JPS5917560B2 - Cooling methods for electronic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling method for an electronic device that has a mechanism for cooling the electronic device with a jet stream and adiabatically expanding air or gas in the middle of a piping system.

■0 Conventional cooling methods for electronic devices include, for example,
Something like the one shown in the figure is known.

In the figure, 1-1 to 1-3 indicate printed boards on which electronic components are mounted, and 2-1 and 2-2 indicate cooling fans. Although the printed board is not shown, it is mounted on a rack. j5
The air flow passes between the printed boards as indicated by the arrows. In this type of parallel air flow cooling method, the wind speed is limited to about 10 m/sec to 20 m/sec, and since a large fan is used, noise problems occur. In addition, the heat transfer RO rate of parallel airflow is on the order of tens to hundreds of -/m''・Hr・℃, and has the disadvantage that the cooling capacity is smaller than that of liquid cooling.Furthermore, As can be seen from Figure 4, the upper printed board group 1-1.1-
2 is cooled by the air flow warmed by the printed board group 1-3 below, but it is not cooled sufficiently. In order to increase the cooling capacity, it is sufficient to lower the temperature of the cooling air, but conventionally, for this purpose, the refrigerator or
The following refrigerant is used.

Such a method has the disadvantage of high equipment costs. A liquid cooling system in which a cooling plate is attached to a printed circuit board and the cooling plate is cooled with a cooling medium is excellent in terms of cooling capacity, but has problems in terms of cost and maintenance.

The present invention is based on the above consideration, and an object of the present invention is to provide a cooling method for electronic devices that has excellent cooling capacity and is easy to maintain.

Therefore, the electronic device cooling method of the present invention includes an electronic device configured by mounting a plurality of electronic components on a substrate and having a surface parallel to the surface of the substrate, and a plurality of dinit flow jetting nozzles. The above-mentioned dinit header comprises a dinit header composed of an isobaric container, a piping system for supplying compressed air or compressed gas to the dinit header, and a mechanism for generating adiabatic expansion provided in the piping system. is arranged so as to overlap the substrate of the electronic device, and the free dinit flow section of the dinit stream jetted from each of the plurality of dinit flow jetting nozzles of the dinit header has a vertical component with respect to the surface of the substrate. The present invention is characterized in that the liquid is sprayed onto a locally increased temperature portion of the electronic device. The present invention will now be described with reference to the drawings. Figures 2, 3, and 4 are block diagrams of the first, second, and third embodiments of the present invention, and Figure 5 shows the board and dinit header on which electronic components are mounted. It is.

In the figure, 1 is a board such as a printed circuit board, 3 is an electronic component such as an IC chip, 4 is a dinit header, 5 is an isobaric container, 6 is a dinit flow jet nozzle, 7 is an air introduction pipe, 8
is an adiabatic expansion valve, nozzle or capillaries.
ry), 9 is an air pipe, 10 is an air chamber or distributor, 11 is an air compressor,
12 represents a pressure gauge, and 13 represents a heat exchanger.
First, a first embodiment of the present invention will be described with reference to FIG.

The intake air is pressurized by an air compressor 11 and sent to an air chamber or distributor 10. A number of air lines 9 are connected to the air chamber or distributor 10, and a dinit header 4 is connected to each air line 9. The air supply port of Ginnit header 4 has an adiabatic expansion valve,
An adiabatic expansion mechanism 8 such as a nozzle or a capillary is provided, and when air passes through the adiabatic expansion mechanism 8, its temperature decreases. For example, when pressurized air with a pressure of 1.5/CTIl temperature of 20°C is ejected into the atmosphere through a nozzle, the ejection temperature is -9.5°C, which is about 30°C at the center of the jet compared to the pressurized air temperature.
°C low temperature air flow is obtained. However, in the case of impinging jet cooling, the flow velocity is O at the turning point in the center of the jet,
Since the above temperature returns to the pressurized air temperature at the nozzle inlet,
The effect of low-temperature flow is exhibited within the range of flow velocity.

As is well known, the temperature change due to adiabatic expansion depends on the pressure difference or the air volume ratio. Therefore, the cooling temperature of the air is controlled by the pressure and the throttle of the adiabatic expansion mechanism 8. The air introduced into the dinit header 4 via the adiabatic expansion mechanism 8 is ejected from the jet nozzle 6 as a dinit stream. As is clear from FIG. 5, the dinit header 4 is composed of an isobaric vessel 5 in which a number of jet nozzles 6 are provided. The electronic component 3 is, for example, an IC chip or an IC package, and the size of the chip, which is a heating element, is 1 mm square to several mm square.

The air introduced from the air introduction pipe 7 is ejected from the nozzle 6 as a dinit flow. The cross-sectional shape of the nozzle 6 can be circular, slit, or irregularly shaped, such as a cross. The dinit stream is blown directly onto the electronic component 3, which is the area where the local temperature rises. One nozzle 6 is used for one part.
Alternatively, a plurality of nozzles 6 may be provided to correspond to one electronic component in consideration of clogging of the nozzles 6. Further, if the IC chip, that is, the electronic component 3 is small, one nozzle 6 may correspond to a plurality of electronic components. The dinit flow consists of a free dinit flow section, a colliding dinit flow section, and a wall dinit flow section, but does the dinit flow collide with the free dinit flow section? The impingement dinit flow section refers to the dinit flow section at the collided section, and the wall dinit flow section refers to the dinit flow section that flows along the wall after the collision. The most heat is removed from the electronic component 3 in the collision "dinite flow section. By vertically blowing the dinit flow, the air boundary layer on the surface of the cooling object becomes thinner, so the heat transfer coefficient of the dinit flow is several hundred. or a thousand or more Kcat/m”・
The heat transfer coefficient is approximately Hr·°C, which is one order of magnitude higher than the heat transfer coefficient of parallel air flow. When the dinit flow was blown perpendicularly to the substrate 1, the maximum cooling efficiency was obtained when the distance between the substrate 1 and the nozzle 6 was H and the nozzle diameter was D.

Of course, the dinit stream may be blown obliquely onto the substrate 1 in order to perform the exhaust smoothly. In the case shown in FIG. 2, the dinit stream is directly blown onto the electronic components 3, but if the substrate 1 is made of a material with good thermal conductivity, such as alumina porcelain or beryllia porcelain, the dinit stream is blown directly onto the electronic components 3. Instead of spraying, it is also possible to spray the dinit stream onto the back surface of the substrate 1.

At this time, if the dinit stream is sprayed at a position corresponding to the mounting position of the electronic component 3 or a group of electronic components 3, the electronic component 3
Needless to say, cooling is carried out efficiently.

In addition, in the one shown in FIG. 2, the nozzle 6 is provided only on one side of the isobaric container 5, but the nozzle 6 is provided on both sides.
The dinit flow may be sprayed onto two substrates 1 using two headers.

The one shown in FIG. 3 has an adiabatic expansion mechanism 8 provided at the air chamber or the air supply port of the distributor 10, and is otherwise the same as the one shown in FIG. 2.

The one shown in FIG. 4 has a heat exchanger 13 added to the one shown in FIG. 2. As is well known, when air is compressed, its temperature increases, and the heat exchanger 13 radiates the heat of the increased temperature to the surroundings. Some pressure difference? When air is cooled by adiabatic expansion above, constant relative humidity? It is known that the humid air above becomes supercooled and the moisture in the air condenses.

If you want to avoid blowing condensed moisture-containing air onto the electronic components 3 as a dinit flow, the air should be kept at a constant temperature above the intake air temperature during cooling by adiabatic expansion. It is necessary to prevent it from falling downward. As mentioned earlier, the temperature change due to adiabatic expansion depends on the pressure difference or the air volume ratio, so in order to prevent the air from becoming a certain temperature below the intake air temperature, for example, the adiabatic expansion valve should be throttled or the nozzle should be opened. All you have to do is adjust the relationship between diameter and pressure. As is clear from the explanation on the sphere, the cooling method for the electronic device of the present invention is as follows:
(b) The dinit flow provides a heat transfer coefficient comparable to that of liquid cooling, which is close to the limit value of air cooling, (b) It is possible to intensively cool locally heated parts such as semiconductor chips, and (c) In the liquid cooling system, No special refrigerant required (
d) Since the cooling system can be separated from the board, only the board can be taken out, resulting in excellent maintainability; (
(e) The rise in air temperature inside the rack can be ignored and all parts can be cooled with air at a temperature lower than room temperature due to adiabatic expansion; (f) The above can also be installed in a relatively high temperature atmosphere; (g) These As a result, it has excellent effects such as being able to allow a higher packaging density than conventional air cooling, and (g) being able to make the overall configuration more compact.

In addition,? Although the above has mainly described an example in which air is used as the refrigerant, it is of course possible to use other gases as the refrigerant.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a conventional cooling system for electronic equipment, Fig. 2 is a block diagram of the first embodiment of the present invention, Fig. 3 is a block diagram of the second embodiment of the present invention, and Fig. 4 is a diagram of the present invention. FIG. 5, a block diagram of the third embodiment of the invention, is a diagram showing the relationship between a board on which electronic components are mounted and a dinit header. 1... Board, 3... Electronic components, 4...
...Ginnit Hezda, 5...Isobaric container,
6... Dinit jet nozzle, 7... Air introduction pipe, 8... Adiabatic expansion mechanism, 9...
- Air piping, 10... air chamber or distributor, 11... air compressor or prower, 12... pressure gauge, 13... heat exchanger.

Claims (1)

[Claims] 1. An electronic device configured by mounting a plurality of electronic components on a substrate and having a surface parallel to the surface of the substrate, and an isobaric container provided with a plurality of jet stream ejection nozzles. a jet header, a piping system for supplying compressed air or compressed gas to the jet header, and a mechanism for generating adiabatic expansion provided in the piping system, and the jet header is connected to a substrate of the electronic device. and the jet stream ejected from each of the plurality of jet stream ejection nozzles of the jet header is arranged such that the free jet flow part of the jet stream has a vertical component with respect to the surface of the substrate, A cooling method for an electronic device, characterized in that the air is sprayed onto a locally heated portion of the electronic device. 2. The electronic device according to claim 1, wherein the piping system includes piping, an air chamber or distributor, and a compressor, and the air supply port of the air chamber or distributor has a throttle function. cooling method. 3. A cooling method for an electronic device according to claim 1 or 2, characterized in that the air supply port of the jet header has a throttle function. 4. The cooling method according to claim 1, wherein the conditions for causing adiabatic expansion are adjusted so that the temperature of the air cooled as a result of adiabatic expansion does not fall below a certain temperature below the intake air temperature. 5. The electronic device according to any one of claims 1 to 4, wherein the piping system has a heat exchanger that radiates heat to the surroundings from a temperature increase in air or gas that occurs during pressurization. Equipment cooling method.