CN215683061U

CN215683061U - Enhanced heat dissipation device using array heat dissipation fins

Info

Publication number: CN215683061U
Application number: CN202121922140.6U
Authority: CN
Inventors: 孙川; 周群; 许立程
Original assignee: Zhuhai Glick Technology Co ltd
Current assignee: Zhuhai Glick Technology Co ltd
Priority date: 2021-08-17
Filing date: 2021-08-17
Publication date: 2022-01-28
Anticipated expiration: 2031-08-17

Abstract

The utility model discloses a reinforced heat dissipation device using array heat dissipation fins, and relates to the technical field of heat dissipation of electronic components. A fin substrate of the heat dissipation device and the cover plate enclose a hollow cavity with two open ends, one end of the hollow cavity is connected with the cooling medium supply device, and the other end of the hollow cavity is connected with the cooling medium recovery device; the radiating fins are trapezoidal or triangular, are positioned at the top of the fin substrate and are distributed in the hollow cavity; the radiating fins perpendicular to the flowing direction of the cooling medium are uniformly distributed at equal intervals, the radiating fins parallel to the flowing direction of the cooling medium are uniformly distributed at equal intervals, and the adjacent radiating fins are centrosymmetric. The main channel and the secondary channel are arranged in the radiating fin, and the secondary channel and the flow direction of the cooling medium form two complementary angles, so that the secondary flow periodically breaks away from the main flow and then flows into the main flow, the heat convection coefficient is high, and the temperature distribution of a heat source is uniform; the area of the flow cross section is increased, the flow velocity of the main flow is reduced, and the pressure drop is reduced.

Description

Enhanced heat dissipation device using array heat dissipation fins

Technical Field

The utility model relates to the technical field of heat dissipation of electronic components, in particular to an enhanced heat dissipation device using array heat dissipation fins.

Background

The method for enhancing the convection heat transfer mainly comprises the following steps: the heat exchange area is increased, the flow speed is increased, phase change is introduced, secondary flow generated by disturbance is increased, the thermophysical property of the fluid is improved, and the like. In particular, in heat exchange occasions such as heat dissipation of electronic components and the like, the heat dissipation device generally needs to be provided with fins to increase the heat exchange area due to high heat flux density.

There are many fin structures for enhancing heat exchange, and common ones include straight fins, corrugated fins, pin fins, radial fins, and the like. The fin body of the straight fin is in a slender strip shape, so that the heat exchange area can be increased in the direction perpendicular to a heat source, and the straight fin has the advantages of simple structure and easiness in processing and is also widely applied. One way to increase the heat dissipation capacity of straight fins is to increase the fin height and reduce the fin thickness. However, the two changes in shape both cause the efficiency of the fins to be reduced, the heat dissipation capacity per unit heat exchange area to be reduced, and more pressure drop is also introduced. Furthermore, as the fluid travels along the straight fins, both the velocity boundary layer and the thermal boundary layer slowly thicken, thereby attenuating the heat transfer performance in the direction of flow. Corrugated fins also suffer from the problems described above.

Radial fins such as described in patent CN110198615B, a structure using straight fins to form diverging flow channels and increasing the number of fins in the flow direction. The design can break through the increased fins and the boundary layers on the surfaces of the fins, so that the heat dissipation performance is improved. However, the fin base plate has an irregular shape, and it is difficult to use the entire effective heat dissipation area. In addition, the closer the channel is to the inlet, the more the fins are doubly sparse, the heat dissipation capacity is greatly reduced, and hot spots can be formed; the closer to the outlet, the more the fins are doubly packed, introducing excessive pressure drop.

Patent CN103503591B describes a pin-shaped fin array structure, in which the fin body is cylindrical, and special-shaped flow guiding structures are respectively arranged on the windward/leeward sides of the cylinder. Adjacent rows of pin fins are staggered to increase turbulence. Such pin fins are also known as square (US6273186B1), round (US6173758B1), oval (US20090145581a1) and the like. Most of the pin-shaped fin array designs adopt a staggered arrangement mode to enhance disturbance and strengthen heat dissipation. Due to the design, excessive bent channels are introduced into the flow field, the actual flowing length of the working medium is doubled, and therefore the pressure drop is high. The diamond fin array used in CN102713490A is in an in-line manner. However, the secondary flow in the secondary channel may collect the flow toward one side of the heat sink, thereby making the heat exchange capacity of the other side poor. And the flow velocity is increased due to the collection, and the pressure loss caused by the secondary flow can increase the pressure drop of the system, and the total pressure drop is even higher than that of the straight fins.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a reinforced heat dissipation device using array heat dissipation fins, which solves the problems of large pressure drop and poor heat exchange capacity caused by secondary flow convergence of the conventional fin structure.

In order to solve the technical problems, the utility model adopts the following technical scheme: an enhanced heat dissipation device using array heat dissipation fins is characterized in that: the cooling medium recovery device comprises a fin substrate, radiating fins and a cover plate, wherein the fin substrate and the cover plate surround a hollow cavity with two open ends; the radiating fins are trapezoidal or triangular, are positioned at the top of the fin substrate and are distributed in the hollow cavity; the radiating fins perpendicular to the flowing direction of the cooling medium are uniformly distributed at equal intervals, the radiating fins parallel to the flowing direction of the cooling medium are uniformly distributed at equal intervals, and the adjacent radiating fins are centrosymmetric.

The further technical scheme is that when the radiating fins are trapezoidal fins, the trapezoids are isosceles trapezoids, the length of a long side is 1-3.5 mm, the length of a short side is 0.1-0.7 mm, and the thickness is 0.1-0.6 mm; a secondary channel is formed between adjacent and parallel bevel edges, the distance between the secondary channels is 0.1-0.4 mm, a main channel is formed between adjacent long edges and short edges, and the distance between the main channels is 0.2-0.6 mm.

A further technical scheme is that when the radiating fins are triangular fins, the trapezoid is an isosceles triangle, the length of the bottom side is 1-3.5 mm, and the length of the waist side is 0.6-1.8 mm; secondary channels are formed between the adjacent and parallel inclined edges, the distance between the secondary channels is 0.1-0.4 mm, a main channel is formed between the adjacent bottom edges, and the distance between the main channels is 0.1-0.6 mm.

The further technical scheme is that the inner side wall of the cover plate is obliquely arranged, and a gap between the inner side wall of the cover plate and the top of the radiating fin is gradually reduced along the fluid direction.

A further technical scheme is that the inner side wall of the cover plate is convex downwards to form a convex part.

The working principle is as follows: the bottom surface of the fin substrate is in contact with the surface of an electronic component serving as a heating source, and a cooling medium flows through a channel formed by fins in the heat dissipation device to take away heat on the fin substrate and the heat dissipation fins, so that the purpose of dissipating heat for the electronic component is achieved. In the distribution of the radiating fin array, the cooling medium in the main channel is used as a main stream, the cooling medium in the secondary channel is used as a secondary stream, and the secondary stream periodically breaks away from the main stream and then flows into the main stream due to the fact that the secondary channel and the flow direction of the cooling medium form two complementary angles, so that the flow channel has a larger effective flow cross section area, the pressure drop is smaller, and the temperature distribution of a heat source is uniform. Meanwhile, the gap between the cover plate and the top of the fin is larger at the part, close to the upstream, of the radiating fin, and part of working medium is not in contact with the radiating fin array and directly flows away from the upper part of the radiating fin, so that the pressure drop is further reduced. At the part of the radiating fin close to the downstream part, because the gap between the cover plate and the top of the fin is reduced, all fluid enters the radiating fin array, and therefore the downstream heat exchange effect is ensured. In the radiating fin array, because the working medium has lower upstream temperature and flow and higher downstream temperature and flow, the temperature distribution of the heat source is uniform.

Compared with the prior art, the utility model has the beneficial effects that: the reinforced heat dissipation device with the array heat dissipation fins is simple in structure, the trapezoidal or triangular fins are arranged in an array which is uniform in flow direction of a cooling medium and is centrosymmetric, so that a main channel and a secondary channel are arranged in the heat dissipation fins, the secondary channel and the flow direction of the cooling medium form two complementary angles, wall surfaces in the secondary channel participate in convective heat transfer, and the heat transfer area is increased; meanwhile, the secondary flow is periodically separated from the main flow and then flows into the main flow, so that the boundary layer of the main flow is periodically broken and rebuilt, the flow is always in a development area, the heat source has a high convection heat transfer coefficient, the temperature distribution of the heat source is uniform, and the heat transfer capacity is improved. The secondary flow increases the flow cross-sectional area of the flow, and reduces the flow velocity of the main flow, thereby reducing the pressure drop. The inner side wall of the cover plate is obliquely arranged, so that part of working medium at the upstream is directly bypassed to the downstream, the pressure drop is reduced, and the temperature uniformity of a heat source is improved.

Drawings

Fig. 1 is an assembly schematic of the present invention.

Fig. 2 is a schematic diagram of an internal structure of the present invention.

Fig. 3 is another internal structure diagram of the present invention.

FIG. 4 is a schematic view showing the flow direction of the working medium in the present invention.

Fig. 5 is a flow line distribution diagram in the heat dissipating fin in example 1.

FIG. 6 is a graph comparing the distribution of the flow velocity field of the heat dissipating fins and the flat fins in example 1.

FIG. 7 is a graph comparing the temperature distribution of the heat source of the heat dissipating fins and the flat fins in example 1.

Fig. 8 is a schematic view of the internal structure of the present invention.

Fig. 9 is a flow line distribution diagram in the heat dissipating fin in example 3.

Fig. 10 is a flow velocity field profile of the fin of example 3.

Fig. 11 is a temperature distribution diagram of the heat dissipating fin in example 3.

In the figure: 1-fin base plate, 2-radiating fin, 3-cover plate, 301-convex part and 4-straight fin.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the utility model.

Example 1

Fig. 1 and 2 show an enhanced heat dissipation device using an array heat dissipation fin, which includes a fin substrate 1, a heat dissipation fin 2 and a cover plate 3, wherein the fin substrate 1 and the cover plate 3 enclose a hollow cavity with two open ends, one end of the hollow cavity is connected with a cooling medium supply device, and the other end of the hollow cavity is connected with a cooling medium recovery device. The section of the radiating fin 2 is an isosceles trapezoid, the length of a long side is 3mm, the length of a short side is 0.5mm, and the thickness of a single fin is 0.5 mm. The radiating fins 2 are positioned at the top of the fin substrate 1 and distributed in the hollow cavity; the radiating fins 2 perpendicular to the flowing direction of the cooling medium are uniformly distributed at equal intervals, the radiating fins 2 parallel to the flowing direction of the cooling medium are uniformly distributed at equal intervals, and the adjacent radiating fins 2 are centrosymmetric. A secondary channel is formed between the adjacent parallel oblique edges, the distance between the secondary channels is 0.3mm, a main channel is formed between the adjacent long edges and the short edges, and the distance between the main channels is 0.5 mm.

Now, the flow channel formed by the trapezoidal radiating fins and the conventional straight fins is used for comparison, and the number of the trapezoidal fins is 10X 19. Under the fins, there is a chip with heat source of 24mm × 18mm and power of 250W. The size of the inlet of the cooling medium (working medium) is 19.5mmX3mm, the working medium is purified water with the temperature of 30 ℃, and the inlet flow is 1 liter/minute. The straight fin structure is 19 elongated straight fins arranged in parallel, and the thickness, the width of a main channel, the size of the device, the operation working condition and the like of the straight fins are the same as those of the trapezoidal fins.

When the heat-conducting silicon-based fin substrate is used, the bottom surface of the fin substrate 1 is in contact with the surface of a chip serving as a heat-generating source, and heat-conducting silicone grease is coated between the bottom surface of the fin substrate and the surface of the chip. The cooling medium flows through the channel formed by the fins in the heat dissipation device, and takes away the heat on the fin substrate 1 and the heat dissipation fins 2, so that the purpose of dissipating heat for the chip is achieved. In the array distribution of the heat dissipation fins 2, the cooling medium in the main channel is used as a main stream, the cooling medium in the secondary channel is used as a secondary stream, and the secondary stream periodically breaks away from the main stream and then converges into the main stream due to the fact that the secondary channel and the flow direction of the cooling medium form two complementary angles as shown in fig. 4, so that the flow channel has a larger effective flow cross-sectional area, the pressure drop is smaller, and the temperature distribution of a heat source is uniform.

Fig. 5 is a streamline distribution diagram obtained after CFD simulation, and it can be seen that the flow in the primary channel is not obstructed and the secondary flow is generated in the secondary channel. Fig. 6 compares the distribution of the flow velocity field in the flow channel formed by the trapezoidal fins and the conventional straight fins in the present embodiment under the same working condition. As can be seen from fig. 6a, the flow velocity is higher and the boundary layer is thinner near the fins on both sides of the main channel in this embodiment. In contrast, the flow in the straight fins shown in fig. 6b quickly thickens after entering the flow channel.

Because the runner that trapezoidal fin structure constitutes has bigger effective cross sectional area that overflows, for conventional straight fin, the pressure drop of the whole runner of novel design is littleer. Under the operating condition, a novel fin heat dissipation device is used, and the pressure drop in the whole flow channel is 903 Pa; and the pressure drop in the whole flow passage is 1022Pa by adopting the heat dissipation device with the conventional straight fins.

Fig. 7 compares the temperature distribution of the heat source after the heat sink employing two fin structures in terms of heat transfer performance. As can be seen, the use of trapezoidal fins results in a more uniform temperature distribution of the heat source and lower maximum temperatures (fig. 7 a). While the straight fins present distinct hot spots downstream of the flow channel (fig. 7 b). Specifically, after the trapezoidal fins are adopted, the highest temperature of a heat source is 48.3 ℃; and after the conventional straight fins are adopted, the highest temperature of a heat source reaches 50.3 ℃.

Example 2

Fig. 3 shows an enhanced heat dissipation device using an array heat dissipation fin, which includes a fin substrate 1, a heat dissipation fin 2 and a cover plate 3, wherein the fin substrate 1 and the cover plate 3 enclose a hollow cavity with two open ends, one end of the hollow cavity is connected with a cooling medium supply device, and the other end of the hollow cavity is connected with a cooling medium recovery device. The section of the radiating fin 2 is an isosceles triangle, the length of the bottom edge is 3mm, the length of the waist is 1.7mm, and the thickness of a single fin is 0.5 mm. The radiating fins 2 are positioned at the top of the fin substrate 1 and distributed in the hollow cavity; the radiating fins 2 perpendicular to the flowing direction of the cooling medium are uniformly distributed at equal intervals, the radiating fins 2 parallel to the flowing direction of the cooling medium are uniformly distributed at equal intervals, and the adjacent radiating fins 2 are centrosymmetric. Secondary channels are formed between the adjacent parallel bevel edges, the distance between the secondary channels is 0.3mm, a main channel is formed between the adjacent bottom edges, and the distance between the main channels is 0.5 mm.

Example 3

In order to further improve the heat dissipating capability of the heat dissipating device, as shown in fig. 8, a convex portion 301 is formed by downwardly protruding the inner sidewall of the cover plate 3, so that the gap between the inner sidewall of the cover plate 3 and the top of the heat dissipating fin 2 becomes smaller in the fluid flow direction. The total length of the heat radiating fin 2 in the working medium flow direction is 27.15mm, and the length of the convex portion 301 in the working medium flow direction is 15.15 mm. The end surface of the convex part 301 close to the working medium outlet direction is flush with the tail end of the radiating fin 2 close to the working medium outlet direction.

Fig. 9 is a flow line distribution diagram obtained after CFD simulation, and it can be seen from the diagram that a part of the working medium directly bypasses the gap formed by the inner side wall of the cover plate 3 and the top of the heat dissipation fin 2 to flow to the outlet at the upstream of the heat dissipation fin 2. The bypassed working medium is blocked by the convex part 301 and flows into the downstream radiating fin 2. Fig. 10 is a flow velocity field in the middle vertical section of a heat sink. As can be seen from the figure, because part of the working medium directly bypasses from the top of the radiating fin 2, the flow velocity of the working medium in the radiating fin 2 is lower at the upstream part and higher at the downstream part.

Because the working medium is directly bypassed at the upstream part of the radiating fin 2, the effective flow cross section area is larger, and the pressure drop is lower. Under the same operating conditions as described in example 1 above, the pressure drop across the flow passage was 739Pa after using the cover plate 3 with the projections 301.

In terms of heat transfer performance, fig. 11 shows the temperature distribution of the heat source after the cover plate 3 having the convex portion 301 is used. Comparing with fig. 7a, it can be seen that the temperature distribution of the heat source is more uniform. A region with lower temperature appears in the middle of the heat source, which corresponds to the position where the working medium flows down into the heat dissipation fins 2 after being blocked by the convex part 301. Therefore, the hot spot is divided into two parts by one, and the temperatures of the two hot spots are lower. Specifically, the maximum temperature of the heat source was 48.1 ℃.

Although the utility model has been described herein with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, other uses will also be apparent to those skilled in the art.

Claims

1. An enhanced heat dissipation device using array heat dissipation fins is characterized in that: the cooling fin structure comprises a fin substrate (1), radiating fins (2) and a cover plate (3), wherein the fin substrate (1) and the cover plate (3) surround a hollow cavity with two open ends, one end of the hollow cavity is connected with a cooling medium supply device, and the other end of the hollow cavity is connected with a cooling medium recovery device; the radiating fins (2) are trapezoidal or triangular, and the radiating fins (2) are positioned at the top of the fin base plate (1) and distributed in the hollow cavity; the radiating fins (2) perpendicular to the flowing direction of the cooling medium are uniformly distributed at equal intervals, the radiating fins (2) parallel to the flowing direction of the cooling medium are uniformly distributed at equal intervals, and the adjacent radiating fins (2) are centrosymmetric.

2. An enhanced heat dissipation device using an array of heat dissipation fins as claimed in claim 1, wherein: when the heat dissipation fins (2) are trapezoidal fins, the trapezium is an isosceles trapezoid, the length of a long side is 1-3.5 mm, the length of a short side is 0.1-0.7 mm, and the thickness is 0.1-0.6 mm; a secondary channel is formed between adjacent and parallel bevel edges, the distance between the secondary channels is 0.1-0.4 mm, a main channel is formed between adjacent long edges and short edges, and the distance between the main channels is 0.2-0.6 mm.

3. An enhanced heat dissipation device using an array of heat dissipation fins as claimed in claim 1, wherein: when the radiating fins (2) are triangular fins, the trapezoid is an isosceles triangle, the length of the bottom side is 1-3.5 mm, and the length of the waist is 0.6-1.8 mm; secondary channels are formed between the adjacent and parallel inclined edges, the distance between the secondary channels is 0.1-0.4 mm, a main channel is formed between the adjacent bottom edges, and the distance between the main channels is 0.1-0.6 mm.

4. An enhanced heat dissipation device using an array of heat dissipation fins as claimed in claim 1, wherein: the inner side wall of the cover plate (3) is obliquely arranged, and a gap between the cover plate and the top of the radiating fin (2) is gradually reduced along the fluid direction.

5. An enhanced heat dissipation device using an array of heat dissipation fins as claimed in claim 4, wherein: the inner side wall of the cover plate (3) is downwards protruded to form a convex part (301).