Boiling cooling device

Abstract

To provide an evaporative cooling device capable of suppressing deterioration of cooling efficiency.SOLUTION: An evaporative cooling device includes: a heat receiving part storing a refrigerant, and receiving heat from a heating element; a heat radiating part for radiating the heat from the heat receiving part; a first pipe for transferring a gas-phase refrigerant generated by vaporizing the refrigerant in the heat receiving part to the heat radiation part; and a second pipe for transferring a liquid-phase refrigerant generated by condensing the gas-phase refrigerant in the heat radiating part to the heat receiving part. The heat receiving part has a heat transfer surface which is brought into contact with the liquid refrigerant, and the heat transfer surface has a first portion producing nuclear boiling of the refrigerant, and a second portion hardly producing nuclear boiling of the refrigerant compared to the first portion. The second pipe has a first opening opened toward the heat receiving part, and a second opening opened toward the heat radiating part. The first opening is positioned below a liquid level of the refrigerant stored in the heat receiving part, and a distance between the first opening and the first portion is shorter than a distance between the first opening and the second portion.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a boiling cooling device. [Background technology]

[0002] 2. Description of the Related Art A boiling cooling device is known that cools a heat-generating body by utilizing heat transport due to latent heat caused by boiling of a refrigerant.

[0003] The cooling device described in Patent Document 1 has a heat receiving section, a heat dissipating section, and a steam pipe and a liquid pipe connecting them. The heat receiving section is a container for storing a refrigerant, and receives heat from an object to be cooled, vaporizing the refrigerant by the heat. The steam pipe transports the refrigerant vaporized in the heat receiving section to the heat dissipating section. The heat dissipating section condenses and liquefies the refrigerant by dissipating heat from the refrigerant. The liquid pipe transports the refrigerant condensed and liquefied in the heat dissipating section to the heat receiving section. Here, a steam outlet and a liquid inlet are provided on the side of the container of the heat receiving section. A steam pipe is connected to the steam outlet. A liquid pipe is connected to the liquid inlet. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2015 / 146110 Summary of the Invention [Problem to be solved by the invention]

[0005] The cooling device described in Patent Document 1 has a problem in that bubbles generated by nucleate boiling of the refrigerant in the heat receiving section get into the liquid inlet, hindering the circulation of the refrigerant, resulting in a decrease in cooling performance. [Means for solving the problem]

[0006] In order to solve the above problems, the boil cooling device according to the first aspect of the present invention includes a heat receiving section that accommodates a refrigerant and receives heat from a heat generating element, a heat dissipation section that dissipates heat from the heat receiving section, a first pipe section that transports a gas phase refrigerant generated by vaporizing the refrigerant in the heat receiving section to the heat dissipation section, and a second pipe section that transports a liquid phase refrigerant generated by condensing the gas phase refrigerant in the heat dissipation section to the heat receiving section, the heat receiving section having a heat transfer surface that contacts a liquid refrigerant to be vaporized by heat from the heat generating element, the heat transfer surface having a first portion that causes nucleate boiling of the refrigerant and a second portion that is less likely to cause nucleate boiling of the refrigerant than the first portion, the second pipe section having a first opening that opens toward the heat receiving section and a second opening that opens toward the heat dissipation section, the first opening is located below the liquid level of the refrigerant accommodated in the heat receiving section, and the distance between the first opening and the first portion is shorter than the distance between the first opening and the second portion.

[0007] In addition, a boiling cooling device according to a second aspect of the present invention includes a heat receiving section that accommodates a refrigerant and receives heat from a heat generating element, a heat dissipation section that dissipates heat from the heat receiving section, a first pipe section that transports a gas phase refrigerant generated by evaporation of the refrigerant in the heat receiving section to the heat dissipation section, and a second pipe section that transports a liquid phase refrigerant generated by condensing the gas phase refrigerant in the heat dissipation section to the heat receiving section, wherein the heat receiving section has a heat transfer surface that contacts the liquid refrigerant to be evaporated by heat from the heating element, and the heat transfer surface has a first portion that causes nucleate boiling of the refrigerant and a second portion that is less likely to cause nucleate boiling of the refrigerant than the first portion, and the second pipe section has a first opening that opens toward the heat receiving section and a second opening that opens toward the heat dissipation section, wherein the first opening is located below the liquid level of the refrigerant accommodated in the heat receiving section, and each of the first opening and the second portion is located below the first portion.

[0008] Further, a boil cooling device according to a third aspect of the present invention includes a heat receiving section that accommodates a refrigerant and receives heat from a heat generating body, a heat dissipating section that dissipates heat from the heat receiving section, a first pipe section that transports a gas phase refrigerant generated by vaporizing the refrigerant in the heat receiving section to the heat dissipating section, and a second pipe section that transports a liquid phase refrigerant generated by condensing the gas phase refrigerant in the heat dissipating section to the heat receiving section, wherein the heat receiving section has a heat transfer surface that comes into contact with the liquid refrigerant to be vaporized by heat from the heat generating body, and the heat transfer surface causes nucleate boiling of the refrigerant. The second pipe portion has a first opening that opens toward the heat receiving portion and a second opening that opens toward the heat dissipation portion, the first opening is located below the liquid level of the refrigerant contained in the heat receiving portion, the first and second portions are provided at different positions in the horizontal direction below the first opening, the first portion does not overlap the first opening when viewed in the vertical direction, and the second portion overlaps the first opening when viewed in the vertical direction. [Brief description of the drawings]

[0009] [Figure 1] 1 is a perspective view showing a schematic configuration of a boil cooling device according to a first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of the boil cooling device shown in FIG. [Diagram 3] 3 is a cross-sectional view taken along line AA in FIG. 2. [Figure 4] FIG. 6 is a cross-sectional view of a boil cooling device according to a second embodiment. [Diagram 5] FIG. 11 is a cross-sectional view of a boil cooling device according to a third embodiment. [Figure 6] FIG. 11 is a cross-sectional view of a boil cooling device according to a fourth embodiment. [Figure 7] FIG. 11 is a cross-sectional view of a boil cooling device according to a fifth embodiment. [Figure 8] FIG. 1 is a perspective view showing an application example of a boiling cooling device. [Figure 9] FIG. 11 is a cross-sectional view of a boil cooling device according to a first modified example. [Figure 10] FIG. 11 is a cross-sectional view of a boil cooling device according to a second modified example. [Figure 11] FIG. 11 is a cross-sectional view of a boil cooling device according to a third modified example. [Figure 12] FIG. 11 is a cross-sectional view of a boil cooling device according to a fourth modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Note that the dimensions and scale of each part in the drawings may differ from the actual dimensions and some parts are shown diagrammatically to facilitate understanding. Furthermore, the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description to the effect that the present invention is limited thereto.

[0011] 1. First embodiment 1-1. Overview of boiling cooling device FIG. 1 is a perspective view showing a schematic configuration of a boil cooling device 1 according to a first embodiment. In the following description, for convenience, an X-axis, a Y-axis, and a Z-axis that are perpendicular to each other are appropriately used. In addition, in the following description, one direction along the X-axis is the X1 direction, and the direction opposite to the X1 direction is the X2 direction. One direction along the Y-axis is the Y1 direction, and the direction opposite to the Y1 direction is the Y2 direction. One direction along the Z-axis is the Z1 direction, and the direction opposite to the Z1 direction is the Z2 direction.

[0012] Typically, the Z axis is a vertical line, the Z1 direction corresponds to the vertical upward direction, and the Z2 direction corresponds to the vertical downward direction. The direction of the Z axis in real space is determined according to the installation posture of the boiling cooling device 1. The Z axis may be inclined within a range of 45° or less with respect to the vertical line. In the following, the term "upper" simply refers to a position in a direction along the vertical line, and includes both the vertical upward direction and the vertical diagonally upward direction as a concept. Similarly, the term "lower" simply refers to a position in a direction along the vertical line, and includes both the vertical downward direction and the vertical diagonally downward direction as a concept.

[0013] The boiling cooling device 1 cools two heating elements 100 indicated by two-dot chain lines in Fig. 1. Each heating element 100 is, for example, a power semiconductor element such as a diode or an IGBT (Insulated Gate Bipolar Transistor). The power semiconductor element is mounted in a power electronics product such as an inverter or rectifier mounted in, for example, a railroad car, an automobile, or a household electric machine.

[0014] In the example shown in FIG. 1, each heating element 100 has a flat shape along the XZ plane. The two heating elements 100 are arranged side by side in the direction along the Y axis so as to sandwich the boil cooling device 1. FIG. 1 shows the outline of the heating element 100. The shape of the heating element 100 is not limited to the example shown in FIG. 1, but is arbitrary. One of the two heating elements 100 may be omitted. The heating element 100 is not limited to a power semiconductor element, and may be any other electric or electronic component that generates heat by being driven or energized, etc., as long as it requires cooling.

[0015] The boiling cooling device 1 is a loop-type thermosiphon cooler that utilizes the density difference between a vaporized refrigerant RE and a liquefied refrigerant RE. The boiling cooling device 1 has a heat receiving section 10, a heat dissipating section 20, a first pipe section 30, and a second pipe section 40.

[0016] In the heat receiving section 10, the refrigerant RE is heated by the heat from the heating element 100, and the refrigerant RE is vaporized to generate a gas-phase refrigerant. The gas-phase refrigerant rises through the first pipe section 30 due to a decrease in density, and is transported to the heat dissipation section 20. In the heat dissipation section 20, the gas-phase refrigerant is cooled by heat dissipation, and the gas-phase refrigerant is condensed to generate a liquid-phase refrigerant. The liquid-phase refrigerant falls through the second pipe section 40 due to an increase in density, and is transported to the heat receiving section 10. In this way, the refrigerant RE from the heat receiving section 10 is circulated in the order of the first pipe section 30, the heat dissipation section 20, the second pipe section 40, and the heat receiving section 10 due to the density difference between the vaporized refrigerant RE and the liquefied refrigerant RE, and the heating element 100 is cooled. Each part of the boiling cooling device 1 will be described in order below.

[0017] 1-2. Components of the boiling cooling device Fig. 2 is a cross-sectional view of the boil cooling device 1 shown in Fig. 1. Fig. 3 is a cross-sectional view taken along line AA in Fig. 2. Fig. 2 shows a cross-section of the boil cooling device 1 cut along a plane including the X-axis and the Z-axis. Fig. 3 also shows a cross-section of the heat receiving part 10 cut along a plane including the X-axis and the Y-axis.

[0018] 1-2a. Heat receiving part The heat receiving section 10 is a structure having an accommodation chamber S10, and receives heat from the heat generating element 100. The accommodation chamber S10 is a space that accommodates a liquid refrigerant RE to be vaporized by the heat from the heat generating element 100. In the heat receiving section 10, the refrigerant RE is vaporized by the heat of the heat generating element 100, thereby generating a gas-phase refrigerant.

[0019] The refrigerant RE is not particularly limited, but examples thereof include water-based refrigerants such as water, alcohol-based refrigerants such as methanol, ketone-based refrigerants such as acetone, glycol-based refrigerants such as ethylene glycol, fluorocarbon-based refrigerants such as Fluorinert, fluorocarbon-based refrigerants such as HFC134a, and hydrocarbon-based refrigerants such as butane. If necessary, a surfactant such as a fluorine-based surfactant, a silicone-based surfactant, or a hydrocarbon-based surfactant may be added to the refrigerant RE. The refrigerant RE may also be a combination of two or more of the above-mentioned refrigerants.

[0020] 2, the heat receiving portion 10 is a box-shaped container having an accommodation chamber S10 as an internal space. The heat receiving portion 10 includes a bottom plate 11, a top plate 12, a side wall 13, and a heat transfer member 14.

[0021] Each of the bottom plate 11 and the top plate 12 is a flat plate extending in a direction perpendicular to the Z axis. However, the top plate 12 is located in the Z1 direction relative to the bottom plate 11, and the top plate 12 is provided with holes for connection to the first tube section 30 and the second tube section 40. The bottom plate 11 and the top plate 12 are arranged parallel to each other, and a side wall 13 is arranged between them.

[0022] The sidewall 13 connects the outer periphery of the bottom plate 11 and the top plate 12 to each other over the entire periphery. In this embodiment, the heating element 100 is in contact with the outer periphery of the sidewall 13. In addition, a heat transfer member 14 is disposed inside the sidewall 13. The heat transfer member 14 overlaps the heating element 100 when viewed from the direction in which the heating element 100 and the heat receiving portion 10 are arranged.

[0023] The heat transfer member 14 is disposed so as to divide the storage chamber S10 into two parts, upper and lower, and is a thermally conductive member connected to the side wall 13. Here, the heat transfer member 14 is in the shape of a plate or block extending along a plane perpendicular to the Z axis, and has a first surface 14a facing the Z2 direction, a second surface 14b facing the Z1 direction, and a plurality of through holes 14c_1 to 14c_3 penetrating in a direction along the Z axis. Each of the through holes 14c_1 to 14c_3 is a space that opens on each of the first surface 14a and the second surface 14b. Therefore, in the storage chamber S10, a space located in the Z1 direction from the heat transfer member 14 communicates with a space located in the Z2 direction via the through holes 14c_1 to 14c_3. In the following, when the through holes 14c_1 to 14c_3 are not distinguished from each other, each of these may be simply referred to as a through hole 14c.

[0024] In this embodiment, the through holes 14c_1 to 14c_3 have the same shape. The widths of the through holes 14c_1 to 14c_3 are constant. In the example shown in Fig. 3, the cross section of each of the through holes 14c_1 to 14c_3 is circular. The through holes 14c_1 to 14c_3 having such a shape are formed by, for example, cutting.

[0025] The shapes of the through holes 14c_1 to 14c_3 may be different from each other. The widths of the through holes 14c_1 to 14c_3 may not be constant. The cross-sectional shape of each of the through holes 14c_1 to 14c_3 is not limited to a circle, and may be, for example, a polygon such as a rectangle, or an ellipse, as in Modification 3 described later. The number of through holes 14c provided in the heat transfer member 14 is not limited to three, and may be two or less, or four or more. The multiple through holes 14c provided in the heat transfer member 14 are not limited to being aligned in a direction along the X-axis, and may be regularly or irregularly arranged, for example, in a staggered or matrix pattern along a plane perpendicular to the Z-axis.

[0026] Here, the heat transfer member 14 is disposed below the liquid level RE0 of the refrigerant RE. Therefore, the first surface 14a, the second surface 14b, and the inner circumferential surfaces of the through holes 14c_1-14c_3 each constitute a part of the heat transfer surface FH in contact with the refrigerant RE. Note that the heat transfer surface FH includes the first surface 14a, the second surface 14b, and the inner circumferential surfaces of the through holes 14c_1-14c_3, as well as a part of the inner wall surface 13a of the side wall 13 and the inner wall surface 11a of the bottom plate 11.

[0027] Such a heat transfer member 14 has a function of promoting nucleate boiling of the refrigerant RE. More specifically, the heat transfer member 14 increases the area of ​​the heat transfer surface FH in contact with the refrigerant RE compared to a case in which the heat receiving part 10 is formed only of the bottom plate 11, the top plate 12, and the side wall 13. Therefore, it is possible to increase the amount of bubbles due to nucleate boiling of the refrigerant RE generated on the heat transfer surface FH.

[0028] Moreover, a structure for promoting nucleate boiling of the refrigerant RE is provided on the inner circumferential surface of each of the through holes 14c_1 to 14c_3. The structure is, for example, a structure for increasing the surface area of ​​the heat transfer surface FH. In the example shown in FIG. 2, a plurality of recesses or a plurality of protrusions are provided on the inner circumferential surface of each of the through holes 14c_1 to 14c_3 as a structure for promoting nucleate boiling of the refrigerant RE. The recesses or protrusions are, for example, grooves extending in the circumferential direction of the through holes 14c_1 to 14c_3. The grooves are, for example, processing marks obtained when the through holes 14c_1 to 14c_3 are formed by processing such as cutting, or thread grooves obtained by processing such as thread cutting after the formation of the through holes.

[0029] In addition, examples of the structure that promotes nucleate boiling of the refrigerant RE include, in addition to the multiple recesses or multiple protrusions as described above, multiple recesses formed by dimple processing, multiple uneven portions formed by blasting, a recess pattern or protrusion pattern formed by etching, the surface of a porous body having continuous pores, and parallel, lattice or wave-shaped fins formed by extrusion molding, welding or brazing, etc.

[0030] As described above, of the heat transfer surface FH with which the liquid refrigerant RE comes into contact at the heat receiving portion 10, the inner circumferential surfaces of the through holes 14c_1 to 14c_3 are the first portions FH1 that are likely to cause nucleate boiling of the refrigerant RE by heat from the heating element 100.

[0031] On the other hand, the portion of the heat transfer surface FH other than the first portion FH1 is a second portion FH2 in which nucleate boiling of the refrigerant RE is less likely to occur than in the first portion FH1. The second portion FH2 does not substantially cause nucleate boiling of the refrigerant RE, or even if nucleate boiling of the refrigerant RE occurs, the amount of bubbles generated by nucleate boiling per unit area is smaller than that of the first portion FH1.

[0032] Nucleate boiling of the refrigerant RE at each portion of the heat transfer surface FH is affected by the surface shape, such as the surface roughness, of each portion of the heat transfer surface FH. In general, for example, of two surfaces with different surface roughness in a surface that comes into contact with a liquid refrigerant, nucleate boiling is more likely to occur on the surface with the rougher surface and less likely to occur on the smoother surface.

[0033] Here, the surface roughness of the first portion FH1 is greater than that of the second portion FH2. The specific surface roughness of the first portion FH1 is not particularly limited, but from the viewpoint of favorably causing nucleate boiling of the refrigerant RE, it is preferable that it is within the range of, for example, 10 μm or more and 10,000 μm or less. On the other hand, the specific surface roughness of the second portion FH2 is not particularly limited, but from the viewpoint of favorably suppressing nucleate boiling of the refrigerant RE, it is preferable that the portion in the vicinity of the opening 41a described below is close to a mirror surface, and is preferably within the range of, for example, 1 μm or less. The surface roughness is the arithmetic mean roughness Ra.

[0034] The heat receiving part 10 is made of a material having excellent thermal conductivity. Specific examples of the material of the heat receiving part 10 include metal materials such as copper, aluminum, or an alloy of any of these. The materials constituting the bottom plate 11, top plate 12, side walls 13, and heat transfer member 14 of the heat receiving part 10 may be the same or different. The bottom plate 11, top plate 12, side walls 13, and heat transfer member 14 may each be made of a separate material, or the bottom plate 11, top plate 12, side walls 13, and heat transfer member 14 may be made of an integrated material.

[0035] The heat receiving portion 10 is thermally connected to the heat generating body 100. In this embodiment, the heat generating body 100 is thermally connected to the outer surface of the side wall 13. Here, "thermally connected" means that any one of the following conditions a, b, or c is satisfied. Condition a: The two members are in direct physical contact. Condition b: The two members are disposed with a gap of 50 μm or less between them. Condition c: The two members are disposed with a heat generating capacity of 10 W·m -1 ·K -1The two components are physically connected via another member having the above thermal conductivity. Note that a heat transfer grease, adhesive, etc. may be present between the two components under each condition. In this case, it is preferable that the adhesive contains a heat conductive filler, etc., from the viewpoint of increasing the thermal conductivity.

[0036] 1-2b. Heat dissipation part The heat dissipation section 20 is a structure having a condensation chamber S20, and dissipates heat from the heat receiving section 10. The condensation chamber S20 is a space in which the refrigerant RE is condensed from a vaporized state to a liquid state. In the heat dissipation section 20, the gas-phase refrigerant generated in the heat receiving section 10 is condensed to generate a liquid-phase refrigerant. Here, the heat dissipation section 20 condenses and liquefies the gas-phase refrigerant in the condensation chamber S20 by dissipating heat through heat exchange with an external fluid. The external fluid is not particularly limited as long as it is a fluid flowing outside the condensation chamber S20, and may be either a liquid or a gas, but is typically, for example, air.

[0037] In the example shown in FIG. 2, the heat dissipation unit 20 has a container 21 and a plurality of heat dissipation fins 22. The container 21 has a condensation chamber S20 as an internal space. The container 21 has a bottom plate 211, a top plate 212, and a side wall 213. The space surrounded by these is the condensation chamber S20. The bottom plate 211 and the top plate 212 are each a flat plate extending in a direction intersecting the Z axis. However, the bottom plate 211 is located in the Z2 direction relative to the top plate 212, and the bottom plate 211 has holes for connection to the first pipe section 30 and the second pipe section 40. The bottom plate 211 and the top plate 212 are arranged so as to be parallel to each other, and the side wall 213 is arranged between them. The side wall 213 connects the outer peripheries of the bottom plate 211 and the top plate 212 to each other over the entire circumference.

[0038] In this embodiment, the side wall 213 has a cylindrical shape, and the condensation chamber S20 has a columnar shape. The shape of the condensation chamber S20 is not limited to a columnar shape, and may be, for example, a prismatic shape. The shapes of the inner peripheral surface and the outer peripheral surface of the side wall 213 may be different from each other.

[0039] The container 21 is made of a material having excellent thermal conductivity. Specific examples of the material of the container 21 include metal materials such as copper, aluminum, and alloys of either of these.

[0040] Each heat dissipation fin 22 is thermally connected to the container 21. Each heat dissipation fin 22 is a flat plate-shaped member. The multiple heat dissipation fins 22 are arranged at intervals from each other in the thickness direction. Each heat dissipation fin 22 is made of a material with excellent thermal conductivity. Specific materials for the heat dissipation fins 22 include metal materials such as copper, aluminum, or an alloy of either of these. Each heat dissipation fin 22 is provided with a hole for inserting the container 21. The heat dissipation fin 22 is fixed to the container 21 by, for example, expanding, press-fitting, adhesive, screwing, brazing, welding, or the like.

[0041] The shape of the heat dissipation fins 22 is not limited to the example shown in Fig. 2 and may be any shape. The heat dissipation fins 22 may be provided as necessary, and may be omitted. However, by having the heat dissipation unit 20 have a plurality of heat dissipation fins 22, the gas phase refrigerant can be efficiently condensed and liquefied.

[0042] 1-2c. First pipe section The first pipe section 30 has a first flow path S30 that transports the gas-phase refrigerant generated by vaporizing the refrigerant RE in the heat receiving section 10 to the heat dissipating section 20. In this embodiment, the first pipe section 30 is composed of a steam pipe 31 that extends linearly along the Z axis. The steam pipe 31 is a pipe that has the first flow path S30 as an internal space.

[0043] The steam pipe 31 is made of a metal material such as copper, aluminum, or an alloy of any of these. The steam pipe 31 is fixed to the top plate 12 and the bottom plate 211 by brazing or the like. The material of the steam pipe 31 is not limited to a metal material, and may be, for example, a ceramic material or a resin material.

[0044] The first pipe section 30 is connected to each of the heat receiving section 10 and the heat dissipating section 20, and has an opening 31a that opens toward the heat receiving section 10 and an opening 31b that opens toward the heat dissipating section 20. The opening 31a is a space surrounded by the edge of the inner circumferential surface 31c of the first pipe section 30 in the Z2 direction. The opening 31b is a space surrounded by the edge of the inner circumferential surface 31c of the first pipe section 30 in the Z1 direction.

[0045] Here, the opening 31a is located on the same plane as the inner wall surface 12a, which is the surface of the top plate 12 facing the Z2 direction. Also, a part of the first pipe section 30 protrudes in the Z1 direction further than the bottom plate 211 of the heat dissipation section 20. Therefore, the opening 31b is located in the Z1 direction further than the bottom plate 211. Note that the first flow path S30 may be formed by the steam pipe 31 and the top plate 12 of the heat receiving section 10 described above. In this case, the opening 31a is formed by a hole provided in the top plate 12.

[0046] The first flow path S30 is a space surrounded by the inner circumferential surface 31c of the first pipe portion 30. The first flow path S30 communicates with the storage chamber S10 via an opening 31a, and communicates with the condensation chamber S20 via an opening 31b.

[0047] In the example shown in Fig. 2, the width of the first flow path S30 is constant. The cross-sectional area of ​​the first flow path S30 is constant. The cross-sectional shape of the first flow path S30 is circular. The cross-sectional shape of the first flow path S30 is not limited to a circle, and may be, for example, a polygon such as a rectangle, an ellipse, or the like. The first flow path S30 may have a bent or curved portion.

[0048] 1-2d.Second pipe section The second pipe section 40 has a second flow path S40 that transports the liquid-phase refrigerant generated by condensing the gas-phase refrigerant in the heat dissipation section 20 to the heat receiving section 10. In this embodiment, the second pipe section 40 is composed of a liquid pipe 41 that extends linearly along the Z axis. The liquid pipe 41 is a pipe that has the second flow path S40 as an internal space.

[0049] The liquid pipe 41 is made of a metal material such as copper, aluminum, or an alloy of any of these. The liquid pipe 41 is fixed to the top plate 12 and the bottom plate 211 by brazing or the like. The material of the liquid pipe 41 is not limited to a metal material, and may be, for example, a ceramic material or a resin material. The material of the liquid pipe 41 may be the same as or different from the material of the steam pipe 31.

[0050] The second pipe section 40 is connected to each of the heat receiving section 10 and the heat dissipating section 20, and has an opening 41a which is an example of a "first opening" that opens toward the heat receiving section 10, and an opening 41b which is an example of a "second opening" that opens toward the heat dissipating section 20. The opening 41a is a space surrounded by the edge of the inner circumferential surface 41c of the second pipe section 40 in the Z2 direction. The opening 41b is a space surrounded by the edge of the inner circumferential surface 41c of the second pipe section 40 in the Z1 direction.

[0051] Here, a part of the second pipe section 40 protrudes in the Z2 direction beyond the top plate 12 of the heat receiving section 10. In this embodiment, the second pipe section 40 is inserted into the through hole 14c of the heat transfer member 14 described above, and the opening 41a is located in the Z2 direction beyond the heat transfer member 14. Therefore, the opening 41a is located between the heat transfer member 14 and the bottom plate 11. Also, the opening 41b is located on the same plane as the surface of the bottom plate 211 of the heat dissipation section 20 facing the Z1 direction. The second flow path S40 may be formed by the liquid pipe 41 and the bottom plate 211 of the heat dissipation section 20 described above. In this case, the opening 41b is formed by a hole provided in the bottom plate 211.

[0052] The second flow path S40 is a space surrounded by the inner circumferential surface 41c of the second pipe portion 40. The second flow path S40 communicates with the storage chamber S10 via an opening 41a, and communicates with the condensation chamber S20 via an opening 41b.

[0053] The cross-sectional area of ​​the second flow path S40 is smaller than that of the first flow path S30. That is, the cross-sectional area of ​​the first flow path S30 is larger than that of the second flow path S40. Therefore, the gas-phase refrigerant can be transported more smoothly in the first flow path S30 than in a configuration in which the cross-sectional area of ​​the first flow path S30 is equal to or smaller than that of the second flow path S40. The cross-sectional area of ​​the second flow path S40 may be equal to that of the first flow path S30.

[0054] In the example shown in Fig. 2, the width of the second flow path S40 is constant. The cross-sectional area of ​​the second flow path S40 is constant. The cross-sectional shape of the second flow path S40 is circular. The cross-sectional shape of the second flow path S40 is not limited to a circle, and may be, for example, a polygon such as a rectangle, an ellipse, or the like. The second flow path S40 may have a bent or curved portion.

[0055] In the above-described second pipe section 40, the opening 41a is located between the heat transfer member 14 and the bottom plate 11, as described above. Here, as described above, the inner circumferential surface of the through hole 14c of the heat transfer member 14 is the first portion FH1 that causes nucleate boiling of the refrigerant RE, whereas the inner wall surface 11a of the bottom plate 11 is the second portion FH2 that causes less nucleate boiling of the refrigerant RE than the first portion FH1. The distance L2 between the opening 41a and the second portion FH2 is shorter than the distance L1 between the opening 41a and the first portion FH1. For this reason, bubbles B generated by nucleate boiling of the refrigerant RE in the first portion FH1 are less likely to enter the opening 41a.

[0056] The distance L1 is the shortest distance from the opening 41a through the liquid refrigerant RE to the first portion FH1. If it's long 2, since the end face of the liquid pipe 41 in the Z2 direction is parallel to the inner wall surface 11a of the bottom plate 11, the end face and the inner wall surface 11a are spaced apart from each other so as not to impede the outflow of the liquid-phase refrigerant from the opening 41a. The end face may be inclined with respect to the inner wall surface 11a or may have a notch or the like. In this case, the end face and the inner wall surface 11a may come into contact with each other. That is, in this case, the distance L 2 may be zero.

[0057] The distance L2 is the shortest distance from the opening 41a through the liquid refrigerant RE to the second portion FH2. 、 Distance L1 If it's short However, when the opening 41a is located below the first portion FH1 as in this embodiment, the distance can be appropriately determined depending on the shape and size required for the heat receiving portion 10, but is preferably 1 mm or more. In this case, the intrusion of air bubbles B from the first portion FH1 into the opening 41a can be suitably reduced.

[0058] 1-3. Summary As described above, the boil cooling device 1 includes the heat receiving section 10, the heat dissipating section 20, the first pipe section 30, and the second pipe section 40. The heat receiving section 10 accommodates the refrigerant RE and receives heat from the heating element 100. The heat dissipating section 20 dissipates heat from the heat receiving section 10. The first pipe section 30 transports the gas phase refrigerant generated by vaporizing the refrigerant RE in the heat receiving section 10 to the heat dissipating section 20. The second pipe section 40 transports the liquid phase refrigerant generated by condensing the gas phase refrigerant in the heat dissipating section 20 to the heat receiving section 10.

[0059] Here, the heat receiving portion 10 has a heat transfer surface FH that contacts the liquid refrigerant RE to be vaporized by heat from the heating element 100. The heat transfer surface FH has a first portion FH1 that causes nucleate boiling of the refrigerant RE, and a second portion FH2 that causes nucleate boiling of the refrigerant RE less easily than the first portion FH1. The second pipe portion 40 has an opening 41a that is an example of a "first opening" that opens toward the heat receiving portion 10, and an opening 41b that is an example of a "second opening" that opens toward the heat dissipation portion 20.

[0060] In addition, the opening 41a is positioned below a liquid level RE0 of the refrigerant RE contained in the heat receiving portion 10. The distance L2 between the opening 41a and the second portion FH2 is shorter than the distance L1 between the opening 41a and the first portion FH1.

[0061] In the above-described boil cooling device 1, since the opening 41a is located below the liquid level RE0 of the refrigerant RE in the heat receiving section 10, it is possible to prevent the gas-phase refrigerant generated in the heat receiving section 10 from flowing into the opening 41a. Therefore, it is possible to make it easier for the gas-phase refrigerant from the heat receiving section 10 to flow into the first pipe section 30.

[0062] Moreover, since the distance L2 between the opening 41a and the second portion FH2 is shorter than the distance L1 between the opening 41a and the first portion FH1, it is also possible to prevent the bubbles B generated by nucleate boiling of the refrigerant RE in the first portion FH1 from being mixed into the opening 41a. This makes it possible to reduce the obstruction of the inflow of the liquid phase refrigerant from the second pipe portion 40 to the heat receiving portion 10 by the bubbles B. As a result, the circulation of the refrigerant RE from the heat receiving portion 10 through the first pipe portion 30, the heat dissipation portion, and the second pipe portion 40 in this order to return to the heat receiving portion 10 is performed more smoothly than in the past, thereby reducing the deterioration of the cooling performance.

[0063] As described above, in the region overlapping with the opening 41a as viewed in the vertical direction, the first portion FH1 does not exist below the opening 41a. Bubbles B generated by nucleate boiling in the first portion FH1 move vertically upwards toward the liquid surface RE0 of the refrigerant RE in the heat receiving portion 10 due to their buoyancy. Therefore, from the viewpoint of reducing the intrusion of the bubbles B into the opening 41a, it is preferable that the first portion FH1 does not exist below the opening 41a in the region overlapping with the opening 41a as viewed in the vertical direction.

[0064] As described above, the opening 41a and the second portion FH2 are located below the first portion FH1. Therefore, the distance L2 can be made shorter than the distance L1. Even if the refrigerant RE flows in the heat receiving portion 10, it is possible to reduce the amount of bubbles B generated by nucleate boiling in the first portion FH1 entering the opening 41a.

[0065] Furthermore, as described above, the first portion FH1 extends along a vertical line. Therefore, the bubbles B generated by the nucleate boiling of the refrigerant RE in the first portion FH1 are easily separated from the heat transfer surface FH. As a result, the retention of the bubbles B on the heat transfer surface FH is reduced, so that the deterioration of the cooling performance can be reduced. In addition, when the heat receiving portion 10 and the heating element 100 are arranged side by side along the horizontal direction, the heat from the heating element 100 is easily transferred to the first portion FH1, so that the nucleate boiling of the refrigerant RE can be efficiently generated in the first portion FH1. Note that "extending along a vertical line" includes both extending in a direction that coincides with the vertical line and extending in a direction that is inclined at 45° or less with respect to the vertical line.

[0066] In this embodiment, as described above, the heat receiving portion 10 has a heat transfer member 14 having a through hole 14c extending along a vertical line. At least a part of the inner circumferential surface of the through hole 14c is the first portion FH1. In addition, the second pipe portion 40 is inserted into the through hole 14c. By using the heat transfer member 14 having the through hole 14c, there is an advantage that the area of ​​the heat transfer surface FH in the heat receiving portion 10 can be easily increased. In addition, by inserting the first pipe portion 30 into the through hole 14c of the first pipe portion 30, the opening 41a can be positioned below the first portion FH1.

[0067] As described above, the opening 41a is located below the through hole 14c. Therefore, even if the first portion FH1 is provided on the entire inner wall surface of the through hole 14c, the opening 41a can be located below the first portion FH1.

[0068] Furthermore, as described above, the opening 41a faces downward. Therefore, compared to a configuration in which the opening 41a faces vertically upward or horizontally, there is an advantage that the manufacturing or assembly of the second pipe section 40 can be completed easily. On the other hand, when the opening 41a faces downward, compared to a configuration in which the opening 41a faces vertically upward or horizontally, if bubbles B are generated near the opening 41a due to nucleate boiling, the bubbles B are more likely to enter the opening 41a. Therefore, in this case, making the distance L2 between the opening 41a and the second portion FH2 shorter than the distance L1 between the opening 41a and the first portion FH1 as described above is useful in reducing the entry of the bubbles B into the opening 41a.

[0069] As described above, the surface roughness of the first portion FH1 is greater than the surface roughness of the second portion FH2, so that nucleate boiling of the refrigerant RE can be efficiently caused in the first portion FH1.

[0070] 2. Second embodiment A second embodiment of the present invention will be described below. In the following example, for elements having the same actions and functions as those in the previous embodiment, the reference numerals used in the description of the previous embodiment will be used and detailed descriptions of each will be omitted as appropriate.

[0071] 4 is a cross-sectional view of a boil cooling device 1A according to the second embodiment. The boil cooling device 1A is similar to the boil cooling device 1 of the first embodiment described above, except that it has a heat receiving part 10A instead of the heat receiving part 10. The heat receiving part 10A is similar to the heat receiving part 10, except that a suppression part 15 is added.

[0072] The suppression unit 15 has a function of suppressing nucleate boiling of the refrigerant RE so as to reduce the intrusion of air bubbles B into the opening 41a. The suppression unit 15 is formed of, for example, a super water-repellent coating film or a mirror surface. The suppression unit 15 is provided in the second portion FH2. More specifically, the suppression unit 15 is disposed on the inner wall surface 11a of the bottom plate 11 so as to be located vertically below the opening 41a.

[0073] The second embodiment described above can also reduce the deterioration of cooling performance, as in the first embodiment described above. In this embodiment, as described above, the suppression portion 15 for suppressing nucleate boiling of the refrigerant RE is provided in the second portion FH2 in a region overlapping with the opening 41a when viewed in the vertical direction. This can reduce the presence rate of bubbles B below the opening 41a. As a result, the intrusion of bubbles B into the opening 41a is effectively prevented.

[0074] 3. Third embodiment The third embodiment of the present invention will be described below. In the following exemplary embodiment, for elements having the same actions and functions as those in the above-mentioned embodiment, the reference numerals used in the description of the above-mentioned embodiment will be used and detailed descriptions of each will be omitted as appropriate.

[0075] 5 is a cross-sectional view of a boil cooling device 1B according to the third embodiment. The boil cooling device 1B is similar to the boil cooling device 1 of the first embodiment described above, except that it has a heat receiving section 10B and a second pipe section 40B instead of the heat receiving section 10 and the second pipe section 40. The heat receiving section 10B is similar to the heat receiving section 10, except that a suppression section 16 is added. The second pipe section 40B is similar to the second pipe section 40, except that it has a liquid pipe 41B instead of the liquid pipe 41.

[0076] The suppression portion 16 is formed of, for example, a super water-repellent coating film or a mirror surface, similar to the suppression portion 15 of the second embodiment described above. The suppression portion 16 is provided on a part of the inner circumferential surface of the through hole 14c_2 of the heat transfer member 14 so as to extend in the Z1 direction from the first surface 14a of the heat transfer member 14. Therefore, of the inner circumferential surface of the through hole 14c_2, a portion where the suppression portion 16 is not provided is a first portion FH1, and a portion where the suppression portion 16 is provided is a second portion FH2.

[0077] The liquid pipe 41B is similar to the liquid pipe 41 of the first embodiment, except for the length of protrusion from the top plate 12. The opening 41a of the liquid pipe 41B is located inside the through hole 14c_2. More specifically, the opening 41a is disposed at a position overlapping with the suppression portion 16 when viewed in a direction perpendicular to the Z axis.

[0078] The third embodiment described above can also reduce the deterioration of cooling performance, as in the first embodiment described above. In this embodiment, as described above, a part of the inner circumferential surface of the through hole 14c_2 is the second portion FH2. And the opening 41a is located in the through hole 14c_2. By providing the second portion FH2 on the inner circumferential surface of the through hole 14c_2 in this way, even if the opening 41a is located in the through hole 14c_2, it is possible to reduce the intrusion of the bubbles B generated by nucleate boiling in the first portion FH1 into the opening 41a.

[0079] 4. Fourth embodiment The fourth embodiment of the present invention will be described below. In the following example, for elements having the same actions and functions as those in the above embodiment, the reference numerals used in the description of the above embodiment will be used and detailed descriptions of each will be omitted as appropriate.

[0080] 6 is a cross-sectional view of a boil cooling device 1C according to a fourth embodiment. The boil cooling device 1C is similar to the boil cooling device 1 of the first embodiment described above, except that it has a heat receiving part 10C instead of the heat receiving part 10. The heat receiving part 10C is similar to the heat receiving part 10, except that the heat transfer member 14 is omitted and a suppression part 15 and a promotion part 17 are added.

[0081] In this embodiment, the heating element 100 is thermally connected to the outer surface of the bottom plate 11. The promotion portion 17 has a structure for promoting nucleate boiling of the refrigerant RE, and is provided on the inner wall surface 11a of the bottom plate 11 so as to surround the periphery of the suppression portion 15.

[0082] In the example shown in Fig. 6, the promotion portion 17 has a plurality of fins 17a. The plurality of fins 17a are, for example, parallel, lattice or wave-shaped protrusions, and are formed by extrusion molding, welding or brazing. Note that the promotion portion 17 is not limited to the example shown in Fig. 6, and may be, for example, a plurality of recesses formed by dimple processing, a plurality of uneven portions formed by blasting, a recess or protrusion pattern formed by etching, the surface of a porous body having continuous pores, or the like.

[0083] In the above configuration, the suppression portion 15 overlaps with the heating element 100 when viewed in the Z-axis direction, but nucleate boiling of the refrigerant RE on the inner wall surface 11a is suppressed in the range where the suppression portion 15 is provided. On the other hand, nucleate boiling of the refrigerant RE on the inner wall surface 11a is promoted in the range where the promotion portion 17 is provided. For this reason, the portion of the inner wall surface 11a where the promotion portion 17 is provided is the first portion FH1, and the portion where the suppression portion 15 is provided is the second portion FH2. Here, the distance L2 between the opening 41a and the second portion FH2 is shorter than the distance L1 between the opening 41a and the first portion FH1.

[0084] The fourth embodiment described above can reduce the deterioration of the cooling performance, as in the first embodiment described above. In this embodiment, as described above, each of the first portion FH1 and the second portion FH2 is located below the opening 41a. The first portion FH1 does not overlap the opening 41a when viewed in the vertical direction. On the other hand, the second portion FH2 overlaps the opening 41a when viewed in the vertical direction. When the heating element 100 is disposed below the heat receiving portion 10C as in this embodiment, heat from the heating element 100 is easily transferred to the inner wall surface 11a of the bottom plate 11, so by providing the first portion FH1 on the inner wall surface 11a, nucleate boiling of the refrigerant RE can be efficiently generated in the first portion FH1. Here, the second portion FH2 overlaps the opening 41a when viewed in the vertical direction, but the first portion FH1 does not overlap, so that it is possible to reduce the intrusion of the air bubbles B into the opening 41a.

[0085] 5. Fifth embodiment Hereinafter, a fifth embodiment of the present invention will be described. In the following exemplary embodiment, for elements having the same actions and functions as those in the above-mentioned embodiment, the reference numerals used in the description of the above-mentioned embodiment will be used, and detailed description of each will be omitted as appropriate.

[0086] 7 is a cross-sectional view of a boil cooling device 1D according to the fifth embodiment. The boil cooling device 1D is similar to the boil cooling device 1 of the first embodiment described above, except that it has a heat receiving section 10D and a second pipe section 40D instead of the heat receiving section 10 and the second pipe section 40. The heat receiving section 10D is similar to the heat receiving section 10, except that the heat transfer member 14 is omitted and a promotion section 18 is added. However, the connection position between the heat receiving section 10D and the second pipe section 40D is different from the connection position between the heat receiving section 10 and the second pipe section 40. The second pipe section 40D is similar to the second pipe section 40D, except that it has a liquid pipe 41D instead of the liquid pipe 41.

[0087] In this embodiment, similarly to the above-described fifth embodiment, the heating element 100 is thermally connected to the outer surface of the bottom plate 11. The promotion portion 18 is a structure for promoting nucleate boiling of the refrigerant RE, and is provided on the inner wall surface 11a of the bottom plate 11 and the inner wall surface 13a of the side wall 13, respectively.

[0088] Here, the promotion portion 18 is provided over a range of the inner wall surface 11a that is a predetermined distance or more away from the inner wall surface 13a so as to overlap the heating element 100 when viewed in the Z-axis direction. The promotion portion 18 is also provided over a range of the inner wall surface 13a that is a predetermined distance or more away from the inner wall surface 11a.

[0089] In the example shown in Fig. 7, the accelerating portion 18 has a plurality of fins 18a provided on the inner wall surface 11a and a plurality of fins 18b provided on the inner wall surface 13a. Each of the plurality of fins 18a and the plurality of fins 18b is, for example, a parallel-type, lattice-type, or wave-type protrusion, and is formed by extrusion molding, welding, brazing, or the like. Note that the accelerating portion 18 is not limited to the example shown in Fig. 7, and may be, for example, a plurality of recesses formed by dimple processing, a plurality of uneven portions formed by blasting, a recess or protrusion pattern formed by etching, the surface of a porous body having continuous pores, or the like.

[0090] In the above configuration, the portion of the inner wall surface 11a and the inner wall surface 13a where the promotion portion 18 is provided is the first portion FH1, and the portion where the promotion portion 18 is not provided is the second portion FH2. Here, the portion of the inner wall surface 11a where the promotion portion 18 is not provided has a portion that does not overlap with the heating element 100 when viewed in the Z-axis direction, and nucleate boiling of the refrigerant RE is suppressed in this portion compared to the portion that overlaps with the heating element 100 when viewed in the Z-axis direction. Note that a structure like the suppression portion 15 or the suppression portion 16 of the above-mentioned embodiment may be provided in this portion.

[0091] The liquid pipe 41D is similar to the liquid pipe 41, except that the liquid pipe 41D is connected to the side wall 13 and the opening 41a faces the horizontal direction. The liquid pipe 41D has a bent or curved portion, and is connected to the side wall 13 at a position lower than the above-mentioned multiple fins 18b. The opening 41a is disposed at a position away from the inner wall surface 13a of the side wall 13. The opening 41a may be disposed on the same plane as the inner wall surface 13a.

[0092] Here, the distance L2a or the distance L2b between the opening 41a and the second portion FH2 is shorter than the distance L1a or the distance L1b between the opening 41a and the first portion FH1. The distance L1a is the distance between the opening 41a and the multiple fins 18a. The distance L1b is the distance between the opening 41a and the multiple fins 18b. The distance L2a is the distance between the opening 41a and the inner wall surface 11a. The distance L2b is the distance between the opening 41a and the inner wall surface 13a.

[0093] According to the fifth embodiment, the deterioration of the cooling performance can be reduced as in the first embodiment. In this embodiment, the opening 41a faces the horizontal direction. Therefore, compared to a configuration in which the opening 41a faces downward, it is possible to make it difficult for the air bubbles B to enter the opening 41a.

[0094] 6. Application Examples Fig. 8 is a perspective view showing an application example of the boil cooling device 1. Fig. 8 shows an example in which a plurality of heat generating bodies 100 are cooled by a plurality of boil cooling devices 1.

[0095] 8, a plurality of boil cooling devices 1 and a plurality of heating elements 100 are arranged alternately in the direction along the Y axis. Here, the plurality of boil cooling devices 1 and the plurality of heating elements 100 are fixed by a fixing device (not shown) so that the adjacent boil cooling devices 1 and heating elements 100 are in close contact with each other. With the above configuration, the plurality of boil cooling devices 1 can cool the plurality of heating elements 100.

[0096] The heat dissipation fins 22 of two adjacent boiling cooling devices 1 may be integrally formed. The number of boiling cooling devices 1 is determined according to the number of heat generating bodies 100 to be cooled, and is not limited to the example shown in Fig. 8, and may be 5 or less or 7 or more. The example shown in Fig. 8 uses a boiling cooling device 1, but instead of at least one of the multiple boiling cooling devices 1, any of the boiling cooling devices 1A, 1B, 1C, and 1D described above may be used, or the boiling cooling devices 1, 1A, 1B, 1C, and 1D may be appropriately combined.

[0097] 7. Variations The present invention is not limited to the above-described embodiments, and various modifications are possible. Furthermore, the embodiments and modifications may be combined as appropriate.

[0098] 7-1. Variation 1 In the first to third embodiments described above, the structure for promoting nucleate boiling is provided in all of the plurality of through holes 14c, but there may be through holes 14c that are not provided with such a structure.

[0099] 9 is a cross-sectional view of a boiling cooling device 1E according to the first modification. The boiling cooling device 1E is similar to the boiling cooling device 1 of the first embodiment described above, except that it has a heat receiving portion 10E and a second pipe portion 40E instead of the heat receiving portion 10 and the second pipe portion 40. The heat receiving portion 10E is similar to the heat receiving portion 10, except that the structure for promoting nucleate boiling is omitted for the through hole 14c_2. The second pipe portion 40E is similar to the second pipe portion 40, except that it has a liquid pipe 41E instead of the liquid pipe 41.

[0100] In the example shown in FIG. 9, among the through holes 14c_1 to 14c_3, the inner circumferential surfaces of the through holes 14c_1 and 14c_3 are the first portion FH1, and the inner circumferential surface of the through hole 14c_2 is the second portion FH2.

[0101] The liquid pipe 41E is similar to the liquid pipe 41 of the first embodiment, except for the length of protrusion from the top plate 12. The opening 41a of the liquid pipe 41E is located inside the through hole 14c_2. The above-described first modification can also reduce the deterioration of the cooling performance, as in the first embodiment described above.

[0102] 7-2.Modification 2 In the above-described first to fifth embodiments, one heat dissipation section 20, one first pipe section 30, and one second pipe section 40 are provided for each heat receiving section 10, but a plurality of heat dissipation sections 20, a plurality of first pipe sections 30, and a plurality of second pipe sections 40 may be provided for one heat receiving section 10. However, the heat dissipation fins 22 of a plurality of heat dissipation sections 20 may be integrally configured.

[0103] 10 is a cross-sectional view of a boil cooling device 1F according to Modification 2. The boil cooling device 1F is similar to the boil cooling device 1 of the first embodiment described above, except that it has a heat receiving section 10F and a heat dissipating section 20F instead of the heat receiving section 10 and the heat dissipating section 20, and the number of each of the first pipe sections 30 and the second pipe sections 40 is three.

[0104] The heat receiving section 10F is similar to the heat receiving section 10, except that it is connected to three first pipe sections 30 and three second pipe sections 40. The heat dissipating section 20F is similar to the heat dissipating section 20, except that the number of containers 21 is three. Here, each of the three second pipe sections 40 is individually inserted into the through hole 14c. With the above-described second modification, as with the first embodiment, it is possible to reduce the deterioration of cooling performance.

[0105] 7-3. Variation 3 FIG. 11 is a cross-sectional view of a boil cooling device 1G according to the third modification. FIG. 11 shows a cross section of the boil cooling device 1G corresponding to FIG. 3. The boil cooling device 1G is similar to the boil cooling device 1 of the first embodiment described above, except that it has a heat receiving part 10G instead of the heat receiving part 10. The heat receiving part 10G is similar to the heat receiving part 10, except that it has a heat transfer member 14G instead of the heat transfer member 14. The heat transfer member 14G is similar to the heat transfer member 14, except that it has through holes 14d_1 to 14d_3 instead of the through holes 14c_1 to 14c_3. Each of the through holes 14d_1 to 14d_3 has a rectangular cross section. The third modification described above can also reduce the deterioration of cooling performance, as in the first embodiment described above.

[0106] 7-4.Modification 4 FIG. 12 is a cross-sectional view of the boil cooling device 1H according to the fourth modification. In FIG. 12, a cross section of the boil cooling device 1H corresponding to FIG. 3 is shown. The boil cooling device 1H is similar to the boil cooling device 1 of the first embodiment described above, except that it has a heat receiving portion 10H instead of the heat receiving portion 10, and the numbers of the heat dissipation portions 20, the first pipe portion 30, and the second pipe portion 40 are different. The heat receiving portion 10H is similar to the heat receiving portion 10, except that it has a heat transfer member 14H instead of the heat transfer member 14. The heat transfer member 14H is similar to the heat transfer member 14, except that the number of the through holes 14c is different. In the example shown in FIG. 12, the number of the through holes 14c is nine, and the nine through holes 14c are arranged in a matrix. In addition, in the example shown in FIG. 12, the heat dissipation portion 20, the first pipe portion 30, and the second pipe portion 40 are provided for each through hole 14c. However, the heat dissipation fins 22 of the multiple heat dissipation portions 20 may be integrally formed. The fourth modification can also reduce the deterioration of cooling performance, similarly to the first embodiment described above. [Explanation of symbols]

[0107] 1... Boiling cooling device, 1A... Boiling cooling device, 1B... Boiling cooling device, 1C... Boiling cooling device, 1D... Boiling cooling device, 1E... Boiling cooling device, 1F... Boiling cooling device, 1G... Boiling cooling device, 1H... Boiling cooling device, 10... Heated part, 10A... Heated part, 10B... Heated part, 10C... Heated part, 10D... Heated part, 10E... Heated part, 10F... Heated part, 10G... Heated part, 10H... Heated part, 11... Bottom plate, 11a... Inner wall surface, 12... Top plate, 12a... Inner wall surface, 13... Side wall, 13a... Inner wall surface, 14... Heat transfer member, 14G... Heat transfer member, 14H... Heat transfer member, 14a... First surface, 14b... Second surface, 14c... Through hole, 14c_1... Through hole, 14c_2... Through hole, 14c_3... Through hole, 14d_1... Through hole, 15... Inhibiting part, 16... Inhibiting part, 17... Promoting part, 17a... Fin, 18... Promoting part, 18a... Fin, 18b... Fin, 20... Heat radiating part, 20F... Heat radiating part, 21... Container, 22... Heat radiating fin, 30... First pipe part, 31... Steam pipe, 31a... Opening, 31b... Opening, 31c... Inner peripheral surface, 40... Second pipe part, 40B... Second pipe part, 40D... Second pipe part, 40E... Second pipe part, 41... Liquid pipe, 41B... Liquid pipe, 41D... Liquid pipe, 41E... Liquid pipe, 41a... Opening (first opening), 41b... Opening (second opening), 41c... Inner peripheral surface, 100... Heating element, 211... Bottom plate, 212... Top plate, 213... Side wall, B... Bubble, FH... Heat transfer surface, FH1... First part, FH2... Second part, L1... Distance, L1a... Distance, L1b... Distance, L2... Distance, L2a... Distance, L2b... Distance, RE... Refrigerant, RE0... Liquid level, S10... Accommodation chamber, S20... Condensation chamber, S30... First flow path, S40... Second flow path.

Claims

1. a heat receiving portion that accommodates a refrigerant and receives heat from a heating element; A heat dissipation section that dissipates heat from the heat receiving section; A first pipe portion that transports a gas phase refrigerant generated by vaporizing the refrigerant in the heat receiving portion to the heat dissipating portion; a second pipe portion that transports a liquid-phase refrigerant generated by condensing the gas-phase refrigerant in the heat dissipation portion to the heat receiving portion, The heat receiving portion has a heat transfer surface that contacts a liquid refrigerant to be vaporized by heat from a heating element, The heat transfer surface has a first portion that causes nucleate boiling of the refrigerant and a second portion that causes nucleate boiling of the refrigerant less easily than the first portion, The heat receiving portion has a heat transfer member having a through hole extending along a vertical line, At least a part of an inner circumferential surface of the through hole is the first portion, The second pipe portion is inserted into the through hole, The first portion is composed of a plurality of concave portions or a plurality of convex portions aligned along a vertical line, The second pipe portion has a first opening that opens toward the heat receiving portion and a second opening that opens toward the heat dissipating portion, The first opening is located below a liquid level of the refrigerant contained in the heat receiving portion, the first opening and the second portion are each located below a lower end of the first portion, a shortest distance from the first opening through the liquid refrigerant to the first portion is longer than a shortest distance from the first opening through the liquid refrigerant to the second portion; Boiling cooler.

2. In a region overlapping with the first opening as viewed in the vertical direction, the first portion is not present below the first opening. The boiling cooling device according to claim 1.

3. The first opening is located below the through hole. The boiling cooling device according to claim 1 or 2.

4. The second portion is provided with a suppression portion that suppresses nucleate boiling of the refrigerant in a region that overlaps with the first opening when viewed in a vertical direction. The boiling cooling device according to claim 3.

5. A part of an inner circumferential surface of the through hole is the second portion, The first opening is located within the through hole. The boiling cooling device according to claim 1 or 2.

6. The first opening faces downward. The boil cooling device according to any one of claims 1 to 5.

7. A heat receiving section that accommodates a refrigerant and receives heat from a heating element; A heat dissipation section that dissipates heat from the heat receiving section; A first pipe portion that transports a gas phase refrigerant generated by vaporizing the refrigerant in the heat receiving portion to the heat dissipating portion; a second pipe portion that transports a liquid-phase refrigerant generated by condensing the gas-phase refrigerant in the heat dissipation portion to the heat receiving portion, The heat receiving portion has a heat transfer surface that contacts a liquid refrigerant to be vaporized by heat from a heating element, The heat transfer surface has a first portion that causes nucleate boiling of the refrigerant and a second portion that causes nucleate boiling of the refrigerant less easily than the first portion, The second pipe portion has a first opening that opens toward the heat receiving portion and a second opening that opens toward the heat dissipating portion, The first opening is located below a liquid level of the refrigerant contained in the heat receiving portion, an upper end of each of the first portion and the second portion is located below the first opening; The first portion does not overlap the first opening when viewed in a vertical direction, The second portion overlaps the first opening in a vertical direction, a shortest distance from the first opening through the liquid refrigerant to the first portion is longer than a shortest distance from the first opening through the liquid refrigerant to the second portion; Boiling cooler.

8. The first opening faces horizontally. The boiling cooling device according to claim 7.

9. The surface roughness of the first portion is greater than the surface roughness of the second portion. The boil cooling device according to any one of claims 1 to 8.

10. a heat receiving portion that accommodates a refrigerant and receives heat from a heating element; A heat dissipation section that dissipates heat from the heat receiving section; A first pipe portion that transports a gas phase refrigerant generated by vaporizing the refrigerant in the heat receiving portion to the heat dissipating portion; a second pipe portion that transports a liquid-phase refrigerant generated by condensing the gas-phase refrigerant in the heat dissipation portion to the heat receiving portion, The heat receiving portion has a heat transfer surface that contacts a liquid refrigerant to be vaporized by heat from a heating element, The heat transfer surface has a first portion that causes nucleate boiling of the refrigerant and a second portion that causes nucleate boiling of the refrigerant less easily than the first portion, The heat receiving portion has a heat transfer member having a through hole extending along a vertical line, At least a part of an inner circumferential surface of the through hole is the first portion, The second pipe portion is inserted into the through hole, The first portion is composed of a plurality of concave portions or a plurality of convex portions aligned along a vertical line, The second pipe portion has a first opening that opens toward the heat receiving portion and a second opening that opens toward the heat dissipating portion, The first opening is located below a liquid level of the refrigerant contained in the heat receiving portion, The first opening and the second portion are each located below a lower end of the first portion. Boiling cooling device.

Images