A phase change cold plate with a gas-liquid separation structure and its heat dissipation method

Abstract

This invention discloses a phase change cooling plate with a gas-liquid separation structure and a heat dissipation method. The phase change cooling plate includes a cover plate, a base plate, an upper capillary layer, and a lower capillary layer. The cover plate is provided with a liquid inlet and an exhaust outlet. The upper capillary layer includes a first substrate and multiple first support pillars, and a connecting pipe is provided on the first substrate. The lower capillary layer includes a second substrate and multiple second support pillars, and a second substrate sidewall is provided with the edge of the second substrate facing upward. A liquid inlet chamber is formed between the upper capillary layer and the cover plate, and the liquid inlet chamber is connected to the liquid inlet. An evaporation chamber is formed between the lower capillary layer and the upper capillary layer, and the evaporation chamber is connected to the connecting pipe of the upper capillary layer. The first substrate, the second substrate, the sidewall of the second substrate, the first support pillars, and the second support pillars are all sintered from copper powder. This invention effectively avoids the obstruction of vapor to liquid reflux, eliminates gas-liquid interference, fundamentally solves problems such as insufficient liquid supply and local dryness, and improves heat exchange efficiency.

Description

Technical Field

[0001] This invention relates to the field of heat dissipation technology, and in particular to a phase change cold plate with a gas-liquid separation structure and its heat dissipation method. Background Technology

[0002] With the rapid development of high-performance computing, artificial intelligence, and data center technologies, the power consumption and heat flux density of devices such as AI acceleration chips and GPU chips in servers continue to increase, posing a severe challenge to heat dissipation technology. Currently, liquid cooling is the main heat dissipation solution for high-power chips. Liquid cooling is further divided into single-phase liquid cooling and two-phase liquid cooling.

[0003] Single-phase liquid cooling involves coolant flowing through a cold plate, utilizing the sensible heat transfer zone to dissipate heat. During this process, the coolant heats up but does not undergo a phase change. However, with the continuous increase in chip heat flux density, single-phase liquid cooling requires a significant increase in coolant flow rate to meet heat dissipation demands. This leads to increased channel pressure drop, higher pumping power consumption, and a sharp decline in energy efficiency. Furthermore, for board-type devices such as OAM cards and PCIe cards, heat is highly concentrated in localized chip areas. Traditional cold plate channel designs struggle to balance overall flow distribution with enhanced heat dissipation for localized hotspots, easily resulting in a situation where "overall temperature is acceptable, but localized areas exceed limits."

[0004] Two-phase liquid cooling utilizes the latent heat of vaporization of the working fluid for heat exchange, and the heat carrying capacity per unit working fluid is much higher than that of single-phase liquid cooling, making it an effective way to solve the problem of heat dissipation at high heat flux densities. However, traditional two-phase cooling plates (e.g., vapor chambers) still have the following shortcomings in practical applications: (1) Gas-liquid interference problem: In traditional heat exchangers, liquid and gaseous working fluids flow in opposite directions in the same cavity. Vapor can easily hinder liquid return, resulting in insufficient liquid supply and local drying, which affects heat dissipation stability.

[0005] (2) Liquid supply drive problem: Heat exchangers usually use capillary structures (such as sintered powder, wire mesh, etc.) to drive the circulation of working fluid. However, there is an inherent contradiction between capillary force and permeability: if the pore size of the capillary structure decreases, the capillary force increases but the flow resistance increases; if the pore size increases, the flow resistance decreases but the capillary force is insufficient. This technical contradiction makes it difficult for existing heat exchangers to achieve both high capillary driving force and low flow resistance.

[0006] (3) Evaporation heat transfer efficiency: Evaporation heat transfer of vapor chambers largely relies on the pool boiling mechanism, that is, the working fluid boils when heated in a static state. During the pool boiling process, bubbles nucleate and grow on the heated surface, and detach by buoyancy after the bubbles grow to a certain size. However, under high heat flux density conditions, the bubble generation rate is too fast, and the liquid on the heated surface cannot be replenished in time, which easily leads to local drying, causing the wall temperature to rise sharply and seriously affecting the heat dissipation stability.

[0007] In view of the above technical problems, this application proposes a phase change cold plate with a gas-liquid separation structure and its heat dissipation method. By avoiding gas-liquid interference through gas-liquid separation design, efficient and stable two-phase heat dissipation is achieved. Summary of the Invention

[0008] In view of the shortcomings of the prior art, the purpose of this invention is to provide a phase change cold plate with a gas-liquid separation structure and its heat dissipation method, aiming to solve the technical problems of gas-liquid mutual interference, unstable liquid supply and low evaporation heat exchange efficiency in the prior art.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: A phase change cold plate with a gas-liquid separation structure includes a cover plate and a base plate. The cover plate has a liquid inlet and a vent. The cover plate and the base plate are sealed together to form an inner cavity. An upper capillary layer and a lower capillary layer are disposed in the inner cavity. The upper capillary layer includes a first substrate and a plurality of first pillars disposed on the first substrate. Each first pillar abuts against the cover plate. A connecting pipe is disposed on the first substrate and communicates with the vent. The upper surface of the connecting pipe abuts against the cover plate. The lower capillary layer includes a second substrate and a plurality of second pillars disposed on the second substrate. Each second pillar abuts against the first substrate. A second substrate sidewall is disposed on the edge of the second substrate and the upper surface of the second substrate sidewall abuts against the first substrate. A liquid inlet chamber is formed between the upper capillary layer and the cover plate and communicates with the liquid inlet. An evaporation chamber is formed between the lower capillary layer and the upper capillary layer and communicates with the connecting pipe of the upper capillary layer. The first substrate, the second substrate, the sidewall of the second substrate, the first pillars, and the second pillars are all sintered from copper powder.

[0010] Furthermore, in the phase change cold plate with gas-liquid separation structure, each of the first pillars has the same specifications and is arranged in an array; each of the second pillars has the same specifications and is arranged in a rectangular array.

[0011] Furthermore, in the phase change cold plate with gas-liquid separation structure, the number of the first support column and the second support column are equal and they are arranged in a one-to-one correspondence, and the diameters of the first support column and the second support column are the same.

[0012] Furthermore, in the phase change cold plate with gas-liquid separation structure, the height of the second support column is greater than the height of the first support column.

[0013] Furthermore, in the phase change cold plate with gas-liquid separation structure, the cover plate is provided with a first enclosure that extends downward and closes at both ends. The inner cavity contour formed by the first enclosure is adapted to the shape of the first substrate of the upper capillary layer. The first substrate of the upper capillary layer is disposed in the first enclosure in an interference fit manner. The bottom plate is provided with a second enclosure that extends upward and closes at both ends. The inner cavity contour formed by the second enclosure is adapted to the shape of the second substrate of the lower capillary layer. The second substrate of the lower capillary layer is disposed in the second enclosure in an interference fit manner.

[0014] Furthermore, in the phase change cold plate with gas-liquid separation structure, an annular flange is provided at the edge of the lower surface of the cover plate, and the lower surface of the annular flange abuts against the upper surface of the first substrate.

[0015] Furthermore, in the phase change cold plate with a gas-liquid separation structure, the liquid inlet is connected to a liquid inlet connector, and the exhaust port is connected to an exhaust connector. This is achieved by providing the liquid inlet connector and the exhaust connector.

[0016] Accordingly, the present invention provides a heat dissipation method based on the phase change cold plate with gas-liquid separation structure described above. Unlike the prior art, the heat dissipation method includes the following steps: S1: The liquid working fluid enters the inlet chamber 300, which is formed by the space between the upper capillary layer and the cover plate, through the inlet. S2: The liquid working fluid, under capillary action, permeates through the first substrate of the upper capillary layer into the evaporation chamber 400 formed by the space between the lower capillary layer and the upper capillary layer; S3: The liquid working fluid absorbs the heat transferred by the bottom plate in the evaporation chamber 400 and undergoes a phase change to become a gaseous working fluid; S4: The gaseous working fluid is discharged through the connecting pipe on the first substrate of the upper capillary layer and the exhaust port on the cover plate; The liquid working medium in the liquid inlet chamber 300 and the gaseous working medium in the evaporation chamber 400 are isolated from each other by the first substrate of the upper capillary layer.

[0017] Furthermore, in step S3 of the heat dissipation method for the phase change cold plate with a gas-liquid separation structure, the liquid working fluid forms a thin liquid film on the surface of the second substrate of the lower capillary layer, and undergoes a phase change through the evaporation of the thin liquid film to transform into a gaseous working fluid.

[0018] Beneficial effects: This invention provides a phase change cold plate with a gas-liquid separation structure and its heat dissipation method, which has the following advantages compared with the prior art: (1) This invention divides the inner cavity of the cold plate into a liquid inlet chamber and an evaporation chamber by setting an upper capillary layer and a lower capillary layer. The liquid working fluid in the liquid inlet chamber and the gaseous working fluid in the evaporation chamber are isolated from each other by the upper capillary layer. Unlike the traditional vapor chamber where the gas and liquid phases flow in opposite directions in the same cavity, the gas-liquid separation design of this invention effectively avoids the obstruction of vapor to liquid reflux, eliminates mutual interference between gas and liquid, fundamentally solves the problems of insufficient liquid supply and local dryness, and improves heat exchange efficiency.

[0019] (2) The upper capillary layer (including the first base plate, the first support column, and the connecting pipe) and the lower capillary layer (including the second substrate, the sidewall of the second substrate, and the second support column) of the present invention are integrally sintered from copper powder to form a continuous porous capillary structure. The first support column not only serves as a support but also acts as a liquid transport channel, rapidly transporting the liquid working fluid from the liquid inlet chamber 300 to the surface of the second substrate. The second support column not only serves as a support but also constitutes a vapor channel to guide the directional discharge of vapor. In addition, the second support column also plays an auxiliary role in heat exchange, which is beneficial to improving the overall heat exchange efficiency. Attached Figure Description

[0020] Figure 1 This is an exploded view of a phase change cold plate with a gas-liquid separation structure.

[0021] Figure 2 Three-dimensional phase change cold plate with gas-liquid separation structure Figure 1 The viewpoint in the image is from a downward angle.

[0022] Figure 3 Three-dimensional phase change cold plate with gas-liquid separation structure Figure 2 The viewpoint in the image is from an angle upwards.

[0023] Figure 4 This is a top view of a phase change cold plate with a gas-liquid separation structure.

[0024] Figure 5 for Figure 4 Sectional view of AA.

[0025] Figure 6 for Figure 5 A magnified view of part S1 in the middle.

[0026] Figure 7 This is a three-dimensional sectional view of a phase change cold plate with a gas-liquid separation structure. The liquid inlet and exhaust outlet are not shown in the figure.

[0027] Figure 8 This is a three-dimensional sectional view of the upper and lower capillary layers.

[0028] Figure 9 for Figure 8 A magnified view of part S2 in the middle.

[0029] Figure 10 This is a three-dimensional view of the cover plate, taken from an upward angle.

[0030] Figure 11 This is a three-dimensional view of the base plate.

[0031] Figure 12 This is a top view of the upper capillary layer.

[0032] Figure 13 This is a three-dimensional view of the lower capillary layer.

[0033] Explanation of reference numerals in the attached figures: 1. Cover plate; 11. First enclosure; 12. Annular flange; 101. Liquid inlet; 102. Vent. 2. Base plate; 21. Second enclosure; 3. Upper capillary layer; 30. First substrate; 31. First support column; 32. Connector; 300. Liquid inlet chamber 300; 4. Lower capillary layer; 40. Second substrate; 41. Second pillar; 42. Second substrate sidewall; 400. Evaporation chamber 400; 51. Liquid inlet connector; 52. Vent connector; H1: Thickness of the first substrate; H2: Height of the first pillar; H3: Thickness of the second substrate; H4: Height of the second pillar; L: Row spacing of the first pillar; W: Column spacing of the first pillar. Detailed Implementation

[0034] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0035] This invention provides a phase change cold plate with a gas-liquid separation structure and its heat dissipation method. The accompanying drawings mainly illustrate structures related to the innovative points of this application; some conventional structures are not specifically shown. The terms "first," "second," etc., used herein are merely different names for different structures for ease of explanation and are not intended to limit the scope of protection of this application. For ease of explanation, directional terms such as "upper," "lower," and "bottom" are unavoidably used herein, but these directional terms are not intended to limit this application, as in practical applications, the phase change cold plate with the gas-liquid separation structure can be placed at different angles. The term "multiple" herein refers to at least two structures; since the specific number of structures referred to is not the innovation point, it is not specifically limited.

[0036] Please refer to the following first. Figures 1 to 6 as well as Figures 11 to 13The phase change cold plate with a gas-liquid separation structure includes a cover plate 1 and a bottom plate 2. The cover plate 1 is provided with a liquid inlet 101 and an exhaust outlet 102. The cover plate 1 and the bottom plate 2 are sealed together to form an inner cavity. An upper capillary layer 3 and a lower capillary layer 4 are provided in the inner cavity. The upper capillary layer 3 includes a first substrate 30 and a plurality of first pillars 31 provided on the first substrate 30. Each first pillar 31 abuts against the cover plate 1. A connecting pipe 32 is provided on the first substrate 30. The connecting pipe 32 communicates with the exhaust outlet 102. The upper surface of the connecting pipe 32 abuts against the cover plate 1. The lower capillary layer 4 includes a second substrate 40 and a plurality of connecting pipes 40 provided on the second substrate 40. The second support pillar 41 on the 40 abuts against the first substrate 30. The edge of the second substrate 40 is provided with a second substrate sidewall 42, and the upper surface of the second substrate sidewall 42 abuts against the first substrate 30. A liquid inlet chamber 300 is formed between the upper capillary layer 3 and the cover plate 1, and the liquid inlet chamber 300 is connected to the liquid inlet 101. An evaporation chamber 400 is formed between the lower capillary layer 4 and the upper capillary layer 3, and the evaporation chamber 400 is connected to the connecting pipe 32 of the upper capillary layer 3. The first substrate 30, the second substrate 40 and the second substrate sidewall 42, the first support pillar 31 and the second support pillar 41 are all sintered from copper powder.

[0037] In actual use, the liquid working fluid enters the inlet chamber 300 through the inlet 101. Under capillary action, it permeates through the upper capillary layer 3 and then travels along the second pillar 41 and the side wall 42 of the second substrate to the second substrate 40, forming a thin liquid film. After absorbing the heat transferred from the base plate 2, it undergoes a phase change and transforms into a gaseous working fluid. The gaseous working fluid is then discharged sequentially through the pipe 32 and the exhaust port 102. Throughout the process, the liquid working fluid in the inlet chamber 300 and the gaseous working fluid in the evaporation chamber 400 are isolated from each other by the upper capillary layer 3, avoiding mutual interference between the gas and liquid and achieving stable two-phase heat dissipation.

[0038] Specifically, the lower surface of the first substrate 30 is flat, and the upper surface of the sidewall 42 of the second substrate is flat. The upper surface of the sidewall 42 of the second substrate and the lower surface of the first substrate 30 form a sealed contact, thus preventing the gaseous working fluid in the evaporation chamber 400 from flowing back into the liquid inlet chamber 300. The lower surface of the cover plate 1 is flat, and the upper surface of the connector 32 is flat. The upper surface of the connector 32 and the lower surface of the cover plate 1 abut against each other to form a sealed contact, thereby preventing the liquid working fluid in the liquid inlet chamber 300 from entering the connector 32.

[0039] Please see Figures 5 to 9In this application, each of the first pillars 31 extends upward, and the upper surface of each first pillar 31 is flat. Each first pillar 31 is flush with the upper surface of the connecting pipe 32, so that the upper surfaces of each first pillar 31 and the connecting pipe 32 abut against the lower surface of the cover plate 1, thus preventing the cover plate 1 from collapsing. Each of the second pillars 41 extends upward, and the upper surface of each second pillar 41 is flat. The upper surface of each second pillar 41 is flush with the upper surface of the side wall 42 of the second substrate, so that the upper surfaces of each second pillar 41 and the side wall 42 of the second substrate abut against the lower surface of the first substrate 30, thereby strengthening the support for the upper capillary layer 3. Since the first pillars 31 are supported between the cover plate 1 and the first substrate 30, and the second pillars 41 are supported between the first substrate 30 and the second substrate 40, a multi-layer support structure is formed. Combined with the supporting effect of the connecting pipe 32 and the supporting effect of the side wall 42 of the second substrate, the overall compressive strength and mechanical strength of the cold plate can be significantly improved, preventing the cover plate 1 and the bottom plate 2 from collapsing. It is evident that the first support 31 and the second support 41 can ensure that the height of the liquid inlet chamber 300 and the evaporation chamber 400 remains constant, avoiding changes in the height of the liquid inlet chamber 300 or the evaporation chamber 400 due to deformation of the cover plate 1 or the bottom plate 2, thereby ensuring the stability of the working fluid flow and the consistency of heat dissipation performance.

[0040] It is particularly important to note that, in addition to their supporting function, the first pillar 31 and the second pillar 41 in this application also have the following functions: (1) Diversion function: The first pillar 31 forms a diversion structure in the liquid inlet chamber 300. When the liquid working fluid flows through the first pillar 31, diversion and remixing occur, which helps the working fluid to be evenly distributed in the liquid inlet chamber 300, thereby improving the uniformity of the permeation of the upper capillary layer 3; (2) Liquid working fluid transport function: Since the second pillar 41 is made of copper powder sintering and has a porous structure, the liquid working fluid in the liquid inlet chamber 300 can enter the interior of the second pillar 41 and be transported downward along the pillar under the action of capillary force. (2) Transport and enter the second substrate 40 from the lower end face of the second pillar 41, which significantly improves the transport efficiency of the liquid working medium from the liquid inlet chamber 300 to the second substrate 40; (3) Vapor guiding effect: Multiple second pillars 41 form a vapor channel, which provides a directional discharge path for vapor, avoiding the increase of flow resistance or local stagnation caused by disordered diffusion of vapor in a large area cavity; (4) Auxiliary heat exchange effect: The surface of the second pillar 41 can be used as an auxiliary heat exchange surface to participate in the heat exchange in the evaporation chamber 400, which increases the effective heat exchange area of ​​the evaporation chamber 400 to a certain extent, which is conducive to further improving the heat exchange efficiency.

[0041] Preferably, each of the first pillars 31 has the same specifications and is arranged in a rectangular array; each of the second pillars 41 has the same specifications and is arranged in a rectangular array. In addition to facilitating the processing of the upper capillary layer 3 and the lower capillary layer 4, this arrangement has the following advantages: (1) Uniform stress: With pillars of the same specifications arranged in a rectangular array, the load borne by each pillar is basically the same, which is conducive to improving the overall stability and compressive strength of the structure; (2) Uniform flow: The pillars arranged in an array form regular flow channels in the cavity, and the flow resistance of the liquid or gaseous working fluid is uniformly distributed when it flows through the pillars, which helps to ensure the uniform distribution of the working fluid in the entire cavity and avoid local flow dead zones or short circuits; (3) Consistent mass and heat transfer: With the same specifications of each pillar, the capillary transmission capacity of the liquid in each pillar is consistent, and the discharge efficiency of the vapor in each channel is also consistent, thereby ensuring that the heat exchange effect is uniform in all parts of the evaporation chamber 400.

[0042] Please see Figure 8 Preferably, the number of first pillars 31 and second pillars 41 are equal and they are arranged in a one-to-one correspondence, and the diameters of the first pillars 31 and second pillars 41 are the same. In a top view, the projection axis of each first pillar 31 coincides with the projection axis of the corresponding second pillar 41. That is, a second pillar 41 is coaxially arranged directly below each first pillar 31. The following advantages are provided by this configuration: (1) The first pillar 31 and the second pillar 41 are coaxially aligned, so that the supporting force of the first pillar 31 and the second pillar 41 is transmitted along the same straight line, which reduces bending stress and improves the stability and compressive strength of the structure; (2) After the liquid working medium passes through the first substrate 30 from the area of ​​the first pillar 31, it can directly enter the second pillar 41 directly below, so that the transmission path of the liquid working medium is the shortest straight distance, which is conducive to improving the liquid supply efficiency and ensuring efficient heat exchange; (3) The capillary transmission capacity of the pillar is related to its diameter. Since the first pillar 31 and the second pillar 41 have the same diameter, the capillary driving force of the liquid in the first pillar 31 is matched with the capillary driving force in the second pillar 41, ensuring the continuous and stable transmission of the liquid from the liquid inlet chamber 300 to the evaporation chamber 400.

[0043] Furthermore, the height of the second support pillar 41 is greater than the height of the first support pillar 31. The height of the liquid inlet chamber 300 is equal to the height of the first support pillar 31, and the height of the evaporation chamber 400 is equal to the height of the second support pillar 41. Therefore, the height of the evaporation chamber 400 is greater than the height of the liquid inlet chamber 300. Since the evaporation chamber 400 needs to provide sufficient flow space for vapor discharge while avoiding interference of vapor with liquid transport, its height is usually greater than that of the liquid inlet chamber 300. Therefore, the height of the second support pillar 41 is limited to be greater than the height of the first support pillar 31, which meets the functional requirements of the two chambers.

[0044] Please see Figures 5 to 7Furthermore, the first capillary layer and the second capillary layer can be disposed in the cavity enclosed by the cover plate 1 and the bottom plate 2 in the following manner: the cover plate 1 is provided with a first enclosure 11 that extends downward and closes at both ends, the inner cavity outline formed by the first enclosure 11 is adapted to the shape of the first substrate 30 of the upper capillary layer 3, and the first substrate 30 of the upper capillary layer 3 is disposed in the first enclosure 11 in an interference fit manner (that is, the outer wall of the first substrate is tightly fitted with the inner wall of the first enclosure); the bottom plate 2 is provided with a second enclosure 2121 that extends upward and closes at both ends, the inner cavity outline formed by the second enclosure 21 is adapted to the shape of the second substrate 40 of the lower capillary layer 4, and the second substrate 40 of the lower capillary layer 4 is disposed in the second enclosure 21 in an interference fit manner (that is, the outer wall of the second substrate is tightly fitted with the inner wall of the second enclosure). In actual assembly, this setup has the following advantages: (1) Simplified assembly: During the assembly process, the first enclosure 11 and the second enclosure 21 act as guides, and the upper capillary layer 3 and the lower capillary layer 4 can be accurately positioned without complicated alignment; (2) The first enclosure 11 and the second enclosure 21 act as limiters, which can fix the upper capillary layer 3 and the lower capillary layer 4 in the predetermined position, preventing the upper capillary layer 3 and the lower capillary layer 4 from being displaced due to vibration or thermal expansion during use.

[0045] As a preferred embodiment, the second substrate sidewall 42 extends upward from the outermost edge of the second substrate 40, so the edge of the second substrate sidewall 42 is flush with the edge of the second substrate 40. The significance of this arrangement is: (1) maximizing the volume of the evaporation chamber 400; since the second substrate sidewall 42 is located at the outermost edge of the second substrate 40, the internal space formed by its enclosure is maximized, thereby effectively increasing the volume of the evaporation chamber 400, which is conducive to the full phase change of the working fluid and vapor diffusion, and improving heat dissipation efficiency; (2) improving assembly stability; the second substrate sidewall 42 and the second enclosure 21 on the base plate 2 adopt an interference fit (i.e., the outer wall of the second substrate sidewall and the inner wall of the second enclosure are tightly fitted), and the edge of the second substrate sidewall 42 is flush with the edge of the second substrate 40, so that the lower capillary layer 4 and the second enclosure 21 are in closer contact. After assembly, the lower capillary layer 4 is firmly limited in the base plate 2, and it is not easy to loosen or shift, thus improving the overall stability of the structure.

[0046] Please see Figure 10 Furthermore, an annular flange 12 is provided at the edge of the lower surface of the cover plate 1, and the lower surface of the annular flange 12 abuts against the upper surface of the first substrate 30. Specifically, the upper surface of the first substrate 30 is flat, the lower surface of the annular flange 12 is flat, and the lower surface of the annular flange 12 forms a sealing contact with the upper surface of the first substrate 30 to prevent the liquid working fluid in the liquid inlet cavity from flowing outward from the edge of the first substrate 30.

[0047] It is understood that, as a preferred embodiment, the first substrate 30, the annular flange 12, the second substrate 40, the sidewall 42 of the second substrate, the first enclosure 11, and the second enclosure 21 are all rectangular. Rectangular structures are easy to process and manufacture, which helps reduce production costs and improve processing efficiency. Of course, the above structures are not limited to rectangles; they can also be circular, elliptical, or other regular or irregular shapes. As long as the basic function of gas-liquid separation in this invention is achieved and the technical effects of this invention are realized, these alternative shapes all fall within the protection scope of this invention.

[0048] As a preferred embodiment, the diameter of the first support column 31 is 4-5 mm, and the height H2 of the first support column is 2-3 mm; the row spacing L of the first support column 31 ranges from 7-9 mm, and the column spacing W of the first support column 31 ranges from 8-10 mm (e.g., ...). Figure 11 As shown), the row spacing and column spacing of the second support 41 are the same as those of the first support 31; the diameter of the second support 41 is 4~5mm, and the height H4 of the second support 41 is 8~10mm (as shown). Figure 9 (As shown). In this invention, a design with a larger support diameter and a larger support spacing is adopted. The diameters of the first support 31 and the second support 41 are both 4~5mm, which can significantly improve the compressive strength between the cover plate 1 and the base plate 2 and prevent collapse and deformation. The larger row and column spacing of the second support 41 provides a spacious channel for steam discharge, reduces steam flow resistance, and facilitates the rapid discharge of steam from the evaporation chamber 400 to the exhaust port 102. The height of the second support 41 is 8~10mm, which gives the evaporation chamber 400 sufficient space, which is conducive to the formation of a thin liquid film and the diffusion of steam, while providing sufficient surface area for the surface of the second support 41 to participate in heat exchange.

[0049] In actual manufacturing, the upper capillary layer 3 and the lower capillary layer 4 are formed by sintering copper powder. Specifically, copper powder is filled into a pre-set mold and sintered at high temperature to form the upper capillary layer 3 having a first substrate 30, a first support column 31, and a connecting pipe 32, and the lower capillary layer 4 having a second substrate 40, a second support column 41, and a second substrate sidewall 42. The cover plate 1 and the base plate 2 are respectively processed from aluminum alloy. During assembly, the upper capillary layer 3 is inserted into the cover plate 1, so that the first support column 31 abuts against the lower surface of the cover plate 1, and the connecting pipe 32 is aligned with the exhaust port 102; the lower capillary layer 4 is inserted into the base plate 2, so that the second substrate sidewall 42 faces upward and the second support column 41 faces upward. Then the base plate 2 and the cover plate 1 are aligned and closed, so that the upper surface of the second substrate sidewall 42 abuts against the lower surface of the first substrate 30, and the upper end of the second support column 41 abuts against the lower surface of the first substrate 30. The alignment method can employ a structure using positioning holes and positioning pins, or other known positioning methods, which will not be elaborated here. After alignment, the cover plate 1 and the base plate 2 are clamped and fixed using a fixture, and then the connection between the cover plate 1 and the base plate 2 is welded to complete the manufacturing of the phase change cold plate with the gas-liquid separation structure. It should be noted that the fixture is an auxiliary tooling in the welding process and is not within the scope of protection of this invention, therefore it is not specifically limited.

[0050] Preferably, the copper powder particle size of the upper capillary layer 3 is 120-200 mesh, the porosity is 35%-50%, and the thickness H1 of the first substrate 30 is 2-3 mm; the copper powder particle size of the lower capillary layer 4 is 120-200 mesh, the porosity is 35%-50%, and the thickness H3 of the second substrate 40 is 0.3-0.5 mm (e.g., ...). Figure 9 (As shown). The copper powder with a particle size of 120-200 mesh achieves a good balance between capillary force and permeability, taking into account both working fluid transport efficiency and capillary driving capability. After sintering, the copper powder forms a porous capillary structure with a porosity of 35% to 50%. Among them, the lowest thermal resistance value can be obtained when the porosity is around 50%. The first substrate 30 is thicker than the second substrate 40, which on the one hand provides sufficient mechanical strength to support the cover plate 1 against the cavity pressure; on the other hand, it can store more liquid working fluid, playing a buffering role and improving the continuity and stability of liquid supply. The second substrate 40 is thinner than the first substrate 30, which helps to shorten the liquid transport path to the evaporation surface, reduce thermal resistance, and achieve efficient thin liquid film evaporation.

[0051] Furthermore, the liquid inlet 101 is connected to a liquid inlet connector 51, and the vent 102 is connected to a vent connector 52. The liquid inlet connector 51 is used to connect to an external liquid supply pipeline, and the vent connector 52 is used to connect to an external vent pipeline. By providing the liquid inlet connector 51 and the vent connector 52, the cold plate can be quickly connected to the external pipeline, improving assembly efficiency and sealing reliability. As a preferred embodiment, the liquid inlet connector 51 is fixed to the liquid inlet 101 by brazing, and the vent connector 52 is fixed to the vent 102 by brazing. Brazing connection has the advantages of high connection strength, good sealing performance, and strong pressure resistance, ensuring that the liquid inlet connector 51 and the vent connector 52 do not leak during long-term use.

[0052] In actual use, the inlet end of the liquid inlet connector 51 is connected to the liquid supply pipeline (not shown in the figure), and liquid working fluid is injected into the liquid inlet chamber 300. The outlet end of the exhaust connector 52 is connected to the exhaust pipeline (not shown in the figure), and the lower surface of the base plate 2 is placed against the heat source to be cooled (such as a chip, not shown in the figure). The liquid working fluid enters the liquid inlet connector 51 from the external liquid supply pipeline and then enters the liquid inlet chamber 300 through the liquid inlet 101. The vapor in the evaporation chamber 400 is discharged to the external pipeline in sequence through the connecting pipe 32, the exhaust port 102, and the exhaust connector 52. The external pipelines such as the liquid inlet pipeline and the exhaust pipe are not shown in the figure because these external pipelines are not within the protection scope of this invention, and therefore are not specifically drawn or limited.

[0053] Accordingly, this application also provides a heat dissipation method based on the phase change cold plate with gas-liquid separation structure described above, the method comprising the following steps: S1: The liquid working fluid enters the inlet chamber 300, which is formed by the space between the upper capillary layer 3 and the cover plate 1, through the inlet 101; S2: The liquid working fluid, under capillary action, permeates through the first substrate 30 of the upper capillary layer 3 into the evaporation chamber 400 formed by the space between the lower capillary layer 4 and the upper capillary layer 3; S3: The liquid working fluid absorbs the heat transferred by the bottom plate 2 in the evaporation chamber 400 and undergoes a phase change to become a gaseous working fluid; S4: The gaseous working fluid is discharged through the pipe 32 on the first substrate 30 of the upper capillary layer 3 and the exhaust port 102 on the cover plate 1; The liquid working medium in the liquid inlet chamber 300 and the gaseous working medium in the evaporation chamber 400 are isolated from each other by the first substrate 30 of the upper capillary layer 3.

[0054] Further, in step S3, the liquid working fluid forms a thin liquid film on the surface of the second substrate 40 of the lower capillary layer 4, and undergoes a phase change through evaporation of the thin liquid film, transforming into a gaseous working fluid. The "thin liquid film" refers to a uniformly thin liquid film formed on the surface of the second substrate 40 by the liquid working fluid spreading under capillary force. The thickness of this thin liquid film is typically in the micrometer range (e.g., 10-200 micrometers), and its thermal resistance is much lower than that of the liquid layer in pool boiling. Through the thin liquid film evaporation method, the thermal resistance of evaporative heat transfer can be significantly reduced, the heat transfer coefficient can be improved, and efficient and stable two-phase heat dissipation can be achieved, effectively avoiding the localized drying problem caused by bubble retention in traditional pool boiling.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. It is understood that those skilled in the art can make equivalent substitutions or modifications based on the technical solution and inventive concept of the present invention, and all such modifications or substitutions should fall within the protection scope of the present invention.

Claims

1. A phase change cold plate with a gas-liquid separation structure, comprising a cover plate and a bottom plate, wherein the cover plate is provided with a liquid inlet and a vent, characterized in that: The cover plate and the bottom plate are sealed together to form an inner cavity, in which an upper capillary layer and a lower capillary layer are disposed. The upper capillary layer includes a first substrate and a plurality of first pillars disposed on the first substrate. Each first pillar abuts against the cover plate. A connecting pipe is disposed on the first substrate, which communicates with an exhaust port. The upper surface of the connecting pipe abuts against the cover plate. The lower capillary layer includes a second substrate and a plurality of second pillars disposed on the second substrate. Each second pillar abuts against the first substrate. A second substrate sidewall is disposed on the edge of the second substrate, and the upper surface of the second substrate sidewall abuts against the first substrate. A liquid inlet chamber is formed between the upper capillary layer and the cover plate, and the liquid inlet chamber communicates with a liquid inlet. An evaporation chamber is formed between the lower capillary layer and the upper capillary layer, and the evaporation chamber communicates with the connecting pipe of the upper capillary layer. The first substrate, the second substrate, the sidewalls of the second substrate, the first pillars, and the second pillars are all sintered from copper powder.

2. The phase change cold plate with a gas-liquid separation structure according to claim 1, characterized in that: All first pillars are of the same specification and are arranged in an array; all second pillars are of the same specification and are arranged in a rectangular array.

3. The phase change cold plate with a gas-liquid separation structure according to claim 2, characterized in that: The number of first and second pillars is equal and they are set in a one-to-one correspondence. The diameter of the first and second pillars is the same.

4. The phase change cold plate with a gas-liquid separation structure according to claim 3, characterized in that: The height of the second pillar is greater than the height of the first pillar.

5. The phase change cold plate with a gas-liquid separation structure according to claim 1, characterized in that: The cover plate has a first enclosure that extends downward and closes at both ends. The inner cavity contour formed by the first enclosure is adapted to the shape of the first substrate of the upper capillary layer. The first substrate of the upper capillary layer is disposed in the first enclosure in an interference fit manner. The bottom plate has a second enclosure that extends upward and closes at both ends. The inner cavity contour formed by the second enclosure is adapted to the shape of the second substrate of the lower capillary layer. The second substrate of the lower capillary layer is disposed in the second enclosure in an interference fit manner.

6. The phase change cold plate with a gas-liquid separation structure according to claim 5, characterized in that: An annular flange is provided at the edge of the lower surface of the cover plate, and the lower surface of the annular flange abuts against the upper surface of the first substrate.

7. The phase change cold plate with a gas-liquid separation structure according to claim 1, characterized in that: The inlet is connected to an inlet connector, and the outlet is connected to an outlet connector. This is achieved by providing both the inlet and outlet connectors.

8. A heat dissipation method based on a phase change cold plate with a gas-liquid separation structure according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1: The liquid working fluid enters the inlet chamber 300, which is formed by the space between the upper capillary layer and the cover plate, through the inlet. S2: The liquid working fluid, under capillary action, permeates through the first substrate of the upper capillary layer into the evaporation chamber 400 formed by the space between the lower capillary layer and the upper capillary layer; S3: The liquid working fluid absorbs the heat transferred by the bottom plate in the evaporation chamber 400 and undergoes a phase change to become a gaseous working fluid; S4: The gaseous working fluid is discharged through the connecting pipe on the first substrate of the upper capillary layer and the exhaust port on the cover plate; The liquid working medium in the liquid inlet chamber 300 and the gaseous working medium in the evaporation chamber 400 are isolated from each other by the first substrate of the upper capillary layer.

9. The heat dissipation method of the phase change cold plate with gas-liquid separation structure according to claim 8, characterized in that: In step S3, the liquid working fluid forms a thin liquid film on the surface of the second substrate of the lower capillary layer, and undergoes a phase change through the evaporation of the thin liquid film to transform into a gaseous working fluid.

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