A non-homogeneous microchannel micro radiator under ultra-high heat flux

Abstract

The invention relates to the technical field of heat sinks for microelectronic devices, and discloses a non-homogeneous microchannel micro heat sink under ultra-high heat flux, comprising a substrate, on which a plurality of heat dissipation channels for the circulation of working fluid are provided; the heat dissipation channel comprises a first stage and a second stage which are connected; the first stage is composed of a plurality of first grooves which are connected in sequence, the width of the middle section of the first groove is greater than the width of the openings on both sides and is in an expansion and contraction shape, and a plurality of pits are provided on the bottom surface of the first groove; the second stage is composed of a plurality of second grooves which are connected in sequence, the width of the middle section of the second groove is greater than the width of the openings on both sides and is in an expansion and contraction shape, and a plurality of pin fins are fixedly connected to the bottom surface of the second groove. The invention reduces the excess temperature at the boiling starting point, improves the boiling stability, improves the heat transfer coefficient, reduces the wall temperature, improves the surface wettability, generates a better annular flow, and improves the convective boiling heat transfer coefficient and the temperature uniformity characteristic.

Description

Technical Field

[0001] The invention relates to the technical field of microelectronic device heat sinks, and in particular to a non-homogeneous microchannel micro heat sink under ultra-high heat flux. Background Art

[0002] Heat dissipation technology in high-temperature environments is still an unresolved problem. With the miniaturization and increased integration of electronic devices, the requirements for heat dissipation technology are becoming increasingly higher. Therefore, the design of heterogeneous microchannel structures under ultra-high heat flux has important practical application value. In the current field of microchannel design, a common method is to increase the heat exchange capacity by reducing the flow channel cross-section, while enhancing the heat dissipation effect by matching the coolant flow rate. However, with the further reduction of the microchannel and the increase in flow rate, the bottleneck problem of heat dissipation performance gradually emerges, and the heat dissipation problem in high-temperature environments has become more complicated, because the thermal expansion and heat conduction problems of materials in high-temperature environments will affect the heat dissipation effect. Summary of the invention

[0003] The object of the present invention is to provide a non-homogeneous microchannel micro heat sink under ultra-high heat flux, aiming to solve or improve at least one of the above-mentioned technical problems.

[0004] To achieve the above object, the present invention provides the following solution: The present invention provides a non-homogeneous microchannel micro heat sink under ultra-high heat flux, comprising a substrate, on which a plurality of heat dissipation channels for the flow of working fluid are opened;

[0005] The heat dissipation channel includes a first stage and a second stage that are connected;

[0006] The first stage is composed of a plurality of first grooves connected in sequence, the width of the middle section of the first groove is greater than the width of the openings on both sides and is in an expanding and contracting shape, and a plurality of pits are formed on the bottom surface of the first groove;

[0007] The second stage is composed of a plurality of second grooves connected in sequence, the width of the middle section of the second groove is greater than the width of the openings on both sides and is in an expansion and contraction shape, and a plurality of needle ribs are fixedly connected to the bottom surface of the second groove;

[0008] The second groove has the same size as the first groove.

[0009] Optionally, the sizes of the plurality of pits in the first groove decrease layer by layer from the center of the first groove to the outside.

[0010] Optionally, the first groove and the second groove are both regular hexagons.

[0011] Optionally, the bottom surface of the first groove, the surface of the pit, the bottom surface of the second groove, and the surface of the needle fin are all covered with a nano coating.

[0012] Optionally, the nanocoating consists of a plurality of nanowires.

[0013] Optionally, the diameter of some of the nanowires in the nanocoating is 20-200 nm, the density is 10-200 um, and the height is 5-15 um.

[0014] Optionally, the diameter of the plurality of pits in the first groove is 20-200 nm, the density is 10-200 um, and the height is 5-15 um.

[0015] Optionally, the diameter of the plurality of needle ribs in the second groove is 1-10 um, the spacing is 0.2-10 um, and the height is 2-10 um.

[0016] Optionally, the length of the first groove is 50-200 um, the height is 20-50 um, and the width expansion / contraction ratio between the middle section of the first groove and the two openings is 0.3-0.7.

[0017] Optionally, the substrate is silicon.

[0018] The present invention discloses the following technical effects:

[0019] By setting the first groove and the second groove in an expanding and contracting shape with a middle section width greater than the width of the openings on both sides to form a periodic expansion and contraction structure, the reflux resistance of the gas is increased and the backflow is simulated, so as to improve the stability of boiling; at the same time, the liquid film is disturbed, the evaporation heat transfer of the liquid film is promoted, the heat transfer coefficient is improved, and the wall temperature is reduced; the top of the expansion and contraction structure is easy to store liquid, which delays the occurrence of local drying, reduces the maximum wall temperature, and improves the uniformity of temperature distribution.

[0020] By arranging a plurality of pits in the first groove, it is beneficial to reduce the excess temperature at the beginning of boiling. The super-hydrophilic surface at the front end of the microchannel promotes the detachment of bubbles, improves the nucleate boiling heat transfer, and improves the hydrophobicity. A plurality of needle ribs are arranged in the second groove. The needle ribs have a capillary effect, which simulates the occurrence of local drying up at the tail, improves the uniformity of temperature distribution, and improves hydrophilicity, so that the first stage and the second stage are coordinated to achieve the coupling of non-uniform wettability and non-uniform composite microstructure, improve surface wettability, produce better annular flow, and improve the convective boiling heat transfer coefficient and uniform temperature characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0022] Figure 1 It is a schematic diagram of the overall three-dimensional structure of the present invention;

[0023] Figure 2 It is a schematic diagram of the three-dimensional structure of the first groove and the second groove of the present invention;

[0024] Figure 3 is a cross-sectional view of a first groove of the present invention;

[0025] Figure 4 It is a cross-sectional view of the second groove of the present invention.

[0026] In the figure: 1, substrate; 2, heat dissipation channel; 21, first stage; 211, first groove; 212, pit; 22, second stage; 221, second groove; 222, needle fin. DETAILED DESCRIPTION

[0027] 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.

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] Reference Figure 1-Figure 4 The present invention provides a non-homogeneous microchannel micro heat sink under ultra-high heat flux, comprising a substrate 1, on which a plurality of heat dissipation channels 2 for the flow of working fluid are opened;

[0030] The heat dissipation channel 2 includes a first stage 21 and a second stage 22 which are connected;

[0031] The first stage 21 is composed of a plurality of first grooves 211 connected in sequence. The width of the middle section of the first groove 211 is greater than the width of the openings on both sides and is in an expanding and contracting shape. A plurality of pits 212 are formed on the bottom surface of the first groove 211.

[0032] The second stage 22 is composed of a plurality of second grooves 221 connected in sequence, the width of the middle section of the second groove 221 is greater than the width of the openings on both sides, and is in an expanding and contracting shape, and the bottom surface of the second groove 221 is fixedly connected with a plurality of pin ribs 222;

[0033] The second groove 221 has the same size as the first groove 211 .

[0034] By setting the first groove 211 and the second groove 221 in the middle section with a width greater than the width of the openings on both sides in an expanding and contracting shape to form a periodic expansion and contraction structure, the gas reflux resistance is increased and the counterflow is simulated, which is used to improve the boiling stability; at the same time, the liquid film is disturbed, the liquid film evaporation heat transfer is promoted, the heat transfer coefficient is improved, and the wall temperature is reduced; the top of the expansion and contraction structure is easy to store liquid, which delays the occurrence of local drying, reduces the maximum wall temperature, and improves the uniformity of temperature distribution;

[0035] By arranging a plurality of pits 212 in the first groove 211, it is beneficial to reduce the excess temperature at the beginning of boiling. The super-hydrophilic surface at the front end of the microchannel promotes the detachment of bubbles, improves the nucleate boiling heat transfer, and improves the hydrophobicity. A plurality of needle fins 222 are arranged in the second groove 221. The needle fins 222 have a capillary effect, which simulates the occurrence of local drying up at the tail, improves the uniformity of temperature distribution, and improves hydrophilicity. Therefore, the first stage 21 and the second stage 22 cooperate to achieve the coupling of non-uniform wettability and non-uniform composite microstructure, improve surface wettability, produce better annular flow, and improve the convective boiling heat transfer coefficient and uniform temperature characteristics.

[0036] It should be noted that the heterogeneous effect refers to the difference in physical properties between different regions in the same material, such as thermal expansion coefficient, thermal conductivity, etc. The present invention reasonably utilizes these differences through the structure of the first groove 211 and the second groove 221, thereby effectively improving the heat dissipation performance.

[0037] According to a further optimization scheme, the sizes of the plurality of pits 212 in the first groove 211 decrease layer by layer from the center of the first groove 211 to the outside, thereby improving the nucleate boiling heat transfer in the first stage 21 .

[0038] Furthermore, the sizes of the plurality of needle fins 222 in the second groove 221 decrease layer by layer from the center of the second groove 221 to the outside.

[0039] According to a further optimization scheme, the first groove 211 and the second groove 221 are both regular hexagons or circles.

[0040] According to a further optimized solution, the bottom surface of the first groove 211 , the surface of the pit 212 , the bottom surface of the second groove 221 , and the surface of the needle fin 222 are all covered with a nano coating, and the nano coating is composed of a plurality of nanowires.

[0041] The nano-coating plays a reinforcing role and can meet the requirements of multi-scale and wall wettability of the vaporization core during bubble nucleation, intense evaporation of the three-phase contact line and rewetting to local drying out in the process of ultra-high heat flux microchannel flow boiling on a spatial scale, thereby achieving efficient, stable and uniform heat dissipation.

[0042] According to further optimization scheme, the diameter of several nanowires in the nanocoating is 20-200nm, the density is 10-200um, and the height is 5-15um.

[0043] According to a further optimization scheme, the diameter of the plurality of pits 212 in the first groove 211 is 20-200 nm, the density is 10-200 um, and the height is 5-15 um.

[0044] According to a further optimized solution, the diameter of the plurality of needle ribs 222 in the second groove 221 is 1-10 um, the spacing is 0.2-10 um, and the height is 2-10 um.

[0045] According to a further optimization scheme, the length of the first groove 211 is 50-200 um, the height is 20-50 um, and the width expansion ratio between the middle section of the first groove 211 and the two openings is 0.3-0.7.

[0046] In a further optimized solution, the substrate 1 is silicon.

[0047] The heat flux of common microchannels in existing microelectronic device heat sinks is less than 100W / cm 2 The heat dissipation channel 2 of the present invention is 500W / cm 2 .

[0048] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0049] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A non-homogeneous microchannel micro heat sink under ultra-high heat flux, characterized in that: It comprises a substrate (1), on which a plurality of heat dissipation channels (2) for the circulation of working fluid are provided; The heat dissipation channel (2) comprises a first stage (21) and a second stage (22) which are connected to each other; The first stage (21) is composed of a plurality of first grooves (211) connected in sequence, the width of the middle section of the first groove (211) is greater than the width of the openings on both sides and is in an expanding and contracting shape, and a plurality of pits (212) are provided on the bottom surface of the first groove (211); The second stage (22) is composed of a plurality of second grooves (221) connected in sequence, the width of the middle section of the second groove (221) is greater than the width of the openings on both sides and is in an expanding and contracting shape, and a plurality of needle ribs (222) are fixedly connected to the bottom surface of the second groove (221); The second groove (221) has the same size as the first groove (211); The sizes of the plurality of pits (212) in the first groove (211) decrease layer by layer from the center of the first groove (211) toward the outside.

2. The ultra-high heat flux heterogeneous microchannel micro heat sink according to claim 1, characterized in that: The first groove (211) and the second groove (221) are both regular hexagons.

3. The ultra-high heat flux heterogeneous microchannel micro heat sink according to claim 1, characterized in that: The bottom surface of the first groove (211), the surface of the pit (212), the bottom surface of the second groove (221), and the surface of the needle fin (222) are all covered with a nano coating.

4. The non-homogeneous microchannel micro heat sink under ultra-high heat flux according to claim 3, characterized in that: The nano coating is composed of a plurality of nanowires.

5. The ultra-high heat flux heterogeneous microchannel micro heat sink according to claim 4, characterized in that: The diameter of the nanowires in the nanocoating is 20-200 nm, the density is 10-200 um, and the height is 5-15 um.

6. The ultra-high heat flux heterogeneous microchannel micro heat sink according to claim 1, characterized in that: The diameter of the plurality of pits (212) in the first groove (211) is 20-200 nm, the density is 10-200 um, and the height is 5-15 um.

7. The ultra-high heat flux heterogeneous microchannel micro heat sink according to claim 1, characterized in that: The plurality of needle ribs (222) in the second groove (221) have a diameter of 1-10 um, a spacing of 0.2-10 um, and a height of 2-10 um.

8. The ultra-high heat flux heterogeneous microchannel micro heat sink according to claim 1, characterized in that: The length of the first groove (211) is 50-200 um, the height is 20-50 um, and the width expansion-contraction ratio between the middle section and the two openings of the first groove (211) is 0.3-0.

7.

9. The ultra-high heat flux heterogeneous microchannel micro heat sink according to claim 1, characterized in that: The substrate (1) is silicon.

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