A circular aluminum dual-phase phase-change heat-spreading plate and a manufacturing method thereof

Abstract

The application discloses a circular aluminum two-phase phase-change uniform temperature plate and a manufacturing method thereof. The circular aluminum two-phase phase-change uniform temperature plate comprises a uniform temperature plate body, the uniform temperature plate body comprises a matched upper body and a lower body, the upper body and the lower body are matched to form an evaporation cavity, and a working medium is arranged in the evaporation cavity. The uniform temperature plate body is arranged in a circular ring shape, a first through hole is arranged at the center of the uniform temperature plate body, the gravity center of the uniform temperature plate body is coincident with the geometric center of the first through hole, and the manufacturing method of the circular aluminum two-phase phase-change uniform temperature plate comprehensively considers the problems that the uniform temperature plate needs to keep dynamic balance during rotation, the aluminum material is easy to be oxidized during welding, and the generated welding slag is easy to block the liquid injection groove. Compared with the existing uniform temperature plate, the circular aluminum two-phase phase-change uniform temperature plate has the advantages of lower price, lower weight, excellent mechanical strength, satisfaction of the demand of the uniform temperature plate which is sensitive to weight, and keeping of dynamic balance during high-speed rotation.

Description

Technical Field

[0001] This invention relates to the field of radiator technology, and in particular to a circular aluminum dual-phase phase change heat exchanger and its manufacturing method. Background Technology

[0002] A vapor chamber is a vacuum cavity with a capillary structure on its inner wall. It is made of a metal shell, capillary structure, and working medium through processes such as annealing, vacuuming, and sealing. When heat is conducted from the heat source to the evaporation zone, the working medium in the low vacuum environment begins to vaporize. It absorbs heat and expands rapidly, quickly filling the entire evaporation zone. When the vaporized working medium comes into contact with a cooler area, condensation occurs. This condensation releases the heat accumulated during evaporation. The condensed working medium then returns to the heat source in the evaporation zone via the capillary structure. This process repeats continuously within the cavity, achieving a cooling effect.

[0003] Specific heat capacity (represented by the symbol c) refers to the amount of heat absorbed or released per unit mass of an object when its temperature changes by a unit. Generally, the higher the specific heat capacity, the better the heat dissipation effect. The specific heat capacity of aluminum is 0.88 J / (g·℃), and that of oxygen-free copper is 0.39 J / (g·℃). However, the density of copper is 8.95 g / cm³, while the density of aluminum is 2.7 g / cm³. The weight of the same volume of copper is more than three times that of aluminum, and the price of copper is generally more than three times that of aluminum. Therefore, aluminum is lighter, has better thermal conductivity, is cheaper than copper, and has better mechanical strength. The industry has long hoped that aluminum could replace copper in the manufacture of heat spreaders for low-power applications, meeting the needs of low-power, high-strength, and low-cost thermal conductive components.

[0004] However, existing heat spreaders are mainly made of copper or stainless steel. The fundamental reason is that the manufacturing process inevitably involves welding copper shells together. Copper-to-copper welding does not require solder, or uses copper brazing material as the solder, and produces no slag after welding. Therefore, the injection port and injection tank will not be blocked during the welding process. Welding aluminum to aluminum is more difficult. Aluminum forms an oxide layer at room temperature and only melts at temperatures above 2000℃. Because aluminum oxidizes easily, the oxide layer must be removed, usually using deoxidizing solder and flux. This inevitably produces slag after welding. The diameter of the injection port and injection tank is generally within 3mm, and the slag often blocks these ports and tanks. Vacuum brazing requires a layer of weld metal on the welding surface, but during the welding melting process, slag often blocks the injection port and injection tank. This has prevented the successful development of aluminum vapor chambers. Another reason for the lack of success with aluminum vapor chambers is that existing vapor chambers sinter capillary structures on the inner wall of the copper shell, relying mainly on the capillary structure to absorb water and achieve liquid medium reflux. Existing vapor chambers are generally thin flat plates. Taking copper vapor chambers as an example, copper mesh or copper powder is sintered on the inner wall of the copper shell to form capillary structures. However, because aluminum shells are prone to oxidation, their capillary structures cannot be completed using traditional sintering methods. This is also one of the reasons why aluminum vapor chambers have not been successfully developed.

[0005] Existing vapor chambers have high requirements for thermal power and are not very sensitive to their own weight. However, with the exponential growth of data and computation, especially for circular vapor chambers that rotate with the heat source, copper has a higher density, resulting in a heavier weight for the same volume of copper vapor chambers. Furthermore, higher rotation speeds make weight requirements more sensitive. Therefore, the development of high-speed rotating circular aluminum two-phase phase change vapor chambers has become an urgent problem to be solved in this field. Summary of the Invention

[0006] To address the aforementioned problems, the present invention aims to provide a circular aluminum dual-phase phase change heat spreader and its manufacturing method. This invention comprehensively considers the issues of maintaining dynamic balance during rotation, the susceptibility of aluminum to oxidation during welding, and the tendency of weld slag to clog the injection tank. The resulting circular aluminum dual-phase phase change heat spreader is cheaper and lighter, meeting the needs of heat spreaders that are sensitive to weight requirements.

[0007] To achieve the above objectives, the present invention provides a circular aluminum dual-phase phase change heat exchanger, comprising a heat exchanger body, wherein the heat exchanger body comprises an upper body and a lower body that cooperate with each other, wherein a first capillary structure is etched on the inner wall of the upper body, and a second capillary structure is etched on the inner wall of the lower body, wherein the first capillary structure communicates with the second capillary structure, wherein the upper body and the lower body cooperate to form an evaporation chamber, and a working medium is provided in the evaporation chamber; The heat spreader body is arranged in a circular shape, and a first through hole is provided at the center of the heat spreader body. The center of gravity of the heat spreader body coincides with the geometric center of the first through hole.

[0008] Preferably, the lower body has a first protrusion at the center hole, a first groove on the first protrusion, and a liquid injection groove on the lower body. One end of the liquid injection groove communicates with the first groove, and the other end communicates with the evaporation chamber. The evaporation chamber, the liquid injection groove, and the first groove form a closed cavity.

[0009] Preferably, the lower body is provided with a main flow channel, the upper body is provided with a secondary flow channel, and the evaporation chamber, the main flow channel, and the secondary flow channel are connected.

[0010] Preferably, the lower body has a second protrusion and the upper body has a second groove. The second protrusion is located below the second groove, and the second protrusion and the second groove form the secondary flow channel. The secondary flow channel divides the main flow channel into a first main flow channel and a second main flow channel. The evaporation chamber, the first main flow channel, the secondary flow channel, and the second main flow channel are connected in sequence.

[0011] Preferably, the heat spreader body further includes a plurality of uniformly circumferentially distributed guide columns, the two ends of which are vertically connected to the upper body and the lower body respectively; a third capillary structure is etched on the outer surface of the guide column, the third capillary structure being connected to the adjacent first capillary structure and second capillary structure; a plurality of support columns are provided on the lower body, the two ends of which are vertically connected to the upper body and the lower body respectively.

[0012] Preferably, in the working state, the temperature distribution plate body rotates at a speed of 2000-4000 rpm, the diameter of the first through hole is greater than the length of the injection groove; the first protrusion is provided with an injection port, which is perpendicular to and communicates with the first groove; the injection groove is provided with one of the following structures: trapezoidal cross-section, rectangular cross-section, circular cross-section, semi-circular cross-section, or elliptical cross-section.

[0013] This invention also provides a method for manufacturing a circular aluminum two-phase phase change heat spreader, comprising the following steps: S1, the production of the upper body blank and the lower body blank, both of which have a square cross-section structure. The upper body blank has an upper groove, and the lower body blank has a lower groove that matches the upper groove. The upper groove and the lower groove are circular. A first through hole is provided at the center of the upper groove and the lower groove. The center of gravity of the upper body blank and the lower body blank coincides with the geometric center of the first through hole. S2, Etching of the first capillary structure and the second capillary structure: Etching the first capillary structure on the upper tank and etching the second capillary structure on the lower tank. S3, Fabrication of the injection groove: The injection groove is stamped on the lower body blank; a first protrusion is provided at the center hole of the lower body blank, and a first groove is provided on the first protrusion. One end of the injection groove communicates with the first groove, and an injection port is provided on the first protrusion. The injection port is perpendicular to and communicates with the first groove. S4, Welding preparation: Place the carbon rod into the first groove; S5, the upper body blank and the lower body blank are welded together, and the upper body blank and the lower body blank are sealed by first aluminum brazing. After welding, an evaporation chamber is formed. During the first aluminum brazing sealing process, the carbon rod is carbonized into carbon slag. The inner wall of the evaporation chamber is provided with the first capillary structure and the second capillary structure in step S3. S6, Remove the carbon slag, clean the carbon slag in the first groove, and seal the end opening of the first groove; S7, Helium side leak check: Helium is injected into the injection tank and evaporation chamber through the injection port to check for side leaks. If there are side leaks, the leaks are dealt with. If there are no side leaks, the helium check is complete. S8, Liquid medium injection and vacuuming: Liquid medium is injected into the evaporation chamber through the injection port. Then, the evaporation chamber is evacuated, and the injection port is sealed with a second aluminum brazing to maintain a seal between the evaporation chamber and the injection tank, thus obtaining a homogeneous slab. S9. The heat exchange plate blank is machined by milling the upper body blank to the edge of the upper body and the lower body blank to the edge of the lower body to obtain a circular heat exchange plate body. The gravity center of the heat exchange plate body is made to coincide with the geometric center of the first through hole to obtain a circular aluminum two-phase phase change heat exchange plate.

[0014] Preferably, the following steps are also included: S21, the construction of the secondary flow channel involves setting a second groove on the upper body and a second protrusion on the lower body. The second protrusion is located below the second groove, and the secondary flow channel is formed between the second protrusion and the second groove. S91, before machining the uniformly heated slab, the first protrusion is milled off; The first aluminum brazed seal in S5 is made by diffusion welding, using solder deoxidizer treatment, with a welding temperature of 600-650℃, a welding time of 6-9h, and a welding pressure of 20-40MPa. The second aluminum brazed seal in S9 is produced using a gas-protected atmosphere welding furnace, with solder used, a welding temperature of 550-650℃, and a welding time of 2-3.5 hours. The circular aluminum dual-phase phase change heat spreader is made of pure aluminum or aluminum alloy. The solder comprises 10-15% aluminum and 0.2-0.8% silicon, the percentages being by weight.

[0015] Preferably, the carbon rod contains 35-65% carbon by mass, and the carbon rod is a straight rod that mates with the first groove. Alternatively, the carbon rod may include a baffle, a metal wire perpendicular to the baffle, and a plurality of carbon blocks connected in sequence. The carbon blocks have a second through hole at the center that mates with the metal wire, a third groove at one end of the carbon block, and a third protrusion at the other end.

[0016] The present invention also provides a circular aluminum heat sink, comprising a heat spreader and a heat sink plate.

[0017] The beneficial effects of this invention are as follows: The circular aluminum dual-phase phase change heat spreader and manufacturing method provided by this invention, by setting the upper and lower body blanks into a square structure, facilitates positioning and fixing, and makes it easier to keep the center of gravity coincide with the geometric center of the first through hole, thereby ensuring the dynamic balance of the finished heat spreader; by punching a liquid injection groove on the lower body blank, liquid is injected into the evaporation chamber; by placing the carbon rod into the first groove before welding, carbon slag or welding slag is effectively prevented from mixing into the evaporation chamber, ensuring the performance requirements of the heat spreader. (After helium side leakage inspection and liquid medium injection...) After vacuuming, the excess parts at the edges of the upper and lower body blanks are milled off to obtain a circular heat spreader body. The center of gravity of the heat spreader body is then aligned with the geometric center of the first through hole to complete the fabrication of the circular heat spreader. This fabrication method comprehensively considers the need for the heat spreader to maintain dynamic balance during rotation, the easy oxidation of aluminum materials during welding, and the tendency of weld slag to clog the injection tank. Compared with existing heat spreaders, it is cheaper, lighter, and has excellent mechanical strength, meeting the needs of heat spreaders that are sensitive to weight requirements, and can maintain dynamic balance during high-speed rotation. Attached Figure Description

[0018] The accompanying drawings illustrate exemplary embodiments of the invention and, together with the description thereof, serve to explain the principles of the invention. These drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification.

[0019] Figure 1 This is a schematic diagram of the circular aluminum two-phase phase change heat spreader in Example 1; Figure 2 This is a schematic diagram of the structure of the lower body of the circular aluminum two-phase phase change heat spreader in Example 1; Figure 3 This is a schematic diagram of the structure of the body blank under the heat exchanger in Example 1; Figure 4 This is a schematic diagram of the structure of the heat spreader during the liquid injection process in Example 1. Figure 5 This is a schematic diagram of the internal structure of the heat spreader during the liquid injection process in Example 1. Figure 6 for Figure 4 Enlarged structural diagram at point A; Figure 7 This is a schematic diagram of the manufacturing process of the circular aluminum two-phase phase change heat spreader in Example 1; Figure 8 This is a schematic diagram of the carbon rod structure in Example 1; Figure 9 This is a schematic diagram of the circular aluminum two-phase phase change heat spreader in Example 2; Figure 10 This is a schematic diagram of the structure of the lower body of the circular aluminum two-phase phase change heat spreader in Example 2. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings.

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] Example 1: Please refer to Figures 1 to 8 This embodiment 1 includes: A circular aluminum dual-phase phase change heat spreader includes a heat spreader body, which includes an upper body 1 and a lower body 2 that cooperate with each other. A first capillary structure 31 is etched on the inner wall of the upper body 1, and a second capillary structure 32 is etched on the inner wall of the lower body 2. The first capillary structure 31 and the second capillary structure 32 are in communication. The upper body 1 and the lower body 2 cooperate to form an evaporation chamber 11, and a working medium is provided in the evaporation chamber 11. The heat spreader body is circular in shape and made of aluminum, which can be pure aluminum or aluminum alloy. A first through hole 41 is provided at the center of the heat spreader body. The center of gravity of the heat spreader body coincides with the geometric center of the first through hole 41.

[0023] In this embodiment, the circular aluminum biphase phase change heat spreader is mainly used on a heat sink that rotates together with the heat source. The heat sink includes a heat spreader and heat sink fins. The heat source is usually a chip, located below the lower body 2. Taking water as an example, a large amount of heat is generated during operation. The heat is rapidly conducted through the lower body 2 to the first capillary structure 31 and the evaporation chamber 11. Since the evaporation chamber 11 is close to a vacuum state, even a very low amount of heat is enough to cause the water in the first capillary structure 31 and the evaporation chamber 11 to absorb heat and change into water vapor. The water vapor rises continuously in the evaporation chamber 11, and the pressure inside the evaporation chamber 11... As the pressure increases, the high-temperature water vapor (carrying the heat from the chip) continuously flows through the first capillary structure 31 to the second capillary structure 32 and the upper body 1. As the water vapor flows upward, it comes into contact with the lower-temperature upper body 1 and transforms back into liquid water. Under the action of capillary action and gravity, the water returns to the first capillary structure 31 and the evaporation chamber 11. The heat on the water vapor is conducted to the heat sink in contact with it, and the heat sink diffuses the heat away, continuing the heat dissipation cycle and continuously dissipating the heat generated on the chip, thereby reducing the chip temperature.

[0024] Due to technological limitations, existing rotating heat spreaders are all made of copper or stainless steel alloys. Under the same volume conditions, they are heavier and more expensive. At higher rotation speeds, the weight requirements are more sensitive. However, by using aluminum (pure aluminum or aluminum alloy) heat spreaders, the price and weight are lower. The center of gravity of the heat spreader body coincides with the geometric center of the first through hole 41, which can ensure the dynamic balance of the heat spreader during rotation.

[0025] A first protrusion 21 is provided at the center hole of the lower body 2, and a first groove 22 is provided on the first protrusion 21. A liquid injection groove 23 is provided on the lower body 2. One end of the liquid injection groove 23 communicates with the first groove 22, and the other end communicates with the evaporation chamber 11. The evaporation chamber 11 and the liquid injection groove 23 form a closed cavity. A liquid injection port 24 is provided on the first protrusion 21. During the manufacturing process, the first protrusion 21 is mainly used for injecting liquid into the evaporation chamber 11 and for vacuuming. During the liquid injection process, the liquid injection pipe 25 is connected to the liquid injection port 24 for injection. Liquid is injected into the evaporation chamber 11 through the injection port 24, the first groove 22 and the injection groove 23. After the injection is completed, the injection port 24 is sealed to prevent liquid leakage. After the injection and vacuuming, the first protrusion 21 can be milled off as needed, keeping the first through hole 41 as a complete round hole, which can be connected to the rotating shaft of the heat dissipation equipment for rotation. Alternatively, the first protrusion 21 can be retained as needed to match the rotating shaft for rotation, provided that the heat spreader meets the dynamic balance requirements.

[0026] The lower body 2 is provided with a main flow channel, and the upper body 1 is provided with a secondary flow channel 12. The evaporation chamber 11, the main flow channel, and the secondary flow channel 12 are connected in sequence. The main flow channel is formed by the liquid injection tank 23 and the upper body 1, and the secondary flow channel 12 is formed by the groove provided on the upper body 1.

[0027] The lower body 2 has a second protrusion 26, and the upper body 1 has a second groove 27. The second protrusion 26 is located below the second groove 27, and a secondary flow channel 12 is formed between the second protrusion 26 and the second groove 27. The secondary flow channel 12 divides the main flow channel into a first main flow channel and a second main flow channel. The first main flow channel is connected to the evaporation chamber 11, and the second main flow channel is connected to the secondary flow channel 12 and the liquid injection port 24. The evaporation chamber 11, the first main flow channel, the secondary flow channel 12, and the second main flow channel are sequentially connected. The height of the second protrusion 26 is higher than the bottom surface of the upper body 1. Before welding, the carbon rod is placed in the first groove 22, and the carbon rod just touches the second protrusion 26. In this way, the carbon slag after carbonization will also be located between the second protrusion 26 and the liquid injection port 24, effectively preventing carbon slag from being mixed in the evaporation chamber 11 and ensuring the performance requirements of the heat spreader.

[0028] The heat spreader body also includes multiple uniformly circumferentially distributed guide columns 81, with both ends of the guide columns 81 vertically connected to the upper body 1 and the lower body 2, respectively. A third capillary structure is etched on the outer surface of the guide columns 81, and the third capillary structure communicates with the adjacent first capillary structure 31 and second capillary structure 32. Multiple support columns 82 are provided on the lower body 2, with both ends of the support columns 82 vertically connected to the upper body 1 and the lower body 2, respectively. In the working state, the heat spreader rotates at high speed, and the liquid working medium is evenly distributed on the guide columns 81 under the action of centrifugal force during the reflux process. The guide columns 81 can accelerate the reflux speed and flow rate of water, making heat dissipation more uniform and faster, thereby improving the heat dissipation power and temperature uniformity performance of the heat spreader. As the water vapor rises, the pressure inside the evaporation chamber 11 increases. The inner walls of the upper body 1 and the lower body 2 are generally less than 2 mm thick. At this time, the guide column 81 and the support column 82 can play a supporting role, which can prevent the upper body 1 and the lower body 2 from deforming or breaking when the pressure changes, thus extending the service life of the heat spreader.

[0029] In operation, the temperature distribution plate rotates at a speed of 2000-4000 rpm. Due to the limited space allocated to the radiator, to ensure a relatively large width for the evaporation chamber 11 within this confined space, the first through-hole 41 must be as small as possible. The diameter of the first through-hole 41 is less than the sum of the lengths of the first groove 22 and the liquid injection groove 23. Considering the need to prevent solder from entering the evaporation chamber 11 during welding, this embodiment minimizes the length of the liquid injection groove 23, and the diameter of the first through-hole 41 is greater than the length of the liquid injection groove 23. During welding, a carbon rod is placed in the first groove 22, and after welding, it carbonizes into carbon slag. Because the length of the liquid injection groove 23 is relatively short, the... When the inner diameter of the injection tank 23 is larger than the inner diameter of the first groove 22, it effectively prevents carbon slag from mixing into the evaporation chamber 11. The first protrusion 21 is provided with an injection port 24, which is perpendicular to and connected to the first groove 22. The injection tank 23 is provided with one of the following structures: trapezoidal cross section, rectangular cross section, circular cross section, semi-circular cross section, or elliptical cross section. The injection port 24 is designed to facilitate connection with the first groove 22 through the injection pipe 25 and to inject liquid into the evaporation chamber 11. The structure of the first groove 22 is designed to facilitate the shaping of the carbon rod. After the carbon rod is inserted and carbonized, the carbon slag is removed to ensure that the inside of the heat spreader is cleaned of carbon slag and to ensure the yield of the heat spreader.

[0030] The specific production method includes the following steps: S1. Fabrication of the upper body blank 101 and the lower body blank 102: Both the upper body blank 101 and the lower body blank 102 have a square cross-section structure. The upper body blank 101 has an upper groove, and the lower body blank 102 has a lower groove that mates with the upper groove. The upper and lower grooves are circular. A first through hole 41 is provided at the center of the upper and lower grooves. The center of gravity of the upper body blank 101 and the lower body blank 102 coincides with the geometric center of the first through hole 41. The upper groove is the internal space area of ​​the upper body 1, and the lower groove is the internal space area of ​​the lower body 2. After the mating upper and lower grooves are welded, they form the evaporation chamber 11 in the finished heat spreader. Both the upper body blank 101 and the lower body blank 102 have a square cross-section structure. The final finished heat spreader is circular. Compared with a circle, a square shape is easier to position, fix, and set the center coincidence during the manufacturing process. S2, Etching of the first capillary structure 31 and the second capillary structure 32: Etching the first capillary structure 31 on the upper tank and etching the second capillary structure 32 on the lower tank. Unlike existing copper vapor chambers, where capillary structures are formed on the inner wall of the copper shell using sintered copper mesh or copper powder, aluminum shells cannot achieve their capillary structures using traditional sintering methods due to the susceptibility of aluminum to oxidation. In this embodiment, the capillary structure is formed through etching. High-speed rotation places high demands on the dynamic balance of the finished vapor chamber; therefore, the width, depth, and water retention rate of the etched capillary structure need to be determined based on these dynamic balance requirements. S3, Fabrication of the injection groove 23: The injection groove 23 is stamped on the lower body blank 102; a first protrusion 21 is provided at the center hole of the lower body blank 102, and a first groove 22 is provided on the first protrusion 21. One end of the injection groove 23 communicates with the first groove 22, and an injection port 24 is provided on the first protrusion 21. The injection port 24 is perpendicular to and communicates with the first groove 22. S4, Welding preparation: Before welding, carbon rod is placed in the first groove 22; after welding, carbon rod carbonizes to form carbon slag. After cleaning the carbon slag, no solder or carbon slag remains in the first groove 22, effectively preventing carbon slag or welding slag from mixing into the evaporation chamber 11 and ensuring the performance requirements of the heat spreader. S5, the upper body blank 101 and the lower body blank 102 are welded together, and the upper body blank 101 and the lower body blank 102 are sealed by first aluminum brazing. After welding, an evaporation chamber 11 is formed. During the first aluminum brazing sealing process, the carbon rod is carbonized into carbon slag. The inner wall of the evaporation chamber 11 is provided with the first capillary structure 31 and the second capillary structure 32 in step S3. S6, remove the carbon slag, clean the carbon slag in the first groove 22, and seal the end opening of the first groove 22; S7, Helium side leak check: Helium is injected into the injection tank 23 and evaporation chamber 11 through the injection port 24 to check for side leaks. If there are side leaks, the leaks are dealt with. If there are no side leaks, the helium check is completed. S8, Liquid medium injection and vacuuming: Liquid medium is injected into the evaporation chamber 11 through the injection port 24. Then, the evaporation chamber 11 is evacuated, and the injection port 24 is sealed with a second aluminum brazing to keep the evaporation chamber 11 and the injection tank 23 sealed, thus obtaining a homogeneous slab. S9. The heat spreader blank is machined by milling off the excess portions at the edges of the upper body blank 101 and the lower body blank 102, that is, milling off the upper body blank 101 to the edge of the upper body 1, and milling off the lower body blank 102 to the edge of the lower body 2. If necessary, the first protrusion 21 can also be milled off simultaneously to obtain a circular heat spreader body. The center of gravity of the heat spreader body is made to coincide with the geometric center of the first through hole 41 to obtain a circular aluminum two-phase phase change heat spreader. The excess portions at the edges of the upper body blank 101 and the lower body blank 102 are the portions between the outer frames of the upper body blank 101 and the lower body blank 102 and the outer edge portions of the heat spreader body.

[0031] Considering the need for the heat spreader to maintain dynamic balance during rotation, the ease with which aluminum materials oxidize during welding, and the difficulty in cleaning weld slag produced by the solder, which can easily clog the injection groove 23, this embodiment differs from traditional heat spreader manufacturing methods. First, the upper body blank 101 and lower body blank 102 are set into a square structure. An upper groove, a lower groove, and a first protrusion 21 are then fabricated on the square upper and lower body blanks 101 and 102. The square shape facilitates positioning and fixation, ensuring that the center of gravity aligns with the geometric center of the first through hole 41, thus maintaining dynamic balance. Next, the injection groove 23 is stamped on the lower body blank 102. A first groove 22 is provided on the first protrusion 21, with one end of the injection groove 23 communicating with the first groove 22. An injection port 24 is provided on the first protrusion 21, perpendicular to and communicating with the first groove 22. The injection port 24 is designed to facilitate the flow of liquid through the groove. The liquid injection tube 25 is connected to the first groove 22 and injects liquid into the evaporation chamber 11. Before welding, the carbon rod is placed in the first groove 22. The structure of the first groove 22 is designed to facilitate the shaping of the carbon rod and the removal of carbon slag after carbonization, ensuring that the heat spreader is clean of carbon slag and guaranteeing the yield of the heat spreader. The carbon rod is placed in the first groove 22 before welding. After welding, the carbon rod carbonizes to form carbon slag. After cleaning the carbon slag, no solder or carbon slag remains in the liquid injection tank 23 and the first groove 22, effectively preventing carbon slag or welding slag from mixing into the evaporation chamber 11 and ensuring the performance requirements of the heat spreader. After helium side leakage inspection, liquid medium injection and vacuuming, the excess parts at the edges of the upper body blank 101 and the lower body blank 102 are milled off to obtain a circular heat spreader body. The center of gravity of the heat spreader body is made to coincide with the geometric center of the first through hole 41 to complete the production of the circular heat spreader, thereby obtaining a circular aluminum two-phase phase change heat spreader.

[0032] It also includes the following steps: S21, the construction of the secondary flow channel 12 involves setting a second groove 27 on the upper body 1 and a second protrusion 26 on the lower body 2. The second protrusion 26 is located below the second groove 27, and the secondary flow channel 12 is formed between the second protrusion 26 and the second groove 27. The first aluminum brazed seal in S5 is made by diffusion welding, using solder deoxidizer treatment, welding temperature of 600-650℃, welding time of 6-9h, welding pressure of 20-40MPa, drying after welding, and then assembly. The second aluminum brazed seal in S9 is produced using a gas-protected atmosphere welding furnace, with solder used, a welding temperature of 550-650℃, and a welding time of 2-3.5 hours. The circular aluminum dual-phase phase change heat spreader is made of pure aluminum or aluminum alloy. The solder consists of 10-15% aluminum and 0.2-0.8% silicon, percentages by weight.

[0033] Because the pressure applied during welding is relatively small, the upper body blank 101 and the lower body blank 102 are heated as a whole and cooled with the furnace. Therefore, the overall plastic deformation of the heat exchange plate after welding is very small. Moreover, the joint surface of the upper body blank 101 and the lower body blank 102 is difficult to see even under a microscope. The welded parts have high precision and small deformation, so that the upper body blank 101 and the lower body blank 102 can be regarded as a whole after welding, which effectively ensures the sealing performance of the evaporation chamber 11.

[0034] The carbon rod contains 35-65% carbon by mass. It includes a baffle 91, a metal wire 92 perpendicular to the baffle 91, and multiple carbon blocks 93 connected in sequence. Each carbon block 93 has a second through hole (not shown in the figure) at its center that mates with the metal wire 92. One end of each carbon block 93 has a third groove 95, and the other end has a third protrusion 96. The carbon rod consists of multiple carbon blocks 93 connected in series on the metal wire 92. The metal wire 92 is made of materials such as copper, iron, or tungsten wire. The melting point of the metal wire 92 is higher than the welding temperature of the first aluminum brazing seal, ensuring the first aluminum brazing... During the sealing welding process, the carbon rod is not melted. As mentioned earlier, before welding, the carbon rod is placed in the first groove 22, and the baffle 91 abuts against the second protrusion 26. After welding, the carbon rod carbonizes to form carbon slag. The metal wire 92 is pulled out, and the metal wire 92 will pull out the carbon slag together with the baffle 91. Due to the presence of the baffle 91, the carbon slag is completely pulled out from the liquid injection tank 23 and the first groove 22, thereby effectively preventing carbon slag or welding slag from mixing into the evaporation chamber 11. The baffle 91 and the second protrusion 26 provide double protection to ensure that carbon slag does not mix into the evaporation chamber 11, thus ensuring the performance requirements of the heat spreader.

[0035] Example 2, as Figure 9-10 As shown, the difference from Example 1 is that: (1) the first protrusion 21 of the finished heat spreader is milled off; (2) during the manufacturing process, the second protrusion 26 and the second groove 27 are not set; the carbon rod before welding is a straight rod; before the first aluminum brazing seal welding, it is directly placed into the first groove 22 and the liquid injection tank 23 or directly placed into the first groove 22; (3) the carbon rod is a straight rod, which is a straight rod that matches the main channel and the first groove 22; the carbon rod contains 35-65% carbon mass; before welding, the carbon rod is placed into the liquid injection tank 23 and the first groove 22; after welding, the carbon rod carbonizes to form carbon slag; after cleaning the carbon slag, no solder and carbon slag remain in the liquid injection tank 23 and the first groove 22, which effectively prevents carbon slag or welding slag from mixing into the evaporation chamber 11 and ensures the performance requirements of the heat spreader.

[0036] In summary, the circular aluminum dual-phase phase change heat spreader and its manufacturing method provided by this invention involve setting the upper and lower body blanks into a square structure, and fabricating an upper groove, a lower groove, and a first protrusion on the square upper and lower body blanks. The square shape facilitates positioning and fixing, ensuring that the center of gravity coincides with the geometric center of the first through hole, thereby maintaining dynamic balance. A liquid injection groove is stamped on the lower body blank, and a first groove is provided on the first protrusion. One end of the liquid injection groove communicates with the first groove, and a liquid injection port is provided on the first protrusion. The liquid injection port is perpendicular to and communicates with the first groove. The liquid injection port is designed to facilitate connection with the first groove via a liquid injection pipe, injecting liquid into the evaporation chamber. Before welding, a carbon rod is placed in the first groove. The structure of the first groove facilitates the shaping of the carbon rod and the removal of carbon slag after carbonization. By maximizing the length of the first groove while minimizing the length of the liquid injection groove, the overall balance is achieved. The interior of the heat spreader is thoroughly cleaned of carbon slag to ensure a high yield rate and effectively prevent carbon slag or welding slag from entering the evaporation chamber, thus guaranteeing the heat spreader's performance requirements. After helium leak checks, liquid medium injection, and vacuuming, excess material at the edges of the upper and lower body blanks is milled off to obtain a circular heat spreader body. The center of gravity of the heat spreader body is then aligned with the geometric center of the first through hole, completing the circular heat spreader fabrication. This results in a circular aluminum dual-phase phase change heat spreader. This manufacturing method comprehensively considers the need for the heat spreader to maintain dynamic balance during rotation, the susceptibility of aluminum to oxidation during welding, and the potential for welding slag to clog the injection tank. The resulting circular aluminum dual-phase phase change heat spreader maintains dynamic balance during high-speed rotation. Compared to existing copper or stainless steel materials, it better meets the requirements for heat spreaders under high-speed rotation conditions, offering lower price and weight, thus satisfying the needs of heat spreaders with weight-sensitive requirements.

[0037] Those skilled in the art should understand that the above embodiments are merely for illustrating the present invention and are not intended to limit the scope of the invention. Those skilled in the art can make other changes or modifications based on the above invention, and these changes or modifications still fall within the scope of the present invention.

Claims

1. A circular aluminum two-phase phase change heat spreader, characterized in that: The device includes a heat spreader body, which comprises an upper body and a lower body that cooperate with each other. A first capillary structure is etched on the inner wall of the upper body, and a second capillary structure is etched on the inner wall of the lower body. The first capillary structure and the second capillary structure are in communication. The upper body and the lower body cooperate to form an evaporation chamber, and a working medium is provided in the evaporation chamber. The heat exchange plate body is arranged in a circular shape, and a first through hole is provided at the center of the heat exchange plate body. The center of gravity of the heat exchange plate body coincides with the geometric center of the first through hole. The lower body has a first protrusion at the center hole, and a first groove on the first protrusion. The lower body has a liquid injection groove, one end of which communicates with the first groove, and the other end of which communicates with the evaporation chamber. The evaporation chamber, the liquid injection groove, and the first groove form a closed cavity. The lower body is provided with a main flow channel, and the upper body is provided with a secondary flow channel. The evaporation chamber, the main flow channel, and the secondary flow channel are connected. The lower body has a second protrusion, and the upper body has a second groove. The second protrusion is located below the second groove, and the second protrusion and the second groove form the secondary flow channel. The secondary flow channel divides the main flow channel into a first main flow channel and a second main flow channel. The evaporation chamber, the first main flow channel, the secondary flow channel, and the second main flow channel are connected in sequence.

2. The circular aluminum dual-phase phase change heat spreader according to claim 1, characterized in that: The heat spreader body also includes a plurality of uniformly circumferentially distributed flow guide columns, the two ends of which are vertically connected to the upper body and the lower body respectively; a third capillary structure is etched on the outer surface of the flow guide column, the third capillary structure being connected to the adjacent first capillary structure and second capillary structure; the lower body is provided with a plurality of support columns, the two ends of which are vertically connected to the upper body and the lower body respectively.

3. The circular aluminum two-phase phase change heat spreader according to claim 1, characterized in that: In operation, the temperature distribution plate rotates at a speed of 2000-4000 revolutions per second, and the diameter of the first through hole is greater than the length of the injection groove. The first protrusion is provided with an injection port, which is perpendicular to and communicates with the first groove. The injection groove is provided with one of the following structures: trapezoidal cross-section, rectangular cross-section, circular cross-section, semi-circular cross-section, or elliptical cross-section.

4. A method for manufacturing a circular aluminum two-phase phase change heat spreader, characterized in that: Includes the following steps: S1, the production of the upper body blank and the lower body blank, both of which have a square cross-section structure. The upper body blank has an upper groove, and the lower body blank has a lower groove that matches the upper groove. The upper groove and the lower groove are circular. A first through hole is provided at the center of the upper groove and the lower groove. The center of gravity of the upper body blank and the lower body blank coincides with the geometric center of the first through hole. S2, Etching of the first capillary structure and the second capillary structure: Etching the first capillary structure on the upper tank and etching the second capillary structure on the lower tank. S3, Fabrication of the injection groove: The injection groove is stamped on the lower body blank; a first protrusion is provided at the center hole of the lower body blank, and a first groove is provided on the first protrusion. One end of the injection groove communicates with the first groove, and an injection port is provided on the first protrusion. The injection port is perpendicular to and communicates with the first groove. S4, Welding preparation: Place the carbon rod into the first groove; S5, the upper body blank and the lower body blank are welded together, and the upper body blank and the lower body blank are sealed by first aluminum brazing. After welding, an evaporation chamber is formed. During the first aluminum brazing sealing process, the carbon rod is carbonized into carbon slag. The inner wall of the evaporation chamber is provided with the first capillary structure and the second capillary structure in step S3. S6, Remove the carbon slag, clean the carbon slag in the first groove, and seal the end opening of the first groove; S7, Helium side leak check: Helium is injected into the injection tank and evaporation chamber through the injection port to check for side leaks. If there are side leaks, the leaks are dealt with. If there are no side leaks, the helium check is complete. S8, Liquid medium injection and vacuuming: Liquid medium is injected into the evaporation chamber through the injection port. Then, the evaporation chamber is evacuated, and the injection port is sealed with a second aluminum brazing to maintain a seal between the evaporation chamber and the injection tank, thus obtaining a homogeneous slab. S9. The heat exchange plate blank is machined by milling the upper body blank to the edge of the upper body and the lower body blank to the edge of the lower body to obtain a circular heat exchange plate body. The gravity center of the heat exchange plate body is made to coincide with the geometric center of the first through hole to obtain a circular aluminum two-phase phase change heat exchange plate.

5. The method for manufacturing a circular aluminum two-phase phase change heat spreader according to claim 4, characterized in that: It also includes the following steps: S21, the construction of the secondary flow channel involves setting a second groove on the upper body and a second protrusion on the lower body. The second protrusion is located below the second groove, and the secondary flow channel is formed between the second protrusion and the second groove. S91, before machining the uniformly heated slab, the first protrusion is milled off; The first aluminum brazed seal in S5 is made by diffusion welding, using solder deoxidizer treatment, with a welding temperature of 600-650℃, a welding time of 6-9h, and a welding pressure of 20-40MPa. The second aluminum brazed seal in S9 is produced using a gas-protected atmosphere welding furnace, with solder used, a welding temperature of 550-650℃, and a welding time of 2-3.5 hours. The circular aluminum dual-phase phase change heat spreader is made of pure aluminum or aluminum alloy. The solder comprises 10-15% aluminum and 0.2-0.8% silicon, the percentages being by weight.

6. The method for manufacturing a circular aluminum two-phase phase change heat spreader according to claim 4, characterized in that: The carbon rod contains 35-65% carbon by mass, and the carbon rod is a straight rod that mates with the first groove. Alternatively, the carbon rod may include a baffle, a metal wire perpendicular to the baffle, and a plurality of carbon blocks connected in sequence. The carbon blocks have a second through hole at the center that mates with the metal wire, a third groove at one end of the carbon block, and a third protrusion at the other end.

7. A circular aluminum radiator, characterized in that: It includes a heat spreader and a heat sink, wherein the heat spreader is a circular aluminum dual-phase phase change heat spreader as described in any one of claims 1-3.

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