WO2007124652A1

WO2007124652A1 - Micro-slot group integrated heat-pipe radiator

Info

Publication number: WO2007124652A1
Application number: PCT/CN2007/000804
Authority: WO
Inventors: Hongwu Yang
Original assignee: Hongwu Yang
Priority date: 2006-04-30
Filing date: 2007-03-13
Publication date: 2007-11-08
Also published as: CN1851911A

Abstract

A micro-slot group integrated heat-pipe radiator, including a closed shell (1) made of metal thin plates, in which, the inside cavity of the shell (1) is vacuum filled with working fluid, a core (3) piled up closely by multiple metal thin sheets (2) are set in the closed shell, the outer surface of the core (3) is welded to the internal surface of the shell (1), gaps generating capillary force to adsorb the working fluid is set between the metal thin sheets (2), the surface of the sheet (2) is opened with through holes (4), multiple through holes (4) which are piled up form through apertures on the core (3) to drive the boiled fluid to flow among the slots adjacent to said metal thin sheets.

Description

Micro-slot clustering into heat pipe radiator

The invention relates to a micro-slot clustering into a heat pipe radiator, in particular to a micro-groove group in which a closely overlapping metal foil is arranged in a cavity of a casing to generate capillary force to adsorb liquid working medium and at the same time provide internal support for the heat pipe radiator. Integrated heat pipe radiator. Background technique

With the rapid development of microelectronics technology, the integration degree of integrated circuits has been greatly improved, and the heat dissipation of electronic components has become a technical bottleneck restricting the miniaturization, operation speed, and output power of electronic devices.

Taking the computer CPU chip as an example, its integration has increased by nearly 20,000 times in 30 years, and the heat flow generated by it has reached 100 W/cm ² . As we all know, the reliability and longevity of computer work are closely related to its working temperature. The higher the integration of electronic chips, the higher the heat generated. If the heat cannot be dissipated in time, the reliability of the computer will be It will be greatly reduced, and even there will be cases where it is not working properly.

The combination of the traditional fan and heat sink has been difficult to meet the heat dissipation of high-performance chips. Some people have proposed to use the principle of liquid-gas heat transfer to solve the problem of electronic heat dissipation, that is, to use the heat pipe heat transfer principle to dissipate heat from the electronic components. This type of heat dissipation is highly efficient and has gradually become the most important form of cooling for electronic chips in notebook computers and desktops.

In order to improve the heat dissipation capability of the heat pipe radiator, the researchers mainly studied from two ways, one is the miniaturization of the heat pipe, including the micro heat pipe, the pulsating heat pipe and the micro channel heat pipe; the other is to increase the heat pipe phase by changing the heat pipe structure. Change the contact area. This is because the bottleneck limiting the heat pipe capacity is not in the heat transfer process, but the existing heat pipe structure cannot ensure sufficient phase change contact area during the phase change process.

The trend of miniaturization of heat pipes is now mainly focused on the technology of microchannels, which mainly solves problems. How to produce microchannels at low cost. The study of large phase change contact area is mainly focused on changing the heat pipe structure. The main problem to be solved is how to increase the phase change contact area and ensure the strength and rigidity of the heat pipe. As shown in FIG. 1 , it is a schematic structural view of a sheet-fed wick in the heat pipe radiator of the prior art. The heat pipe radiator adopts a plurality of stamped and formed metal foils arranged side by side to be arranged in parallel to form a liquid absorbing liquid. The core, the spacing between the foils forms a wick channel. In the manufacture of such a heat pipe heat sink, a plurality of stamped metal foils need to be welded or affixed side by side on the surface of the heat pipe heat sink cavity, and the wicking channel is usually small, so that a large capillary force can be generated. The condensed liquid working fluid quickly returns. The wick made of these metal foils makes the evaporation and condensation area of the liquid working medium much larger than the phase change contact area of the heat absorbing end and the condensing end of the heat pipe radiator, thereby achieving a good heat dissipation effect.

However, the metal foil used in the wick of the heat pipe radiator is usually thin and has low strength, and the mounting and positioning of the sheet are difficult. Therefore, it is necessary to open a card for the card at the end edge of the foil. Slots or flanges to improve the accuracy and reliability of installation and positioning. As shown in Fig. ² , a schematic diagram of a wick structure for pressing a plurality of bumps on the surface of the longitudinal metal foil is complicated, and the supporting effect is relatively poor. . Summary of the invention

The first object of the present invention is to solve the problem of the complicated structure and processing procedure of the existing heat pipe radiator, and propose a micro-slot clustering into a heat pipe radiator, which has good performance of adsorbing liquid working medium and has good transmission. Thermal conductivity.

The second object of the present invention is to solve the problem of the complicated structure and processing procedure of the existing heat pipe radiator, and proposes a micro-slot clustering into a heat pipe radiator, which can simplify the processing process and the heat pipe radiator structure, thereby improving production efficiency. reduce manufacturing cost.

The third object of the present invention is to solve the problem of the complicated structure and processing procedure of the existing heat pipe radiator, and proposes a micro-slot clustering into a heat pipe radiator, which can be made into various shapes to meet the narrow irregular space of the notebook. Claim. In order to achieve the above object, the present invention provides a microslot clustered into a heat pipe heat sink, comprising a closed casing made of a thin metal plate, the inner cavity of the closed casing being vacuumed and filled with a liquid working medium, and characterized A core body in which a plurality of metal foils are closely stacked is disposed in the closed casing, and an outer surface of the core body is welded to an inner surface of the closed casing, and the metal foil is capable of being used for generation a slit for adsorbing the capillary force of the liquid working medium; the surface of the metal foil is provided with a through hole, and the plurality of through holes form a through hole in the core body for allowing the vaporized liquid working medium to be in the closed casing Circulation.

The gap between the metal foils constitutes a microgroove group structure having a plurality of microchannels communicating with each other. Due to the small size of the microchannel, the liquid working medium in the microchannel is affected by the large capillary action. When the liquid working fluid produces a single phase flow in the microchannel, the temperature of the liquid flow center is lower than that of the liquid close to the wall. The temperature, which is uneven, causes uneven surface tension, which produces the Maragoni effect. The Maragoni effect helps to overcome the viscous force, reduces the fluid resistance, and reduces the critical Reynolds number of the laminar flow to the turbulent transition, thereby accelerating the flow of liquid in the microchannel.

Increasing the circulation of the liquid working medium can also speed up the heat dissipation and make the heat dissipation inside the heat sink more uniform. Therefore, the through holes opened at the same or adjacent positions on the surface of the metal foil can make the vaporized liquid working medium in the closed shell. The body and the adjacent slits of the metal foil circulate between each other.

A plurality of through holes may be provided in the metal foil at a position in the middle of the direction of the vertical heat absorbing base of the metal foil or the upper or lower edge of the metal foil. The cross-sectional shape of the through hole may be a rectangle, a circle, an ellipse or a triangle, and the cross-sectional shape of the adjacent through holes may be the same or different.

In order to circulate the liquid working fluid between adjacent channels, a plurality of notches are formed in the upper and/or lower edges of the metal foil. The notches of each of the adjacent metal foils may be disposed at the same position on the surface to form a through groove on the upper and lower surfaces of the core. The notches of each adjacent metal foil may also be staggered to form curved grooves on the upper and lower surfaces of the core.

The core body can be stamped into a gasket-like core having the same contour as the inside of the casing by using a metal foil The outer contour is formed by using a plurality of metal foils to be stamped into a gasket-like metal foil having the same contour as the inner contour of the casing. The surface of the gasket-shaped metal foil is provided with a steam through hole, and the metal solid portion between the two through holes constitutes a core. The support of the body, the metal body between the through hole and the outer contour of the gasket is a rib constituting the microgroove, wherein the gap between any two gaskets of the core constitutes a channel of the core, and the spacing between the channels The assembly position with the gasket can be achieved by punching the uneven spots on the surface of the gasket. When a gasket is used to form the core body, the adjacent steam passages form a passage due to the gap between the shells in which the cores are parallel; when two or more gasket-like metal foils are used to form the core body, the support of the two gaskets is staggered from each other. The through holes are misaligned and the steam passages are kept continuous with each other. It is also possible to directly laminate a plurality of metal foils of the same shape to form a core, and the shape of the metal foil may be a rectangle, or an inverted trapezoid or the like. The core body composed of such a gasket-like metal foil is generally used for an integrated heat pipe structure having a three-dimensional steam passage, wherein the three-dimensional steam passage generally refers to a distribution of the steam chamber along a three-dimensional space.

The core may also be an outer contour foil strip having parallel distances, the strip surface is provided with a steam through hole, the metal solid portion between the two through holes constitutes a support of the core body, and the metal between the through hole and the outer contour of the strip The solid is the rib that forms the microgroove, wherein the gap between any two of the ribs of the core constitutes a channel of the core. The strip-shaped metal foil may be continuously wound by a group, two or more sets of strips to form a core of the planar heat pipe, and the core body may be in the form of a disk or a square disk or an L-shape or a T-shape. A radial metal foil may be provided in the center of the disk or the square disk.

The closed casing of the micro-slots formed into the heat pipe radiator may be a casing without an inner cooling fluid passage, or an inner cooling fluid passage may be disposed on the closed casing, that is, one or more sets of the inner casing are disposed at the center of the closed casing. Rectangular or circular or elliptical cylindrical cold fluid passages that increase the heat sink area of the heat sink for higher heat dissipation efficiency.

In order to increase the heat dissipation area, a plurality of heat dissipation fins perpendicular to the metal foil may be welded to the outer surface of the closed casing.

According to the above description of the technical solution, the present invention can be found to have the following advantages:

1. The core body is composed of closely-stacked metal foils, which can be compacted in the manufacture and then welded into the closed casing, and the manufacturing process is relatively simple. 000804

2. The gap between the closely stacked metal foils forms a micro-groove group structure, which can accelerate the flow of the liquid working medium and increase the phase change contact area, thereby providing good heat dissipation capability.

3. After the metal foil in the core body is closely stacked, it is welded in the closed casing. Since the core body has a good supporting structure, the overall strength and rigidity are high, and there is no internal pressure change in the working state. The deformation problem of the closed casing. '

4. The shape of the core can be designed according to the size of the heating element and the space in which it is placed. It can be made into a flat radiator or an irregular shaped plate or a heat pipe radiator with a three-dimensional steam chamber, so that it has good adaptability.

The technical solution of the present invention will be further described in detail below through the accompanying drawings and embodiments. DRAWINGS

1 is a schematic view showing the structure of a sheet-channel wick in the heat pipe radiator of the prior art. Fig. 2 is a schematic view showing the structure of a wick which is provided with a plurality of bumps on the surface of the longitudinal metal foil.

FIG. 3 is a schematic structural view of Embodiment 1 of the microslot clustering heat pipe heat sink of the present invention.

Figure 4 is a schematic cross-sectional view of the foil after welding to the inner cavity of the closed casing.

Fig. 5 is a schematic view showing the structure of a metal foil having an elliptical through hole.

Fig. 6 is a schematic view showing the structure of a metal foil having a rectangular through hole.

Fig. 7 is a schematic view showing the structure of a metal foil having a circular through hole.

Fig. 8 is a structural schematic view of a metal foil having a through hole opened at an upper edge or a lower edge.

Fig. 9 is a schematic view showing the lamination method of directly laminating the metal foil.

Figure 10 is a schematic diagram of the lamination method of bending and lamination of the metal foil.

Fig. 11 is a schematic view showing a lamination method in which a metal foil is bent and laminated into an irregular shape.

FIG. 12 is a schematic structural view of Embodiment 2 of the microslot clustering heat pipe heat sink according to the present invention. Figure 13 is a schematic cross-sectional view of the foil after welding to the inner cavity of the closed casing.

Figure 14 is a schematic view showing the structure of a plurality of sets of core bodies stacked with different core units. FIG. 15 is a schematic structural view of a third embodiment of a micro-slot clustering heat pipe heat sink according to the present invention. FIG. 16 is a schematic structural view of a fourth embodiment of a micro-slot clustering heat pipe heat sink according to the present invention. Fig. 17 is a schematic view showing a winding manner in which a metal foil is wound into a circular shape.

Fig. 18 is a schematic view showing a winding manner in which a metal foil is wound into a rectangular shape.

Fig. 19 is a schematic view showing a winding manner in which a metal foil is wound into a circular shape with a circular radial core. detailed description

The invention utilizes the Maragone effect of the micro-groove group to enhance the flow disturbance effect, enhances the heat exchange, and increases the reflow speed of the liquid working medium by utilizing the strong liquid absorption capacity of the micro-channel, thereby achieving the effect of accelerating heat dissipation. See the examples below for specific construction.

Embodiment 1

As shown in Fig. 3, it is a schematic structural view of the first embodiment of the present invention. The heat pipe radiator of this embodiment includes a closed casing 1, a core 3, and a liquid working medium (not shown), the body of which is completely sealed, the internal cavity thereof is evacuated, and poured A certain amount of liquid working medium; the core 3 is a unitary body formed by tightly laminating the metal foil 2, and the outer surface of the core body 3 is connected to the inner cavity of the closed casing 1 by brazing during installation. The metal foil 2 is provided with a through hole 4 through which liquid working fluid for vaporization flows between adjacent slits of the metal foil, and the core 3 forms a through hole at the position of the through hole 4. Heat-dissipating fins 5 perpendicular to the metal foil 2 are welded to the outer surface of the closed casing 1, and a passage for cooling air is left between the heat-dissipating fins 5.

Since the internal pressure changes very sharply during the operation of the heat pipe, sometimes a very high pressure value is reached, and in order to ensure the heat dissipation speed of the heat pipe, the wall of the casing is usually thin, so the wall of the casing is easily continuous due to the change of pressure. The expansion or contraction causes the solder joints in the weld of the casing to loosen, causing the heat pipe vacuum chamber to leak and the radiator to fail. The heat sink in this embodiment adopts a monolithic core as a wick, and the core has good strength and rigidity, and the core and the seal A firm welding method between the closed casings allows them to be unaffected by changes in air pressure during operation. In addition, heat-dissipating fins perpendicular to the metal foil are welded to the outer surface of the closed casing, and the heat-dissipating fins and the inner metal foil can form a support of the closed form of the closed casing, and have very good strength.

In order to make the liquid working medium flow between the metal foils to accelerate the reflow speed, the upper and lower edges of the metal foil may be notched on the basis of the embodiment, as shown in FIG. 4, after the metal foil is welded to the inner cavity of the closed casing. A schematic cross-sectional view, the metal solid portion 1 1 between the through holes 4 is a support of the core body, the solid portion of the through hole and the upper edge of the metal foil 2 is the rib 8a, and the solid portion of the through hole and the lower edge of the metal foil 2 is The rib 8b, in this embodiment, the lower side is a heat absorbing end. The rib 8 and the closed casing 1 have a welded layer 6 welded by brazing. A plurality of notches 7 are formed in the upper and lower edges of the metal foil 2, and the notches 7 may be opened at the same position of the metal foil so that the core body 3 forms a straight straight groove; or the adjacent metal foils are staggered, A curved groove is formed.

The gap between the ribs 8a of the adjacent metal foils and the ribs 8b constitutes the upper and lower channels, and the spacing between the channels and the position of the gasket between the gaskets can be passed through the gasket The surface of the metal foil is punched into the concave and convex points. The liquid working fluid can be acceleratedly recirculated through the upper and lower channels, and the metal solid portion 11 (ie, the supporting portion 1 1 ) between the through holes 4 serves as a support for the core to provide good strength and rigidity to the closed casing. When the air pressure inside the casing changes, the deformation of the casing can be prevented due to the action of the support. In the flow of the liquid working medium, the gap between the supporting portions 11 of the adjacent metal foils can also serve as a mutual passage for the upper and lower channels, so that the gaps 7 of the upper and lower edges of the metal foil form a three-dimensional direction of the liquid working medium. The circulation, which accelerates the return of the liquid working fluid.

The cross-sectional shape of the through hole 4 may be elliptical, circular, rectangular, triangular or irregular, as shown in Fig. 5-7. During processing, for processing convenience, it may be directly on the upper side or the lower side of the foil 2. A through hole is formed in the long side, as shown in FIG. 8, which is a schematic structural view of a metal foil having a through hole at the upper edge, wherein the lower edge is a heat absorbing end. In the production of the core, there are many ways to laminate the metal foil, see Figures 9-11, wherein the core shown in Figure 9 is formed by directly laminating a plurality of foils having the same outer contour, Figure 10 The core shown is composed of a narrow-band metal foil wound into a gasket-like metal foil having the same contour as that of the casing, or a plurality of narrow-band metal foils may be wound or stamped into the contour of the casing. The same gasket-like core outer contour is constructed. When a gasket is used to form the core body, the adjacent steam passages form a passage due to the gap between the shells in which the cores are parallel; when two or more gasket-like metal foils are used to form the core body, the support of the two gaskets is staggered from each other. The through holes are misaligned and the steam passages are kept continuous with each other. The core shown in Fig. 11 is formed by bending a narrow strip of metal foil, and the core can be stacked into an irregular shape according to the use condition (for example, a space for accommodating the heat sink), as shown in Fig. 11. The shape is approximate "L".

When the micro-slots of the present invention are assembled into a heat pipe radiator, the heat-absorbing substrate absorbs heat transferred by the electronic device, and the local temperature of the liquid working medium absorbs heat, and when the evaporation condition is reached, the liquid working medium is rapidly heated. The vaporized, vaporized liquid working medium circulates to a liquid through a through hole to a lower temperature position, and the micro-groove group produced by the present invention can realize the Maragone effect, thereby enabling the condensed liquid working medium to be rapidly Returning to the heat absorbing substrate enhances heat transfer.

Embodiment 2

As shown in Fig. 12, it is a schematic structural view of a second embodiment in which the microgrooves of the present invention are assembled into a heat pipe radiator. The previous embodiment is a flat plate type flat heat sink, and this embodiment is a heat sink with a cold fluid passage. In FIG. 12, the middle portion of the closed casing is a cylindrical cold fluid passage 9 having a rectangular cross section, and a plurality of heat radiating fins 5 are disposed in the cold fluid passage 9 and the outer surface of the closed casing, and the heat radiating fins 5 are provided. The metal foil 2 is welded perpendicularly to the cold fluid passage 9 and to the outer surface of the closed casing. During operation, these fins can quickly dissipate heat from the heat pipe radiator under the action of cold air.

As shown in FIG. 13 , which is a schematic cross-sectional view of the metal foil and the inner cavity of the closed casing, the metal foil 2 has a hollow rectangular shape, and a gap between the ribs 8a of the adjacent metal foil and the rib 8b. The upper and lower channels are formed, and the spacing between the channels and the assembly position between the spacers can be achieved by punching the uneven spots on the surface of the spacer. The liquid working medium can be acceleratedly recirculated through the upper and lower channels, and the metal solid portion 11 (ie, the supporting portion 11) between the through holes 4 as a support of the core body can provide the closed casing with good strength and rigidity. When the air pressure inside the casing changes, the deformation of the casing can be prevented due to the action of the support. In the flow of the liquid working medium, the gap between the supporting portions 11 of the adjacent metal foils can also serve as a mutual passage for the upper and lower channels, so that the gaps 7 of the upper and lower edges of the metal foil form a three-dimensional direction of the liquid working medium. The circulation, which accelerates the return of the liquid working fluid. The broken line portion in Fig. 13 indicates the edge of the through hole of the adjacent metal foils stacked together, and the through holes of the adjacent metal foils are staggered, and the steam passages formed therebetween are kept continuous with each other. The core 3 formed after lamination forms a rectangular passage in the hollow portion, and the edge of the rectangular passage is welded to the inner surface of the cold fluid passage 9 of the closed casing. At the bottom of the heat sink is an endothermic substrate 10 which, in use, is typically in intimate contact with the electronics requiring heat dissipation to reduce thermal resistance. The cold fluid passage may also be a cylindrical passage of other shapes such as a circular or elliptical shape.

As shown in FIG. 14 , a schematic structural view of a core body in which a plurality of different core units are stacked, the metal foil can be stacked into a plurality of core units of different thicknesses and different through hole positions, and then the core units are composed. In the core of the heat sink, in FIG. 14, the core unit A, the core unit B, and the core unit C are different, and the core units may be stacked in any order, and the positions of the through holes may be different, but Must have the same outer contour. This makes it easy to manufacture heat sinks of different thicknesses. Manufacturers can make standard core units and stack these standard core units depending on the application to achieve the desired core structure.

Embodiment 3

As shown in FIG. 15 , it is a schematic structural view of a third embodiment of a micro-slot clustering heat pipe heat sink according to the present invention. The difference between the embodiment and the first embodiment is that the cross-section is different. In this embodiment, a flat-plate heat pipe with a trapezoidal cross-section is used. The length of the heat absorbing substrate 10 of the structure is smaller than the length of the upper edge, and can be placed on a small electronic device, so that it can dissipate heat for a smaller electronic device. Good heat dissipation. In order to accelerate the heat dissipation, it is also possible to provide a heat dissipating fin perpendicular to the metal foil 2 on the surface of the closed casing 1. Further, the core body 3 of the present embodiment is a disk-shaped flat heat pipe which is formed by winding a strip and which is formed from a contour to a height.

Embodiment 4

As shown in Fig. 16, the structure of the fourth embodiment in which the microgrooves of the present invention are formed into a heat pipe radiator is shown. This embodiment is an annular closed casing 1, and the inside is an annular core 3, and the core 3 can be wound into a ring-shaped core or a core of a solid disk by a high-speed winder.

There are many ways to wind up. See Figure 17-19. Figure 17 is a schematic view of the winding of the foil in a circular shape. Figure 18 is a schematic view of the winding of the foil in a rectangular shape. Figure 19 is a foil. A schematic view of a winding pattern that is wound into a circular shape with a circular radial core.

It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not to be construed as limiting thereof; although the present invention will be described in detail with reference to the preferred embodiments, those skilled in the art should understand that The invention is not limited to the spirit of the technical solutions of the present invention, and should be included in the scope of the technical solutions claimed in the present invention.

Claims

Claim

A micro-slot clustered into a heat pipe heat sink, comprising a closed casing made of a thin metal plate, the inner cavity of the closed casing being vacuumed and filled with a liquid working medium, characterized in that, in the closed casing a core body composed of a plurality of metal foils closely stacked, the outer surface of the core body being welded to the inner surface of the closed casing, and the metal foil having a capillary force capable of generating a liquid working medium for adsorption a slit; the surface of the metal foil is provided with a through hole, and the plurality of through holes form a through hole in the core for circulating the vaporized liquid working medium in the closed casing.

2. The microslot clustering heat pipe heat sink according to claim 1, wherein the number of the through holes is plural, and is disposed in a middle or upper direction in a direction of the vertical heat absorbing bottom plate of the metal foil. Edge or bottom edge.

3. The microslot clustering heat pipe heat sink according to claim 2, wherein the through hole has a rectangular or circular or elliptical shape or a triangular shape.

The heat sink heat sink according to claim 2, wherein the upper edge or the lower edge of the metal foil is further provided with a plurality of notches for forming liquid communication between adjacent channels. aisle.

The heat sink heat sink according to claim 4, wherein the notches are provided at the same position on the surface of the metal foil, and a through groove is formed in the upper and lower surfaces of the core.

The heat sink heat sink according to claim 4, wherein the notch is staggered in the adjacent metal foil, and the upper and lower surfaces of the core are curved.

7. The microgroove clustered heat pipe heatsink of claim 1 wherein the core body is formed by continuously bending one or more of the metal foils into the same outer contour.

8. The micro-slot clustering heat pipe heat sink according to claim 1, wherein the core body is formed by laminating the metal foils of a plurality of identical outer contours.

9. The micro-slot clustering heat pipe heat sink according to claim 1, wherein The core body is formed by continuously winding one of the metal foils.

10. The microgroove cluster heat pipe heat sink according to claim 1, wherein the core body is formed by stacking a plurality of closely stacked metal foils.

11. The microgroove clustered heat pipe heatsink of claim 1 wherein the closed casing has a cylindrical cold fluid passage having a rectangular or circular or elliptical cross section.

The micro-slot clustered heat pipe heat sink according to any one of claims 1 to 11, wherein a plurality of heat-dissipating fins perpendicular to the metal foil are welded to an outer surface of the closed casing.