Pulsating heat pipe heat sink

Abstract

The invention relates to a pulsating heat pipe heat sink (10; 10a to 10g) comprising: a housing (12) in which at least one channel (14) for conveying an evaporable cooling medium is disposed; an evaporator region (20; 20a to 20g) in which at least one component to be cooled can be disposed; a condenser region (22; 22a to 22g) which is spaced from the evaporator region (20; 20a to 20g), wherein the at least one channel (14) extends at least between the evaporator region (20; 20a to 20g) and the condenser region (22; 22a to 22g) and has a meandering design; first channel portions (26a to 26l) in the evaporator region (20; 20a to 20g) and second channel portions (30a to 30l) in the condenser region (22; 22a to 22g); and first deflection regions (28) for connecting two first channel portions (26a to 26l) on the side of the evaporator region (20; 20a to 20g) farther from the condenser region (22; 22a to 22g) and second deflection regions (32) for connecting two second channel portions (30a to 30l) on the side of the condenser region (22; 22a to 22g) farther from the evaporator region (20; 20a to 20g).

Description

[0001] R.408920

[0002] Description

[0003] Technical field

[0004] The invention relates to a pulsating heat pipe heat sink, hereinafter referred to simply as heat pipe heat sink, which is characterized by particularly good heat transfer into a cooling medium in an evaporator area or by particularly good heat transfer of the cooling medium in a condenser area.

[0005] State of the art

[0006] From EP 3 754 281 B1, a heat pipe cooling element with the features of the preamble of claim 1 is known. The known heat pipe cooling element, which is manufactured using an additive process, is characterized in a condenser section or in an evaporator section by the fact that short, helical or frustoconical sections are provided in the channel formed there for the cooling medium, which connect directly to one another in the manner of chain links. This is intended to achieve a preferred flow direction of the cooling medium in the channel or to promote heat transfer.

[0007] From CN 207124843 U, another heat pipe cooling element with the features of the preamble of claim 1 is known, which has sections in its channel for the cooling medium in an evaporator and / or condenser area, the cross-sections of which either change continuously or are enlarged or reduced compared to other sections. R.408920

[0008] - 2 -

[0009] Disclosure of the invention

[0010] The (pulsating) heat pipe heat sink according to the invention with the features of claim 1 has the advantage that it enables particularly good heat transfer in the evaporator area and / or condenser area.

[0011] The invention is based on the idea of ​​designing the channel sections in the evaporator and / or condenser areas with a non-linear or non-straight-line configuration, resulting in a longer flow path or increased flow resistance for the cooling medium, in order to improve heat transfer. In particular, this allows for the generation of larger (vapor) bubbles per unit area of ​​the heat sink or channel in the evaporator area. Furthermore, by influencing the pressure behavior for a preferred flow direction of the cooling medium, heat transfer from the evaporator area towards the condenser area and vice versa is also to be promoted.

[0012] In light of the above explanations, a pulsating heat pipe heat sink according to the invention, having the features of claim 1, therefore comprises a housing in which at least one channel for guiding a vaporizable cooling medium is arranged. Furthermore, an evaporator area for arranging at least one component to be cooled and a condenser area at a distance from the evaporator area are provided, wherein the at least one channel extends at least between the evaporator area and the condenser area and is designed to be at least substantially meandering.First channel sections are provided in the evaporator area and second channel sections in the condenser area, with first deflection sections for connecting two first channel sections on the side of the evaporator area facing away from the condenser area and second deflection sections for connecting two second channel sections on the side of the condenser area facing away from the evaporator area. Furthermore, means for increasing heat transfer from the housing to the cooling medium or from the cooling medium to the housing are provided in the condenser and / or evaporator area. According to the invention, the means comprise at least one corrugated section in the area of ​​at least one first and / or second channel section. R.408920.

[0013] - 3 -

[0014] Advantageous further developments of the heat pipe cooling body according to the invention are listed in the dependent claims.

[0015] It is particularly preferred if the means are designed to create a preferred flow direction of the cooling medium in the at least one channel. Such a preferred flow direction of the cooling medium can be achieved by breaking the symmetry of the arrangement and / or design of the corrugated sections.

[0016] In a preferred design embodiment, it is provided that several, preferably periodically repeating, wave-shaped sections are provided in the at least one first and / or second channel section.

[0017] In order to enable a particularly compact arrangement of the individual first and / or second channel sections, it is also preferably provided that wave-shaped sections are formed on at least two immediately adjacent first and / or second channel sections, and that the wave-shaped sections are either identical, wherein the wave-shaped sections are arranged parallel to each other, i.e. without offset in the longitudinal direction in the first and / or second channel sections, or that the wave-shaped sections are formed on mutually facing sides of the first and / or second channel sections, wherein the wave-shaped sections are arranged offset from each other when viewed in the longitudinal direction of the first and / or second channel sections.

[0018] To generate a preferred flow direction of the cooling medium, it can also be provided that a straight section is formed between two corrugated sections in a first and / or second channel section, and / or that at least one first and / or second channel section is straight. In the straight sections, reduced flow resistance for the cooling medium is generated, so that the cooling medium preferentially flows in the direction of these sections. R.408920

[0019] - 4 -

[0020] It may also be provided that the preferred flow direction of the cooling medium is influenced by different distances between the first and / or second channel sections.

[0021] Further influence on heat transfer and / or flow direction of the medium can be achieved by ensuring that the wave-shaped sections in the first and / or second channel sections extend over different lengths of the first and / or second channel sections and / or are arranged offset from each other.

[0022] Further influence on the above-mentioned properties is possible if wave-shaped sections are provided in the first and / or second deflection areas.

[0023] It is also possible to incorporate wave-like structures or microsections in the wall area of ​​the corrugated sections. This further increases the flow resistance or promotes turbulent flow of the cooling medium.

[0024] There are different possibilities regarding the shape of the wave-like sections. In particular, it is intended that the wave-like sections are sinusoidal, zigzag-shaped, or circular segment-shaped.

[0025] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments of the invention and from the drawings.

[0026] Brief description of the drawings

[0027] Fig. 1 to

[0028] Fig. 8 shows longitudinal sections through heat pipe heat sinks with differently designed channels,

[0029] Fig. 9a R.408920

[0030] - 5 - to

[0031] Fig. 9e shows differently shaped forms of wave-like sections of a channel and

[0032] Fig. 10 shows a section of a channel which is provided with wave-shaped structures in the area of ​​its wall.

[0033] Embodiments of the invention

[0034] Identical elements or elements with the same function are provided with the same reference numbers in the figures.

[0035] The pulsating heat pipe heat sink 10 shown in Fig. 1, hereinafter referred to simply as heat pipe heat sink 10, serves to cool at least one heat-emitting component (not shown) that dissipates heat during operation. This component can be, for example, a power IC, an electromechanical assembly, or something else. The heat pipe heat sink 10 can, for example, be arranged in the area of ​​a control unit (not shown).

[0036] The heat pipe heat sink 10 has a housing 12 (not shown in detail), which, for example, is cuboid in shape overall. In particular, the housing 12 is made up of multiple parts and has at least one channel 14 in its interior for guiding a vaporizable cooling medium (not shown). The cooling medium can be filled into the at least one channel 14 via a filling channel 16 located at the edge of the housing 12, the filling channel 16 being closable (not shown) to prevent unintentional leakage of the cooling medium.

[0037] The heat pipe heat sink 10 has at least one evaporator area 20, characterized by a rectangular boundary 19 in Fig. 1, and a condenser area 22 arranged at a lateral distance from the evaporator area 20 in the plane of Fig. 1. In the evaporator area 20, the at least one component is thermally connected to the housing 12 in a plane parallel to the plane of Fig. 1, for example by a thermally conductive adhesive. R.408920

[0038] - 6 - In addition, for the capacitor area 22, it may optionally be provided that an additional heat sink in the form of cooling fins or similar is connected to the housing 12. The additional heat sink can be designed as a separate component, or it can form a monolithic unit together with the housing 12.

[0039] The operating principle of the heat pipe cooling element 10 described so far is known per se and is therefore only briefly summarized below: During operation of the at least one component, it transfers heat via the housing 12 to the cooling medium located in the evaporator area 20. Due to the heating, the cooling medium evaporates, forming vapor bubbles, and, as a result of pressure pulsations, enters the condenser area 22, where, due to the cooler external environment compared to the evaporator area 20 (because, among other things, no component to be cooled is located in the condenser area 22) and / or the aforementioned additional cooling element, it condenses again and flows back into the evaporator area 20.

[0040] Channel 14 has several first channel sections 26a to 26j, at least on the side facing the evaporator section 20, which are arranged essentially parallel to each other. The first channel sections 26a to 26j, arranged directly adjacent to each other, are connected to one another on the side of the evaporator section 20 facing away from the condenser section 22 by means of first deflection sections 28. The two outer, oppositely arranged first channel sections 26a and 26j are connected to the filling channel 16 via a connecting channel 27 on the side facing away from the first deflection sections 28.

[0041] In the capacitor section 22, channel 14 has several second, parallel channel sections 30a to 30j, which are designed as extensions of the first channel sections 26a and 26j. Two adjacent second channel sections 30b to 30i are connected to each other via second deflection sections 32. The two outer second channel sections 30a and 30i terminate in the connecting channel 27. R.408920

[0042] - 7 -

[0043] The arrangement of the first channel sections 26a to 26j, the second channel sections 30a to 30j, and the deflection areas 28, 32 described above results in a meandering shape for the channel 14. It should be added that in the illustrated embodiment, the channel 14 is designed as an endless, or closed, channel 14. However, it is also possible to design the channel 14 as a channel 14 closed at both ends, as is known from the prior art. In this case, for example, the two second channel sections 30a and 30j are closed on the side facing away from the first channel sections 26a and 26j.

[0044] While the second channel sections 30a to 30j of the heat pipe cooling body 10 are designed to be straight, it is provided that at least some of the first channel sections 26a to 26j, preferably at least some of the first channel sections 26a to 26j arranged in the evaporator area 20, are equipped with means 34 to increase the flow resistance for the cooling medium.

[0045] The means 34 consist of the formation of non-linear, wave-shaped sections 36. For example, the wave-shaped sections 36 are each sinusoidal with the same wavelength and amplitude and, in the first channel sections 26b, 26c, 26g to 26j, each comprise three periodically successive wave-shaped sections 36. In the first channel section 26f, two sections 36 are provided with a straight section 37 arranged between the two sections 36. The first channel section 26e comprises only one wave-shaped section 36, which is arranged between the two sections 36 of the first channel section 26f on the side facing the first channel section 26f.

[0046] The means 34 or sections 36 influence the vapor bubble formation of the cooling medium in the evaporator area 20, which in turn influences the pressure gradient of the cooling medium in the channel 14, leading to a preferred direction of flow of the cooling medium in the channel 14.

[0047] The heat pipe cooling element 10a shown in Fig. 2 with the first channel sections 26a to 26j and the second channel sections 30a to 30j has R.408920

[0048] - 8 - On the side facing the evaporator area 20a, trapezoidal sections 36a with rounded corners form the means 34. The sections 36a, preferably arranged parallel to each other, are exemplified in the area of ​​the first channel sections 26b to 26h, while the first channel sections 26a, 26i, and 26j are each straight. The width b of the sections 36a can vary, as can their height and their distances from each other. The number of sections 36a in the first channel sections 26a to 26j can also vary. Furthermore, the distances a between individual first channel sections 26a to 26j can also vary.The second channel sections 30a to 30j may be enlarged or reduced in size, as shown between the first channel sections 26a and 26b and between the first channel sections 26d and 26e, in order to influence the formation of vapor bubbles and thus the pressure gradient and the preferred direction of flow of the cooling medium.

[0049] In the heat pipe cooling element 10b shown in Fig. 3, with the first channel sections 26a to 26I, the evaporator section 20b features wave-shaped sections 36 in the first channel sections 26b, 26c, 26e, 26g, and 26h. In contrast, the first channel sections 26d and 26f are straight. The limited number of sections 36 in the evaporator section 20b allows for control of the preferred flow direction of the cooling medium. Furthermore, the heat input into the cooling medium and the temperature distribution in the evaporator section 20a can be precisely controlled.

[0050] In the heat pipe heat sink 10c shown in Fig. 4, with first channel sections 26a to 26j and second channel sections 30a to 30j, it is provided that only in the condenser area 22c are wave-shaped sections 36, which in the illustrated example are composed of semicircular sections. The sections 36 are provided by way of example on the second channel sections 30b to 30i. In contrast, the first channel sections 26a to 26j on the evaporator side are all straight. Such an arrangement of wave-shaped sections 40 in the condenser area 22c is particularly advantageous if the condenser area 22c has only a relatively small area, which is described by R.408920.

[0051] - 9 - the dashed outline 42 should be clarified. This allows the heat to be dissipated more effectively by the cooling medium.

[0052] In modification of the embodiments described so far, it is of course also possible that the heat pipe cooling sinks 10, 10a, 10b and 10c have means 34 or sections 36, 36a in both the evaporator area 20, 20a to 20c and the condenser area 22, 22a to 22c.

[0053] Such a case is illustrated in the heat pipe heat sink 10d according to Fig. 5. The heat pipe heat sink 10d, with its evaporator section 20d and condenser section 22d, represents a combination similar to the heat pipe heat sink 10b of Fig. 3 in its evaporator section 20b and similar to the heat pipe heat sink 10c of Fig. 4 in its condenser section 22c. This means that (wave-shaped) sections 36 are present in both the evaporator section 20d and the condenser section 22d.

[0054] The heat pipe cooling element 10e according to Fig. 6 has, in its evaporator section 20e, wave-shaped sections 44 of varying lengths L and positions within the first channel sections 26b to 26h. Compared to sections 36 and 36a, the sections 44 have a reduced wavelength and amplitude, thus enabling a plurality of sections 44 within the evaporator section 20e. The wave-shaped sections 44 can be oriented either towards the condenser section 22e or towards the side facing away from the condenser section 22e, as also shown in Fig. 6. The number, position, and shape of the sections 44 allow for local adjustment of the bubble formation of the cooling medium within the evaporator section 20e to promote a preferred flow direction of the cooling medium.

[0055] The heat pipe cooling element 10f according to Fig. 7 differs from the heat pipe cooling element 10e according to Fig. 6 essentially in that the first deflection areas 28 are formed by corrugated sections 44. This is particularly advantageous when the first deflection areas 28 are arranged in the evaporator area 20f. R.408920

[0056] - 10 -

[0057] The heat pipe cooling element 10g shown in Fig. 8 is similar in design to the heat pipe cooling element 10e shown in Fig. 6. The heat pipe cooling element 10g has differently shaped, wave-like sections 50 to 52 in its evaporator area 20g. The wave-like sections 50 to 52 can vary in both length and exact shape. They also do not necessarily have to repeat periodically.

[0058] Figures 9a to 9e show differently shaped, wave-like sections 53 to 57. Section 53 in Figure 9a has a sinusoidal shape on the opposite wall regions of the channel 14. Section 54 in Figure 9b consists of semicircular sections with alternating directions of curvature. Section 55 in Figure 9c, like section 53, is also sinusoidal, but the sinusoidal shape is related to the center line 58 of the channel 14. Section 56 in Figure 9d has a zigzag shape, and section 57 in Figure 9e has a zigzag shape with a trapezoidal form.

[0059] Finally, Fig. 10 shows a wave-shaped section 60 which has additional wave-shaped structures 62 on its opposite wall regions. The amplitude and frequency of the structures 62 are lower than those of the section 60. The structures 62 on the two opposite wall regions may also differ from each other. The structures 62 do not refer to low wall roughness resulting from the manufacturing process of the section 60, but rather to increased wall roughness, preferably generated by a separate process step.

[0060] The heat pipe cooling element 10, 10a to 10g described so far can be modified or adapted in various ways without deviating from the inventive concept. For example, the cross-section of the channel 14 in the first and / or second channel sections 26a to 26I, 30a to 30I can also be locally changed to alter the flow resistance for the cooling medium.

Claims

R.408920 - 11 - Claims 1. Pulsating heat pipe heat sink (10; 10a to 10g), comprising a housing (12) in which at least one channel (14) for guiding an evaporable cooling medium is arranged, comprising an evaporator area (20; 20a to 20g) for arranging at least one component to be cooled and a condenser area (22; 22a to 22g) arranged at a distance from the evaporator area (20; 20a to 20g), wherein the at least one channel (14) extends at least between the evaporator area (20; 20a to 20g) and the condenser area (22; 22a to 22g) and is designed in a meandering shape, comprising first channel sections (26a to 26I) in the evaporator area (20; 20a to 20g) and second channel sections (30a to 30I) in the condenser area (22; 22a to 22g), with first Deflection areas (28) for connecting two first channel sections (26a to 26I) on the side of the evaporator area (20; 22g) facing away from the condenser area (22; 22a to 22g).20a to 20g) and second deflection sections (32) for connecting two second channel sections (30a to 30I) on the side of the condenser section (22; 22a to 22g) facing away from the evaporator section (20; 20a to 20g), and with means (34) for increasing heat transfer from the housing (12) to the cooling medium or from the cooling medium to the housing (12) in the condenser section (22; 22a to 22g) and / or in the evaporator section (20; 20a to 20g), characterized in that the means (34) comprise at least one corrugated section (36; 36a; 40; 50 to 57; 60) in the area of ​​at least one first channel section (26a to 26I) and / or at least one second channel section (30a to 30I).

2. Heat pipe cooling element according to claim 1, characterized in that, R.408920 - 12 - that the means (34) are designed to generate a preferred flow direction of the cooling medium in the at least one channel (14), in particular by a symmetry breaking with respect to the arrangement and / or design of wave-shaped sections (36; 36a; 40; 50 to 57; 60) in the first and / or second channel sections (26a to 26I, 30a to 30I).

3. Heat pipe cooling element according to claim 1 or 2, characterized in that several, preferably periodically repeating, wave-shaped sections (36; 36a; 40; 50 to 57; 60) are provided in the at least one first channel section (26a to 26I) and / or at least one second channel section (30a to 30I).

4. Heat pipe cooling element according to one of claims 1 to 3, characterized in that corrugated sections (36; 36a; 40; 50 to 57; 60) are formed on at least two immediately adjacent first and / or second channel sections (26a to 26I, 30a to 30I), and that the corrugated sections (36; 36a; 40; 50 to 57; 60) are either identical, wherein the corrugated sections (36; 36a; 40; 50 to 57; 60) are arranged parallel to each other, i.e. without offset in the longitudinal direction in the first and / or second channel sections (26a to 26I, 30a to 30I), or that the corrugated sections (36; 36a; 40; 50 to 57; 60) are arranged on mutually facing sides of the first and / or second channel sections (26a to 26I, 30a to 30I) are formed, wherein the wave-shaped sections (36; 36a; 40; 50 to 57; 60) are arranged offset from each other in the longitudinal direction of the first and / or second channel sections (26a to 26I, 30a to 30I).

5. Heat pipe heat sink according to one of claims 1 to 4, characterized in that a straight section (37) is formed between two corrugated sections (36) in a first and / or second channel section (26a to 26I, 30a to 30I) and / or that at least one first and / or second channel section (26a to 26I, 30a to 30I) is straight. R.408920 - 13 - 6. Heat pipe heat sink according to one of claims 1 to 5, characterized in that the distances (a) between first and / or second channel sections (26a to 26I, 30a to 30I) are of different sizes.

7. Heat pipe heat sink according to one of claims 1 to 6, characterized in that the wave-shaped sections (36; 36a; 40; 50 to 57; 60) in the first and / or second channel sections (26a to 26I, 30a to 30I) extend over a different length of the first and / or second channel sections (26a to 26I, 30a to 30I) and / or are arranged offset from each other.

8. Heat pipe cooling element according to one of claims 1 to 7, characterized in that the first and / or second deflection areas (28, 32) are provided with wave-shaped sections (44).

9. Heat pipe heat sink according to one of claims 1 to 8, characterized in that a wave-shaped structure (60) is formed in the wall area of ​​the at least one wave-shaped section (36; 36a; 40; 50 to 57; 60).

10. Heat pipe heat sink according to one of claims 1 to 9, characterized in that the at least one corrugated section (36; 36a; 40; 50 to 57; 60) are sinusoidal, zigzag or circular segment-shaped.

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