WO2011114616A1

WO2011114616A1 - Ebullient cooling device

Info

Publication number: WO2011114616A1
Application number: PCT/JP2011/000667
Authority: WO
Inventors: 聡針生; 康二吉原; 雄一朗友野
Original assignee: 株式会社豊田自動織機
Priority date: 2010-03-19
Filing date: 2011-02-07
Publication date: 2011-09-22
Also published as: JP2011196632A

Abstract

Disclosed is a ebullient cooling device capable of improving heat exchange efficiency, and which allows the division of the liquid and gas components of a refrigerant in the condensing unit (30). The disclosed ebullient cooling device is provided with a housing unit housing a liquid refrigerant, and a condensing unit which forms an inner space, one end of which communicates with a communicating chamber, and the other end of which is sealed, and in which the bottom end of the communicating chamber side of the inner space is lower than the bottom end of the sealed side thereof. In the inner space of the condensing unit, multiple fins extending from one to the other lateral surface in the condensing unit are arranged in a row from the communicating chamber side toward the sealed side, and, at least for those of the multiple fins nearest the communicating chamber, the distance (a) between the top of the fins and the top surface in the condensing unit is greater than the distance (b) between the bottom of the fins and the bottom surface in the condensing unit, and the cross-section area of the passage above the fins on the side nearest the communicating chamber is greater than cross-section area of the passage below the fins on the side nearest the communicating chamber.

Description

Boiling cooler

The present invention relates to a boiling cooling device that cools a heating element using a refrigerant.

The boiling cooling device is a device that cools the heating element using latent heat generated when the liquid refrigerant boils. The boiling cooling device includes an accommodating portion that accommodates a liquid refrigerant. The refrigerant (vapor refrigerant) boiled by the heat of the heating element in this housing portion flows into the condenser, where it is heat-exchanged and condensed. The condensed liquid refrigerant circulates again to the storage unit. Such a boiling cooling device is described in, for example, Japanese Patent Laid-Open No. 10-173115 (Patent Document 1).

Recently, from the viewpoint of downsizing and improvement of condensation performance, a condenser is provided on the upper side of the housing portion. If it is this structure, the liquid refrigerant condensed in the condenser will flow through the bottom face in a condenser, and will circulate to an accommodating part. In the case where the condensed liquid refrigerant is dropped directly into the housing portion as in the conventional case, if the width of the condenser is increased in order to increase the condensation performance of the condenser, the width of the housing portion must be increased accordingly. The device becomes large. The structure which arrange | positions a condenser to the upper part side of an accommodating part can change the magnitude | size of a condenser, without changing the magnitude | size of an accommodating part, and becomes an advantageous structure at the point of size reduction and a condensation performance improvement.

JP-A-10-173115

However, in the above configuration, in the internal space of the condenser, the vapor refrigerant and the liquid refrigerant are mixed, and the inflow of the vapor refrigerant into the condenser and the outflow of the liquid refrigerant into the storage portion are not necessarily performed efficiently. It wasn't.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a boiling cooling device that enables a gas-liquid split in a condensing section and improves heat exchange efficiency.

The boiling cooling device of the present invention accommodates a liquid refrigerant that boils by receiving heat from a heating element, a housing part having a communication chamber above the refrigerant liquid level, one end communicating with the communication chamber, and the other end closed. A condensing unit that forms an internal space, and the lower end on the side of the communication chamber in the inner space is located below the lower end on the closed side, wherein the condensing unit is provided in the inner space of the condensing unit. A plurality of fin portions extending from one side surface to the other side surface are arranged in parallel from the communication chamber side to the closing side, and at least the fin portion on the communication chamber side among the plurality of fin portions is the fin portion. The distance between the upper end portion and the inner upper surface of the condensing portion is larger than the distance between the lower end portion of the fin portion and the inner lower surface of the condensing portion, and the passage cross-sectional area above the fin portion closest to the communication chamber is Of the fin portion closest to the communication chamber It is larger than the passage cross-sectional area of square.

According to the present invention, in the inclined condensing part, the distance between the upper end part of the fin part and the inner upper surface of the condensing part (hereinafter also referred to as “upper distance”) is between the lower end part of the fin part and the inner lower surface of the condensing part. The opening area of the upper surface side passage (hereinafter also referred to as “upper passage”) that is larger than the distance (hereinafter also referred to as “lower distance”) and is partitioned by the fin portion in the internal space of the condensing portion is the lower surface side passage (hereinafter referred to as “lower passage”). It is larger than the opening area of the “lower passage”.

Thereby, the inflow resistance of the upper passage becomes smaller than that of the lower passage, and the vapor refrigerant becomes easier to flow into the upper passage than in the lower passage. Further, in the lower passage, the above action suppresses the disturbance due to the inflow of the vapor refrigerant with respect to the flow of the liquid refrigerant flowing on the inner lower surface (bottom surface) and flowing out to the accommodating portion. According to this, the vapor refrigerant mainly circulates in the upper passage, and the liquid refrigerant mainly circulates in the lower passage. That is, in the boiling cooling device of the present invention, the gas-liquid can be divided in the condensing part. Thereby, the refrigerant circulation is good and the heat exchange efficiency can be improved.

Here, it is preferable that the fin portion is arranged so as to extend in the vertical direction. A plurality of small passages are formed in the vertical direction by the plurality of fin portions, and the upper passage and the lower passage are communicated by the small passages. Since the small passage is partitioned by the fin portion, the passage has high heat transfer performance. And the said small channel | path is formed also in the communicating chamber side by arranging the fin part extended in the up-down direction in parallel. That is, the inflowing vapor refrigerant can be introduced into a small passage having a high heat transfer performance over a short distance, and heat exchange efficiency can be improved.

Here, it is preferable that the upper distance is larger than the lower distance for all the fin portions. Thereby, the passage cross-sectional area of the upper passage is larger than that of the lower passage, and the resistance of the entire upper passage to the vapor refrigerant can be reduced. Therefore, the vapor refrigerant is more likely to flow into the upper passage.

Here, the plurality of fin portions are preferably formed of corrugated fins whose corrugated tops are joined to the inner side surface of the condensing unit. Since a plurality of fin portions are formed only by installing one corrugated fin inside, manufacturing is facilitated. In addition, the heat transfer area with the refrigerant can be reliably increased.

Here, the condensing part is preferably made of a tube member closed on one side. In addition to being easy to manufacture, the condensing part can be made compact (downsized). Furthermore, the boiling cooling device of the present invention may include a plurality of condensing units. Moreover, it is preferable that adjacent condensing parts are connected with the outer fin arrange | positioned between adjacent condensing parts. It is compact and can improve the condensation performance efficiently.

According to the boiling cooling device of the present invention, the gas-liquid can be divided in the condensing part, and the heat exchange efficiency can be improved.

1 is a perspective view showing a boiling cooling device 1. FIG. 1 is a longitudinal sectional view showing a boiling cooling device 1. FIG. 3 is a cross-sectional view taken along line AA showing the condensing unit 30. FIG. 3 is a cross-sectional view taken along line BB showing the condensing unit 30. FIG. 1 is a longitudinal sectional view showing a boiling cooling device 10. FIG. 5 is a cross-sectional view taken along the line CC showing the condensing unit 30. FIG. FIG. 6 is a cross-sectional view taken along line CC showing another aspect of the condensing unit 30. FIG. 6 is a cross-sectional view taken along line CC showing another aspect of the condensing unit 30. 3 is a cross-sectional view corresponding to a cross-sectional view taken along line AA showing the condensing unit 30. FIG. 1 is a longitudinal sectional view showing a boiling cooling device 100. FIG.

Next, the present invention will be described in more detail with reference to embodiments.

<First embodiment>
A boiling cooling device 1 according to a first embodiment will be described with reference to FIGS. FIG. 1 is a perspective view showing a boiling cooling device 1. FIG. 2 is a longitudinal sectional view showing the boiling cooling device 1. FIG. 3 is a cross-sectional view taken along the line AA showing the condensing unit 30. FIG. 4 is a cross-sectional view taken along the line BB showing the condensing unit 30.

As shown in FIG. 1, the boiling cooling device 1 includes a housing portion 2 and a condenser 3. The accommodating part 2 is a metal container that accommodates a liquid refrigerant (for example, water, alcohol, chlorofluorocarbon, etc.) therein, and has a container part 21 and a communication part 22. The container portion 21 is a bottomed rectangular tube-shaped container having an opening in the upper portion, and stores a liquid refrigerant therein. The liquid level of the liquid refrigerant is located in the container portion 21 when the boiling cooling device 1 is stopped. A heating element Z is attached to the outer side surface of the container part 21, and the side surface of the container part 21 transfers the heat of the heating element Z, and heat exchange is performed with the internal liquid refrigerant. The heating element Z is, for example, a power module including a semiconductor element or the like.

The communication part 22 has a substantially hollow cylindrical shape and is located above the container part 21. The internal space of the communication part 22 communicates with the internal space of the container part 21. A communication chamber 2 a that communicates with the internal space of the condensing unit 3 is formed in the internal space above the liquid level in the storage unit 2 (in the communication unit 22 and the upper part in the container unit 21). In addition, the shape of the accommodating part 2 is not restricted above. For example, the communication part 22 may have a planar shape in which the left wall in FIG. 2 extends vertically or a rectangular cross-sectional shape.

The condenser 3 includes a plurality of condensing units 30 and outer fins 301 that connect the condensing units 30. The condensing unit 30 includes a case unit 31 and a plurality of fin units 32. The case portion 31 is formed of a flat cylindrical metal member having one end opened and the other end closed. As shown in FIG. 3, the distance c between the inner side surfaces of the case portion 31 is substantially constant in the vertical direction. The opening end of the case portion 31 is joined to the communication portion 22. The internal space of the case part 31 leads to the communication chamber 2a. As for case part 31, the opening side lower end (communication chamber 2a side lower end) in internal space is located below the closure side lower end. That is, the inner bottom surface (corresponding to the “inner lower surface” of the present invention) of the case portion 31 is inclined so as to be higher as it goes from the open end to the closed end. In the present embodiment, the inner bottom surface and the inner upper surface of the condensing unit 30 are substantially parallel. The case portion 31 is composed of two parts. After a fin portion 32 (to be described later) is joined (welded or the like) to one side surface of the case portion 31, the one side surface member and the other side surface member of the case portion 31 are joined. Formed.

The fin portion 32 is formed of a plate-like metal member (for example, aluminum) having a high thermal conductivity. The fin portion 32 is installed in the case portion 31 so as to extend from one side surface inside the case portion 31 to the other side surface. Specifically, left and right end portions (left and right end portions in FIG. 3) of the fin portion 32 are respectively joined to the inner side surface of the case portion 31. In addition, as for the fin part 32, only one edge part of the right-and-left end part of the fin part 32 is joined to the internal side surface of the case part 31, and the other edge part does not contact the internal side surface of the case part 31 (it does not reach). It may be a size. The fin portion 32 is disposed so that one surface thereof intersects the direction from the open end of the case portion 31 toward the closed end (hereinafter also referred to as “longitudinal direction”). In the present embodiment, the fin portion 32 is disposed so that the one surface is substantially orthogonal to the longitudinal direction. By the fin part 32, the heat transfer area with the refrigerant | coolant vapor | steam in the condensation part 30 increases.

The plurality of fin portions 32 are arranged in parallel at intervals in the longitudinal direction of the condensing portion 30. As shown in FIGS. 3 and 4, the fin portion 32 extends in the vertical direction, and a small passage 30 c extending in the vertical direction is formed between the opposing fin portions 32. In all of the plurality of fin portions 32, the distance a between the upper end portion of the fin portion 32 and the inner upper surface of the case portion 31 is larger than the distance b between the lower end portion of the fin portion 32 and the inner bottom surface of the case portion 31. (A> b).

The internal space of the case portion 31 is divided into an upper passage 30a, a lower passage 30b, and a plurality of small passages 30c by a plurality of fin portions 32. The upper passage 30 a is a passage formed above the fin portion 32 and extends along the inner upper surface of the case portion 31 from the open end to the closed end of the case portion 31. The lower passage 30b is a passage formed below the fin portion 32 and extends along the inner bottom surface of the case portion 31 from the open end to the closed end of the case portion 31. The small passage 30c is a passage extending vertically to communicate the upper passage 30a and the lower passage 30b.

Here, the effect of the boiling cooling device 1 will be described. The heat of the heating element Z is transmitted to the liquid refrigerant through the side surface of the container portion 21 to boil the liquid refrigerant. The boiling vapor refrigerant rises as bubbles and flows out into the communication chamber 2a. Thereafter, the vapor refrigerant rises and flows into the condensing unit 30 from the communication chamber 2 a in the communication unit 22. The vapor refrigerant that has flowed into the condensing unit 30 is cooled (heat exchanged) there and condensed to become a liquid refrigerant. The condensed liquid refrigerant flows on the inner bottom surface of the condensing unit 30, flows out into the communication chamber 2 a, and then circulates in the container unit 21.

In the present embodiment, first, the fin portion 32 closest to the communication chamber 2a is arranged such that the distance a is larger than the distance b. For this reason, in the condensing part 30, the opening area of the upper channel | path 30a is larger than the opening area of the lower channel | path 30b. That is, the inflow resistance of the vapor refrigerant to the upper passage 30a is smaller than the inflow resistance to the lower passage 30b. Accordingly, the vapor refrigerant easily flows into the upper passage 30a when flowing into the condensing unit 30 from the communication chamber 2a.

Furthermore, in the present embodiment, all the fin portions 32 are arranged in a relationship of a> b, and the passage sectional area of the upper passage 30a is larger than the passage sectional area of the lower passage 30b. Thereby, in the whole condensing part 30, the flow resistance becomes smaller in the upper passage 30a than in the lower passage 30b. The vapor refrigerant flowing into the communication chamber 2a mainly flows into the upper passage 30a.

The vapor refrigerant that has flowed into the upper passage 30a proceeds toward the closed end in the condensing unit 30 and also flows into the small passage 30c. The vapor refrigerant transfers heat to the wall surfaces of the fin portion 32 and the case portion 31 and is condensed to become a liquid refrigerant. The vapor refrigerant is mainly condensed in the small passage 30 c including the heat transfer surface of the fin portion 32. The condensed liquid refrigerant flows out to the lower passage 30b through the small passage 30c, and flows out to the communication chamber 2a through the lower passage 30b. Vapor refrigerant hardly flows from the communication chamber 2a into the lower passage 30b, and mainly condensed liquid refrigerant flows.

Thus, according to the present embodiment, the vapor refrigerant mainly circulates in the upper passage 30a and the liquid refrigerant circulates in the lower passage 30b. That is, in the boiling cooling device 1, the gas-liquid splitting of the refrigerant is possible in the condensing unit 30. Thereby, the refrigerant | coolant can be efficiently distribute | circulated through the condensation part 30, and heat exchange efficiency can be improved. Furthermore, in this embodiment, since the internal space is partitioned by the fin part 32 that increases the heat transfer area, the heat exchange efficiency can be improved by the synergistic effect of the gas-liquid split flow and the heat transfer area increase.

Further, since the plurality of small passages 30a are arranged in parallel, the turbulent flow of the vapor refrigerant easily occurs in the upper passage 30a. When the turbulent flow of the vapor refrigerant occurs, heat exchange with the wall surfaces of the fin portion 32 and the case portion 31 is promoted, and the heat exchange efficiency of the condensing portion 30 is improved, which is advantageous. Further, by forming the small passage 30c so as to extend in the vertical direction, the small passage 30a (that is, a passage having high condensation performance) can be formed on the vapor refrigerant inflow side (opening end side of the case portion 31). Thereby, a vapor refrigerant can be condensed with a short distribution distance, and condensation efficiency can be improved. Moreover, since the opening area of the upper channel | path 30a can be adjusted only by changing the position of the fin part 32, manufacture or preparation is easy.

Further, the configuration in which the plurality of small passages 30c communicate with the lower passage 30b as in the present embodiment can improve the condensing performance and reduce the portion (container portion 21) that accommodates the liquid refrigerant. Thereby, the mounting property to a vehicle etc. improves, and it is advantageous also in mounting property.

Thus, according to the boiling cooling device 1 of the present embodiment, it is possible to make a gas-liquid flow in the condensing unit 30 and to improve the heat exchange efficiency.

<Second embodiment>
The boiling cooling device 10 of the second embodiment is obtained by changing the condensing unit of the first embodiment, and the other components are denoted by the same reference numerals and description thereof is omitted. The second embodiment will be described below with reference to FIGS. FIG. 5 is a longitudinal sectional view showing the boiling cooling device 10. FIG. 6 is a cross-sectional view taken along the line CC showing the condensing unit 30. FIG. 7 is a cross-sectional view taken along line CC showing another aspect of the condensing unit 30. FIG. 8 is a cross-sectional view taken along line CC showing another aspect of the condensing unit 30. FIG. 9 is a cross-sectional view corresponding to the cross-sectional view taken along the line AA showing the condensing unit 30.

As shown in FIG. 5, the condensing unit 30 includes a case unit 31 and corrugated fins 33. Case part 31 consists of a metal tube member with one end closed. A corrugated fin 33 to be described later is inserted and fixed in the case portion 31.

The corrugated fins 33 are formed by forming a thin metal plate (for example, aluminum or the like) having a high heat transfer rate into a wave shape by alternately bending at a predetermined pitch. As shown in FIG. 6, the top of the corrugated fin 33 is joined to the inner side surface of the case 31. That is, the corrugated fin 33 includes a plurality of fin portions 331 extending from one side surface inside the case portion 31 to the other side surface. The fin part 331 is extended in the up-down direction like 1st embodiment. That is, like the first embodiment, the small passage 30c extends in the vertical direction.

The corrugated fins 33 are arranged in the case portion 31 so that all the fin portions 331 satisfy a> b. Thereby, also in 2nd embodiment, the effect similar to 1st embodiment is exhibited. Furthermore, in the second embodiment, it is only necessary to install one fin (corrugated fin 33) in which a plurality of fin portions 331 are formed in the case portion 31, and the manufacture of the condensing portion 30 becomes extremely easy. Moreover, since the tube member is used for the case part 31, the condensation part 30 and the condenser 3 can be manufactured easily and compactly. The corrugated fins 33 are not limited to the above shape. For example, as shown in FIG. 7, the corrugated fins 33 may be bent into a square shape.

Further, the plurality of fin portions 32 (331) may not be separate from the case portion 31, and may be dimple fins as shown in FIG. This is formed by arranging a plurality of concave portions in parallel on one side wall of the case portion 31.

Further, the inner side surface distance (the lateral width of the inner space corresponding to c in the first embodiment) of the case portion 31 is not limited to a constant value, and may be vertically symmetric as shown in FIG. That is, the width of the internal space of the condensing unit 30 (the distance between the inner side surfaces) may be symmetrical in the vertical direction or substantially constant in the vertical direction. In this case, if the distance a between the upper end portion of the fin portion 32 (331) and the inner upper surface of the condensing portion 3 is larger than the distance b between the lower end portion of the fin portion 32 (331) and the inner bottom surface of the condensing portion 3. The passage sectional area of the upper passage 30a is always larger than the passage sectional area of the lower passage 30b. However, even if the inner side surface distance of the case portion 31 is not constant or symmetrical in the vertical direction, the passage cross-sectional area of the upper passage 30a can be changed to the passage cross-sectional area of the lower passage 30b by making the distance a larger than the distance b. It only needs to be larger than.

<Third embodiment>
The boiling cooling device 100 of the third embodiment is obtained by changing the housing portion of the second embodiment, and the other components are denoted by the same reference numerals and description thereof is omitted. FIG. 10 is a longitudinal sectional view showing the boiling cooling device 100.

As shown in FIG. 10, the accommodating portion 2 has a partition wall portion 23 in the container portion 21. The partition wall portion 23 is a plate-like member and is disposed to face the side wall of the container portion 21 to which the heating element Z is attached. The partition wall part 23 partitions the internal space of the container part 21 into a boiling passage X and a reflux passage Y. The partition wall portion 23 is joined to the inner side surface of the container portion 21, but is not joined to the inner bottom surface of the container portion 21. For this reason, the boiling passage X and the reflux passage Y are connected downward. The upper end of the partition wall portion 23 is located in the communication portion 22.

The boiling passage X is a space surrounded by the inner side surface, the inner bottom surface, and the partition wall portion 23 of the container portion 21 and is a region on the heating element Z arrangement side (left side in FIG. 10). The boiling passage X extends in the vertical direction, communicates with the communication chamber 2a at the upper end and communicates with the circulation passage Y at the lower end. The boiling passage X is a passage through which the vapor refrigerant boiled by heat received from the side wall to which the heating element Z is attached flows out into the communication chamber 2a.

The circulation path Y is a space surrounded by the inner side surface, the inner bottom surface, and the partition wall portion 23 of the container portion 21, and is a region on the side where the heating element Z is not disposed (right side in FIG. 10). The circulation passage Y extends in the vertical direction, communicates with the communication chamber 2a at the upper end, and communicates with the boiling passage X at the lower end. The circulation passage Y is a passage through which liquid refrigerant condensed in the condensing unit 30 flows from the upper end and supplies the liquid refrigerant to the boiling passage X from the lower end. The liquid refrigerant flows from the circulation passage Y toward the boiling passage X by its own weight (see arrow in FIG. 10). The condenser 3 is attached to the opposite side (right side in FIG. 10) to the heating element Z (left side in FIG. 10). Therefore, the circulation passage Y is formed on the side where the heating element Z is not arranged, that is, the side where the condensing part 30 is arranged.

According to the boiling cooling device 100 of the third embodiment, the gas-liquid flow of the refrigerant can be performed in the condensing unit 30 as in the second embodiment. Further, a boiling passage X through which the vapor refrigerant passes and a circulation passage Y through which the liquid refrigerant circulates are formed in the container portion 21. Since the reflux passage Y is located closer to the opening side of the condensing unit 30 than the boiling passage X, the liquid refrigerant that has flowed out of the condensing unit 30 (lower passage 30b) flows into the circulation passage Y. Moreover, since the upper end of the partition wall part 23 is located in the communicating part 22, the vapor refrigerant is more likely to flow into the upper passage 30a instead of the lower passage 30b. That is, according to the boiling cooling device 100 of the third embodiment, a large flow of the refrigerant can be formed in the entire boiling cooling device 100 as shown by the arrows in FIG. Thereby, a refrigerant | coolant can circulate through the boiling cooling device 100 efficiently and smoothly, and can improve heat exchange efficiency in the accommodating part 2 synergistically. The fin portion 331 may be the fin portion 32 of the first embodiment.

The fin portion 32 (331) is opposed to the condensing portion 3 in the horizontal direction when the cross-sectional shape (cross section orthogonal to the longitudinal direction) of the condensing portion 3 (case portion 31) is circular or elliptical. Of the two inner wall surfaces, it may be formed so as to extend from one inner wall surface toward the other inner wall surface. In other words, the “one side surface” inside the condensing unit includes one inner wall surface that faces in the horizontal direction in the condensing unit 3, and the “other side surface” faces the one inner wall surface in the condensing unit 3. The other inner wall surface is included. In this case, the inner upper surface is a line connecting the upper ends of the cross-sectional shape of the condensing part 3, and the inner lower surface is a line connecting the lower ends of the cross-sectional area.

1, 10, 100: boiling cooling device,
2: storage part, 21: container part, 22: communication part, 2a: communication room, 23: partition wall part,
3: Condenser, 30: Condensing part, 31: Case part, 32, 331: Fin part,
33: Corrugated fin,
30a: upper passage, 30b: lower passage, 30c: small passage,
X: Boiling passage, Y: Circulation passage, Z: Heating element

Claims

A liquid refrigerant that boils by receiving heat from the heating element is housed, and a housing part that has a communication chamber above the liquid surface of the refrigerant,
A condensing part in which one end communicates with the communication chamber and the other end is closed to form an internal space, and the communication chamber side lower end in the internal space is located below the closed side lower end;
A boiling cooling device comprising:
In the internal space of the condensing unit, a plurality of fins extending from one side surface to the other side surface inside the condensing unit are arranged in parallel from the communication chamber side to the closing side,
Among the plurality of fin portions, at least the fin portion on the side of the communication chamber has a distance between the upper end portion of the fin portion and the inner upper surface of the condensing portion, and the lower end portion of the fin portion and the inner lower surface of the condensing portion. And a passage cross-sectional area above the fin portion closest to the communication chamber is larger than a cross-sectional area below the fin portion closest to the communication chamber.
The boiling cooling device according to claim 1, wherein the fin portion is arranged to extend in a vertical direction.
In all the fin portions of the plurality of fin portions, the distance between the upper end portion of the fin portion and the inner upper surface of the condensing portion is larger than the distance between the lower end portion of the fin portion and the inner lower surface of the condensing portion. Item 3. The boiling cooling device according to Item 1 or 2.
The boiling cooling device according to any one of claims 1 to 3, wherein the plurality of fin portions are wavy fins whose corrugated top portions are joined to the inner side surface of the condensing portion.
The boiling cooling device according to any one of claims 1 to 4, wherein the condensing part is made of a tube member closed at one end.
The boiling cooling device according to any one of claims 1 to 5, comprising a plurality of the condensing units.
The boiling cooling device according to claim 6, wherein the plurality of condensing units are connected to each other by an outer fin disposed between the condensing units adjacent to each other.