A microchannel phase change radiator

Abstract

A microchannel phase change heat sink provided by the present invention comprises an upper cover, a first capillary wick, a second capillary wick and a lower cover, wherein the first capillary wick covers the liquid cavity of the upper cover, and the end of the first capillary wick away from the upper cover has a plurality of porous micro-columns arranged at intervals, the second capillary wick is connected to the porous micro-columns, the gaps between the plurality of porous micro-columns form a steam containing space, the steam containing space is connected to the steam cavity of the upper cover, the lower cover is provided on the liquid cavity and the steam cavity, the end of the lower cover away from the upper cover is used for bonding the chip, the lower cover is made of a heat-conducting material, the liquid cavity is used for accommodating a liquid working medium, the present application covers the liquid cavity by the first capillary wick, thereby separating the liquid cavity from the steam cavity, so that the liquid working medium in the liquid cavity will not flow into the steam cavity, and the steam in the steam cavity will not pass through the first capillary wick into the liquid cavity, so that the present application realizes the vapor-liquid separation in the phase change heat dissipation process, eliminates the instability of the vapor-liquid two-phase flow, and improves the stability of the microchannel phase change heat sink.

Description

Technical Field

[0001] The invention relates to the field of thermal management of high heat flux density chips, and in particular to a microchannel phase change radiator. Background Art

[0002] After entering the 21st century, big data, cloud computing and artificial intelligence technologies have developed rapidly. As the core key, the computing power of chips has been continuously improved. The problem of heat generation during operation has become prominent, and the average heat flux density has exceeded 100W / cm2, and local hot spots can reach 400W / cm2. Microchannel phase change heat dissipation technology is currently the best way to solve the heat dissipation problem of ultra-high heat flux density chips. However, during the microchannel phase change heat dissipation process, the liquid forms a vapor core in a narrow channel of tens to hundreds of microns and gradually grows into a narrow bubble, forming a two-phase flow state in which vapor and liquid coexist in the microchannel, which can easily lead to unstable vapor-liquid two-phase flow, thereby inducing pipeline vibration and local dry burning, posing a huge threat to the stability of the cooling system and the chip. On the other hand, since the outlet of the microchannel radiator is a vapor-liquid two-phase flow, it will cause cavitation in the pump that cooperates with the microchannel radiator, or cause the compressor that cooperates with the microchannel radiator to run with liquid and be damaged. Summary of the invention

[0003] Based on this, the main purpose of the present invention is to provide a microchannel phase change heat sink that can achieve vapor-liquid separation during the phase change heat dissipation process.

[0004] To achieve the above object, the present invention provides a microchannel phase change heat sink, comprising:

[0005] The upper cover is provided with a liquid cavity and a steam cavity which are arranged at intervals, the upper cover is also provided with a liquid inlet and a liquid outlet which are communicated with the liquid cavity, and the upper cover is also provided with a steam outlet which is communicated with the steam cavity;

[0006] A first capillary wick is connected to the upper cover and covers the liquid cavity. An end of the first capillary wick away from the upper cover has a plurality of porous micro-columns arranged at intervals. Gaps between the plurality of porous micro-columns form a vapor storage space, and the vapor storage space is connected to the vapor cavity.

[0007] A second capillary core is connected to the porous microcolumn, wherein the first capillary core and the second capillary core are both porous media; and

[0008] A lower cover, which is disposed on the liquid cavity and the vapor cavity, and one end of the lower cover facing the upper cover is connected to the second capillary wick, and one end of the lower cover away from the upper cover is used for bonding the chip, and the lower cover is made of a heat-conducting material;

[0009] The liquid cavity is used to accommodate a liquid working medium. The liquid working medium flows into the liquid cavity through the liquid inlet and then flows out to the outside through the liquid outlet. The liquid working medium in the liquid cavity can flow into the second capillary wick through the first capillary wick and the porous microcolumns of the first capillary wick. The chip can diffuse heat into the second capillary wick through the lower cover, so that the liquid working medium in the second capillary wick evaporates and changes phase to form steam, and then the steam enters the steam holding space and is discharged to the outside through the steam cavity and the steam outlet.

[0010] Preferably, a plurality of the porous micro-columns are evenly spaced and arranged on the first capillary core.

[0011] Preferably, the first capillary core and the second capillary core are integrally formed.

[0012] Preferably, the average pore size of the first capillary core is 10-50 μm, and the average pore size of the second capillary core is 1-5 μm.

[0013] Preferably, the porous microcolumn is in the shape of a square column or a cylinder.

[0014] Preferably, the lower cover is provided with a first accommodating groove, and the first accommodating groove is used for accommodating the second capillary core.

[0015] Preferably, the upper cover is provided with a second accommodating groove, and the second accommodating groove is used for accommodating the first capillary core.

[0016] Preferably, the upper cover is provided with a third accommodating groove, and the third accommodating groove is used to accommodate the lower cover.

[0017] Preferably, both the first capillary wick and the second capillary wick are porous media prepared from metal powder.

[0018] Preferably, the metal powder is one or more of copper powder, nickel powder and aluminum powder.

[0019] The advantages of the technical solution of the present invention are as follows: when the chip needs to be cooled, the lower cover is fitted with the chip, and the heat released during the operation of the chip is diffused into the second capillary wick through the lower cover, so that the liquid working medium in the second capillary wick evaporates and changes phase to form steam, and then the steam enters the steam storage space and is discharged to the outside through the steam cavity and the steam outlet, thereby achieving the heat dissipation of the chip. At the same time, the external liquid working medium flows into the liquid cavity through the liquid inlet and then flows out to the outside through the liquid outlet. In this process, the liquid working medium in the liquid cavity flows into the second capillary wick through the first capillary wick and the porous microcolumns of the first capillary wick to replenish the liquid working medium to the second capillary wick. Since the porous medium has a vapor after absorbing the liquid, The first capillary wick covers the liquid cavity, thereby separating the liquid cavity from the vapor cavity, so that the liquid working medium in the liquid cavity will not flow into the vapor cavity, and the vapor in the vapor cavity cannot pass through the first capillary wick into the liquid cavity, so that the liquid working medium can only be discharged to the outside through the liquid outlet, and the vapor can only be discharged to the outside through the vapor outlet. Therefore, the present application realizes the vapor-liquid separation in the phase change heat dissipation process, eliminates the instability of the vapor-liquid two-phase flow, and improves the stability of the microchannel phase change radiator; it avoids the cavitation of the pump or the damage of the compressor with liquid that cooperates with the microchannel radiator. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the devices shown in these drawings without paying creative work.

[0021] Figure 1 An exploded view of a microchannel phase change heat sink according to an embodiment;

[0022] Figure 2 This is a schematic structural diagram of an upper cover according to an embodiment;

[0023] Figure 3 A top view of a microchannel phase change heat sink according to an embodiment;

[0024] Figure 4 for Figure 3 AA section view;

[0025] Figure 5 for Figure 3 BB section view;

[0026] Figure 6 This is the working principle diagram of the microchannel phase change radiator.

[0027] Among them, 100. upper cover; 110. liquid cavity; 120. vapor cavity; 130. liquid inlet; 140. liquid outlet; 150. vapor outlet; 160. second accommodating groove; 170. third accommodating groove; 180. fastening screw hole; 200. first capillary core; 210. porous microcolumn; 220. vapor storage space; 300. second capillary core; 400. lower cover; 410. first accommodating groove.

[0028] 1. Liquid working fluid flow direction; 2. Steam flow direction.

[0029] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly. In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In addition, "and / or" in the full text includes three solutions. Taking A and / or B as an example, it includes A technical solution, B technical solution, and A and B technical solutions that meet both requirements. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0032] A microchannel phase change heat sink according to a preferred embodiment of the present invention is used to achieve high heat flux density chip heat dissipation.

[0033] The porous medium has liquid permeability and gas isolation properties after the porous medium absorbs liquid, so that the liquid can flow in the porous medium, and after the porous medium absorbs liquid, the gas cannot enter the porous medium from the outside of the porous medium, but the gas can diffuse from the inside of the porous medium to the outside of the porous medium.

[0034] like Figure 1-5 As shown, a microchannel phase change heat sink includes an upper cover 100, a first capillary wick 200, a second capillary wick 300 and a lower cover 400. The upper cover 100 is provided with a liquid cavity 110 and a vapor cavity 120 arranged at intervals. The upper cover 100 is also provided with a liquid inlet 130 and a liquid outlet 140 connected to the liquid cavity 110. The upper cover 100 is also provided with a vapor outlet 150 connected to the vapor cavity 120. The first capillary wick 200 is connected to the upper cover 100, and the first capillary wick 200 covers the liquid cavity 110. The end of the first capillary wick 200 away from the upper cover 100 has a plurality of porous microcolumns 210 arranged at intervals. The second capillary wick 300 is connected to the porous microcolumns 210. The gaps between the plurality of porous microcolumns 210 form a vapor space 220. The vapor space 220 is connected to the vapor cavity 120. The first capillary wick 200 and the second capillary wick 300 All of them are porous media. The lower cover 400 is arranged on the liquid cavity 110 and the vapor cavity 120, and one end of the lower cover 400 facing the upper cover 100 is connected to the second capillary wick 300. The end of the lower cover 400 away from the upper cover 100 is used to fit the chip. The lower cover 400 is made of heat-conducting material. The liquid cavity 110 is used to accommodate liquid working medium. The liquid working medium flows into the liquid cavity 110 through the liquid inlet 130 and then flows out to the outside through the liquid outlet 140. The liquid working medium in the liquid cavity 110 can flow into the second capillary wick 300 through the first capillary wick 200 and the porous microcolumns 210 of the first capillary wick 200. The chip can diffuse heat to the second capillary wick 300 through the lower cover 400, so that the liquid working medium in the second capillary wick 300 evaporates and changes phase to form steam, and then the steam enters the steam holding space 220 and is discharged to the outside through the steam cavity 120 and the steam outlet 150.

[0035] When the chip needs to be cooled, the lower cover 400 is attached to the chip, and the heat released during the operation of the chip is diffused into the second capillary wick 300 through the lower cover 400, so that the liquid working medium in the second capillary wick 300 evaporates and changes phase to form steam, and then the steam enters the steam holding space 220, and is discharged to the outside through the steam cavity 120 and the steam outlet 150, thereby achieving the heat dissipation of the chip. At the same time, the external liquid working medium flows into the liquid cavity 110 through the liquid inlet 130, and then flows out to the outside through the liquid outlet 140. In this process, the liquid working medium in the liquid cavity 110 flows into the second capillary wick 300 through the first capillary wick 200 and the porous microcolumns 210 of the first capillary wick 200, so as to replenish the liquid working medium for the second capillary wick 300. Since the porous medium has a vapor insulation after absorbing liquid, Characteristics, so that the steam diffused into the steam containing space 220 or the steam cavity 120 will not flow back into the steam containing space 220 again, and because the first capillary core 200 covers the liquid cavity 110, the liquid cavity 110 is separated from the steam cavity 120, so that the liquid working medium in the liquid cavity 110 will not flow into the steam cavity 120, and the steam in the steam cavity 120 cannot pass through the first capillary core 200 to enter the liquid cavity 110, so that the liquid working medium can only be discharged to the outside through the liquid outlet 140, and the steam can only be discharged to the outside through the steam outlet 150, so that the present application realizes the vapor-liquid separation in the phase change heat dissipation process, eliminates the instability of the vapor-liquid two-phase flow, and improves the stability of the microchannel phase change radiator; avoids the cavitation of the pump or the liquid damage of the compressor matched with the microchannel radiator.

[0036] In this embodiment, the lower cover 400 is fitted with the packaging shell of the chip. In other embodiments, the packaging shell of the chip is directly set as the lower cover 400, which is equivalent to omitting the lower cover. As a result, the heat released during the operation of the chip is directly diffused to the second capillary core 300 through the packaging shell of the chip, thereby effectively reducing the interface thermal resistance and contact thermal resistance during the heat transfer process.

[0037] In this embodiment, the liquid inlet 130 and the liquid outlet 140 are located on two opposite sides of the upper cover 100 , and the body outlet 150 is located on a side of the upper cover 100 where the liquid inlet 130 and the liquid outlet 140 are not provided.

[0038] In this embodiment, reference Figure 6 The gaps between the multiple porous micro-pillars 210 form a steam-containing space 220 as a steam circulation space, and the steam flows in the direction 2. Figure 6 The direction indicated by the curved arrow in the figure is that the vapor formed by the evaporation phase change of the liquid working medium in the second capillary core 300 first flows into the vapor space 220, then flows into the vapor cavity 120, and finally flows from the vapor cavity 120 to the outside; the first capillary core 200 and the second capillary core 300 are the liquid working medium circulation spaces, and the liquid working medium flows in the direction 1. Figure 6In the direction indicated by the curved arrow in FIG. 1 , the liquid working medium in the liquid chamber 110 flows into the second capillary wick 300 through the first capillary wick 200 and the porous micro-columns 210 of the first capillary wick 200 under the action of capillary force.

[0039] Further, refer to Figure 4 The first capillary core 200 is square in shape, and the liquid cavity 110 is a square cavity. In the present embodiment, the length and width of the first capillary core 200 are both greater than the length and width of the liquid cavity 110 , thereby ensuring that the first capillary core 200 can completely cover the liquid cavity 110 .

[0040] Further, refer to Figure 1 and Figure 4 , multiple porous micro-pillars 210 are evenly spaced on the first capillary core 200, so that different positions of the second capillary core 300 can be supplied with liquid simultaneously through the multiple porous micro-pillars 210, so that the liquid temperatures at different positions in the second capillary core 300 are similar, thereby achieving uniform heat dissipation at different positions of the chip; when the liquid medium enters the second capillary core 300 from the left and exits from the right, the temperature of the second capillary core 300 gradually increases along the flow direction of the liquid medium, thereby causing a large temperature difference from left to right of the chip, and causing the chip to warp or break.

[0041] Specifically, in actual use, the upper cover 100, the first capillary core 200, the second capillary core 300, the lower cover 400 and the chip are arranged in sequence from top to bottom, so that liquid can be supplied to different positions of the second capillary core 300 from directly above, avoiding the problem of poor surface temperature uniformity of the microchannel phase change heat sink, thereby uniformly cooling the chip and improving the chip life and reliability.

[0042] Furthermore, the porous micro-column 210 is in a square column or a cylindrical shape.

[0043] Furthermore, the first capillary core 200 and the second capillary core 300 are integrally formed, which can reduce the heat transfer thermal resistance between the first capillary core 200 and the second capillary core 300. Specifically, the first capillary core 200 and the second capillary core 300 are integrally formed by sintering or 3D printing, wherein the sintering integrally formed includes two steps, namely, firstly sintering the first capillary core 200 and the second capillary core 300 separately by cold pressing demolding, and then performing secondary sintering to combine the two.

[0044] In this embodiment, the thickness of the first capillary wick 200 and the second capillary wick 300 can be selected as required according to the size of the heat dissipation location.

[0045] Furthermore, the average pore size of the first capillary core 200 is 10 to 50 μm, and the average pore size of the second capillary core 300 is 1 to 5 μm. Specifically, the average pore size of the first capillary core 200 is larger, which is beneficial to reducing the flow resistance of the liquid working medium. The average pore size of the second capillary core 300 is smaller, thereby forming a larger capillary force, thereby ensuring the liquid replenishment of the evaporation surface and preventing dry burning.

[0046] Further, refer to Figure 1 The lower cover 400 is provided with a first accommodating groove 410, and the first accommodating groove 410 is used to accommodate the second capillary core 300. Specifically, the setting of the first accommodating groove 410 makes the positioning of the second capillary core 300 relative to the first accommodating groove 410 more reliable.

[0047] Furthermore, the second capillary core 300 is square in shape, and the first receiving groove 410 is a square groove. In this embodiment, the length and width of the second capillary core 300 are adapted to the length and width of the first receiving groove 410, so that the second capillary core 300 can be reliably received in the first receiving groove 410.

[0048] Further, refer to Figure 2 and Figure 4 The upper cover 100 is provided with a second accommodating groove 160, and the second accommodating groove 160 is used to accommodate the first capillary core 200. Specifically, the second accommodating groove 160 is located directly below the liquid cavity 110, and the length and width of the second accommodating groove 160 are greater than the length and width of the liquid cavity 110. The first capillary core 200 is arranged in the second accommodating groove 160 to completely cover the liquid cavity 110 to form a seal.

[0049] Furthermore, the second receiving groove 160 is a square groove. In this embodiment, the length and width of the first capillary core 200 match the length and width of the second receiving groove 160 , so that the first capillary core 200 can be reliably received in the second receiving groove 160 .

[0050] Further, refer to Figure 2 and Figure 4 The upper cover 100 is provided with a third accommodating groove 170, and the third accommodating groove 170 is used to accommodate the lower cover 400. Specifically, the third accommodating groove 170 is located below the liquid chamber 110 and the vapor chamber 120, and the lower cover 400 is arranged in the third accommodating groove 170 to achieve a sealing between the lower cover 400 and the upper cover 100.

[0051] Furthermore, the lower cover 400 is square in shape, and the third receiving groove 170 is a square groove. In this embodiment, the length and width of the lower cover 400 are adapted to the length and width of the third receiving groove 170 , so that the lower cover 400 can be reliably received in the third receiving groove 170 .

[0052] Furthermore, the first capillary wick 200 and the second capillary wick 300 are both porous media prepared from metal powder.

[0053] Furthermore, the metal powder is one or more of copper powder, nickel powder and aluminum powder.

[0054] Furthermore, the lower cover 400 is made of metal material, which has good thermal conductivity, so that the heat released by the chip can be diffused to the second capillary core 300 through the lower cover 400, thereby facilitating the heat dissipation of the chip. In this embodiment, the upper cover 100 is also made of metal material.

[0055] Furthermore, the metal material is at least one of copper, aluminum, aluminum alloy and stainless steel.

[0056] In this embodiment, a high thermal conductivity thermal interface material is coated on the surface of the chip, and the side of the chip coated with the high thermal conductivity thermal interface material is in contact with the lower cover 400 .

[0057] Further, refer to Figure 1-2 The microchannel phase change heat sink and the chip are both provided with fastening screw holes 180, and screws are passed through the fastening screw holes 180 to tightly fix the microchannel phase change heat sink and the chip. In the present embodiment, the fastening screw holes 180 of the microchannel phase change heat sink are located on the upper cover 100. Furthermore, there are multiple fastening screw holes 180 on the upper cover 100, and the multiple fastening screw holes 180 are spaced around the upper cover 100. In the present embodiment, there are four fastening screw holes 180 on the upper cover 100.

[0058] refer to Figure 1-6 The coordination and action process of each mechanism of the microchannel phase change heat sink are as follows:

[0059] A high thermal conductivity thermal interface material is applied to the chip surface, and screws are passed through the fastening screw holes 180 to tightly fix the microchannel phase change heat sink and the chip. The chip generates heat when it is working, and the heat is conducted to the second capillary wick 300 through the chip shell and the lower cover 400, so that the liquid inside the second capillary wick 300 undergoes an evaporation phase change to form steam. The steam enters the steam holding space 220, and then enters the steam cavity 120 through the steam holding space 220, and then is discharged to the outside through the steam outlet 150, thereby taking away the heat of the chip and achieving heat dissipation of the chip. At the same time, the liquid working medium enters the liquid cavity 110 through the liquid inlet 130, and part of the liquid working medium moves to the second capillary wick 300 through the first capillary wick 200 and the multiple porous micro-columns 210 of the first capillary wick 200 under the synergistic effect of the capillary force and the pressure difference between the liquid cavity 110 and the steam collecting cavity 120, thereby completing the uniform liquid supply to the second capillary wick 300; the excess liquid working medium flows out to the outside through the liquid outlet 140, and finally merges into the liquid storage device together with the steam. During the entire heat dissipation process, the cold and hot working fluids belong to different flow paths, which prevents the occurrence of vapor-liquid two-phase flow, thereby preventing the instability of the vapor-liquid two-phase flow.

[0060] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent device transformations made using the contents of the present invention's specification and drawings, or direct / indirect applications in other related technical fields, under the inventive concept of the present invention are included in the patent protection scope of the present invention.

Claims

1. A microchannel phase change heat sink, characterized in that: include: The upper cover is provided with a liquid cavity and a steam cavity which are arranged at intervals, the upper cover is also provided with a liquid inlet and a liquid outlet which are communicated with the liquid cavity, and the upper cover is also provided with a steam outlet which is communicated with the steam cavity; A first capillary wick is connected to the upper cover, the upper cover is provided with a second accommodating groove, the second accommodating groove is used to accommodate the first capillary wick, the second accommodating groove is located directly below the liquid cavity, the second accommodating groove is spaced apart from the vapor cavity, and the length and width of the second accommodating groove are greater than the length and width of the liquid cavity, so as to completely cover the liquid cavity, the first capillary wick has a plurality of porous micro-pillars spaced apart at one end away from the upper cover, the gaps between the plurality of porous micro-pillars form a vapor storage space, and the vapor storage space is connected to the vapor cavity; A second capillary core is connected to the porous microcolumn, and the first capillary core and the second capillary core are both porous media; and A lower cover, which is disposed on the liquid cavity and the vapor cavity, and one end of the lower cover facing the upper cover is connected to the second capillary wick, and one end of the lower cover away from the upper cover is used for bonding the chip, and the lower cover is made of a heat-conducting material; The liquid cavity is used to accommodate a liquid working medium. The liquid working medium flows into the liquid cavity through the liquid inlet and then flows out to the outside through the liquid outlet. The liquid working medium in the liquid cavity can flow into the second capillary wick through the first capillary wick and the porous microcolumns of the first capillary wick. The chip can diffuse heat into the second capillary wick through the lower cover, so that the liquid working medium in the second capillary wick evaporates and changes phase to form steam, and then the steam enters the steam holding space and is discharged to the outside through the steam cavity and the steam outlet.

2. The microchannel phase change heat sink according to claim 1, characterized in that: A plurality of the porous micro-columns are evenly spaced and arranged on the first capillary core.

3. The microchannel phase change heat sink according to claim 1, characterized in that: The first capillary core and the second capillary core are integrally formed.

4. The microchannel phase change heat sink according to claim 1, characterized in that: The average pore size of the first capillary core is 10-50 μm, and the average pore size of the second capillary core is 1-5 μm.

5. The microchannel phase change heat sink according to claim 1, characterized in that: The porous microcolumn is in the shape of a square column or a cylinder.

6. The microchannel phase change heat sink according to claim 1, characterized in that: The lower cover is provided with a first accommodating groove, and the first accommodating groove is used for accommodating the second capillary core.

7. The microchannel phase change heat sink according to claim 1, characterized in that: The upper cover is provided with a third accommodating groove, and the third accommodating groove is used for accommodating the lower cover.

8. The microchannel phase change heat sink according to claim 1, characterized in that: The first capillary core and the second capillary core are both porous media prepared from metal powder.

9. The microchannel phase change heat sink according to claim 8, characterized in that: The metal powder is one or more of copper powder, nickel powder and aluminum powder.

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