A planar liquid-cooled heat pipe

Abstract

The present invention relates to the field of efficient heat dissipation of electronic devices, and discloses a planar liquid-cooled heat pipe, comprising: a heat pipe shell, a liquid wick, a capillary array, a cooling pipe and a porous structure; the heat pipe shell is a sealed structure, and the liquid wick is arranged in the heat pipe shell; the cooling pipe passes through both ends of the heat pipe shell and is installed on the upper side of the heat pipe shell; the porous structure is located on the lower side of the heat pipe shell; a through hole corresponding to the cooling pipe is arranged on the top of the porous structure, a capillary array and a coolant are arranged in the porous structure, the top of the capillary array passes through the porous structure, and the bottom of the capillary array is connected with the liquid wick. The planar liquid-cooled heat pipe provided by the present invention greatly increases the condensation capacity of the coolant vapor by arranging the cooling pipe and the sealing structure in the heat pipe shell, and connecting the porous structure and the liquid wick by the capillary array, and utilizing the liquid cooling technology, and at the same time, greatly increases the liquid return capacity due to the use of the capillary array, thereby effectively improving the critical heat flux density of the heat pipe.

Description

Technical Field

[0001] The invention relates to the field of efficient heat dissipation of electronic devices, and in particular to a planar liquid-cooled heat pipe. Background Art

[0002] With the development of micro-electromechanical system technology, the integration and high frequency of electronic devices are constantly improving, the characteristic size is constantly decreasing, the heat generation per unit volume is constantly increasing, and the compact design of the equipment makes heat dissipation more difficult. Therefore, it is urgent to solve the problem of efficient heat dissipation technology. Traditional air cooling and liquid convection heat transfer technology is difficult to take away a large amount of heat in time, causing the temperature of electronic devices to rise, greatly reducing their practicality and reliability. Therefore, the heat dissipation technology of high heat flux in small space has become one of the key factors restricting information, electronics, aerospace and national defense military technology.

[0003] As a phase change heat transfer method, heat pipe has significantly improved heat transfer coefficient and very small heat transfer resistance compared with traditional air cooling and liquid convection heat transfer. It can transmit a large amount of heat through a small cross-sectional area over a long distance without external power, which is a very effective heat dissipation method. However, the current critical heat flux density of heat pipes still cannot meet the heat dissipation requirements of high-end electronic devices. The main reasons for limiting the critical heat flux density of heat pipes are the cooling speed of the heat pipe condensation end, the return capacity of the capillary wick, and the steam flow resistance. The most important limiting factor is the return capacity of the capillary wick. In addition, traditional heat pipes are relatively long, and the coolant is returned entirely by the wick close to the pipe wall. Too long heat pipes further limit the return rate. When the evaporation rate of the coolant in the evaporation section is greater than the return rate of the wick, the heat pipe will enter a dry burning state, and the temperature will increase rapidly, causing the heat pipe to fail. This makes the current critical heat flux density of heat pipes still unable to meet the heat dissipation requirements of high-end electronic devices. Summary of the invention

[0004] In view of the above technical defects and application requirements, an embodiment of the present invention provides a planar liquid cooling heat pipe to overcome the defect that the critical heat flux density of a traditional heat pipe is difficult to increase due to the limited liquid return capacity of the liquid absorption core.

[0005] In order to solve the above problems, the present invention provides a planar liquid-cooled heat pipe, comprising: a heat pipe housing, a liquid wick, a capillary array, a cooling pipe and a porous structure;

[0006] The heat pipe shell is a sealed structure, and the liquid wick is arranged in the heat pipe shell; the cooling pipe passes through both ends of the heat pipe shell and is installed on the upper side of the heat pipe shell; the porous structure is located on the lower side of the heat pipe shell;

[0007] The top of the porous structure is provided with a through hole corresponding to the cooling tube, a capillary array and a coolant are provided in the porous structure, the top of the capillary array passes through the porous structure, and the bottom of the capillary array is connected to the liquid wick.

[0008] Furthermore, the outer surface of the cooling tube is provided with a super-lyophilic coating and a super-lyophobic coating.

[0009] Furthermore, the super lyophilic coating and the super lyophobic coating are distributed on the outer surface of the cooling tube in a spiral manner.

[0010] Further, the porous structure comprises: a plurality of first separators and a plurality of second separators;

[0011] The first partitions are spliced ​​with each other to separate the sealing structure into an evaporation section and a condensation section, and the first partition is provided with the through hole; the second partition is installed at the bottom of the first partition to separate the evaporation section into a plurality of evaporation units interconnected with each other.

[0012] Furthermore, the top end of the capillary array passes through the first partition plate and is connected to the first partition plate.

[0013] Furthermore, the first separator and the second separator are both porous structure separators.

[0014] Furthermore, there are a plurality of capillary arrays, and a plurality of through holes corresponding to each of the capillary arrays are provided on the top of the porous structure, and the capillary arrays are arranged around the edges of the corresponding through holes.

[0015] Furthermore, there are multiple cooling pipes, and each cooling pipe is installed on the upper side of the heat pipe housing.

[0016] Furthermore, the liquid wick is arranged along the inner wall of the heat pipe shell.

[0017] Furthermore, the heat pipe shell is a rectangular parallelepiped structure or a cylindrical structure.

[0018] The planar liquid-cooled heat pipe provided by the present invention has a cooling pipe and a sealing structure arranged in the heat pipe shell, a porous structure and a liquid wick connected by a capillary array, and utilizes liquid cooling technology to greatly increase the condensation capacity of the coolant vapor. At the same time, due to the use of the capillary array, the liquid return capacity is greatly increased, thereby effectively improving the critical heat flux density of the heat pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A schematic cross-sectional view of a planar liquid-cooled heat pipe provided in an embodiment of the present invention;

[0021] Figure 2 A top view of a planar liquid-cooled heat pipe provided by an embodiment of the present invention;

[0022] Figure 3 for Figure 1 Sectional view at the AA position;

[0023] Explanation of the reference numerals: 1. heat pipe housing; 2. liquid wick; 3. cooling tube; 4. super lyophilic coating; 5. super lyophobic coating; 6. first partition; 7. through hole; 8. capillary array; 9. cooling liquid; 10. second partition. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] The embodiment of the present invention provides a planar liquid cooling heat pipe, such as Figure 1As shown, the planar liquid-cooled heat pipe includes: a heat pipe shell 1, a liquid wick 2, a capillary array 8, a cooling pipe 3 and a porous structure. The heat pipe shell 1 is a sealed structure. The liquid wick 2 is arranged in the heat pipe shell 1, and is mainly used for the return of the coolant 9. Generally, the liquid wick 2 is arranged along the inner wall of the heat pipe shell 1. The cooling pipe 3 passes through both ends of the heat pipe shell, and the cooling pipe 3 is installed on the upper side of the heat pipe shell 1. The cooling pipe 3 is mainly used to quickly cool the steam and speed up the heat extraction. The cooling water can enter from the cooling water inlet of the cooling pipe 3 and be discharged from the cooling water outlet of the cooling pipe 3. The porous structure is located on the lower side of the heat pipe shell 1.

[0027] Among them, the top of the porous structure is provided with a through hole 7 corresponding to the cooling pipe 3, and the porous structure is provided with a capillary array 8 and a coolant 9. The heat pipe housing 1 is filled with coolant with a certain vacuum degree, and the filling rate and vacuum degree can be determined according to actual use requirements. The top of the capillary array 8 passes through the porous structure, and the bottom of the capillary array 8 is connected to the liquid wick 2.

[0028] When the planar liquid-cooled heat pipe provided in this embodiment is working normally, the bottom of the heat pipe shell 1 is tightly fitted with the heat source, absorbs heat from the heat source, and conducts the heat to the wick 2, and then transfers it to the coolant 9 immersed in the wick 2, so that the coolant 9 boils and evaporates, and the steam moves upward. Due to the obstruction of the porous structure, the steam flows into the upper space of the heat pipe shell 1 from the through hole 7 opened on the porous structure, so that the steam washes on the wall surface of the cooling tube 3, so that a large amount of steam converges on the cooling tube 3, and finally forms large droplets in the cooling tube 3 and drips on the porous structure under the action of gravity. After the dripping coolant 9 is evenly distributed by the porous structure, the coolant 9 is replenished to the wick 2 at the bottom of the heat pipe shell 1 through the capillary array 8 and the wick 2, completing the entire heat exchange cycle, and the small amount of steam that is not cooled by the cooling tube 3 will be condensed and release heat in the wick 2 at the top of the heat pipe shell 1, and then flow back to the evaporation end at the bottom of the heat pipe shell 1.

[0029] The planar liquid-cooled heat pipe provided in the embodiment of the present invention has a cooling pipe and a sealing structure arranged in the heat pipe housing, a porous structure and a liquid wick connected by a capillary array, and utilizes liquid cooling technology to greatly increase the condensation capacity of the coolant vapor. At the same time, due to the use of the capillary array, the liquid return capacity is greatly increased, thereby effectively improving the critical heat flux density of the heat pipe.

[0030] Based on the above embodiments, in a preferred embodiment, Figure 1As shown, the outer surface of the cooling tube 3 is provided with a super lyophilic coating 4 and a super lyophobic coating 5. The super lyophilic coating 4 forms a super lyophilic area on the surface of the cooling tube 3, and the super lyophobic coating 5 forms a super lyophobic area on the surface of the cooling tube 3. The super lyophilic coating 4 and the super lyophobic coating 5 are distributed in the outer surface of the cooling tube 3 at intervals. For example, when the heat pipe internal cooling liquid 9 is water, the super lyophobic area can accelerate the condensation of steam on the cooling water pipe bundle, and is a bead condensation, which plays a role in strengthening heat exchange. And the existence of the super lyophilic area is to induce the liquid droplets formed by the condensation of the super lyophobic area to move to the super lyophilic area from the super lyophobic area to converge, thereby forming larger droplets, which can drip back to the bottom of the heat pipe voluntarily under the action of gravity, realizing the rapid rehydration function.

[0031] The heat pipe housing 1 may be a rectangular parallelepiped structure or a cylindrical structure, or may be designed as required.

[0032] In this embodiment, the porous structure includes: a plurality of first baffles 6 and a plurality of second baffles 10; the first baffles 6 are spliced ​​together to separate the sealing structure into an evaporation section and a condensation section, and the first baffles 6 are provided with through holes 7. The second baffles 10 are installed at the bottom of the first baffles 6 to separate the evaporation section into a plurality of interconnected evaporation units.

[0033] In order to enhance the heat exchange capacity, the present embodiment provides a first partition 6 in the heat pipe housing 1, and a plurality of through holes 7 are provided on the first partition 6 at a position aligned with the cooling tube 3. The steam formed by the heat absorption and evaporation of the coolant 9 in the evaporation section of the sealing structure enters the condensation section of the sealing structure through the through holes 7. The presence of the first partition 6 allows the steam to flow only from the through holes 7 into the upper space, thereby increasing the steam flow rate of the through holes 7, and the relatively high-speed steam flushes the cooling tube 3 above it, thereby enhancing the heat exchange capacity of the cooling tube 3.

[0034] In order to improve the temperature uniformity of the heat pipe, the top of the capillary array 8 can be passed through the first partition 6, and the capillary array 8 can be connected to the first partition 6. The first partition 6 can be a porous structure partition to play a role in guiding liquid, and the coolant condensed and dripped on the cooling tube 3 and the coolant in the liquid wick can be ventilated laterally, so that the coolant can flow back to the evaporation section at the bottom of the heat pipe through the capillary array 8 connected to the first partition 6, which is equivalent to increasing the capillary liquid return area, thereby increasing the liquid return capacity and liquid return rate of the coolant 9. At the same time, the first partition 6 also plays the function of evenly distributing the coolant, avoiding the problem of poor local liquid return of the heat pipe, and further improving the temperature uniformity of the heat pipe.

[0035] Similarly, the second partition 10 disposed at the bottom of the first partition 6 can also be a porous partition. This can effectively alleviate the problem of excessive shaking of the coolant 9 due to shaking of the external environment, and can also play a certain role in liquid return. The second partition 10 can even be connected to the liquid wick 2 on the lower side of the heat pipe shell 1 to separate it into evaporation units. Then, holes are opened on the second partition 10 to connect the evaporation units.

[0036] Among them, since the capillary array 8 connects the first partition 6 and the liquid wick 2 at the bottom of the heat pipe shell 1, it can transport the excess coolant 9 in the porous structure and condensed by the cooling pipe 3 to the liquid wick 2 at the bottom of the heat pipe shell 1 through capillary action, replenishing the coolant 9 in the liquid wick 2 at the bottom of the heat pipe shell 1, thereby effectively increasing the return capacity of the coolant 9 and improving the critical heat flux density of the heat pipe.

[0037] In addition, to improve the heat transfer effect, such as Figure 2 As shown, the number of cooling pipes 3 can be multiple, and each cooling pipe 3 is installed on the upper side of the heat pipe housing 1. The planar liquid-cooled heat pipe is cooled by multiple cooling pipes 3, one end of which is a cooling water inlet and the other end is a cooling water outlet. The diameter of the cooling pipe 3 can be selected according to needs.

[0038] At the same time, if Figure 3 As shown, the number of capillary arrays 8 can also be set to multiple, and the top of the porous structure is provided with multiple through holes 7 corresponding to each capillary array 8, and the capillary array 8 is arranged around the edge of the through hole 7 corresponding to it. That is, the capillary array 8 is arranged around the through hole 7, and its specific density can be selected according to needs, and it should not be too dense or too sparse. An overly dense capillary array 8 will increase the flow resistance of the steam inside the heat pipe, which is not conducive to the heat exchange of the heat pipe. An overly sparse capillary array 8 will prevent the liquid return ability of the heat pipe from achieving the best effect.

[0039] When the planar liquid-cooled heat pipe provided in the present embodiment is in normal operation, the bottom of the heat pipe housing 1 is in close contact with the heat source, absorbing heat from the heat source and conducting the heat to the wick 2 in close contact with the inner wall of the heat pipe housing 1, and then transferring the heat to the coolant 9 immersed in the wick 2, so that the coolant 9 boils and evaporates, and the steam moves upward. Due to the obstruction of the first partition 6, the steam can only flow into the upper space of the heat pipe housing 1 from the plurality of through holes 7 opened on the first partition 6, so that the steam flowing through the through holes is faster. The faster steam flushes the wall of the cooling tube 3 at the upper part of the heat pipe, thereby enhancing the heat exchange performance of the cooling tube 3, so that a large amount of steam is quickly condensed into small liquid droplets in the super-lyophobic area of ​​the cooling tube 3, and many small liquid droplets gradually converge to the super-lyophilic area under the action of gravity and the attraction of the super-lyophilic area. Finally, large droplets are formed in the super-lyophilic area and drip onto the first partition 6 under the action of gravity. After the dripping coolant 9 is evenly distributed by the middle first partition 6, the coolant 9 is replenished into the wick 2 at the bottom of the heat pipe shell 1 through the capillary array 8 and the wick 2 on the walls around the heat pipe shell 1, completing the entire heat exchange cycle. A small amount of steam that is not cooled by the cooling pipe 3 will condense and release heat in the wick 2 on the top wall of the heat pipe shell 1, and then flow back to the evaporation end at the bottom of the heat pipe shell 1 through the wick 2 on the walls around the heat pipe shell 1. Due to the use of liquid cooling technology, the condensation capacity of the coolant 9 vapor is greatly increased. At the same time, due to the use of the capillary array 8, the liquid return capacity is greatly increased, thereby effectively improving the critical heat flux density of the heat pipe.

[0040] In summary, the planar liquid-cooled heat pipe provided in the embodiment of the present invention has a cooling pipe and a sealing structure arranged in the heat pipe shell, a porous structure and a liquid wick connected by a capillary array, and utilizes liquid cooling technology to greatly increase the condensation capacity of the coolant vapor. At the same time, due to the use of the capillary array, the liquid return capacity is greatly increased, thereby effectively improving the critical heat flux density of the heat pipe.

[0041] In addition, it should be noted that the planar liquid-cooled heat pipe provided in this embodiment is suitable for heat exchange with horizontally arranged heat sources. For inclined or vertically arranged heat sources, the heat pipe structure can be changed accordingly as needed.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the invention rather than to limit it. Although the invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the invention.

Claims

1. A planar liquid-cooled heat pipe, characterized in that: include: Heat pipe housings, wicks, capillary arrays, cooling tubes, and porous structures; The heat pipe housing is a sealed structure, and the liquid wick is arranged in the heat pipe housing; The cooling pipe passes through both ends of the heat pipe shell and is installed on the upper side of the heat pipe shell; the porous structure is located on the lower side of the heat pipe shell; The top of the porous structure is provided with a through hole corresponding to the cooling pipe, the capillary array and the coolant are arranged in the porous structure, the top of the capillary array passes through the porous structure, and the bottom of the capillary array is connected with the wick; the bottom of the heat pipe shell is used to fit closely with the heat source and conduct heat to the wick, and then transfer it to the coolant immersed in the wick, so that the coolant boils and evaporates, and the steam flows into the upper space of the heat pipe shell from the through hole opened on the porous structure, and the steam flushes on the wall surface of the cooling pipe, so that a large amount of steam converges in the cooling pipe, and finally forms large droplets in the cooling pipe and drips on the porous structure under the action of gravity, and after the dripping coolant is evenly distributed by the porous structure, the coolant is replenished to the wick at the bottom of the heat pipe shell through the capillary array and the wick; the outer surface of the cooling pipe is provided with a super-liquid-philic coating and a super-liquid-repellent coating, and the wick is arranged along the inner wall of the heat pipe shell.

2. The planar liquid-cooled heat pipe according to claim 1, characterized in that: The super lyophilic coating and the super lyophobic coating are distributed on the outer surface of the cooling tube in a spiral interval.

3. The planar liquid-cooled heat pipe according to claim 1, characterized in that: The porous structure includes: a plurality of first separators and a plurality of second separators; The first partitions are spliced ​​with each other to separate the sealing structure into an evaporation section and a condensation section, and the first partition is provided with the through hole; the second partition is installed at the bottom of the first partition to separate the evaporation section into a plurality of evaporation units interconnected with each other.

4. The planar liquid-cooled heat pipe according to claim 3, characterized in that: The top end of the capillary array passes through the first partition and is connected to the first partition.

5. The planar liquid-cooled heat pipe according to claim 3, characterized in that: The first separator and the second separator are both separators with porous structures.

6. The planar liquid-cooled heat pipe according to claim 1, characterized in that: There are multiple capillary arrays, and the top of the porous structure is provided with multiple through holes corresponding to each of the capillary arrays. The capillary arrays are arranged around the edges of the corresponding through holes.

7. The planar liquid-cooled heat pipe according to claim 1, characterized in that: There are multiple cooling pipes, and each cooling pipe is installed on the upper side of the heat pipe housing.

8. The planar liquid-cooled heat pipe according to any one of claims 1 to 7, characterized in that: The heat pipe shell is a rectangular parallelepiped structure or a cylindrical structure.

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