WO2017082127A1

WO2017082127A1 - Electronic equipment cooling device

Info

Publication number: WO2017082127A1
Application number: PCT/JP2016/082509
Authority: WO
Inventors: 松田　和也
Original assignee: 株式会社日立製作所
Priority date: 2015-11-10
Filing date: 2016-11-02
Publication date: 2017-05-18
Also published as: JP2019024028A

Abstract

Provided is an electronic equipment cooling device which is capable of circulating refrigerant by utilizing capillary force and with small pressure loss, and which is small and has a high cooling capacity. The electronic equipment cooling device is provided with: a boiling unit which cools a heat-generating member by vaporizing an internally enclosed liquid refrigerant, and which has a boiling unit exit via which vaporized gas refrigerant flows out; a condensation unit which condenses the vaporized refrigerant; a liquid reservoir unit which is disposed around the boiling unit and in which liquid refrigerant condensed by the condensation unit is accumulated; a gas pipe connecting the boiling unit exit and an entrance in an upper part of the condensation unit; and a liquid pipe connecting a lower part of the condensation unit and the liquid reservoir unit. The boiling unit is fitted with a plurality of fine flow passageways connecting the liquid reservoir unit and the boiling unit exit, wherein the fine flow passageways are configured so as to be inclined with the exit side thereof positioned higher than the entrance side thereof, and configured to cause the liquid refrigerant in the liquid reservoir unit to rise through the fine flow passageways by the capillary force of the fine flow passageways.

Description

Electronic equipment cooling device

The present invention relates to a cooling device for an electronic apparatus having therein a semiconductor device which is a high heat generating element such as a central processing unit (CPU) or a power conversion element.

In recent years, electronic devices and power conversion devices have been reduced in size and density, and the heat generation density has increased. Semiconductor devices such as CPUs and power conversion elements used in these devices generate heat during operation, but their performance may be degraded or damaged when they exceed a predetermined temperature. Therefore, it is necessary to cool an electronic device that generates heat to a predetermined temperature or lower. In addition, with the downsizing of the entire apparatus having electronic devices, cooling devices for cooling electronic devices that generate heat are also required to be downsized and have improved cooling capacity.

As a conventional cooling device for electronic equipment, for example, there is a cooling device for a power converter that uses air or water as a refrigerant and uses a sensible heat difference (temperature difference) of the refrigerant. In such a cooling device using the sensible heat difference of the refrigerant, a refrigerant having a low temperature up to the part of the electronic device that generates heat by using external power such as a fan or a pump or natural convection for transporting the refrigerant. The electronic equipment is cooled by exchanging heat and exchanging heat with the high-temperature electronic equipment generating heat.

With the improvement of heat generation density, the cooling device using sensible heat has a problem of insufficient cooling capacity and an increase in the size of the cooling device. For this reason, in recent years, a cooling device that has a higher cooling capacity and uses latent heat at the time of phase change of the refrigerant has been used. In general, latent heat is larger than sensible heat, and since there is no temperature rise during phase change, a large amount of heat can be transferred from the heating element to the refrigerant even if the temperature difference between the refrigerant and the heating element is small. High efficiency can be achieved.

As a cooling device using this latent heat, for example, there is one described in JP 2011-47616 A (Patent Document 1). In this Patent Document 1, in the heat receiving jacket, the refrigerant is vaporized by exchanging heat with the heating element, and flows to the condenser via the header provided above, and the vaporized refrigerant is condensed again by this condenser. Then, a gravity-type cooling system for electronic devices is described that is configured to return to the heat receiving jacket via a liquid return pipe by the gravity of the condensed liquid refrigerant.

In this patent document 1, since external power such as a pump is not used for transporting the refrigerant, it is possible to provide a cooling device with further reduced power consumption, and as a result, low power consumption of an electronic device equipped with the cooling device. Can be realized.

Another conventional cooling device using latent heat is described in Japanese Patent Application Laid-Open No. 2004-190976 (Patent Document 2). In this patent document 2, an electronic device that circulates a refrigerant by using a capillary wick structure provided with a wick structure that generates a capillary force without using the gravity of the liquid refrigerant to circulate the refrigerant. A cooling device is described.

JP 2011-47616 A JP 2004-190976 A

In the gravity-type cooling device that circulates the refrigerant by the gravity of the liquid refrigerant as described in the above-mentioned Patent Document 1, in order to circulate the refrigerant, the condenser is compared with the liquid level of the liquid refrigerant in the heat receiving jacket. The liquid height of the liquid refrigerant in must be increased. That is, the liquid refrigerant condensed in the condenser flows into the heat receiving jacket, vaporizes, and the liquid level in the condenser is the liquid loss in the heat receiving jacket by the pressure loss necessary for returning to the condenser again. It must be higher than the liquid level of the refrigerant. For this reason, the cooling device of an electronic device has the subject to enlarge in a height direction.

Further, in the cooling device that circulates the refrigerant using the capillary force described in Patent Document 2, it is not necessary to provide a difference in the level of the refrigerant liquid as in Patent Document 1, but the evaporator Therefore, the wick has a two-phase flow in which the liquid refrigerant and the vaporized refrigerant coexist. For this reason, the pressure loss by a flow becomes large in the wick, and as a result, the flow of the refrigerant is hindered and there is a problem that the heat transfer capability is lowered.

An object of the present invention is to obtain a cooling device for an electronic device that can circulate a refrigerant with a small pressure loss while utilizing a capillary force and that is small in size and has a high cooling capacity.

In order to achieve the above object, the present invention vaporizes the liquid refrigerant sealed inside to cool the heating element, condenses the boiling part having a boiling part outlet through which the vaporized gas refrigerant flows, and the vaporized refrigerant. A condensing unit, a liquid storage unit that is provided around the boiling unit and stores the liquid refrigerant condensed in the condensing unit, a gas pipe connecting the boiling unit outlet and the upper inlet of the condensing unit, and the condensing unit A liquid pipe that connects the lower part of the liquid part and the liquid reservoir part, and the boiling part is provided with a plurality of fine flow paths that connect the liquid reservoir part and the boiling part outlet, and the fine flow path Is configured to be inclined so that the outlet side is higher than the inlet side, and the liquid refrigerant in the liquid reservoir is configured to rise in the fine flow path by the capillary force of the fine flow path. It is in the cooling device for electronic equipment.

Another feature of the present invention is that the liquid refrigerant sealed inside is vaporized to cool the heating element, and the boiling part has a boiling part outlet through which the vaporized gas refrigerant flows out, and the condensing part condenses the vaporized refrigerant. A liquid reservoir portion that is provided around the boiling portion and stores the liquid refrigerant condensed in the condensing portion; a gas pipe that connects the boiling portion outlet and the upper inlet of the condensing portion; and a lower portion of the condensing portion And a liquid pipe connecting the liquid reservoir, the boiling portion is provided with a plurality of fine flow paths connecting the liquid reservoir and the outlet of the boiling portion, and the fine flow path is Cooling of electronic equipment configured to have a continuous shape with a constant flow path area from the inlet side to the outlet side, and to allow the liquid refrigerant in the liquid reservoir to flow into the fine flow path by the capillary force of the fine flow path In the device.

According to the present invention, it is possible to circulate the refrigerant with a small pressure loss while utilizing the capillary force, and to obtain an electronic device cooling apparatus having a small size and a high cooling capacity.

It is a perspective view of the cooling device of the electronic device which shows Example 1 of this invention. It is a top sectional view showing a boiling part and a liquid reservoir shown in Drawing 1, and is a figure showing a section along a portion of a fine passage. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. It is the A section enlarged view of FIG. It is sectional drawing explaining the flow of the refrigerant | coolant in case the fine flow path shown in FIG. 3 is a rectangle. It is sectional drawing explaining the flow of a refrigerant | coolant in case the microchannel shown in FIG. 3 is circular. It is a perspective view of the cooling device of the electronic device which shows Example 2 of this invention. FIG. 8 is a plan cross-sectional view showing the boiling portion and the liquid reservoir shown in FIG. 7, and shows a cross section along the portion of the fine passage. It is a side view of the boiling part explaining Example 3 of this invention. It is a perspective view of the cooling device of the electronic device which shows Example 4 of this invention.

Hereinafter, specific examples of the electronic apparatus cooling apparatus according to the present invention will be described with reference to the drawings. In each figure, the part which attached | subjected the same code | symbol has shown the part which is the same or it corresponds.

A first embodiment of the electronic apparatus cooling apparatus according to the present invention will be described with reference to FIGS.
First, the overall configuration of the first embodiment will be described with reference to FIG. FIG. 1 is a perspective view of a cooling apparatus for an electronic apparatus according to the first embodiment.

In FIG. 1, the cooling device 1 includes a boiling unit 2, a condensing unit 3, a liquid storage unit 4, a liquid pipe 5, a gas pipe 6, and the like. Arrow g is the direction of gravity.
The boiling section 2 is connected to the liquid reservoir section 4 and the gas pipe 6 so that the refrigerant can flow while the inside is sealed. Further, the heat generating element 7 is thermally connected to the heat generating element 7 such as a semiconductor element, and the heat generated by the heat generating element 7 is transmitted to the refrigerant flowing through the boiling portion 2 to cool the heat generating element 7. ing.

The gas pipe 6 is connected to the boiling unit 2 and the condensing unit 3 so that the refrigerant can flow in a sealed state. The gas pipe 6 preferably has a larger pipe diameter than the liquid pipe 5 because the refrigerant that has been vaporized and expanded by boiling mainly flows inside the gas pipe 6. In the present embodiment, the gas pipe 6 is a circular pipe, but other pipe shapes such as an elliptical pipe or a square pipe may be used.

The condensing unit 3 is connected to the gas pipe 6 and the liquid pipe 5 so that the refrigerant can flow in a state where the inside is sealed. In the condensing unit 3, the gas refrigerant flowing from the gas pipe 6 is recondensed. Therefore, the material of the condensing part 3 should have a high thermal conductivity, and is made of, for example, copper or aluminum.

The liquid pipe 5 is connected to the condensing unit 3 and the liquid storage unit 4 and can flow the refrigerant in a state where the inside is sealed. In the present embodiment, the liquid pipe 5 is connected horizontally from the condensing part 3 to the liquid storage part 4, but may be connected obliquely. By connecting the liquid pipe 5 so that the outlet side (liquid reservoir 4 side) is lower than the inlet side (condenser 3 side), the gravity of the liquid refrigerant can be used for transporting the liquid refrigerant. The liquid can be sent to the liquid reservoir 4 more smoothly. The cross-sectional shape of the liquid pipe 5 is a circular pipe, similar to the gas pipe 6, but is not limited to a circular pipe, and may be other pipe shapes such as an elliptical pipe or a square pipe. Also good.

The liquid reservoir 4 is connected to the liquid pipe 5 and the boiling part 2 so that the refrigerant can flow in a state where the inside is sealed. The liquid reservoir 4 stores liquid refrigerant recondensed in the condensing unit 3.

The heating element 7 is a CPU, a power conversion element or the like and serves as a heat source. The heating element 7 is thermally connected to the boiling part 2, and heat generated by the heating element 7 is transmitted to the boiling part 2. That is, the heating element 7 and the boiling part 2 are in direct contact with each other or are connected via a sheet or grease having a high thermal conductivity, and further, the heating element 7 is connected by a screw (not shown) or the like. Since the cooling device 1 is fixed to the surroundings, heat resistance can be reduced and heat can be efficiently transferred to the cooling device 1.

A coolant is injected into the cooling device 1 from a coolant inlet (not shown). Thereafter, the pressure inside the cooling device 1 is adjusted to a predetermined pressure, and the refrigerant inlet is sealed. Since the temperature at which the refrigerant evaporates is determined by the type of refrigerant and the saturated vapor pressure, after the refrigerant inlet is sealed so that the saturated vapor pressure inside the cooling device 1 does not change, the outside air and the refrigerant are brought into the cooling device 1. It is necessary to prevent transmission. For this reason, the material of the part through which the refrigerant flows in the cooling device 1 is preferably a metal material with a small gas permeation.
Moreover, the refrigerant | coolant should just be a thing which a gas-liquid phase change occurs at the use temperature of the said heat generating body 7, and the pressure-reduced water and a fluorocarbon refrigerant are suitable.

Next, the structure of the boiling part 2 in this embodiment will be described with reference to FIGS. 2 is a cross-sectional plan view showing the boiling section 2 and the liquid reservoir 4 shown in FIG. 1, showing a cross section along the portion of the fine passage 22, and FIG. 3 is a cross-sectional view taken along the line III-III in FIG. FIG. 4 is an enlarged view of part A of FIG.

As shown in FIG. 2 and FIG. 3, the boiling part 2 includes a disk-shaped member 2a, a boiling part outlet (center of the boiling part) 21 provided at the center upper part of the disk-shaped member 2a, and the disk-shaped member. In order to connect the outer peripheral side of the member 2 a and the boiling part outlet 21, a plurality of fine flow paths 22 provided radially from the outer peripheral side of the disk-shaped member 2 a toward the boiling part outlet 21 are provided. Further, the fine channel 22 is configured in a continuous shape having a constant channel area from the inlet side to the outlet side, that is, a shape that is not intermittent.

On the outer peripheral side of the disk-shaped member 2a, a liquid reservoir 4 formed in an annular shape (doughnut shape) is provided along the outer peripheral side of the disk-shaped member 2a. The liquid reservoir 4 is formed in an annular member 4a provided along the outer periphery of the disk-shaped member 2a, and the liquid refrigerant flowing from the liquid pipe 5 is stored. Therefore, the fine flow path 22 is provided so as to connect the liquid reservoir 4 and the boiling part outlet 21, and the liquid refrigerant in the liquid reservoir 4 is made fine by the capillary force of the fine passage 22. It is configured to flow into the passage 22.

As shown in FIG. 3, the boiling part outlet 21 is disposed at a position higher than the liquid reservoir 4, and the fine channel 22 of the boiling part 2 has one end as shown in FIG. The side is open to the liquid reservoir 4 and the other end is open to the boiling part outlet 21. Therefore, the fine channel 22 is formed in an inclined structure so as to rise from the liquid reservoir 4 provided on the outer peripheral side toward the boiling part outlet 21. Further, as shown in FIG. 2, a large number of the fine flow paths 22 are formed in the circumferential direction of the disk-like member 2 a, and the many fine flow paths 22 are joined at the boiling portion center 21. Yes. Accordingly, a large number of the fine passages 22 are provided radially from the boiling portion center 21 to the entire outer periphery of the disk-like member 2a. In addition, the said boiling part exit 21 is connected with the said gas piping 6 (refer FIG. 1).

As described above, the fine channel 22 is formed so that the outlet side is higher than the inlet side. The inlet side of the fine channel 22 is connected to the liquid reservoir 4 and is made of liquid refrigerant. be satisfied. For this reason, the liquid refrigerant on the inlet side of the fine channel 22 flows to the outlet 221 of the fine channel 22 by capillary force as shown in FIG. Since the boiling part center 21 has a larger cross-sectional area than the fine flow path 22, the capillary force is reduced. Therefore, the liquid refrigerant is transported from the liquid reservoir 4 to the position of the outlet 221 of the fine channel.

The cross-sectional shape of the fine channel 22 is not limited as long as the liquid refrigerant can be transported by a capillary force, and is preferably square or circular in consideration of ease of manufacture.
5 is a cross-sectional view for explaining the flow of the refrigerant when the fine flow path 22 shown in FIG. 3 is a square, and FIG. 6 is a cross-sectional view for explaining the flow of the refrigerant when the fine flow path 22 shown in FIG. is there. The flow state of the refrigerant flowing through the fine flow path 22 in each cross-sectional shape will be compared and described with reference to FIGS. 5 and 6.

The liquid refrigerant flowing in the fine flow path 22 is gasified by heat from the heating element 7 (see FIG. 3). For this reason, as shown in FIGS. 5 and 6, the inside of the fine flow path 22 is a two-phase flow of gasified gas refrigerant and non-gasified liquid refrigerant, and the gas refrigerant is a cross section of the fine flow path 22. The liquid refrigerant flows in the form of a film around the outer periphery. When the cross-sectional shape of the fine channel 22 is a quadrangle, the liquid refrigerant has a large film thickness near the corners of the quadrangle indicated by arrows in FIG. Since this thick portion is generated, even when the local heat generation amount in the heat generating portion 7 is instantaneously increased, the liquid refrigerant is prevented from being insufficient due to the thick portion of the liquid film. Can continue to evaporate. Therefore, an effect of stably cooling the heat generating portion 7 is obtained.

In the rectangular fine channel 22 shown in FIG. 5, the upper two corners and the lower two corners are configured to be at the same height position. You may comprise so that it may arrange | position diagonally, ie, it may become a rhombus shape so that the uppermost part and another one corner | angular part may become the lowest part.

On the other hand, as shown in FIG. 6, when the cross section of the fine channel 22 is circular, the liquid refrigerant is distributed around the gas refrigerant with a substantially uniform thickness. Therefore, when the fine flow path 22 is formed in a circular shape, the heat from the heating element 7 can be uniformly transmitted to the liquid refrigerant from the entire outer periphery of the circular fine passage 22.
As the material of the boiling part 2, since it is necessary to efficiently transfer the heat from the heating element 7 to the refrigerant, it is preferable to use a material having a high thermal conductivity such as copper or aluminum.

Next, the operation of the electronic apparatus cooling apparatus 1 according to this embodiment will be described with reference to FIG.
When liquid refrigerant is stored in the liquid reservoir 4, the liquid refrigerant flows from the liquid reservoir 4 into the microchannel 22 of the boiling unit 2 by capillary force, and further, the microchannel 22. The liquid refrigerant is accumulated up to the outlet 221 (see FIG. 4). When heat from the heating element 7 is transmitted to the boiling part 2 in a state where the liquid refrigerant is accumulated in the fine flow path 22, the fine flow path 22 is heated and the wall surface of the heated fine flow path 22 is heated. Heat is transferred from the liquid refrigerant to the liquid refrigerant. As a result, the liquid refrigerant in the microchannel 22 boils and gasifies, and a large amount of gas slag (gas-liquid two-layer flow appears in the microchannel 22 as shown in FIGS. 5 and 6). Gas) is generated and flows as a slag flow.

In the fine flow path 22, the liquid refrigerant that has not boiled moves to the tube wall surface side of the fine flow path 22 to form a liquid film. Since the fine channel 22 is inclined in the height direction toward the boiling part outlet 21, the gas slag flows toward the boiling part outlet 21 by buoyancy.

Thus, when a slag flow flows through the fine flow path 22, a force due to buoyancy acts, so that the pressure loss between the inlet and the outlet of the fine flow path 22 can be reduced. Moreover, since the liquid film around the slag flow becomes very thin as the slag flow flows through the fine flow path 22, heat transfer to the liquid refrigerant flowing through the fine flow path 22 is improved. Thereby, the heat from the said heat generating body 7 can be more efficiently transmitted to a liquid refrigerant.

In order to improve heat transfer to the liquid refrigerant flowing through the fine channel 22, when the fine channel 22 is circular, the diameter is preferably 0.5 to 0.1 mm. When the fine channel 22 is not circular, the hydraulic equivalent diameter may be 0.5 to 0.1 mm.

The gas refrigerant that has flowed from the boiling part outlet 21 to the gas pipe 6 shown in FIG. 1 flows into the condensing part 3 to be condensed and becomes liquid refrigerant again. In this embodiment, air having a temperature lower than the condensation temperature of the refrigerant is blown from the fan (not shown) to the condensing unit 3 in the direction of the arrow indicated by Air in FIG. Heat exchange is performed between the gas refrigerant and the air, and the gas refrigerant is cooled and condensed.

Generally, since the thermal conductivity of air is small, fins 31 are provided on the air side of the condensing unit 3 for the purpose of increasing the heat transfer area and the heat transfer coefficient. In this embodiment, the ventilation direction of the air by the fan is directed from the condensing unit 3 to the boiling unit 2, but the ventilation direction is appropriately changed according to the electronic device on which the cooling device 1 is mounted. Anyway. For example, the condensing unit 3 is disposed on the back side of the paper with respect to the boiling unit 2, and the gas pipe 6 and the liquid pipe 5 are also configured to face the back side of the paper in FIG. The same effect can be obtained even if a fan is provided to ventilate the air.

In the first embodiment, the condensing unit 3 is cooled with external air. However, the condensing unit 3 may be cooled with cold water, or may be cooled with a cold heat source such as a Peltier element or a refrigeration cycle.

The liquid refrigerant condensed in the condensing unit 3 flows from the lower part of the condensing unit 3 into the liquid storing unit 4 through the liquid pipe 5 and is stored again in the liquid storing unit 4. repeat.
In addition, the lower end of the condensing unit 3 is provided at a position higher than the upper end of the liquid storing unit 4 so that the liquid refrigerant smoothly flows from the condensing unit 3 to the liquid storing unit 4.

The material of the annular member 4a forming the liquid pipe 5 and the liquid reservoir 4 is such that the condensed liquid refrigerant is transferred to the liquid pipe 5 or the liquid reservoir by heat conduction from the outside air or the heating element 7. In order to prevent boiling inside the portion 4, it is preferable to use a material having a relatively low thermal conductivity, such as stainless steel.

According to the first embodiment described above, there is no need for a height difference as high as the liquid level required in the gravity type cooling device that circulates the refrigerant by the gravity of the liquid refrigerant described in Patent Document 1 described above. Further, it is possible to prevent the cooling device of the electronic device from increasing in size in the height direction, and the effect of further reducing the size of the cooling device can be obtained.

Further, since the fine flow path 22 is formed in the boiling part 2 radially around the boiling part outlet 21, more fine flow paths 22 can be provided. This increases the capillary force for guiding the liquid refrigerant to the fine flow path. Accordingly, even when the amount of heat generated from the heating element 7 is large, the liquid refrigerant is filled in the fine flow path by the capillary force, and the heating element 7 can be cooled. From this point, the cooling capacity can be improved. .

Further, since the fine flow path 22 is inclined so as to rise from the liquid reservoir 4 toward the boiling part center 21, the buoyancy of the gas slag generated by boiling in the fine flow path 22, Naturally, the refrigerant can flow toward the gas pipe 6. As a result, the pressure loss due to the flow of the refrigerant that is a gas-liquid two-phase flow can be greatly reduced as compared with a cooling device that circulates the refrigerant using capillary force as described in Patent Document 2 above. The flow of the refrigerant is not hindered, and the effect of improving the heat transfer capability is also obtained. In addition, the heat transfer to the refrigerant in the fine flow path 22 can be obtained by a heat transfer in a liquid film using a slag flow in addition to boiling, so that a cooling device for a small electronic device having a high cooling capacity can be obtained.

Example 2 of the electronic apparatus cooling apparatus of the present invention will be described with reference to FIGS. FIG. 7 is a perspective view of a cooling device for an electronic device showing the second embodiment, and FIG. FIG. In the description of the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, the description thereof will be omitted, and different parts will be mainly described.

As shown in FIGS. 7 and 8, in the second embodiment, the shape of the boiling portion 2 having a plurality of fine flow paths 22 is not a circular shape as shown in the first embodiment, but a square shape. It is what you are doing. The liquid reservoir 4 is also formed along the outer periphery of the boiling portion 2 so as to be square according to the shape of the square boiling portion 2. That is, the boiling part 2 includes a rectangular plate-like member 2b, a plurality of fine channels 22 formed in the rectangular plate-like member 2b, and a boiling part outlet (boiling) provided at the center of the plate-like member 2b. Part center) 21. A square annular member 4a is provided around the square plate-like member 2b, and a liquid reservoir 4 is formed in the annular member 4a. A large number of the fine flow paths 22 are provided radially from the outer peripheral side of the plate-like member 2b toward the boiling part outlet so as to connect the liquid reservoir 4 and the boiling part outlet 21.

In general, since the heating element 7 has a square shape, by making the boiling part 2 square as in the present embodiment, the entire boiling part 2 can be brought into contact with the rectangular heating element 7 in contact therewith. The entire boiling portion 2 can be effectively used for cooling the heating element 7. That is, it is possible to further reduce the portion of the boiling portion 2 that does not contribute to the cooling of the heating element 7.

Moreover, as shown in FIG. 8, since the boiling part 2 has a quadrangular shape, the flow path lengths of the fine flow paths 22 provided in the circumferential direction are different depending on the respective inlet positions. . In the second embodiment, all the microchannels 22 provided in the circumferential direction have the same diameter (the same hydraulic equivalent diameter when the cross section of the microchannel is not circular), but the length of the microchannel 22 Accordingly, it is also possible to adjust the capillary force by changing the diameter of each fine channel 22 or the hydraulic equivalent diameter.

That is, by reducing the diameter or hydraulic equivalent diameter of the fine flow path 22 having a long flow path so that the liquid refrigerant is filled up to the outlet 221 (see FIG. 4) of all the fine flow paths 22. The capillary force is adjusted so as to increase, and in the case of the fine channel 22 with a short channel, the diameter or the hydraulic equivalent diameter is increased. Other configurations are the same as those of the first embodiment.

According to the present embodiment, the shape of the boiling part 2 is also made square with respect to the general rectangular heating element 7, so that the heat transfer surface of the boiling part 2 can be used effectively, and highly efficient electrons. Equipment cooling devices can be obtained.

Embodiment 3 of the electronic apparatus cooling apparatus of the present invention will be described with reference to FIG. FIG. 9 is a side view of the boiling part 2 for explaining the third embodiment of the present invention, and the fine pipes 22 are indicated by broken lines. Also in the description of the third embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, the description thereof will be omitted, and different parts will be mainly described. FIG. 9 shows only the boiling part 2, but the other configuration is the same as that of the first embodiment.

As shown in FIG. 9, in the present Example 3, it is the same as that of the said Example 1 in the point that the boiling part 2 is circular, and it is the same also in the point that many fine flow paths 22 are provided in the circumferential direction. . The third embodiment is different from the first embodiment in that two types of fine channels 22 formed in the boiling portion 2 are provided, that is, an upper layer fine channel 223 and a lower layer fine channel 224.

The openings (inlet side openings) to the liquid reservoir 4 (see FIG. 2) in each fine channel 22 (223, 224) are equally spaced in the circumferential direction and the same height as shown in FIG. In the position.
Further, the outlet side of the upper layer fine channel 223 opens to the position of the upper part 21a of the boiling part outlet 21, and the outlet side of the lower layer fine channel 224 opens to the position of the lower part 21b of the boiling part outlet 21. ing. Further, as shown in FIG. 9, the upper microchannel 223 and the lower microchannel 224 are alternately provided in the circumferential direction.

As described above, the upper microchannel 223 and the lower microchannel 224 have the same inlet height but different outlet heights. Therefore, the upper microchannel 223 and the lower microchannel 224 have a channel. Are different, and the upper fine flow path 223 is longer. In each fine channel 22, the liquid refrigerant must be filled to the outlet side, that is, to the boiling portion center 21 side by capillary force. Therefore, it is preferable to adjust the capillary force of the upper microchannel 223 to be larger by making the diameter of the upper microchannel 223 or the hydraulic equivalent diameter smaller than that of the lower microchannel 224. Thus, also in the present embodiment, the capillary force can be appropriately adjusted by changing the diameter of the fine flow path 22 or the hydraulic equivalent diameter as in the second embodiment.

By the way, in the thing of the said Example 1, if the number of the microchannels 22 is increased, the space | interval of the entrance side of a microchannel can fully be ensured, but the space | interval of the exit side of a microchannel becomes small, and it adjoins. If the outlet sides of the fine channel 22 to be joined together, the hydraulic equivalent diameter at the outlet of the fine channel 22 increases, and the capillary force does not work. For this reason, in order not to unite the exit sides of the adjacent microchannels 22, the number of the microchannels 22 cannot be increased by a certain number or more.
On the other hand, by adopting a configuration in which the height of the outlet of the fine channel 22 is changed as in the third example, for example, the number of the fine channels 22 is doubled with respect to that of the first example. It becomes possible to make it.

When the heat generation amount of the heating element 7 (see FIG. 1) is large, a dry-out phenomenon may occur in which all the liquid refrigerant in the fine flow path 22 is vaporized. When this dry-out phenomenon occurs, the liquid refrigerant disappears in the fine flow path 22, and the heating element 7 cannot be cooled to an appropriate temperature.

In the third embodiment, the microchannel 22 is multi-layered into two layers of an upper layer microchannel 223 and a lower layer microchannel 224, so that the inlet side of each microchannel 22 overlaps the adjacent microchannel 22 with the adjacent one. As long as this is not the case, the number of fine channels can be increased. As a result, the occurrence of the dry-out phenomenon can be prevented, and even when the amount of heat generated by the heating element 7 is large, it can be sufficiently cooled.

In the third embodiment, the example in which the microchannel 22 is provided with two types of the upper microchannel 223 and the lower microchannel 224 has been described. However, the microchannel 22 has three or more layers in the vertical direction of the boiling portion outlet 21. Three or more kinds of fine flow paths may be provided in each. Other configurations and effects are the same as those of the first embodiment.

Embodiment 4 of the electronic apparatus cooling apparatus according to the present invention will be described with reference to FIG. FIG. 10 is a perspective view of the electronic apparatus cooling apparatus according to the fourth embodiment, and shows another example of the boiling unit 2. Also in the description of the fourth embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, the description thereof is omitted, and different parts are mainly described.

In Example 4, a plurality of boiling parts are provided, a boiling part outlet is provided at the center upper part of each boiling part, and a liquid reservoir is provided at a position lower than the boiling part outlet around the boiling part. A large number of fine flow paths are provided radially so as to connect these liquid reservoirs and the boiling part outlet.

That is, as shown in FIG. 10, the boiling part 2 is constituted by an upper boiling part 24 and a lower boiling part 25, and the heating element 7 is cooled by the two upper and lower boiling parts 24,25. The boiling parts 24 and 25 are formed in a quadrangular shape, and the U-shaped liquid reservoir 4 (upper liquid reservoir 44, lower side) extends along the lower surface and the two side surfaces of the boiling parts 24 and 25. A liquid reservoir 45) is provided. Further, an upper boiling portion outlet 21 </ b> A and a lower boiling portion outlet 21 </ b> B are provided at the center upper portions of the upper boiling portion 24 and the lower boiling portion 25 at positions higher than the liquid reservoir 4, respectively.

In the upper boiling part 24 and the lower boiling part 25, a large number of fine flow paths 22 are provided radially so as to connect the liquid reservoirs 44, 45 and the boiling

part outlets

21A, 21B. That is, the fine flow paths 22 are provided radially so as to rise from the upper liquid reservoir 44 and the lower liquid reservoir 45 toward the gas pipe 6.

Further, since the upper liquid reservoir 44 and the lower liquid reservoir 45 need to be filled with the liquid refrigerant, the liquid level of the liquid refrigerant condensed in the condensing unit 3 is the liquid pipe 5. It is configured to exist at least above the inner liquid level 51.

In this embodiment, the heating element 7 and the boiling parts 24 and 25 are provided in a direction parallel to the direction of gravity indicated by the arrow g. Therefore, the refrigerant vaporized in the fine flow path 22 of each of the boiling parts 24 and 25 becomes a slag flow, and moves to the gas pipe 6 by receiving buoyancy in the direction opposite to gravity. Temporarily, as shown in the said Example 1, what formed the fine flow path 22 radially toward the boiling part exit 21 from the outer periphery of the boiling part 2 as shown in FIG. If it arrange | positions in a parallel direction, the fine flow path 22 located above the boiling part exit 21 will be made. In the microchannel 22 positioned above, a phenomenon occurs in which the slag flow in which the refrigerant is vaporized flows backward to the inlet side of the microchannel 22.

On the other hand, with the configuration as in the fourth embodiment, the upper liquid reservoir 44 and the lower liquid reservoir 45 flow into the fine flow path 22 in the upper boiling portion 24 and the lower boiling portion 25. The flow direction of the refrigerant is from the horizontal to the upper direction in any fine channel 22. Therefore, it is possible to prevent the slag flow generated in the fine flow path 22 and rising due to buoyancy from flowing back to the liquid reservoirs 44 and 45. Other configurations are the same as those of the first embodiment.

According to the fourth embodiment, since the boiling part 2 is composed of a plurality of boiling parts 2 (upper boiling part 24, lower boiling part 25) arranged one above the other, the cooling capacity can be further increased. In addition, it is possible to cope with a long heating element 7, and it is also possible to cool a plurality of heating elements 7. In addition, since it is possible to provide more fine flow paths 22, the capillary force for guiding the liquid refrigerant to the fine flow paths is increased. Accordingly, even when the amount of heat generated from the heating element 7 is large, the liquid refrigerant is filled in the fine flow path by the capillary force, and the heating element 7 can be cooled. From this point, the cooling capacity can be improved. .

In the present embodiment, two boiling parts 2 and two liquid storage parts 4 are arranged on the upper side and the lower side. However, the present invention is not limited to two. Depending on the capillary force of 22, it is possible to increase the number of divisions (the number of boiling parts 2 and liquid reservoirs 4). It is necessary to increase the number of branches of the liquid pipe 5 and the gas pipe 6 according to the number of divisions.

In addition, although the example in which the boiling portion 2 is configured in a quadrangular shape has been described, it may be a semicircular shape. Furthermore, in the present Example 4, although the some boiling part 2 and the liquid storage part 4 were set as the structure arrange | positioned up and down, it is good also as a structure which arrange | positions the several boiling part 2 and the liquid storage part 4 on right and left.

In addition, this invention is not limited to the Example mentioned above, Various modifications are included. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment.
Further, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described.

1: cooling device,
2: boiling part, 2a: disk-shaped member, 2b: plate-shaped member,
21: Boiling part exit (boiling part center), 21a: upper part, 21b: lower part,
21A: Upper boiling part outlet, 21B: Lower boiling part outlet,
22: Fine flow path (fine pipe line), 221: Exit of fine flow path,
223: Upper microchannel, 224: Lower microchannel,
24: Upper boiling part, 25: Lower boiling part,
3: Condensing part, 31: Fin,
4: liquid reservoir, 4a: annular member, 44: upper liquid reservoir, 45: lower liquid reservoir,
5: Liquid piping, 51: Liquid level height of liquid piping,
6: Gas piping, 7: Heating element.

Claims

A boiling part having a boiling part outlet through which the liquid refrigerant sealed inside is vaporized to cool the heating element and the vaporized gas refrigerant flows out,
A condensing part for condensing the vaporized refrigerant;
A liquid reservoir that is provided around the boiling portion and stores the liquid refrigerant condensed in the condenser;
A gas pipe connecting the boiling part outlet and the inlet at the top of the condensing part;
A liquid pipe connecting the lower part of the condensing unit and the liquid reservoir,
The boiling section is provided with a plurality of fine flow paths connecting the liquid reservoir section and the boiling section outlet, and the fine flow paths are inclined so that the outlet side is higher than the inlet side. A cooling apparatus for electronic equipment, characterized in that the liquid refrigerant in the liquid reservoir is raised in the fine flow path by the capillary force of the fine flow path.
In the cooling device of the electronic device of Claim 1,
The electronic apparatus cooling apparatus according to claim 1, wherein a diameter of the fine flow path or a hydraulic equivalent diameter of the boiling portion is 0.5 to 0.1 mm.
In the cooling device of the electronic device of Claim 1,
The boiling part includes a disk-shaped member, and the boiling part outlet is provided at the center of the disk-shaped member, and the fine flow path is directed from the outer peripheral side of the disk-shaped member toward the boiling part outlet. A cooling device for electronic equipment, characterized by being formed radially.
In the cooling device of the electronic device of Claim 1,
The boiling portion includes a rectangular plate-like member, the boiling portion outlet is provided at the center of the plate-like member, and the fine flow path is directed from the outer peripheral side of the plate-like member toward the boiling portion outlet. A cooling device for electronic equipment, characterized by being formed radially.
In the cooling device of the electronic device according to claim 4,
An electronic device cooling apparatus characterized in that a fine flow path with a long flow path has a smaller diameter or a hydraulic equivalent diameter than a fine flow path with a short flow path.
In the cooling device of the electronic device of Claim 1,
The fine flow path provided in the boiling part is composed of an upper fine flow path whose outlet side is connected to the upper part of the boiling part outlet and a lower fine flow path connected to the lower part of the boiling part outlet. A cooling device for electronic equipment.
In the cooling device of the electronic device of Claim 1,
A plurality of the boiling parts are provided, a boiling part outlet is provided at the center upper part of each boiling part, and a liquid reservoir is provided at a position lower than the boiling part outlet around the boiling part. A cooling device for electronic equipment, wherein a plurality of fine flow paths are provided radially so as to connect the part and the boiling part outlet.
In the cooling device of the electronic device of Claim 1,
The boiling part is composed of an upper boiling part and a lower boiling part, and the boiling part is formed in a square shape, and a U-shaped liquid reservoir so as to be along the lower surface and two side surfaces of each boiling part. The upper boiling part outlet and the lower boiling part outlet are provided at positions higher than the liquid reservoir at the center upper part of the upper boiling part and the lower boiling part, respectively, and the upper boiling part and A cooling device for electronic equipment, wherein a plurality of fine flow paths are provided radially in the lower boiling portion so as to connect the liquid reservoir and the outlet of the boiling portion.
A boiling part having a boiling part outlet through which the liquid refrigerant sealed inside is vaporized to cool the heating element and the vaporized gas refrigerant flows out,
A condensing part for condensing the vaporized refrigerant;
A liquid reservoir that is provided around the boiling portion and stores the liquid refrigerant condensed in the condenser;
A gas pipe connecting the boiling part outlet and the inlet at the top of the condensing part;
A liquid pipe connecting the lower part of the condensing unit and the liquid reservoir,
The boiling portion is provided with a plurality of fine flow paths connecting the liquid reservoir portion and the boiling portion outlet, and the fine flow passage has a continuous shape with a constant flow passage area from the inlet side to the outlet side. An electronic device cooling apparatus, characterized in that the liquid refrigerant in the liquid reservoir is configured to flow into the fine flow path by the capillary force of the fine flow path.