Cold plate

Abstract

To provide a cold plate which can improve cooling capability without increasing the size of a server.SOLUTION: A cold plate includes a casing which is mounted on the outer surface of a heating element, boils a coolant circulated inside and draws heat from the heating element, and a plurality of fins which are arranged at intervals in a second direction crossing a first direction, in the casing. The fin projects in the first direction from the bottom surface along the outer surface among the inner surfaces of the casing, and extends in a direction crossing both the first direction and the second direction. The plurality of fins form a flow channel capable of circulating the coolant between the adjacent fins. The plurality of fins include a plurality of first fins extending to the downstream end from the upstream end of the flow channel, and a plurality of second fins arranged between the adjacent first fins. The height in the first direction of the second fin on the upstream side in a circulation direction of the flow channel is higher than the height in the first direction of the second fin on the downstream side in the circulation direction.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a cold plate. [Background technology]

[0002] Electronic devices such as CPUs and GPUs installed in servers generate heat during operation. Cold plates are used to cool these heat-generating devices. A refrigerant flows inside the cold plate. The refrigerant inside the cold plate removes heat from the heat-generating device, thereby cooling it. For example, there is a boiling cooling type cold plate, which boils the refrigerant and removes heat from the heat-generating device using the heat of vaporization.

[0003] Furthermore, Patent Document 1 below discloses a technology for increasing the heat transfer area by providing fins in the flow path through which the refrigerant flows. By forming such fins in the cold plate, the heat transfer area increases, and it is expected that the cooling capacity will improve. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-35295 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when fins are installed inside the cold plate, backflow and unstable flow may occur between the fins, which may hinder heat transfer from the heat source to the refrigerant and reduce cooling performance.

[0006] Furthermore, if the flow path width between the fins is narrow, in the upstream region where the bubble volume is small, the bubbles flatten, expanding the thin liquid film region. This liquid film region promotes heat transfer from the heating element to the refrigerant. On the other hand, in the downstream region where the bubble volume is large, the bubbles flatten further, expanding the dryout region where heat transfer performance is poor. As a result, heat transfer performance deteriorates from the upstream side to the downstream side, and there is a risk of cooling performance decreasing.

[0007] Another method to prevent unstable flow is to change the shape of the casing that contains the refrigerant, gradually expanding the space above the fins toward the downstream side, making it easier for air bubbles to escape into the space above the fins as the amount of steam increases due to boiling. However, this method results in a larger cold plate, which can make it difficult to install in a server.

[0008] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a cold plate that can improve cooling capacity without increasing the size of the server. [Means for solving the problem]

[0009] In order to solve the above problem, the cold plate of the present disclosure comprises a casing arranged adjacent to a heating element in a first direction, attached to the outer surface of the heating element, and configured to boil a refrigerant flowing therethrough to remove heat from the heating element, and a plurality of fins arranged within the casing at intervals in a second direction intersecting the first direction, wherein the fins protrude in the first direction from a bottom surface of the inner surface of the casing that is aligned with the outer surface, and extend in a direction intersecting both the first direction and the second direction, the plurality of fins forming a flow path between adjacent fins through which the refrigerant can flow, the plurality of fins including a plurality of first fins extending from the upstream end to the downstream end of the flow path and a plurality of second fins arranged between adjacent first fins, and wherein the height in the first direction of the second fins on the upstream side of the flow path in the flow direction is greater than the height in the first direction of the second fins on the downstream side of the flow direction of the flow path.

[0010] The cold plate of the present disclosure comprises a casing arranged adjacent to a heating element in a first direction and attached to the outer surface of the heating element, which removes heat from the heating element by boiling a refrigerant flowing inside, and a plurality of fins arranged within the casing at intervals in a second direction intersecting the first direction, wherein the fins protrude in the first direction from a bottom surface of the inner surface of the casing that is along the outer surface and extend in a direction intersecting both the first direction and the second direction, and the plurality of fins form flow paths between adjacent fins through which the refrigerant can flow, and the height of the fins in the first direction on the upstream side of the flow path in the flow direction is greater than the height of the fins in the first direction on the downstream side of the flow direction. [Effects of the Invention]

[0011] The cold plate of the present disclosure can improve cooling performance. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a plan view of a cold plate according to the first embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 2 is a plan view of a fin according to the first embodiment of the present disclosure. [Figure 4] FIG. 2 is a front view of a fin according to the first embodiment of the present disclosure. [Figure 5] FIG. 2 is a side view of a fin according to the first embodiment of the present disclosure. [Figure 6] 3A to 3C are diagrams illustrating the function of a fin according to the first embodiment of the present disclosure. [Figure 7] 3A to 3C are diagrams illustrating the function of a fin according to the first embodiment of the present disclosure. [Figure 8] FIG. 10 is a plan view of a fin according to a second embodiment of the present disclosure. [Figure 9] FIG. 10 is a front view of a fin according to a second embodiment of the present disclosure. [Figure 10]FIG. 10 is a side view of a fin according to a second embodiment of the present disclosure. [Figure 11] FIG. 10 is a plan view of a fin according to a third embodiment of the present disclosure. [Figure 12] FIG. 10 is a front view of a fin according to a third embodiment of the present disclosure. [Figure 13] FIG. 10 is a side view of a fin according to a third embodiment of the present disclosure. [Figure 14] FIG. 10 is a plan view of a fin according to a fourth embodiment of the present disclosure. [Figure 15] FIG. 10 is a front view of a fin according to a fourth embodiment of the present disclosure. [Figure 16] FIG. 10 is a side view of a fin according to a fourth embodiment of the present disclosure. [Figure 17] FIG. 10 is a side view of a fin according to a modified example of the fourth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] First Embodiment A cold plate 1 according to a first embodiment of the present disclosure will be described below with reference to FIGS. The server has multiple chips such as CPUs and GPUs on a substrate 2. These chips generate heat during operation. The cold plate 1 of the present disclosure is used to cool these chips. Hereinafter, these chips will be referred to as heat generating elements 3. These chips are an example of the heat generating elements 3.

[0014] The heating element 3 is disposed so as to extend in the horizontal direction. Hereinafter, the vertical direction may be referred to as the first direction D1. One of the horizontal directions may be referred to as the "second direction D2," and the horizontal direction perpendicular to the second direction D2 may be referred to as the "third direction D3." The first direction D1, the second direction D2, and the third direction D3 are perpendicular to one another.

[0015] 1 and 2, the cold plate 1 is placed on the heating element 3 from above and is arranged to extend horizontally in the same manner as the heating element 3. The cold plate 1 includes a casing 10, a flow path wall 20, and fins 30.

[0016] (Casing) The casing 10 is disposed adjacent to the heat generating element 3 in the first direction D1. The casing 10 can be filled with a refrigerant R that cools the heat generating element 3. The refrigerant R flows inside the casing 10. The casing 10 boils the refrigerant R to remove heat from the heat generating element 3. The casing 10 extends in the second direction D2 and the third direction D3. The casing 10 is formed in the shape of a rectangular plate with the second direction D2 as its longitudinal direction. Hereinafter, an imaginary plane that passes through the center of the casing 10 in the third direction D3 and extends in the first direction D1 and the second direction D2 will be referred to as a center plane C. The casing 10 is made of a heat-conductive material such as a metal material. The casing 10 includes a base plate 11 and a cover 12 .

[0017] The base plate 11 is attached to the outer surface 3a of the heating element 3 on the side opposite to the substrate 2 in the first direction D1. The base plate 11 extends in the second direction D2 and the third direction D3. The base plate 11 is formed in the shape of a rectangular plate with the second direction D2 as its longitudinal direction.

[0018] The cover 12 is superimposed on the base plate 11 from the opposite side to the heating element 3 in the first direction D1. The cover 12 is open towards the base plate 11 in the first direction D1. The cover 12 covers the flow path walls 20 and the fins 30, which will be described later. The cover 12 has side walls 13 and an upper wall 14. A total of four side walls 13 are provided along each edge of the base plate 11. The side walls 13 rise from the base plate 11 in the first direction D1. Hereinafter, of the side walls 13, a pair of side walls 13 facing in the second direction D2 will be referred to as first side walls 13a, and a pair of side walls 13 facing in the third direction D3 will be referred to as second side walls 13b.

[0019] A supply hole 15 is formed in one of the two first side walls 13a. The supply hole 15 penetrates the first side wall 13a in the second direction D2. The supply port 4 is connected to the supply hole 15. The supply port 4 supplies the refrigerant R into the casing 10. The refrigerant R is supplied into the casing 10 through the supply hole 15. In this embodiment, the supply hole 15 is formed in a circular shape. The center of the supply hole 15 is located on the central plane C.

[0020] The top wall 14 is provided at the end of each side wall 13 opposite the base plate 11 in the first direction D1. The top wall 14 closes the space surrounded by the four side walls 13. The top wall 14 extends in the second direction D2 and the third direction D3. The top wall 14 is formed in the shape of a rectangular plate with the second direction D2 as its longitudinal direction.

[0021] A discharge hole 16 is formed in the upper wall 14. The discharge hole 16 penetrates the upper wall 14 in the first direction D1. The discharge outlet extends in the second direction D2. The discharge hole 16 is connected to a discharge port 5. The discharge port 5 discharges the refrigerant R from inside the casing 10. The refrigerant R is discharged to the outside of the casing 10 through the discharge hole 16. A center line that passes through the center of the discharge hole 16 in the third direction D3 and extends in the second direction D2 is located on the center plane C.

[0022] (channel wall) When viewed from the first direction D1, the flow path walls 20 are arranged in pairs on both outer sides of the discharge holes 16 in the second direction D2. The flow path walls 20 extend in a third direction D3. The flow path walls 20 also protrude from the base plate 11 in the first direction D1 and connect the base plate 11 and the upper wall 14. The flow path walls 20 are also arranged at positions facing the first side wall 13a in the second direction D2. The flow of the refrigerant R supplied into the casing 10 is changed from the second direction D2 to the third direction D3 by the flow path walls 20.

[0023] (fin) The fins 30 are arranged in the casing 10 at intervals in the second direction D2. In this embodiment, the fins 30 are arranged at equal intervals in the second direction D2. The fins 30 extend in the third direction D3. The fins 30 protrude from a bottom surface 17a on the base plate 11 of the inner surface 17 of the casing 10 and connect the base plate 11 to the upper wall 14. The bottom surface 17a is aligned with the outer surface 3a of the heating element 3. The fins 30 form flow paths 6 between adjacent fins 30 in the casing 10, through which the refrigerant R can flow. The refrigerant R flows in the flow paths 6 from the second side wall 13b toward the discharge holes 16 in the third direction D3. Hereinafter, the flow direction Df of the flow paths 6 will be simply referred to as the flow direction Df. In this embodiment, the flow direction Df coincides with the third direction D3. Moreover, the upstream side Dfu in the flow direction Df will be simply referred to as the upstream side Dfu, and the downstream side Dfd in the flow direction Df will be simply referred to as the downstream side Dfd. The width W1 of the flow channel 6 in the second direction D2 is constant at all positions in the flow direction Df.

[0024] Furthermore, the fins 30 are formed of, for example, the same material as the casing 10. That is, the fins 30 are formed of, for example, a heat-conductive material such as a metal material. The width W2 of the fins 30 in the second direction D2 is constant at all positions in the flow direction Df. The width W2 of the fins 30 is smaller than the distance between the fins 30 (the width W1 of the flow path 6). Furthermore, the height H of each fin 30 in the first direction D1 is designed to be larger than the width W2 of the fin 30 and the distance between the fins 30 (the width W1 of the flow path 6) at least at the end of each fin 30 on the most upstream side Dfu.

[0025] In this embodiment, the fins 30 are provided in pairs on both sides of the central plane C in the third direction D3. These pairs of fins 30 are formed symmetrically with respect to the central plane C. Each pair of fins 30 includes a plurality of first fins 31 and a plurality of second fins 32. In this embodiment, the first fins 31 and the second fins 32 both extend from the upstream end 6a to the downstream end 6b of the flow channel 6 in the flow direction Df. That is, the length L1 of the first fin 31 in the second direction D2 and the length L2 of the second fin 32 in the second direction D2 are equal.

[0026] (First fin) The first fins 31 extend from the upstream end 6a to the downstream end 6b of the flow path 6. The first fins 31 adjacent to each other in the third direction D3 across the center plane C (the first fins 31 formed at the same position in the second direction D2) are connected to each other at the center plane C and are integrated. Note that the first fins 31 adjacent to each other in the third direction D3 (the first fins 31 formed at the same position in the second direction D2) may be formed separately or may be spaced apart in the third direction D3.

[0027] 3 to 5, the first fins 31 have a uniform height H in the first direction D1 that extends in the flow direction Df. That is, the height H of the first fins 31 in the first direction D1 is constant at all positions in the flow direction Df.

[0028] The first fin 31 has a plurality of slits 33 formed at intervals in the flow direction Df. The plurality of slits 33 are formed at equal intervals in the flow direction Df. When viewed from the second direction D2, the slits 33 are formed in a triangular shape that tapers toward the base plate 11 in the first direction D1. That is, the length L3 of the slits 33 in the flow direction Df gradually decreases toward the base plate 11 in the first direction D1. The slits 33 are formed across the entire area in the first direction D1, from the edge of the first fin 31 opposite the bottom surface 17a in the first direction D1 to the bottom surface 17a. Note that the slits 33 do not necessarily have to extend to the bottom surface 17a. The slits 33 may be formed all at once when the fin 30 is formed by casting, or may be formed by cutting out the fin 30 after it is formed. The slits 33 do not necessarily have to be formed at equal intervals in the flow direction Df. The shape of the slits 33 can be changed as appropriate. The slit 33 may be formed in a rectangular shape extending in the first direction D1 when viewed from the second direction D2.

[0029] The first fin 31 is divided into a plurality of small pieces 31a in the flow direction Df by a plurality of slits 33. The small pieces 31a are formed in a trapezoidal shape. The length of the small pieces 31a in the flow direction Df narrows as they move away from the bottom surface 17a in the first direction D1. The length L4 in the flow direction Df of the edge of each small piece 31a on the bottom surface 17a side is the same for all of the small pieces 31a. Furthermore, the length L4 in the flow direction Df of each small piece 31a is greater than the length L3 of the slits 33 in the flow direction Df.

[0030] (Second fin) The second fins 32 are arranged between adjacent first fins 31. One second fin 32 is arranged in each gap between adjacent first fins 31. Note that the second fins 32 adjacent to each other in the third direction D3 across the center plane C (the second fins 32 formed at the same position in the second direction D2) are in contact with each other at the center plane C. Note that the second fins 32 adjacent to each other in the third direction D3 (the second fins 32 formed at the same position in the second direction D2) may be spaced apart in the third direction D3 or may be formed integrally.

[0031] The height H in the first direction D1 of the second fin 32 on the upstream side Dfu is higher than the height H in the first direction D1 of the second fin 32 on the downstream side Dfd. In other words, the height H in the first direction D1 of the second fin 32 on the downstream side Dfd is lower than the height H in the first direction D1 of the second fin 32 on the upstream side Dfu. In this embodiment, the second fin 32 is formed in a tapered shape such that the height H in the first direction D1 gradually decreases from the upstream side Dfu to the downstream side Dfd as viewed in the second direction D2. In the illustrated example, the second fin 32 is formed in a triangular shape such that the height H in the first direction D1 decreases as viewed in the second direction D2. Therefore, only the end of the second fin 32 on the upstream side Dfu is connected to the upper wall 14 of the casing 10.

[0032] In other words, the second fin 32 has a leading edge 34 formed on the side of the second fin 32 opposite the bottom surface 17a in the first direction D1, and this leading edge 34 is formed in a linear shape that extends in the flow direction Df and slopes toward the bottom surface 17a in the first direction D1 from the upstream side Dfu toward the downstream side Dfd. The end of the second fin 32 on the downstream side Dfd is located on the bottom surface 17a.

[0033] (Action and effect) The following describes the effects of the cold plate 1 of this embodiment. The refrigerant R supplied into the casing 10 through the supply holes 15 collides with the flow path wall 20 and splits into two directions. The refrigerant R then flows along the second side wall 13b and enters each flow path 6 between the fins 30. The refrigerant R flows from the second side wall 13b toward the center plane C. As the refrigerant R flows through the flow paths 6, heat is transferred from the heating element 3 to the refrigerant R. The fins 30 increase the heat transfer area of ​​the cold plate 1, improving heat transfer from the heating element 3 to the refrigerant R. The refrigerant R receives heat from the heating element 3 and boils. At this time, the heat of vaporization of the refrigerant R is removed from the heating element 3, cooling the heating element 3. The vaporized refrigerant R is discharged outside the casing 10 through the outlet. The refrigerant R then circulates through piping (not shown), passes through a condenser, and is again supplied into the casing 10 through the supply holes 15. The coolant R may be circulated only by natural convection caused by the heat of the heating element 3, or the coolant R may be pressure-fed by providing a pump or the like.

[0034] In this embodiment, the cold plate 1 includes a casing 10 and a plurality of fins 30. The casing 10 is disposed adjacent to the heat generating element 3 in a first direction D1 and is attached to the outer surface 3a of the heat generating element 3. A refrigerant R flows through the casing 10. The casing 10 removes heat from the heat generating element 3 by boiling the refrigerant R flowing through the casing 10. The plurality of fins 30 are disposed at intervals in a second direction D2 intersecting the first direction D1 within the casing 10. The fins 30 protrude in the first direction D1 from a bottom surface 17a of the inner surface 17 of the casing 10 that is aligned with the outer surface 3a, and extend in a third direction D3 intersecting both the first direction D1 and the second direction D2. The plurality of fins 30 form flow paths 6 between adjacent fins 30, through which the refrigerant R can flow. The multiple fins 30 include multiple first fins 31 extending from the upstream end 6a to the downstream end 6b of the flow path 6, and multiple second fins 32 arranged between adjacent first fins 31. The height H in the first direction D1 of the second fins 32 on the upstream side Dfu of the flow path 6 in the flow direction Df is greater than the height H in the first direction D1 of the second fins 32 on the downstream side Dfd of the flow direction Df.

[0035] As shown in FIGS. 6 and 7 , bubbles 50 are generated in the cold plate 1 as the refrigerant R boils. The bubbles 50 are flattened by the fins 30. The flat bubbles 50 have a liquid film region 51 with good heat transfer performance and a dryout region 52 with poor heat transfer performance. The volume of the bubbles 50 decreases toward the upstream side Dfu and increases toward the downstream side Dfd. The volume of the bubbles 50 decreases toward the base (lower side) of the fin 30, which is closer to the heat generating element 3 in the first direction D1 (vertical direction), and increases toward the tip (upper side) of the fin 30, which is farther from the heat generating element 3 in the first direction D1 (vertical direction). When the volume of the bubbles 50 increases in the narrow flow path 6, the bubbles 50 obstruct the flow of the refrigerant R. Furthermore, the dryout region 52 increases, which may result in a deterioration in heat transfer performance and a decrease in cooling performance.

[0036] In this embodiment, the first fins 31 and the second fins 32 are arranged alternately, and the height H of the second fins 32 on the upstream side Dfu in the flow direction Df of the flow path 6 is greater than the height H of the second fins 32 on the downstream side Dfd in the flow direction Df. This allows the gaps (flow paths 6) between the fins 30 in the upper part of the casing 10 to become larger as they move further away from the downstream side Dfd and the heating element 3. Therefore, as the volume of the bubbles 50 increases, the bubbles 50 are more likely to flow upward toward the downstream side Dfd, thereby suppressing backflow and unstable flow of the refrigerant R. Furthermore, in the narrow gaps between adjacent fins 30, the dryout region 52 with poor heat transfer performance within the air bubble 50 gradually becomes larger toward the downstream side Dfd. According to this embodiment, the air bubble 50 is more likely to flow out of the narrow gaps between adjacent fins 30 into a wider space above the second fin 32 as it moves toward the downstream side Dfd. When the air bubble 50 flows out into the wider space, the dryout region 52 shrinks. In this way, backflow and unstable flow of the refrigerant R are suppressed, and the dry-out region 52 of the bubbles 50 on the downstream side Dfd can be reduced, thereby suppressing deterioration of heat transfer performance and improving cooling performance. Furthermore, the improved cooling performance reduces the energy required to cool the heat-generating body. Furthermore, since there is no need to change the volume of the casing 10, the cold plate 1 can be prevented from becoming large.

[0037] In this embodiment, the second fin 32 has a leading edge 34 formed on the opposite side of the bottom surface 17a in the first direction D1 and extending in the flow direction Df. The leading edge 34 is inclined in the first direction D1 so as to approach the bottom surface 17a from the upstream side Dfu toward the downstream side Dfd.

[0038] According to this embodiment, the flow path area between the fins 30 gradually increases from the upstream side Dfu to the downstream side Dfd. This reduces the increase in pressure loss associated with the volumetric flow rate of the refrigerant R that occurs from the upstream side Dfu to the downstream side Dfd, thereby suppressing the occurrence of unstable flow accompanied by a sudden change in the flow rate of the refrigerant R and an increase in pressure loss. In this embodiment, the leading edge 34 is formed in a straight line, but this is not limiting. The leading edge 34 may be formed in a curved line such that the height H of the second fin 32 in the first direction D1 decreases. Even in this case, the cold plate 1 can achieve the same advantageous effects.

[0039] Second Embodiment A cold plate 201 according to a second embodiment of the present disclosure will be described below with reference to Figures 8 to 10. Among the configurations of the second embodiment, configurations common to the above-described embodiment will be given the same names and symbols, and descriptions thereof will be omitted as appropriate.

[0040] As shown in FIGS. 8 to 10 , in this embodiment, the multiple fins 230 include multiple first fins 31 and multiple second fins 232. The second fins 232 extend in the flow direction Df from the upstream end 6a of the flow channel 6, but the length L2 of the second fins 232 in the flow direction Df is shorter than the length L1 of the first fins 31 in the flow direction Df. The second fins 232 are formed on the opposite side of the bottom surface 17a in the first direction D1 and have leading edges 234 extending in the flow direction Df. The leading edges 234 are formed in a stepped shape that gradually approaches the bottom surface 17a in the first direction D1 from the upstream side Dfu to the downstream side Dfd. That is, the leading edge 234 has multiple step surfaces 235 aligned in the flow direction Df. Each step surface 235 extends in the flow direction Df parallel to the bottom surface 17a. The multiple step surfaces 235 are located closer to the bottom surface 17a in the first direction D1 from the upstream side Dfu to the downstream side Dfd. The distance in the first direction D1 between adjacent step surfaces 235 in the flow direction Df is all equal. Furthermore, of the multiple step surfaces 235, only the step surface 235 on the most upstream side Dfu is connected to the upper wall 14 of the casing 10.

[0041] (Action and effect) The following describes the effects of the cold plate 201 of this embodiment. The cold plate 201 of this embodiment not only provides the same fluid and thermal effects as the first embodiment described above, but also provides the following effects. In this embodiment, the leading edge 234 is formed in a stepped shape that gradually approaches the bottom surface 17a in the first direction D1 from the upstream side Dfu toward the downstream side Dfd.

[0042] This makes it easy to change the design of the height H of the second fins 232, and allows the second fins 232 to be designed to match the specifications of the cold plate 201, such as the amount of heat generated and the type of refrigerant R.

[0043] <Third embodiment> A cold plate 301 according to a third embodiment of the present disclosure will be described below with reference to Figures 11 to 13. Among the configurations of the third embodiment, configurations common to the above-described embodiments will be given the same names and reference numerals, and descriptions thereof will be omitted as appropriate.

[0044] As shown in FIGS. 11 to 13 , in this embodiment, the multiple fins 330 include multiple first fins 31 and multiple second fins 332. The center 332a of the second fin 332 in the flow direction Df is located on the upstream side Dfu, and the length L2 of the second fin 332 in the flow direction Df is shorter than the length L1 of the first fin 31 in the flow direction Df. In this embodiment, the end of the upstream side Dfu of the second fin 332 is located at the upstream end 6a of the flow channel 6, and the end of the downstream side Dfd of the second fin 332 is located at a central position in the flow direction Df of the flow channel 6. The length L2 of the second fin 332 in the flow direction Df is half the length L1 of the first fin 31. Note that the position of the end of the upstream side Dfu of the second fin 332 can be changed as appropriate. The end of the upstream side Dfu of the second fin 332 may be located downstream Dfd of the upstream end 6a of the flow channel 6.

[0045] In this embodiment, similar to the first fin 31, the second fin 332 has a height H in the first direction D1 that extends uniformly in the flow direction Df. That is, the height H of the second fin 332 in the first direction D1 is constant at all positions in the flow direction Df. The entire area of ​​the second fin 332 in the flow direction Df is connected to the upper wall 14 of the casing 10. Similarly to the first fin 31, the second fin 332 has a plurality of slits 33 formed at intervals in the flow direction Df. The slits 33 of the second fin 332 are formed at the same positions in the flow direction Df as the slits 33 of the first fin 31. That is, the slits 33 of the second fin 332 overlap with the slits 33 of the first fin 31 in the second direction D2.

[0046] (Action and effect) The following describes the effects of the cold plate 301 of this embodiment. The cold plate 301 of this embodiment not only provides the same fluid and thermal effects as the first embodiment described above, but also provides the following effects. In this embodiment, the center 332a of the second fin 332 in the flow direction Df is located on the upstream side Dfu, and the length of the second fin 332 in the flow direction Df is shorter than the length of the first fin 31 in the flow direction Df.

[0047] This allows the cooling performance to be improved as described above simply by shortening the length of the second fin 332, while the second fin 332 and the first fin 31 can be designed to have similar shapes, thereby improving the manufacturing efficiency of the fin 330.

[0048] <Fourth embodiment> A cold plate 401 according to a fourth embodiment of the present disclosure will be described below with reference to Figures 14 to 16. Among the configurations of the fourth embodiment, configurations common to the above-described embodiments will be given the same names and reference numerals, and descriptions thereof will be omitted as appropriate.

[0049] As shown in FIGS. 14 to 16, the cold plate 401 has a plurality of fins 430. In this embodiment, the cold plate 401 includes a casing 10 and a plurality of fins 430. The plurality of fins 430 are all formed to have the same shape. The plurality of fins 430 form flow paths 6 between adjacent fins 430, through which the refrigerant R can flow. The height H in the first direction D1 of the fins 430 on the upstream side Dfu in the flow direction Df of the flow path 6 is higher than the height H in the first direction D1 of the fins 430 on the downstream side Dfd in the flow direction Df. In other words, the height H in the first direction D1 of the fins 430 on the downstream side Dfd is lower than the height H in the first direction D1 of the fins 430 on the upstream side Dfu.

[0050] In this embodiment, the leading edge 434 of the fin 430 has a parallel portion 434a on the upstream side Dfu and an inclined portion 434b on the downstream side Dfd. The parallel portion 434a extends parallel to the bottom surface 17a. The inclined portion 434b extends from the downstream end 434c of the parallel portion 434a further toward the downstream side Dfd. The inclined portion 434b inclines toward the bottom surface 17a as it extends toward the downstream side Dfd. The end of the inclined portion 434b on the downstream side Dfd is located on the bottom surface 17a. Of the fin 430, only the parallel portion 434a is connected to the upper wall 14 of the casing 10.

[0051] (Action and effect) The following describes the effects of the cold plate 401 of this embodiment. In this embodiment, the cold plate 401 includes a casing 10 and a plurality of fins 430. The fins 430 are arranged in the casing 10 at intervals in a second direction D2 intersecting with the first direction D1. The fins 430 protrude in the first direction D1 from a bottom surface 17a of the inner surface 17 of the casing 10, which is aligned with the outer surface 3a, and extend in a third direction D3 intersecting with both the first direction D1 and the second direction D2. The fins 430 form flow paths 6 between adjacent fins 430 through which the refrigerant R can flow. The height H of the fins 430 in the first direction D1 at the upstream side Dfu in the flow direction Df of the flow path 6 is greater than the height H of the fins 430 in the first direction D1 at the downstream side Dfd in the flow direction Df.

[0052] In this embodiment, the height H of the fins 430 on the upstream side Dfu in the flow direction Df of the flow path 6 is greater than the height H of the fins 430 on the downstream side Dfd in the flow direction Df. This allows the gaps (flow path 6) between the fins 430 in the upper part of the casing 10 to be enlarged toward the downstream side Dfd. Therefore, as the volume of the bubbles 50 increases, the bubbles 50 are more likely to flow toward the downstream side Dfd and upward, thereby suppressing backflow and unstable flow of the refrigerant R. Furthermore, in the narrow gaps between adjacent fins 430, the dryout region 52 with poor heat transfer performance within the air bubble 50 gradually increases toward the downstream side Dfd. According to this embodiment, the air bubble 50 is more likely to flow out of the narrow gaps between adjacent fins 430 into a wider space above the fins 430 as it moves toward the downstream side Dfd. When the air bubble 50 flows out into the wider space, the dryout region 52 shrinks. In this way, backflow and unstable flow of the refrigerant R are suppressed, and the dry-out region 52 of the bubbles 50 on the downstream side Dfd can be reduced, thereby suppressing deterioration of heat transfer performance and improving cooling performance. Furthermore, the improved cooling performance reduces the energy required to cool the heat-generating body. Furthermore, since there is no need to change the volume of the casing 10, the cold plate 401 can be prevented from becoming large.

[0053] In this embodiment, the downstream end of the inclined portion 434b of the leading edge 434 is located on the bottom surface 17a, but this is not limited to this. The shape of the fin 430 can be changed as appropriate. For example, as shown in FIG. 17, the downstream end of the inclined portion 434b of the leading edge 434 may be spaced apart from the bottom surface 17a in the first direction D1. (The downstream end of the inclined portion 434b may be located above the bottom surface 17a.) In addition, the position of the boundary between the parallel portion 434a and the inclined portion 434b can be changed as appropriate.

[0054] In addition, in this embodiment, the plurality of fins 430 are all formed in the same shape, but this is not limiting, and some of the fins 430 may be formed in different shapes.

[0055] (Other embodiments) The above describes in detail the embodiments of the present disclosure with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present disclosure.

[0056] In the above embodiment, the cold plates 1, 201, 301, and 401 are arranged to extend horizontally, but this is not limiting. The orientation of the cold plates 1, 201, 301, and 401 can be changed as appropriate depending on the shape and orientation of the heating element 3. For example, the cold plates 1, 201, 301, and 401 may be arranged at an angle relative to the horizontal.

[0057] In the first to third embodiments, the first fins 31 and the second fins 32, 232, 332 are alternately arranged one by one in the second direction D2, but this is not limiting. For example, a plurality of second fins 32, 232, 332 may be provided between adjacent first fins 31, or a plurality of first fins 31 may be provided between adjacent second fins 32, 232, 332.

[0058] In the first to third embodiments, the slits 33 are formed in the first fin 31 and the second fin 32, 232, 332, but this is not limitative. The slits 33 do not have to be formed in the first fin 31 and the second fin 32, 232, 332. In addition, in the fourth embodiment, the slits 33 are not formed in the fins 430, but this is not limiting. In the fourth embodiment, the slits 33 may be formed in the fins 430, similar to the first to third embodiments.

[0059] <Additional Notes> The cold plates 1, 201, 301, and 401 described in the respective embodiments can be understood, for example, as follows.

[0060] (1) A cold plate 1, 201, 301 according to a first aspect includes a casing 10 that is disposed adjacent to a heat generating element 3 in a first direction D1 and is attached to an outer surface 3a of the heat generating element 3, and that removes heat from the heat generating element 3 by boiling a refrigerant R flowing therethrough, and a plurality of fins 30, 230, 330 that are disposed within the casing 10 at intervals in a second direction D2 that intersects with the first direction D1, and the fins 30, 230, 330 protrude in the first direction D1 from a bottom surface 17a of an inner surface 17 of the casing 10 that is along the outer surface 3a, and are arranged in a direction that intersects both the first direction D1 and the second direction D2. The fins 30, 230, 330 form a flow path 6 between adjacent fins 30, 230, 330 through which the refrigerant R can flow, and the fins 30, 230, 330 include a plurality of first fins 31 extending from an upstream end 6a to a downstream end 6b of the flow path 6 and a plurality of second fins 32, 232, 332 arranged between adjacent first fins 31, and a height H in the first direction D1 of the second fins 32, 232, 332 on the upstream side Dfu of the flow path 6 in the flow direction Df is greater than a height H in the first direction D1 of the second fins 32, 232, 332 on the downstream side Dfd of the flow direction Df.

[0061] In this embodiment, the first fins 31 and the second fins 32, 232, 332 are arranged alternately, and the height H of the second fins 32, 232, 332 on the upstream side Dfu in the flow direction Df of the flow path 6 is greater than the height H of the second fins 32, 232, 332 on the downstream side Dfd in the flow direction Df. This allows the gaps (flow path 6) between the fins 30, 230, 330 to expand toward the downstream side Dfd. Therefore, as the volume of the bubbles 50 increases, the bubbles 50 are more likely to flow toward the downstream side Dfd, suppressing backflow and unstable flow of the refrigerant R. Furthermore, in the narrow gaps between adjacent fins 30, 230, 330, the dryout region 52 with poor heat transfer performance within the air bubble 50 gradually increases toward the downstream side Dfd. According to this embodiment, the air bubble 50 is more likely to flow out of the narrow gaps between adjacent fins 30, 230, 330 into a wider space as it moves toward the downstream side Dfd. When the air bubble 50 flows out into the wider space, the dryout region 52 shrinks. In this way, backflow and unstable flow of the refrigerant R can be suppressed, and the dry-out region 52 of the bubbles 50 on the downstream side Dfd can be reduced, thereby suppressing deterioration of heat transfer performance and improving cooling performance. Furthermore, since there is no need to change the volume of the casing 10, the cold plates 1, 201, 301 can be prevented from becoming larger.

[0062] (2) A second aspect of the cold plate 1 is the cold plate 1 of (1), wherein the second fin 232 has a leading edge 34 formed on the opposite side of the bottom surface 17a in the first direction D1 and extending in the flow direction Df, and the leading edge 34 may be inclined so as to approach the bottom surface 17a in the first direction D1 as it moves from the upstream side Dfu to the downstream side Dfd.

[0063] According to this aspect, the flow path area between the fins 30 gradually increases from the upstream side Dfu to the downstream side Dfd. This reduces the increase in pressure loss associated with the volumetric flow rate of the refrigerant R that occurs from the upstream side Dfu to the downstream side Dfd, thereby suppressing the occurrence of unstable flow accompanied by abrupt changes in the flow rate of the refrigerant R and an increase in pressure loss.

[0064] (3) A third aspect of the cold plate 201 is the cold plate 201 of (1), wherein the second fin 232 has a leading edge 234 formed on the opposite side of the bottom surface 17a in the first direction D1 and extending in the flow direction Df, and the leading edge 234 may be formed in a stepped shape that gradually approaches the bottom surface 17a in the first direction D1 as it moves from the upstream side Dfu to the downstream side Dfd.

[0065] This makes it easy to change the design of the height H of the second fins 232, and allows the second fins 232 to be designed to match the specifications of the cold plate 201, such as the amount of heat generated and the type of refrigerant R.

[0066] (4) The cold plate 301 of the fourth aspect is the cold plate 301 of (1), wherein the center 332a of the flow direction Df of the second fin 332 is located on the upstream side Dfu, and the length of the flow direction Df of the second fin 332 may be shorter than the length of the flow direction Df of the first fin 31.

[0067] This allows the cooling performance to be improved as described above simply by shortening the length of the second fin 332, while the second fin 332 and the first fin 31 can be designed to have similar shapes, thereby improving the manufacturing efficiency of the fin 330.

[0068] (5) A cold plate 401 according to a fifth aspect includes a casing 10 that is disposed adjacent to a heat generating element 3 in a first direction D1 and is attached to an outer surface 3a of the heat generating element 3, and that removes heat from the heat generating element 3 by boiling a refrigerant R flowing therethrough, and a plurality of fins 430 that are disposed in the casing 10 at intervals in a second direction D2 that intersects with the first direction D1, and the fins 430 are disposed on an inner surface 17 of the casing 10 that is adjacent to the outer surface 3a. The fins 430 protrude in the first direction D1 from a bottom surface 17a along the axial direction of the fin 430 and extend in a direction intersecting both the first direction D1 and the second direction D2, and the fins 430 form a flow path 6 between adjacent fins 430 through which the refrigerant R can flow, and the height H in the first direction D1 of the fin 430 at the upstream side Dfu of the flow direction Df of the flow path 6 is higher than the height H in the first direction D1 of the fin 430 at the downstream side Dfd of the flow direction Df.

[0069] In this embodiment, the height H of the fins 430 on the upstream side Dfu in the flow direction Df of the flow path 6 is greater than the height H of the fins 430 on the downstream side Dfd in the flow direction Df. This allows the gaps (flow path 6) between the fins 430 to be enlarged toward the downstream side Dfd. Therefore, as the volume of the bubbles 50 increases, the bubbles 50 are more likely to flow toward the downstream side Dfd, and backflow and unstable flow of the refrigerant R are suppressed. Furthermore, in the narrow gaps between adjacent fins 430, the dryout region 52 with poor heat transfer performance within the air bubble 50 gradually increases toward the downstream side Dfd. According to this embodiment, the air bubble 50 is more likely to flow out of the narrow gaps between adjacent fins 430 into a wider space toward the downstream side Dfd. When the air bubble 50 flows out into the wider space, the dryout region 52 shrinks. In this way, backflow and unstable flow of the refrigerant R can be suppressed, and the dry-out region 52 of the bubbles 50 on the downstream side Dfd can be reduced, thereby suppressing deterioration of heat transfer performance and improving cooling performance. Furthermore, since there is no need to change the volume of the casing 10, the cold plate 401 can be prevented from becoming large. [Explanation of symbols]

[0070] 1...cold plate, 2...substrate, 3...heating element, 3a...outer surface, 4...supply port, 5...exhaust port, 6...flow path, 6a...upstream end, 6b...downstream end, 10...casing, 11...base plate, 12...cover, 13...side wall, 13a...first side wall, 13b...second side wall, 14...upper wall, 15...supply hole, 16...exhaust hole, 17...inner surface, 17a...bottom surface, 20...flow path wall, 30...fin, 31...first fin, 31a...small piece, 32...second fin, 33...slit, 34...tip edge, 50...air bubble, 51...liquid film region, 52...dry-out region, 201...cold plate Cold plate, 230...fin, 232...second fin, 234...leading edge, 235...step surface, 301...cold plate, 330...fin, 332...second fin, 332a...center, 401...cold plate, 430...fin, 434...leading edge, 434a...parallel portion, 434b...inclined portion, 434c...downstream end, C...center surface, D1...first direction, D2...second direction, D3...third direction, Df...flow direction, Dfu...upstream side, Dfd...downstream side, H...height, L1...length, L2...length, L3...length, L4...length, R...refrigerant, W1...width, W2...width

Claims

1. a casing that is disposed adjacent to the heat generating element in the first direction and is attached to an outer surface of the heat generating element, and that boils a refrigerant flowing inside the casing to remove heat from the heat generating element; a plurality of fins disposed in the casing at intervals in a second direction intersecting the first direction; Equipped with the fins protrude in the first direction from a bottom surface of the inner surface of the casing that is along the outer surface, and extend in a direction intersecting both the first direction and the second direction; The plurality of fins form a flow path between adjacent fins through which the coolant can flow, The plurality of fins include: a plurality of first fins extending from an upstream end to a downstream end of the flow channel; a plurality of second fins disposed between adjacent first fins; Including, a height in the first direction of the second fin on an upstream side of the flow path in the flow direction is greater than a height in the first direction of the second fin on a downstream side of the flow path in the flow direction; Cold plate.

2. the second fin is formed on the opposite side of the bottom surface in the first direction and has a tip edge extending in the flow direction, the leading edge is inclined so as to approach the bottom surface side in the first direction from the upstream side toward the downstream side; The cold plate of claim 1 .

3. the second fin is formed on the opposite side of the bottom surface in the first direction and has a tip edge extending in the flow direction, The tip edge is formed in a stepped shape that gradually approaches the bottom surface side in the first direction from the upstream side to the downstream side. The cold plate of claim 1 .

4. a center of the second fin in the flow direction is located on the upstream side; The length of the second fin in the flow direction is shorter than the length of the first fin in the flow direction. The cold plate of claim 1 .

5. a casing that is disposed adjacent to the heat generating element in the first direction and is attached to an outer surface of the heat generating element, and that boils a refrigerant flowing inside the casing to remove heat from the heat generating element; a plurality of fins disposed in the casing at intervals in a second direction intersecting the first direction; Equipped with the fins protrude in the first direction from a bottom surface of the inner surface of the casing that is along the outer surface, and extend in a direction intersecting both the first direction and the second direction; The plurality of fins form a flow path between adjacent fins through which the coolant can flow, a height in the first direction of the fins on an upstream side of the flow path in the flow direction is greater than a height in the first direction of the fins on a downstream side of the flow path in the flow direction; Cold plate.

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