0035] Therefore, the present invention employs the above-mentioned enhanced heat transfer device with efficient heat and mass transfer, which achieves rapid recirculation of the working fluid and efficient overflow of bubbles by coordinating the design of the hydrophilic / hydrophobic combined surface of the condenser end and the return path, and optimizing the liquid wick structure, thereby significantly improving heat dissipation performance and operational stability.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A heat transfer enhancement device for efficient heat and mass transfer, characterized in that, The device includes a heat spreader body, which includes a condenser cover plate. The bottom of the condenser cover plate is sealed to an evaporator cover plate. The inner side of the condenser cover plate is provided with a hydrophilic / hydrophobic bonding surface. From top to bottom, a sidewall liquid absorption core and an auxiliary reflux zone liquid absorption core are provided between the condenser cover plate and the evaporator cover plate. A capillary reflux column is inserted through the auxiliary reflux zone liquid absorption core. A central boiling zone liquid absorption core is provided at the center of the auxiliary reflux zone liquid absorption core.

2. The enhanced heat transfer device for efficient heat and mass transfer according to claim 1, characterized in that: The inner edge of the condenser cover is provided with a barrier groove, and the edge of the evaporator cover is provided with a barrier protrusion. The barrier groove and the barrier protrusion are matched. The outer side of the barrier groove is provided with a condenser cover sealing section, and the outer side of the barrier protrusion is provided with an evaporator cover sealing section. The positions of the condenser cover sealing section and the evaporator cover sealing section are corresponding.

3. The enhanced heat transfer device for efficient heat and mass transfer according to claim 2, characterized in that: The side wall of the evaporation cover is provided with a filling pipe. The evaporation cover and the filling pipe, as well as the sealing section of the evaporation cover and the condensation cover, are all sealed and connected by low-temperature vacuum brazing, and together they enclose a closed steam chamber. A brazing layer is formed between the sealing section of the evaporation cover and the condensation cover, and a non-sealed long-path overflow barrier structure is formed between the barrier groove and the barrier boss. Working fluid, which is deionized water, is introduced into the filling pipe, and the filling rate of the working fluid in the steam chamber is 25%~35%.

4. The enhanced heat transfer device for efficient heat and mass transfer according to claim 3, characterized in that: The hydrophilic / hydrophobic bonding surface includes a hydrophilic pattern and a hydrophobic substrate. The hydrophilic pattern array is disposed inside the barrier groove. The hydrophilic pattern includes a wedge-shaped flow channel and a circular liquid reservoir. The wedge-shaped flow channel is used to directionally capture and rapidly transport condensate droplets to the circular liquid reservoir.

5. The enhanced heat transfer device for efficient heat and mass transfer according to claim 4, characterized in that: The wedge-shaped flow channel gradually expands along the direction of liquid flow, and the wedge-shaped angle formed by the two side walls of the wedge-shaped flow channel... α The range is 5° to 30°.

6. The enhanced heat transfer device for efficient heat and mass transfer according to claim 5, characterized in that: The hydrophilic / hydrophobic bonding surface is prepared by the following steps: S1. The condenser cover plate is subjected to hydrophilic treatment, and then treated with fluorosilane solution to form an overall hydrophobic surface; S2. The hydrophobic coating in a designated area is removed by laser engraving on a homogeneous hydrophobic surface to form a preset hydrophilic pattern, and a hydrophilic treatment solution is injected into the engraved area to form a hydrophilic surface, finally obtaining a hydrophilic / hydrophobic combined surface.

7. The enhanced heat transfer device for efficient heat and mass transfer according to claim 6, characterized in that: One end of the capillary reflux column is in direct contact with the circular liquid storage tank inside the condensation cover plate, and the other end is in direct contact with the evaporation cover plate. The condensate droplets collected in the circular liquid storage tank are rapidly refluxed back to the liquid suction core in the auxiliary reflux zone through the capillary reflux column.

8. The enhanced heat transfer device for efficient heat and mass transfer according to claim 1, characterized in that: The central boiling zone absorbing core includes a base absorbing core and capillary micro-columns. The base absorbing core is made of copper powder sintered at high temperature, and the average pore size of the base absorbing core is smaller than the average pore size of the auxiliary reflux zone absorbing core.

9. The enhanced heat transfer device for efficient heat and mass transfer according to claim 8, characterized in that: The height of the liquid suction core in the central boiling zone is the same as the height of the liquid suction core in the auxiliary reflux zone, and gaps are provided between the capillary micro-columns to allow boiling bubbles to overflow.

10. The enhanced heat transfer device for efficient heat and mass transfer according to claim 9, characterized in that: The central boiling zone suction core, capillary reflux column, auxiliary reflux zone suction core, and sidewall suction core are all hydrophilic treated to acquire hydrophilic properties.

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