Snowflake type fractal micro-channel radiator

Abstract

The invention discloses a snowflake type fractal micro-channel radiator, and belongs to the technical field of micro heat dissipation. The radiator is a square sheet body with a certain thickness, a radiating micro-channel is cut in the square sheet body, and the cross section of the radiating micro-channel is snowflake-shaped. A channel inlet is arranged in the middle of the square sheet body, and channel outlets are arranged on four sides. The heat dissipation channels are divided into two types: in the first type, four diagonal channels are formed by extending from channel inlets along the diagonal lines of the square sheet body; according to the second type, four vertical sideline channels are formed by vertically extending from the channel inlet to the four-side direction. In the two types of channels, the main channel generates multiple symmetric fractures to form a plurality of fractal channels which are communicated with the sideline channel. The heat dissipation micro-channels are symmetrically distributed in the square sheet body, the number of branch channels is large, heat dissipation is uniform, and the heat exchange effect is good.

Description

Technical Field

[0001] The present invention relates to the technical field of micro heat sinks, and particularly to a snowflake fractal microchannel heat sink. Background Art

[0002] With the continuous development of microscale manufacturing technology, the miniaturization of heat sinks has become an important direction for solving the heat dissipation of highly integrated electronic components. Microchannel heat sinks significantly improve the targeting of heat dissipation by precisely dissipating heat near the chip, reducing the average temperature and improving the uniformity of temperature distribution. In the prior art, a Chinese patent with the publication number CN118156232A discloses an interleaved scaled microchannel heat sink that imitates the coupling of leaf veins and honeycombs. The microchannel is provided with a fractal flow channel that imitates the coupling of leaf veins and honeycombs, and an interleaved scaled wave structure is locally arranged to cause the coolant to be shunted and converged multiple times, thereby improving the uniformity of heat dissipation in the microchannel. Its disadvantages are as follows: on the one hand, the honeycomb-shaped channels are concentrated on the outer side of the circular heat sink, while the fluid in the middle part only flows through four main channels, and there is still a large room for improving the temperature uniformity. Moreover, heat sinks with a circular structure are difficult to be applied to the heat dissipation of most square electronic components; on the other hand, although the honeycomb-shaped channels improve the flow distribution outside the heat sink, the multiple fractal processes increase the flow resistance and reduce the economy of the heat sink. Summary of the Invention

[0003] The purpose of the present invention is to provide a snowflake fractal microchannel heat sink, which can improve the temperature uniformity, reduce the flow resistance, and meet the heat dissipation requirements of square electronic components.

[0004] The technical solution adopted by the present invention: A snowflake fractal microchannel heat sink, the heat sink is a square sheet with a certain thickness, and heat dissipation microchannels are cut inside the square sheet, and the cross-section of the heat dissipation microchannels is snowflake-shaped; a channel inlet is provided in the middle of the square sheet, and channel outlets are provided on the four sides; the heat dissipation microchannels are divided into two categories: the first category extends along the diagonal of the square sheet from the channel inlet to form four diagonal channels; the second category extends perpendicular to the four sides from the channel inlet to form four vertical side channels; in the first category of channels, each diagonal channel generates multiple symmetric fractals, and the generated fractal channel I communicates with the side channels of the adjacent square sheet; in the second category of channels, each vertical side channel generates multiple symmetric fractals, and the outlets of the fractal channel II on each side communicate with the sub-vertical side channels on both sides of the vertical side channel, and the sub-vertical side channels are parallel to the vertical side channel.

[0005] As a further improvement of the present invention, after each fractal of the diagonal channel, its channel width decreases in sequence.

[0006] As a further improvement of the present invention, the included angle between the fractal channel I and the diagonal channel is 45°, and it is vertically connected to the adjacent side channel.

[0007] As a further improvement of the present invention, in the second type of channel, the included angle between the fractal channel II and the vertical side channel is 45°.

[0008] As a further improvement of the present invention, the size of the square sheet is: length × width = 8 mm × 8 mm, and the thickness is 3 mm.

[0009] Compared with the prior art, the present invention has the following technical effects:

[0010] (1) The channels in the radiator are arranged in a snowflake pattern. Starting from the channel inlet, eight main channels extend radially, namely four diagonal channels and four vertical side channels. Each main channel undergoes multiple fractals during the extension towards the side, forming multiple symmetric fractal channels. These main channels and fractal channels have up-down and left-right symmetry, thus making the flow of the coolant more uniform and sufficient, resulting in more balanced heat dissipation and better temperature uniformity.

[0011] (2) During the fractal process of the diagonal channel, the channel width gradually decreases step by step. While reducing the coolant flow rate, the flow velocity is ensured, enhancing the heat transfer capacity.

[0012] (3) Since both the diagonal channel and the vertical side channel undergo multiple fractals, forming multiple groups of symmetric fractal channels, the flow velocity of the coolant in the channel will not suddenly increase, effectively reducing the flow pressure drop and avoiding excessive loss of the coolant pumping energy. Description of the Drawings

[0013] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0014] Figure 1 is a schematic diagram of the overall structure of the snowflake fractal microchannel radiator;

[0015] Figure 2 is a schematic diagram of the structure and distribution of the cross-section of the snowflake fractal microchannel;

[0016] Figure 3 is an enlarged view of the snowflake fractal microchannel and the first type of channel;

[0017] Figure 4 is an enlarged view of the snowflake fractal microchannel and the second type of channel;

[0018] Figure 5 is a graph showing the change of the average temperature with the Reynolds number in the comparison between the snowflake fractal microchannel and the honeycomb channel;

[0019] Figure 6 It is a graph showing the variation of the temperature uniformity coefficient with the Reynolds number in the comparison between the snowflake - type fractal microchannel and the honeycomb - shaped channel;

[0020] Figure 7 It is the velocity contour map of the central cross - section in the comparison between the snowflake - type fractal microchannel and the honeycomb - shaped channel;

[0021] Figure 8 It is a graph showing the variation of the thermal resistance with the Reynolds number in the comparison between the snowflake - type fractal microchannel and the honeycomb - shaped channel;

[0022] In the figure: 1 - square sheet; 2 - heat - dissipating microchannel; 3 - channel inlet; 4 - diagonal channel; 41 - fractal channel I; 5 - vertical side - line channel; 51 - secondary vertical side - line channel; 52 - fractal channel II; 6 - channel outlet; 7 - side - line channel. Detailed implementation manners

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present invention.

[0024] As Figure 1 shown, a snowflake - type fractal microchannel heat sink is applied to chip heat dissipation and is placed above the chip. This microchannel heat sink is a square sheet 1 with a certain thickness. A heat - dissipating microchannel 2 is cut out in the square sheet 1, and the entire heat - dissipating microchannel 2 is snowflake - type, and its cross - section is as Figure 2 shown. In some embodiments, the square sheet 1 is composed of two upper and lower split sheets with the same thickness, and the heat - dissipating microchannel 2 is divided into two identical parts, which are located in the upper and lower sheets respectively, and the two split sheets are joined together to form the entire heat - dissipating microchannel 2. In other embodiments, the upper sheet has a thinner thickness, and the heat - dissipating microchannel 2 is entirely located in the lower square sheet 1. Specifically, the size of the square sheet 1 is: length × width = 8 mm × 8 mm, and the thickness is 3 mm. A channel inlet 3 is provided in the middle of the square sheet 1 as the inlet for the coolant to enter the heat - dissipating microchannel 2. Channel outlets 6 are provided on all four sides of the square sheet 1 as the outlets for the coolant to flow out. On the inner edge of the square sheet 1, a side - line channel 7 is provided, and the channel outlet 6 is located in the middle of the side - line channel 7. The snowflake - type heat - dissipating microchannel 2 is divided into two types of structures: The first type, as Figure 3 shown, extends along the diagonal of the square sheet 1 from the channel inlet 3 to form four diagonal channels 4. The second type, as Figure 4As shown, four vertical side-channel channels 5 are formed by extending perpendicularly from the channel inlet 3 in the four-side direction. In the first type of channel, each diagonal channel 4 generates multiple symmetric fractals, and the fractal channel I41 communicates with the adjacent side-channel. In the second type of channel, each vertical side-channel 5 generates multiple symmetric fractals, and the outlets of the fractal channels II52 on each side communicate with the sub-vertical side-channels 51 on both sides of the vertical side-channel 5, and the sub-vertical side-channels 51 are parallel to the vertical side-channel 5. Specifically, in the first type of channel, the fractal is generated three times, the fractal channel I41 is vertically connected to the connected side-channel, and the included angle between the fractal channel I41 and the diagonal channel 4 is 45 degrees. In the second type of channel, the fractal is generated four times, and the included angle between the fractal channel II52 and the vertical side-channel 5 is 45 degrees.

[0025] Specifically, after each fractal of the diagonal channel 4, its channel width decreases successively. In this embodiment, the diagonal channel 4 generates three fractals, starting from the channel inlet 3 and being divided into four parts, with the channel widths being 0.4 mm, 0.25 mm, 0.2 mm, and 0.15 mm in sequence. The lengths of the four parts are 2.44 mm, 0.85 mm, 0.85 mm, and 0.85 mm in sequence. The successive decrease in channel width can ensure that the flow rate does not increase significantly over a large area. Only the included angle at the fractal increases, and then it enters each fractal channel at a smaller flow rate, reducing the frictional resistance. And because the width of the diagonal channel 4 decreases, each fractal channel can ensure the uniformity of the flow distribution of the entire radiator while obtaining a smaller flow rate.

[0026] Specifically, in the second type of channel, the vertical side-channel 5 starts to fractal 0.9 mm from the center of the channel inlet 3. The channel width before fractal is 0.4 mm, the widths of the fractal channels II52 are all 0.15 mm, and the spacing between the fractal channels II52 is 0.6 mm.

[0027] In the embodiment, the height of the heat dissipation micro-channel 2 is all 0.2 mm. The channel inlet 3 is a square inlet with a side length of 0.5 mm, and the width of the channel outlet 6 is 1 mm.

[0028] The heat dissipation micro-channel of the present invention has many channel branches and uniform distribution, and has good heat absorption uniformity. From Figure 2It can be seen that the initial section of the vertical diagonal channel 4 and the vertical side channel 5 starting from the channel entrance 3 has a relatively large channel width, which can better buffer the flow rate of the coolant. And the channel width is gradually reduced, making the flow rate distribution in the 8 channels (4 diagonal channels 4 and 4 vertical side channels 5) more uniform. Therefore, the flow pressure drop can be effectively reduced, and the temperature distribution can be made more uniform. At the same time, a 45-degree fractal channel II52 is added between the three vertical side channels 5 and the secondary vertical side channel 51, which can make the flow distribution more uniform. As a secondary channel, it forms a certain degree of Dean vortices at the entrance and exit of the main flow direction of the vertical side channel and the fractal channel I51, breaking the temperature boundary layer, thereby enhancing the heat transfer effect. Dean vortices refer to the vortex phenomenon generated when the fluid flows in the pipeline due to the change of the pipeline cross-section (such as sudden expansion or contraction).

[0029] In addition, the micro radiator of the present invention is square in design, which is suitable for the heat dissipation requirements of most square electronic components and has better fitting performance in structure.

[0030] Next, relevant heat dissipation experiment simulations are carried out for the snowflake-shaped heat dissipation microchannel and the honeycomb-shaped (circular) microchannel in the background technology.

[0031]

Experiment Comparison 1

[0032] Figure 5 It is the change curve of the average temperature with the Reynolds number. The average wall temperature reflects the heat dissipation ability of the channel itself when using the same cooling medium at the same Reynolds number. It can be seen from the figure that the heat transfer ability of the present invention is significantly higher than that of the circular radiator, especially the improvement effect of the present invention is better at low inlet Reynolds numbers.

[0033]

Experiment Comparison 2

[0034] Figure 6 It is the change curve of the temperature uniformity coefficient in the two channels with the Reynolds number. Usually, in order to characterize the heat dissipation effect of the radiator, in addition to measuring the average temperature, it is also necessary to consider its temperature uniformity. If the radiator has a large temperature difference, it indicates a poor heat dissipation effect. Therefore, the smaller the temperature uniformity coefficient, the stronger the heat dissipation ability. By improving the rationality of the channel layout, the flow distribution uniformity can be improved, and thus the heat dissipation effect can be improved. It can be seen from the figure that within the studied low Reynolds number range, the temperature uniformity of the present invention is better; and the temperature uniformity coefficient shows an increasing trend with the increase of the Reynolds number.

[0035]

Experiment Comparison 3

[0036] Figure 7They are velocity cloud diagrams of the central cross-sections of two channels. The channel arrangement of the present invention is more sufficient, in which the flow distribution of the fluid is more uniform, and there is no point with a sharp temperature rise inside the channel, which brings conditions for drag reduction to the channel. Combining with the cloud diagram, it can be found that the flow velocity of the present invention is lower and more uniform. Therefore, the snowflake-shaped fractal channel layout is more reasonable and conforms to the geometric structure of the square electronic component.

[0037]

Experimental Comparison 4

[0038] Figure 8 They are comparison diagrams of the thermal resistance and flow resistance of two channels. The thermal resistance in the microchannel characterizes the resistance of the channel to heat conduction, including the resistance encountered by the heat flow from the chip to the coolant; the flow resistance characterizes the resistance of the channel to macroscopic flow. Generally, by increasing the number of channels, the uniformity of the flow distribution can be improved, thereby improving the heat dissipation effect, but this usually inevitably leads to the destruction of the flow boundary layer and increases the flow loss. Due to the drag reduction design of changing the cross-sectional area of the fractal channel and adding secondary flow channels in the present invention, it can be seen from the figure that it not only has lower thermal resistance, that is, better heat exchange ability, but also reduces the pressure drop at different inlet Reynolds numbers.

[0039] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. All changes that can be made within the knowledge of those skilled in the art without departing from the purpose of the present invention are within the protection scope of the claims of the present invention.

Claims

1. A snowflake fractal microchannel radiator, characterized in that: The heat sink is a square sheet (1) with a certain thickness, and a heat dissipation microchannel (2) is cut out inside the square sheet (1), and the cross section of the heat dissipation microchannel (2) is snowflake-shaped; a channel inlet (3) is provided in the middle of the square sheet (1), and channel outlets (6) are provided on four sides; the heat dissipation microchannels (2) are divided into two categories: the first category extends from the channel inlet (3) along the diagonal of the square sheet (1) to form four diagonal channels (4); the second category extends from the channel inlet (3) perpendicular to the four sides to form a diagonal channel (5); Four vertical sideline channels (5) are formed; in the first type of channels, each of the diagonal channels (4) generates multiple symmetrical fractals, and the generated fractal channel I (41) is connected to the sideline channel (6) of the adjacent square sheet (1); in the second type of channels, each of the vertical sideline channels (4) generates multiple symmetrical fractals, and the outlet of the fractal channel II (52) on each side is connected to the secondary vertical sideline channels (51) on both sides of the vertical sideline channel (5), and the secondary vertical sideline channels (51) are parallel to the vertical sideline channels (5).

2. The snowflake fractal microchannel heat sink according to claim 1, characterized in that: The width of the diagonal channel (4) decreases successively after each fractal.

3. The snowflake fractal microchannel heat sink according to claim 1, characterized in that: In the first type of channels, the angle between the fractal channel I (41) and the diagonal channel (4) is 45°, and the fractal channel I (41) is vertically connected to the adjacent side channel (6).

4. The snowflake fractal microchannel heat sink according to claim 1, characterized in that: In the second type of channel, the angle between the fractal channel II (52) and the vertical edge channel (5) is 45°.

5. The snowflake fractal microchannel heat sink according to claim 1, characterized in that: The dimensions of the square sheet (1) are: length x width = 8 mm x 8 mm, and the thickness is 3 mm.

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