Cooling device

Abstract

Conventional cooling systems have a problem where, when multiple heat-generating elements are arranged along the direction of refrigerant flow, the cooling efficiency of the heat-generating elements located downstream decreases. [Solution] The cooling device 1 comprises a base B on which first and second heating elements H1 and H2 are arranged, three fins F1 to F3 protruding from the base B, and first and second flow paths P1 and P2 formed between the fins, with the first and second heating elements H1 and H2 arranged on the upstream and downstream sides of the refrigerant flow direction, respectively, and at least one of the first and second flow paths P1 and P2 is provided with a turbulence source 2 located upstream of the second heating element H2, and a turbulence amplification mechanism 3 located downstream of the turbulence source 2, thereby achieving uniform cooling performance for the heating elements H1 and H2 in a cooling device 1 having a structure in which multiple heating elements H1 and H2 are arranged in the direction of refrigerant flow.

Description

Technical Field

[0001] The present invention relates to a cooling device used for cooling heat-generating bodies such as semiconductors and capacitors that constitute a power conversion device or the like.

Background Art

[0002] As a conventional cooling device, for example, there is one described in Patent Document 1. Patent Document 1 describes a cooling device in which the direction of the main flow of a cooling medium flowing on the surface of a heat-generating body is regulated. A plasma actuator is disposed on the surface of the heat-generating body, and by causing the main flow of the cooling medium and the induced flow of the plasma actuator to intersect to generate a vortex flow, a highly efficient and compact cooling device is provided while keeping the pressure loss low.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described conventional cooling device, in the case of a structure in which a plurality of heat-generating bodies are arranged along the flow direction of the refrigerant, the temperature of the refrigerant rises due to the heat-generating body arranged on the upstream side in the flow direction, and there is a problem that the cooling efficiency of the heat-generating body arranged on the downstream side decreases. Solving such a problem has been an issue.

[0005] The present invention has been made in view of the above-described conventional situation, and is a cooling device having a structure in which a plurality of heat-generating bodies are arranged along the flow direction of a refrigerant, and an object thereof is to provide a cooling device capable of realizing uniform cooling performance for each heat-generating body.

Means for Solving the Problems

[0006] The cooling device according to the present invention comprises a base on which first and second heating elements are arranged on one main surface, at least three fins protruding from the other main surface of the base, and first and second flow paths formed between adjacent fins and allowing refrigerant to flow in one direction, and the first and second heating elements are arranged on the upstream and downstream sides, respectively, in the direction of refrigerant flow. Furthermore, the cooling device is characterized in that at least one of the first and second flow paths is provided with a turbulence source arranged upstream of the second heating element and causing turbulence in the flow of refrigerant, and a turbulence amplification mechanism is provided downstream of the turbulence source for amplifying the turbulence generated by the turbulence source. [Effects of the Invention]

[0007] The cooling device according to the present invention generates turbulence in the flow of refrigerant using a turbulence source while refrigerant is flowing through the first and second flow paths, and further amplifies the turbulence downstream using a turbulence amplification mechanism. In other words, the cooling device cools a first heat-generating element located upstream of the refrigerant with the refrigerant introduced into the first and second flow paths, and downstream thereof, the turbulence source and turbulence amplification mechanism disturb the flow of the refrigerant to cause pulsation, thereby peeling off the boundary layer that hinders cooling performance and cooling a second heat-generating element located downstream of the refrigerant.

[0008] In this way, the above-described cooling device, having a structure in which multiple heat-generating elements are arranged along the direction of refrigerant flow, can achieve uniform cooling performance for each heat-generating element. [Brief explanation of the drawing]

[0009] [Figure 1] Figure (A) is a perspective view of the main part of the cooling device in the first embodiment, and Figure (B) is an explanatory diagram showing the plan view of the cooling device and a vertical cross-section based on line AA in Figure A, above and below. [Figure 2] This is an explanatory diagram showing the plan view and vertical cross-section of the cooling device in the second embodiment, above and below. [Figure 3] This is an explanatory diagram showing the plan view and vertical cross-section of the cooling device in the third embodiment, above and below. [Figure 4] This is an explanatory diagram showing the plan view and vertical cross-section of the cooling device in the fourth embodiment, above and below. [Figure 5] This is an explanatory diagram showing, above and below, a plan view and a vertical cross-section with an enlarged view of the cooling device in the fifth embodiment. [Figure 6] These are explanatory diagrams (A) and (B) respectively, showing the plan and vertical cross-section of the cooling device in the sixth embodiment of the cooling device. [Modes for carrying out the invention]

[0010] <First Embodiment> The cooling device 1 shown in Figure 1 comprises a base B on which first and second heating elements H1 and H2 are arranged on one main surface, at least three fins F1, F2, and F3 protruding parallel to each other from the other main surface of the base B, and first and second flow paths P1 and P2 formed between adjacent fins F1 to F3 and allowing refrigerant to flow in one direction. The heating elements H1 and H2 are not particularly limited, but examples include semiconductors and capacitors that constitute a power conversion device. These heating elements H1 and H2 are thermally connected to the base B.

[0011] In Figure 1, the cooling device 1 is positioned with the base B vertical and the fins F1 to F3 horizontal, but it is not limited to this position. Furthermore, in the following description, the three fins F1 to F3 are referred to as the upper fin F1, the central fin F2, and the lower fin F3, with a first flow path P1 formed between the upper fin F1 and the central fin F2, and a second flow path P2 formed between the central fin F2 and the lower fin F3.

[0012] The cooling device 1 described above has a structure in which the first and second heating elements H1 and H2 are arranged on the upstream and downstream sides, respectively, of the refrigerant flow direction indicated by the thick arrows in Figure 1(B). The first and second heating elements H1 and H2 are sized to span both the first and second flow paths P11 and P2, as shown by the dotted lines in the lower part of Figure 1(B). In this embodiment, gas or liquid can be used as the refrigerant.

[0013] Furthermore, the cooling device 1 described above includes a turbulence source 2 located upstream of the second heat-generating element H2 and causing turbulence in the refrigerant flow in at least one of the first and second flow paths P1 and P2, and a turbulence amplification mechanism 3 located downstream of the turbulence source 2 for amplifying the turbulence generated by the turbulence source 2. In Figure 1(B), the left vertical dotted line S1 is the location of the upstream end of the turbulence source 2, and the right vertical dotted line S2 is the location of the upstream end of the second heat-generating element H2. The arrows pointing from vertical dotted line S2 to vertical dotted line S1 indicate that the turbulence source 2 is located upstream of the second heat-generating element H2.

[0014] In this embodiment, the turbulence source 2 is provided on the central fin F2 that separates the first flow path P1 and the second flow path P2, and generates turbulence (arrow T) in the refrigerant in both the first and second flow paths P1 and P2. The turbulence source 2 is not particularly limited as long as it has the function of generating turbulence in a unidirectional flowing refrigerant, but for example, a fixed object protruding into the refrigerant flow or equipment that generates flow by contact can be used.

[0015] Furthermore, the turbulence amplification mechanism 3 in this embodiment is provided on both sides of the central fin F2, continuously downstream of the turbulence source 2. The turbulence amplification mechanism 3 is not particularly limited as long as it amplifies the turbulence generated by the turbulence source 2, but for example, it can employ an uneven surface consisting of protrusions and grooves that intersect in the direction of refrigerant flow, or an uneven surface with dimple-shaped recesses or embossed protrusions arranged vertically and horizontally.

[0016] The cooling device having the above configuration causes turbulence (arrow T) in the refrigerant flow by the turbulence generation source 2 while the refrigerant is flowing through the first and second flow paths P1 and P2, and amplifies the turbulence by the turbulence amplification mechanism 3 on the downstream side thereof. That is, the refrigerant flow becomes amplified turbulence as shown by the thin arrows. That is, the cooling device cools the first heating element H1 disposed on the upstream side of the refrigerant with the refrigerant introduced into the first and second flow paths P1 and P2, and on the downstream side thereof, the turbulence generation source 2 and the turbulence amplification mechanism 3 disturb the refrigerant flow so as to pulsate, peel off the boundary layer that hinders the cooling performance, and cool the second heating element H2 disposed on the downstream side of the refrigerant.

[0017] In this way, the above-described cooling device 1 can achieve uniformization of the cooling performance for each of the heating elements H1 and H2 in a cooling device having a structure in which a plurality of heating elements H1 and H2 are arranged along the refrigerant flow direction.

[0018] FIGS. 2 to 7 are diagrams for explaining the second to seventh embodiments of the cooling device according to the present invention. In the following embodiments, the same reference numerals are given to the same components as those in the first embodiment (FIG. 1), and detailed descriptions thereof are omitted.

[0019] <Second Embodiment> The cooling device 1 shown in FIG. 2 has the same basic configuration as that of the first embodiment, and the turbulence generation source 2 is a plasma actuator disposed on the lower fin F3, and the turbulence amplification mechanism 3 is a mechanism that amplifies turbulence between the first flow path P1 and the second flow path P2. Therefore, the refrigerant in this embodiment is a gas, typically air.

[0020] Although detailed illustration of the plasma actuator (2) is omitted, it includes a first electrode provided on the surface of a dielectric and a second electrode provided inside the dielectric. The plasma actuator generates plasma from both sides of the exposed electrode by applying an alternating voltage to both electrodes, and generates an induced air flow along the surface of the dielectric. That is, the turbulence generation source 2 in the illustrated example generates turbulence (arrow T) by interfering with the refrigerant flow with the induced air flow.

[0021] Furthermore, the turbulence amplification mechanism 3 in the illustrated example consists of multiple communication holes 3A that pass through the central fin F2 separating the first flow path P1 and the second flow path P2, thereby connecting the first flow path P1 and the second flow path P2. In the illustrated example, the communication holes 3A are arranged at predetermined intervals in the central fin F2, both vertically and horizontally.

[0022] In the cooling device 1 with the above configuration, while refrigerant is flowing through the first and second flow paths P1 and P2, a turbulence source 2 generates turbulence (arrow T) in the refrigerant flow, and downstream thereafter, a turbulence amplification mechanism 3 amplifies the turbulence. At this time, since the cooling device 1 uses a plasma actuator as the turbulence source 2, it can effectively generate air pulsations that separate the boundary layer.

[0023] Furthermore, the cooling device 1 described above employs a configuration in which a turbulence amplification mechanism 3 amplifies turbulence between the first flow path P1 and the second flow path P2, and is equipped with multiple communication holes 3A. As a result, the cooling device 1 allows refrigerant to flow in and out between the first flow path P1 and the second flow path P2 through the communication holes 3A, causing the refrigerant to pulsate and become turbulent in each flow path P1 and P2, and the pulsation becomes larger as it moves downstream.

[0024] The above-described cooling device 1 can achieve the same effects as the first embodiment, and by employing a plasma actuator as the turbulence source 2 and a turbulence amplification mechanism 3 equipped with a communication hole 3A, it further improves the turbulence generation and amplification functions, as well as the boundary layer separation function that hinders cooling performance. This allows for good cooling performance to be maintained even downstream of each flow path P1 and P2, resulting in uniform cooling performance overall. Furthermore, because the above-described cooling device 1 uses a turbulence amplification mechanism 3 equipped with a communication hole 3A, it can be formed using a relatively simple and inexpensive manufacturing method, resulting in excellent productivity.

[0025] <Third Embodiment> The cooling device 1 shown in Figure 3 has the same basic configuration as the second embodiment, and the turbulence source 2 is provided with at least one communication hole 2A that penetrates the central fin F2 separating the first flow path P1 and the second flow path P2, thereby connecting the first flow path P1 and the second flow path P2. In the illustrated example of the cooling device 1, the turbulence source 2 is configured such that a plurality of communication holes 2A are arranged vertically and horizontally within a predetermined range.

[0026] The cooling device 1 described above can achieve the same turbulence generation effect as the second embodiment by using a turbulence source 2 equipped with a communication hole 2A, and a turbulence amplification mechanism 3 equipped with another communication hole 3A downstream thereof further improves the boundary layer separation function that hinders cooling performance, thereby maintaining good cooling performance downstream of each flow path P1, P2 and achieving overall uniform cooling performance. Furthermore, since the cooling device 1 shown in the example has a configuration in which both the turbulence source 2 and the turbulence amplification mechanism 3 are equipped with communication holes 2A and 3A, it can be formed using a relatively simple and inexpensive manufacturing method, resulting in excellent productivity.

[0027] In the cooling device 1 described above, refrigerant was circulated through the first and second flow paths P1 and P2, turbulence was generated, and the turbulence was amplified to analyze the temperature distribution. As a result, it was found that in the turbulence amplification means 3, the surface integral Nusselt number on the upstream side was 2 and 7, and the Nusselt number on the downstream side was 4 and 8, indicating an improvement in the heat transfer capacity on the downstream side. This confirmed that uniform cooling performance was achieved.

[0028] <Fourth Embodiment> The cooling device 1 shown in Figure 4 includes a turbulence source 2 with a projection 2B formed on a central fin F2 that separates the first flow path P1 and the second flow path P2. The projection 2B in the illustrated example may be a separate component from the central fin F2, or it may be integrally molded with the central fin F2, and it protrudes toward both the first flow path P1 and the second flow path P2. Furthermore, the turbulence amplification mechanism 3 can employ, for example, the configuration described in the first to third embodiments.

[0029] The above-described cooling device 1, in particular, can obtain a turbulence generation effect similar to that of the second embodiment by using a turbulence source 2 equipped with protrusions 2B, and can maintain good cooling performance downstream of each flow path P1, P2, thereby achieving uniform cooling performance overall. Furthermore, by employing a turbulence source 2 equipped with protrusions 2B, the above-described cooling device 1 can be formed using a relatively simple and inexpensive manufacturing method, resulting in excellent productivity.

[0030] <Fifth Embodiment> The cooling device 1 shown in Figure 5 comprises a turbulence source 2 with a communication hole 2A and a turbulence amplification mechanism 3 with a circular communication hole 3A. As shown in the enlarged view in Figure 5, the opening dimension (opening diameter) R of the communication hole 3A in the turbulence amplification mechanism 3 is larger than the spacing L between adjacent communication holes 3A, 3A.

[0031] The above-described cooling device 1 can improve cooling performance by promoting turbulence amplification through making the opening dimension (opening diameter) R of the communication hole 3A larger than the spacing dimension L between the communication holes 3A, 3A, and can achieve overall uniformity of cooling performance.

[0032] <Sixth Embodiment> In the cooling device 1 shown in Figure 6(A), the distance between the first heat-generating element H1 and the second heat-generating element H2 is smaller compared to other embodiments, the turbulence source 2 is positioned upstream of the first and second heat-generating elements H1 and H2, and the turbulence amplification mechanism 3 is positioned downstream of it.

[0033] The cooling device 1 described above can generate pulsations in the refrigerant flow even directly beneath the first heat-generating element H1, thereby separating the boundary layer, and can therefore handle cases where the heat generated by the first heat-generating element H1 is large.

[0034] <Seventh Embodiment> In the cooling device 1 shown in Figure 6(B), the distance between the first heat-generating element H1 and the second heat-generating element H2 is larger compared to other embodiments, the turbulence generation source 2 is placed between the first heat-generating element H1 and the second heat-generating element H2, and the turbulence amplification mechanism 3 is placed downstream of it.

[0035] The cooling device 1 described above is effective when the heat generated by the first heat-generating element H1 is not very large and it is desirable to actively cool the second heat-generating element H2. This indicates that even when the heat generated by the second heat-generating element H2 is greater than that generated by the first heat-generating element H1, uniform cooling performance can be achieved.

[0036] The cooling devices 1 of the sixth and seventh embodiments shown in Figure 6 have the same basic configuration as the first embodiment, and define the relative positions of the turbulence source 2, the turbulence amplification mechanism 3, the first heat-generating element H1, and the second heat-generating element H2. In other words, the cooling devices according to the present invention can all exhibit the same effect if the turbulence source 2 is positioned upstream of the second heat-generating element H2, and by adjusting the arrangement of each component while satisfying this condition, it becomes possible to design a device to meet specific requirements.

[0037] Furthermore, the cooling device 1 described above can employ a configuration in which the heat output of the second heat-generating element H2 is greater than that of the first heat-generating element H1. This configuration can also be applied to the first to fifth embodiments described above. As a result, the cooling device 1 can efficiently cool the first and second heat-generating elements H1 and H2, and achieve uniform cooling performance overall.

[0038] The cooling device according to the present invention is not limited to the above embodiments, and its configuration can be modified as appropriate without departing from the spirit of the present invention. For example, the number and arrangement of turbulence sources, the range and arrangement of the turbulence amplification mechanism 3, etc., can be changed as appropriate, and it is also possible to combine the specific configurations described in the above embodiments. [Explanation of symbols]

[0039] 1 Cooling device 2. Turbulence Sources 2A Communication holes for turbulence source 2B Protrusions of turbulence sources 3. Turbulence Amplification Mechanism 3A Communication hole for turbulence amplification mechanism B Bass F1 Upper Fin F2 Center Fin F3 lower fin H1 First heating element H2 Second heating element P1 First channel P2 Second channel

Claims

1. The device comprises a base on which first and second heating elements are arranged on one main surface, at least three fins protruding from the other main surface of the base, and first and second flow paths formed between adjacent fins and allowing refrigerant to flow in one direction, with the first and second heating elements arranged on the upstream and downstream sides, respectively, in the direction of refrigerant flow. At least one of the first and second flow paths is provided with a turbulence source located upstream of the second heating element and which causes the flow of the refrigerant to become turbulent. A cooling device characterized by having a turbulence amplification mechanism downstream of the turbulence source that amplifies the turbulence generated by the turbulence source.

2. The cooling device according to claim 1, characterized in that the turbulence amplification mechanism is a mechanism for amplifying turbulence between the first flow channel and the second flow channel.

3. The cooling device according to claim 2, characterized in that the turbulence source is a plasma actuator.

4. The cooling device according to claim 2, characterized in that the turbulence source has at least one communication hole that penetrates a central fin separating the first flow path and the second flow path and connects the first flow path and the second flow path.

5. The cooling device according to claim 2, characterized in that the turbulence source is provided with a projection formed on a central fin that separates the first flow path and the second flow path.

6. The cooling device according to claim 2, characterized in that the turbulence amplification mechanism has a plurality of communication holes that pass through a central fin separating the first flow path and the second flow path and connect the first flow path and the second flow path.

7. The cooling device according to claim 6, characterized in that the opening dimensions of the communication holes in the turbulence amplification mechanism are larger than the spacing between the communication holes.

8. A cooling device according to any one of claims 1 to 7, characterized in that the heat output of the second heating element is greater than the heat output of the first heating element.

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