CN107426950A - A kind of electronic device natural heat dissipation device - Google Patents

Abstract

A natural heat dissipation device for an electronic device, the heat dissipation device is composed of a substrate, a heat dissipation fin arranged on the substrate, and a rear case; the heat dissipation fin adopts a W-shaped structure, arranged vertically to the substrate, and interrupted at the corner; The back shell is made of heat-insulating material and is attached to the back of the substrate. During the working process, the cooling device is vertically arranged, and the heat generated by the electronic device is transferred to the aluminum plate through the heat pipe. The cooling fins dissipate heat to the environment. Using the unique arrangement of W-shaped fins, the heat dissipation area is increased, the contact process between the gas and the fins is reduced, the air intake in the horizontal direction is greatly increased, the heat transfer temperature difference becomes larger, and the natural convection heat transfer efficiency is improved. , so as to achieve the purpose of prolonging the life of electronic devices and improving the reliability of equipment.

Description

A natural cooling device for electronic devices

technical field

The invention belongs to the technical field of heat dissipation, and specifically relates to a natural heat dissipation device for electronic devices under high heat flux density, which is suitable for chemical industry, metallurgy, air conditioning, electronic communication and other industries that need to strengthen heat dissipation.

Background technique

With the rapid development of electronics and communication technology, high-performance chips and integrated circuits are used more and more widely. The development of the electronics industry has always followed Moore's Law: when the price remains constant, the number of transistors that can be accommodated on an integrated circuit will double every 18 to 24 months, and the performance will also double. Therefore, the power of the electronic device chip is continuously increasing, and the volume of the equipment is decreasing day by day, which leads to the continuous increase of the heat flux on the unit surface of the equipment and the continuous rise of the temperature. As temperature increases, the failure rate of electronic components increases exponentially when their ratings are exceeded, correspondingly reducing the reliability of the equipment. In order to ensure the stability of electronic equipment system parameters and improve the performance and reliability of electronic equipment, it is necessary to thermally design the equipment so that its operating temperature is lower than the rated temperature. At present, the main cooling methods of electronic devices are active and passive. Generally speaking, the amount of active heat dissipation is much greater than that of passive heat dissipation. However, due to the advantages of no energy supply, reliable and stable performance, high safety, no noise and low manufacturing cost, passive heat dissipation has attracted more and more attention. Moreover, due to environmental adaptability requirements, some products do not allow fans to be installed inside, and their casings are relatively sealed. Usually, the concentrated heat source is installed on the bottom of the device or inside the casing, and the heat dissipation area is increased by means of cooling ribs or fins. Heat dissipation through natural heat dissipation.

For natural heat dissipation modules widely used in communication and network industries, the analysis of the heat dissipation process from the heat source (heating element) inside the module to the external environment shows that the heat dissipation thermal resistance on the side of the module shell is much greater than the contact thermal resistance inside the module, as well as heat conduction and convection. Etc. link thermal resistance. The heat dissipation on the shell side includes natural convection heat dissipation and radiation heat dissipation, especially the high natural convection thermal resistance (accounting for more than 50% of the entire module thermal resistance), which is the key to restricting the improvement of the module's heat dissipation capability. As the power consumption of natural heat dissipation modules continues to increase, how to fully reduce the thermal resistance of the natural heat dissipation module shell side and enhance the heat dissipation capacity of the module is an inevitable requirement to reduce the temperature level of the module and a prerequisite for ensuring the normal and stable operation of the natural heat dissipation module. Considering the limitation of the surface condition and temperature level of the module, the enhancement and optimization space of the radiation heat transfer is limited, so the enhanced heat transfer of the natural heat dissipation module is mainly to enhance the natural convection heat dissipation capacity of the shell side, so previous researchers have done this A large number of experiments and numerical simulation studies have been carried out. The fin structures currently used in natural convection cooling modules mainly include flat fins, corrugated fins and louver fins. Flat fins have the advantages of convenient processing, low manufacturing cost, and large-scale production. However, for the vertical flat fins that are often used in actual production, the upper part of the fins has a smaller heat transfer temperature difference due to the higher airflow temperature. Therefore, its heat dissipation capability also deteriorates accordingly. Corrugated fins and louver fins have complex structures, difficult processing, and large flow resistance, and the upper part of the vertical corrugated fins and louver fins used in actual production also has a flow field similar to that of vertical flat fins. The disadvantage of poor synergy between velocity vectors and temperature gradients. In view of this, the thermal design of equipment has become a key issue restricting the development of new technologies in industries such as electronic communications. Therefore, there is an urgent need to develop a high-efficiency heat sink that can significantly reduce the internal temperature of electronic equipment under high heat flux and improve equipment reliability.

Contents of the invention

Aiming at the above-mentioned technical problem that the airflow temperature on the upper part of the vertical flat fins is high and the flow velocity is small, the effect of natural convection heat transfer is deteriorated. A natural heat dissipation device for electronic devices that prolongs life and improves equipment reliability.

In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: including the heat-insulating rear shell, the heat source aluminum plate, the base plate and the W-shaped heat dissipation fins arranged in sequence from bottom to top, and the corners of the W-shaped heat dissipation fins are disconnected and arranged symmetrically On the base plate; the aluminum plate of the heat source is arranged in the heat-insulating back shell, and is closely attached to the back of the base plate.

The opening angle a of the W-shaped cooling fins is 45°-90°.

The ratio d/L of the dimension d of the disconnected part of the W-shaped heat dissipation fin to the width dimension L of the substrate is 0.03˜0.10.

The ratio l/p of the fin thickness l of the W-shaped heat dissipation fins to the width dimension L of the fin pitch p=0.05˜0.10.

The W-shaped cooling fins are uniformly arranged on the substrate. The heat insulation treatment of the rear shell.

The heat generated by the electronic device is transferred to the heat source aluminum plate through the heat pipe, and the heat source aluminum plate is bonded to the heat sink substrate, and finally dissipates the heat to the environment through the W-shaped heat dissipation fins. Compared with the air intake at the bottom of the vertical flat fins, the W-shaped cooling fins change the air intake mode, allowing more air to enter from the horizontal direction, increasing the heat exchange temperature difference and increasing the heat exchange area. Thereby greatly improving the heat exchange efficiency.

Compared with the prior art, the present invention has the following advantages:

1) Increased heat transfer area. Compared with the traditional vertical flat fins, the inclined fin arrangement of W-shaped fins makes more efficient use of the heat dissipation space. While ensuring the heat dissipation efficiency of the fins, it increases the heat transfer area and enhances the heat transfer effect.

2) The air intake method has been changed. The traditional vertical flat fins mainly take in air from the bottom, and the air rises in the direction of gravity to exchange heat with the fins. The direct result of this air intake method is that the temperature of the air above the substrate gradually increases, and the heat transfer temperature difference becomes smaller; at the same time, due to the relatively large air intake process and the large thickness of the thermal boundary layer, the heat transfer performance deteriorates. The W-shaped heat dissipation fins make the main way of air intake is horizontal air intake, so that more cold air directly enters the vicinity of the fins and participates in the heat exchange process, which reduces the gas flow and increases the heat exchange temperature difference. The overall heat transfer performance is enhanced.

3) Increased air intake. The air intake in the horizontal direction of the W-shaped cooling fin is mainly at the interrupted part of the fin corner. Compared with V-shaped fins, W-shaped fins greatly increase the air intake in the horizontal direction, so that more air can reach the bottom of the fins, and even wash the substrate, thereby achieving the purpose of enhancing heat dissipation.

4) The present invention is simple in structure. On the basis of the traditional vertical flat plate heat dissipation structure, the height of the fins is not changed, and the original heat dissipation space is retained, only the arrangement of the fins is changed; the oblique ribs and arc structures are not added, and the flow resistance is effectively retained, and the processing is convenient , low manufacturing cost and other advantages.

5) High heat dissipation efficiency. When the power of the electronic device is 100W and the ambient temperature is 25°C, the finned radiators widely used in the industry are based on the traditional vertical flat radiators, and the average temperature of the substrate is less than 2.5°C, which can be achieved by using the heat pipe technology. The average temperature drop is 3.8°C, while the W-shaped cooling fins in the present invention can achieve the highest temperature drop of 5.1°C, and the average temperature drop is 3.9°C.

Description of drawings

The following embodiments are described in conjunction with the accompanying drawings to further illustrate the present invention.

Figure 1 is an exploded view of the present invention.

Figure 2 is a front view of the present invention.

Fig. 3 is a left view of the present invention.

Fig. 4 is a comparison diagram of the temperature of the temperature measuring point between the structure of the present invention and the traditional vertical flat fin radiator.

In the figure, 1. W-shaped heat dissipation fins, 2. base plate, 3. heat source of aluminum plate, 4. heat-insulating back shell.

detailed description

Referring to accompanying drawing 1, heat dissipating device of the present invention comprises W-shaped cooling fin 1 and the substrate 2 that is arranged on the bottom of described W-shaped cooling fin 1, and the heat source aluminum plate 3 that is close to the back side of described substrate 2, and package all The heat-insulating back shell 4 of the heat source aluminum plate 3; the corners of the W-shaped heat dissipation fins 1 are disconnected and evenly distributed on the substrate 2. Wherein, the opening angle a of the W-shaped heat dissipation fin 1 is 45° to 90°; the ratio of the dimension d of the disconnected part of the W-shaped heat dissipation fin 1 to the width dimension L of the substrate 2 is d/L=0.03～ 0.10; the ratio l/p of the thickness l of the W-shaped heat dissipation fin 1 to the width dimension L of the fin pitch p=0.05˜0.10.

The heat generated by the electronic device is transferred to the heat source of the aluminum plate through the heat pipe, and then the heat source of the aluminum plate is bonded to the heat sink substrate, and finally the heat is dissipated to the environment through the W-shaped heat dissipation fins. By changing the way of air intake, more air is taken in from the horizontal direction and quickly leaves the fin area along the inclined channel, which reduces the air flow, increases the heat exchange temperature difference, and increases the heat exchange area. Thereby greatly improving the heat exchange efficiency.

The following is an embodiment of the present invention, the height H of the substrate is 355 mm, the width L of the substrate is 210 mm, and the thickness b of the substrate is 3 mm. For w-type cooling fins, the opening angle a is 60°, the fin thickness l is 1.8mm, and the fin spacing p is 11.2mm. Five temperature measurement points are evenly arranged on the substrate. The total power of the five heat sources is 100W, and they are all arranged on the substrate, and the ambient temperature is 35°C. Aiming at this structural parameter, the heat transfer and flow characteristics of the traditional vertical flat fin radiator and the structure of the present invention are numerically calculated, and the temperature distribution on the substrate of the two structures is compared and analyzed. Using the high-efficiency electronic device radiator, compared with the traditional vertical flat-fin radiator, the temperature distribution of the five temperature measurement points is shown in Figure 3. It can be seen from Fig. 3 that, compared with the traditional vertical flat-fin radiator, the structure of the present invention can reduce the maximum substrate temperature by about 5.1°C, which significantly enhances convective heat transfer.

Claims (5)

1. A kind of 1. electronic device natural heat dissipation device, it is characterised in that：Including set gradually from bottom to top adiabatic rear shell (4), Thermal source aluminium sheet (3), substrate (2) and W types radiating fin (1), W types radiating fin (1) corner disconnect, and are arranged symmetrically in base On plate (2)；The thermal source aluminium sheet (3) is arranged in adiabatic rear shell (4), and is close to substrate (2) back side.
2. 2. electronic device natural heat dissipation device according to claim 1, it is characterised in that：Described W types radiating fin (1) Opening angle a be 45 °~90 °.
3. 3. electronic device natural heat dissipation device according to claim 1, it is characterised in that：Described W types radiating fin (1) Disconnect the ratio between spot size d and substrate (2) width dimensions L d/L=0.03~0.10.
4. 4. electronic device natural heat dissipation device according to claim 1, it is characterised in that：Described W types radiating fin (1) The ratio between fin thickness l and spacing of fin p width dimensions L l/p=0.05~0.10.
5. 5. electronic device natural heat dissipation device according to claim 1, it is characterised in that：Described W types radiating fin (1) It is evenly arranged on substrate (2).