A loop heat pipe heat dissipation device and preparation method thereof

Abstract

The present invention discloses a loop heat pipe heat dissipation device, comprising: an evaporator, a condenser, a steam pipeline and a liquid pipeline, the evaporator comprising a bottom plate, a liquid wick structure, a cover plate and a sealing structure, the cover plate is arranged on the bottom plate, the bottom plate and the cover plate form a vacuum cavity, the liquid wick structure is arranged in the vacuum cavity, the liquid wick structure is used to store liquid heat transfer medium, the liquid wick structure is used to cooperate with the cover plate to separate the vacuum cavity into a compensation cavity and an evaporation chamber arranged at intervals, the sealing structure is arranged at one end of the cover plate close to the bottom plate, and the position of the sealing structure corresponds to the position of the liquid wick structure, and the end of the sealing structure away from the cover plate is used to abut against the liquid wick structure to achieve isolation of the compensation cavity and the evaporation chamber. The heat dissipation device of the present application improves the gas-liquid isolation performance in the evaporator, solves the problem of gas leakage and heat leakage from the evaporation chamber to the compensation cavity, and thus improves the heat dissipation performance.

Description

Technical Field

[0001] The present invention relates to the technical field of phase change heat dissipation, and in particular to a loop heat pipe heat dissipation device and a preparation method thereof. Background Art

[0002] In recent years, with the rapid development of electronic technology, the power of electronic devices has continued to increase, and the problem of chip heating has become increasingly prominent. Traditional loop heat pipes can no longer meet the heat dissipation needs of high-power electronic devices.

[0003] The loop heat pipe is a passive phase change heat transfer device, which consists of four parts: evaporator, condenser, steam pipeline and liquid pipeline. The capillary force generated by the porous wick in the evaporator is the driving source. The liquid in the wick absorbs heat and evaporates, and enters the condenser through the steam pipeline to release heat and become supercooled liquid. The supercooled liquid returns to the compensation cavity through the liquid pipeline under the action of capillary force to achieve heat transfer. The loop heat pipe has the advantages of high reliability, long heat transfer distance, large heat transfer capacity, and flexible layout. It has great application prospects in the field of thermal management of high-power electronic equipment.

[0004] However, the evaporator of a traditional flat-plate loop heat pipe generally adopts a vertically arranged structure of a compensation cavity, a liquid wick and a steam channel. Under high power, the steam superheat is large, the heat taken away by the evaporation chamber is limited, and the heat leakage problem is serious, which limits the ultimate heat dissipation performance of the loop heat pipe and may cause instability problems such as startup pulses, temperature fluctuations and even startup failures. There is also a risk of dry burning of the loop heat pipe. Summary of the invention

[0005] Based on this, it is necessary to provide a loop heat pipe heat dissipation device that can reduce heat leakage and dissipate heat reliably.

[0006] A loop heat pipe heat dissipation device, the loop heat pipe heat dissipation device comprising:

[0007] An evaporator, the evaporator comprising a base plate, a wick structure, a cover plate and a sealing structure, the cover plate being arranged on the base plate, the base plate and the cover plate forming a vacuum cavity, the wick structure being arranged in the vacuum cavity, the wick structure being used to store a liquid heat transfer medium, the wick structure being used to cooperate with the cover plate to separate the vacuum cavity into a compensation cavity and an evaporation chamber which are arranged at intervals, the sealing structure being arranged at one end of the cover plate close to the base plate, and the position of the sealing structure corresponds to the position of the wick structure, and the end of the sealing structure away from the cover plate is used to abut against the wick structure to achieve gas-liquid separation between the compensation cavity and the evaporation chamber;

[0008] A condenser is vertically arranged above the evaporator, and the condenser is connected to the evaporator;

[0009] a steam pipeline, one end of which is connected to the evaporation chamber and the other end of which is connected to the condenser; and

[0010] A liquid pipeline has one end connected to the compensation chamber and the other end connected to the condenser.

[0011] Optionally, the liquid absorbent core structure includes a first liquid absorbent core and a second liquid absorbent core, the first liquid absorbent core is arranged at one end of the bottom plate close to the cover plate, the first liquid absorbent core is used to cooperate with the cover plate to separate the vacuum chamber into a compensation chamber and an evaporation chamber, the first liquid absorbent core is also used to store the liquid heat transfer medium, the second liquid absorbent core is located below the first liquid absorbent core, the second liquid absorbent core is arranged in the evaporation chamber, the thermal conductivity of the second liquid absorbent core is greater than the thermal conductivity of the first liquid absorbent core, the second liquid absorbent core is used to supply the liquid heat transfer medium to be heated and phase-changed into a gaseous heat transfer medium, the position of the sealing structure corresponds to the position of the first liquid absorbent core, and the sealing structure is used to abut against the first liquid absorbent core.

[0012] Optionally, the first liquid absorbent core includes a main body and two matching parts, the two matching parts are relatively arranged at two ends of the main body, and a first end face is provided at one end of the matching part away from the main body. The evaporator also includes two blocking parts, the two blocking parts are relatively arranged at two ends of the cover plate, the blocking part includes a blocking plate and a docking part, one end of the blocking plate is connected to the inner side wall of the cover plate, and the other end of the blocking plate is connected to the docking part, the blocking part is used to abut against the top surface of the bottom plate, and the docking part is provided with a second end face, the first end face and the second end face are both inclined surfaces, and the second end face and the first end face are complementary angles to each other, and the second end face is used to dock with the first end face, and the first liquid absorbent core is used to cooperate with the blocking plate and the docking part, so that when the cover plate and the bottom plate are docked, the gas-liquid separation of the compensation cavity and the evaporation chamber is realized.

[0013] Optionally, the first liquid absorbent core further includes a support portion, wherein the support portions are arranged at intervals on the same side of the main body along the length direction of the main body, and the support portions are used to divide the evaporation chamber into steam flow channels arranged at intervals.

[0014] Optionally, the evaporator further comprises a boss, wherein the boss is arranged at an end of the bottom plate away from the cover plate, and the position of the boss corresponds to the position of the second liquid wick.

[0015] Optionally, the evaporator also includes a liquid flow channel, which is arranged in the cover plate and is circumferentially arranged around the compensation chamber. The liquid flow channel is connected to the compensation chamber, and one end of the liquid flow channel is connected to the liquid pipeline. The liquid flow channel is used to transport the liquid heat transfer medium into the compensation chamber.

[0016] Optionally, a plurality of liquid separation ports are provided on the liquid flow channel, and the plurality of liquid separation ports are arranged at intervals, and the liquid separation ports are used to allow the heat transfer medium in the liquid separation pipeline to flow out into the compensation chamber.

[0017] Optionally, the condenser includes a condensation pipeline and fins, one end of the condensation pipeline is connected to the steam pipeline, the other end of the condensation pipeline is connected to the liquid pipeline, and the fins are arranged around the condensation pipeline.

[0018] Optionally, the height of the condensation pipeline gradually decreases from one end connected to the steam pipeline to another end connected to the condensation pipeline.

[0019] A method for preparing the above-mentioned loop heat pipe heat dissipation device comprises the following steps:

[0020] Processing and manufacturing cover plates, bottom plates, liquid pipelines and steam pipelines;

[0021] Bending to form a condensing pipe, making fins, and assembling the condensing pipe and the fins to obtain a condenser;

[0022] The liquid wick structure is prepared by using a metal powder sintering process;

[0023] The performance of the wick structure is improved by using an electrodeposition process;

[0024] The wick structure is arranged between the bottom plate and the cover plate, so that the sealing structure arranged in the cover plate abuts against the top surface of the wick structure, the bottom of the wick structure fits with the top surface of the bottom plate, and the wick structure divides the vacuum cavity formed by the cover plate and the bottom plate into a compensation cavity and an evaporation chamber arranged at intervals, and then the bottom plate and the cover plate are sealed and connected;

[0025] The steam pipeline is sealed and connected to the evaporator and condenser respectively, and the liquid pipeline is sealed and connected to the evaporator and condenser respectively.

[0026] The loop heat pipe heat dissipation device provided by the present application forms a coplanar structure with the compensation chamber and the evaporation chamber by changing the liquid wick structure, and a sealing structure is also provided on the cover plate, and the cover plate and the top of the liquid wick structure are tightly connected through the sealing structure, so that the steam in the evaporation chamber is difficult to be transmitted from the gap between the top of the liquid wick structure and the cover plate to the compensation chamber, so that the steam in the evaporation chamber can be basically transmitted to the condenser through the steam pipeline, which improves the gas-liquid isolation performance in the evaporator, solves the problem of gas leakage and heat leakage from the evaporation chamber to the compensation chamber, and thus improves the heat dissipation performance. In addition, the present application also maximizes the use of the longitudinal space inside the server by vertically arranging the condenser above the evaporator, which can reduce the floor space occupied by the present application in the horizontal space, and the condenser is vertically arranged above the evaporator, which can use gravity to realize the reflux of the liquid heat transfer medium in the condenser, reduce the pressure loss of the gaseous heat transfer medium in the condenser, and thus improve the overall circulation driving force. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0028] Figure 1 A schematic diagram of the structure of a loop heat pipe heat dissipation device in one embodiment;

[0029] Figure 2 A schematic structural diagram of a liquid wick structure of a loop heat pipe heat dissipation device in one embodiment;

[0030] Figure 3 A schematic diagram of the structure of a boss of a loop heat pipe heat dissipation device in one embodiment;

[0031] Figure 4 A schematic diagram of the structure of an evaporator of a loop heat pipe heat dissipation device in one embodiment;

[0032] Figure 5 This is a schematic structural diagram of a cover plate of a loop heat pipe heat dissipation device in one embodiment;

[0033] Figure 6 is a cross-sectional view of an evaporator of a loop heat pipe heat dissipation device in one embodiment;

[0034] Figure 7 Schematic diagram of the flow of heat transfer medium in a loop heat pipe heat dissipation device in one embodiment;

[0035] Figure 8A schematic diagram of the structure of a condenser of a loop heat pipe heat dissipation device in one embodiment;

[0036] Fig. 9 A schematic diagram of the structure of a condensing pipeline of a loop heat pipe heat dissipation device in one embodiment;

[0037] Fig.10 Schematic diagram of a microscopic structure of a liquid wick in a loop heat pipe heat dissipation device in one embodiment.

[0038] 1. Evaporator; 11. Bottom plate; 111. Groove; 12. Liquid absorbent core structure; 121. First liquid absorbent core; 122. Second liquid absorbent core; 123. Third liquid absorbent core; 124. Main body; 125. Fitting part; 126. First end face; 127. Support part; 13. Cover plate; 131. Liquid working medium inlet; 132. Steam outlet; 14. Sealing structure; 15. Compensation cavity; 16. Evaporation chamber; 17. Blocking part; 171. Blocking plate; 172. Docking part; 173. Second end face; 18. Liquid flow channel; 181. Liquid separation port; 19. Boss; 2. Condenser; 21. Condensation pipeline; 22. Fins; 3. Steam pipeline; 4. Liquid pipeline; 41. Liquid injection port.

[0039] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0041] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0042] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, "and / or" in the full text includes three solutions. Taking A and / or B as an example, it includes technical solution A, technical solution B, and technical solution that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0043] refer to Figures 1 to 6 The present application provides a loop heat pipe heat dissipation device, which includes an evaporator 1, a condenser 2, a steam pipeline 3 and a liquid pipeline 4. The evaporator 1 includes a bottom plate 11, a liquid wick structure 12, a cover plate 13 and a sealing structure 14. The cover plate 13 is arranged on the bottom plate 11. The bottom plate 11 and the cover plate 13 form a vacuum cavity. The liquid wick structure 12 is arranged in the vacuum cavity. The liquid wick structure 12 is used to store liquid heat transfer medium. The liquid wick structure 12 is used to cooperate with the cover plate 13 to separate the vacuum cavity into a compensation cavity 15 and an evaporation chamber 16 arranged at intervals. The sealing structure 14 is arranged at one end of the cover plate 13 close to the bottom plate 11, and the position of the sealing structure 14 corresponds to the position of the liquid wick structure 12. The shape of the sealing structure 14 also corresponds to the shape of the liquid wick structure 12. The shape of the liquid core structure 12 corresponds to that of the sealing structure 14, and one end of the sealing structure 14 away from the cover plate 13 is used to abut against the liquid absorption core structure 12 to achieve gas-liquid isolation between the compensation chamber 15 and the evaporation chamber 16; the condenser 2 is vertically arranged above the evaporator 1, and the condenser 2 is connected to the evaporator 1; one end of the steam pipeline 3 is connected to the evaporation chamber 16, and the other end is connected to the condenser 2. The heat transfer medium is heated and evaporated from liquid to gas in the liquid absorption core structure 12, and the gaseous heat transfer medium enters the condenser 2 through the evaporation chamber 16 and the steam pipeline 3; one end of the liquid pipeline 4 is connected to the compensation chamber 15, and the other end is connected to the condenser 2. The condenser 2 is used to condense the gaseous heat transfer medium into liquid heat transfer medium, and the liquid pipeline is used to transport the liquid heat transfer medium to the compensation chamber 15.

[0044] The loop heat pipe cooling device provided in the present application changes the liquid wick structure 12 so that the compensation chamber 15 and the evaporation chamber 16 form a coplanar structure, and a sealing structure 14 is also provided on the cover plate 13. The sealing structure 14 realizes a tight connection between the cover plate 13 and the top of the liquid wick structure 12, so that the steam in the evaporation chamber 16 is difficult to be transmitted from the gap between the top of the liquid wick structure 12 and the cover plate 13 to the compensation chamber 15, so that the steam in the evaporation chamber 16 can basically be transmitted to the condenser 2 via the steam pipeline 3, thereby improving the gas-liquid isolation performance in the evaporator 1, solving the problem of air leakage and heat leakage from the evaporation chamber 16 to the compensation chamber 15, and thus improving the heat dissipation performance. In addition, the present application also maximizes the use of the longitudinal space inside the server by vertically disposing the condenser 2 above the evaporator 1, which can reduce the floor space occupied by the present application in the horizontal space. The condenser 2 is vertically disposed above the evaporator 1, and gravity can be used to achieve the reflux of the liquid heat transfer medium in the condenser 2, thereby reducing the pressure loss of the gaseous heat transfer medium in the condenser 2, thereby improving the overall circulation driving force.

[0045] Specifically, the cover plate 13 is also provided with a liquid working medium inlet 131 and a steam outlet 132. The liquid working medium inlet 131 is connected to the compensation chamber 15, and one end of the liquid pipeline 4 is connected to the liquid working medium inlet 131, thereby realizing the connection between the liquid pipeline 4 and the compensation chamber 15, and the steam outlet 132 is connected to the evaporation chamber 16, and one end of the steam pipeline 3 is connected to the steam outlet 132, thereby realizing the connection between the steam pipeline 3 and the evaporation chamber 16.

[0046] The working principle of the loop heat pipe cooling device of the present application is as follows: during normal operation, the bottom plate 11 is the evaporation end, and the condenser 2 is the condensation end. The bottom surface of the bottom plate 11 is tightly fitted to the chip through a high thermal conductivity interface material. The chip generates heat during operation, and the heat is transmitted to the liquid wick structure 12 through the bottom plate 11. The liquid heat transfer medium in the liquid wick structure 12 absorbs heat and evaporates to form steam. The steam quickly fills the evaporation chamber 16. Driven by the pressure difference, the steam is quickly transmitted to the condenser 2 through the steam outlet 132 in the steam pipeline 3. The condenser 2 and the environment are connected through convection and Heat exchange is carried out by radiation, so that the steam quickly condenses on the inner surface of the condensation pipeline 21 to release heat. The condensed liquid condenses and flows back to the liquid pipeline 4 under the action of pressure difference and gravity, and further flows back to the compensation chamber 15 of the evaporator 1 through the liquid working medium inlet 131. The liquid working medium in the compensation chamber 15 is evenly distributed to the outer surface of the liquid wick structure 12, and driven by the capillary force of the liquid wick structure 12, it flows back to the evaporation chamber 16 of the bottom plate 11, so that the loop heat pipe phase change heat dissipation device can work in a cycle, continuously transfer the heat of the chip to the environment, thereby reducing the chip temperature.

[0047] Specifically, the heat transfer medium is a phase change liquid. In the present embodiment, it can be a high boiling point medium at room temperature such as water, methanol, ethanol, etc., or a low boiling point medium such as liquid ammonia, propylene, etc.

[0048] Specifically, the condenser 2, the steam pipeline 3, the liquid pipeline 4, the cover plate 13, and the bottom plate 11 are made of metal materials such as aluminum and copper.

[0049] refer to Figure 8 The loop heat pipe cooling device of the present application also includes a liquid injection port 41. The liquid pipeline 4 is provided with a liquid injection port 41, and the liquid injection port 41 is arranged close to the liquid working medium inlet 131. The liquid injection port 41 is used to perform vacuum and liquid injection operations on the loop heat pipe cooling device.

[0050] refer to Figure 1 , Figure 2 and Figure 6 The liquid wick structure 12 includes a first liquid wick 121, a second liquid wick 122 and a third liquid wick 123. A groove 111 is provided on the top surface of the bottom plate 11. The first liquid wick 121, the second liquid wick 122 and the third liquid wick 123 are arranged in the groove 111. The first liquid wick 121 is used to store liquid heat transfer medium. The first liquid wick 121 is used to cooperate with the cover plate 13 to separate the vacuum chamber into a compensation chamber 15 and an evaporation chamber 16. The second liquid wick 122 is located below the first liquid wick 121. The second liquid wick 122 is provided Placed in the evaporation chamber 16, the thermal conductivity of the second liquid absorbent core 122 is greater than the thermal conductivity of the first liquid absorbent core 121, the second liquid absorbent core 122 is used for the liquid heat transfer medium to be heated and phase-changed into a gaseous heat transfer medium, the position of the sealing structure 14 corresponds to the position of the first liquid absorbent core 121, the sealing structure 14 is used to abut against the first liquid absorbent core 121, the third liquid absorbent core 123 is arranged around the edge of the first liquid absorbent core 121, the third liquid absorbent core 123 is located in the compensation cavity 15, and the third liquid absorbent core 123 is used to absorb and store liquid heat transfer medium.

[0051] Specifically, since the first liquid absorbent core 121 and the third liquid absorbent core 123 are sintered with low thermal conductivity metals such as nickel, and the third liquid absorbent core 123 is thickened, and the second liquid absorbent core 122 is sintered with high thermal conductivity metals such as copper, the heat conduction of the evaporation chamber 16 to the first liquid absorbent core 121 and the third liquid absorbent core 123 can be greatly reduced, so that the phase change of the heat transfer medium occurs on the second liquid absorbent core 122, thereby preventing the steam generated by the phase change of the heat transfer medium on the side of the first liquid absorbent core 121 close to the compensation cavity 15 and the third liquid absorbent core 123 from flowing into the compensation cavity 15, thereby further improving the gas-liquid insulation performance in the evaporator 1.

[0052] Specifically, refer to Figure 3The evaporator 1 also includes a boss 19, which is arranged at one end of the bottom plate 11 away from the cover plate 13, and the position of the boss 19 corresponds to the position of the second liquid absorbent core 122. The boss 19 is used to fit in contact with the heat source to position the heating surface, which can further reduce the heat directed to the first liquid absorbent core 121 and the third liquid absorbent core 123, avoiding the generation of steam inside the first liquid absorbent core 121 and the third liquid absorbent core 123 and the compensation cavity 15, which affects the performance of the loop heat pipe.

[0053] Specifically, the shapes and sizes of the liquid wick structure 12 and the groove 111 match each other, and the thickness of the groove 111 is 0.2-0.5 mm.

[0054] Specifically, the third wick 123 is a capillary structure, and the third wick 123 is disposed on the surface of the compensation cavity 15, and the third wick 123 is respectively connected to the first wick 121 and the second wick 122. The wick wick has a larger liquid absorption area, which reduces the risk of dry burning inside the evaporator 1 and increases the heat transfer limit of the evaporator 1.

[0055] refer to Figure 2 and Figure 6 The first liquid absorbent core 121 includes a main body 124, two matching parts 125 and a plurality of supporting parts 127. The two matching parts 125 are arranged at two ends of the main body 124. The matching part 125 is provided with a first end surface 126 at one end away from the main body 124. The plurality of supporting parts 127 are arranged at intervals along the length direction of the main body 124, and the supporting parts 127 and the matching parts 125 are located on the same side of the main body 124. The evaporator 1 also includes two blocking parts 17. The two blocking parts 17 are arranged on opposite side walls of one end surface of the cover plate 13 close to the bottom plate 11. The blocking part 17 includes a blocking plate 171 and a docking part 17 2, one end of the blocking plate 171 is connected to the inner side wall of the cover plate 13, and the other end of the blocking plate 171 is connected to the docking portion 172. The blocking portion 17 is used to abut against the top surface of the bottom plate 11. The docking portion 172 is provided with a second end surface 173. The first end surface 126 and the second end surface 173 are both inclined surfaces, and the second end surface 173 and the first end surface 126 are complementary angles to each other. The second end surface 173 is used to be connected to the first end surface 126. The first liquid absorbent core 121 is used to cooperate with the blocking plate 171 and the docking portion 172, so that when the cover plate 13 and the bottom plate 11 are connected to each other, the compensation chamber 15 and the evaporation chamber 16 are isolated.

[0056] Specifically, the main body 124 and the matching part 125 are vertically arranged, and the main body 124 and the two matching parts 125 are enclosed to form a U-shaped structure. The bottom of the U-shaped structure is the compensation cavity 15, and the top of the U-shaped structure is the evaporation chamber 16. Therefore, the overall shape of the compensation cavity 15 is also a U-shaped structure. The compensation cavity 15 is a U-shaped structure, which increases the liquid absorption area of ​​the liquid absorption core structure 12 and accelerates the internal liquid renewal of the liquid absorption core structure 12, thereby realizing efficient heat dissipation of the loop heat pipe under high power.

[0057] Furthermore, the main body 124, the matching part 125 and the supporting part 127 are all columnar structures, which can support the vacuum chamber. The multiple supporting parts 127 are perpendicular to the first absorbent core 121, forming multiple small U-shaped steam flow channels. The main body 124, the matching part 125 and the supporting part 127 form a comb-tooth shape, and the second absorbent core 122 is also a comb-tooth shape, and the comb teeth of the first absorbent core 121 and the second absorbent core 122 are interspersed with each other.

[0058] Specifically, the blocking plate 171 is located on two opposite corners on the same side of the cover plate 13. The blocking plate 171 is a plate-like structure. The blocking plate 171 is used to block the steam generated by the phase change of the second absorbent core 122 from flowing to the area of ​​the third absorbent core 123. The vertical cross-section shape of the docking portion 172 is a right triangle, and a sealing structure 14 is also provided on the second end surface 173 of the docking portion 172.

[0059] Furthermore, the sealing structure 14 is a labyrinth sealing structure, and the sealing structure 14 is formed by processing three metal sealing ring structures on the cover plate 13. During the integrated welding process of the evaporator 1, the metal sealing rings are welded together with the first liquid wick 121 and the second liquid wick 122 under high temperature and high pressure, thereby ensuring the gas-liquid isolation performance in the evaporator 1 and solving the problem of air leakage from the evaporation chamber 16 to the compensation chamber 15. The cover plate 13, the liquid wick structure 12 and the bottom plate 11 are integrated by welding technology, which not only ensures the sealing performance, but also can greatly reduce the contact thermal resistance between the liquid wick structure 12 and the bottom plate 11, thereby improving the evaporation efficiency.

[0060] Specifically, by providing a baffle plate 171 and a docking portion 172, the second end face 173 of the docking portion 172 is an inclined surface, and the first end face 126 and the second end face 173 are complementary angles to each other, so that the contact area between the second end face 173 and the first liquid absorbent core 121 can be increased, thereby increasing the laying area of ​​the sealing structure 14 on the docking portion 172, further improving the sealing effect, and thus improving the gas-liquid isolation performance in the evaporator 1.

[0061] refer to Figure 5The evaporator 1 further includes a liquid flow channel 18, which is disposed in the cover plate 13 and is disposed circumferentially around the compensation chamber 15. The liquid flow channel 18 is connected to the compensation chamber 15, and one end of the liquid flow channel 18 is connected to the liquid pipeline 4. The liquid flow channel 18 is used to transport the liquid heat transfer medium into the compensation chamber 15. The liquid flow channel 18 is provided with a plurality of liquid separation ports 181, which are disposed at intervals, and the liquid separation ports 181 are used to allow the heat transfer medium in the liquid separation pipeline to flow out into the compensation chamber 15.

[0062] Specifically, the liquid flow channel 18 is a U-shaped structure, which is used for uniform distribution of the refluxed liquid heat transfer medium. To ensure uniform distribution of the heat transfer medium, the liquid flow channel 18 is evenly arranged with multiple liquid separation ports 181, which can evenly transport the refluxed liquid to the surface of the liquid wick structure 12, thereby preventing local dry burning of the liquid wick structure 12. The height of the liquid separation port 181 can be designed based on the flow rate of the refluxed liquid, and the liquid separation port 181 is preferably toward the bottom of the liquid wick structure 12.

[0063] refer to Figure 7 , 5 is a heat source, 6 is a refluxed liquid heat transfer medium, 7 is a gaseous heat transfer medium, the heat source is located at the center of the wick structure 12, the liquid heat transfer medium reaches the compensation chamber 15 through the liquid flow channel 18, and diffuses to various parts of the U-shaped compensation chamber 15 under the suction action of gravity and the capillary structure, and then reaches the top of the heat source through the wick structure 12 for phase change heat dissipation. The steam generated by the phase change of the liquid heat transfer medium is collected in the evaporation chamber 16 through the steam flow channel between the second wick 122, and then enters the steam pipeline 3 through the steam outlet 132 of the evaporator 1.

[0064] refer to Figures 8 to 9 The condenser 2 includes a condensation pipeline 21 and fins 22. One end of the condensation pipeline 21 is connected to the steam pipeline 3, and the other end of the condensation pipeline 21 is connected to the liquid pipeline 4. The fins 22 are arranged around the condensation pipeline 21. The height of the condensation pipeline 21 gradually decreases from the end connected to the steam pipeline 3 to the end connected to the condensation pipeline 21. Since the condenser 2 adopts the method of installing fins 22 outside the tube for air cooling and heat dissipation, the heat dissipation area is expanded by 17 times. Since the main driving force of the loop heat pipe heat dissipation device is the capillary suction force of the liquid absorption core, the driving force should mainly act on the gas-liquid renewal in the evaporator 1. The condenser 2 is arranged around the tube as an overall descending structure, and gravity is used to realize the reflux of liquid in the condenser 2, reduce the pressure loss of steam in the condenser 2, and enhance the overall circulation driving force of the loop heat pipe.

[0065] The interior of the condensation pipe 21 is also provided with a corrugated groove structure, which utilizes the micro-groove structure to increase the condensation heat transfer area, reduce the condensation liquid film thickness and form convection disturbances, thereby improving the condensation heat transfer efficiency and thus improving the condensation limit of the loop heat pipe phase change heat dissipation device.

[0066] By setting the condenser 2 as a tube-fin structure and adopting the overall bending forming of the non-smooth pipeline, the sealing performance of the loop heat pipe is enhanced, and the condensation heat transfer efficiency of the inner wall of the pipeline is increased by utilizing the reinforced structure of the inner wall of the pipeline, thereby improving the condensate reflux efficiency; the array of closely spaced fins 22 structure greatly expands the heat dissipation area of ​​the condenser 2 and improves the condensation limit of the loop heat pipe phase change heat dissipation device.

[0067] The present invention also provides a method for preparing a loop heat pipe phase change heat dissipation device, comprising the following steps:

[0068] S1, processing and manufacturing the cover plate 13, the bottom plate 11, the liquid pipeline 4 and the steam pipeline 3;

[0069] S2, bending to form a condensation pipeline 21, making fins 22, and assembling the condensation pipeline 21 and the fins 22 to obtain a condenser 2;

[0070] Specifically, an inner groove tube is used for bending, a single copper sheet is processed by laser cutting technology, and the fin 22 and the condensation pipeline 21 are welded into a whole by a brazing process.

[0071] S3, preparing the liquid wick structure 12 by using a metal powder sintering process;

[0072] The specific operation is: use a certain amount of metal powder oxide, mix it evenly and put it into the mold, do not apply pressure, and reduce it in a high-temperature box-type reducing atmosphere furnace. The powder particle size is 50-200μm, the sintering temperature is 650-880℃, and the insulation time is 60-180min. The large agglomerated particles in the reduced metal powder are broken into uniform smaller particles, mixed evenly and put into the mold, and pressure sintered in a high-temperature box-type atmosphere furnace. The sintering temperature is 750-850℃, and the insulation time is 30-120min.

[0073] S4, using an electrodeposition process to improve the performance of the liquid wick structure 12;

[0074] The specific operation is: connect the liquid wick structure 12 to the cathode of the electrolytic cell, use a mixed solution of copper sulfate and sulfuric acid as the electrolyte, the current density is 0.1A~1A / cm2, and the electrodeposition time is 1~60min.

[0075] Specifically, refer to Fig.10 The liquid wick structure 12 uses large-size powder sintering as a skeleton support to achieve high permeability and low flow resistance; an electrodeposition process is used to form a layer of nanoporous structure on the surface of the internal metal particles of the liquid wick structure 12 to form small pores to achieve high capillary pressure head, which solves the mutual restriction problem between the capillary wick permeability and the capillary force, and further improves the circulation driving force of the loop heat pipe and the liquid replenishment and wetting ability of the bottom plate 11 of the evaporator 1;

[0076] S5, the wick structure 12 is arranged between the bottom plate 11 and the cover plate 13, so that the sealing structure 14 arranged in the cover plate 13 is in contact with the top surface of the wick structure 12, the bottom of the wick structure 12 is in contact with the top surface of the bottom plate 11, and the wick structure 12 divides the vacuum cavity formed by the cover plate 13 and the bottom plate 11 into the compensation cavity 15 and the evaporation chamber 16 arranged at intervals, and then the bottom plate 11 and the cover plate 13 are sealed and connected;

[0077] Specifically, the evaporator 1 is assembled and sealed by welding process, the welding temperature is 700°C, the welding time is 30s, and the welding pressure is 0.2MPa;

[0078] S6, sealingly connecting the steam pipeline 3 to the evaporator 1 and the condenser 2 respectively, and sealingly connecting the liquid pipeline 4 to the evaporator 1 and the condenser 2 respectively;

[0079] S7, a liquid injection port 41 is reserved in the liquid pipeline 4, and the loop heat pipe phase change heat dissipation device is evacuated through the liquid injection port 41 to form a vacuum cavity between the bottom plate 11 and the cover plate 13, and then a liquid heat transfer medium is injected through the liquid injection port 41 and then sealed;

[0080] Specifically, after step S3, the step further includes S31, using acetone solvent to ultrasonically vibrate the sintered liquid wick structure 12 to remove oil stains on the surface of the liquid wick structure 12 and internal sintering impurities, the ultrasonic time is 10 minutes, repeated 3 to 5 times, and placed in a vacuum oven for drying, the drying temperature is 30 to 50° C., and the drying time is 8 to 12 hours.

[0081] After steps S4 and S5, the process further includes S41 and S51, grinding the welding surface with sandpaper to remove surface burrs, and soaking the welding surface with ethanol solution to remove surface oil stains.

[0082] After step S6, the process further includes step S61, placing the evaporator 1 in a reduction furnace, introducing 6% nitrogen and hydrogen gas to reduce the liquid wick 600, and the reduction time is 60 minutes. After the reduction, the device is immediately filled with liquid and sealed.

[0083] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A loop heat pipe heat dissipation device, characterized in that: include: An evaporator, the evaporator comprising a base plate, a wick structure, a cover plate and a sealing structure, the cover plate being arranged on the base plate, the base plate and the cover plate forming a vacuum cavity, the wick structure being arranged in the vacuum cavity, the wick structure being used to store a liquid heat transfer medium, the wick structure being used to cooperate with the cover plate to separate the vacuum cavity into a compensation cavity and an evaporation chamber which are arranged at intervals, the sealing structure being arranged at one end of the cover plate close to the base plate, and the position of the sealing structure corresponds to the position of the wick structure, and the end of the sealing structure away from the cover plate is used to abut against the wick structure to achieve gas-liquid separation between the compensation cavity and the evaporation chamber; A condenser is vertically arranged above the evaporator, and the condenser is connected to the evaporator; a steam pipeline, one end of which is connected to the evaporation chamber and the other end of which is connected to the condenser; and a liquid pipeline, one end of which is in communication with the compensation chamber, and the other end of which is in communication with the condenser; The wick structure comprises a first wick and a second wick, the first wick being arranged at one end of the bottom plate close to the cover plate, the first wick being used to cooperate with the cover plate to separate the vacuum chamber into a compensation chamber and an evaporation chamber, the first wick being used to store the liquid heat transfer medium, the second wick being located below the first wick, the second wick being arranged in the evaporation chamber, the thermal conductivity of the second wick being greater than the thermal conductivity of the first wick, the second wick being used to heat the liquid heat transfer medium to be phase-changed into a gaseous heat transfer medium, the position of the sealing structure being corresponding to the position of the first wick, the sealing structure being used to abut against the first wick; The first liquid absorbent core includes a main body and two matching parts, the two matching parts are relatively arranged at the two ends of the main body, and a first end face is provided at one end of the matching part away from the main body. The evaporator also includes two blocking parts, the two blocking parts are relatively arranged at the two ends of the cover plate, the blocking part includes a blocking plate and a docking part, one end of the blocking plate is connected to the inner side wall of the cover plate, and the other end of the blocking plate is connected to the docking part, the blocking part is used to abut against the top surface of the bottom plate, and the docking part is provided with a second end face, the first end face and the second end face are both inclined surfaces, and the second end face and the first end face are complementary angles to each other, and the second end face is used to dock with the first end face, and the first liquid absorbent core is used to cooperate with the blocking plate and the docking part, so that when the cover plate and the bottom plate are docked, the gas-liquid separation of the compensation cavity and the evaporation chamber is realized.

2. The loop heat pipe heat dissipation device according to claim 1, characterized in that: The first liquid absorbent core further comprises a support portion, wherein the support portion is arranged at intervals on the same side of the main body along the length direction of the main body, and the support portion is used to divide the evaporation chamber into steam flow channels arranged at intervals.

3. The loop heat pipe heat dissipation device according to claim 1, characterized in that: The evaporator further comprises a boss, which is arranged at an end of the bottom plate away from the cover plate, and the position of the boss corresponds to the position of the second liquid absorption core.

4. The loop heat pipe heat dissipation device according to claim 1, characterized in that: The evaporator also includes a liquid flow channel, which is arranged in the cover plate and is circumferentially arranged around the compensation chamber. The liquid flow channel is connected to the compensation chamber, and one end of the liquid flow channel is connected to the liquid pipeline. The liquid flow channel is used to transport the liquid heat transfer medium into the compensation chamber.

5. The loop heat pipe heat dissipation device according to claim 4, characterized in that: The liquid flow channel is provided with a plurality of liquid separation ports, which are arranged at intervals, and the liquid separation ports are used to allow the heat transfer medium in the liquid flow channel to flow out into the compensation chamber.

6. The loop heat pipe heat dissipation device according to claim 1, characterized in that: The condenser comprises a condensation pipeline and fins, one end of the condensation pipeline is communicated with the steam pipeline, the other end of the condensation pipeline is communicated with the liquid pipeline, and the fins are arranged around the condensation pipeline.

7. The loop heat pipe heat dissipation device according to claim 6, characterized in that: The height of the condensation pipeline gradually decreases from one end connected to the steam pipeline to one end connected to the condensation pipeline.

8. A method for preparing the loop heat pipe heat dissipation device according to claim 1, characterized in that: The following steps are involved: Processing and manufacturing cover plates, bottom plates, liquid pipelines and steam pipelines; Bending to form a condensing pipe, making fins, and assembling the condensing pipe and the fins to obtain a condenser; The liquid wick structure is prepared by using a metal powder sintering process; The performance of the wick structure is improved by using an electrodeposition process; The wick structure is arranged between the bottom plate and the cover plate, so that the sealing structure arranged in the cover plate abuts against the top surface of the wick structure, the bottom of the wick structure fits with the top surface of the bottom plate, and the wick structure divides the vacuum cavity formed by the cover plate and the bottom plate into a compensation cavity and an evaporation chamber arranged at intervals, and then the bottom plate and the cover plate are sealed and connected; The steam pipeline is sealed and connected to the evaporator and the condenser respectively, and the liquid pipeline is sealed and connected to the evaporator and the condenser respectively.

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