JP2020035859A - Cooling device for multi-stage electronic apparatus - Google Patents

Abstract

To provide a cooling device for a multi-stage electronic apparatus which simultaneously achieves downsizing of the entire device and improvement in cooling efficiency by evenly distributing a cooling fluid to cooling channels of each stage of the electronic apparatus and making temperature rise of each stage of the electronic apparatus equal while keeping a size of a common header that branches and joins cooling air small.SOLUTION: The cooling device for a multi-stack electronic apparatus mounts in a branch header 4a a two-step bent inclined plate 40 whose inclination angle is changed in the middle so that a reduction rate of a flow path cross-sectional area of the branch header 4a per a parallel mounting pitch of an electronic device 1 is large in an upstream part of the branch header 4a and is small at a downstream portion of the branch header 4a.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cooling device for a multi-stage electronic device, and more particularly to a multi-stage electronic device capable of distributing cooling air introduced by a blower substantially equally to each stage of a multi-stage electronic device, and being small and efficiently cooling. Related to a cooling device.

[Conventional technology]
Electronic devices such as electronic calculators and broadcasting systems use high-temperature electronic components such as semiconductor devices, FETs (field effect transistors), CPUs (central processing units), and power amplifiers on circuit boards in order to improve performance and obtain high output. Electronic devices mounted at a high density are mounted in a form of being stacked in multiple stages in the height direction of the housing. This is a multi-stage electronic device.

  A conventional air-cooled electronic device is a multi-stage electronic device in which cooling air flows sent from a blower are successively branched, as in a storage case of a multi-stage electronic device described in Patent Document 1 below. After cooling into the electronic device and cooling the electronic device, the cooling air flows are sequentially merged and discharged.

  In the housing of Patent Document 1, a diagram in which electronic devices are stacked in four layers is shown. However, in a terrestrial digital television transmitter, a large number of transmitters with small output power are required to obtain a large power transmission output. The transmission output is increased by combining and outputting, and the number of stacked layers is 10 or more.

  In the electronic device having such a large number of layers, the cooling flow paths of the electronic devices are connected in parallel to the branch header and the merge header, and the cooling fluid is guided to each stage of the cooling flow path of the electronic device by the branch and merge to cool. I have.

  However, it is said that as the number of layers of the electronic device increases, the cooling flow rate of each stage becomes more uneven, and it is difficult to make the temperature uniform. Even if the heat value of the electronic devices is the same, and even if the inflow cooling flow temperature of each stage is the same, if the cooling flow rate does not flow uniformly to each stage of the electronic device, the temperature of the many stacked electronic devices will be uniform ( Not constant).

  For example, referring to the technical material “Fluid Resistance of Pipes and Ducts” edited by The Japan Society of Mechanical Engineers, Jan. 1979, Maruzen, Chapter 4, page 99, FIGS. 4 and 122, and FIG. As described in 1, when a plurality of branch pipes of the same size are arranged in parallel to perform a Z-shaped flow, the pressure difference between the inlet and outlet of the branch pipe flow becomes larger toward the downstream branch pipe, and the downstream branch pipe flow path increases. It is shown that the flow rate flowing through the air increases.

  To explain this phenomenon more physically, the fluid flowing through the branch header flows into the branch pipe flow path of each stage one after another, so that the flow rate flowing through the branch header decreases, so the fluid flow velocity decreases, The cooling fluid pressure in the branch header increases. Furthermore, the fluid pressure loss in the branch header from the total inlet of the branch header to the flow channel inlet of each branch pipe increases only slightly because the fluid pressure loss in the branch header decreases downstream as the flow rate decreases. do not do.

  On the other hand, when the fluid flowing into the branch pipes of each stage flows out to the merge header, the fluid flowing out of the upstream branch flow path pushes the fluid flowing out of the downstream branch pipe parallel flow path one after another, and the outflow fluid increases. Must flow to the total outlet of the merging header while the fluid velocity in the merging header increases one after another.

  Therefore, the pressure of the cooling fluid in the merge header is higher at the upstream side and decreases at the downstream side closer to the total discharge port. The fluid pressure loss in the merge header from the total inlet of the branch header to the branch pipe flow outlet of each stage to the general outlet of the merge header is larger toward the upstream side, and rapidly decreases toward the downstream side toward the total discharge port.

  Therefore, the pressure difference between the entrance and exit of the branch pipe flow path at each stage increases with the pressure of the cooling fluid in the branch header and the pressure decrease of the cooling fluid in the junction header, and the pressure difference increases toward the downstream. The flowing cooling flow rate has a characteristic that it increases as it goes downstream.

[First Conventional Device (Comparative Example 1): FIG. 13]
Therefore, when a cooling fluid flows through a cooling flow path of a multi-stage electronic device, the pressure loss caused by branching and merging and the airflow characteristics of each electronic device will be clarified in more detail by flow simulation. Therefore, first, the configuration of the cooling channel of the conventional multi-stage electronic device will be described with reference to FIG. 13 (Comparative Example 1). Comparative Example 1 is a first conventional device. In the same figure, the arrows indicate the flow of the cooling air. FIG. 13 is an explanatory sectional view of a first conventional device.

  As shown in FIG. 13, the electronic devices 1 (PA1, PA2, PA3, PA4, PA5, PA6, PA7, PA8, PA9, PA10) are mounted in a stack of 10 stages in parallel. At this time, when the electronic devices 1 (PA1, PA2, PA3, PA4, PA5, PA6, PA7, PA8, PA9, PA10) are collectively referred to as the electronic device 1 (hereinafter abbreviated as PA), the same applies to 10 stages. The components of the configuration will not be numbered hereafter.

The cooling fins 2 are mounted in the lower layer of the PA, and the cooling channels 3 are configured. In the cooling passage 3 of the PA, the cooling fluid inlet 3a is connected to the branch header 4 via the branch introduction passage 6, and the cooling fluid outlet 3b is connected to the junction header 5 via the merge introduction passage 7. I have.
Then, the cooling air is cooled from the blower 20 in another housing (not shown) via the branch header 4 to cool each PA, and then exhausted from the merging header 5 to the outside of the housing 100.

  Regardless of the route where the cooling air flowing from the blower 20 flows to the PA at any position, the cooling air flowing through each route extends from the total entrance (point A) of the branch header 4 to the total exit (point B) of the merging header 5. In the flow simulation, the amount of cooling air passing through each PA and the pressure loss value generated at the junction of the cooling flow paths 3 and the like are determined by the flow principle such that the total pressure losses of all the cooling air flows are equal.

13 are stacked and mounted at a pitch of 100 mm, the branch header 4 and the merge header 5 both have a width of 100 mm and a depth of 650 mm, and the branch introduction flow path 6 and the merge introduction path 7 have a height of 36 mm and a long length. Is 40 mm. Then, a simulation of the flow was performed under a general condition that the total air flow rate was 30 m ³ / min.

[Pressure loss distribution at branching junction: FIG. 14 / air flow distribution of cooling fluid: FIG. 15]
The result is shown in FIG. In FIG. 14, the pressure loss ΔPhi in the branch header 4 from the total inlet (point A) of the branch header 4 to the cooling fluid inlet 3a of each PA 1, the pressure loss ΔPbi in the branch introduction flow path 6, and the pressure loss in the merge introduction path 7. ΔPbo, pressure loss ΔPho in the junction header 5 from the cooling fluid outlet 3b of each PA to the total exit (point B) of the junction header 5 and the like are shown for each PA stage as a pressure loss distribution generated at the branching junction of the cooling flow path. ing. The pressure loss in the cooling passage in the PA is not shown. FIG. 15 shows an air volume distribution of the cooling fluid passing through the cooling flow path in the PA.

  From the results shown in FIGS. 14 and 15, the sum of the pressure losses (ΔPhi + ΔPbi + ΔPbo + ΔPho) is largest in the lowermost stage PA10, smallest in the uppermost stage PA1, and conversely, the airflow is smallest in the lowermost stage PA10 and largest in the uppermost stage PA1. It can be seen that the deviation from the average airflow (indicated by the dashed line) is greatly deviated from + 23% to -12%.

  As shown in the above simulation, in the conventional cooling channel structure in which the branch headers 4 and the junction headers 5 of limited size are mounted in a stacked manner, the amount of cooling air flowing to the PA in each stage is made uniform. Was difficult.

[Second Conventional Device (Comparative Example 2): FIG. 16]
On the other hand, as shown in Patent Document 2, in order to control the flow in the branch header 4 and the merge header 5, the side walls of the branch header 4 and the merge header 5 are inclined, and the parallel cooling flow paths of the PA mounted in a stack are mounted. There is a idea to make the amount of cooling air flowing into the air uniform.
For example, an example of the structure disclosed in Patent Document 2 is shown in FIG. 16 as a second conventional device (Comparative Example 2). FIG. 16 is an explanatory sectional view of a second conventional device.
The structure of the second conventional device (Comparative Example 2) is such that the side wall of the branch header 4c is inclined in the flow direction of the branch header 4c so that the flow path cross-sectional area decreases at a constant rate, while the side wall of the merge header 5c is The flow path is inclined so that the cross-sectional area of the flow path increases at a constant rate in the flow direction of the merge header 5c. The other structure is the same as that of FIG. 13 described above.

The inclination of the side wall of the branch header 4c is such that the gap between the inclined wall and the inlet of the branch introduction flow path 6 becomes smaller by 10 mm for each PA mounting pitch, and the inclination of the side wall of the merge header 5c is The width of the PA outlet, which is the gap between the wall and the outlet of the merging introduction channel 7, has an inclination angle that increases by 5 mm for each PA mounting pitch.
However, the maximum width of the branch header 4c and the merging header 5c is the same as 100 mm, and the other conditions are the same as the above-described step-and-stack mounting conditions. The pressure loss generated at the junction of the roads was determined.

[Pressure loss distribution at branch junction: FIG. 17, cooling air flow distribution: FIG. 18]
The results of the simulation are shown in FIGS. The pressure loss sum (ΔPhi + ΔPbi + ΔPbo + ΔPho) is almost the same as the pressure loss sum (FIG. 14) of the first conventional device (FIG. 13), and the passing air volume is also compared with FIG. 15 of the first conventional device (FIG. 13). It can be seen that the deviation from the average airflow is large, from + 20% to -17%, and is slightly improved.

  This is because the maximum width of the merging header 5c on the outlet side is as small as 100 mm. Therefore, a structure in which the maximum width of the merge header 5c was greatly increased to 200 mm, which is twice as large as the structure shown in FIG. 16 (Comparative Example 2), was examined as Comparative Example 3 (third conventional device). The cross-sectional structure of Comparative Example 3 is not shown because the merge header 5c has the same inclination angle and only the width of the merge header 5c is increased.

[Pressure loss distribution at branching junction in third conventional apparatus (Comparative Example 3): FIG. 19, air flow distribution of cooling fluid: FIG. 20]
When only the simulation results under the above conditions are displayed, as shown in FIGS. 19 and 20, the difference between the upper and lower stages of the pressure loss sum (ΔPhi + ΔPbi + ΔPbo + ΔPho) becomes small, and the drift rate falls within ± 1%. However, the width of the merging header 5c on the outlet side is twice as large as 200 mm, which is twice as large, and it is difficult to house the flow path structure of Comparative Example 3 in a small casing.
Furthermore, when storing the multi-stack electronic device in the housing, it must be mounted eccentrically with respect to the housing, and the design of the housing is deteriorated. However, there is a problem that the width of the housing is further increased.

[Fourth Conventional Device (Comparative Example 4): FIG. 21]
On the other hand, as an attempt to simultaneously satisfy the demand for realizing a small housing and equalizing the cooling air volume, as shown in Patent Document 3, a structure in which the cross-sectional area of the flow passage only decreases in the branch direction at a fixed rate only in the branch header is disclosed. Proposed. FIG. 21 (Comparative Example 4) shows a cooling channel structure simulated under the same conditions as above in accordance with this idea as a fourth conventional apparatus. In FIG. 21, the same components as those in FIGS. 13 and 16 are denoted by the same reference numerals, and description thereof will be omitted.

[Pressure loss distribution at branching junction: FIG. 22, distribution of air flow of cooling fluid: FIG. 23]
As a result, the width of the merging header 5 on the outlet side was set to be the same as the maximum width of the branch header 4c on the inlet side, and was suppressed to a small 100 mm width that entered the housing. As shown in the simulation results, as shown in FIGS. The sum of the pressure losses (ΔPhi + ΔPbi + ΔPbo + ΔPho) has a large difference between the upper and lower stages, and the drift ratio is + 16% to −9%, which is slightly smaller than the structure of the first conventional device (FIG. 13).

[Related technology]
The above-mentioned prior arts are disclosed in Japanese Patent No. 5496018, “Cooling Device for Multi-Stage Electronic Devices” (Patent Document 1), Japanese Patent Application Laid-Open No. 2012-150977, “Battery Cooling Structure” (Patent Document 2), No. 221621, “Light irradiation device” (Patent Document 3).
Further, there is a technical document “Fluid Resistance of Pipes and Ducts” edited by The Japan Society of Mechanical Engineers, Jan. 1979, Maruzen, Chapter 4, page 99, FIGS. 4 and 122, and FIGS.

Japanese Patent No. 5496018 JP 2012-150977 A JP 2012-221621 A

Japan Society of Mechanical Engineers Technical Data “Fluid Resistance of Pipelines and Ducts” published by Maruzen, January 1979, Chapter 4, page 99, FIGS.

  However, in the conventional cooling device for a multi-stage electronic device, as described above, while reducing the size of the entire device, at the same time, the cooling fluid is uniformly distributed to the cooling passages of each stage of the electronic device, and the electronic devices of each stage are cooled. There is a problem that the temperature rise of the apparatus is not made equal and the cooling efficiency is not improved.

  The present invention has been made in view of the above circumstances, and when the cooling air blown from a blower is distributed in parallel to electronic devices stacked in multiple stages, while suppressing the size of a common header for branching and merging the cooling wind, In addition, a multi-stage product that evenly distributes the cooling fluid to the cooling passages of each stage of the electronic device, equalizes the temperature rise of the electronic device of each stage, and simultaneously achieves miniaturization of the entire device and improvement of cooling efficiency. An object of the present invention is to provide a cooling device for an electronic device.

  The present invention for solving the problems of the above conventional example is a cooling device of a multi-stack electronic device in which a plurality of electronic devices are stacked in a storage case, and a branch header equipped with a branch introduction flow path. A cooling header is provided with a merging introduction flow path, and the cooling fluid flows in from the lower part of the branch header, flows through the cooling flow path of the electronic device provided in parallel, and flows out from the upper part of the merging header. An inclined plate is mounted in the branch header so that the reduction rate of the flow path cross-sectional area of the branch header per parallel mounting pitch of the electronic device is increased in the upstream part of the branch header and reduced in the downstream part of the branch header. .

  The present invention is characterized in that in the cooling device for the multi-stack electronic device, the inclined plate is bent at at least two places in the middle.

  The present invention is a cooling device for a multi-stack electronic device in which a plurality of electronic devices are stacked in a storage housing, wherein a branch header equipped with a branch introduction flow path, and a merge header mounted with a merge introduction flow path. The cooling fluid flows from the lower part of the branch header, flows through the cooling passage of the electronic device provided in parallel, and flows out from the upper part of the merge header, and the branch header per parallel mounting pitch of the electronic device. Is characterized in that the side wall of the branch header has a passage wall whose reduction rate of the flow path cross-sectional area is large in the upstream part of the branch header and small in the downstream part of the branch header.

  The present invention is characterized in that in the cooling device for a multi-stage electronic device, the flow path wall is bent at least two places in the middle.

  According to the present invention, an inclination plate in which the flow path cross-sectional area reduction rate of the branch header per parallel mounting pitch of the electronic device is large in the upstream part of the branch header and small in the downstream part of the branch header is mounted in the branch header. Or, the side wall of the branch header is smoothly bent so that the flow path cross-sectional area reduction rate of the branch header per parallel mounting pitch of the electronic device is large at the upstream part of the branch header and small at the downstream part of the branch header. Since the cooling device of the multi-stage electronic device is used, the flow rate of the cooling fluid flowing into the electronic devices mounted in parallel can be controlled uniformly, so that the device can be reduced in size and the cooling efficiency can be improved at the same time.

FIG. 3 is an explanatory cross-sectional view of the first device. FIG. 4 is a diagram illustrating a relationship between a two-step bent inclined plate and a channel width in the first device. FIG. 4 is a diagram illustrating a pressure loss distribution at a branching junction in the first device. FIG. 4 is a diagram illustrating an air volume distribution of a cooling fluid in the first device. FIG. 5 is an explanatory sectional view of a second device. It is a figure which shows the relationship between the three-step bending inclined plate and flow path width in a 2nd apparatus. It is a figure which shows the pressure loss distribution in the branch junction in a 2nd apparatus. FIG. 9 is a diagram illustrating an air volume distribution of a cooling fluid in the second device. It is sectional explanatory drawing of a 3rd apparatus. FIG. 13 is a diagram illustrating a relationship between a two-step bent inclined wall and a channel width in the third device. It is sectional explanatory drawing of a 4th apparatus. FIG. 14 is a diagram illustrating a relationship between a three-step bent inclined wall and a channel width in a fourth device. It is sectional explanatory drawing of the 1st conventional apparatus. FIG. 9 is a diagram showing a pressure loss distribution at a branching junction in the first conventional device. FIG. 8 is a diagram illustrating an air volume distribution of a cooling fluid in the first conventional device. It is sectional explanatory drawing of the 2nd conventional apparatus. FIG. 11 is a diagram showing a pressure loss distribution at a branching junction in the second conventional device. FIG. 9 is a diagram showing an air volume distribution of a cooling fluid in a second conventional device. It is a figure which shows the pressure loss distribution at the branch junction in the 3rd conventional apparatus. It is a figure showing distribution of air volume of a cooling fluid in the 3rd conventional device. It is sectional explanatory drawing of the 4th conventional apparatus. It is a figure which shows the pressure loss distribution at the branch junction in the 4th conventional apparatus. FIG. 11 is a diagram illustrating an air volume distribution of a cooling fluid in a fourth conventional device.

An embodiment of the present invention will be described with reference to the drawings.
[Summary of Embodiment]
A cooling device (main cooling device) for a multi-stage electronic device according to an embodiment of the present invention includes an electronic device in which a branch header provided with a branch introduction flow channel and a merge header mounted with a merge introduction flow channel are multi-stage stacked. In the cooling channel structure in which the cooling channels of the devices are connected in parallel, the cooling fluid flows in from the lower part of the branch header, flows through the cooling channel of the electronic device, and flows out of the upper portion of the merging header. The cross-sectional area reduction rate of the flow path at the branch header is large at the upstream part of the branch header and small at the downstream part of the branch header. Without increasing the size, let the cooling air flow through the cooling passages of the multi-stage electronic device to be almost uniform, and make the temperature rise of the electronic devices in each stage uniform (uniform) so that they fall within the appropriate temperature range. It is intended to achieve the miniaturization and the cooling efficiency of the overall system at the same time.

  In addition, the cooling device connects the cooling flow paths of the multi-stacked electronic devices in parallel to the branch header having the branch introduction flow path and the merge header having the merge introduction flow path, and the cooling fluid is branched. In a cooling flow channel structure that flows in from the lower part of the header, flows through the cooling flow path of the electronic device, and flows out of the upper part of the merging header, the cross-sectional area reduction rate of the flow path in the branch header per parallel mounting pitch of the electronic device is determined by the branch header. By smoothly bending the side wall of the branch header so that it is larger at the upstream part and smaller at the downstream part of the branch header, the size of the branch header and the merge header can be increased without increasing the size of the multi-stage electronic device. An almost uniform cooling air is flowed through the cooling channel to make the temperature rise of the electronic devices in each stage uniform (uniform) so that they fall within an appropriate temperature range. It is intended to achieve the above at the same time.

[First Embodiment]
The cooling device for a multi-stage electronic device according to the first embodiment of the present cooling device is an electronic device in which a branch header provided with a branch introduction flow channel and a merge header mounted with a merge introduction flow channel are multi-stage stacked. In the cooling flow path structure, the cooling fluid flows in from the lower part of the branch header, flows through the cooling flow path of the electronic device, and flows out from the upper part of the merging header. By installing an inclined plate whose inclination angle has been changed in the middle so that the cross-sectional area reduction rate of the branch header is large at the upstream part of the branch header and small at the downstream part of the branch header, the branch is branched. Without increasing the dimensions of the header and the merged header, a substantially uniform cooling air is flowed through the cooling passages of the multi-stage electronic device, and the temperature rise of the electronic devices in each stage is made uniform and within the appropriate temperature range. To so that is what can be achieved miniaturization of the entire device and the cooling efficiency at the same time.

[First device: FIG. 1]
A first device, which is an example of a cooling device for a multi-stack electronic device according to the first embodiment, will be described with reference to FIG. FIG. 1 is an explanatory cross-sectional view of the first device.
In the first device, as shown in FIG. 1, a plurality of electronic devices 1 (PA1 to PA10) are stacked in a plurality of stages in a housing 100, and a blower 20 is provided at a cooling air inlet at a lower portion of the housing 100. An exhaust port is provided at the top of the case 100 that is connected and opposite to the blower 20.
The arrow in FIG. 1 indicates the flow of the cooling air, and flows in from point A and discharges (outflow) from point B.

As a feature of the first device, a two-step bent inclined plate 40 is provided in the branch header 4a.
The inclination angle of the two-step bent inclined plate 40 with respect to the vertical plane indicating the stacking direction of the PA is changed in the middle, and the inclination angle is large in the upstream part (lower side) and small in the downstream part (upper side). Configuration.
As a result, the rate at which the flow path cross-sectional area decreases (flow path cross-sectional area reduction rate) is large at the lower side (upstream portion) of the two-step bent inclined plate 40, and the flow path cross-sectional area decreases at the upper side (downstream portion). The rate of progress is small. That is, since the two-step bent inclined plate 40 is bent in the middle, the decrease in the flow path cross-sectional area is not constant as in a straight plate.
Details of the branch header 4a will be described later.

[Each part of the first device]
Each part of the first device will be specifically described.
[Electronic device 1]
The electronic devices 1 (PA1, PA2, PA3, PA4, PA5, PA6, PA7, PA8, PA9, PA10) are mounted in a stack of 10 stages in parallel. At this time, when the electronic devices 1 (PA1, PA2, PA3, PA4, PA5, PA6, PA7, PA8, PA9, PA10) are collectively referred to, the electronic devices 1 (hereinafter abbreviated as PA) are referred to. Parts having the same configuration will not be numbered hereafter.
Here, the electronic device 1 is an electronic device in which high-temperature electronic components such as a semiconductor device, an FET, a CPU, and a power amplifier are mounted on a circuit board at a high density.

[Cooling channel 3, branch header 4a, merge header 5, etc.]
The cooling fins 2 are mounted in the lower layer of the PA, and the cooling channels 3 are configured. In the cooling passage 3 of the PA, the cooling fluid inlet 3a is connected to the branch header 4a via the branch introduction passage 6, and the cooling fluid outlet 3b is connected to the junction header 5 via the merge introduction passage 7. I have.
Then, the cooling air is cooled from the blower 20 in another housing (not shown) via the branch header 4a to each PA, and then exhausted from the merging header 5 to the outside of the housing 100.

[Structure of branch header 4a: FIG. 2]
The branch header 4a will be described with reference to FIG. FIG. 2 is a diagram illustrating a relationship between a two-step bent inclined plate and a channel width in the first device.
As shown in FIGS. 1 and 2, by mounting the two-step bent inclined plate 40 inside the flow path of the branch header 4 a, the inside of the flow path of the branch header 4 a becomes a region 60 where the cooling fluid does not flow, It is divided into a flowing area 61.

An area 60 where the cooling fluid does not flow is an area surrounded by the branch header 4a and the two-step bent inclined plate 40, and is shaded in FIG.
In the region 61 in which the cooling fluid flows, the flow path cross-sectional area of the branch header 4a decreases in the downstream direction (upward direction in FIG. 1), but the rate at which the flow path cross-sectional area of the branch header 4a decreases depends on the branch header. The branch header 4a is formed to be large at the upstream part (lower side) and small at the downstream part (upper part) of the branch header 4a.
On the other hand, the merge header 5 is suppressed to the same size as the branch header 4a, thereby realizing the miniaturization of the entire apparatus.

  According to the configuration of the first device, by adjusting the rate at which the cross-sectional area of the flow path of the branch header 4a is reduced by the two-step bending inclined plate 40, the pressure loss generated in the merge header 5 can be reduced. The pressure loss generated in the branch header 4a downstream of the header 4a can be increased. Thus, the total pressure loss can be made substantially equal regardless of the flow path of the cooling passage of the multi-stage electronic device, and the branch header 4a and the merge header 5 can be increased without increasing the width in the lateral direction. A uniform flow rate can be passed through the cooling flow path.

In order to explain this operation in detail, the same stacking mounting conditions as in FIG. 13, PA is stacked and mounted at a pitch of 100 mm, the branch header 4a and the junction header 5 both have a maximum thickness of 100 mm, a depth of 650 mm, and a branch introduction. The flow path 6 and the merging introduction path 7 simulate the flow under the general condition that the height is 36 mm, the length is 40 mm, and the total air flow is 30 m ³ / min, and the cooling passing through each PA is performed. The air volume and the pressure loss caused by the branching and joining of the cooling channels were determined.

As shown in FIG. 2, the condition of the two-step bent inclined plate 40 is as follows: from PA10 (lowest step PA) to PA7, the branch header 4a which is the gap between the two-step bent inclined plate 40 and the branch introduction flow path 6; Has a slant angle that decreases by 17 mm for each PA mounting pitch.
Also, from PA6 to PA1 (the uppermost PA), the inclination of the passage width of the branch header 4a, which is the gap between the two-step bent inclined plate 40 and the branch introduction passage 6, becomes smaller by 4.25 mm for each PA mounting pitch. Have an angle.

[Pressure loss distribution at branching junction: FIG. 3, cooling air flow distribution: FIG. 4]
The result of the simulation in the first device will be described with reference to FIGS. FIG. 3 is a diagram illustrating a pressure loss distribution at a branching junction in the first device, and FIG. 4 is a diagram illustrating a flow rate distribution of a cooling fluid in the first device.
In FIG. 3, the pressure loss ΔPhi in the branch header 4a from the total inlet (point A) of the branch header 4a to the cooling fluid inlet 3a of each PA, the pressure loss ΔPbi in the branch introduction flow path 6, and the pressure loss in the merge introduction path 7 ΔPbo, pressure loss ΔPho in the junction header 5 from the cooling fluid outlet 3b of each PA to the total exit (point B) of the junction header 5 and the like are shown for each PA stage as a pressure loss distribution generated at the branching junction of the cooling flow path. It is a thing.

  FIG. 4 shows the distribution of the flow rate of the cooling fluid passing through the cooling flow path in the PA. The sum of the pressure losses ((ΔPhi + ΔPbi + ΔPbo + ΔPho)) is shown. It was found that the deviation from the average pressure loss value was + 4% to -3% between all PAs, and the deviation from the average air volume could be significantly reduced to ± 2% between all PAs.

[Effect of First Embodiment]
As described above, according to the cooling device for a multi-stage electronic device according to the first embodiment, the dimensions of the branch header and the merge header are not increased, and the cooling air flow in the cooling passage of the multi-stage electronic device is substantially uniform. Flows, the temperature rise of the electronic devices in each stage is uniform (uniform) and falls within an appropriate temperature range, so that there is an effect that the entire device can be reduced in size and the cooling efficiency can be improved at the same time.

[Second embodiment]
The cooling device of the multi-stage electronic device according to the second embodiment of the present cooling device has a structure in which the inclination angle is changed to two points, the structure of the inclined plate is bent in three steps, and the pressure loss can be finely adjusted. It was done.
The change point of the inclination angle of the inclined plate may be three or more, and may be a smooth curved surface.

[Second device: FIGS. 5 and 6]
A second device which is an example of a cooling device for a multi-stack electronic device according to a second embodiment will be described with reference to FIGS. FIG. 5 is an explanatory cross-sectional view of the second device, and FIG. 6 is a diagram showing a relationship between the three-step bent inclined plate and the flow channel width in the second device. The same components as those of the first device are denoted by the same reference numerals, and description thereof will be omitted.
In the second device, as shown in FIG. 5, a three-step bent inclined plate 41 is mounted inside the flow path of the branch header 4b as shown in FIG.
The inside of the branch header 4b is divided into a region 62 where the cooling fluid does not flow and a region 63 where the cooling fluid flows.

An area 62 through which the cooling fluid does not flow is an area surrounded by the branch header 4b and the three-step bent inclined plate 41, and is shaded in FIG.
In the region 63 where the cooling fluid flows, the flow path cross-sectional area of the branch header 4b decreases toward the downstream side (upward in FIG. 5), but the rate of decrease in the flow path cross-sectional area of the branch header 4b depends on the branch header 4b. The flow path cross-sectional area of the upstream and downstream branch headers 4b is large in the upstream part (lower part), small in the downstream part (upper part) of the branch header 4b, and in the middle part (intermediate part) of the branch header 4b. Take the median of the decreasing rate.
On the other hand, the merge header 5 is suppressed to the same size as the branch header 4b, thereby realizing the miniaturization of the entire apparatus.

  With the configuration of the second device, the rate at which the cross-sectional area of the flow path of the branch header 4b is reduced by the three-step bent inclined plate 41 can be finely adjusted. That is, it is possible to finely adjust and increase the pressure loss generated in the branch header 4b with respect to the pressure loss generated in the merged header 5, so that the total pressure loss does not pass through the cooling passage of any multi-stage electronic device. Can be made equal, and a uniform flow rate can be passed through the cooling flow path of the multi-stack electronic device without increasing the lateral thickness of the branch header 4b and the merge header 5.

In order to explain this operation in detail, the same stacking mounting conditions as in FIG. 13, PA are stacked and mounted at a pitch of 100 mm, the branch header 4b and the merge header 5 both have a maximum lateral thickness of 100 mm, a depth of 650 mm, and a branch. The flow path is simulated under the general conditions of a height of 36 mm, a length of 40 mm, and a total air flow of 30 m ³ / min. The cooling air volume and the pressure loss caused by the branching and joining of the cooling channels were determined.

As shown in FIG. 6, the condition of the three-step bent inclined plate 41 is as follows: from PA10 (lowest stage PA) to PA7, the branch header 4b, which is the gap between the three-step bent inclined plate 41 and the branch introduction flow path 6; Has an inclination angle of 19.5 mm smaller for each PA mounting pitch.
Also, from PA6 to PA5, the width of the flow path of the branch header 4b, which is the gap between the three-step bent inclined plate 41 and the branch introduction flow path 6, has an inclination angle of 6.7 mm smaller for each PA mounting pitch. .
From PA4 to PA1 (uppermost PA), the inclination angle at which the flow path width of the branch header 4b, which is the gap between the three-step bent inclined plate 41 and the branch introduction flow path 6, becomes smaller by 4.4 mm for each PA mounting pitch. have.

[Distribution of pressure loss at branch junction: FIG. 7, distribution of air flow of cooling fluid: FIG. 8]
The result of the simulation in the second device will be described with reference to FIGS. FIG. 7 is a diagram showing a pressure loss distribution at the branching junction in the second device, and FIG. 8 is a diagram showing an air volume distribution of the cooling fluid in the second device.
In FIG. 7, the pressure loss ΔPhi in the branch header 4b from the total inlet (point A) of the branch header 4b to the cooling fluid inlet 3a of each PA, the pressure loss ΔPbi in the branch introduction flow path 6, and the pressure loss in the merge introduction path 7 ΔPbo, pressure loss ΔPho in the junction header 5 from the cooling fluid outlet 3b of each PA to the total exit (point B) of the junction header 5 and the like are shown for each PA stage as a pressure loss distribution generated at the branching junction of the cooling flow path. It is a thing.

  FIG. 8 shows the distribution of the flow rate of the cooling fluid passing through the cooling flow path in the PA. The sum of the pressure losses (ΔPhi + ΔPbi + ΔPbo + ΔPho) is such that the deviation from the average pressure loss value between all PAs is + 3% to −2%, It was found that the deviation from the average airflow between all PAs could be significantly reduced to ± 0.5%.

Therefore, by further increasing the number of times of bending of the bent inclined plate 41 attached to the branch header 4b, the amount of cooling air flowing through the cooling passages of all PAs can be averaged with high accuracy.
Alternatively, it is needless to say that even if an inclined plate having a smooth curvature is attached instead of bending, the present invention can be carried out with appropriate changes without departing from the spirit of the present invention.

[Third Embodiment]
A cooling device for a multi-stage electronic device according to a third embodiment of the present cooling device is an electronic device in which a branch header provided with a branch introduction flow channel and a merge header mounted with a merge introduction flow channel are multi-tiered. In the cooling channel structure, the cooling fluid flows in parallel from the lower part of the branch header, flows through the cooling channel of the electronic device, and flows out from the upper part of the merging header. Of the branch header is large at the upstream part of the branch header, small at the downstream part of the branch header, and by bending the side wall of the branch header so that the inclination angle is different, the branch header and the junction header are merged. Without increasing the size of the electronic device, a substantially uniform cooling air flows in the cooling passages of the multi-stage electronic device, and the temperature rise of the electronic device in each stage is uniform and within an appropriate temperature range, It is capable of achieving downsizing of 置全 body and cooling efficiency at the same time.

[Third device: FIGS. 9 and 10]
A third device, which is an example of a cooling device for a multi-stack electronic device according to the third embodiment, will be described with reference to FIGS. FIG. 9 is an explanatory cross-sectional view of the third device, and FIG. 10 is a diagram illustrating a relationship between a two-step bent inclined wall and a flow channel width in the third device. The same components as those of the first device are denoted by the same reference numerals, and description thereof will be omitted.
In the third device, as shown in FIG. 9, the branch header 8 has a two-step bent inclined wall 50 in which the side wall of the branch header 8 is bent in two steps as shown in FIG.

Although the two-step bent inclined wall 50 is provided with the two-step bent inclined plate 40 in the branch header 4a in the first device, the two-step bent inclined plate 40 is used as a wall (flow path wall) of the branch header 8. It has become something.
Therefore, the shape of the inner wall of the two-step bent inclined wall 50 is the same as the inner shape of the two-step bent inclined plate 40.

In the inside of the flow path of the branch header 8, the flow path cross-sectional area of the branch header 8 decreases toward the downstream side (upward in FIG. 9). It is formed so as to be large at the portion (lower side) and smaller at the downstream portion (upper side) of the branch header 8.
On the other hand, the merging header 5 is suppressed to the same size as the branch header 8, thereby realizing the downsizing of the entire apparatus.

  According to the configuration of the third device, the rate at which the cross-sectional area of the flow path of the branch header 8 is reduced can be adjusted by the two-step bent side wall 50. , The pressure loss occurring in the branch header 8 on the downstream side can be increased. Thus, the total pressure loss can be made substantially equal regardless of the flow path of the cooling flow path of the multi-stage electronic device, and without increasing the lateral thickness of the branch header 8 and the merge header 5. A uniform flow rate can be made to flow through the cooling passage.

In order to explain this operation in detail, the same stacking mounting conditions as in FIG. 1, PA are stacked and mounted at a pitch of 100 mm, the branch header 8 and the merge header 5 both have a maximum lateral thickness of 100 mm, a depth of 650 mm, and a branch. The flow path is simulated under the general conditions of a height of 36 mm, a length of 40 mm, and a total air flow of 30 m ³ / min. The cooling air volume and the pressure loss caused by the branching and joining of the cooling channels were determined.

As shown in FIG. 10, the condition of the two-step bent inclined wall 50 of the branch header 8 is as follows: from PA10 (lowest step PA) to PA7, the two-step bent inclined wall 50 of the branch header 8 The flow path width of the branch header 8, which is the gap of the above, has an inclination angle of decreasing by 17 mm for each PA mounting pitch.
From PA6 to PA1 (the uppermost PA), the flow width of the branch header 8, which is the gap between the two-step bent inclined wall 50 of the branch header 8 and the branch introduction flow path 6, is set to 4. It has an inclination angle that is reduced by 25 mm.

[Result of Simulation of Third Device]
As a result of the simulation of the third apparatus, the pressure loss sum ((ΔPhi + ΔPbi + ΔPbo + ΔPho) from the total entrance (point A) of the branch header 8 to the total exit (point B) of the junction header 5 is approximately equal to the pressure loss passing through each PA. As in the case of the first device, the deviation from the average pressure loss value between all PAs was + 4% to -3%, and the deviation from the average airflow between all PAs was ± 2%. It turns out that it can be made much smaller.

[Effects of Third Embodiment]
As described above, according to the cooling device for a multi-stage electronic device according to the third embodiment, the size of the branch header and the merge header is not increased, and the cooling air flow path of the multi-stage electronic device is substantially uniform. Flows, the temperature rise of the electronic devices in each stage is uniform (uniform) and falls within an appropriate temperature range, and there is an effect that the device can be reduced in size and the cooling efficiency can be improved at the same time.

[Fourth Embodiment]
The cooling device of the multistage stacked electronic device according to the fourth embodiment of the present cooling device has two points where the inclination angle is changed, the structure of the inclined wall (flow path wall) is bent in three steps, and the pressure loss is reduced. It can be adjusted slightly.
The change point of the inclination angle of the inclined wall may be three or more, and may be a smooth curved surface.

[Fourth device: FIGS. 11 and 12]
A fourth device which is an example of a cooling device for a multi-stack electronic device according to a fourth embodiment will be described with reference to FIGS. FIG. 11 is an explanatory cross-sectional view of the fourth device, and FIG. 12 is a diagram showing the relationship between the three-step bent inclined wall and the flow channel width in the fourth device. The same components as those of the first device are denoted by the same reference numerals, and description thereof will be omitted.
In the fourth device, as shown in FIG. 11, the branch header 9 has a three-step bent inclined wall 51 in which the side wall 51 of the branch header 9 is bent in three steps as shown in FIG.
Although the three-step bent inclined wall 51 is provided with the three-step bent inclined plate 41 in the branch header 4b in the second device, the three-step bent inclined plate 41 is used as the wall of the branch header 9. .

In the inside of the flow path of the branch header 9, the flow path cross-sectional area of the branch header 9 decreases toward the downstream side (upward in FIG. 11). In the middle portion (intermediate portion) of the branch header 9, the flow path cross-sectional area of the upstream and downstream branch headers 9 decreases. Take the median of the percentages.
On the other hand, the merge header 5 is suppressed to the same size as the branch header 9 to realize a compact apparatus as a whole.

  According to the configuration of the fourth device, the rate at which the cross-sectional area of the flow path of the branch header 9 is reduced by the three-step bent side wall 51 can be finely adjusted. That is, since the pressure loss generated in the branch header 9 can be finely adjusted and increased with respect to the pressure loss generated in the merged header 5, the total pressure loss can be reduced regardless of the cooling flow path of any multi-stage electronic device. It is possible to make the flow rate uniform, and to make the flow rate uniform in the cooling flow channel of the multi-stage electronic device without increasing the lateral thickness of the branch header 9 and the merge header 5.

In order to explain this operation in detail, the same stacking mounting conditions as in FIG. 1, PA are stacked and mounted at a pitch of 100 mm, the branch header 9 and the merge header 5 both have a maximum thickness of 100 mm, a depth of 650 mm, and a branch introduction. The flow path 6 and the merging introduction path 7 simulate the flow under the general condition that the height is 36 mm, the length is 40 mm, and the total air flow is 30 m ³ / min, and the cooling passing through each PA is performed. The air volume and the pressure loss caused by the branching and joining of the cooling channels were determined.

As shown in FIG. 12, the condition of the three-step bent inclined wall 51 is as follows: from PA10 (lowest step PA) to PA7, the branch header 9 which is the gap between the three-step bent inclined wall 51 and the branch introduction flow path 6 is used. The flow path width has an inclination angle that becomes smaller by 19.5 mm for each PA mounting pitch.
Further, from PA6 to PA5, the flow passage width of the branch header 9, which is the gap between the three-step bent inclined wall 51 and the branch introduction flow passage 6, has an inclination angle at which the width becomes smaller by 6.7 mm for each PA mounting pitch. .
Further, from PA4 to PA1 (the uppermost PA), the inclination width at which the flow path width of the branch header 9, which is the gap between the three-step bent inclined wall 51 and the branch introduction flow path 6, becomes smaller by 4.4 mm for each PA mounting pitch. Have an angle.

[Result of Simulation of Fourth Device]
As a result of the simulation of the fourth device, the pressure loss sum ((ΔPhi + ΔPbi + ΔPbo + ΔPho) from the total entrance (point A) of the branch header 9 to the total exit (point B) of the junction header 5 is almost equal to the pressure loss passing through each PA. The difference in the average pressure loss value between all PAs was + 3% to −2%, and the air flow was ± 0.5% in deviation from the average air flow among all PAs, similarly to the second apparatus. % Can be significantly reduced.

[Effects of Fourth Embodiment]
As described above, according to the cooling device for a multi-stage electronic device according to the fourth embodiment, the dimensions of the branch header and the merge header are not increased, and the cooling air flow in the cooling passage of the multi-stage electronic device is substantially uniform. Flows, the temperature rises of the electronic devices at each stage are uniform (uniform) and within an appropriate temperature range, so that there is an effect that the size of the device can be reduced and the cooling efficiency can be improved at the same time.

Therefore, in the fourth device, by further increasing the number of times of bending the bent inclined wall 51 of the branch header 9, the amount of cooling air flowing through the cooling passages of all PAs can be averaged with high accuracy.
Alternatively, instead of bending, an inclined wall having a smooth curvature may be formed.

  Further, although the cooling device according to the embodiment of the present invention has been described with ten stages, the number of stages may be other than ten, and the cooling fluid is described as air, which is a gas. However, it is needless to say that the cooling fluid may be a liquid, and the cooling fluid may be appropriately changed without departing from the spirit of the present invention.

  The present invention is intended to reduce the size of a common header for branching and merging cooling air when distributing cooling air sent from a blower in parallel to electronic devices stacked in multiple stages, and to reduce the cooling flow of each stage of the electronic device. The present invention is suitable for a cooling device of a multi-stage electronic device in which a cooling fluid is evenly distributed in a passage and the temperature of the electronic device in each stage is made equal, thereby achieving a reduction in size of the entire device and an improvement in cooling efficiency at the same time.

  DESCRIPTION OF SYMBOLS 1 ... Electronic device (PA), 2 ... Cooling fin, 3 ... Cooling channel, 3a ... Cooling fluid inflow port, 3b ... Cooling fluid outflow port, 4, 4a, 4b, 8, 9 ... Branch header, 5 ... Merging header Reference numeral 6: Branch introduction passage, 7: Merging introduction passage, 20: Blower, 40: Two-stage bent inclined plate, 41: Three-stage bent inclined plate, 50: Two-stage bent inclined wall, 51: Three-stage bent inclined wall Reference numerals 60, 62: regions where cooling fluid does not flow, 61, 63: regions where cooling fluid flows, 100: housing

Claims (4)

A cooling device for a multi-stage electronic device in which a plurality of electronic devices are stacked in a storage case,
A branch header equipped with a branch introduction flow path,
A merging header equipped with a merging introduction flow path,
A cooling fluid flows in from a lower part of the branch header, flows through a cooling passage of the electronic device provided in parallel, and flows out from an upper part of the merge header.
An inclined plate is mounted in the branch header so that the reduction rate of the flow path cross-sectional area of the branch header per parallel mounting pitch of the electronic device is large in the upstream part of the branch header and small in the downstream part of the branch header. A cooling device for a multi-stage electronic device, comprising:   2. The cooling device for a multi-stack electronic device according to claim 1, wherein the inclined plate is bent at least at two places in the middle. A cooling device for a multi-stage electronic device in which a plurality of electronic devices are stacked in a storage case,
A branch header equipped with a branch introduction flow path,
A merging header equipped with a merging introduction flow path,
A cooling fluid flows in from a lower part of the branch header, flows through a cooling passage of the electronic device provided in parallel, and flows out from an upper part of the merge header.
The side wall of the branch header is a flow path wall in which the reduction rate of the flow path cross-sectional area of the branch header per parallel mounting pitch of the electronic device is large in the upstream part of the branch header and small in the downstream part of the branch header. A cooling device for a multi-stage electronic device, comprising:   4. The cooling device for a multi-stage electronic device according to claim 3, wherein the flow path wall is bent at at least two places in the middle.