Radiator

Abstract

The invention provides a radiator which comprises a first cavity structure, a closed two-phase heat exchange cavity is formed in the first cavity structure, and a gas-liquid two-phase working medium is packaged in the two-phase heat exchange cavity and used for heat diffusion through evaporation and condensation circulation after heat is absorbed; the second cavity structure is adjacent to the first cavity structure and forms an independent liquid cooling circulation cavity, and the liquid cooling circulation cavity is provided with a liquid inlet port and a liquid outlet port and is used for enabling a single-phase liquid cooling medium to flow in the liquid cooling circulation cavity so as to take away heat transferred by the first cavity structure; wherein a heat contact surface is formed on one side of the first cavity structure and used for being in contact with a heat source and transmitting heat generated by the heat source to the two-phase heat exchange cavity, and an interface heat conduction part is formed on the other opposite side of the first cavity structure and located between the two-phase heat exchange cavity and the liquid cooling circulation cavity. And the single-phase liquid cooling medium is used for transferring heat which is subjected to phase change circulation diffusion in the two-phase heat exchange cavity to the liquid cooling circulation cavity.

Description

Technical Field

[0001] This application relates to the field of chip heat dissipation technology, and more specifically, to a chip heat sink with dual working fluid circulation. Background Technology

[0002] To cope with the increasing demand for chip heat dissipation, such as the power consumption of the new generation of AI chips reaching over 700W and the heat flux density on the chip surface reaching as high as 86W / cm², traditional liquid cooling radiators are gradually becoming unable to meet the heat dissipation requirements in high heat flux density scenarios, and are therefore being gradually replaced by microchannel liquid cooling radiators.

[0003] For example, Chinese patent application CN119136488A, entitled "Microchannel Liquid Cooling Radiator," discloses a microchannel liquid cooling structure. This application provides a microchannel liquid cooling radiator to achieve high temperature uniformity in heat dissipation. Figure 1 The diagram shows a first microchannel region and a second microchannel region separated from each other, connected by a microchannel outlet of the first microchannel region and a microchannel inlet of the second microchannel region, allowing liquid working fluid flowing out of the first microchannel region to enter the second microchannel region via the connecting cavity. Generally, microchannel heat sinks significantly increase the heat dissipation area above the chip, while simultaneously increasing the flow rate of the medium fluid within the channels through a compression effect, thus providing higher heat dissipation efficiency than traditional liquid cooling heat sinks.

[0004] However, existing microchannel liquid-cooled heat sinks still have the following shortcomings: 1) The medium in the microchannel is still mainly laminar, and the convective heat transfer coefficient between the heat dissipation interface (i.e., the surface of the microchannel fins) and the medium fluid has not been improved; 2) The flow cross-section of the fluid shrinks sharply when it enters the microchannel, which increases the fluid velocity in the channel but also greatly increases the flow resistance of the structure; 3) The lateral heat diffusion capability of the microchannel is almost not improved compared with ordinary fins; 4) Due to process limitations, the processing / manufacturing cost of microchannels increases sharply as the channel width decreases. For example, when the channel width (gap) reaches less than 100 micrometers, its cost is more than 5 times that of traditional finned heat sinks.

[0005] To address the aforementioned issues, existing technologies lack effective solutions that can simultaneously achieve high heat transfer efficiency, low flow resistance, good lateral heat diffusion capability, and controllable costs. Summary of the Invention

[0006] This application provides a radiator to solve the problem of low heat exchange efficiency in existing radiators.

[0007] According to one aspect of the embodiments of this application, a heat sink is provided, comprising: a first cavity structure having a sealed two-phase heat exchange cavity inside, wherein a gas-liquid two-phase working fluid is encapsulated within the two-phase heat exchange cavity for heat diffusion through evaporation and condensation cycles after absorbing heat; and a second cavity structure adjacent to the first cavity structure and forming an independent liquid-cooled flow cavity, wherein the liquid-cooled flow cavity has an inlet port and an outlet port for allowing a single-phase liquid cooling medium to flow within the liquid-cooled flow cavity to remove the heat transferred by the first cavity structure; wherein, a thermal contact surface is formed on one side of the first cavity structure for contacting a heat source and transferring the heat generated by the heat source to the two-phase heat exchange cavity, and an interface thermally conductive portion is formed on the opposite side, wherein the interface thermally conductive portion is located between the two-phase heat exchange cavity and the liquid-cooled flow cavity for transferring the heat diffused by the phase change cycle in the two-phase heat exchange cavity to the single-phase liquid cooling medium in the liquid-cooled flow cavity. The interface thermally conductive portion refers to a solid isolation structure located between the two-phase heat exchange cavity and the liquid-cooled flow cavity for conducting heat. Specifically, the interface thermally conductive portion is a cover plate. The above structure allows for both two-phase internal circulation of the working fluid and single-phase liquid-cooled external circulation, thereby achieving dual-circulation heat exchange and improving overall heat dissipation efficiency.

[0008] In some embodiments, the heat sink further includes: a substrate, in which a first groove and a second groove are formed sequentially connected along the same opening direction, the opening cross-sectional area of ​​the first groove being smaller than that of the second groove; wherein the first cavity structure is composed of the first groove and a cover plate closing the opening of the first groove to form the two-phase heat exchange cavity therein, wherein the cover plate is the interface heat-conducting part; the second cavity structure is composed of the cover plate, the second groove, and a top plate closing the opening of the second groove to form the liquid-cooled flow cavity therein. With the above structure, efficient heat transfer can be achieved.

[0009] In some embodiments, the cross-sectional area of ​​the two-phase heat exchange cavity gradually increases from the evaporation surface to the condensation surface along the normal direction, and a storage area for accommodating the liquid two-phase working fluid is formed near the evaporation surface. The remaining space constitutes a reflux zone, which is provided with a reflux wall to guide the condensed liquid working fluid back to the storage zone. The evaporation surface is the bottom surface of the first groove, and the condensation surface is the side surface of the cover plate facing the first groove. This structure promotes working fluid reflux and improves the stability of the phase change cycle.

[0010] In some embodiments, evaporation fins are provided in the liquid storage area, wherein the evaporation fins extend from the evaporation surface toward the condensation surface; the evaporation fins extend parallel to the short side of the substrate and are spaced apart along a direction parallel to the long side of the substrate to guide the vapor generated by evaporation to expand in a predetermined direction to the condensation surface within the two-phase heat exchange cavity. With this structure, heat can be expanded horizontally through the circulation of the two-phase working fluid in the two-phase heat exchange cavity, thereby reducing the heat flux density at the liquid cooling end. The evaporation fins employ a microgroove structure, i.e., a dense array of grooves is provided on the metal surface. Under the capillary pressure gradient formed by the microgrooves, the liquid working fluid is automatically drawn in and flows along the channels, eliminating the need for external power such as pumps or fans. The two-phase working fluid forms a composite process of thin liquid film evaporation (meniscus region) and thick liquid film nucleation boiling in the microgroove heating zone. A large amount of heat is removed using the latent heat of vaporization, and the vapor releases heat and flows back at the condensation surface, forming a passive circulation.

[0011] In some embodiments, a plurality of support columns are further provided in the first groove, and the plurality of support columns are welded and fixedly connected to the cover plate, and the evaporation fins are welded and fixedly connected to the cover plate. This structure enhances structural strength and improves sealing reliability.

[0012] In some embodiments, a plurality of condensing fins are provided on the condensing surface of the cover plate. The condensing fins extend in the same direction as the gas guide groove and together with the gas guide groove, form a channel structure for guiding the flow of medium vapor and achieving cooling and condensation. This embodiment increases the area of ​​the condensing surface by using condensing fins, thereby accelerating the vapor condensation rate and matching the evaporation rate and condensation rate of the two-phase working fluid.

[0013] In some embodiments, turbulent fins are provided on the side of the cover plate away from the first groove. The turbulent fins are welded and fixed to the cover plate to define a first flow channel for the single-phase liquid in the liquid-cooled flow cavity. In this embodiment, the turbulent fins can increase the convective heat transfer capacity of the deheating surface and the liquid-cooled working fluid.

[0014] In some embodiments, the cover plate is integrally formed from a thin metal sheet by stamping, and includes a plurality of crests and troughs spaced apart along a predetermined direction. The crests and troughs form a hollow cavity channel facing the evaporation surface. The hollow cavity channel extends in the same direction as the gas guide channel and, together with the gas guide channel, forms a channel structure for guiding the flow of medium vapor and achieving cooling and condensation. With this structure, the area of ​​the heat dissipation surface is smaller than that of the heat sink with turbulent fins (including the fin area), and it no longer has turbulent fins. However, the areas of the condensation surface and the heat dissipation surface are more matched, thereby achieving the technical objective of diffusing the heat generated by the chip through the two-phase working fluid phase change cycle in the two-phase heat exchange cavity to a larger heat dissipation surface.

[0015] In some embodiments, the side of the cover plate away from the evaporation surface abuts against the top plate, defining a first flow channel for the single-phase liquid in the liquid-cooled flow chamber. This structure allows for the formation of a first flow channel, thereby increasing the heat dissipation area.

[0016] In some embodiments, a second flow channel is further formed within the liquid-cooled flow cavity. The second flow channel is formed by the second groove and the top plate, and is used to define the path of the single-phase liquid to the outlet port after flowing through the first flow channel. This structure optimizes the flow path and balances the fluid distribution.

[0017] In some embodiments, a plurality of flow distribution devices are provided within the second flow channel. These multiple flow distribution devices include at least one of the following: a flow-guiding groove, a partition with separating ribs, a partition without separating ribs, and a flow-limiting groove. The flow channel cross-section of the flow-guiding groove is larger than the standard flow channel cross-section at the flow channel reference plane, and the flow channel cross-section at the flow-limiting groove is smaller than the standard flow channel cross-section. This structure allows for adjustment of flow distribution and improved heat exchange uniformity.

[0018] In some embodiments, the width of the gas guide groove is greater than the spacing between adjacent evaporator fins. This structure reduces vapor flow resistance and promotes directional expansion.

[0019] In some embodiments, a capillary surface layer is provided on the outer surfaces of the evaporation surface, the condensation surface, and the evaporation fins, support column, and condensation fins. This structure enhances capillary reflux and improves phase change efficiency. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0021] Figure 1 It is a structural diagram of a chip heat sink based on existing technology;

[0022] Figure 2 This is an exploded view of the heat sink disclosed in the embodiments of this application;

[0023] Figure 3 This is a cross-sectional view of the heat sink disclosed in the embodiments of this application;

[0024] Figure 4 This is an exploded view of the radiator after partial cross-section, as disclosed in the embodiments of this application;

[0025] Figure 5 This is a schematic diagram of the evaporation-condensation process of the evaporation fins disclosed in the embodiments of this application;

[0026] Figure 6 This is an internal structural diagram of the liquid cooling flow cavity of the radiator disclosed in the embodiments of this application;

[0027] Figure 7 This is an internal structural diagram of a heat sink with a flow distribution device disclosed in an embodiment of this application;

[0028] Figure 8 This is an internal structural diagram of a heat sink using a hollow finned cover plate disclosed in an embodiment of this application;

[0029] Figure 9 This is a cross-sectional view of a heat sink with a hollow finned cover plate disclosed in an embodiment of this application;

[0030] The above figures include the following reference numerals:

[0031] 10. Substrate; 20. Cover plate; 30. Turbulent fins; 40. Top plate; 110. First groove; 111. Evaporation fins; 111a. Air guide groove; 112. Support column; 115. First thermal contact surface; 116. Evaporation surface; 119. Return wall; 120. Second groove; 1200. Flow channel reference surface; 1201. Flow guide groove; 1202. Partition with partition ribs; 1203. Partition without partition ribs; 1204. Flow limiting groove; 125. Second thermal contact surface; 135. Third thermal contact surface; 201. Condensation surface; 202. Deheating surface; 203. Condensation fins; 401. Liquid inlet; 402. Liquid outlet; 403. Transition flow channel; 404. Fluid distribution channel; 50. Two-phase heat exchange chamber; 60. Liquid-cooled flow chamber. Detailed Implementation

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0034] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0035] This invention provides a dual-fluid cycle chip heat sink that combines phase change fluid cycle and traditional liquid cooling cycle, providing better heat dissipation efficiency to meet the increasing heat dissipation requirements of chip heat flux density.

[0036] like Figures 2 to 9 As shown, the heat sink provided in this application includes a base 10, a cover plate 20, and a top plate 40. The base 10 has a first groove 110 and a second groove 120. The cover plate 20 closes the first groove to form a sealed two-phase heat exchange cavity 50. The top plate has a liquid inlet 401 and a liquid outlet 402, and closes the second groove to form a liquid-cooled flow cavity 60 for fluid medium circulation. A gas-liquid two-phase working fluid is provided in the two-phase heat exchange cavity, and a single-phase liquid medium flows in the liquid-cooled flow cavity. The outer bottom surface of the two-phase heat exchange cavity forms a first thermal contact surface 115 and contacts a first heat source, such as the core chip on a PCB board with the highest heat dissipation. The cover plate 20 is located between the two-phase heat exchange cavity and the liquid-cooled flow cavity, forming a heat transfer path between them.

[0037] In some embodiments, depending on the external cooling conditions (e.g., a chiller or cooling tower), phase change working fluids (coolants) with different boiling points are preferred to achieve a balance between heat dissipation efficiency and energy consumption. Specifically, since the junction temperature of a chip is typically in the range of 80~105°C, when an external chiller with a refrigeration cycle is connected, the cooling water temperature is easily controlled at around 20°C. In this case, a phase change working fluid with a boiling point between 25°C and 40°C is preferred to achieve a higher phase change heat transfer efficiency. When an external cooling tower with natural cooling is connected, the cooling water temperature is slightly higher than the ambient temperature, especially in summer when it can reach 40°C~50°C. In this case, a phase change working fluid with a boiling point between 50~65°C is preferred. Since no additional external refrigeration cycle is required, external energy consumption can be greatly reduced.

[0038] like Figure 3 As shown, the two-phase heat exchange cavity has a gradually increasing cross-sectional area along the normal direction from the evaporation surface 116 to the condensation surface 201. At the bottom of the substrate 10, a second thermal contact surface 125, a third thermal contact surface 135, etc., can also be provided as needed to achieve heat dissipation for multiple non-core chips.

[0039] The gas-liquid two-phase working fluid injected into the two-phase heat exchange chamber transfers heat from the smaller evaporation surface to the larger condensation surface through an evaporation-condensation cycle, thereby reducing the heat flux density of the deheating surface 202. Figure 3 The arrows indicate the approximate direction of vapor flow; the medium vapor expands horizontally after reaching the condensation surface 201. In this embodiment, the evaporation surface refers to the surface within the two-phase heat exchange cavity that directly corresponds to the heat source and is where the liquid working fluid undergoes heating and evaporation. Specifically, it is the bottom surface of the first groove, i.e., the inner wall surface opposite the heat contact surface. The condensation surface refers to the inner wall surface within the two-phase heat exchange cavity that is opposite the evaporation surface and is used to cool the vapor and cause phase change condensation. Specifically, it is the surface of the cover plate facing the first groove. The deheating surface refers to the solid surface used to transfer heat to the external single-phase liquid cooling medium, which is in direct contact with the liquid-cooled flow cavity. Specifically, it is the surface of the cover plate away from the first groove and the turbulence fins disposed on this surface.

[0040] In some embodiments, such as Figure 4As shown, evaporation fins 111 are provided in the two-phase heat exchange cavity to facilitate rapid evaporation of the gas-liquid two-phase working fluid. The evaporation fins 111 extend parallel to the short side of the base 10 and have several guide grooves 111a formed parallel to the long side of the base 10 to guide the vapor generated by evaporation to expand in a predetermined direction to the condensation surface within the two-phase heat exchange cavity. Through this structure, the heat can be expanded horizontally through the circulation of the two-phase working fluid in the two-phase heat exchange cavity, thereby reducing the heat flux density at the liquid cooling end. The evaporation fins employ a microgroove structure, i.e., a dense array of grooves is provided on the metal surface. Under the capillary pressure gradient formed by the microgrooves, the liquid working fluid is automatically drawn in and flows along the channels, eliminating the need for external power sources such as pumps and fans. Figure 5 As shown, the two-phase working fluid undergoes a combined process of thin liquid film evaporation (meniscus region) and thick liquid film nucleus boiling in the micro-groove heating zone. A large amount of heat is removed using the latent heat of vaporization, and the steam releases heat and refluxes at the condensation surface, forming a passive cycle.

[0041] like Figure 4 As shown, several support columns 112 are also provided in the first groove of the substrate 10. The evaporation fins 111 and the support columns 112 are all welded and fixedly connected to the cover plate 20. Since the pressure in the two-phase heat exchange cavity increases when the gas-liquid working fluid is vaporized, the fixed connection between the substrate and the cover plate helps to maintain the sealing of the two-phase heat exchange cavity and the stability of the structure. At the same time, the evaporation fins 111 also provide an additional solid heat transfer channel from the evaporation surface 116 to the condensation surface 201.

[0042] As mentioned earlier, the cross-sectional area of ​​the two-phase heat exchange cavity gradually increases from the evaporation surface 116 to the condensation surface 201 along the normal direction. The internal space of the two-phase heat exchange cavity can be divided into two regions according to function. The part near the evaporation surface 116 with a basically constant cross-sectional area is a liquid storage tank for containing the liquid two-phase working fluid. The space formed by the remaining volume in the two-phase heat exchange cavity is a reflux chamber, which is equipped with a reflux wall 119 to assist the reflux of the two-phase working fluid after condensation. Figure 3 The dashed line in the diagram roughly shows the "interface" between the storage tank and the reflux chamber.

[0043] like Figure 4 As shown, the cover plate 20 is provided with a plurality of condensing fins 203, the extension direction of which is consistent with the extension direction of the air guide groove 111a, and together they form a cooling / condensation channel for the medium vapor.

[0044] In some embodiments, the width of the gas guide groove 111a can be greater than the spacing between the evaporation fins to reduce the flow resistance of the evaporation fins 111 along the long side of the substrate 10, thereby guiding the medium vapor mainly along... Figure 3 The hollow arrow in the image indicates the direction of flow.

[0045] On the inner surface of the two-phase heat exchange cavity, namely the evaporation surface 116 and the condensation surface 201, as well as the outer surface of the evaporation fins 111, the support column 112 and the condensation fins 203, a capillary surface layer (not shown in the figure) is provided. Its function is to increase the heating area of ​​the medium, promote the shedding of bubbles during evaporation and achieve rapid reflux through adsorption during the condensation of the medium.

[0046] Turbulent fins 30 are disposed above the cover plate 20, and the turbulent fins 30 are welded and fixed to the cover plate 20 to reduce interfacial thermal resistance. Their function is to increase the actual heat dissipation area of ​​the heat dissipation surface 202 and enhance the convective heat transfer capacity between the heat dissipation surface 202 and the single-phase liquid medium in the liquid-cooled flow cavity. According to experimental results of some embodiments, the solid-liquid convective heat transfer capacity is improved by approximately 30% after adopting the turbulent fins.

[0047] The top plate 40 is typically made of a non-metallic material with a low thermal transfer coefficient. This characteristic helps control the surface temperature of the radiator and promotes heat exchange between the heat source and the single-phase liquid medium flowing within the liquid cooling circulation chamber, thereby reducing the adverse effects on the ambient temperature of the space surrounding the radiator. This is especially important when multiple radiators are located in the same chassis or cabinet.

[0048] The top plate 40 is provided with a liquid inlet 401 and a liquid outlet 402. In addition, the top plate 40 and the base 10 are sealed together to form a liquid-cooled flow chamber for media circulation. Due to the different materials, the sealing connection here typically uses a sealing ring and fasteners. The liquid inlet 401 is connected to a fluid distribution channel 404 via a transition channel 403, and the fluid distribution channel 404 has a cross-section that gradually narrows along the media flow direction.

[0049] The fluid medium flows through the turbulent fins 30 and follows a predetermined flow path, defined by the second groove 120 and the top plate 40. This flow path includes a first flow path and a second flow path. As described above, turbulent fins are provided on the side of the cover plate away from the first groove. One side of the turbulent fins is welded and fixed to the cover plate, and the other side abuts against the top plate. The top plate, the cover plate, and the turbulent fins define the first flow path (corresponding to) of the single-phase liquid in the liquid-cooled flow chamber. Figure 6 The region where the turbulent fin 30 is located). The second flow channel (roughly corresponding to...) Figure 7 The area (excluding the dashed area of ​​the turbulent fins) is formed by the second groove and the top plate, which together define the path of the single-phase liquid to the outlet port after flowing through the first flow channel.

[0050] Figure 6 The shortest flow path ① and the longest flow path ② are schematically shown. To ensure a relatively uniform flow velocity in each flow path, this embodiment of the application also includes multiple flow distribution devices, such as... Figure 7The flow channel 1201, the partition 1202 with partition ribs, the partition 1203, and the flow limiting channel 1204 shown are provided. The flow channel cross-section at the flow channel 1201 is larger than the standard flow channel cross-section at the flow channel reference plane 1200, and the flow channel cross-section at the flow limiting channel 1204 is smaller than the standard flow channel cross-section.

[0051] This application also provides another type of heat sink structure, such as... Figure 8 and Figure 9 As shown, the difference between this heat sink and the previous embodiment is that the cover plate 20 in this embodiment has a hollow finned structure, and the two-phase heat exchange cavity has a larger condensation surface 201 area than the previous embodiment. Meanwhile, the area of ​​the deheating surface 202 is smaller than the deheating surface area (including turbulent fins) in the previous embodiment, and it no longer has turbulent fins. However, the areas of the condensation surface and the deheating surface are more matched, and the technical objective of diffusing the heat generated by the chip through the two-phase working fluid circulation in the two-phase heat exchange cavity to a larger deheating surface can still be achieved. This embodiment can further increase the condensation surface area, and the better match between the condensation surface area and the deheating surface area can reduce the heat flux density at the liquid cooling end.

[0052] Specifically, in this embodiment, the cover plate adopts a hollow finned plate structure formed by stamping a thin metal sheet, with multiple hollow cavities formed inside the hollow fins. The hollow cavities facing the evaporation surface are connected to the two-phase heat exchange chamber, allowing vapor to enter the hollow cavities for condensation during the two-phase circulation process. Therefore, condensation occurs not only on the surface of the cover plate facing the two-phase heat exchange chamber but also on the inner wall surface of the hollow fins, thus expanding the condensation structure from a two-dimensional planar structure to a three-dimensional volumetric condensation structure.

[0053] Similarly, in this embodiment, a first flow channel and a second flow channel are also formed in the liquid-cooled flow cavity. The side of the cover plate away from the evaporation surface abuts against the top plate, forming a first flow channel that defines the single-phase liquid in the liquid-cooled flow cavity. The second flow channel is formed by the second groove and the top plate together, and is used to define the path of the single-phase liquid to the outlet port after flowing through the first flow channel.

[0054] Multiple flow distribution devices are provided in the second flow channel. The multiple flow distribution devices include at least one of the following: a flow guide channel, a partition with partition ribs, a partition without partition ribs, and a flow limiting channel. The flow channel cross-section of the flow guide channel is larger than the standard flow channel cross-section at the flow channel reference plane, and the flow channel cross-section at the flow limiting channel is smaller than the standard flow channel cross-section.

[0055] In some preferred embodiments, the hollow fins are provided with flow guiding gaps or throttling channels to reduce the vapor velocity and prolong the residence time of vapor in the fin cavity, thereby enhancing the condensation effect. In other embodiments, the hollow fins have at least one necked section with a reduced cross-sectional area along their extension direction, or are provided with a transverse baffle structure, wherein the transverse baffle and the cavity wall form a flow guiding gap to constitute a baffle-type throttling channel.

[0056] In some embodiments, the internal cavity of the hollow fin includes at least one throttling unit, which includes a converging section, a throat section, and a expanding section connected in sequence, wherein the cross-sectional area of ​​the throat section is smaller than the cross-sectional areas of the converging and expanding sections. A liquid collecting tank is provided at the lower part of the expanding section, and the liquid collecting tank is connected to the two-phase heat exchange cavity through a reflux hole. Further, multiple throttling units are spaced apart along the extension direction of the hollow fin to form a multi-stage throttling condensation structure, so that the vapor is gradually reduced in speed and condensed in sections inside the cavity. In some embodiments, the cavity also includes a main vapor channel and multiple lateral bypass condensation chambers, and the bypass condensation chambers are connected to the main channel through flow guide gaps.

[0057] This embodiment alters the steam flow path upon entering the fin cavity by incorporating guide gaps or throttling channels within the hollow fins, creating localized areas of reduced velocity. This prolongs the steam's residence time within the fin cavity, enhancing the heat exchange contact between the steam and the fin's inner wall and improving condensation efficiency. Furthermore, by incorporating a reduced-cross-sectional area necking section or transverse baffle structure along the cavity's extension direction, a baffle-type throttling channel is formed within the cavity. This creates multiple low-velocity condensation zones within the cavity, promoting staged steam condensation and preventing high-speed steam from passing through the cavity without sufficient heat exchange.

[0058] The specific working process of the radiator will be described below.

[0059] When the chip starts operating and generates heat, the heat is first conducted to the substrate via the first thermal contact surface, and further transferred to the bottom surface of the first groove, i.e., the evaporation surface. The liquid two-phase working fluid in the storage area near the evaporation surface absorbs heat from the evaporation surface and undergoes a phase change and vaporization, thus forming vapor. Because the cross-sectional area of ​​the two-phase heat exchange cavity gradually increases along the normal direction from the evaporation surface to the condensation surface, the vapor expands and flows within the two-phase heat exchange cavity under pressure, following the direction defined by the gas guide groove, and converges towards the condensation surface.

[0060] After the steam reaches the condensing surface located inside the cover plate, it exchanges heat with the condensing surface, releases latent heat at the condensing surface, and condenses, transforming back into a liquid working fluid. The heat released during the condensation process is conducted through the cover plate to the deheating surface on the other side.

[0061] When the cover plate is equipped with turbulent fins, the single-phase liquid cooling medium flowing through the liquid-cooled circulation cavity forms enhanced convection under the disturbance of the turbulent fins, thereby increasing the convective heat transfer coefficient between the heat dissipation surface and the cooling medium, allowing heat to be carried away quickly. When the cover plate adopts a hollow finned plate structure, the condensation surface area of ​​the two-phase heat exchange cavity is further increased, while the heat dissipation surface area is relatively reduced and no independent turbulent fin structure is set. At this time, the two-phase working fluid in the two-phase heat exchange cavity completes the condensation process on a larger condensation surface. The area of ​​the condensation surface and the heat dissipation surface are more matched, and the heat generated by the chip can still be diffused to the heat dissipation surface through the two-phase phase change cycle and carried away by the single-phase liquid cooling medium flowing through the liquid-cooled circulation cavity, thereby achieving stable and efficient heat dissipation.

[0062] Meanwhile, the liquid working fluid that has condensed in the two-phase heat exchange cavity returns to the storage area near the evaporation surface under the capillary force of the capillary surface layer and the guidance of the reflux wall, thus completing one cycle of evaporation-condensation-reflux. As the chip continues to heat up, the phase change cycle of the two-phase working fluid continues, causing heat to spread horizontally in the two-phase heat exchange cavity and be transferred from the smaller evaporation surface to the larger condensation surface, thereby reducing the heat flux density per unit area.

[0063] Within the liquid-cooled flow chamber, the single-phase liquid cooling medium enters through the inlet, is distributed through the fluid distribution channel, and flows through the first flow channel defined by the turbulent fins. It then enters the second flow channel formed by the second groove and the top plate. Under the action of multiple flow distribution devices (such as guide channels, baffles, and flow-limiting channels), the flow velocity in each channel tends to be uniform, avoiding excessively high or low flow rates in certain areas, thus ensuring the overall heat transfer uniformity of the heat dissipation surface. The cooling medium, after absorbing heat, finally flows out through the outlet and enters the external cooling system to complete heat dissipation.

[0064] Through the above process, the heat sink of this application forms a dual-cycle heat dissipation mechanism that couples an internal two-phase working fluid cycle with an external single-phase liquid cooling cycle, thereby achieving efficient heat diffusion and transfer under high heat flux density conditions.

[0065] It should be noted that although the above embodiments use a chip as a heat source for illustration, the heat sink structure disclosed in this application is not limited to the field of chip heat dissipation. The heat sink of this application is applicable to any heat-generating element or device with high heat flux density or localized hot spots, including but not limited to power devices, laser modules, communication modules, power electronic devices, battery modules, LED light source modules, server computing units, automotive electronic control units, and industrial control equipment.

[0066] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0067] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0068] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A radiator, characterized in that, include: The first cavity structure forms a closed two-phase heat exchange cavity inside, which is encapsulated with a gas-liquid two-phase working fluid for heat diffusion through evaporation and condensation cycles after absorbing heat. The second cavity structure is arranged adjacent to the first cavity structure and forms an independent liquid-cooled flow cavity. The liquid-cooled flow cavity is provided with an inlet port and an outlet port for the single-phase liquid cooling medium to flow in the liquid-cooled flow cavity to remove the heat transferred by the first cavity structure. One side of the first cavity structure forms a thermal contact surface for contacting a heat source and transferring the heat generated by the heat source to the two-phase heat exchange cavity. The opposite side forms an interface heat conduction part, which is located between the two-phase heat exchange cavity and the liquid-cooled flow cavity, and is used to transfer the heat after phase change cycle diffusion in the two-phase heat exchange cavity to the single-phase liquid cooling medium in the liquid-cooled flow cavity.

2. The radiator according to claim 1, characterized in that, Also includes: A substrate in which a first groove and a second groove are formed in sequence along the same opening direction, wherein the opening cross-sectional area of ​​the first groove is smaller than the opening cross-sectional area of ​​the second groove. The first cavity structure consists of the first groove and a cover plate that closes the opening of the first groove to form the two-phase heat exchange cavity therein, wherein the cover plate is the interface heat conduction part; the second cavity structure consists of the cover plate, the second groove, and a top plate that closes the opening of the second groove to form the liquid cooling flow cavity therein.

3. The radiator according to claim 2, characterized in that, The cross-sectional area of ​​the two-phase heat exchange cavity gradually increases from the evaporation surface to the condensation surface along the normal direction, and a liquid storage area is formed near the evaporation surface to accommodate the liquid two-phase working fluid. The remaining space constitutes a reflux zone. A reflux wall is provided in the reflux zone to guide the condensed liquid working fluid back to the liquid storage zone. The evaporation surface is the bottom surface of the first groove, and the condensation surface is the side surface of the cover plate facing the first groove.

4. The radiator according to claim 3, characterized in that, Evaporation fins are provided in the two-phase heat exchange cavity, wherein, The evaporation fins extend from the evaporation surface toward the condensation surface; The evaporation fins extend parallel to the short side of the substrate and are provided with a number of gas guide grooves at intervals parallel to the long side of the substrate to guide the vapor generated by evaporation to expand in a predetermined direction to the condensation surface in the two-phase heat exchange cavity.

5. The radiator according to claim 4, characterized in that, The first groove is also provided with a plurality of support columns, which are welded and fixed to the cover plate, and the evaporation fins are welded and fixed to the cover plate.

6. The radiator according to claim 4, characterized in that, The condensation surface of the cover plate is provided with a plurality of condensation fins. The condensation fins extend in the same direction as the extension direction of the air guide groove, and together with the air guide groove, form a channel structure for guiding the flow of medium vapor and realizing cooling and condensation.

7. The radiator according to claim 6, characterized in that, A turbulent fin is provided on the side of the cover plate away from the first groove. One side of the turbulent fin is welded and fixed to the cover plate, and the other side abuts against the top plate. The top plate, the cover plate and the turbulent fin define the first flow channel of the single-phase liquid in the liquid-cooled flow cavity.

8. The radiator according to claim 6, characterized in that, The cover plate is formed by integral stamping of a thin metal sheet and includes multiple crests and troughs spaced apart along a predetermined direction. The multiple crests and troughs form a hollow cavity facing the evaporation surface. The hollow cavity extends in the same direction as the gas guide groove and together with the gas guide groove, forms a channel structure for guiding the flow of medium vapor and achieving cooling and condensation.

9. The radiator according to claim 8, characterized in that, The side of the cover plate away from the evaporation surface abuts against the top plate, thereby defining a first flow path for the single-phase liquid in the liquid-cooled flow chamber.

10. The radiator according to claim 7 or 9, characterized in that, A second flow channel is also formed within the liquid-cooled flow cavity. The second flow channel is formed by the second groove and the top plate together, and is used to limit the path of the single-phase liquid to the liquid outlet port after flowing through the first flow channel.

11. The radiator according to claim 10, characterized in that, Multiple flow distribution devices are provided in the second flow channel. The multiple flow distribution devices include at least one of the following: a flow guide channel, a partition with partition ribs, a partition without partition ribs, and a flow limiting channel. The flow channel cross-section of the flow guide channel is larger than the standard flow channel cross-section at the flow channel reference plane, and the flow channel cross-section at the flow limiting channel is smaller than the standard flow channel cross-section.

12. The radiator according to any one of claims 6 to 9, 11, characterized in that, The width of the air guide groove is greater than the distance between adjacent evaporation fins.

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