Bidirectional reverse flow type structure micro-channel radiator

Abstract

The invention discloses a bidirectional reverse flow type structure micro-channel radiator, which comprises a first substrate, a second substrate and a cover plate which are sequentially stacked from bottom to top, two first micro-channels are arranged on the first substrate, a plurality of concave cavities and a plurality of convex ribs are arranged on two side surfaces of each first micro-channel, and cooling liquid outlets are formed in two ends of each first micro-channel; a first cooling liquid inlet and a second cooling liquid inlet are formed in the two sides of the second substrate, two sets of second micro-channels are arranged in the middle of the second substrate, one set of second micro-channels are communicated with the first cooling liquid inlet, the other set of second micro-channels are communicated with the second cooling liquid inlet, drainage pipes are arranged at the tail ends of the second micro-channels, and the positions of the drainage pipes correspond to those of the first micro-channels. And the flowing directions of cooling liquid in the two groups of second micro-channels are opposite. According to the invention, through the arrangement of the bidirectional countercurrent micro-channel, a heat exchange dead zone caused by too small temperature difference at the tail end of a traditional downstream micro-channel is avoided, the surface heat dissipation uniformity of the whole radiator is improved, the surface temperature gradient of a to-be-cooled device is reduced, and the heat dissipation efficiency is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of microchannel radiators, in particular to a bidirectional counter-flow structure microchannel radiator. Background Art

[0002] With the profound evolution of information technology, electronic devices such as smartphones and 5G base stations, built around semiconductor devices, microelectronic chips, and integrated circuits, have become critical infrastructure supporting the development of modern society. Against this backdrop, thermal management technology, a key component in ensuring the efficient operation of electronic devices and driving the development of new devices, is facing increasingly severe challenges.

[0003] Compared to traditional cooling methods, microchannel cooling technology has become a research hotspot of common interest in academia and industry due to its high area heat flux density, strong heat transfer capability, and miniaturized integration advantages. Since Tuckerman's team proposed the concept of microchannel heat sinks in 1981, the technology has undergone iterative upgrades from basic cold plate structures to chip-embedded designs. Currently, the commonly used downstream microchannels use parallel straight channels or simple serpentine flow channel designs, with the cooling medium and high-temperature fluid flowing in the same direction, and the channel cross-section is mostly rectangular or circular.

[0004] However, the high flow resistance of the fluid in the microchannel causes the cooling fluid to continuously accumulate temperature along the flow path, leading to uneven temperature distribution on the surface of the cooled device and significant temperature gradients in localized areas. This thermal non-uniformity not only creates high-temperature hotspots, threatening device operational stability, but can also cause structural deformation due to concentrated thermal stress, severely reducing system reliability. Summary of the Invention

[0005] Purpose of the invention: To address the shortcomings of existing microchannel radiators, such as continuous temperature accumulation along the process, which causes uneven temperature distribution on the surface of the cooled device and the formation of significant temperature gradients in local areas, the present invention proposes a bidirectional countercurrent structure microchannel radiator to improve the uniformity of heat dissipation on the entire radiator surface and reduce the temperature gradient on the radiator surface.

[0006] Technical solution: To solve the above problems, the present invention adopts a bidirectional counter-flow structure microchannel radiator, comprising a first substrate, a second substrate and a cover plate stacked in sequence from bottom to top, wherein the first substrate is provided with two first microchannels, and the two side surfaces of the first microchannel are provided with a plurality of concave cavities and a plurality of convex ribs, wherein the concave cavities are formed by the first substrate plate surface being recessed away from the middle of the first microchannel, and the convex ribs are formed by the first substrate plate surface being protruded toward the middle of the first microchannel, and coolant outlets are provided at both ends of the first microchannel;

[0007] Cooling liquid inlet 1 and cooling liquid inlet 2 are provided on both sides of the second substrate, and two groups of second microchannels are provided in the middle of the second substrate, each group includes a plurality of second microchannels arranged in parallel, one group of second microchannels is connected to cooling liquid inlet 1, and the other group of second microchannels is connected to cooling liquid inlet 2. A drainage tube is provided at the tail end of the second microchannel, and the position of the drainage tube corresponds to that of the first microchannel. The coolant flows in the two groups of second microchannels in opposite directions.

[0008] Furthermore, the concave cavity and the convex rib are respectively arranged on two different side surfaces of the first microchannel and are staggered along the axis direction of the first microchannel.

[0009] Furthermore, the concave cavity and the convex rib have the same shape, and the cross-section of the concave cavity and the convex rib is one of rectangular, triangular, and arc-shaped.

[0010] Furthermore, the concave cavities and the convex ribs are arranged at equal intervals, and the interval between the concave cavities and adjacent convex ribs along the axis of the first microchannel is 1.5 to 2 mm.

[0011] Furthermore, the second microchannel has a width of 0.5 to 0.6 mm, a length of 25 to 30 mm, a height of 2 to 3 mm, and a distance between two adjacent second microchannels of 0.6 to 0.8 mm.

[0012] Furthermore, the cross section of the drainage tube is circular.

[0013] Furthermore, the diameter of the drainage tube is 0.8 to 1 mm.

[0014] Furthermore, the axial direction of the first microchannel is perpendicular to the axial direction of the second microchannel.

[0015] Furthermore, the first coolant inlet is connected to inlet pipe one, and the second coolant inlet is connected to inlet pipe two; coolant outlet one and coolant outlet two are provided at both ends of the first microchannel, the first coolant outlet is connected to outlet pipe one, and the second coolant outlet is connected to outlet pipe two.

[0016] Furthermore, the outer diameters of the inlet pipe 1 and the inlet pipe 2 are 1.5-2.5 mm, and the wall thickness is 0.5-0.8 mm; the outer diameters of the outlet pipe 1 and the outlet pipe are 3.5-4.5 mm, and the wall thickness is 0.5-0.8 mm.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) by arranging bidirectional countercurrent microchannels, the heat exchange dead zone caused by the small temperature difference at the end of the traditional downstream microchannel is avoided, the heat dissipation uniformity of the entire radiator surface is improved, the surface temperature gradient of the device to be cooled is reduced, and the heat dissipation efficiency is effectively improved; (2) when the drainage pipe is used for drainage, the fluid flow rate is increased, secondary heat dissipation is formed, and the heat dissipation efficiency is further improved; (3) a staggered concave cavity and convex rib structure is arranged in the first microchannel, which significantly enhances the heat exchange efficiency between the fluid and the wall by periodically inducing eddy separation, enhancing secondary flow and expanding the heat transfer surface area, and at the same time breaks the laminar boundary layer to increase the local turbulence intensity, so that the heat transfer coefficient is multiplied. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the overall structure of the bidirectional counter-flow microchannel radiator of the present invention;

[0019] Figure 2 This is an exploded view of the structure of the bidirectional counter-flow microchannel radiator of the present invention;

[0020] Figure 3 This is a schematic structural diagram of the first substrate of the present invention;

[0021] Figure 4 This is an enlarged schematic diagram of the first microchannel structure of the present invention;

[0022] Figure 5 Schematic diagram of the second substrate structure of the present invention;

[0023] Figure 6 This is an enlarged schematic diagram of the second microchannel structure of the present invention;

[0024] Figure 7 This is a schematic diagram of the working state of the bidirectional counter-flow structure microchannel radiator of the present invention;

[0025] Figure 8 This is the temperature distribution diagram of the traditional downstream radiator heat dissipation simulation experiment;

[0026] Figure 9 This is the temperature distribution diagram of the heat dissipation simulation experiment of the radiator of the present invention. DETAILED DESCRIPTION

[0027] like Figure 1 and Figure 2 As shown, a bidirectional counter-flow structure microchannel heat sink in this embodiment includes a first substrate 1, a second substrate 2 and a cover plate 3 stacked in sequence from bottom to top.

[0028] like Figure 3 and Figure 4As shown, two first microchannels 1-3 are symmetrically arranged in the middle of the first substrate 1. The first microchannel 1-3 is rectangular in shape and its bottom does not penetrate the first substrate 1. Multiple cavities 1-1 and ribs 1-2 are provided on both sides of the first microchannel 1-3. The cavities 1-1 are formed by the first substrate 1 being recessed away from the middle of the first microchannel 1-3, and the ribs 1-2 are formed by the first substrate 1 being raised toward the middle of the first microchannel 1-3. The cavities 1-1 and ribs 1-2 are equidistantly arranged on two different sides of the first microchannel 1-3 and staggered along the axis of the first microchannel 1-3. The spacing between the cavities 1-1 and adjacent ribs 1-2 along the axis of the first microchannel 1-3 is 1.5 to 2 mm. The cavities 1-1 and ribs 1-2 have the same shape, and their cross-sections are rectangular, triangular, or arc-shaped. In this embodiment, they are rectangular.

[0029] The first microchannel 1-3 is provided with a coolant outlet 1 6 and a coolant outlet 2 7 at both ends. The coolant outlet 1 6 is connected to an outlet pipe 1 6-1, and the coolant outlet 2 7 is connected to an outlet pipe 2 7-1. The outer diameters of the outlet pipe 1 6-1 and the outlet pipe 7-1 are 3.5 to 4.5 mm, and the wall thickness is 0.5 to 0.8 mm.

[0030] like Figure 5 and Figure 6 As shown, two groups of second microchannels 2-2 are symmetrically arranged in the middle of the second substrate 2. Each group includes several parallel second microchannels 2-2. The second microchannels 2-2 are axially perpendicular to the first microchannels 1-3 and extend through the second substrate 2 from top to bottom. The second microchannels 2-2 have a width of 0.5-0.6 mm, a length of 25-30 mm, and a height of 2-3 mm. The spacing between two adjacent second microchannels 2-2 in each group is 0.6-0.8 mm. The end of the two groups of second microchannels 2-2 that is closest to each other is the tail end. Drainage tubes 2-1 are located at the tail end of the second microchannels 2-2. The position of drainage tubes 2-1 corresponds to that of the first microchannels 1-3. The cross-section of drainage tubes 2-1 is circular with a diameter of 0.8-1 mm. The diameter of drainage tubes 2-1 is larger than the width of the second microchannels 2-2. When fluid flows from the second microchannels 2-2 into drainage tubes 2-1, it can effectively reduce the pressure drop of the fluid flow and reduce energy loss.

[0031] Coolant inlet 1 4 and coolant inlet 2 5 are provided on both sides of the second substrate 2. One set of second microchannels 2-2 communicates with coolant inlet 1 4, while the other set of second microchannels 2-2 communicates with coolant inlet 2 5. Coolant inlet 1 4 is connected to inlet pipe 1 4-1, while coolant inlet 2 5 is connected to inlet pipe 2 5-1. Both inlet pipes 1 4-1 and 2 5-1 have outer diameters of 1.5-2.5 mm and wall thicknesses of 0.5-0.8 mm.

[0032] The working principle of the present invention is as follows: Figure 7 As shown, the heat sink of the present invention is placed on the device to be cooled, and coolant is injected from inlet pipe 1 4-1 and inlet pipe 2 5-1. The coolant flows into the two groups of second microchannels 2-2 from coolant inlet 1 4 and coolant inlet 2 5 on both sides of the second substrate 2. The flow directions of the coolant in the two groups of second microchannels 2-2 are opposite, and the coolant is dissipated from the device to be cooled by the flow of the coolant in the second microchannels 2-2. The coolant flows in from both ends and out from the middle, avoiding the heat exchange dead zone caused by the small temperature difference at the end of the traditional downstream microchannel, and effectively improving the heat dissipation efficiency. The coolant flows through the second microchannel 2-2 and flows to the drainage pipe 2-1 at the tail end, and flows into the first microchannel 1-3 through the drainage pipe 2-1. During this process, the coolant flow area is reduced and the flow rate is increased, forming secondary heat dissipation and improving the heat dissipation efficiency.

[0033] As the coolant flows through first microchannel 1-3, it separates from the wall due to the sudden expansion effect as it passes through cavity 1-1, forming a recirculation vortex within cavity 1-1. Flow obstruction at the trailing edge of rib 1-2 creates a Karman vortex street. These two interactions form periodic induced vortex separation. Simultaneously, as the fluid flows through rib 1-2, the flow cross-section suddenly decreases, causing the flow velocity to accelerate locally. This results in increased pressure in front of rib 1-2 and decreased pressure behind it. This separation creates a low-pressure recirculation zone in cavity 1-1, creating a lateral pressure difference with the low-pressure zone behind rib 1-2, thereby enhancing secondary flow. Furthermore, the geometric undulations of cavity 1-1 and rib 1-2 directly increase the fluid contact area, expanding the heat transfer area and further improving heat dissipation efficiency. After flowing through first microchannel 1-3, the coolant exits through coolant outlet 1 (6) and coolant outlet 2 (7).

[0034] In order to verify the performance of the microchannel radiator provided by the present invention in solving the hot spot problem, the two microchannel radiators were simulated and compared using ANSYS-Fluent software, taking the traditional downstream microchannel heat dissipation as a reference.

[0035] The thermal simulation model parameters and boundary conditions are set as follows: the coolant is deionized water, and the coolant temperature is 25° C. The second microchannel is 3 mm high and 0.6 mm wide.

[0036] The turbulence model is k-epsilon (2eqn) and Realizabe model, the wall function is scalable wall function (SWF), and the radiator is made of aluminum alloy.

[0037] The inlet flow rate of the bidirectional counter-flow microchannel radiator of the present invention and the conventional downstream microchannel radiator is set at 0.6 m / s. Except for the heat source surface, all other surfaces are thermally insulated. The central heat source area is 40 mm x 40 mm in size and has a heat flux of 100,000 W / m 2 .

[0038] The same viscosity model and solution method are used for the two microchannel radiators to obtain Figure 8 、 9 The results are shown. Figure 8 It can be seen that under the traditional downstream heat dissipation structure, the highest temperature of the heat source is 67.98℃, the lowest is 45.89℃, and the maximum temperature difference of the heat source is 22.09℃. Figure 9 It can be seen that under the bidirectional counter-flow microchannel heat dissipation structure, the highest temperature of the heat source is 55.76°C and the lowest is 43.46°C, and the maximum temperature difference of the heat source is 12.24°C; therefore, compared with the traditional downstream heat dissipation structure, the double-layer counter-flow composite microchannel heat dissipation structure has better heat dissipation capacity and better cooling surface temperature uniformity.

[0039] In summary, the present invention divides the traditional downstream channel into two sections, and realizes the arrangement of bidirectional countercurrent microchannels by setting up two groups of second microchannels with opposite coolant flow directions, thereby avoiding the heat exchange dead zone caused by the small temperature difference at the end of the traditional downstream microchannel, and effectively improving the heat dissipation efficiency. The coolant in the second microchannel is led to the first microchannel through the drainage pipe, and the fluids in multiple microchannels are converged into two channels, increasing the flow rate, forming secondary heat dissipation, and improving the heat dissipation efficiency. A staggered concave cavity and convex rib structure is set in the first microchannel, which significantly enhances the heat exchange efficiency between the fluid and the wall by periodically inducing eddy separation, enhancing secondary flow and expanding the heat transfer surface area, while breaking the laminar boundary layer to increase the local turbulence intensity and multiplying the heat transfer coefficient. The present invention reconstructs the flow field distribution, effectively reduces the surface temperature gradient of the cooled device, suppresses local hot spots and reduces thermal stress, and exhibits the dual advantages of high heat dissipation density and temperature uniformity in the fields of chip heat dissipation, power battery thermal management and high-energy laser cooling.

Claims

1. A bidirectional counter-flow structure microchannel radiator, characterized in that: The invention comprises a first substrate (1), a second substrate (2) and a cover plate (3) stacked in sequence from bottom to top, wherein the first substrate (1) is provided with two first microchannels (1-3), and the two side surfaces of the first microchannel (1-3) are provided with a plurality of concave cavities (1-1) and a plurality of convex ribs (1-2), wherein the concave cavities (1-1) are formed by the first substrate (1) being concave in a direction away from the middle of the first microchannel (1-3), and the convex ribs (1-2) are formed by the first substrate (1) being convex in a direction close to the middle of the first microchannel (1-3), and cooling liquid outlets are provided at both ends of the first microchannel (1-3); A cooling liquid inlet 1 (4) and a cooling liquid inlet 2 (5) are provided on both sides of the second substrate (2); two groups of second microchannels (2-2) are provided in the middle of the second substrate (2); each group includes a plurality of second microchannels (2-2) arranged in parallel; one group of the second microchannels (2-2) is connected to the cooling liquid inlet 1 (4); and the other group of the second microchannels (2-2) is connected to the cooling liquid inlet 2 (5); a drainage tube (2-1) is provided at the tail end of the second microchannel (2-2); the position of the drainage tube (2-1) corresponds to that of the first microchannel (1-3); and the cooling liquid flows in opposite directions in the two groups of the second microchannels (2-2).

2. The bidirectional counter-flow structure microchannel radiator according to claim 1, characterized in that: The concave cavity (1-1) and the convex rib (1-2) are respectively arranged on two different side surfaces of the first microchannel (1-3), and are staggered along the axial direction of the first microchannel (1-3).

3. The bidirectional counter-flow structure microchannel radiator according to claim 2, characterized in that: The concave cavity (1-1) and the convex rib (1-2) have the same shape, and the cross sections of the concave cavity (1-1) and the convex rib (1-2) are one of rectangular, triangular and circular arc shapes.

4. The bidirectional counter-flow structure microchannel radiator according to claim 3, characterized in that: The concave cavity (1-1) and the convex rib (1-2) are arranged at equal intervals, and the interval between the concave cavity (1-1) and the adjacent convex rib (1-2) along the axis direction of the first microchannel (1-3) is 1.5 to 2 mm.

5. The bidirectional counter-flow structure microchannel radiator according to claim 1, characterized in that: The second microchannel (2-2) has a width of 0.5-0.6 mm, a length of 25-30 mm, a height of 2-3 mm, and a distance between two adjacent second microchannels (2-2) of 0.6-0.8 mm.

6. The bidirectional counter-flow structure microchannel radiator according to claim 1, characterized in that: The drainage tube (2-1) has a circular cross section.

7. The bidirectional counter-flow structure microchannel radiator according to claim 6, characterized in that: The diameter of the drainage tube (2-1) is 0.8-1 mm.

8. The bidirectional counter-flow structure microchannel radiator according to claim 1, characterized in that: The axial direction of the first microchannel (1-3) is perpendicular to the axial direction of the second microchannel (2-2).

9. The bidirectional counter-flow structure microchannel radiator according to claim 1, characterized in that: The cooling liquid inlet 1 (4) is connected to an inlet pipe 1 (4-1), and the cooling liquid inlet 2 (5) is connected to an inlet pipe 2 (5-1); a cooling liquid outlet 1 (6) and a cooling liquid outlet 2 (7) are provided at both ends of the first microchannel (1-3), the cooling liquid outlet 1 (6) is connected to an outlet pipe 1 (6-1), and the cooling liquid outlet 2 (7) is connected to an outlet pipe 2 (7-1).

10. The bidirectional counter-flow structure microchannel radiator according to claim 9, characterized in that: The outer diameters of the inlet pipe 1 (4-1) and the inlet pipe 2 (5-1) are 1.5-2.5 mm, and the wall thickness is 0.5-0.8 mm; the outer diameters of the outlet pipe 1 (6-1) and the outlet pipe (7-1) are 3.5-4.5 mm, and the wall thickness is 0.5-0.8 mm.

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