CN101237755B - The turbulent heat dissipation upper cover corresponding to the top surface of the heating element and the heat dissipation assembly with the upper cover - Google Patents

Abstract

A turbulent flow heat radiation upper cover and heat radiation assembly with the upper cover, the heat radiation upper cover defines an air channel together with the top surface of the heating element by a top wall and a spacing device, the structure is quite simple, the manufacturing cost is low, and the air flow in the air channel conforms to Reynolds number Re ═ rho umd)/mu ≥ 2,500; wherein ρ is the airflow density; um is the airflow speed in the air duct; d is the size of the air duct; mu is airflow viscosity. Because the turbulent flow is formed in the air duct, the heat exchange of the gas in the air duct is frequent, and the temperature difference gradient between the gas layer and the interlayer is obvious, so that the cooling efficiency is greatly improved, only the gas needs to be introduced, the operating condition is quite single, the heating piece with higher efficiency is allowed to be adopted, and the element selection elasticity of the electronic equipment adopting the heat dissipation upper cover is improved.

Description

The turbulent heat dissipation upper cover corresponding to the top surface of the heating element and the heat dissipation assembly with the upper cover

Technical field:

The invention relates to a heat dissipation upper cover, in particular to a heat dissipation upper cover for forming turbulent flow, and a heat dissipation assembly with the upper cover.

Background technique:

With the increasingly high integration of semiconductor components, the circuits integrated in a single semiconductor component are becoming more and more complex, and the power consumption and heat generation are greatly increased. On the other hand, once the temperature of the operating environment exceeds about 120 degrees Celsius, not only the material of the silicon chip itself may be damaged, but the solder that is responsible for electrically connecting the semiconductor element to the circuit board will also melt due to reaching the melting point. The conduction between the components and the circuit board brings problems, and also causes troubles such as contamination of the circuit board.

Therefore, no matter on the main board, video display card, or other occasions that need to use high-performance semiconductor components, as shown in Figure 1, a layer of heat-conducting adhesive 14 is coated on the top surface of the heat-generating semiconductor component 10 for pasting to install a heat dissipation The fins 16 even further add a heat dissipation fan 18 on the heat dissipation fins 16, so that the heat energy generated by the semiconductor element 10 on the circuit board 12 can be exported through the heat dissipation fins 16 conduction and air convection, so as to avoid continuous accumulation of heat energy cause damage to the semiconductor element 10.

In addition, as shown in Fig. 2 U.S. Patent No. 6,603,658, the invention discloses an air duct 26 to guide the air supply from the fan 28, so that the air flow is directed to the heating element on the circuit board 22 in a stable laminar flow mode 20, so as to derive the heat energy generated by the heating element 20, thereby reducing the operating environment temperature of components in, for example, a notebook computer.

Its air duct 26 as shown in Figure 3 does not really contact the heating element 20, and the distance between the outlet of the air duct 26 and the heating element 20 is several times the size of the opening of the air duct 26. Therefore, the airflow 280 from the air duct 26, It will slowly pass through the heating element 20 in a stable flow mode of laminar jet air flow, and even form a stagnation region (stagnation region) in the contact area between the surface of the heating element 20 and the air flow for heat exchange, in order to maintain a stable laminar flow As a result, the Reynolds number of the inflowing gas in this scheme is Re=(ρumd)/μ≤2,000; among them, ρ is the airflow density; um is the airflow velocity in the air duct; d is the air duct size; μ is the airflow viscosity.

However, for electronic devices such as industrial computers that generate a lot of heat, the heat dissipation effect of laminar gas alone is obviously insufficient; especially when more highly integrated circuit components are used, the density of semiconductor components on the circuit board is increased, or When more circuit components are used, the heat generated in a local area will be greatly increased, and the heat dissipation capability of electronic equipment will become the biggest bottleneck for performance improvement.

Therefore, many electronic devices rely on setting pipes to feed water or other fluids, and take advantage of the high specific heat and high heat capacity characteristics of liquid fluids to take away a large amount of heat energy; however, laying pipes between circuits requires not only the introduction of fluids, but also In order to completely export the fluid, it is necessary to provide an additional closed space for setting the fluid circuit in a limited space; and be careful at all times to avoid any small leakage that may cause a short circuit and affect the overall safety, making this solution quite potentially dangerous.

In contrast, another safer solution is to pass liquid gas such as liquid nitrogen or low-temperature air, and carry away a large amount of heat energy by expanding the temperature difference between the gas and the heating element. However, the cost of reducing the temperature of the gas in this way is very high, and the low-temperature gas needs to remove the moisture in it first, so as to avoid the increase of the relative humidity of the gas during the cooling process, causing water droplets to condense on the circuit components.

If the heat dissipation performance can be improved without reducing the temperature of the incoming gas, it will not only ensure the smooth operation of the circuit, avoid unnecessary energy consumption and humidity problems, but also improve the flexibility of selecting circuit components and effectively improve product performance. Therefore, this It is a topic worthy of in-depth study.

Invention content:

Therefore, one of the technical problems to be solved by the present invention is to provide a heat dissipation upper cover that can greatly improve the cooling effect.

Another technical problem to be solved by the present invention is to provide a heat dissipation upper cover with a simple structure.

Another technical problem to be solved by the present invention is to provide a heat dissipation upper cover with single operating conditions.

Another technical problem to be solved by the present invention is to provide a heat dissipation upper cover with low manufacturing cost.

Another technical problem to be solved by the present invention is to provide a heat dissipation assembly that greatly increases the flexibility of selected circuit components.

Therefore, the turbulent heat dissipation upper cover of the present invention is used to connect an air supply device with a predetermined amount of air supply, and accept the airflow from the air supply device to derive the heat energy generated by the heating element, and the heating element is set On a circuit board, the heat dissipation upper cover includes a heat dissipation upper cover body, and the body includes: a top wall; , and together with the top wall and the top surface of the heating element define a spacer for an air duct, and the air duct makes the airflow Reynolds number Re=(ρumd)/μ≥2,500 from the air supply device ; Among them, ρ is the airflow density; um is the airflow velocity in the air duct; d is the air duct size; μ is the airflow viscosity.

The turbulent heat dissipation upper cover provided by the present invention also has the following subsidiary technical features:

The spacer includes two side walls extending from the top wall, and a bottom wall opposite to the top wall, and the bottom wall is formed with an opening corresponding to the size of the top surface of the heating element.

The turbulent heat dissipation upper cover also includes a fixing device for fixing the heat dissipation upper cover body to the circuit board.

In a preferred embodiment of the present invention, a plurality of clamping slots are formed on the circuit board, and the fixing device includes: a surrounding piece that roughly covers the fixed upper cover body; and a The locking pieces extend from the bottom of the surrounding piece and respectively correspond to the locking slots.

In another preferred embodiment of the present invention, the fixing device includes: a surrounding part that roughly covers the fixed upper cover body; a plurality of warping parts bent and extending from the bottom of the surrounding part at an angle part; and a buckle fixed on the circuit board and corresponding to the warping part.

In another preferred embodiment of the present invention, a plurality of fixing holes are formed on the circuit board, and the body of the turbulent heat dissipation upper cover also extends with a plurality of side wings formed with through holes. The device is a plurality of bolts passing through the through holes of the side wings and the fixing holes.

According to the heat dissipation assembly provided by the present invention, it is used to derive the heat energy generated by a heating element arranged on a circuit board. The heat dissipation assembly includes: a turbulent heat dissipation upper cover corresponding to the top surface of the heating element, the The heat dissipation upper cover includes a heat dissipation upper cover body, and the body includes: a top wall; The top surface of the heating element jointly defines a spacer for an air duct; and a spacer that connects the air duct and makes the air flow in the air duct Reynolds number Re=(ρumd)/μ≥2,500 to supply air to the air duct Air supply device; where, ρ is the airflow density; um is the airflow velocity in the air duct; d is the air duct size; μ is the airflow viscosity.

The heat dissipation upper cover also includes a fixing device for fixing the heat dissipation upper cover body to the circuit board.

The air supply device is a blower fan.

The present invention injects a large amount of gas, forces the gas to generate a turbulent flow, increases the convection of the gas between the layers, and speeds up the speed of reaching the heat balance. Not only the structure is simple, the cost is low, and the operation process does not need to reduce the temperature of the gas, There is no need to reduce the humidity of the injected gas, and the risk of introducing fluid is eliminated. Under the original simple operating environment conditions, with a simple structure, the cooling efficiency can be improved at the same time, and unnecessary energy consumption can be avoided. The flexibility is greatly increased, and the reliability and stability of the circuit are greatly improved, thereby solving all the technical problems that the present invention intends to solve.

Description of drawings:

FIG. 1 is a schematic diagram of a state in which a conventional radiator and a semiconductor element are assembled on a circuit board;

Fig. 2 is a schematic side view of the application state of the US Patent No. 6,603,658 radiator;

Fig. 3 is a schematic diagram of the airflow generated by the radiator shown in Fig. 2;

Fig. 4 is a perspective schematic diagram of a heat dissipation upper cover in the first preferred embodiment of the present invention;

Fig. 5 is a schematic diagram of the airflow in the air duct of the preferred embodiment shown in Fig. 4;

Fig. 6 is a schematic diagram of the convection and heat flow states and a schematic diagram of the temperature distribution state of each layer in the air duct shown in Fig. 5;

Fig. 7 is a side view structural schematic view of the second preferred embodiment of the present invention;

Fig. 8 is a side view structural schematic view of the third preferred embodiment of the present invention;

Fig. 9 is a schematic side view of the structure of the fourth preferred embodiment of the present invention.

[Description of main component symbols]

3, 3’, 3”...heat dissipation cover 26...air duct

3"'...Heat Dissipating Cover Body 30...Air Duct

4...Air supply device 32...Top wall

10...Heating semiconductor components 34...Spacer device

12, 22...circuit board 280...airflow

14...thermal adhesive 300...conducting part

16...radiating fins 302...the bottom layer

18, 28...fan 304, 306...upper layer

20...Heating element 308...Upper layer

380...plane 802...warping part

381...Curved surface 804...Snap fasteners

382...turbulent flow 902...fixing hole

70, 80...surrounding parts 904...flanks

700...Clamping slots 906...Bolts

702...Clamp parts

Detailed ways:

The foregoing and other technical content, features and effects of the present invention will be clearly presented in the following detailed description of preferred embodiments given with the accompanying drawings.

The turbulent heat dissipation upper cover 3 of the first preferred embodiment of the present invention, as shown in FIG. The top wall is opposite to the bottom wall, and the bottom wall is formed with an opening corresponding to the size of the top surface of the heating element 20 for covering the heating element 20 and making the turbulent heat dissipation upper cover 3 firmly arranged on the circuit board 22 . The top wall 32 , the spacer 34 and the heating element 20 jointly define an air channel 30 , and the air channel 30 has a connecting portion 300 for connecting to a blower fan serving as the air supply device 4 .

The airflow from the air supply device 4 will enter the air duct 30 through the guide part 300, and the air duct 30 has a predetermined cross-sectional size, so that the Reynolds number of the airflow flowing into the air duct 30 Re=(ρumd)/μ≥ 2,500, thus forming a turbulent flow; wherein, ρ is the airflow density; um is the airflow velocity in the air duct 30; d is the size of the air duct 30; μ is the airflow viscosity. Thus, the heat energy generated by the heating element 20 is conducted into the heat dissipation upper cover 3 through the air flow, and due to the heat exchange between the air flow and the gas in the air duct 30, the heat generated by the heating element 20 is carried out by the air flow.

As shown in Figure 5, generally the fluid enters the flow channel at a predetermined speed. At the beginning, the flow velocity distribution will be as shown on the right side of the figure: it advances side by side with a plane 380, and then due to the friction between the wall surface of the air channel 30 and the fluid molecules, and the fluid molecules The viscous effect of itself makes the flow velocity of the fluid closer to the wall of the air duct 30 gradually slow down and eventually stop; on the contrary, the fluid near the center of the air duct 30 is less affected, so that the flow velocity distribution forms the central part of the figure The curved surface 381 is laminar. On the other hand, if the flow velocity is too fast or the fluid viscosity is too low, the actual travel direction of each fluid molecule has different vertical components, resulting in the interactive flow between layers, and the formation of Turbulent flow 382 on the left.

Further consider the temperature distribution inside and outside the air duct, as shown on the left side of Figure 6, when the heating element 20 is located below the air duct 30 in the figure, the heat generated by the heating element 20 will be gradually introduced into the air duct 30 through the conduction of the airflow middle. In addition, the room temperature gas is forced into the air duct 30 to make it flow from right to left. If the gas in the air duct 30 maintains a good laminar flow structure as shown by the dotted line, only the gas in the lowermost layer 302 and the air duct 30 The wall will conduct heat exchange, and when the gas molecules in the layer 302 gradually absorb heat energy and heat up, the temperature difference between the gas and the air duct 30 will decrease, and the heat exchange rate will gradually decrease; The lack of convection and the difficulty in conduction make the upper layer 308 gas still at room temperature, but it does not benefit the temperature rise of the lowermost layer 302 gas.

On the contrary, if the fluid tends to be in a turbulent flow state, the gas convection between the layers is strong, and the gas in the lowermost layer 302 absorbs part of the heat energy of the gas from the air duct 30, and then flows to the upper layers 304, 306, and then the upper layers 304, 306 The room temperature gas also flows downward randomly, so the temperature difference between the gas in the lowermost layer 302 and the gas in the air duct 30 can be kept at a relatively significant temperature difference state, thereby improving the heat exchange efficiency. Thereby, as shown on the right side of FIG. 6 , when the incoming air is about 25 degrees Celsius, the temperature of the gas in the air duct can be maintained at about 70 degrees Celsius, so that the heat energy absorbed by the gas in the air duct 30 is absorbed by the upper layers 308, 306, 304 and the gas molecules in the lower layer 302 are jointly carried and transported.

In order to prove the above conclusion, the inventor used two resistors of 40 watts each as heating elements. Without any auxiliary condition of radiator, the core temperature of the resistors can rise to about 170 degrees Celsius; of course, as mentioned above, if Taking the semiconductor element as a comparison, at this temperature, the semiconductor chip has been damaged by heat. When the air is not forced into, and the heat dissipation upper cover of the present invention is used as a heat conduction device alone, the core temperature of the resistor during operation can still reach 110 degrees Celsius; After conditioning, the temperature of the resistance core plummeted to 70 degrees Celsius. At present, the power of a single integrated circuit element is only 4 or 5 watts, that is, with the heat dissipation cover used in the experiment of the present invention, at least 20 integrated circuit elements can be smoothly operated in a safe operating environment.

In particular, the difference in core temperature between the upstream heating element and the downstream heating element located upstream and downstream of the air duct is less than 2 degrees Celsius, which means that the ability of the airflow in the radiator to carry heat away is still far from being saturated. What's more, the air that is introduced is room temperature air, not only is there no humidity problem, but also the outlet of the radiator can be opened, allowing the slightly heated airflow to disperse inside the electronic equipment, without any safety concerns of the liquid cooling device.

On the other hand, the same experiment was conducted with thermally conductive materials with slightly different thermal resistance, such as copper and aluminum, and it was found that there was no significant difference in the effect of lowering the temperature. Manufactured from processed thermally conductive metals without being limited by the material.

Of course, those skilled in the art can easily understand that the turbulent flow space formed in the previous embodiment can function in different forms, as shown in the second preferred embodiment of the present invention in FIG. The mutual positional relationship between the circuit board 22 and the heating element 20 is that the circuit board 22 is formed with a plurality of clamping slots 700, and the surrounding component 70 roughly wraps and fixes the body of the upper cover 3'; the bottom of the surrounding component 70 has an extended clamping component 702, The clamping parts 702 respectively correspond to the above-mentioned clamping slots 700. By interlocking the clamping parts 702 and the clamping slots 700 one by one, the heat dissipation upper cover 3' and the circuit board 22 are fixed. As long as the Reynolds number in the air duct Above 2500, the airflow becomes a turbulent flow, which can achieve the same effect.

Referring again to FIG. 8 , according to the third preferred embodiment provided by the present invention, the surrounding part 80 roughly wraps and fixes the upper cover body 3 ", and the bottom of the surrounding part 80 has multiple bends extending from the bottom of the surrounding part 80 at an angle. The warping portion 802; the circuit board 22 has a buckle 804 fixed on the circuit board 22 and corresponding to the warping portion 802, and its fixing method is different from the aforementioned second preferred embodiment. But as long as the defined airflow space can The turbulent flow is formed, and the expected heat dissipation requirements can still be achieved.

Also as shown in Figure 9, the way of fixing the heat dissipation upper cover is extended with different possible installation conditions, which is the fourth preferred embodiment of the present invention. The turbulent flow heat dissipation upper cover body 3"' extends with a plurality of through holes On the side wing 904, a plurality of fixing holes 902 are formed on the circuit board, and the positions of the two holes correspond to each other; the fixing device is a plurality of bolts 906 passing through the through holes of the side wing and the fixing holes. , so that the circuit board 22 is closely combined with the turbulent heat dissipation upper cover body 3"'. Although the above-mentioned fixing methods are different, they all ensure the formation of turbulent flow space, so that the heat energy generated by the heating element can be carried out by the turbulent flow with the best efficiency, and the lower temperature air with a considerable temperature difference can be continuously supplied. Replace to cool heat generating parts.

The present invention ensures a large amount of convection and heat exchange between the gas molecules passed in by forming turbulent flow in the air duct, so that the temperature difference gradient between the gas at the bottom layer and the air duct is significantly improved, so the heat dissipation efficiency of the gas introduced is greatly improved; and The structure is simple, there is no need to worry about short-circuit risks such as liquid leakage during operation, and the manufacturing and operating costs are relatively low; especially when the heat dissipation efficiency is improved, the circuit designer can freely choose circuit components with higher power, and there is no need to worry about circuit instability caused by insufficient heat dissipation The problem is an important infrastructure to improve the performance of the overall electronic device, thereby solving all the technical problems that the present invention intends to solve.

The above preferred embodiments are only used to illustrate the present invention, but not to limit the present invention. Those skilled in the art can also make various modifications and transformations without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions belong to the protection scope of the present invention.

Claims (8)

1. the turbulent flow of corresponding heat generating member end face heat radiation loam cake, be used to connect a feeder with a scheduled volume air feed, and acceptance is from the air-flow of this feeder, derive the heat energy that this heat generating member is sent out, and this heat generating member is arranged on the circuit board, this heat radiation loam cake comprises a heat radiation loam cake body, and this body comprises:

One roof; And

One from this roof extension, be used to keep this roof and described heat generating member end face to keep a preset distance, and define the escapement in an air channel jointly with this roof and described heat generating member end face, described escapement comprises from the two side that described roof extends, an and diapire relative with described roof, and described diapire is formed with a corresponding described heat generating member end face sized opening

Described air channel makes from the described air-flow Reynolds number of described feeder

Re=(ρ umd)/μ 〉=2,500; Wherein, ρ is a current density; Um is an air velocity in the air channel;

D is a duct dimension; μ is the air-flow viscosity; And

A junction that connects this feeder to this air channel.

2. turbulent flow heat radiation loam cake according to claim 1 is characterized in that: comprise that also one is fixed to the fixture of described circuit board with described heat radiation loam cake body.

3. turbulent flow heat radiation loam cake according to claim 2 is characterized in that: be formed with a plurality of blocking slotted eyes on the described circuit board, and described fixture comprises:

One roughly coat described fixed cover body around part; And

One from should extend around part bottom, and the clamping piece of corresponding described blocking slotted eye respectively.

4. turbulent flow heat radiation loam cake according to claim 2 is characterized in that described fixture comprises:

One roughly coat described fixed cover body around part;

A plurality of warpage portions that should bend extension with an angle certainly around the part bottom; And

Be fixed on this circuit board, and the fastener of corresponding described warpage portion.

5. turbulent flow heat radiation loam cake according to claim 2, it is characterized in that: be formed with a plurality of fixing holes on the described circuit board, and described turbulent flow heat radiation loam cake body also is extended with a plurality of flanks that are formed with through hole, and described fixture is a plurality of bolts that pass described flank through hole and described fixing hole.

6. heat elimination assembly, being used to derives the heat energy that a heat generating member that is arranged at a circuit board is sent out, and described heat elimination assembly comprises:

The turbulent flow heat radiation loam cake of one corresponding described heat generating member end face, described heat radiation loam cake comprise a heat radiation loam cake body, and this body comprises:

One roof; And

One from this roof extension, be used to keep this roof and described heat generating member end face to keep a preset distance, and define the escapement in an air channel jointly with this roof and described heat generating member end face, described escapement comprises from the two side that described roof extends, reaches a diapire relative with described roof, and described diapire is formed with a corresponding described heat generating member end face sized opening;

A junction that connects this feeder to this air channel; And

One connects described air channel, and so that in the described air channel air-flow reynolds number Re=(ρ umd)/μ 〉=2,500 air feed give the feeder in this air channel;

Wherein, ρ is a current density; Um is an air velocity in the air channel; D is a duct dimension; μ is the air-flow viscosity.

7. heat elimination assembly according to claim 6 is characterized in that: described heat radiation loam cake comprises that also one is fixed to the fixture of described circuit board with described heat radiation loam cake body.

8. heat elimination assembly according to claim 6 is characterized in that: described feeder is a blower fan.

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