Method for manufacturing a boiling condenser and boiling condenser

Abstract

To provide a boiling type cooler capable of obtaining a boiling surface part having high boiling heat transfer performance with a simple step.SOLUTION: A method for manufacturing a boiling type cooler 100 is a method of manufacturing the boiling type cooler 100 comprising a boiling unit 10 that boils a refrigerant through heat exchange with a heating element HS, and a condensation unit 20 that condenses the refrigerant boiled by the boiling unit 10 and returns it to the boiling unit 10, and comprises a step of forming the condensation unit 20, and a step of forming the boiling unit 10. The step of forming the boiling unit 10 includes a step of forming at least a part of a boiling surface part 13 provided on a surface 11b of the heating element HS opposite to a mounting surface 11a and in contact with the refrigerant by additive manufacturing.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a boiling cooler and a boiling cooler, and more particularly to a method for manufacturing a boiling cooler and a boiling cooler including a boiling section for boiling a refrigerant and a condensing section for condensing the refrigerant and returning it to the boiling section.

Background Art

[0002] Conventionally, a boiling cooler including a boiling section for boiling a refrigerant and a condensing section for condensing the refrigerant and returning it to the boiling section has been known (see, for example, Patent Document 1).

[0003] In Patent Document 1, a thermosiphon cooler (boiling cooler) including a boiling section for boiling a refrigerant and a condensing section for condensing the refrigerant and returning it to the boiling section is disclosed. The boiling section includes an attachment surface to which a cooling object is attached and a boiling surface disposed on the back side of the attachment surface. A plurality of fins are formed on the boiling surface. The plurality of fins are formed by processing a plate-like member into corrugated fins, cutting out the processed corrugated fins and joining them to the boiling surface, and removing the tops of the joined corrugated fins by milling.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the thermosiphon cooler described in Patent Document 1, since a plurality of fins are formed on the boiling surface, it is possible to obtain a boiling surface with high boiling heat transfer performance. However, since many separate steps are required when forming the plurality of fins, the process becomes complicated. Therefore, it is desired to obtain a boiling section with high boiling heat transfer performance in a simple process.

[0006] This invention was made to solve the above-mentioned problems, and one of its objectives is to provide a method for manufacturing a boiling type cooler and a boiling type cooler that can obtain a boiling surface with high boiling heat transfer performance in a simple process. [Means for solving the problem]

[0007] To achieve the above objective, the method for manufacturing a boiling type cooler according to the first invention is a method for manufacturing a boiling type cooler comprising a boiling section that vaporizes a refrigerant by heat exchange with a heating element, and a condensing section that condenses the vaporized refrigerant and returns the condensed refrigerant to the boiling section, comprising the steps of forming the condensing section and forming the boiling section including a mounting section to which the condensing section is attached, wherein the step of forming the boiling section includes the step of forming a boiling surface that comes into contact with the refrigerant on the surface of the mounting section, which is opposite to the mounting surface to which the heating element is attached, and the step of forming the boiling surface includes the step of forming a plurality of protrusions that gradually increase in thickness from the base end to the tip. The process of forming multiple protrusions includes forming multiple linear protrusions extending in a first direction in a plane substantially parallel to the boiling surface, arranged in a second direction substantially perpendicular to the first direction in a plane substantially parallel to the boiling surface, and forming multiple protrusions arranged on the linear protrusions and between the linear protrusions in the second direction. nothing. Furthermore, by configuring it as described above, a boiling surface can be obtained that combines a projection having a shape that gradually widens from the base to the tip with linear projections. As a result, it is possible to increase the heat transfer area with the linear projections while improving the boiling heat transfer performance of the boiling surface by filling the space between the projections with refrigerant.

[0009] In the first invention described above, preferably, the boiling surface Shape the part The process includes forming at least a portion of the boiling surface by additive manufacturing using metal powder. With this configuration, a boiling surface with minute irregularities on its surface can be obtained by additive manufacturing using metal powder. As a result, boiling can be promoted by the minute irregularities on the surface, thus obtaining a boiling surface with higher boiling heat transfer performance.

[0010] In this case, preferably, the boiling surface Shape the part The process includes forming at least a portion of the boiling surface by powder bed fusion bonding as additive manufacturing. With this configuration, a boiling surface with minute irregularities on its surface can be easily obtained by powder bed fusion bonding, thus easily obtaining a boiling surface with higher boiling heat transfer performance.

[0012] In the above-mentioned first invention Preferably, The process of forming multiple protrusions is as follows:In a plane substantially parallel to the boiling surface, in a first and second direction which are substantially orthogonal to each other, the projection of Arranged in a matrix pattern Shape This process includes the creation of the boiling surface. With this configuration, a boiling surface with well-balanced protrusions can be obtained. As a result, since the protrusions are not unevenly distributed, the effect of improving the boiling heat transfer performance of the boiling surface by filling the spaces between the protrusions with refrigerant can be exerted evenly at any position on the boiling surface.

[0014] In the above-mentioned first invention Preferably, The process of forming multiple protrusions is as follows: Protrusions with a pitch smaller than the width of the protrusions of Multiple items lined up Shape This process includes the creation of the boiling surface. If the pitch of the protrusions becomes too large, the number of protrusions that can be placed on the boiling surface decreases, resulting in a lower boiling heat transfer performance on the boiling surface. Therefore, by configuring it as described above, it is possible to suppress the pitch of the protrusions from becoming too large, and thus prevent the number of protrusions that can be placed on the boiling surface from decreasing too much. As a result, the boiling heat transfer performance on the boiling surface can be appropriately set.

[0016] In the first invention described above, preferably, the boiling surface Shape the part The process includes forming the boiling surface without blasting after additive manufacturing. This configuration avoids the removal of minute surface irregularities in the boiling surface by blasting, thus enabling the creation of a boiling surface with high boiling heat transfer performance. Furthermore, it simplifies the manufacturing process of the boiling cooler compared to the case where blasting is performed. In the first invention described above, preferably, the step of forming a plurality of protrusions includes the step of forming a plurality of truncated pyramidal protrusions in a row. . In the first invention described above, preferably, the distance between the tips of adjacent protrusions is smaller than the width of the tip of one protrusion, and the distance between the base ends of adjacent protrusions is larger than the width of the tip of one protrusion. . In the first invention described above, preferably, the step of forming a plurality of protrusions includes the step of forming a plurality of protrusions in a staggered pattern. In the first invention described above, preferably, the step of forming the boiling surface includes a step of forming the boiling surface by performing a blast treatment after additive manufacturing. In the first invention described above, preferably, the step of forming the boiling portion includes the step of joining the attachment portion to the condensing portion by welding, brazing, or screw fastening.

[0019] The boiling cooler according to the second invention includes a boiling section that vaporizes a refrigerant by heat exchange with a heating element, and a condensing section that condenses the vaporized refrigerant and returns the condensed refrigerant to the boiling section. The boiling section includes an attachment section to which the condensing section is attached. The attachment section has an attachment surface to which the heating element is attached, and a boiling surface portion that is formed on the surface opposite to the attachment surface and contacts the refrigerant. A plurality of protrusions that gradually increase in thickness from the base end to the tip end are formed on the boiling surface portion. Furthermore, multiple linear protrusions are formed on the boiling surface, extending in a first direction within a plane substantially parallel to the boiling surface, and arranged in a second direction substantially perpendicular to the first direction within a plane substantially parallel to the boiling surface, and multiple protrusions are formed on the linear protrusions and between the linear protrusions in the second direction. exist.

[0020] In the boiling cooler according to the second invention, as described above, a plurality of protrusions that gradually increase in thickness from the base end to the tip end are formed on the boiling surface portion. As a result, a boiling surface portion that can fill the refrigerant between the protrusions can be obtained. As a result, when the refrigerant boils between the protrusions and around them, the refrigerant filled between the protrusions can be quickly supplied, so that it is possible to suppress the drying of the protrusions and their surroundings where the refrigerant has boiled. Thereby, it is possible to avoid a situation where boiling cannot occur due to the drying of the protrusions and their surroundings, so that the boiling heat transfer performance of the boiling surface portion can be enhanced. Furthermore, by configuring it as described above, a boiling surface can be obtained that combines a projection having a shape that gradually widens from the base to the tip with linear projections. As a result, it is possible to increase the heat transfer area with the linear projections while improving the boiling heat transfer performance of the boiling surface by filling the space between the projections with refrigerant.

[0021] In the above 2 invention, preferably, the boiling surface portion to , in a first direction and a second direction that are substantially orthogonal to each other in a plane substantially parallel to the boiling surface portion, a plurality of protrusions but are arranged in a matrix It is formed to be . With this configuration, a boiling surface portion with the protrusions arranged in a balanced manner can be obtained. As a result, since the protrusions are not arranged unevenly, the effect of enhancing the boiling heat transfer performance of the boiling surface portion by filling the refrigerant between the protrusions can be evenly exerted at any position on the boiling surface portion.

[0023] In the above 2 invention, preferably, the boiling surface portion to , a plurality of protrusions are arranged at a pitch smaller than the width of the protrusions but side by side It is formed to beWith this configuration, if the pitch of the protrusions becomes too large, the number of protrusions that can be placed on the boiling surface decreases, resulting in a lower boiling heat transfer performance on the boiling surface. Therefore, by configuring it as described above, it is possible to suppress the protrusion pitch from becoming too large, and thus prevent the number of protrusions that can be placed on the boiling surface from decreasing too much. As a result, the boiling heat transfer performance on the boiling surface can be appropriately set. In the second invention described above, the projection is preferably truncated pyramidal in shape. In the second invention described above, preferably, the distance between the tips of adjacent protrusions is smaller than the width of the tip of one protrusion, and the distance between the base ends of adjacent protrusions is larger than the width of the tip of one protrusion. In the second invention described above, preferably, a plurality of protrusions are formed in a staggered pattern on the boiling surface. In the second invention described above, preferably, the mounting portion is joined to the condensed portion by welding, brazing, or screw fastening. [Effects of the Invention]

[0024] According to the present invention, as described above, a boiling surface with high boiling heat transfer performance can be obtained through a simple process. [Brief explanation of the drawing]

[0025] [Figure 1] This is a schematic perspective view showing a boiling type condenser according to the first embodiment. [Figure 2] This is a schematic exploded perspective view (1) showing a boiling type condenser according to the first embodiment. [Figure 3] This is a schematic exploded perspective view (2) showing a boiling type condenser according to the first embodiment. [Figure 4] This is a schematic perspective view showing the first example of the boiling surface. [Figure 5] Figure 4 is a schematic partial cross-sectional view of the boiling surface. [Figure 6] This is a schematic perspective view showing a second example of the boiling surface. [Figure 7] Figure 6 is a schematic partial cross-sectional view of the boiling surface. [Figure 8] This is a schematic perspective view showing a third example of the boiling surface. [Figure 9] Figure 8 is a schematic partial cross-sectional view of the boiling surface. [Figure 10] This is a schematic perspective view showing the fourth example of the boiling surface. [Figure 11] Figure 10 is a schematic partial cross-sectional view of the boiling surface. [Figure 12] This is a schematic perspective view showing the fifth example of the boiling surface. [Figure 13] Figure 12 is a schematic partial cross-sectional view of the boiling surface. [Figure 14] This diagram illustrates the attachment of the mounting portion of the boiling type cooler to the condensing section according to the first embodiment. [Figure 15] This diagram illustrates the attachment of the heating element to the mounting section of the boiling type cooler according to the first embodiment. [Figure 16] This diagram illustrates the state in which a heating element is attached to the boiling type cooler according to the first embodiment. [Figure 17] This is a schematic exploded perspective view showing a boiling type condenser according to a first modification of the first embodiment. [Figure 18] This is a schematic exploded perspective view showing a boiling type condenser according to a second modification of the first embodiment. [Figure 19] This is a schematic perspective view showing a boiling type condenser according to the second embodiment. [Figure 20] This is a schematic exploded perspective view (1) showing the boiling section of a boiling type cooler according to the second embodiment. [Figure 21] This is a schematic exploded perspective view (2) showing the boiling section of a boiling type cooler according to the second embodiment. [Figure 22] This diagram illustrates the attachment of the mounting portion of the boiling type cooler to the evaporator body according to the second embodiment. [Figure 23] This diagram illustrates the attachment of the evaporation section of a boiling type cooler to the condensing section according to the second embodiment. [Figure 24] This diagram illustrates the state in which a heating element is attached to a boiling type cooler according to the second embodiment. [Figure 25] This is a schematic exploded perspective view showing the evaporation section of a boiling condenser according to the first modification of the second embodiment. [Figure 26] This is a schematic exploded perspective view showing the evaporation section of a boiling condenser according to a second modification of the second embodiment. [Figure 27] This graph shows the boiling heat transfer performance measurement results at the boiling surface of Example 1 and the Comparative Example. [Figure 28] This graph shows the boiling heat transfer performance measurement results at the boiling surface for Example 2 and the Comparative Example. [Figure 29] This graph shows the boiling heat transfer performance measurement results at the boiling surface for Example 3 and the Comparative Example. [Figure 30] This graph shows the boiling heat transfer performance measurement results at the boiling surface for Example 4 and the Comparative Example. [Figure 31] This graph shows the measurement results of the boiling heat transfer performance at the boiling surface in Examples 1 to 4. [Modes for carrying out the invention]

[0026] Embodiments of the present invention will be described below with reference to the drawings.

[0027] [First Embodiment] Referring to Figures 1 to 13, the configuration of the boiling type cooler 100 (hereinafter referred to as "cooler 100") according to the first embodiment will be described. Cooler 100 is a boiling cooling type cooler that utilizes the phase change (latent heat) of vaporization and condensation of the refrigerant to absorb heat from the heat-generating element HS and dissipate it to the outside. The heat-generating element HS is, for example, a CPU (central processing unit). The heat-generating element HS is not particularly limited. The refrigerant is, for example, a fluorocarbon, a hydrocarbon, or water. The refrigerant is not particularly limited.

[0028] In the following, two directions that are approximately orthogonal to each other in the horizontal plane will be referred to as the X and Y directions, respectively. The vertical direction that is approximately orthogonal to the horizontal plane (XY plane) will be referred to as the Z direction. Note that the Z direction is parallel to the direction of gravity, and gravity is assumed to act in a downward direction.

[0029] As shown in Figures 1 to 3, the cooler 100 comprises a boiling section 10 and a condensing section 20. The boiling section 10 boils the refrigerant through heat exchange with the heating element HS. The condensing section 20 condenses the refrigerant boiled by the boiling section 10 and returns it to the boiling section 10. In the first embodiment, the boiling section 10 and the condensing section 20 are integrated.

[0030] The boiling section 10 includes a mounting section 11 and a housing section 12 (see Figure 3). The mounting section 11 is a plate-shaped section extending horizontally. The lower surface (Z2 direction side) of the mounting section 11 is the mounting surface 11a of the heating element HS. On the mounting section 11, a boiling surface section 13 is provided on the upper surface 11b (Z1 direction side) opposite to the mounting surface 11a. The housing section 12 houses the liquid refrigerant. The housing section 12 is partitioned by a hole 20a formed in the condensing section 20 and the surface 11b of the mounting section 11. The housing section 12 is provided as a recess that is recessed downward (Z2 direction). Within the housing section 12, the boiling surface section 13 is in contact with the liquid refrigerant. Details of the boiling surface section 13 will be described later.

[0031] The condensing section 20 is composed of a plate fin type heat exchanger. The condensing section 20 includes a refrigerant passage 21 and an external passage 22. The refrigerant passage 21 and the external passage 22 are arranged alternately with a partition plate in between. The refrigerant passage 21 is a flow path for the refrigerant. The refrigerant passage 21 is in communication with the housing section 12 of the boiling section 10. Specifically, the first stage (closest to the Z2 direction) refrigerant passage 21 is in communication with the housing section 12 of the boiling section 10, and the second stage and above refrigerant passages 21 are also in internal communication. Refrigerant flows through all of the refrigerant passages 21. Corrugated fins 21a (see Figure 3) extending in the X direction are arranged inside the refrigerant passage 21. The external passage 22 is a flow path for the external fluid. The external fluid is a fluid that cools the refrigerant, for example, air. The external fluid is not particularly limited. The external passage 22 is open to the outside. Corrugated fins 22a extending in the Y direction are arranged within the external passage 22.

[0032] When heat from the heating element HS is transferred to the boiling surface section 13 via the mounting section 11, the liquid refrigerant in the containment section 12 is heated and boils. The refrigerant vaporized by boiling moves into the refrigerant passage 21 communicating with the containment section 12, and is cooled and condensed by the external fluid flowing through the external passage 22. The refrigerant liquefied by condensation moves through the refrigerant passage 21 and returns to the containment section 12. In this way, the refrigerant sealed in the cooler 100 circulates between the boiling section 10 and the condensing section 20. This cools the heating element HS.

[0033] (Composition of the boiling surface) In this first embodiment, at least a portion of the boiling surface 13 is formed by additive manufacturing. Specifically, at least a portion of the boiling surface 13 is formed by additive manufacturing using metal powder. More specifically, at least a portion of the boiling surface 13 is formed by powder bed fusion (PBF) as an additive manufacturing method. Powder bed fusion is an additive manufacturing method that forms a three-dimensional additive body (such as the boiling surface 13) by repeatedly performing the steps of forming a layer of metal powder and irradiating the formed portion of the metal powder layer with a high-energy beam (such as laser light or an electron beam) to sinter (melt and harden) the metal powder in the formed portion. The surface of the boiling surface 13 formed by additive manufacturing has minute irregularities originating from the sintering of the metal powder by the high-energy beam. The material of the metal powder used in the additive manufacturing, i.e., the material of the boiling surface 13, is not particularly limited, but for example, it is aluminum (including aluminum alloys). In the case of aluminum, for example, a silicon-based aluminum alloy called Al-Si10-Mg can be used.

[0034] Referring to Figures 4 to 13, an example of the configuration of the boiling surface portion 13 will be described. In the following, two directions that are substantially orthogonal to each other in a plane substantially parallel to the boiling surface portion 13 will be referred to as directions A and B, respectively. The direction substantially orthogonal to the plane substantially parallel to the boiling surface portion 13 will be referred to as direction C. In the first embodiment, direction C coincides with direction Z, direction C1 coincides with direction Z1, and direction C2 coincides with direction Z2. The portion of the boiling surface portion 13 on the C2 direction side is joined to the surface 11b of the mounting portion 11. Directions A and B are examples of the "first direction" and "second direction" in the claims, respectively.

[0035] (First example of the boiling surface) Figures 4 and 5 show the first example. In the first example, the boiling surface 13 is composed of multiple linear protrusions 13a extending in direction A, arranged in direction B. The multiple linear protrusions 13a are provided on the bottom plate 13b and protrude from the bottom plate 13b toward direction C1. In addition, by arranging multiple linear protrusions 13a extending in direction A in direction B, multiple grooves extending in direction A and recessed toward direction C2 are arranged in direction B between each linear protrusion 13a in direction B. The linear protrusions 13a are rectangular parallelepipeds.

[0036] Each linear projection 13a has a width W1 and a height H1. The width W1 is the length of the linear projection 13a in direction B. The height H1 is the length of the linear projection 13a in direction C. The linear projections 13a are arranged in line in direction B with a pitch P1. The pitch P1 is the distance between adjacent linear projections 13a in direction B. The pitch P1 is also the width of the groove in direction B. In the examples shown in Figures 4 and 5, the width W1, height H1, and pitch P1 are the same length, but are not particularly limited. For example, the width W1, height H1, and pitch P1 are approximately 2 mm each.

[0037] (Second example of the boiling surface) Figures 6 and 7 show a second example. In the second example, the boiling surface portion 13 is composed of multiple projections 13c arranged in a matrix, each having a shape that gradually widens from the base (C2 direction side) to the tip (C1 direction side). Specifically, the boiling surface portion 13 is composed of multiple projections 13c arranged in a matrix in directions A and B. The multiple projections 13c are provided on the bottom plate 13b and protrude from the bottom plate 13b toward the C1 direction side. Furthermore, by arranging multiple projections 13c in a matrix in directions A and B, spaces are formed between the projections 13c that can be filled with refrigerant. The projections 13c are frustoconical in shape, gradually widening from the C2 direction side to the C1 direction side. The projections 13c have an upper base on the C2 direction side, a lower base on the C1 direction side, and four tapered surfaces connecting the upper and lower bases.

[0038] Each projection 13c has a width W2 and a height H2. The width W2 is the length of the lower base of the projection 13c in directions A and B. The height H2 is the length of the projection 13c in direction C. Each tapered surface (side) of the projection 13c is inclined at an angle θ2 with respect to the AB plane. The projections 13c are arranged in a line in directions A and B with a pitch P2. The pitch P2 is the distance between adjacent projections 13c in directions A and B. In the examples shown in Figures 6 and 7, the width W2 and height H2 are the same length, but are not particularly limited. Also, in the examples shown in Figures 6 and 7, the pitch P2 is smaller than the width W2. The boiling surface 13 shown in Figures 6 and 7 is composed of multiple projections 13c arranged at a pitch P2 smaller than the width W2 of the projections 13c. However, the pitch P2 is not particularly limited. For example, the width W2 and height H2 are approximately 0.5 mm, the pitch P2 is approximately 0.4 mm, and the tilt angle θ2 is approximately 70 degrees.

[0039] (Third example of the boiling surface) Figures 8 and 9 show a third example. In the third example, the boiling surface 13 is constructed by arranging multiple linear projections 13d extending in the A direction in the B direction, and arranging multiple projections 13c on the linear projections 13d and between the linear projections 13d in the B direction (i.e., in grooves). The multiple linear projections 13d are provided on the bottom plate 13b and protrude from the bottom plate 13b toward the C1 direction. Furthermore, by arranging multiple linear projections 13d extending in the A direction in the B direction, multiple grooves extending in the A direction and recessing toward the C2 direction are arranged in the B direction between each linear projection 13d in the B direction. The linear projections 13d are prismatic in shape with a tapered surface 13da on the C2 direction side. The tapered surface 13da is provided corresponding to the projections 13c arranged in the grooves. Specifically, the tapered surface 13da is positioned in the groove and is located opposite the projection 13c closest to the tapered surface 13da in the B direction, and is inclined toward the opposite side of the tapered surface of the projection 13c. The projections 13c are arranged in a matrix in the A and B directions on both the linear projection 13d and the groove (on the bottom plate 13b).

[0040] Each linear projection 13d has a width W3 and a height H3. The width W3 is the length of the linear projection 13d in the B direction. The height H3 is the length of the linear projection 13d in the C direction. The linear projections 13d are arranged in a line in the B direction with a pitch P3. The pitch P3 is the distance between adjacent linear projections 13d in the B direction. The pitch P3 is also the width of the groove in the B direction. In the examples shown in Figures 8 and 9, the height H3 is smaller than the width W3 and the pitch P3 is larger than the height H3, but this is not particularly limited. Also, each tapered surface 13da of the linear projection 13d is inclined by an inclination angle θ3 with respect to the AB plane. The inclination angle θ3 is the same value as the inclination angle θ2. For example, the width W3 is approximately 2.0 mm, the height H3 is approximately 1.5 mm, the pitch P3 is approximately 2.0 mm, and the inclination angle θ3 is approximately 70 degrees.

[0041] (Fourth example of the boiling surface) Figures 10 and 11 show a fourth example. In the fourth example, the boiling surface 13 is composed of multiple depressions 13e arranged in a row, each depression having a shape that gradually widens from the opening (C1 direction side) to the bottom (C2 direction side). Specifically, the boiling surface 13 is composed of multiple depressions 13e arranged in a matrix in directions A and B. The multiple depressions 13e are recessed in the plate-shaped body 13f on the C2 direction side. The depressions 13e are frustoconical in shape, gradually widening from the C1 direction side to the C2 direction side. The depressions 13e have a bottom on the C2 direction side, an opening on the C1 direction side, and four tapered surfaces connecting the bottom and the opening. Shapes like the depressions 13e make it easy for bubbles to form (making them easy to initiate boiling), improving boiling heat transfer performance. Also, the cross-sectional shape of the space between the protrusions 13c shown in Figures 6 to 9 is similar to the cross-sectional shape of the depressions 13e.

[0042] The recess 13e has a width W4 and a height H4. The width W4 is the length of the opening of the recess 13e in directions A and B. The height H4 is the length of the recess 13e in direction C. In addition, each tapered surface (side) of the recess 13e is inclined at an angle θ4 with respect to the AB plane. The recesses 13e are arranged side by side in directions A and B with a pitch P4. The pitch P4 is the distance between adjacent recesses 13e in directions A and B. In the examples shown in Figures 10 and 11, the pitch P4 and the height H4 are the same length, but are not particularly limited. Also, in the examples shown in Figures 10 and 11, the width W4 is smaller than the pitch P4 and height H4, but is not particularly limited. For example, the width W4 is approximately 0.4 mm, the height H4 is approximately 0.5 mm, the pitch P4 is approximately 0.5 mm, and the inclination angle θ4 is approximately 70 degrees.

[0043] (Fifth example of the boiling surface) Figures 12 and 13 show the fifth example. The boiling surface portion 13 of the fifth example is the same as the boiling surface portion 13 of the second example, but without the bottom plate 12b. The boiling surface portion 13 of the fifth example has the same configuration as the boiling surface portion 13 of the second example, except that the bottom plate 12b is not provided. That is, the boiling surface portion 13 of the fifth example is made up of multiple protrusions 13c arranged in a row, each having a shape that gradually widens from the base end (C2 direction side) to the tip (C1 direction side). Specifically, the boiling surface portion 13 is made up of multiple protrusions 13c arranged in a matrix in the A direction and the B direction. The protrusions 13c of the fifth example are directly bonded to the surface 11b of the mounting portion 11 by additive manufacturing.

[0044] (Manufacturing method for boiling condensers) A method for manufacturing the cooler 100 according to the first embodiment will be described with reference to Figures 14 to 16.

[0045] As shown in Figure 14, the manufacturing method of the cooler 100 includes a step of forming a condensing section 20. The step of forming the condensing section 20 includes a step of forming the condensing section 20 by joining a refrigerant passage component 21b, which will become a refrigerant passage 21, and an external passage component 22b, which will become an external passage 22. As shown in Figure 15, the manufacturing method of the cooler 100 includes a step of forming a boiling section 10. The step of forming the boiling section 10 includes a step of forming a boiling surface 13 and a step of joining a mounting section 11 to the condensing section 20.

[0046] In the first embodiment, the step of forming the boiling surface 13 is a step of forming at least a portion of the boiling surface 13 by additive manufacturing. Specifically, the step of forming the boiling surface 13 includes a step of forming at least a portion of the boiling surface 13 by additive manufacturing using metal powder. More specifically, the step of forming the boiling surface 13 includes a step of forming at least a portion of the boiling surface 13 by powder bed fusion bonding as additive manufacturing. That is, the step of forming the boiling surface 13 includes a step of forming a layer of metal powder and a step of irradiating the formed portion of the formed metal powder layer with a high-energy beam to sinter the metal powder in the formed portion, thereby forming at least a portion of the boiling surface 13. At this time, minute irregularities originating from the sintering of the metal powder by the high-energy beam are formed on the surface of the boiling surface 13 as an additively manufactured body.

[0047] Furthermore, in the first example, the process of forming the boiling surface 13 includes forming linear protrusions 13a by additive manufacturing such that multiple linear protrusions 13a extending in direction A are arranged in direction B. In the second, third, and fifth examples, the process of forming the boiling surface 13 includes forming multiple protrusions 13c by additive manufacturing such that multiple protrusions 13c having a shape that gradually widens from the base to the tip are arranged in a matrix. In the second and fifth examples, the process of forming the boiling surface 13 includes forming multiple protrusions 13c by additive manufacturing such that multiple protrusions 13c are arranged in a matrix in directions A and B. Note that in the first, second, and third examples, the bottom plate 13b is also formed by additive manufacturing, while in the fifth example, the bottom plate 13b is not formed. Furthermore, in the case of the second and fifth examples described above, the step of forming the boiling surface portion 13 includes a step of forming multiple protrusions 13c by additive manufacturing such that the protrusions 13c are arranged at a pitch smaller than the width of the protrusions 13c.

[0048] Furthermore, in the third example, the step of forming the boiling surface portion 13 includes a step of forming linear protrusions 13d and protrusions 13c by additive manufacturing such that multiple linear protrusions 13d extending in direction A are arranged in direction B, and multiple protrusions 13c are arranged on the linear protrusions 13d and between the linear protrusions 13d in direction B. Furthermore, in the fourth example, the step of forming the boiling surface portion 13 includes a step of forming an additively manufactured body including depressions 13e by additive manufacturing such that multiple depressions 13e having a shape that gradually widens from the opening towards the bottom are arranged in a row. Note that in the first to fifth examples, the entire boiling surface portion 13 is formed by additive manufacturing.

[0049] Furthermore, in the first embodiment, the step of forming the boiling surface 13 includes a step of forming the boiling surface 13 without performing blast treatment after additive manufacturing. That is, the boiling surface 13 is used in the cooler 100 in the surface state formed by additive manufacturing without surface processing treatment by blast treatment. In other words, the boiling surface 13 is used in the cooler 100 in a state in which minute irregularities originating from the sintering of metal powder by a high-energy beam are present. However, heat treatment may be performed on the boiling surface 13.

[0050] Furthermore, the step of forming the boiling surface portion 13 includes a step of joining the boiling surface portion 13 to the surface 11b of the mounting portion 11 opposite to the mounting surface 11a of the heating element HS. The step of joining the boiling surface portion 13 to the surface 11b is not particularly limited, but includes a step of joining the boiling surface portion 13 to the surface 11b by direct additive manufacturing, or a step of joining the boiling surface portion 13, which is an additively manufactured body formed by additive manufacturing, to the surface 11b by a joining method such as brazing, welding, or friction stir welding. In the first to fourth examples above, the boiling surface portion 13 may be joined to the surface 11b by any of these methods. In the fifth example above, the boiling surface portion 13 is directly joined to the surface 11b by additive manufacturing. After joining the boiling surface portion 13 to the surface 11b, the step of joining the mounting portion 11 to the condensation portion 20 is performed.

[0051] The step of joining the mounting portion 11 to the condensing portion 20 includes the step of joining the mounting portion 11 to the condensing portion 20 by welding. In this step, for example, all four sides of the mounting portion 11 that are in contact with the condensing portion 20 are welded. The joining of the mounting portion 11 to the condensing portion 20 by welding forms the housing portion 12. This forms the boiling portion 10, and the cooler 100 is completed. Then, as shown in Figure 16, the heating element HS is attached to the mounting surface 11a of the mounting portion 11.

[0052] (Effects of the first embodiment) In the first embodiment, the following effects can be obtained.

[0053] By additive manufacturing, a boiling surface 13 with high boiling heat transfer performance can be obtained, and by using additive manufacturing, the boiling surface 13 can be obtained in a simple process without going through many separate steps. As a result, a boiling surface 13 with high boiling heat transfer performance can be obtained in a simple process.

[0054] Furthermore, in the first embodiment, a boiling surface 13 with minute irregularities on its surface can be obtained by additive manufacturing using metal powder. As a result, boiling can be promoted by the minute irregularities on the surface, so a boiling surface 13 with higher boiling heat transfer performance can be obtained.

[0055] Furthermore, in the first embodiment, a boiling surface 13 with minute irregularities on its surface can be easily obtained by powder bed fusion bonding, making it possible to easily obtain a boiling surface 13 with higher boiling heat transfer performance.

[0056] Furthermore, in the first embodiment, by forming multiple protrusions 13c, each having a shape that gradually widens from the base to the tip, by additive manufacturing, a boiling surface 13 can be obtained that has a space between the protrusions 13c that can be filled with refrigerant. As a result, when the refrigerant boils on and around the protrusions 13c, the refrigerant filling the space between the protrusions 13c can be supplied quickly, thereby suppressing the drying of the boiling protrusions 13c and their surroundings. This avoids a situation where boiling is inhibited due to the drying of the protrusions 13c and their surroundings, thus improving the boiling heat transfer performance of the boiling surface 13. In addition, multiple protrusions 13c having a shape that gradually widens from the base to the tip are difficult to form by machining such as cutting, but can be easily formed by additive manufacturing.

[0057] Furthermore, in the first embodiment, by forming multiple protrusions 13c in a matrix-like arrangement in directions A and B that are substantially orthogonal to each other within a plane substantially parallel to the boiling surface 13, a boiling surface 13 with a well-balanced arrangement of protrusions 13c can be obtained. As a result, since the protrusions 13c are not unevenly distributed, the effect of improving the boiling heat transfer performance of the boiling surface 13 by filling the spaces between the protrusions 13c with refrigerant can be exerted evenly at any position on the boiling surface 13.

[0058] Furthermore, in the first embodiment, multiple linear protrusions 13d extending in direction A in a plane substantially parallel to the boiling surface portion 13 are arranged in a direction B substantially perpendicular to direction A in a plane substantially parallel to the boiling surface portion 13, and multiple protrusions 13c are arranged on the linear protrusions 13d and between the linear protrusions 13d in direction B, thereby forming the linear protrusions 13d and protrusions 13c by additive manufacturing. This makes it possible to obtain a boiling surface portion 13 that combines protrusions 13c having a shape that gradually widens from the base to the tip with linear protrusions 13d. As a result, it is possible to increase the heat transfer area with the linear protrusions 13d while improving the boiling heat transfer performance of the boiling surface portion 13 by filling the space between the protrusions 13c with refrigerant.

[0059] Furthermore, in the first embodiment, multiple protrusions 13c are arranged at a pitch P2 smaller than the width W2 of the protrusions 13c. If the pitch P2 of the protrusions 13c becomes too large, the number of protrusions 13c that can be placed on the boiling surface 13 decreases, resulting in a lower boiling heat transfer performance of the boiling surface 13. Therefore, by configuring it as described above, it is possible to suppress the pitch P2 of the protrusions 13c from becoming too large, and thus prevent the number of protrusions 13c that can be placed on the boiling surface 13 from decreasing too much. As a result, the boiling heat transfer performance of the boiling surface 13 can be appropriately set.

[0060] Furthermore, in the first embodiment, when obtaining a boiling surface 13 having multiple linear protrusions 13a arranged in a row, the boiling surface 13 can be made into a simple shape. Also, when obtaining a boiling surface 13 having multiple depressions 13e arranged in a row, since the depressions 13e have a shape that gradually widens from the opening where bubbles are easily generated by boiling towards the bottom, the boiling heat transfer performance of the boiling surface 13 can be improved.

[0061] Furthermore, in the first embodiment, by forming the boiling surface 13 without blasting after additive manufacturing, it is possible to avoid the removal of minute irregularities on the surface of the boiling surface 13 by blasting, thereby obtaining a boiling surface 13 with high boiling heat transfer performance. In addition, the manufacturing process of the boiling type cooler 100 can be simplified compared to the case where blasting is performed after additive manufacturing.

[0062] (First embodiment, first modified example) Referring to Figure 17, a first modification of the first embodiment described above will be explained. In this first modification, unlike the first embodiment in which the mounting portion 11 is joined to the condensing portion 20 by welding, an example will be described in which the mounting portion 11 is joined to the condensing portion 20 by brazing.

[0063] As shown in Figure 17, the step of joining the mounting portion 11 to the condensing portion 20 includes the step of joining the mounting portion 11 to the condensing portion 20 by brazing. In this case, a brazing sheet 30 having a core material and brazing material provided on both sides of the core material is provided between the condensing portion 20 and the mounting portion 11. The mounting portion 11 is brazed to the condensing portion 20 via the brazing sheet 30. In the example shown in Figure 17, a recess 11c is provided in the mounting portion 11 instead of the hole 20a in the first embodiment. When the mounting portion 11 is brazed to the condensing portion 20, a housing portion 12 is formed by the recess 11c. This forms the boiling portion 10, and the cooler 100 is completed. Then, the heating element HS is attached to the mounting surface 11a of the mounting portion 11.

[0064] (Second modified example of the first embodiment) Referring to Figure 18, a second modification of the first embodiment described above will be explained. In this second modification, unlike the first embodiment in which the mounting portion 11 is joined to the condensing portion 20 by welding, an example will be described in which the mounting portion 11 is joined to the condensing portion 20 by screw fastening.

[0065] As shown in Figure 18, the step of joining the mounting part 11 to the condensing part 20 includes the step of joining the mounting part 11 to the condensing part 20 by screw fastening. In this case, the mounting part 11 is provided with an insertion hole for a screw 40, and the condensing part 20 is provided with a screw hole for the screw 40. In addition, a sealing member 50 such as an O-ring is provided between the condensing part 20 and the mounting part 11. With the sealing member 50 in between, the mounting part 11 is screwed to the condensing part 20 by the screw 40. This forms the housing part 12 and the boiling part 10, and the cooler 100 is completed. In the case of screw fastening, the sealing member 50 can also seal the refrigerant inside the housing part 12. Then, the heating element HS is attached to the mounting surface 11a of the mounting part 11.

[0066] [Second Embodiment] Next, with reference to Figures 19 to 21, the configuration of the boiling type cooler 200 (hereinafter referred to as "cooler 200") according to the second embodiment of the present invention will be described. In the second embodiment, unlike the first embodiment in which the boiling section 10 and the condensing section 20 are integrated, an example in which the boiling section 210 and the condensing section 220 are separate will be described. Note that the same reference numerals will be used for components similar to those in the first embodiment, and their descriptions will be omitted.

[0067] As shown in Figures 19 to 21, the cooler 200 comprises a boiling section 210, a condensing section 220, and a connecting section 260. The boiling section 210 boils the refrigerant by heat exchange with the heating element HS. The condensing section 220 condenses the refrigerant boiled in the boiling section 210 and returns it to the boiling section 210. The connecting section 260 is a connecting pipe that connects and communicates the boiling section 210 and the condensing section 220. In the second embodiment, the boiling section 210 and the condensing section 220 are separate.

[0068] The boiling section 210 includes a mounting section 11 and a storage section 212 (see Figure 21). The storage section 212 contains liquid refrigerant. The storage section 212 is partitioned by a recess 214a formed in the main body 214 of the boiling section 210 and the surface 11b of the mounting section 11. The storage section 212 is provided as a box-shaped space. Within the storage section 212, the boiling surface 13 is in contact with the liquid refrigerant. The boiling surface 13 is the same as in the first embodiment described above, so a detailed explanation will not be given, but it is formed by additive manufacturing.

[0069] The condensing section 220 is composed of a plate fin type heat exchanger. The condensing section 220 includes a refrigerant passage 221 and an external passage 222. The refrigerant passage 221 and the external passage 222 are arranged alternately with a partition plate in between. The refrigerant passage 221 is a flow path for refrigerant. The refrigerant passage 221 communicates with the housing section 212 of the boiling section 10 via a connection section 260. Corrugated fins extending in the X direction are arranged inside the refrigerant passage 221. The external passage 222 is a flow path for external fluid. The external passage 222 is open to the outside. Corrugated fins 222a extending in the Y direction are arranged inside the external passage 222.

[0070] When heat from the heating element HS is transferred to the boiling surface 13 via the mounting portion 11, the liquid refrigerant in the containment portion 212 is heated and boils. The refrigerant vaporized by boiling moves into the refrigerant passage 221, which communicates with the containment portion 212 via the connection portion 260, and is cooled and condensed by the external fluid flowing through the external passage 222. The refrigerant liquefied by condensation moves through the refrigerant passage 221 and the connection portion 260 and returns to the containment portion 212. In this way, the refrigerant sealed in the cooler 200 circulates between the boiling portion 210 and the condensing portion 220. This cools the heating element HS.

[0071] (Manufacturing method for boiling condensers) A method for manufacturing the cooler 200 according to the second embodiment will be described with reference to Figures 22 to 24.

[0072] As shown in Figure 22, the manufacturing method of the cooler 200 includes a step of forming a boiling section 210. The step of forming the boiling section 210 includes a step of forming a boiling surface section 13 and a step of joining a mounting section 11 to the main body 214. The step of forming the boiling surface section 13 is the same as in the first embodiment described above, so a detailed explanation will not be given, but it is a step of forming at least a part of the boiling surface section 13 by additive manufacturing.

[0073] The step of joining the mounting portion 11 to the main body 214 includes the step of joining the mounting portion 11 to the main body 214 by welding. In this step, for example, all four sides of the mounting portion 11 that are in contact with the main body 214 are welded. The joining of the mounting portion 11 to the main body 214 by welding forms the housing portion 212. This forms the boiling portion 210. As shown in Figure 23, the manufacturing method of the cooler 200 includes the step of forming the condensing portion 220. The step of forming the condensing portion 220 includes the step of joining the refrigerant passage component 221b, which will become the refrigerant passage 221, and the external passage component 222b, which will become the external passage 222, to form the condensing portion 220. The manufacturing method of the cooler 200 also includes the step of joining the boiling portion 210 and the condensing portion 220 via the connecting portion 260. After that, the cooler 200 is completed. Then, as shown in Figure 24, the heating element HS is attached to the mounting surface 11a of the mounting portion 11.

[0074] The other configurations of the second embodiment are the same as those of the first embodiment described above.

[0075] (Effects of the second embodiment) In the manufacturing method of the boiling type cooler 200 according to the second embodiment, at least a portion of the boiling surface portion 13 that is provided on the surface 11b opposite to the mounting surface 11a of the heating element HS and is in contact with the refrigerant is formed by additive manufacturing, thereby, similar to the first embodiment, a boiling surface portion 13 with high boiling heat transfer performance can be obtained in a simple process.

[0076] Other effects of the second embodiment are the same as those of the first embodiment described above.

[0077] (First modified example of the second embodiment) Referring to Figure 25, a first modified example of the second embodiment described above will be explained. In this first modified example, unlike the second embodiment in which the mounting portion 11 is joined to the main body 214 by welding, an example in which the mounting portion 11 is joined to the main body 214 by brazing will be described.

[0078] As shown in Figure 25, the step of joining the mounting portion 11 to the main body 214 includes the step of joining the mounting portion 11 to the main body 214 by brazing. In this case, a brazing sheet 230 having a core material and brazing material provided on both sides of the core material is provided between the main body 214 and the mounting portion 11. The mounting portion 11 is brazed to the main body 214 via the brazing sheet 230. Once the mounting portion 11 is brazed to the main body 214, the housing portion 212 is formed. This forms the boiling portion 210, and the cooler 200 is completed. Then, the heating element HS is attached to the mounting surface 11a of the mounting portion 11.

[0079] (Second modified example of the second embodiment) Referring to Figure 26, a second modification of the first embodiment described above will be explained. In this second modification, unlike the first embodiment in which the mounting portion 11 is joined to the main body 214 by welding, an example will be described in which the mounting portion 11 is joined to the main body 214 by screw fastening.

[0080] As shown in Figure 26, the step of joining the mounting portion 11 to the main body 214 includes the step of joining the mounting portion 11 to the main body 214 by screw fastening. In this case, the mounting portion 11 is provided with an insertion hole for a screw 240, and the main body 214 is provided with a screw hole for the screw 240. In addition, a sealing member 250 such as an O-ring is provided between the main body 214 and the mounting portion 11. With the sealing member 250 in between, the mounting portion 11 is screwed to the main body 214 with the screw 240. This forms the housing portion 212 and the boiling portion 210, and the cooler 200 is completed. Even in the case of screw fastening, the sealing member 250 can seal the refrigerant inside the housing portion 212. Then, the heating element HS is attached to the mounting surface 11a of the mounting portion 11.

[0081] [Examples] The measurement results of the boiling heat transfer performance at the boiling surface will be explained with reference to Figures 27 to 31.

[0082] In Figures 27 to 31, Examples 1 to 4 are test coolers equipped with boiling surfaces in the shapes of Examples 1 to 4, respectively, formed by additive manufacturing. The dimensions of the protrusions, linear protrusions, and depressions in the boiling surfaces of Examples 1 to 4 were the same as those described in the First Embodiment. The boiling surfaces of Examples 1 to 4 were formed by powder bed fusion bonding. The Comparative Example is a test cooler equipped with a boiling surface in the same shape as Example 1, formed by extrusion molding. The material of the boiling surfaces in Examples 1 to 4 and the Comparative Example was the same (aluminum). The refrigerant was hydrofluorocarbon.

[0083] The boiling heat transfer performance of the coolers in Examples 1-4 and the Comparative Example was measured under conditions where they were heated with a test heating element. During this measurement, a predetermined airflow was blown into the external passage of the condensing section. The refrigerant temperature inside the housing and the maximum temperature of the mounting surface were measured, and the temperature difference ΔT between the refrigerant temperature inside the housing and the maximum temperature of the mounting surface was obtained as an indicator of boiling heat transfer performance. A smaller temperature difference ΔT indicates a higher heat transfer coefficient for boiling and higher boiling heat transfer performance (cooling performance) at the boiling surface. Furthermore, the temperature difference ΔT was obtained for each heat flux by gradually changing the heat generation (heat flux) of the heating element.

[0084] Figures 27 to 30 show graphs of the individual measurement results for Examples 1 to 4. Figure 31 shows a graph summarizing the measurement results for Examples 1 to 4. In each graph from Figures 27 to 31, the horizontal axis represents the heat flux of the heating element [W / cm²]. 2 The graph shows the temperature difference ΔT[K] on the vertical axis.

[0085] As is clear from the graphs in Figures 27 to 30, the boiling surfaces of Examples 1 to 4 show a lower temperature difference ΔT and higher boiling heat transfer performance (cooling performance) compared to the conventional boiling surface of the Comparative Example, which was not manufactured using additive manufacturing. Furthermore, focusing on the boiling surfaces of Example 1 and the Comparative Example, despite having similar shapes, the boiling surface of Example 1 shows higher boiling heat transfer performance. This is presumed to be because the minute irregularities formed on the surface of the boiling surface by additive manufacturing (powder bed fusion) contribute to promoting boiling. Specifically, it is presumed that the irregularities on the surface of the boiling surface function as bubble generation points (boiling initiation points), resulting in higher boiling heat transfer performance. From the measurement results, it is considered that a boiling surface with high boiling heat transfer performance can be obtained using additive manufacturing.

[0086] Furthermore, as can be seen from the graph in Figure 31, in the low heat flux region, the temperature difference ΔT does not change significantly for any of the boiling surfaces in Examples 1 to 4, and therefore the boiling heat transfer performance does not change significantly. On the other hand, in the high heat flux region, the boiling surfaces of Examples 2 to 4 have a lower temperature difference ΔT than the boiling surface of Example 1, and thus exhibit higher boiling heat transfer performance (cooling performance). This is presumed to be because the shape of the boiling surfaces in Examples 2 to 4 had an effect in the high heat flux region.

[0087] In other words, it is presumed that the effect of arranging multiple protrusions having a shape that gradually widens from the base to the tip was achieved in Examples 2 and 3. Specifically, the boiling surface of Examples 2 and 3 has a shape that allows refrigerant to be filled into the space between the protrusions. Therefore, when the refrigerant boils on and around the protrusions, the refrigerant filling the space between the protrusions is supplied quickly, so it is presumed that the protrusions and their surroundings do not dry out easily, and the boiling heat transfer performance is improved. In Example 4, it is presumed that the effect of arranging multiple depressions having a shape that gradually widens from the opening to the bottom, which makes it easy for bubbles to form, was achieved. Furthermore, it is presumed that the boiling heat transfer performance did not change much in the region of low heat flux, as the effect of these shapes is not so strongly exhibited in that region. From the measurement results, it is considered that a boiling surface with multiple protrusions having a shape that gradually widens from the base to the tip, and a boiling surface with multiple depressions having a shape that gradually widens from the opening to the bottom, can be obtained to obtain a boiling surface with higher boiling heat transfer performance.

[0088] Furthermore, as can be seen from the graph in Figure 31, in the region of high heat flux, the boiling surface of Example 2 has a lower temperature difference ΔT than the boiling surface of Example 3, indicating higher boiling heat transfer performance (cooling performance). This is presumed to be because the boiling surface of Example 2, which has protrusions but no linear protrusions, exhibits a more rapid supply of the refrigerant compared to the boiling surface of Example 3, which has both linear protrusions and other protrusions. From the measurement results, it is considered that a boiling surface with multiple protrusions arranged without linear protrusions can be obtained with even higher boiling heat transfer performance.

[0089] [Differentiation] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims rather than by the description of the embodiments above, and further includes all modifications (exceptions) within the meaning and scope equivalent to the claims.

[0090] For example, the first and second embodiments described above show examples of horizontal boiling condensers with a horizontal boiling surface, but the present invention is not limited thereto. In the present invention, the boiling condenser may be a vertical type with a vertical boiling surface. Furthermore, the boiling condensers of the first and second embodiments described above are merely examples, and the shape and arrangement of the various parts of the boiling condenser are not particularly limited.

[0091] Furthermore, while the first and second embodiments described above show examples in which the boiling surface is formed by powder bed fusion as an additive manufacturing method, the present invention is not limited thereto. In the present invention, the boiling surface may be formed by additive manufacturing methods other than powder bed fusion.

[0092] Furthermore, while the first and second embodiments described above show examples in which multiple protrusions are formed by additive manufacturing so that they are arranged in a matrix, the present invention is not limited thereto. In the present invention, multiple protrusions may be formed by additive manufacturing so that they are arranged in a staggered (zigzag) pattern.

[0093] Furthermore, while the first and second embodiments described above show examples in which multiple protrusions are formed by additive manufacturing with a pitch smaller than the width of the protrusion, the present invention is not limited thereto. In the present invention, multiple protrusions may be formed by additive manufacturing with a pitch greater than or equal to the width of the protrusion.

[0094] Furthermore, while the first and second embodiments described above show examples in which the boiling surface formation step includes a step of forming the boiling surface without performing blast treatment after additive manufacturing, the present invention is not limited thereto. In the present invention, the boiling surface formation step may include a step of forming the boiling surface by performing blast treatment after additive manufacturing.

[0095] Furthermore, while the first and second embodiments described above show examples in which a boiling surface portion having multiple protrusions arranged in a shape that gradually widens from the base to the tip is formed by additive manufacturing, the present invention is not limited thereto. In the present invention, a boiling surface portion having multiple protrusions arranged in a shape that gradually widens from the base to the tip may be formed by machining or a combination of machining and additive manufacturing.

[0096] Furthermore, while the first and second embodiments described above show an example where the projection, which gradually widens from the base to the tip, is in the shape of a frustum of a square, the present invention is not limited thereto. In the present invention, the projection, which gradually widens from the base to the tip, may be in the shape of a frustum other than a frustum of a square (such as another frustum of a pyramidal pyramid or a frustum of a cone).

[0097] Furthermore, while the first and second embodiments described above show examples where the entire boiling surface is formed by additive manufacturing, the present invention is not limited thereto. In the present invention, it is sufficient that at least a portion of the boiling surface is formed by additive manufacturing. For example, the boiling surface may be formed by additive manufacturing of protrusions on a base plate formed by a method other than additive manufacturing. [Explanation of symbols]

[0098] 10, 210 Boiling part 11a Mounting surface 11b The side opposite the mounting surface 13 Boiling surface part 13a, 13d linear projections 13c protrusion 13e Indentation 20, 220 Condensing section 100, 200 cooler (boiling type cooler) HS heating element

Claims

1. A method for manufacturing a boiling type cooler comprising a boiling section that vaporizes a refrigerant by heat exchange with a heating element, and a condensing section that condenses the vaporized refrigerant and returns the condensed refrigerant to the boiling section, The process of forming the condensed portion, The process includes forming the boiling section, which includes a mounting section to which the condensing section is attached, The step of forming the boiling portion includes the step of forming a boiling surface portion that comes into contact with the refrigerant on the surface of the mounting portion that is opposite to the mounting surface to which the heating element is attached. The step of forming the boiling surface includes the step of forming a plurality of protrusions that gradually increase in thickness from the base end to the tip, A method for manufacturing a boiling type cooler, comprising the step of forming a plurality of protrusions, wherein linear protrusions extending in a first direction in a plane substantially parallel to the boiling surface are arranged in a plurality of directions in a second direction substantially perpendicular to the first direction in a plane substantially parallel to the boiling surface, and the step of forming a plurality of protrusions arranged on the linear protrusions and between the linear protrusions in the second direction.

2. The method for manufacturing a boiling type cooler according to claim 1, wherein the step of forming the boiling surface portion includes a step of forming at least a part of the boiling surface portion by additive manufacturing using metal powder.

3. The method for manufacturing a boiling type cooler according to claim 2, wherein the step of forming the boiling surface portion includes a step of forming at least a part of the boiling surface portion by powder bed fusion bonding as additive manufacturing.

4. The method for manufacturing a boiling type cooler according to claim 1, wherein the step of forming a plurality of protrusions includes the step of forming a plurality of protrusions arranged in a matrix in the first direction and the second direction.

5. The method for manufacturing a boiling type cooler according to any one of claims 1 to 4, wherein the step of forming a plurality of protrusions includes the step of forming a plurality of protrusions arranged at a pitch smaller than the width of the protrusions.

6. The method for manufacturing a boiling type cooler according to any one of claims 1 to 5, wherein the step of forming the boiling surface portion includes a step of forming the boiling surface portion without performing a blast treatment after additive manufacturing.

7. The method for manufacturing a boiling type cooler according to any one of claims 1 to 6, wherein the step of forming a plurality of protrusions includes the step of forming a plurality of truncated pyramidal protrusions in a row.

8. A method for manufacturing a boiling type cooler according to any one of claims 1 to 7, wherein the distance between the tips of adjacent protrusions is less than the width of the tip of one protrusion, and the distance between the base ends of adjacent protrusions is greater than the width of the tip of one protrusion.

9. The method for manufacturing a boiling type cooler according to claim 1, wherein the step of forming a plurality of protrusions includes the step of forming a plurality of protrusions in a staggered pattern.

10. The method for manufacturing a boiling type cooler according to claim 1, wherein the step of forming the boiling surface portion includes a step of performing a blast treatment after additive manufacturing to form the boiling surface portion.

11. The method for manufacturing a boiling type cooler according to claim 1, wherein the step of forming the boiling portion includes a step of joining the mounting portion to the condensing portion by welding, brazing, or screw fastening.

12. A boiling section that vaporizes the refrigerant through heat exchange with a heating element, The system comprises a condensation section that condenses the vaporized refrigerant and returns the condensed refrigerant to the boiling section, The boiling section includes a mounting section to which the condensing section is attached. The aforementioned mounting portion is The mounting surface on which the heating element is attached, It has a boiling surface portion formed on the surface opposite to the mounting surface and in contact with the refrigerant, Multiple protrusions are formed on the boiling surface, gradually increasing in thickness from the base to the tip. A boiling condenser, wherein the boiling surface has multiple linear protrusions extending in a first direction in a plane substantially parallel to the boiling surface, arranged in a second direction substantially perpendicular to the first direction in a plane substantially parallel to the boiling surface, and multiple protrusions are arranged on the linear protrusions and between the linear protrusions in the second direction.

13. The boiling type cooler according to claim 12, wherein a plurality of the protrusions are formed on the boiling surface such that they are arranged in a matrix in the first and second directions.

14. The boiling type cooler according to claim 12 or 13, wherein a plurality of the protrusions are formed on the boiling surface at a pitch smaller than the width of the protrusions.

15. The boiling condenser according to any one of claims 12 to 14, wherein the projection is frustum-shaped.

16. A boiling type cooler according to any one of claims 12 to 15, wherein the distance between the tips of adjacent protrusions is less than the width of the tip of one protrusion, and the distance between the base ends of adjacent protrusions is greater than the width of the tip of one protrusion.

17. The boiling type cooler according to claim 12, wherein a plurality of the protrusions are formed in a staggered pattern on the boiling surface.

18. The boiling type cooler according to claim 12, wherein the mounting portion is joined to the condensing portion by welding, brazing, or screw fastening.

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