RU2634167C1 - Radiator - Google Patents

Abstract

FIELD: machine engineering.

SUBSTANCE: radiator is described, made of thermally conductive material containing a heat absorbing surface in contact with the heat-generating surface of the electronic component and a heat-distributing surface. The heat-distributing surface is parallel ribs that are perpendicular to the heat absorbing surface of the radiator. The ribs form channels for the passage of cooling medium. Each channel wall alternates with flat and concave surfaces in such a way that the cross section of the channel changes along the whole path of cooling medium movement.

EFFECT: intensification of heat transfer from the radiator to the cooling medium.

6 cl, 8 dwg

Description

The invention relates to the field of heat engineering and can be used for cooling heat-loaded elements of electronic components, power and switching devices, transistor modules, electrical appliances.

Known radiator (patent CN 101072481, IPC G12B 15/06, G06F 1/20, H05K 7/20, H01L 23/367, published November 14, 2007) made of an aluminum alloy and containing a heat-absorbing surface in contact with the heat-generating surface of the electronic component, and a heat-distributing surface formed perpendicular to the heat-absorbing surface by parallel ribs creating channels for the passage of the cooling medium. Fins of a constant profile in a section perpendicular to the direction of passage of the cooling medium. A disadvantage of the known radiator is the low heat transfer from the fins to the cooling medium due to the presence of a poorly destructible thermal boundary layer. A thermal boundary layer is formed upon the flow of any solid body with a liquid or gaseous medium that differs from it in temperature on its surface due to the action of viscosity and temperature gradient.

The radiator is devoid of this drawback (patent CN 202026556, IPC G06F 1/20, H05K 7/20, H01L 23/367, published 02.11.2011), containing many parallel identical ribs in the form of plates. The cooling medium moves perpendicular to the ribs, and in the zone of passage of the cooling medium on the end surface of each rib there are many protrusions and depressions. Neighboring ribs are offset relative to each other so that in the direction of movement of the cooling medium behind the protrusion of the next ribs follows the depression of the next and so on. In this case, the destruction of the thermal boundary layer occurs, the heat transfer from the ribs to the cooling medium increases, but the hydraulic resistance of the radiator to the flow of the cooling medium increases significantly, which requires the use of powerful pressure equipment to supply the cooling medium.

A known radiator (patent CN 104807362, IPC F28F 13/12, F28F 3/02, published July 29, 2015) with fins containing elements of a V-shaped structure arranged in a checkerboard pattern. With this design of the radiator, a good destruction of the thermal boundary layer occurs, but the hydraulic resistance to the flow of the cooling medium is large. It is very difficult to make such a radiator using machining or plastic deformation methods.

The closest in technical essence and the set of essential features to the claimed technical solution is the radiator adopted for the prototype (patent CN 202614072, IPC F28F 13/12, H01F 27/12, published December 19, 2012) with fins made of a curved metal strip in in the form of a "snake", and each vertex of the curved tape is opposite the hollow of the adjacent curved tape. To pass the cooling medium, the tapes are located at a small distance from each other, forming a through channel of constant cross section. The cooling medium, passing through the channels formed by ribbons, constantly changes the direction of movement in a zigzag fashion. With this arrangement of the fins, the radiator has a slight increase in hydraulic resistance to the flow of the cooling medium compared to the direct-flow channels, but significantly less in comparison with analogues with offset and V-shaped fins. During turbulent movement of the flow of the cooling medium, due to the constant change in its direction, the thermal boundary layer is destroyed. The disadvantage of this technical solution is the poor destruction of the thermal boundary layer during laminar motion of the flow of the cooling medium. This is especially true for viscous cooling media. In addition, the proposed technical solution provides for the manufacture of fins from sheet metal material and their connection with the heat-absorbing surface of the radiator by spot welding. With this connection, there will be low heat transfer from the ribs to the heat-absorbing surface, which will degrade the operation of the radiator.

The technical result that can be obtained by carrying out the invention is to increase the heat transfer from the radiator to the cooling medium due to the destruction of the thermal boundary layer of the flow of the cooling medium.

The problem to which the invention is directed, is to obtain a radiator for cooling heat-loaded elements of electronic components, power and switching devices, transistor modules, electrical appliances, highly efficient due to the destruction of the thermal boundary layer of the flow of the cooling medium, small-sized, with low hydraulic resistance and the possibility of its manufacture simple machining methods.

SUMMARY OF THE INVENTION A radiator made of a heat-conducting material, comprising a heat-absorbing surface in contact with a heat-generating surface of an electronic component, and a heat-distributing surface formed perpendicular to the heat-absorbing surface by parallel ribs creating channels for the passage of a gaseous or liquid cooling medium, is that each wall the channel is formed by alternating flat and concave surfaces so that the cross section of the channel changes elk on the entire displacement path of the cooling medium.

The solution to the problem is promoted by the signs characterizing the invention in particular cases of its implementation or use.

Concave surface of the channel wall may have the configuration of a body of revolution.

The heat-absorbing and heat-distributing surfaces of the radiator can be made of different materials. Moreover, the connection between the heat-absorbing and heat-distributing surfaces can be, for example, soldering or pressing under high pressure.

The edges of the heat-distributing surface may not be perpendicular to the heat-absorbing surface.

The radiator channels can be covered with a lid to direct the flow of the cooling medium in order to improve heat transfer from the radiator to the cooling medium.

The technical solution with the claimed combination of essential features of an independent claim is not known from the prior art, which confirms its compliance with the patentability condition “novelty”.

The essential features of the independent claim of the claimed invention for a specialist do not explicitly follow from the prior art, which confirms the compliance of the invention with the condition of patentability "inventive step".

The invention is confirmed by drawings, where:

in FIG. 1 - radiator, side view;

in FIG. 2 - radiator, top view;

in FIG. 3 - radiator, section AA;

in FIG. 4 - radiator, section BB;

in FIG. 5 - radiator, side view (option);

in FIG. 6 - a cover;

in FIG. 7 - radiator with installed cover;

in FIG. 8 - radiator with fins not perpendicular to the heat-absorbing surface, side view.

The list of positions of the elements of the drawings of the radiator:

1 - heat-absorbing surface;

2 - heat distribution surface;

3 - rib;

4 - channel;

5 - projection of a flat surface of the channel;

6 - projection of the concave surface of the channel;

7 - hole;

8 - cooling medium;

9 - pointed protrusion;

10 - groove;

11 - ledge;

12 - guide channel;

13 - confuser;

14 - diffuser;

15 - a radiator;

16 - cover.

In the side view of the radiator (Fig. 1), a heat-absorbing surface 1 in contact with a heat-generating surface of an electronic component (not shown), a heat-distributing surface 2 in the form of a plurality of fins 3, forming channels 4 for passage of a cooling medium are shown.

The top view of the radiator (Fig. 2) shows the alternation of flat 5 and concave 6 (special case: body of revolution - circle) projections of the channel surfaces.

Section AA radiator (Fig. 3) allows you to understand the method of its manufacture. In a metal billet of heat-conducting metal (for example, copper), holes 7 with a diameter d of depth h are drilled in a checkerboard pattern, and then grooves of width b and depth h are milled (Fig. 1). The same configuration of the radiator fins, but with concave surfaces of the fins, not in the form of a circle, can also be obtained by machining on numerically controlled metal-cutting equipment. The diameter of the holes, the width of the grooves and their depth are selected empirically depending on the used cooling medium (gaseous, liquid medium; parameters of its viscosity, heat capacity, thermal conductivity), type of flow of the cooling medium (turbulent, intermediate, laminar), parameters of the heat-generating surface of the electronic component ( heat output, configuration, dimensions), radiator material. The dimensions of the radiator are determined by the dimensions of the heat-generating surface of the electronic component and the general layout of the product where the radiator is used.

The cross section BB of the radiator (Fig. 4) allows us to understand the method of destruction of the thermal boundary layer in the radiator. When any solid body flows around a liquid or gaseous medium that differs from it in temperature, a region called a thermal boundary layer is formed on its surface due to the action of viscosity forces and a temperature gradient. The temperature change of the near-wall flow of the medium occurs at a very small distance from the wall within the given layer. The outflow of the medium in the zone of the thermal boundary layer is, as a rule, laminar. The heat transfer process in the laminar boundary layer is carried out by thermal conductivity. The thinner the layer and the higher the thermal conductivity of the medium, the better the heat transfer. An even greater effect is achieved with the constant destruction of the thermal boundary layer and the replacement of the heated layer with a cold one, i.e. creating flow turbulence. The more places there are collisions of a jet with a solid surface, the more places with local turbulence and a maximum heat transfer coefficient. In the present invention, this is achieved by the special configuration of the channel 4 of the movement of the cooling medium 8: the presence of pointed protrusions 9 on the surface of the ribs 3 at the junction of the flat and concave surfaces of the walls of the channel and a constantly changing cross section of the channel along the entire path of movement of the cooling medium. In this case, chaotic swirling of the coolant flow occurs along the entire path of its movement in the radiator and the destruction of its thermal boundary layer. In connection with the destruction of the thermal boundary layer of the cooling medium, there is an increase in heat transfer from the radiator to the cooling medium. In this case, the minimum cross-section of the channel cannot be less than the width b (Fig. 1) of the forming tool used in the manufacture of the radiator, which guarantees the radiator minimal hydraulic resistance.

The heat-absorbing and heat-distributing surfaces of the radiator can be made of different materials (for example, copper, aluminum, composite materials). The connection between the heat-absorbing and heat-distributing surfaces in this case can be carried out, for example, by soldering, pressing under high pressure, welding, casting.

The embodiment of the radiator with two grooves 10 (Fig. 5) for attaching the cover allows you to direct the entire flow of the cooling medium through the channels 4 of the radiator when using the cover. This is achieved by installing in the grooves 10 of the protrusions 11 of the cover (Fig. 6), made of plastic. The cover has a guide channel 12, a confuser 13, a diffuser 14 to form a uniform flow of cooling medium into the radiator and reduce its hydraulic resistance.

In FIG. 7 shows a radiator 15 with a cover 16 installed.

In FIG. 8 shows a radiator (side view) with fins not perpendicular to the heat-absorbing surface.

The radiator works as follows. The heat-absorbing surface 1 of the radiator 15 is installed on the heat-generating surface of the electronic component (it is possible through the thermal interface). The heat flux from the heat-generating surface of the electronic component through the heat-absorbing surface of the radiator is transferred by heat conduction to its heat-distributing surface 2. Through channels 4 of the heat-distributing surface of the radiator, a cooling medium 8 (gaseous or liquid) is supplied. Due to the presence of pointed protrusions 9 on the surface of the ribs 3 at the junction of the flat and concave surfaces of the channel walls and a constantly changing cross section of the channel along the entire path of movement of the cooling medium, chaotic swirling of the flow of the cooling medium in the radiator occurs and its thermal boundary layer is destroyed. In connection with the destruction of the thermal boundary layer of the cooling medium, intense heat transfer from the radiator to the cooling medium occurs. To direct the entire flow of cooling medium through the channels, a cover 16 is installed on the radiator.

The described means and methods by which it is possible to carry out the invention, with the implementation of the indicated purpose confirm the compliance of the invention with the condition of patentability "industrial applicability"

Claims (6)

1. A radiator made of a heat-conducting material, containing a heat-absorbing surface in contact with the heat-generating surface of the electronic component, and a heat-distributing surface formed perpendicular to the heat-absorbing surface by parallel ribs creating channels for the passage of a gaseous or liquid cooling medium, characterized in that each channel wall is formed alternating flat and concave surfaces so that the cross section of the channel changes all the way movement of the cooling medium. 2. The radiator according to claim 1, characterized in that the concave surface of the channel wall has the configuration of a body of revolution. 3. The radiator according to claim 1, characterized in that the heat-absorbing and heat-distributing surfaces are made of different materials. 4. The radiator according to claim 2, characterized in that the heat-absorbing and heat-distributing surfaces are made of different materials. 5. Radiator according to any one of paragraphs. 1-4, characterized in that the ribs of the heat-distributing surface are not perpendicular to the heat-absorbing surface. 6. Radiator according to any one of paragraphs. 1-5, characterized in that the channels are closed by a lid to direct the flow of the cooling medium.

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