JPH09214161A - Electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat transfer in fluid refrigerant, and making an electronic device suitable for highly heating characteristics caused by high density of electronic modules, by inserting a thin plate inside a cooling plate molded in an extrusion machine, separating inner ventilation paths, and making a short side of a ventilation path small. SOLUTION: An electronic device includes an electronic module 1, a cooling plate 2, and a thin plate 5. The thin plate 5 is inserted in the cooling plate 2 molded in an extrusion machine to separate the ventilation paths. Then, a short side of the path is made small and a thermal boundary layer is made thin, so a coefficient of heat transfer is made large. The heat condition is changed to one-side adiabatic condition, because there is no heat flux between the thin plate 5 and the refrigerant, but in this case an effect of improvement exceeds the demerit of the one-side adiabatic condition. When the thickness of the plate is increased, the flowing path is made thinner and the coefficient of heat transfer can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device that indirectly cools a plurality of electronic modules equipped with heating elements that require cooling.

[0002]

2. Description of the Related Art FIG. 4A is a plan view showing a configuration of a conventional electronic device, and FIG. 4B is a view showing a cross section EE in the conventional electronic device shown in FIG. 4A. Further, FIG.
4B are views showing the cross section FF in FIG. 4B, FIG. 5A shows a non-operating state, and FIG. 5B shows an operating state. In the figure, 1 is an electronic module, 2 is a cooling plate for indirectly cooling the electronic module with a liquid, 3 is a manifold for distributing and collecting a liquid refrigerant to and from the cooling plate, and 4 is a manifold and the cooling plate. It is a joint to connect.

Conventional electronic equipment is constructed as described above,
During operation, the liquid refrigerant is distributed by the manifold 3 and supplied to the cooling plate 2 via the joints 4 in each row, and the cooling plate 2 swells as shown in FIG. 5B due to the pressure of the supplied refrigerant. 1, the electronic module 1 is cooled and then collected in the manifold 3 via the joint 4. Further, when not in operation, as shown in FIG. 5A, there is a clearance between the cooling plate 2 and the electronic module 1, and the electronic module 1 can be easily exchanged if necessary.

[0004]

In the conventional electronic equipment as described above, since the cooling plate repeatedly deforms due to repeated operation / non-operation during operation, the reliability of the cooling plate against repeated deformation is ensured. It is necessary to rely on extrusion without a joint as a flow path shape molding method. However, in extrusion molding, there was a limit to the thinning of the flow path and the cooling area that can be secured due to manufacturing problems.

On the other hand, the flow of the liquid refrigerant in the cooling plate becomes a laminar flow region because it is difficult to secure a large flow rate due to the restriction of the refrigerant circulation capacity. Also, in extrusion molding, it is impossible to change the cross section of the liquid refrigerant along the flow, and it is impossible to make the flow turbulent and improve the heat transfer performance.

It is well known that in convective heat transfer by laminar flow, in order to secure cooling performance (heat transfer coefficient) in a developed flow region, it is necessary to make the flow path as thin as possible and the temperature boundary layer thin. On the street. Here, if the basic equation "Numerical formula 1" for calculating the convection heat transfer coefficient is cited, the heat transfer coefficient α is proportional to the Nusselt number Nu and the heat conductivity λ, and the flow path equivalent diameter d that is the flow path representative dimension is It turns out that they are inversely proportional.

[0007]

[Equation 1]

Here, if the parameters such as the physical property value and the flow rate of the liquid refrigerant are fixed as known, the heat transfer coefficient depends on the equivalent diameter of the flow path, and the smaller this value is, the better the heat transfer coefficient is obtained. It will be. In a thin and flat flow path shape as shown in FIG. 5 (a), the flow path equivalent diameter d is obtained by "Equation 2" using the flow path short side dimension a and the long side dimension b, and a << b In the case of, it is almost proportional to the a dimension regardless of the b dimension.

[0009]

[Equation 2]

However, as described above, in extrusion molding, it is reciprocally difficult to make the size a small and the size b large due to manufacturing restrictions.

In some electronic devices, the heat generating part of the electronic module may be locally distributed. In this case, since the heat generating part is entirely covered, it is necessary to secure a large cooling area of the cooling plate. , The liquid refrigerant that can contribute to the local cooling of the heat generating part is limited to the area directly below the heat generating part of the electronics module, and after cooling multiple electronic modules, it is also distributed to the temperature rise of the liquid refrigerant due to the heat distribution of the electronics modules. In some cases, the entire flow rate of the liquid refrigerant cannot be effectively utilized for cooling due to the occurrence of the above phenomenon.

The present invention has been made to solve the above problems, and improves the heat transfer performance of a liquid refrigerant while maintaining the functional reliability of a cooling plate by extrusion molding, and improves the performance of an electronic module. It is intended to provide an electronic device that can cope with high heat generation due to high density.

[0013]

In the electronic apparatus according to the present invention, a thin plate is inserted into an extruded cooling plate, and the flow path inside the cooling plate is divided to further reduce the short side dimension of the flow path. It has been transformed.

Further, in the electronic device according to the present invention, a flow path is formed inside the extruded cooling plate in accordance with the heat generation distribution of the electronic module so that a minimum cooling performance can be secured immediately below the high heat generating portion, A thick step plate that is thickly formed so as to impede the flow of the refrigerant is inserted in the heat generating portion, and it is possible to efficiently contribute the entire liquid refrigerant flowing to the cooling plate to cooling.

Further, in the electronic device according to the present invention, the internal flow path of the extruded cooling plate is divided, and the liquid refrigerant flows alternately from one flow path to the other flow path. By inserting the path bypass plate, peeling the temperature boundary layer once developed in one flow path, and then reattaching it in the other flow path, by repeating the phenomenon,
It is possible to obtain a high heat transfer coefficient at the reattachment point. At this time, the reattachment point of the boundary layer is set in the vicinity immediately below the heat generating portion of the electronics module.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1. FIG. 1 is a sectional view showing Embodiment 1 of the present invention. In the figure, 1 is an electronics module, 2 is a cooling plate, and 5 is a thin plate.

In FIG. 1, by inserting a thin plate 5 inside the extrusion-molded cooling plate 2, the flow path is divided to further reduce the short side of the flow path, thereby making the temperature boundary layer thin and the heat transfer coefficient. Can be increased. In this case, since no heat flux is generated between the thin plate 5 and the refrigerant, the one-sided heat insulation condition is established. In the laminar heat transfer of a thin flat flow channel, it is reported as an analytical value that the ratio of Nusselt number in the case of single-sided heat insulation to the case in which heat flux occurs on both sides is larger than 0.5. Therefore, an improvement effect exceeding the disadvantage of changing to the single-sided heat insulation condition by simply dividing the flow path into two can be obtained, and by increasing the plate thickness, the flow path can be made thinner and the heat transfer coefficient can be increased. It is possible to improve. As a result, the short side of the flow path can be made smaller, and the heat transfer coefficient can be improved by making the boundary layer thinner.

Embodiment 2. 2 is a sectional view showing a second embodiment of the present invention. In the figure, 1 is an electronic module, 2 is a cooling plate, 6 is a heat generating part inside the electronic module, and 7 is a heat generating part 6 inside the electronic module. As shown in FIG. It is a wall-thickness step plate in which the wall thickness is distributed so as to form a flow path.

In FIG. 2, by supplying a wall thickness step plate 7 having a wall thickness changed so as to form a flow path only directly under the heat generating portion 6 of the electronic module, inside the extrusion cooling plate 2, supply is performed. By flowing all of the generated liquid refrigerant in the vicinity of directly below the heat generating portion 6 of the electronics module to contribute to cooling, it is possible to equalize the liquid temperature rise in the cooling plate and perform efficient cooling.

Embodiment 3 3 is a sectional view in the liquid refrigerant flow direction showing Embodiment 3 of the present invention. In the figure, 1 is an electronic module, 2 is a cooling plate, 6 is a heat generating portion inside the electronic module, 8 is an internal flow passage of the cooling plate, and the liquid refrigerant flows alternately from one flow passage to the other flow passage. It is a flow path bypass plate having wings that are alternately bent.

In FIG. 3, the extruded cooling plate 2 is shown.
By dividing the internal flow path of, and inserting the flow path bypass plate 8 having the blades that are alternately bent so that the liquid refrigerant alternately flows from one flow path to the other flow path,
Higher cooling due to the effect of improving the heat transfer coefficient at the boundary layer reattachment point by repeating the phenomenon of separating the temperature boundary layer once developing in one flow channel and then infiltrating it into the other flow channel and reattaching it The performance can be obtained. At this time, as shown in the figure, if the redeposition point of the boundary layer is set near the heat generating portion 6 inside the electronic module, more efficient cooling performance can be obtained.

In the above description, the present invention has been described with reference to an electronic device in which an electronic module requiring cooling is arranged, but it goes without saying that the present invention can be applied to a device having a similar thin duct cooling tube.

[0023]

Since the present invention is configured as described above, it has the following effects.

According to the present invention, by inserting a thin plate inside the extruded cooling plate, the flow path is divided to further reduce the short side of the flow path, thereby making the temperature boundary layer thin and the heat transfer coefficient. Can be increased. Further, in this case, the improvement effect exceeding the demerit of changing to the single-sided heat insulation condition can be obtained only by dividing the flow path into two, and by increasing the plate thickness, the flow path can be made thinner and the heat transfer coefficient can be increased. Can be greatly improved.

According to the present invention, by inserting the thick step plate whose wall thickness is changed according to the heat generation distribution of the electronic module into the extruded cooling plate, all the supplied liquid refrigerant is supplied to the electronic module. By making the liquid flow in the vicinity of directly under the heat generating portion to contribute to cooling, the liquid temperature rise in the cooling plate can be equalized and efficient cooling can be performed.

According to the present invention, the flow path bypass plate has a shape in which the internal flow path of the extruded cooling plate is divided and the liquid refrigerant flows alternately from one flow path to the other flow path. By inserting, the phenomenon of delamination of the temperature boundary layer once developed in one channel, then invasion into the other channel and reattachment is repeated, and heat transfer at the boundary layer reattachment point. High cooling performance can be obtained due to the effect of improving the rate.

[Brief description of drawings]

FIG. 1 is a sectional view showing Embodiment 1 of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3 is a sectional view in a liquid refrigerant flow direction showing a third embodiment of the present invention.

FIG. 4 is a configuration diagram showing a conventional electronic device.

5 is a diagram showing an operating state and a non-operating state of a cross section FF shown in FIG.

[Explanation of symbols]

1 electronics module, 2 cooling plate, 3 manifold, 4 joints, 5 thin plate, 6 heat generating part, 7 thick step plate, 8 flow path bypass plate.

Claims (3)

[Claims] 1. A plurality of electronic modules that are provided with heating elements that require cooling and are arranged at a predetermined interval, and are arranged in a gap between each row of electronic modules for indirectly liquid cooling the electronic modules. Electronic device including a cooling plate having thin parallel plate flow paths formed by extrusion molding, a manifold for distributing a liquid refrigerant to each of the row cooling plates, and a joint for connecting the cooling plate and the manifold In the electronic device, the thin plate for dividing the flow path is provided in the flow path of the cooling plate. 2. A plurality of electronic modules that are provided with heating elements that require cooling and are arranged at a predetermined interval, and are arranged in a gap between each row of electronic modules for indirectly liquid cooling the electronic modules. Electronic device including a cooling plate having thin parallel plate flow paths formed by extrusion molding, a manifold for distributing a liquid refrigerant to each of the row cooling plates, and a joint for connecting the cooling plate and the manifold In the electronic device, the cooling plate channel has a wall thickness step plate whose plate thickness is changed in a plane perpendicular to the flow of the refrigerant according to the heat generation distribution of the electronic module. 3. A plurality of electronic modules that are provided with heating elements that require cooling and are arranged at predetermined intervals, and are arranged in the gaps between each row of electronic modules for indirectly liquid cooling the electronic modules. Electronic device including a cooling plate having thin parallel plate flow paths formed by extrusion molding, a manifold for distributing a liquid refrigerant to each of the row cooling plates, and a joint for connecting the cooling plate and the manifold In the electronic device, the flow path of the cooling plate is divided, and the flow path bypass plate has a shape such that the liquid refrigerant alternately flows from one flow path to the other flow path.