Microchannel phase change cooled heat spreader

Abstract

The application discloses a micro-channel phase change cooling radiator, which comprises a cover plate and a base plate which are connected to each other to form a closed space, a micro-channel group is arranged on the base plate, the cover plate or the base plate is provided with an inlet and an outlet which are away from each other and are used for flowing in and flowing out of a working medium, and a throttling member is arranged on the base plate and is communicated with the inlet and the micro-channel group at two ends; the throttling member is provided with a first flow channel and a second flow channel which is isolated from the first flow channel, and the projection top of the first flow channel on a plane along a first direction is higher than the projection top of the second flow channel; wherein the working medium can flow through the inlet, the first flow channel and the second flow channel, the micro-channel group and the outlet in sequence, and phase change occurs when the working medium flows through the micro-channel group; the base plate is used for absorbing heat of a heat source and exchanging heat with the working medium flowing into the micro-channel group, so that the working medium carries away the heat from the heat source; and the gas backflow and the bubble blockage can be inhibited.

Description

Technical Field

[0001] This application relates to the field of heat dissipation technology, and more particularly to a heat sink with microchannel phase change cooling. Background Technology

[0002] With the continuous development of electronic technology, the integration and performance of electronic devices are constantly improving, leading to a continuous increase in their power and heat flux density. Electronic devices generate enormous amounts of heat during operation. To prevent excessively high temperatures from affecting the performance and operational stability of electronic devices, their temperature must be controlled within a certain range, resulting in increasingly demanding requirements for heat dissipation. For electronic devices with high heat flux densities, especially those exceeding 100 W / cm², traditional high heat flux density electronic packaging cooling solutions, such as air cooling, heat pipes, vapor chambers, and single-phase liquid cooling, have limited cooling capabilities and are gradually becoming insufficient to meet their heat dissipation needs.

[0003] Boiling heat transfer refers to the convective heat transfer process in which heat is transferred from the wall to the liquid, causing the liquid to boil and vaporize. Due to the latent heat of phase change during the boiling process of the refrigerant, boiling heat transfer has the characteristics of small heat transfer temperature difference and high heat transfer intensity. For electronic devices with high heat flux density, heat sinks that combine boiling heat transfer with microchannel cooling technology have great heat dissipation potential.

[0004] In the process of realizing this invention, the inventors discovered at least the following problems in the prior art:

[0005] Under high heat flux density, the large amount of steam generated inside the radiator can easily lead to gas backflow and bubble blockage, affecting the heat dissipation effect of the radiator. Summary of the Invention

[0006] This application provides a microchannel phase change cooling radiator, which can reduce gas backflow and bubble blockage when the radiator dissipates heat under high heat flux density, thus ensuring the heat dissipation effect of the radiator.

[0007] This application provides a microchannel phase change cooling heat sink, including:

[0008] A cover plate and a base plate are interlocked to form a sealed space. The base plate is provided with a microchannel assembly, and the cover plate or the base plate has mutually spaced inlets and outlets for the inflow and outflow of a working fluid.

[0009] A throttling device is disposed on the substrate, and its two ends are respectively connected to the inlet and the microchannel group; the throttling device is provided with a first flow channel and a second flow channel isolated from the first flow channel, and the top of the projection of the first flow channel on the plane along the first direction is higher than the top of the projection of the second flow channel;

[0010] The working fluid, under the action of an external driving force, flows sequentially through the inlet, the first flow channel and the second flow channel, the microchannel group and the outlet, and undergoes a phase change when flowing through the microchannel group;

[0011] The substrate is used to absorb heat from the heat source and exchange heat with the working fluid flowing into the microchannel assembly, so that the working fluid carries away the heat from the heat source during the flow process.

[0012] Furthermore, the side of the cover plate facing the substrate is the bottom surface of the cover plate, and the bottom surface of the cover plate is provided with a substrate mounting groove. The substrate is disposed in the substrate mounting groove, and the bottom surface of the substrate is flush with the bottom surface of the cover plate.

[0013] Furthermore, the bottom surface of the cover plate is also provided with an inlet buffer cavity, a microchannel accommodating cavity, and an outlet buffer cavity;

[0014] The inlet buffer cavity, the microchannel accommodating cavity, and the outlet buffer cavity are sequentially disposed within the substrate mounting groove; the throttling element is also located between the inlet buffer cavity and the microchannel accommodating cavity;

[0015] The inlet buffer chamber is connected to the inlet, the outlet buffer chamber is connected to the outlet, and the microchannel group is also located within the microchannel accommodating cavity; wherein, under the action of an external driving force, the working fluid flows sequentially through the inlet, the inlet buffer chamber, the first flow channel and the second flow channel, the microchannel group, the outlet buffer chamber, and the outlet;

[0016] The side of the cover plate opposite to the bottom surface of the cover plate is the top surface of the cover plate, and the inlet and the outlet are located on the top surface of the cover plate;

[0017] The diameter of the inlet is smaller than the diameter of the outlet.

[0018] Furthermore, the microchannel group includes multiple sets of parallel fin groups;

[0019] Multiple sets of parallel fin groups are arranged side by side on one side of the substrate facing the bottom surface of the cover plate;

[0020] Each set of parallel fin groups consists of two adjacent fins forming a microchannel;

[0021] Each set of parallel fin groups has multiple vaporization cores on its fin surface and on the substrate surface corresponding to each microchannel position.

[0022] Furthermore, the substrate is also provided with a mounting slot;

[0023] The mounting slot is located on the side of the microchannel group near the inlet and is used to mount the throttling element so that the throttling element is fixed to the substrate.

[0024] Furthermore, each of the parallel fin groups is provided with a partition channel between itself and the adjacent parallel fin group, and the width of the partition channel increases with distance from the assembly slot; and

[0025] The substrate surface corresponding to each of the partition channels is provided with multiple vaporization cores.

[0026] Furthermore, the throttling element includes a mounting rib and a throttling body connected to the mounting rib;

[0027] The assembly rib is disposed in the assembly slot, and the throttling body is located between the inlet buffer cavity and the microchannel accommodating cavity; the throttling body is provided with the first flow channel and the second flow channel.

[0028] Furthermore, the hydraulic diameter of the first flow channel is smaller than the hydraulic diameter of the second flow channel;

[0029] The first flow channel and the second flow channel are groove-shaped or perforated.

[0030] Furthermore, the lowest point of the projection of the first flow channel onto the plane along the first direction is lower than the highest point of the projection of the second flow channel.

[0031] Furthermore, the bottom of the projection of the first flow channel onto the plane along the first direction is higher than the top of the projection of the second flow channel.

[0032] As can be seen from the above technical solutions, the embodiments of this application have the following advantages:

[0033] The heat sink provided in this application includes a cover plate and a base plate that are interlocked to form a sealed space. A microchannel group is disposed on the base plate, and the cover plate or base plate has an inlet and an outlet that are far apart from each other for the inflow and outflow of the working fluid. A throttling element is disposed on the base plate, with its two ends connected to the inlet and the microchannel group, respectively. The throttling element has a first flow channel and a second flow channel isolated from the first flow channel, and the top of the projection of the first flow channel on a plane along a first direction is higher than the top of the projection of the second flow channel. The working fluid can flow sequentially through the inlet, the first flow channel, the second flow channel, the microchannel region, and the outlet, and undergoes a phase change when flowing through the microchannel group. The base plate is used to absorb heat from the heat source and exchange heat with the working fluid flowing into the microchannel group, so that the working fluid carries away heat from the heat source during its flow. Because the throttling device is equipped with a first flow channel and a second flow channel, and the top of the projection of the first flow channel on the plane along the first direction is higher than the top of the projection of the second flow channel, the working fluid flowing into the microchannel group from the second flow channel first fills the lower region of the microchannel group, preventing evaporation. The working fluid flowing into the microchannel group from the first flow channel can disperse the bubbles accumulated in the upper region of the microchannel group, thereby suppressing bubble blockage. At the same time, the working fluid flowing into the microchannel group from the first flow channel can push the gas accumulated in the upper region of the microchannel group to the outlet, thereby suppressing the backflow of gas generated by phase change. Through the first and second flow channels of the throttling device, the gas backflow and bubble blockage of the radiator under high heat flux density can be effectively reduced, thereby ensuring the heat dissipation effect of the radiator. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0035] Figure 1 This is a schematic diagram of the structure of the heat sink disclosed in an embodiment of this application;

[0036] Figure 2 This is a schematic diagram of the structure of the cover plate disclosed in an embodiment of this application;

[0037] Figure 3 This is a cross-sectional schematic diagram of the cover plate disclosed in an embodiment of this application;

[0038] Figure 4 This is another structural schematic diagram of the cover plate disclosed in the embodiments of this application;

[0039] Figure 5 This is a schematic diagram of the structure of the substrate disclosed in an embodiment of this application;

[0040] Figure 6 This is another schematic diagram of the substrate structure disclosed in the embodiments of this application;

[0041] Figure 7 This is a schematic diagram of the throttling device disclosed in an embodiment of this application;

[0042] Figure 8 This is another structural schematic diagram of the throttling device disclosed in the embodiments of this application. Detailed Implementation

[0043] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0044] In the description of the embodiments of this application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of 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. Therefore, they should not be construed as limitations on the embodiments of this application.

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

[0046] With the continuous development of electronic technology, the integration and performance of electronic devices are constantly improving, leading to a continuous increase in their power and heat flux density. Electronic devices generate enormous amounts of heat during operation. To prevent excessively high temperatures from affecting the performance and operational stability of electronic devices, their temperature must be controlled within a certain range, resulting in increasingly demanding requirements for heat dissipation. For electronic devices with high heat flux densities, especially those exceeding 100 W / cm², traditional high heat flux density electronic packaging cooling solutions, such as air cooling, heat pipes, vapor chambers, and single-phase liquid cooling, have limited cooling capabilities and are gradually becoming insufficient to meet their heat dissipation needs.

[0047] Existing single-phase liquid cooling plate technology suffers from poor heat transfer between the cold plate channels, and the inlet and outlet are relatively far apart. Therefore, the temperature gradually rises along the direction of liquid flow, resulting in a significant temperature difference between the chip and inlet, particularly at the inlet and outlet. In electronic devices, this manifests as a pronounced hot and cold temperature distribution and poor temperature uniformity. Furthermore, to meet the high heat flux density requirements for cooling, a large flow rate of cooling fluid is needed to control the temperature of the electronic device, inevitably increasing system power consumption. For electronic devices with high heat flux densities, existing single-phase liquid cooling plates tend to cause significant temperature differences when dissipating heat, which is detrimental to the stable operation of the electronic device.

[0048] Meanwhile, existing liquid cooling technologies include not only single-phase liquid cooling but also two-phase cooling. Compared to single-phase liquid cooling, two-phase cooling utilizes the latent heat of refrigerant boiling heat transfer. Boiling heat transfer refers to the convective heat transfer process where heat is transferred from the wall to the liquid, causing the liquid to boil and vaporize. Due to the latent heat of phase change during refrigerant boiling, boiling heat transfer has the characteristics of small temperature difference and high heat transfer intensity. For electronic devices with high heat flux density, microchannel heat sinks combining boiling heat transfer and microchannel cooling technology have great heat dissipation potential. However, such microchannel heat sinks are prone to generating large amounts of vapor under high heat flux density, which can easily lead to gas backflow and bubble blockage within the heat sink, affecting its heat dissipation effect.

[0049] To address the problem that under high heat flux density, the large amount of steam (gas) generated within the radiator can easily lead to gas backflow and bubble blockage, thus affecting the radiator's heat dissipation effect, embodiments of this application provide a microchannel phase change cooling radiator, such as... Figure 1 as well as Figure 7 As shown, the specific structure is as follows:

[0050] The heat sink includes a cover plate 1, a throttling element 2, and a substrate 3. The heat source is located on one side of the substrate 3, i.e., on one side of the heat sink. Specifically, the heat source can be located at the bottom of the substrate 3, i.e., at the bottom of the heat sink, and the bottom of the substrate 3 can be directly attached to the heat source, or the bottom of the substrate 3 can be at a preset distance from the heat source. This preset distance can be adjusted according to actual needs and is not specifically limited. To ensure heat dissipation effect, the preset distance should not be too large. Preferably, the bottom of the substrate 3 is directly attached to the heat source, in which case the heat sink's heat dissipation effect is optimal. The installation relationship between the substrate 3 and the heat source is not specifically limited. The heat source can be electronic equipment or other devices requiring heat dissipation; this is not specifically limited here. This application describes a high heat flux density electronic device as the heat source, and will not be elaborated further below.

[0051] The substrate 3 is embedded on one side of the cover plate 1. The cover plate 1 and the substrate 3 are interlocked to form a sealed space, that is, the cover plate 1 and the substrate 3 can be firmly connected, and the cover plate 1 and the substrate 3 cooperate with each other to form a sealed space. The substrate 3 is provided with a microchannel group 32, which can be understood as a microchannel region with multiple vaporization nuclei. When the working fluid enters the microchannel group 32, the working fluid will come into contact with the surface of the microchannel group 32. The working fluid can be understood as a refrigerant. The working fluid can absorb heat from the heat source from the microchannel group 32 and change into a gaseous working fluid (gas). The cover plate 1 or the substrate 3 is provided with an inlet 11 and an outlet 12, which are far apart from each other for the inflow and outflow of the working fluid. Generally, the inlet 11 is located on one side of the microchannel group 32, for example, on the cover plate 1, and the outlet 12 is located on the other side of the microchannel group 32, for example, on the cover plate 1. That is, the inlet 11 is arranged on one side of the microchannel group 32, and the outlet 12 is arranged on the other side. The inlet 11 can be used to input the working fluid, and the outlet 12 can be used to output the working fluid. The throttling element 2 of the radiator is set on the substrate 3. The throttling element 2 can be partially embedded in the substrate 3, and the throttling element 2 is also located between the inlet 11 and the microchannel group 32, that is, the two ends of the throttling element 2 are respectively connected to the inlet 11 and the microchannel group 32. The setting of the throttling element 2 is beneficial to increase the inlet pressure head (which can be understood as increasing the working fluid flow rate, because the flow area of ​​the throttling element is small, the resistance to liquid flow is large, so the pressure drop is large, thereby obtaining a larger flow rate). The throttling element 2 is provided with two flow channels, such as Figure 7 As shown, the first flow channel 21 and the second flow channel 22 are respectively used for supplying working fluid into the microchannel assembly 32. The second flow channel 22 is isolated from the first flow channel 21, and the top of the projection of the first flow channel 21 onto a plane along a first direction is higher than the top of the projection of the second flow channel 22. The first direction refers to the direction perpendicular to the side of the substrate 3 where the microchannel assembly 32 is located and extending towards the cover plate 1. Figure 1 as well as Figure 7Using the indicated direction as a reference, the working fluid flowing through the second flow channel 22 into the microchannel group 32 first fills the lower region of the microchannel group 32 to prevent the microchannel group 32 from drying out. The working fluid flowing through the first flow channel 21 into the microchannel group 32 can push the gas (gaseous working fluid) generated by the phase change towards the outlet 12, thereby suppressing the backflow of the gas generated by the phase change. Furthermore, since the top of the projection of the first flow channel 21 on the plane along the first direction is higher than the top of the projection of the second flow channel 22, the working fluid flowing through the first flow channel 21 into the microchannel group 32 can push the gas (gaseous working fluid) of the microchannel group 32 towards the outlet 12. It can also quickly disperse the bubbles accumulated in the upper region of the microchannel group 32, which is more conducive to pushing the gas (i.e., the gaseous working fluid) accumulated in the microchannel group 32 towards the outlet 12, thereby suppressing the bubble blockage phenomenon.

[0052] The working fluid, under the action of an external driving force, flows sequentially through inlet 11, first flow channel 21, second flow channel 22, microchannel group 32, and outlet 12, undergoing a phase change while flowing through microchannel group 32. The working fluid enters through inlet 11, passes through the first and second flow channels 21 and 22 of the throttling device 2, and enters microchannel group 32, contacting its surface. The working fluid absorbs heat from the heat source on the surface of microchannel group 32 and undergoes a phase change to gas (gaseous working fluid). The substrate 3 absorbs heat from the heat source and exchanges heat with the working fluid flowing into microchannel group 32, allowing the working fluid to carry away heat from the heat source during its flow. It is understood that the working fluid in the radiator of this application embodiment operates as follows: when the radiator is working, heat is transferred from the electronic device to the substrate 3 of the radiator. The liquid working fluid enters the radiator from the inlet 11 under the action of an external driving force (such as a compressor or a circulating pump). When the working fluid enters the microchannel group 32 through the throttling device 2, the liquid working fluid and the microchannel group 32 on the substrate 3 come into full contact. The liquid working fluid absorbs heat rapidly, undergoes boiling heat exchange and generates a large number of bubbles. Under the pressure difference, the gas (gaseous working fluid) flows out from the outlet 12, thereby carrying away the heat from the heat source.

[0053] As can be seen, the heat sink provided in this application embodiment includes a cover plate and a base plate that are interlocked to form a sealed space. A microchannel group is provided on the base plate, and the cover plate or base plate is provided with an inlet and an outlet that are far apart from each other for the working fluid to flow in and out. A throttling element is provided on the base plate, and its two ends are respectively connected to the inlet and the microchannel group. The throttling element is provided with a first flow channel and a second flow channel that is isolated from the first flow channel. The top of the projection of the first flow channel on the plane along the first direction is higher than the top of the projection of the second flow channel. The working fluid can flow through the inlet, the first flow channel and the second flow channel, the microchannel area and the outlet in sequence, and undergo a phase change when flowing through the microchannel group. The base plate is used to absorb the heat from the heat source and exchange heat with the working fluid flowing into the microchannel group, so that the working fluid carries away the heat from the heat source during the flow process. Because the throttling device is equipped with a first flow channel and a second flow channel, and the top of the projection of the first flow channel on the plane along the first direction is higher than the top of the projection of the second flow channel, the working fluid flowing into the microchannel group from the second flow channel first fills the lower region of the microchannel group, preventing evaporation. The working fluid flowing into the microchannel group from the first flow channel can disperse the bubbles accumulated in the upper region of the microchannel group, thereby suppressing bubble blockage. At the same time, the working fluid flowing into the microchannel group from the first flow channel can push the gas accumulated in the upper region of the microchannel group to the outlet, thereby suppressing the backflow of gas generated by phase change. Through the first and second flow channels on the throttling device, the backflow of gas and bubble blockage of the radiator under high heat flux density can be effectively reduced, thereby ensuring the heat dissipation effect of the radiator. The heat sink provided in this application embodiment is used for heat dissipation of electronic devices with high heat flux density. The heat sink for electronic devices with high heat flux density can be arranged at the bottom of the substrate or other locations, and has versatility. It can achieve cooling of electronic devices with high heat flux density by using the latent heat of phase change of the working fluid based on the combination of flow boiling heat transfer and microchannels. Furthermore, since the heat sink provided in this application embodiment can effectively solve the problems of gas backflow and bubble blockage in heat sinks under high heat flux density, the heat dissipation effect of the heat sink provided in this application embodiment is guaranteed, thereby effectively meeting the heat dissipation requirements of electronic devices with high heat flux density.

[0054] Furthermore, the lowest point of the projection of the first flow channel 21 onto the plane along the first direction is lower than the highest point of the projection of the second flow channel 22; that is, a portion of the projection of the first flow channel 21 onto the plane along the first direction is higher than the highest point of the projection of the second flow channel 22, and another portion of the projection of the first flow channel 21 onto the plane along the first direction is lower than the highest point of the projection of the second flow channel 22; or,

[0055] The lowest point of the projection of the first flow channel 21 onto the plane along the first direction is higher than the highest point of the projection of the second flow channel 22; that is, the overall projection of the first flow channel 21 onto the plane along the first direction is higher than the highest point of the projection of the second flow channel 22. Preferably, the highest point of the projection of the first flow channel 21 onto the plane along the first direction is higher than the highest point of the projection of the second flow channel 22, and the lowest point of the projection of the first flow channel 21 onto the plane along the first direction is also higher than the highest point of the projection of the second flow channel 22. In this case, the effect of suppressing gas backflow and suppressing bubble blockage is optimal.

[0056] Furthermore, to address the gas backflow problem, embodiments of this application provide a radiator cover and a throttling device, such as... Figure 2 , Figure 3 as well as Figure 4 As shown, the details are as follows:

[0057] The heat sink cover 1 includes a cover bottom surface 14 and a substrate mounting groove 15. The cover bottom surface 14 is the side of the cover 1 facing the substrate 3. The cover bottom surface 14 is provided with the substrate mounting groove 15, and the heat sink substrate 3 is disposed in the substrate mounting groove 15, with the bottom surface of the substrate 3 flush with the cover bottom surface 14. It is understood that with the substrate mounting groove 15 on the cover bottom surface 14, after the cover 1 and substrate 3 are fully secured, the cover bottom surface 14 of the cover 1 and the bottom surface of the substrate 3 are completely flush.

[0058] The cover plate 1 also includes: a top surface 13, an inlet buffer cavity 16, a microchannel accommodating cavity 17, and an outlet buffer cavity 18; the top surface 13 and the bottom surface 14 of the cover plate are arranged opposite to each other, that is, the side of the cover plate 1 that is away from the bottom surface 14 of the cover plate is the top surface 13 of the cover plate, the inlet 11 and the outlet 12 are arranged on the top surface 13 of the cover plate, and the inlet 11 and the outlet 12 are generally arranged at both ends of the top surface 13 of the cover plate. The inlet buffer chamber 16, the microchannel receiving chamber 17, and the outlet buffer chamber 18 are disposed on the bottom surface 14 of the cover plate, meaning the bottom surface 14 of the cover plate also has an inlet buffer chamber, a microchannel receiving chamber, and an outlet buffer chamber. The inlet buffer chamber 16 is located at the inlet section of the inlet 11, the outlet buffer chamber 18 is located at the outlet section of the outlet 12, and the microchannel receiving chamber 17 is located in the intermediate area between the inlet section and the outlet section. In other words, the inlet buffer chamber 16, the microchannel receiving chamber 17, and the outlet buffer chamber 18 are sequentially disposed within the substrate mounting groove 15. The throttling element 2 is disposed on the substrate 3, and the throttling element 2 is also located between the inlet buffer chamber 16 and the microchannel receiving chamber 17. It can be understood that the inlet buffer chamber 16 is connected to the inlet 11 and is used to buffer the working fluid entering the radiator from the inlet 11. The outlet buffer chamber 18 is connected to the outlet 12 and is used to buffer the working fluid flowing out of the microchannel assembly 32, further balancing the internal air pressure of the radiator. The microchannel assembly 32 is also located within the microchannel receiving cavity 17, meaning the microchannel receiving cavity 17 can be used to house the microchannel assembly 32. Under the action of an external driving force, the working fluid flows sequentially through the inlet 11, the inlet buffer cavity 16, the first flow channel 21, the second flow channel 22, the microchannel assembly 32, the outlet buffer cavity 18, and the outlet 12. Specifically, the working fluid enters the radiator from the inlet 11, is buffered by the inlet buffer cavity 16, and then enters the microchannel assembly 32 through the throttling device 2. The working fluid comes into full contact with the microchannel assembly 32, and the liquid working fluid rapidly absorbs heat, undergoes boiling heat exchange, and generates a large number of bubbles. Driven by the pressure difference, these bubbles converge into the outlet buffer cavity 18 and then flow out from the outlet 12. The diameter of the inlet 11 on the cover plate 1 is smaller than the diameter of the outlet 12, making it easier for the liquid working fluid to flow out from the outlet 12 after absorbing heat and undergoing a phase change from liquid to gas, thereby further reducing the risk of gas backflow from the radiator.

[0059] Furthermore, to address the issue of flow instability, embodiments of this application provide a substrate for a heat sink, such as... Figure 5 as well as Figure 6 As shown, the details are as follows:

[0060] The microchannel group 32 includes multiple sets of parallel fin groups 33. Each set of parallel fin groups 33 has multiple fins, and the number of fins in each set of parallel fin groups 33 can be the same or different, which is not limited here. The multiple sets of parallel fin groups 33 are arranged side by side on the side of the substrate 3 facing the bottom surface 14 of the cover plate. Two adjacent fins of each set of parallel fin groups 33 form a microchannel. Multiple vaporization nuclei are provided on the surface of each fin and on the substrate surface of the substrate 3 corresponding to each microchannel position. Each vaporization nucleus is a pit, and the working fluid can undergo phase change and absorb heat on the vaporization nuclei to generate bubbles. It can be seen that multiple sets of parallel fin groups 33 are arranged in the middle area of ​​the substrate 3, and microchannels are formed between two adjacent fins of each set of parallel fin groups 33, thus forming a microchannel group 32 as a whole. The channel surface of the microchannel group 32 has a large number of vaporization nuclei, thereby enhancing boiling heat transfer. Here, the channel surface refers to the fin surface of the parallel fin group 33. That is, the fin surface of each parallel fin group 33 and the substrate surface of the substrate 3 corresponding to each microchannel position are provided with multiple vaporization cores. In other words, there are vaporization cores on the contact surface between the working fluid and the solid in the microchannel group 32.

[0061] The substrate 3 is also provided with a mounting slot (throttling element mounting slot) 31; the mounting slot 31 is provided on the side of the microchannel assembly 32 near the inlet 11, and is used to mount the throttling element 2 so that the throttling element 2 is fixed to the substrate 3. It can be understood that the mounting slot 31 is provided on the side of the microchannel assembly 32 near the inlet buffer cavity 16, so as to embed the throttling element 2 into the substrate 3. In the multiple parallel fin groups 33, each parallel fin group 33 is provided with a partition channel 34 between it and the adjacent parallel fin group 33. The width of the partition channel 34 increases as it is further away from the assembly slot 31. The substrate 3 surface corresponding to each partition channel 34 position is provided with multiple vaporization cores. Each vaporization core is a pit. That is, in the microchannel group 32, a partition channel 34 is provided between every two adjacent parallel fin groups 33. The width of the partition channel 34 gradually increases along the fluid flow direction to buffer the liquid, balance the pressure between the channels, and thus suppress flow instability.

[0062] Furthermore, embodiments of this application provide a throttling element for the heat sink, such as... Figure 8 As shown, the details are as follows:

[0063] The throttling device 2 includes: an assembly rib 23 and a throttling body connected to the assembly rib; the assembly rib 23 of the throttling device 2 is disposed in the assembly slot 31, and the throttling body is located between the inlet buffer chamber 16 and the microchannel receiving chamber 17. A first flow channel 21 and a second flow channel 22 are provided on the throttling body. The first flow channel 21 is located above the second flow channel 22, and the hydraulic diameter of the first flow channel 21 is smaller than the hydraulic diameter of the second flow channel 22. The first flow channel 21 and the second flow channel 22 can be groove-shaped or perforated, and the specific shape of the groove and the perforation is not limited here. When the first flow channel 21 and the second flow channel 22 are groove-shaped, the groove height of the first flow channel 21 is lower than the groove height of the second flow channel 22, thereby allowing more working fluid to enter the microchannel group 32 from the second flow channel 22. The second flow channel 22 enables the working fluid to quickly enter the microchannel group 32 and fill the bottom of the microchannel group 32, thereby effectively preventing evaporation.

[0064] As can be seen, in this embodiment, the inlet diameter of the radiator is smaller than the outlet diameter, which facilitates the smooth discharge of gas (gaseous working fluid) from the outlet and suppresses gas backflow. The throttling device between the microchannel group and the inlet helps increase the inlet pressure head. The second flow channel facilitates the rapid entry of the working fluid into the microchannel group, first filling the lower region of the microchannel group to prevent evaporation and suppressing the backflow of gas generated by phase change. The working fluid flowing through the first flow channel into the microchannel group helps to push the gas accumulated in the upper region of the microchannel group towards the outlet and can disperse the bubbles accumulated in the upper region of the microchannel group, thereby suppressing bubble blockage. In the microchannel group, the gas increases along the flow direction. The partition channel between adjacent parallel fin groups and the width of the partition channel gradually increases along the flow direction, which helps to balance the pressure between the channels and plays a buffering role, thereby suppressing flow instability. By using flow boiling heat transfer technology combined with microchannel technology to cool electronic devices with high heat flux density, efficient heat dissipation with a small flow rate of refrigerant is achieved while meeting temperature control requirements, and problems such as gas backflow, bubble blockage, and flow instability are solved.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of this application, and not to limit them; although the embodiments of this application have been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of the embodiments of this application.

Claims

1. A micro-channel phase change cooling heat spreader, characterized by, The utility model relates to a microchannel heat sink, comprising: a cover plate and a substrate which are connected by mutual engagement to form a closed space, the substrate is provided with a microchannel group, and the cover plate or the substrate is provided with an inlet and an outlet which are away from each other for the working medium to flow in and out; and a throttling element which is arranged on the substrate and is in communication with the inlet and the microchannel group at both ends, the throttling element is provided with a first flow channel and a second flow channel which is isolated from the first flow channel, and the topmost part of the projection of the first flow channel on a plane along a first direction is higher than the topmost part of the projection of the second flow channel; wherein the working medium flows through the inlet, the first flow channel and the second flow channel, the microchannel group and the outlet in sequence under the action of an external driving force, and undergoes a phase change when flowing through the microchannel group; the substrate is used to absorb heat from a heat source and exchange heat with the working medium flowing into the microchannel group, so that the working medium carries away heat from the heat source during the flow process.

2. The heat spreader of claim 1, wherein, the side of the cover plate facing the substrate is a cover plate bottom surface, the cover plate bottom surface is provided with a substrate assembly groove, the substrate is arranged in the substrate assembly groove, and the bottom surface of the substrate is flush with the cover plate bottom surface.

3. The heat sink of claim 2, wherein, the cover plate bottom surface is also provided with an inlet buffer cavity, a microchannel accommodating cavity and an outlet buffer cavity; the inlet buffer cavity, the microchannel accommodating cavity and the outlet buffer cavity are arranged in the substrate assembly groove in sequence; the throttling element is also located between the inlet buffer cavity and the microchannel accommodating cavity; the inlet buffer cavity is in communication with the inlet, the outlet buffer cavity is in communication with the outlet, and the microchannel group is located in the microchannel accommodating cavity; wherein the working medium flows through the inlet, the inlet buffer cavity, the first flow channel and the second flow channel, the microchannel group, the outlet buffer cavity and the outlet in sequence under the action of an external driving force; the side of the cover plate away from the cover plate bottom surface is a cover plate top surface, the inlet and the outlet are arranged on the cover plate top surface; the diameter of the inlet is smaller than the diameter of the outlet.

4. The heat sink of claim 3, wherein, the microchannel group comprises a plurality of parallel fin groups; a plurality of the parallel fin groups are arranged side by side on the side of the substrate facing the cover plate bottom surface; two adjacent fins of each parallel fin group form a microchannel; the surface of each parallel fin group and the surface of the substrate corresponding to the position of each microchannel are provided with a plurality of vaporization cores.

5. The heat sink of claim 4, wherein, the substrate is also provided with an assembly clamping groove; the assembly clamping groove is arranged on the side of the microchannel group close to the inlet, and is used to assemble the throttling element, so that the throttling element is fixed to the substrate.

6. The heat sink of claim 5, wherein, a partition channel is arranged between each parallel fin group and the adjacent parallel fin group, and the farther the partition channel is from the assembly clamping groove, the wider the partition channel is; and the surface of the substrate corresponding to the position of each partition channel is provided with a plurality of vaporization cores.

7. The heat sink of claim 5, wherein, the throttling element comprises an assembly rib column and a throttling main body part connected with the assembly rib column; The assembly rib column is arranged in the assembly clamping groove, and the throttling main body part is located between the inlet buffer cavity and the micro-channel accommodating cavity; the throttling main body part is provided with the first flow passage and the second flow passage.

8. The heat spreader of claim 1, wherein, The hydraulic diameter of the first flow passage is smaller than the hydraulic diameter of the second flow passage. The first flow passage and the second flow passage are in the form of grooves or holes.

9. The heat spreader of claim 1, wherein, The lowest part of the projection of the first flow passage on a plane along the first direction is lower than the highest part of the projection of the second flow passage.

10. The heat spreader of claim 1, wherein, The lowest part of the projection of the first flow passage on a plane along the first direction is higher than the highest part of the projection of the second flow passage.

Images