CN105453257A - Enhanced structure for natural cooling heat sink - Google Patents

Abstract

The present invention relates to a heat sink for instance for use in a remote radio unit comprising a plurality of fins (8, 9, 10) arranged such that channels (11, 12, 13) are formed between adjacent fins, said channels (11, 12, 13) comprising an air inflow and an air outflow, wherein the heat sink comprises at least two groups (5, 6, 7) of fins (8, 9, 10) arranged such that the air inflow of the channels of a first of said groups (5) is located differently from the air outflow of the channels of the remaining of said groups (6, 7). The invention furthermore relates to a method of cooling a heat- generating device, such as a remote radio unit, the method comprising providing at least two groups of air flow channels in thermal contact with said heat- generating device, each channel having an air inflow region and an air outflow region, wherein the air inflow regions of the channels of the first group are located differently from the air outflow regions of the channels of the remaining groups, such that hot air leaving through the air outflow regions of said remaining groups is prevented from entering the channels of the first group through the respective air inflow regions of the first group.

Description

Reinforced structure for free cooling radiator

The present invention generally relates to a heat sink for cooling electronic equipment such as a remote radio unit (RRU), and more specifically, to a heat sink for obtaining a cooling effect through natural convection.

Background technique

Compared with transmission base stations, distributed base stations have obvious advantages, such as easy installation, operation and maintenance. At the same time, operators want high output power, light weight, small size, etc., which lead to high heat density of RRU. The RRU is the main module of the distributed base station. Today, RRU heat consumption has risen from 200W to the current 300W, and RRU cooling is becoming more and more important and challenging.

The RRU is cooled by employing a heat sink and utilizing natural convection. A prior art RRU heatsink is shown in Figure 1 and mainly consists of straight fins which are optimized based on internal heat dissipation, heatsink height and its temperature to increase overall cooling capacity and achieve lower temperatures in the unit . The current optimization methods mentioned above cannot further improve the cooling capacity, some new design or technology must be applied to improve the cooling.

A standard way to increase the RRU cooling capacity is to expand the HS volume, as shown in Figure 2. Increased HS volume means higher fins and increased HS surface area, which is very important for heat dissipation.

Another existing technology for RRU cooling capacity is to apply fan cooling, as shown in Fig. 3 . The independent fan frame is fixed on the top of the RRU. As the main heat transfer mechanism changes from natural convection to forced convection, the cooling capacity of the RRU is improved.

There are a number of problems with prior art radiators. Therefore, in order to increase the cooling capacity of the RRU, one prior art solution is mentioned above to increase the cooling area, which results in an increase in the volume and weight of the RRU. The bulk increase does not serve the operator's purpose of degrading the overall appearance of the site. The added weight will result in higher requirements for installation on the tower or pole and result in higher costs. This prior art is not easily accepted by operators.

Another prior art solution is to add a separate fan frame. However, independent fans cannot effectively reduce the volume of the RRU. The independent fan frame will give the new appearance and volume of the RRU. In addition, the independent fan frame cannot meet the operator's requirements for a simple and uniform appearance. Additionally, the fan frame requires maintenance, which is difficult and expensive when the RRU is fixed to a wall, tower, or some other high location. Therefore, this prior art solution is also difficult to be accepted by operators

In a traditional radiator with straight fins, air flows through the air channels formed between the fins due to buoyancy, and the air is continuously heated as it flows from the bottom to the top. As a result, in the upper half of the RRU, the air temperature is higher, so the cooling capacity of the fins in this area is less.

Contents of the invention

Against this background, it is an object of the present invention to provide a heat sink which overcomes or at least alleviates the problems of the prior art.

In the enhanced heat sink structure according to the present invention, the length of the air passage formed between adjacent fins becomes shorter, thereby reducing the self-heating effect. According to the invention, the same radiator volume but higher cooling capacity is achieved.

According to the present invention, there is provided a radiator comprising a plurality of fins arranged such that a channel is formed between adjacent fins, wherein the channel includes an air inlet and an air outlet. The heat sink according to the invention comprises at least two sets of fins arranged such that the positions of the air inlets of the channels of the first set are different from those of the air outlets of the channels of the remaining sets. Thus, hot air from the air outlets of the group of channels located below the first group of channels is prevented from entering the channels of the first group of channels.

It should be noted that in this context, the term "air inlet" refers to the location or areas where air enters the heat sink structure from the surrounding environment, and similarly, the term "air outlet" refers to the place or areas where air exits the heat sink structure and exits to the surrounding environment. One or more locations or regions. These locations or areas are indicated by arrows in the detailed description of the present invention, but it should be understood that these representations are only exemplary and show some specific locations of inflow and outflow structures. Further, when the flow of hot air in the channel is driven by upward buoyancy, it should be understood that in this specification, the "first" group of fins or channels refers to the direction of air flow caused by the buoyancy of hot air. group in . Thus, for example, in the two embodiments respectively shown in FIGS. 4 and 5 , the respective longitudinal axis Y extends in an upward direction perpendicular to the ground.

According to an embodiment of the invention, the at least two sets of fins are arranged such that the longitudinal direction of the fins of the first set extends at an angle α with respect to the longitudinal direction of the fins of the second set, where α≠0 degrees.

Other objects, features, advantages and properties of the reinforced heat sink according to the present invention will appear clearly through the specific description.

Description of drawings

In the following detailed description of the present description, the invention will be explained in more detail with reference to exemplary embodiments shown in the accompanying drawings, in which:

Figure 1 is a first example of a prior art radiator;

Fig. 2 is a second example of a prior art heat sink, wherein the cooling effect is enhanced by increasing the height of the fins and the cooling area of the heat sink;

3 is a third example of a prior art heat sink in which enhanced cooling capacity is obtained by providing a fan that changes the heat transfer mechanism from natural convection to forced convection;

Figure 4 is a schematic representation of a heat fin structure according to a first embodiment of the invention; and

Figure 5 is a schematic representation of a heat fin structure according to a second embodiment of the present invention.

Detailed description of the preferred embodiment

Referring to Figure 1 , there is shown a prior art heat sink 1 comprising a portion of fins 2 of relatively low height. When the cooling capacity of this prior art radiator is found to be insufficient, the height of the fins can be increased, as shown in the prior art radiator according to FIG. 2 , thereby increasing the cooling area per fin.

Figure 3 shows an alternative to obtain increased cooling efficiency by increasing the height of the fins, where fan cooling is applied. One or more cooling fans 4 are placed on top of the RRU, and the cooling capacity is increased as the primary heat transfer mechanism is changed from natural convection (in Figures 1 and 2) to forced convection.

Referring to Figure 4, there is shown a schematic representation of a heat fin structure according to a first embodiment of the present invention. According to this embodiment, the heat sinks are divided into three groups 5, 6 and 7: the upper group 5, where the fins 8 are vertical (as shown), and the lower left group 6, where the fins 9 point obliquely Upper left, and group 7 at the lower right, with the fins 10 pointing obliquely to the upper right.

In the vicinity of the air volume indicated as air inlet 1 and air inlet 2, air flows from the front of the radiator 1 into the channel 11 formed by the adjacent fins 8, continues to flow along the vertical fins 8 where the air finally flows upwards, and then The accommodating space of the radiator flows out from the air outlet 1 and the air outlet 2 .

In addition, air flows into the lower left group 6 of the radiator from the front end near the air inlet 3 and the bottom near the air inlet 4 . The inclined fins 9 ensure that the heated air is discharged directly from the receiving space of the radiator (air outlet 3 and air outlet 4 ) without heating the upper part of the radiator.

In group 7 on the lower right of the heat sink, a symmetrical behavior is observed.

In the three groups 5, 6 and 7, the respective air passages 11, 12 and 13 are independent of each other, so that the airflows in these three groups are correspondingly decoupled.

Therefore, the radiator according to this embodiment of the invention is divided into three groups in which the air passages and airflows are independent from each other and the influence of the temperature sequence is reduced. The air temperature in the upper channel drops, increasing the overall cooling capacity of the HS by about 10%.

In this embodiment, the fins 9 in the second group 6 are inclined at an angle β to the longitudinal axis Y, and the direction of the fins 8 in the first group 5 is consistent with the direction of the Y axis. The fins 10 in the third group 7 are inclined at an angle α to the longitudinal axis Y. In the illustrated embodiment, the alpha and beta angles are substantially equal, but it will be appreciated that this is generally not the case and that asymmetric designs of heat sinks according to the invention are contemplated and within the scope of this description. Similarly, heat sinks according to the present invention may not be symmetrical about the Y axis, as shown in FIG. 4 .

The basic concept of the present invention can be implemented by various other embodiments than the one shown in FIG. 4 . Accordingly, an alternative embodiment is shown in FIG. 5 . In this embodiment, the heat sinks 1 are divided into two groups: an upper group 14 in which the fins 16 are vertical (as shown) and a lower group 15 in which the fins 18 are inclined at an angle γ to the Y axis. extending toward the upper right of the radiator. Alternatively, the fins 18 in the lower set 15 may flow obliquely to the upper left of the heat sink.

In the upper group 14, the air inlet 1 and the air inlet 2 supply air from the front of the radiator to the channel 17, while the vertical fins 16 direct the air upwards, and the hot air flows out through the air outlets 1 and 2.

In the lower group 15 the air flows through the channels 19 in the lower group 15 through the air inlet 3 on the left side of the radiator and the air inlet 4 at the bottom of the radiator. The inclined fins 18 ensure that the heated air from the lower part of the radiator is directed out of the receiving space of the radiator without reducing the cooling capacity of the upper part.

The respective air passages 17 and 19 of the two sets 14 and 15 are independent of each other so that the air flows in these two parts are independent of each other.

Although the teachings of the present application have been described in detail for purposes of illustration, it is to be understood that such detail is for that purpose only and that various modifications can be made by those skilled in the art without departing from the scope of the teachings of the present invention. Revise.

The term "comprising" used in the appended claims does not exclude other elements or steps. The term "a" or "an" as used in the appended claims does not exclude a plurality. A single processor or other unit may fulfill the functions of several means recited in the claims.

Claims (12)

1. A heat sink comprising a plurality of fins (8, 9, 10) arranged such that channels (11, 12, 13) are formed between adjacent fins, said channels (11, 12, 13) includes an air inlet and an air outlet, and is characterized in that the radiator includes at least two groups (5, 6, 7) of fins (8, 9, 10), and the two groups of fins are arranged such that the first The positions of the air inlets of the channels of the group (5) are different from the positions of the air outlets of the channels of the remaining groups (6, 7). 2. The radiator according to claim 1, characterized in that the fins are arranged such that the longitudinal direction of the fins (8) of the first group (5) is aligned with the longitudinal direction of the fins (8) of the second group (6) The longitudinal direction of the fins (9) extends at an angle β, wherein β≠0 degree. 3. The heat sink according to claim 1 or 2, characterized in that, the length of the fins (8) of the first group (5) increases with each fin (8) and the heat sink The vertical axis Y varies as a function of the distance. 4. The heat sink according to claim 1 or 2, characterized in that, the heat sink comprises three fins (8, 9, 10) of the groups (5, 6, 7), and the three fins (5, 6, 7) are arranged sets of fins such that said fins (8) of a first (5) said set extend substantially parallel to the longitudinal axis Y of said heat sink, said fins (9) of a second (6) said set extending at an angle β to the longitudinal axis Y of said heat sink and said fins (10) of a third (7) said set extending at an angle α to the longitudinal axis Y of said heat sink. 5. The heat sink of claim 4, wherein said angle alpha is substantially equal to said angle beta. 6. The heat sink of claim 4, wherein the alpha angle is different from the beta angle. 7. Radiator according to claim 4, 5 or 6, characterized in that 0°<α<90° and 0°<β<90°. 8. The radiator according to claim 1 or 2, characterized in that it comprises two said groups (14, 15) of fins (16, 18), said two groups of fins being arranged such that The first (14) said set of said fins (16) extends generally parallel to the longitudinal axis Y of said heat sink, and the second (15) said set of said fins (18) extends substantially parallel to said The longitudinal axis Y of the heat sink extends at an angle γ. 9. The radiator according to claim 8, characterized in that 0°<γ<90°. 10. A remote radio frequency unit having a heat sink as claimed in any one of the preceding claims 1 to 9. 11. The remote radio frequency unit according to claim 9, characterized in that, the radiator is arranged on the remote radio frequency unit so that when the remote radio frequency unit is in its working state, the first group (5) The fins are positioned vertically above the remaining set of (6,7) fins. 12. A method of cooling heat producing equipment (e.g., a remote radio frequency unit), comprising providing at least two sets of airflow channels in thermal contact with the heat producing equipment, each channel having an air inlet area and the air outlet area, wherein the position of the air inlet area of the first group of channels is different from that of the air outlet area of the remaining group of channels, so that through the remaining group of the Hot air exiting the air outlet area is prevented from entering the channels of the first group through the respective air inlet area of the first group.