A two-phase cold plate employing sintered metal powder layers and a method of making the same

Abstract

The application relates to the technical field of electronic equipment cooling, in particular to a two-phase cold plate adopting a sintered metal powder layer and a preparation method thereof. The two-phase cold plate comprises a heat exchange plate, a partition plate and a cover plate. An evaporation cavity is formed between the heat exchange plate and the partition plate, a condensation cavity is formed between the partition plate and the cover plate, and a through hole is formed in the partition plate and communicates the evaporation cavity and the condensation cavity. A sintered metal powder layer is fixed on one side of the heat exchange plate inside the evaporation cavity and is used for providing a nucleate boiling vaporization core and realizing uniform distribution of a working medium. The preparation method comprises part pretreatment, sintered metal powder layer preparation, assembly and sealed connection, and air tightness detection and working medium filling. The sintered metal powder layer strengthens nucleate boiling heat exchange, and the through hole realizes two-phase circulation of steam transportation and liquid working medium backflow, so that the critical heat flux density and the heat exchange efficiency can be effectively improved, and the two-phase cold plate is suitable for high-power-density chip heat dissipation.

Description

Technical Field

[0001] This application relates to the field of electronic device cooling technology, specifically to a two-phase cold plate employing a sintered metal powder layer and its preparation method. Background Technology

[0002] With the rapid development of artificial intelligence technology and high-performance computing, the power consumption of a single chip has exceeded 1000W, and the local heat flux density exceeds 300W / cm². High-power density chips, represented by AI server GPUs, high-performance computing CPUs, and power semiconductor devices, place extremely stringent requirements on heat dissipation systems. Traditional single-phase liquid cooling technology relies on the sensible heat of the liquid working fluid for heat transfer, and its heat transfer coefficient is approaching its theoretical limit, making it difficult to meet the heat dissipation requirements of heat flux densities exceeding 100W / cm².

[0003] Currently, two-phase cold plates utilize the latent heat of phase change of the working fluid for heat transfer, which is one of the most effective solutions for heat dissipation in ultra-high power density applications. However, traditional two-phase cold plates often employ simple cavity structures or single-wire meshes for gas-liquid separation. The vapor and liquid interfere with each other within the cavity, hindering liquid reflux and causing localized drying on the evaporation surface. Furthermore, ordinary smooth surfaces or microchannel structures have a limited number of vaporization nuclei, resulting in high initial superheat of nucleated boiling, low heat transfer coefficients under low power conditions, and a tendency for flow instability, making it difficult to maintain high-efficiency heat transfer performance over a wide power range.

[0004] Therefore, how to achieve efficient gas-liquid separation while enhancing evaporative heat exchange performance, and solve the problem of low heat exchange performance caused by insufficient vaporization cores, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In order to achieve efficient gas-liquid separation while enhancing evaporative heat transfer performance and solve the problem of low heat transfer performance caused by insufficient vaporization core, this application provides a two-phase cold plate with a sintered metal powder layer and its preparation method.

[0006] This application provides a two-phase cold plate employing a sintered metal powder layer and its preparation method, using the following technical solution: First aspect A two-phase cold plate employing a sintered metal powder layer includes a heat exchange plate, a partition plate sealed to the heat exchange plate, and a cover plate sealed to the partition plate; an evaporation chamber is formed between the heat exchange plate and the partition plate, and a condensation chamber is formed between the partition plate and the cover plate; the partition plate has several through holes communicating with the evaporation chamber and the condensation chamber; the evaporation chamber is provided with a working fluid inlet, and the condensation chamber is provided with a working fluid outlet, the working fluid inlet and the working fluid outlet being arranged relatively far apart; a sintered metal powder layer is fixed on one side of the heat exchange plate located inside the evaporation chamber.

[0007] By adopting the above technical solution, the heat exchange plate, baffle, and cover plate are stacked and sealed in sequence to form a sealed plate structure with an evaporation chamber and a condensation chamber. The through holes on the baffle connect the evaporation chamber and the condensation chamber to realize the two-phase internal circulation of the working fluid. The relatively far arrangement of the working fluid inlet and outlet prolongs the flow path of the working fluid in the two-phase cold plate and improves the heat exchange efficiency. The sintered metal powder layer forms a metallurgical bond with the heat exchange plate through the sintering process. Its numerous microporous structures constitute stable vaporization nuclei, allowing the liquid working fluid to undergo nucleation boiling at a relatively low superheat, significantly improving the heat exchange efficiency. At the same time, the capillary force of the sintered metal powder layer ensures that the liquid working fluid is evenly spread on the evaporation surface, avoiding local drying, thus effectively dealing with heat dissipation scenarios with high heat flux density.

[0008] Furthermore, the heat exchange plate includes a heat exchange base plate, on which a plurality of uniformly distributed heat exchange fins are arranged on one side located inside the evaporation chamber. The heat exchange fins are arranged along the working fluid inlet toward the working fluid outlet, and the sintered metal powder layer is disposed on the side of the heat exchange fins.

[0009] By adopting the above technical solution, the heat exchange fins uniformly and densely distributed on the heat exchange base plate are arranged along the mainstream direction of the working fluid, significantly expanding the effective heat exchange area within the evaporation chamber. A sintered metal powder layer covers the sides of the heat exchange fins, making each fin a reinforced boiling surface with a porous coating, increasing the density of vaporization nuclei. The area expansion effect of the heat exchange fins and the nucleation boiling enhancement effect of the sintered metal powder layer work synergistically to significantly improve the heat transfer coefficient compared to ordinary smooth surfaces.

[0010] Furthermore, the heat exchange fins are provided with a number of equally spaced slots, and all the slots on the heat exchange fins form a straight groove along the working fluid inlet toward the working fluid outlet.

[0011] By adopting the above technical solution, the equally spaced slots are aligned along the working fluid inlet towards the working fluid outlet to form a straight channel that runs through the entire flow direction of the evaporation chamber. The straight channel provides a low-resistance flow path for the liquid working fluid and steam to pass through the evaporation chamber, solving the flow blockage problem that may be caused by the uniform and dense distribution of heat exchange fins, and allowing the working fluid to flow smoothly through the evaporation chamber along the flow direction. At the same time, the equally spaced slots help to homogenize the pressure distribution in the evaporation chamber, promote the uniform distribution of the working fluid to each heat exchange fin area, and avoid local overheating or insufficient liquid supply.

[0012] Furthermore, a reflux groove connecting the evaporation chamber and the condensation chamber is provided on the side of the partition away from the working fluid inlet.

[0013] By adopting the above technical solution, the reflux tank provides an independent liquid-phase reflux path for the condensed liquid working fluid, complementing the reflux function of the through-hole. The reflux tank is located on the side furthest from the working fluid inlet, which facilitates the formation of a complete circulation path. After the liquid working fluid enters the evaporation chamber from the working fluid inlet and evaporates, the vapor rises to the condensation chamber through the through-hole. After condensation, the liquid working fluid flows back to the far end of the evaporation chamber through the reflux tank, replenishing the working fluid towards the inlet under capillary force and flow drive, forming a closed internal circulation. The reflux tank supplements the liquid-phase reflux capacity of the through-hole, preventing condensate from accumulating in the condensation chamber and ensuring a continuous supply of liquid working fluid to the sintered metal powder layer in the evaporation chamber, avoiding heat transfer deterioration caused by localized drying.

[0014] Furthermore, a first recessed cavity is formed on the lower surface of the partition plate, and the inner side of the first recessed cavity is sealed with the upper surface of the heat exchange plate to form the evaporation cavity. The working fluid inlet is located on the side of the partition plate, communicating with the first recessed cavity, and a working fluid input pipe is fixedly and sealed inside the working fluid inlet.

[0015] By adopting the above technical solution, the first recessed cavity on the lower surface of the partition precisely defines the spatial shape and volume of the evaporation chamber, facilitating the control of the working fluid storage and evaporation space. The working fluid inlet is located on the side of the partition, connecting to the first recessed cavity, and is connected to the external liquid supply system via a working fluid input pipe. The working fluid input pipe is sealed to the partition through brazing or welding processes, ensuring the reliability of the liquid working fluid supply and the system's airtightness.

[0016] Furthermore, a second recessed cavity is formed on the lower surface of the cover plate, and the inner side of the second recessed cavity is sealed with the upper surface of the partition plate to form the condensation cavity. The working fluid outlet is located on the side of the cover plate in connection with the second recessed cavity, and a working fluid output pipe is fixedly and sealed inside the working fluid outlet.

[0017] By adopting the above technical solution, the second recessed cavity on the lower surface of the cover plate precisely defines the spatial shape and volume of the condensation chamber, providing sufficient heat exchange space for steam condensation. The working fluid outlet is located on the side of the cover plate, connecting to the second recessed cavity. It is connected to an external condensation system or circulation pipeline through a working fluid output pipe. The working fluid output pipe is sealed to the cover plate by brazing or welding, ensuring the reliability of the working fluid discharge after condensation and the system's airtightness.

[0018] Furthermore, the sintered metal powder layer includes a first porous layer and a second porous layer. The first porous layer and the second porous layer are fixed to the upper surface of the heat exchange plate by a sintering process. The first porous layer is close to the upper surface of the heat exchange plate, and the pores of the first porous layer are smaller than the pores of the second porous layer.

[0019] By adopting the above technical solution, the first porous layer, located near the surface of the heat exchange plate, generates a strong capillary driving force through its smaller pores, continuously adsorbing the liquid working fluid from the liquid region of the evaporation chamber to the surface of the heat exchange plate. Simultaneously, the numerous micropores provide abundant vaporization nuclei, enabling nucleation boiling of the liquid working fluid at relatively low superheat. The second porous layer, located outside the first porous layer, provides a low-resistance escape channel for steam through its larger pores. After steam is generated in the first porous layer, it rapidly diffuses into the main space of the evaporation chamber through the large pores of the second porous layer, preventing steam from accumulating in the porous layer and forming a vapor film that would block the supply of liquid working fluid. This dual-porous-layer structure achieves functional separation between the inward supply of the liquid phase and the outward discharge of the vapor phase, effectively avoiding mutual interference between the reverse vapor-liquid flows and significantly improving the critical heat flux density.

[0020] Furthermore, an evaporation tank is provided on the side of the sintered metal powder layer away from the heat exchange plate, and the length direction of the evaporation tank intersects the direction of the working fluid inlet toward the working fluid outlet.

[0021] By adopting the above technical solution, the evaporation tank located on the side of the sintered metal powder layer away from the heat exchange plate increases the contact area between the sintered metal powder layer and the liquid working fluid, thereby increasing the evaporation heat exchange area. Since the length direction of the evaporation tank intersects with, rather than is parallel to, the direction from the working fluid inlet to the working fluid outlet, the working fluid is guided by the evaporation tank during flow, generating lateral flow disturbances. This enhances the uniformity of heat exchange within the evaporation chamber and prevents the working fluid from flowing rapidly through the evaporation area along the mainstream direction without sufficient heat exchange.

[0022] Furthermore, a metal mesh layer is fixedly installed on the upper surface of the partition. The metal mesh layer is formed by stacking and sintering several layers of metal wire mesh, and the metal mesh layer forms a uniformly dense steam passage.

[0023] By adopting the above technical solution, the metal mesh layer on the upper surface of the partition plate is formed by sintering several layers of metal wire mesh to create a uniformly dense steam passage, the equivalent pore size of which is much smaller than the diameter of the through holes. When steam rises from the evaporation chamber through the through holes, the metal mesh layer intercepts and filters the tiny droplets entrained in the steam, achieving a second-stage gas-liquid separation. The intercepted droplets converge on the surface of the metal mesh layer and flow back to the evaporation chamber through the through holes under gravity, while the purified steam enters the condensation chamber for condensation. The metal mesh layer and the through holes constitute a two-stage composite gas-liquid separation structure. The through holes achieve the first-stage separation to block large droplets and guide the steam upward, while the metal mesh layer achieves the second-stage separation to filter tiny droplets. The synergistic effect of the two-stage separation ensures that the steam entering the condensation chamber has high quality, effectively avoiding the problem of insufficient liquid supply to the evaporation chamber caused by the liquid working fluid being carried into the condensation chamber by the steam.

[0024] Secondly, a method for preparing a two-phase cold plate using a sintered metal powder layer as described in the first aspect includes the following steps: Step S1, Part pretreatment: Pretreatment of the upper surface of the heat exchange plate; Step S2, preparing a sintered metal powder layer: install a tooling mold in the corresponding area of ​​the evaporation chamber on the upper surface of the heat exchange plate, then evenly spread the metal powder in the tooling mold, and perform sintering treatment under a protective atmosphere to form a metallurgical bond between the metal powder particles and between the metal powder and the heat exchange plate, thus forming a sintered metal powder layer. Step S3, Assembly and Sealing Connection: Assemble and seal the partition and cover plate sequentially onto the heat exchange plate; Step S4, airtightness test and working fluid injection: Perform airtightness test and working fluid injection on the two-phase cold plates after sealing connection.

[0025] By adopting the above technical solution, step S1 involves ultrasonic cleaning and acid pickling pretreatment of the heat exchange plate surface to remove surface oil and oxide layers, ensuring a good metallurgical bond between the sintered metal powder layer and the heat exchange plate, thereby improving the bonding strength and thermal conductivity. Step S2 involves sintering under a protective atmosphere, allowing metallurgical bonding to form between metal powder particles and between the metal powder and the heat exchange plate through solid-state diffusion, resulting in a sintered metal powder layer with numerous microporous vaporization nuclei and capillary force on the heat exchange plate surface. Step S3 uses vacuum brazing or diffusion welding to seal the heat exchange plate, partition, and cover plate into a single unit, ensuring reliable sealing between the three layers, high joint strength, and good airtightness. Step S4 involves injecting working fluid under vacuum conditions to remove air and non-condensable gases from the cavity, preventing the accumulation of non-condensable gases in the condensation cavity and reducing condensation heat exchange efficiency, thus ensuring stable operation of the two-phase cycle.

[0026] The two-phase cold plate with sintered metal powder layer and its preparation method provided in this application have at least the following advantages compared with the prior art: This application fixes a sintered metal powder layer on one side of the heat exchange plate inside the evaporation chamber. The numerous microporous structures in the sintered metal powder layer form a stable vaporization nucleus, allowing the liquid working fluid to undergo nucleation boiling at a relatively low superheat. Utilizing the latent heat of phase change, the heat transfer coefficient can reach 10-100 times that of single-phase liquid cooling, effectively handling high heat flux density heat dissipation scenarios. At the same time, the capillary force of the sintered metal powder layer ensures that the liquid working fluid is evenly spread on the evaporation surface, preventing localized drying.

[0027] This application sets a sintered metal powder layer on the surface of the heat exchange fins. The area expansion effect of the heat exchange fins and the nucleation boiling enhancement effect of the sintered metal powder layer work together to significantly improve the heat transfer coefficient compared with ordinary smooth surfaces. The slots opened on the heat exchange fins form straight grooves that penetrate the evaporation chamber, which solves the flow blockage problem caused by dense fins and promotes uniform distribution of the working fluid.

[0028] This application adopts a dual-pore layer structure. The small pores in the first pore layer generate strong capillary driving force and provide abundant vaporization nuclei, while the large pores in the second pore layer provide a low-resistance escape channel for steam. This achieves functional separation between the inward supply of liquid phase and the outward discharge of vapor phase, effectively avoiding mutual interference between the reverse flow of vapor and liquid, and significantly improving the critical heat flux density.

[0029] This application provides an evaporation tank on the surface of the sintered metal powder layer. The length direction of the evaporation tank intersects with the mainstream direction of the working fluid, which increases the evaporation heat transfer area and generates lateral flow disturbance, thereby enhancing the uniformity of heat transfer in the evaporation chamber.

[0030] This application provides a metal mesh layer on the upper surface of the partition plate, which together with the through holes forms a two-stage composite gas-liquid separation structure, ensuring that the quality of the steam entering the condensation chamber is high and effectively preventing the liquid working fluid from being carried away by the steam, resulting in insufficient liquid supply to the evaporation chamber.

[0031] This application provides a reflux trough on the side of the partition away from the working fluid inlet, providing an independent liquid phase reflux path for the condensed liquid working fluid. This complements the reflux function of the through hole, preventing the condensate from accumulating in the condensation chamber and ensuring that the sintered metal powder layer in the evaporation chamber is continuously supplied with liquid working fluid. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of this application.

[0033] Figure 2 This is an exploded view of the structure of Embodiment 1 of this application.

[0034] Figure 3 This is a schematic diagram of the internal structure of Embodiment 1 of this application.

[0035] Figure 4 This is a schematic diagram of the heat exchange plate in Embodiment 1 of this application.

[0036] Figure 5 This is a schematic diagram of the partition structure in Embodiment 1 of this application.

[0037] Figure 6 This is a schematic diagram of the cover plate in Embodiment 1 of this application.

[0038] Figure 7 yes Figure 2 Enlarged schematic diagram of Part I of the structure.

[0039] Figure 8 yes Figure 3 Enlarged schematic diagram of Part II of the structure.

[0040] Figure 9 This is a schematic diagram of the tooling mold in the usage state of Embodiment 2 of this application.

[0041] Figure 10 This is a schematic diagram of the disassembled state of the tooling mold in Embodiment 2 of this application.

[0042] Explanation of reference numerals in the attached drawings: 100, heat exchange plate; 101, heat exchange base plate; 102, heat exchange fins; 103, slot; 104, straight through slot; 200, partition plate; 201, through hole; 202, reflux slot; 203, first recessed cavity; 204, working fluid inlet pipe; 300, cover plate; 301, second recessed cavity; 302, working fluid outlet pipe; 400, evaporation cavity; 401, working fluid inlet; 500, condensation cavity; 501, working fluid outlet; 600, sintered metal powder layer; 601, first porous layer; 602, second porous layer; 603, evaporation tank; 700, metal mesh layer; 701, metal wire mesh; 702, steam passage; 800, tooling mold; 801, frame tooling; 802, strip tooling. Detailed Implementation

[0043] The following combination Figures 1-10 This application will be described in further detail.

[0044] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0045] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0046] This application discloses a two-phase cold plate using a sintered metal powder layer and its preparation method.

[0047] Example 1 Please refer to the above as well. Figures 1 to 8 In one embodiment of this application, a two-phase cold plate employing a sintered metal powder layer includes a heat exchange plate 100, a partition plate 200, and a cover plate 300.

[0048] like Figure 1 and Figure 2 As shown, the upper surface of the heat exchange plate 100 is sealed with a partition plate 200, and the upper surface of the partition plate 200 is sealed with a cover plate 300. The heat exchange plate 100, the partition plate 200 and the cover plate 300 are stacked from bottom to top and sealed together by vacuum brazing or diffusion welding to form an integrated sealed plate structure.

[0049] An evaporation chamber 400 is provided between the heat exchange plate 100 and the partition plate 200, and a condensation chamber 500 is provided between the partition plate 200 and the cover plate 300. The evaporation chamber 400 is used for the evaporation and heat absorption of the liquid working fluid, and the condensation chamber 500 is used for the condensation and heat release of the gaseous working fluid. The evaporation chamber 400 and the condensation chamber 500 constitute the two core working chambers of the two-phase cold plate.

[0050] The partition 200 has several through holes 201, which penetrate the upper and lower surfaces of the partition 200 and connect the evaporation chamber 400 and the condensation chamber 500. The through holes 201 are used to allow steam to enter the condensation chamber 500 from the evaporation chamber 400, and at the same time allow the separated and condensed liquid working fluid to flow back to the evaporation chamber 400 through the through holes 201, thereby realizing the two-phase internal circulation of the working fluid.

[0051] The evaporation chamber 400 is provided with a working fluid inlet 401, and the condensation chamber 500 is provided with a working fluid outlet 501. The working fluid inlet 401 and the working fluid outlet 501 are arranged relatively far apart. The working fluid inlet 401 is used to supply liquid working fluid to the evaporation chamber 400, and the working fluid outlet 501 is used to discharge uncondensed steam from the condensation chamber 500.

[0052] A sintered metal powder layer 600 is fixed on one side of the heat exchange plate 100 inside the evaporation chamber 400. The sintered metal powder layer 600 is metallurgically bonded to the heat exchange plate 100 by sintering process. The sintered metal powder layer 600 is used to provide the vaporization nucleus for nucleation boiling and to achieve uniform distribution of the working fluid.

[0053] The numerous microporous structures in the sintered metal powder layer 600 form stable vaporization nuclei, enabling the liquid working fluid to undergo nucleation boiling at a relatively low superheat, significantly improving heat exchange efficiency. At the same time, the capillary action of the sintered metal powder layer 600 ensures that the liquid working fluid is evenly spread on the evaporation surface, preventing localized drying.

[0054] During operation, the liquid working fluid enters the evaporation chamber 400 through the working fluid inlet 401 and is uniformly distributed on the surface and in the internal pores of the sintered metal powder layer 600 under the action of capillary force and gravity. The heat generated by the external heating chip is transferred to the sintered metal powder layer 600 through the heat exchange plate 100. The liquid working fluid undergoes nucleation boiling at the vaporization core of the porous structure, absorbing a large amount of latent heat and turning into steam.

[0055] Steam flows upward through the through-hole 201 on the partition 200 and enters the condensation chamber 500, where it condenses into a liquid working fluid upon encountering cold and releasing heat. The condensed liquid working fluid flows back to the evaporation chamber 400 under gravity through the through-hole 201. The gaseous working fluid that has not been condensed is discharged through the working fluid outlet 501, condensed by an external radiator, and then pumped back to the working fluid inlet 401 by an external circulation pump, completing the two-phase external circulation.

[0056] This structure utilizes the latent heat of phase change for heat transfer, and its heat transfer coefficient can reach 10-100 times that of single-phase liquid cooling, effectively handling heat dissipation scenarios with heat flux densities exceeding 100W / cm².

[0057] like Figure 4 As shown, the heat exchange plate 100 includes a heat exchange base plate 101, which is made of a high thermal conductivity material, such as copper or aluminum alloy 6061. The thermal conductivity of copper is about 390 W / (m·K), and the thermal conductivity of aluminum alloy 6061 is about 167 W / (m·K). In this embodiment, copper is preferred.

[0058] The thickness of the heat exchange base plate 101 is 2-5mm, preferably 2mm in this embodiment. The lower surface of the heat exchange base plate 101 is a flat thermally conductive surface, which is used to bond and connect with the heat-generating chip through a thermally conductive interface material.

[0059] A number of uniformly distributed heat exchange fins 102 are provided on one side of the heat exchange base plate 101 located inside the evaporation chamber 400. The heat exchange fins 102 are arranged along the working fluid inlet 401 toward the working fluid outlet 501, that is, the length direction of the heat exchange fins 102 is consistent with the mainstream direction of the working fluid.

[0060] The heat exchange fins 102 are made of the same material as the heat exchange base plate 101. In this embodiment, the heat exchange fins 102 are integrally formed on the upper surface of the heat exchange base plate 101 by machining methods such as milling or tooth-shaving. The height of the heat exchange fins 102 is 5mm, the thickness is 1mm, and the spacing between adjacent heat exchange fins 102 is 3mm.

[0061] The sintered metal powder layer 600 is disposed on the side of the heat exchange fin 102, that is, the sintered metal powder layer 600 covers both sides of each heat exchange fin 102 and the upper surface of the heat exchange base plate 101 between the heat exchange fins 102, so that each heat exchange fin 102 becomes a reinforced boiling surface with a porous coating, which greatly increases the effective heat exchange area and vaporization core density in the evaporation chamber 400.

[0062] The heat exchange fins 102 expand the heat exchange area, and the sintered metal powder layer 600 provides nucleated boiling enhancement on the fin surface. The synergistic effect of the two increases the heat transfer coefficient by 50%-100% compared to ordinary smooth surfaces.

[0063] like Figure 4As shown, the heat exchange fins 102 have several equally spaced slots 103, which extend along the height of the heat exchange fins 102 and penetrate the top of the heat exchange fins 102. All the slots 103 on the heat exchange fins 102 are aligned along the direction from the working fluid inlet 401 to the working fluid outlet 501, forming a straight channel 104. The straight channel 104 penetrates the entire flow direction of the evaporation chamber 400, providing a low-resistance flow channel for the liquid working fluid and steam to pass through the evaporation chamber 400.

[0064] The straight groove 104 solves the flow blockage problem that may be caused by the uniform and dense distribution of heat exchange fins 102, allowing the working fluid to pass smoothly through the evaporation chamber 400 along the flow direction; at the same time, the equally spaced grooves 103 help to homogenize the pressure distribution in the evaporation chamber 400, promote the uniform distribution of the working fluid to each heat exchange fin 102 area, and avoid local overheating or insufficient liquid supply.

[0065] like Figure 3 and Figure 5 As shown, a reflux groove 202 is provided on the side of the partition 200 away from the working fluid inlet 401. The reflux groove 202 connects the evaporation chamber 400 and the condensation chamber 500. The reflux groove 202 provides an independent liquid phase reflux path for the condensed liquid working fluid, complementing the reflux function of the through hole 201.

[0066] Specifically, the through-hole 201 primarily facilitates upward steam flow with secondary liquid reflux, while the reflux channel 202 is specifically designed for the reflux of liquid working fluid from the condenser 500 to the evaporator 400, reducing liquid phase reflux resistance. The reflux channel 202 is located on the side furthest from the working fluid inlet 401, which helps form a complete circulation path. After the liquid working fluid enters the evaporator 400 through the working fluid inlet 401 and evaporates, the steam rises through the through-hole 201 to the condenser 500. After condensation, the liquid working fluid flows back through the reflux channel 202 to the far end of the evaporator 400, replenishing the working fluid towards the working fluid inlet 401 under capillary force and flow drive, forming a closed internal circulation.

[0067] The reflux tank 202 supplements the liquid phase reflux capacity of the through hole 201, prevents condensate from accumulating in the condensation chamber 500, ensures that the sintered metal powder layer 600 in the evaporation chamber 400 continuously receives a liquid working fluid supply, and avoids heat exchange deterioration caused by local drying.

[0068] like Figure 3 and Figure 5 As shown, a first recessed cavity 203 is formed on the lower surface of the partition plate 200, and the inner side of the first recessed cavity 203 is sealed with the upper surface of the heat exchange plate 100 to form an evaporation cavity 400. The depth of the first recessed cavity 203 is 5.5 mm, and it is machined on the lower surface of the partition plate 200 by mechanical milling.

[0069] The working fluid inlet 401 is located on the side of the partition 200, connecting to the first recessed cavity 203. A working fluid input pipe 204 is fixedly and sealed inside the working fluid inlet 401. The working fluid input pipe 204 is made of copper or stainless steel and is sealed to the partition 200 by brazing or welding. The working fluid input pipe 204 is used to connect to an external liquid supply system to introduce liquid working fluid into the evaporation chamber 400.

[0070] The first recessed cavity 203 precisely defines the spatial shape and volume of the evaporation cavity 400, which facilitates the control of the working fluid storage and evaporation space; the sealed connection of the working fluid input pipe 204 ensures the reliability of the liquid working fluid supply and the system's airtightness.

[0071] like Figure 6 As shown, the cover plate 300 is made of copper or aluminum alloy 6061, with a thickness of 10mm. A second recessed cavity 301 is formed on the lower surface of the cover plate 300, and the inner side of the second recessed cavity 301 is sealed with the upper surface of the partition plate 200 to form a condensation cavity 500. The second recessed cavity 301 has a depth of 5mm and is machined on the lower surface of the cover plate 300 by mechanical milling. A working fluid outlet 501 is located on the side of the cover plate 300, connecting to the second recessed cavity 301. A working fluid output pipe 302 is fixedly and sealed inside the working fluid outlet 501. The working fluid output pipe 302 is made of copper or stainless steel and is sealed to the cover plate 300 by brazing or welding. The working fluid output pipe 302 is used to connect to an external condensation system or circulation pipeline to discharge uncondensed gaseous working fluid and incompletely condensed two-phase mixed working fluid from the condensation cavity 500.

[0072] The second recessed cavity 301 precisely defines the spatial shape and volume of the condensation cavity 500, providing sufficient heat exchange space for steam condensation; the sealed connection of the working fluid output pipe 302 ensures the reliability of the working fluid discharge after condensation and the system's airtightness.

[0073] like Figure 7 As shown, the sintered metal powder layer 600 includes a first porous layer 601 and a second porous layer 602. Both the first porous layer 601 and the second porous layer 602 are fixed to the upper surface of the heat exchange base plate 101 and the side surface of the heat exchange fins 102 using a sintering process. The first porous layer 601 is close to the upper surface of the heat exchange plate 100, meaning it is directly sintered and bonded to the surface of the heat exchange plate 100; the second porous layer 602 is located on the side of the first porous layer 601 away from the heat exchange plate 100. The pore size of the first porous layer 601 is smaller than that of the second porous layer 602.

[0074] The first porous layer 601 is sintered from copper powder with a particle size of 20-50 μm, and the second porous layer 602 is sintered from copper powder with a particle size of 100-200 μm. The total thickness of the sintered metal powder layers 600 is 3 mm, of which the thickness of the first porous layer 601 is approximately 0.4 mm and the thickness of the second porous layer 602 is approximately 2.6 mm. The sintering process involves heating to a temperature below the melting point of the copper powder under a protective atmosphere such as nitrogen or argon, and holding at that temperature for 1-3 hours to form a metallurgical bond between the powder particles and between the powder and the heat exchange plate 100.

[0075] The small pores in the first porous layer 601 generate a strong capillary driving force, continuously adsorbing the liquid working fluid from the liquid region of the evaporation chamber 400 to the surface of the heat exchange plate 100. Simultaneously, the numerous micropores provide abundant vaporization nuclei, enabling nucleation boiling of the liquid working fluid at relatively low superheat. The large pores in the second porous layer 602 provide a low-resistance escape channel for steam. After steam is generated in the first porous layer 601, it rapidly diffuses into the main space of the evaporation chamber 400 through the large pores of the second porous layer 602, preventing steam from accumulating in the porous layer and forming a vapor film that would block the supply of liquid working fluid. This achieves functional separation between the inward supply of liquid phase and the outward discharge of vapor phase, effectively avoiding mutual interference between the reverse flow of vapor and liquid, and increasing the critical heat flux density to 300-500 W / cm².

[0076] An evaporation tank 603 is provided on the side of the sintered metal powder layer 600 away from the heat exchange plate 100, that is, on the outer side of the second porous layer 602. The length direction of the evaporation tank 603 is not parallel to the direction of the working fluid inlet 401 toward the working fluid outlet 501.

[0077] In this embodiment, the length direction of the evaporation tank 603 is perpendicular to the mainstream direction, and it is formed by molding before sintering. The evaporation tank 603 increases the contact area between the sintered metal powder layer 600 and the liquid working fluid, thereby increasing the evaporation heat exchange area. On the other hand, since the evaporation tank 603 is not parallel to the mainstream direction, the working fluid is guided by the evaporation tank 603 to generate lateral flow disturbance during the flow process, which enhances the uniformity of heat exchange in the evaporation chamber 400 and avoids the working fluid from flowing quickly through the evaporation area along the mainstream direction without sufficient heat exchange.

[0078] like Figure 2 and Figure 3 as well as Figure 8As shown, a metal mesh layer 700 is fixedly installed on the upper surface of the partition 200. The metal mesh layer 700 is formed by stacking and sintering several layers of metal wire mesh 701. In this embodiment, the metal mesh layer 700 is composed of 2-3 layers of metal wire mesh 701. The metal wire mesh 701 is made of copper, stainless steel, or nickel. In this embodiment, copper wire mesh is preferred, with a mesh count of 150 and a wire diameter of 0.1 mm. The metal wire mesh 701 is attached to the upper surface of the partition 200 through a sintering process under a protective atmosphere such as nitrogen or argon, so that the metal mesh layer 700 and the partition 200 form an integrated structure. Uniformly distributed steam passages 702 are formed on the metal mesh layer 700, and the equivalent pore size of the steam passages 702 is much smaller than the diameter of the through holes 201.

[0079] When steam rises from the evaporation chamber 400 through the through-hole 201 and passes through the partition 200, it may carry tiny droplets, i.e., incompletely separated liquid working fluid. As the steam continues to flow upward through the metal mesh layer 700, the fine pores of the metal mesh layer 700 intercept and filter the tiny droplets in the steam, achieving a second stage of gas-liquid separation. The intercepted droplets converge on the surface of the metal mesh layer 700 and, under the action of gravity, flow back to the evaporation chamber 400 through the through-hole 201, while the purified steam enters the condensation chamber 500 for condensation. The technical advantage of this structure is that the metal mesh layer 700 and the through holes 201 form a two-stage composite gas-liquid separation structure. The through holes 201 achieve the first stage of separation, blocking large droplets and guiding the steam upward. The metal mesh layer 700 achieves the second stage of separation, filtering out small droplets. The synergistic effect of the two stages of separation ensures that the steam entering the condensing chamber 500 has a high quality, effectively avoiding the problem of insufficient liquid supply to the evaporating chamber 400 caused by the liquid working fluid being carried into the condensing chamber 500 by the steam.

[0080] In this embodiment, the working fluid inlet 401 and the working fluid outlet 501 are arranged relatively far apart, that is, the working fluid inlet 401 is located on one side of the partition plate 200, and the working fluid outlet 501 is symmetrically located on the cover plate 300 on the side away from the working fluid inlet 401, so as to extend the flow path of the working fluid in the two-phase cold plate and improve the heat exchange efficiency.

[0081] The working fluid can be a fluoride working fluid, deionized water, R134a, R245fa, or ammonia, etc. In this embodiment, the preferred fluoride working fluid is FC-72, which has a boiling point of 56°C and a working pressure of 0.1 MPa. The overall dimensions of the two-phase cold plate can be adjusted according to the heat dissipation requirements.

[0082] Example 2 Please refer to the above as well. Figure 9 and Figure 10 In one embodiment of this application, a method for preparing a two-phase cold plate using a sintered metal powder layer includes the following steps: Step S1, Part pretreatment: Pretreatment of the upper surface of the heat exchange plate 100.

[0083] Specifically, first use acetone or alcohol to ultrasonically clean the surface of heat exchange plate 100 for 10-30 minutes to remove surface oil and organic contaminants; then soak the surface of heat exchange plate 100 in 5%-10% dilute hydrochloric acid or 3%-5% dilute sulfuric acid for 5-15 minutes to remove the surface oxide layer; finally rinse with deionized water and dry.

[0084] The purpose of pretreatment is to ensure that the surface of the heat exchange plate 100 is clean, so as to ensure that a good metallurgical bond can be formed between the subsequent sintered metal powder layer 600 and the heat exchange plate 100, thereby improving the bonding strength and thermal conductivity.

[0085] Step S2, preparing a sintered metal powder layer: Install a tooling mold 800 in the corresponding area of ​​the evaporation chamber on the upper surface of the heat exchange plate 100, then evenly spread the metal powder in the tooling mold 800, and perform sintering treatment under a protective atmosphere to form a metallurgical bond between the metal powder particles and between the metal powder and the heat exchange plate, thus forming a sintered metal powder layer.

[0086] Specifically, firstly, a frame-shaped fixture 801 is placed on the upper surface of the heat exchange plate 100, and then a first layer of metal powder is evenly spread inside the frame-shaped fixture 801. The first layer of metal powder is copper powder with a particle size of 20-50μm. Then, a strip-shaped fixture 802 is installed on the frame-shaped fixture 801. Then, a second layer of metal powder is evenly spread in the remaining space between the frame-shaped fixture 801, the strip-shaped fixture 802, and the heat exchange fins 102. The second layer of metal powder is copper powder with a particle size of 100-200μm.

[0087] The frame-shaped fixture 801 encloses an area corresponding to the evaporation chamber 400, defining the area for the metal powder layer and the outline of the sintered metal powder layer 600. The strip-shaped fixture 802, located inside the frame-shaped fixture 801, defines the area for the metal powder layer and the internal shape of the sintered metal powder layer 600. Both the frame-shaped fixture 801 and the strip-shaped fixture 802 are made of graphite or high-temperature resistant stainless steel. The first layer of metal powder corresponds to the first porous layer 601, the second layer corresponds to the second porous layer 602, and the internal shape of the sintered metal powder layer 600 corresponds to the evaporation tank 603.

[0088] After the first and second layers of metal powder are laid, the heat exchange plate 100 with the metal powder is placed in a sintering furnace and sintered under a protective atmosphere of nitrogen or argon with a purity of ≥99.99%. The sintering temperature is 850℃-980℃, the holding time is 1-3 hours, and the heating rate is 5-10℃ / min.

[0089] During the sintering process, metal powder particles form metallurgical bonds through solid-state diffusion between themselves and between the metal powder and the surface of the heat exchange plate 100. After sintering, the furnace is cooled to room temperature, and the strip tooling 802 and the frame tooling 801 are removed to form a sintered metal powder layer 600.

[0090] A porous layer with numerous micropore vaporization nuclei and capillary forces is formed on the surface of the heat exchange plate 100 through a sintering process, providing a structural basis for subsequent nucleation boiling heat exchange.

[0091] Step S3, Assembly and Sealing Connection: Assemble and seal the partition plate 200 and cover plate 300 sequentially onto the heat exchange plate 100.

[0092] Specifically, firstly, a partition plate 200 with several through holes 201 is placed above a heat exchange plate 100 with a sintered metal powder layer 600. The lower surface of the partition plate 200 with a first recessed cavity 203 faces the heat exchange plate 100, and the first recessed cavity 203 and the upper surface of the heat exchange plate 100 enclose each other to form an evaporation chamber 400. Then, a cover plate 300 is placed above the partition plate 200. The lower surface of the cover plate 300 with a second recessed cavity 301 faces the partition plate 200, and the second recessed cavity 301 and the upper surface of the partition plate 200 enclose each other to form a condensation chamber 500.

[0093] Before assembly, if a metal mesh layer 700 has been attached to the partition 200 by a sintering process, the metal mesh layer 700 is located on the surface of the partition 200 facing the second recessed cavity 301.

[0094] After assembly, the heat exchange plate 100, partition plate 200, and cover plate 300 are placed in a vacuum brazing furnace or diffusion welding equipment, and the heat exchange plate 100, partition plate 200, and cover plate 300 are sealed and connected as a whole using vacuum brazing or diffusion welding. At the same time, the working fluid inlet pipe 204 and the working fluid outlet pipe 302 are respectively sealed and installed at the working fluid inlet 401 and the working fluid outlet 501 through brazing or welding processes.

[0095] The brazing temperature for vacuum brazing is 620℃-780℃, and the vacuum degree is ≤10. - ³Pa, holding time 5-15 minutes; diffusion welding temperature 800℃-900℃, pressure 5-15MPa, holding time 30-60 minutes; vacuum brazing or diffusion welding process can ensure reliable sealing connection between the three-layer plates, with high joint strength and good airtightness, and can withstand thermal cycling and pressure fluctuations during long-term operation of two-phase cold plates.

[0096] Step S4, airtightness test and working fluid injection: Perform airtightness test and working fluid injection on the two-phase cold plates after sealing connection.

[0097] Specifically, the airtightness of the two-phase cold plate is first tested using helium mass spectrometry leak detection. The test pressure is 1.5-2 times the design working pressure, and the pressure holding time is no less than 30 minutes. The leakage rate should be less than 1×10⁻⁶. -9 Pa·m³ / s.

[0098] After the airtightness test is passed, the two-phase cold plate is connected to the vacuum injection system. First, the evaporation chamber 400 and the condensation chamber 500 are evacuated to below 10 Pa to remove air and non-condensable gases from the chambers. Then, the working fluid is injected through the working fluid input pipe 204 under vacuum conditions to complete the preparation of the two-phase cold plate.

[0099] After filling, you can choose to seal the working fluid inlet 401 and the working fluid outlet 501 before storing it, or you can connect the working fluid inlet 401 and the working fluid outlet 501 to an external circulating heat dissipation system for use.

[0100] This application uses vacuum injection to remove non-condensable gases such as air from the cavity, preventing the accumulation of non-condensable gases in the condensation cavity 500 and reducing the condensation heat exchange efficiency, thus ensuring the stable operation of the two-phase cycle.

[0101] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A two-phase cold plate employing a sintered metal powder layer, characterized in that: The device includes a heat exchange plate, a partition plate sealed to the heat exchange plate, and a cover plate sealed to the partition plate. An evaporation chamber is formed between the heat exchange plate and the partition plate, and a condensation chamber is formed between the partition plate and the cover plate. The partition plate has several through holes connecting the evaporation chamber and the condensation chamber. The evaporation chamber has a working fluid inlet, and the condensation chamber has a working fluid outlet, which are arranged relatively far apart. A sintered metal powder layer is fixed on one side of the heat exchange plate located inside the evaporation chamber.

2. The two-phase cold plate employing a sintered metal powder layer according to claim 1, characterized in that, The heat exchange plate includes a heat exchange base plate, on which a plurality of uniformly distributed heat exchange fins are arranged on one side inside the evaporation chamber. The heat exchange fins are arranged along the working fluid inlet toward the working fluid outlet, and the sintered metal powder layer is disposed on the side of the heat exchange fins.

3. The two-phase cold plate employing a sintered metal powder layer according to claim 2, characterized in that, The heat exchange fins are provided with a number of equally spaced slots, and all the slots on the heat exchange fins form a straight channel along the working fluid inlet toward the working fluid outlet.

4. The two-phase cold plate employing a sintered metal powder layer according to claim 1, characterized in that, A reflux groove connecting the evaporation chamber and the condensation chamber is provided on the side of the partition away from the working fluid inlet.

5. The two-phase cold plate employing a sintered metal powder layer according to claim 1, characterized in that, The lower surface of the partition plate has a first recessed cavity. The inner side of the first recessed cavity is sealed with the upper surface of the heat exchange plate to form the evaporation cavity. The working fluid inlet is located on the side of the partition plate, communicating with the first recessed cavity. The working fluid inlet is fixedly and sealed with a working fluid input pipe.

6. The two-phase cold plate employing a sintered metal powder layer according to claim 1, characterized in that, The lower surface of the cover plate has a second recessed cavity, and the inner side of the second recessed cavity is sealed with the upper surface of the partition plate to form the condensation cavity. The working fluid outlet is located on the side of the cover plate, which is connected to the second recessed cavity, and a working fluid output pipe is fixedly and sealed inside the working fluid outlet.

7. The two-phase cold plate employing a sintered metal powder layer according to claim 1, characterized in that, The sintered metal powder layer includes a first porous layer and a second porous layer. The first porous layer and the second porous layer are fixed on the upper surface of the heat exchange plate by a sintering process. The first porous layer is close to the upper surface of the heat exchange plate, and the pores of the first porous layer are smaller than the pores of the second porous layer.

8. The two-phase cold plate employing a sintered metal powder layer according to claim 1, characterized in that, An evaporation tank is provided on the side of the sintered metal powder layer away from the heat exchange plate, and the length direction of the evaporation tank intersects the direction of the working fluid inlet toward the working fluid outlet.

9. The two-phase cold plate employing a sintered metal powder layer according to claim 1, characterized in that, A metal mesh layer is fixedly installed on the upper surface of the partition. The metal mesh layer is formed by stacking and sintering several layers of metal wire mesh, and the metal mesh layer forms a uniformly dense steam passage.

10. A method for preparing a two-phase cold plate employing a sintered metal powder layer as described in any one of claims 1 to 9, characterized in that, Includes the following steps: Step S1, Part pretreatment: Pretreatment of the upper surface of the heat exchange plate; Step S2, preparing a sintered metal powder layer: install a tooling mold in the corresponding area of ​​the evaporation chamber on the upper surface of the heat exchange plate, then evenly spread the metal powder in the tooling mold, and perform sintering treatment under a protective atmosphere to form a metallurgical bond between the metal powder particles and between the metal powder and the heat exchange plate, thus forming a sintered metal powder layer. Step S3, Assembly and Sealing Connection: Assemble and seal the partition and cover plate sequentially onto the heat exchange plate; Step S4, airtightness test and working fluid injection: Perform airtightness test and working fluid injection on the two-phase cold plates after sealing connection.

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