CN113028869B

CN113028869B - Loop thermosiphon fin

Info

Publication number: CN113028869B
Application number: CN202110268639.8A
Authority: CN
Inventors: 褚雯霄; 谈周妥; 王秋旺; 曾敏
Original assignee: Xian Jiaotong University
Current assignee: Xian Jiaotong University
Priority date: 2021-03-12
Filing date: 2021-03-12
Publication date: 2022-02-22
Anticipated expiration: 2041-03-12
Also published as: CN113028869A

Abstract

The invention relates to a loop thermal siphon fin, wherein a fluid thermal siphon channel, a fin solid area and a liquid suction core are arranged in the fin. The fluid thermosiphon channel is annularly arranged in the fin, the lower space of the fluid thermosiphon channel is small, the upper space of the fluid thermosiphon channel is large, and filling working media can be saved in a stable fluid level state; liquid phase medium in the channel boils on the lower heat source surface and is evaporated on the upper heat source surface to become a gas phase, heat can be transferred to the tail end of the fin and condensed under the action of the buoyancy lift force, and the heat circulates to the heat source side under the action of gravity. The fin solid area is a support of the thermosiphon channel so as to ensure that the working fins do not deform when the filling working medium in the fins works under a certain pressure, the lower parts of the fins are integrally supported in a large area, and the upper parts of the fins are a plurality of small support units which are independently distributed, so that more heat exchange areas can be provided for gas phase condensation. The liquid absorption core is of a porous capillary structure and is arranged close to the upper heat source, the lower end part of the liquid absorption core is immersed in the liquid phase change medium and expands from bottom to top, and the liquid is pulled to the upper heat source and is evaporated under the action of capillary force; the upper part of the liquid absorbing core is reserved with partial space, so that the steam in the liquid absorbing core can be quickly discharged upwards and the liquid at the lower part can be supplemented.

Description

Loop thermosiphon fin

Technical Field

The invention relates to a heat dissipation device, in particular to a fin heat dissipation device based on a thermosiphon principle.

Background

With the development of science and technology, the times of internet, big data, cloud computing and artificial intelligence come, people have higher and higher requirements on the capacity and speed of network information transmission. The information transmission capability of 4G technology has become increasingly difficult to meet user needs. The generation of 5G technology with higher power density, and the accompanying higher integration and high power consumption, provides unprecedented challenges for the heat dissipation technology of the 5G base station. Due to the characteristic of high local heat flux density of the chip during working, the traditional aluminum and copper solid fins cannot obtain ideal results in solving the problem of overhigh local temperature of the base station chip, and the local heat dissipation and temperature equalization of the chip become the bottleneck problem of heat dissipation design. The blowing board is an efficient heat dissipation solution, transfers heat through evaporation and condensation of phase change media in the board, and has excellent performance in dealing with the heat dissipation problem of electronic devices with local high heat flow density and poor temperature uniformity.

The patent CN210200705U discloses a high-efficiency heat dissipation module, which comprises a base plate and a plurality of blowing plate fins with U-shaped symmetrical structures, wherein one side of the base plate is in contact with a heat source, and the other side of the base plate is provided with a plurality of blowing plate fins, so as to improve fin efficiency and achieve the purpose of rapid heat dissipation. The internal structure of the fin related in the utility model is a uniform square cavity, the liquid phase medium at the bottom is refluxed by gravity after being evaporated, and an annular flow path is not designed; meanwhile, the heat source needs to be located at the bottom section of the blowing plate, and the heat dissipation requirements of vertically arranged and higher heat sources cannot be met.

Patent CN 111750715 a discloses a composite siphon uniform temperature plate, wherein a powder filling pipeline is arranged on the lateral wall surface inside an aluminum expansion plate, and liquid phase medium is lifted to the lateral wall surface by capillary force to realize evaporation of the lateral surface, so as to solve the heat dissipation problem of the lateral heat source. The structure is not provided with an annular flow path design, and the falling of condensate in the working engineering can inhibit the rising of steam, thereby influencing the heat transfer efficiency; meanwhile, the powder filling pipeline extends from the bottom end to the top end and is completely different from the liquid absorption core structure in the patent.

The patent CN101307998A discloses a heat pipe radiator, which includes an evaporation section and a condensation section, wherein the evaporation section is divided into an upper liquid storage region, a middle evaporation region and a lower gaseous working medium release channel, and the liquid storage region, the evaporation region and the gaseous working medium release channel are connected through a capillary wick; and a partition body (similar to the integral support of a fin solid area) is connected in the condensation section connected with the evaporation section, the partition body divides the condensation section into an inner frame lower channel and an inner frame upper channel, the inner frame upper channel is communicated with the upper liquid storage area, and the inner frame lower channel is communicated with the lower gaseous working medium release channel. The gas release direction in this reference is opposite to the present application and there is no annular flow path design.

CN1506649A discloses a heat transfer device and an electronic device, the inner surface of a first substrate is provided with a groove, the groove constituting an evaporator, and the groove, the groove constituting a condenser. The vapor channels have straight channels and the cross-sectional area may vary gradually, widening from the evaporator to the condenser. The comparison document provides capillary force by using the change of the cross section area of the channel, a non-uniform capillary core structure is not seen, and the horizontal flow and heat dissipation of gas and liquid of the invention are different from the heat dissipation problem in the vertical direction of the application.

Disclosure of Invention

The technical scheme for solving the problems is as follows:

providing a loop thermosiphon fin which is formed by welding or blowing two layers of thin plates, wherein one end of the fin absorbs heat from a heat source; the fin is externally provided with a refrigerant filling port, and the fin is internally provided with a fluid thermosiphon channel, a fin solid area and a liquid absorption core; the fluid thermosiphon channel is annularly arranged, a phase-change working medium is filled in the channel, the working medium absorbs heat from a heat source at one end of the channel, namely an evaporation area of the working medium, and transfers to the other side of the channel under the action of buoyancy lift force, namely the tail end of the fin is condensed, the working medium can circulate to the evaporation area through the fluid thermosiphon channel under the action of gravity, the evaporation area is divided into an upper heat source surface and a lower heat source surface by taking the middle position of the fin as a boundary, the heat transfer of the upper heat source surface is mainly based on an evaporation mechanism, and the lower heat source surface is mainly based on a boiling mechanism. The fin solid area provides support for the fluid thermosiphon channel, and can adopt a large-area integral support or a plurality of small solid unit support modes which are independently distributed by matching with the upper channel space and the lower channel space. The liquid absorption core is of a porous capillary structure, gradually expands from bottom to top and is arranged close to the upper heat source surface, the lower end part of the liquid absorption core is immersed in the liquid-phase medium, and the liquid-phase medium is lifted to the upper heat source surface by capillary force to carry out evaporation heat exchange; the space of the top of the liquid absorbing core is reserved to facilitate the discharge of steam in the liquid absorbing core. The refrigerant filling port is kept closed when the thermosiphon fin works and is opened during debugging so as to be used for vacuumizing and filling the phase change medium.

The preferable scheme further comprises any one of the following technical characteristics:

the solid fin is divided into an upper part and a lower part, the upper part is provided with a plurality of small units which are independently distributed, the working fins are ensured not to deform when the working medium is filled in the fins under certain pressure, more heat exchange areas are provided for gas phase condensation, and the lower part is provided with a large-area integral supporting unit which gradually shrinks upwards from the bottom.

The fluid thermal siphon channel forms a loop around the fin solid area, the fluid thermal siphon channel on the upper portion of the fin is high in occupied ratio, the solid area on the lower portion of the fin is high in occupied ratio, the arrangement form of the fluid thermal siphon channel with small lower space and large upper space is presented, filling working media can be saved under a stable fluid liquid level, and the starting speed of the thermal siphon fin is increased.

The liquid absorption core has a porous characteristic, is arranged on the inner wall of the thermosiphon channel and is close to the upper heat source, the lower end part of the liquid absorption core is immersed in the liquid phase change medium, an anisotropic structure with gradient porosity can be adopted in the liquid absorption core according to requirements, the porosity is gradually reduced from bottom to top, and the porosity is gradually reduced from a heat source end to a heat source end, so that a larger capillary force is provided, and the pulling-up effect of the working fluid is improved; the volume of the liquid-absorbing part of the liquid absorbing core can be adjusted according to the liquid absorbing quantity requirement.

The top of the liquid absorption core is provided with a reserved space, and liquid in the liquid absorption core can be quickly discharged upwards after being evaporated, so that the liquid in the liquid absorption core can be supplemented.

The inner wall surface of the thermosiphon channel can adopt a hydrophilic surface or a hydrophobic surface, so that the surface wetting can be promoted, the safety is improved, and the working medium circulation efficiency is improved.

The loop thermosiphon fin and one surface of the base can be connected in a welding, riveting and other connection modes, and the middle interface can be filled with a heat conduction material so as to reduce the heat conduction thermal resistance between the root of the fin and the base.

The invention also provides a loop thermosiphon heat dissipation module which consists of a base and at least one loop thermosiphon fin and is used for dissipating heat of a plane heat source or a plurality of groups of heat source arrays in the plane. The connection of the loop thermosiphon fin and one side of the base can be in any form of welding, riveting, assembling and the like.

Compared with the prior art, the invention has the following effects:

according to the loop thermosiphon fin, the phase change working medium in the fin absorbs heat from the heat source at the evaporation end, the liquid phase working medium is boiled and converted into a gas phase, the gas phase is transferred to the tail end of the fin under the action of the buoyancy lift force and is condensed into a liquid phase, and the liquid phase working medium circulates to the evaporation end under the action of gravity. Compared with the traditional gravity type heat pipe in the mode of evaporation and condensation in the same space, the arrangement of the separation evaporation and condensation surface effectively prevents the condensate from falling to inhibit boiling, improves the surface temperature uniformity and the fin efficiency of the fin, and effectively improves the local overheating problem of electronic devices.

According to the loop thermosiphon fin, the liquid absorption core arranged in the fin can lift the liquid-phase working medium upwards to wet the upper heat source, and takes away heat under the action of the evaporation mechanism, so that the problem of evaporation of the upper heat source is effectively solved, and the failure caused by overhigh local junction temperature of the upper electronic part is prevented.

The loop thermosiphon fin is a self-adaptive and self-maintaining high-efficiency heat dissipation device without moving parts, the heat dissipation mode of the loop thermosiphon fin belongs to passive heat dissipation, and compared with an active heat dissipation mode of forced convection driven by a fan, the loop thermosiphon fin can effectively reduce the junction temperature and the failure rate of a product, and is noiseless and vibration-free.

Drawings

FIG. 1 is a schematic structural view of a loop thermosiphon fin according to the present invention;

FIG. 2 is a perspective view of a loop thermosiphon heat dissipation module according to the present invention;

description of reference numerals:

1-a fin; 2-a fin solid region; 3-fin ends; 4-a fluid thermosiphon channel;

5-liquid phase medium; 6-refrigerant filling port; 7-a gas-phase medium; 8-a wick;

9-upper heat source surface; 10-lower heat source surface; 11-reserving space; 12-a base;

Detailed Description

Fig. 1 is a schematic view of the structure of a loop thermosiphon fin of the present invention.

The present invention will be described in detail below with reference to the accompanying drawings. A loop thermal siphon fin 1 is formed by welding or blowing two layers of thin plates, a refrigerant filling opening 6 is arranged outside the fin, and a fluid thermal siphon channel 4, a fin solid area 2 and a liquid suction core 8 are arranged inside the fin. The fluid thermosiphon channel 4 is annularly arranged in the fin, phase-change working media (5,7) are filled in the channel, the working media absorb heat from a heat source at one end of the channel, namely an evaporation area of the working media, the evaporation area is divided into an upper heat source surface (9) and a lower heat source surface (10) by taking the middle position of the fin as a boundary, the heat transfer of the upper heat source surface (9) is mainly an evaporation mechanism, the lower heat source surface (10) is mainly a boiling mechanism, the lower heat source surface is transferred to the other side of the channel under the action of buoyancy lift force, namely the tail end 3 of the fin is condensed, and the working media circulate to the evaporation area through the fluid thermosiphon channel 4 under the action of gravity. The fin solid area 2 provides support for the fluid thermosiphon channel 4, the lower space of the channel is smaller, the upper space of the channel is larger, the fin solid area 2 supports the fluid thermosiphon channel 4, the fin solid area is adjusted according to the change of the channel arrangement, and meanwhile, the fin solid area is provided with a large-area integral support unit and a plurality of small units which are independently distributed. The liquid absorption core 8 is of a porous capillary structure, gradually expands from bottom to top and is arranged close to the upper heat source surface 9, the lower end part of the liquid absorption core 8 is immersed in the liquid-phase medium 5, and the liquid-phase medium 5 is lifted to the upper heat source surface 9 through capillary force to carry out evaporation heat exchange. The refrigerant filling port 6 is kept closed when the thermosiphon fin works, and is opened during debugging to vacuumize and fill the phase change medium.

The heat source surfaces (9,10) of the loop thermal siphon fin are attached to the heat generating parts of the electronic device, and when the heat source surfaces (9,10) are heated, the liquid-phase medium 5 in the fluid thermal siphon channel 4 boils on the lower heat source surface 10, is pulled up through the wick 8 to the upper heat source surface 9, and is evaporated into the gas-phase medium 7. The gas-phase medium 7 transfers heat to the tail ends 3 of the fins under the action of the buoyancy lift force and is condensed to release heat, and the liquid-phase medium circulates to the heat source surface (9,10) through the fluid thermal siphon channel 4.

Preferably, the solid fin area is divided into an upper part and a lower part, the upper part is a plurality of small-sized units which are independently distributed, the working fins are guaranteed not to deform when filled with working media under certain pressure, more heat exchange areas are provided for gas phase condensation, and the lower part is a large-area integral supporting unit which gradually shrinks upwards from the bottom.

Preferably, the fluid thermal siphon channel forms a loop around the fin solid area, the fluid thermal siphon channel at the upper part of the fin has high occupation ratio, the solid area at the lower part of the fin has high occupation ratio, and the arrangement form of the fluid thermal siphon channel with small lower space and large upper space is presented, so that the filling working medium can be saved under the stable fluid liquid level, and the starting speed of the thermal siphon fin can be improved.

Preferably, the liquid absorption core has a porous characteristic, is arranged on the inner wall of the thermosiphon channel and is close to the upper heat source, the lower end part of the liquid absorption core is immersed in the liquid phase change medium, an anisotropic structure with gradient porosity can be adopted in the liquid absorption core according to requirements, the porosity decreases from bottom to top, and the porosity decreases from a position far away from the heat source end to the heat source end, so that higher capillary force is provided, the pulling-up effect of the working fluid is improved, and the surface of the upper heat source is wetted.

Preferably, the top of the liquid absorption core is provided with a reserved space 11, and liquid in the liquid absorption core can be quickly discharged upwards after being evaporated, so that the liquid in the liquid absorption core can be supplemented.

Preferably, the inner wall surface of the thermosiphon channel can adopt a hydrophilic surface or a hydrophobic surface, so that the surface wetting can be promoted, the safety is improved, and the working medium circulation efficiency is improved.

Fig. 2 is a perspective view of a loop thermosiphon fin heat dissipation module according to the present invention.

The present invention will be described in detail below with reference to the accompanying drawings. A loop thermosiphon heat dissipation module comprises a base 12 and at least one loop thermosiphon fin 1 and is used for dissipating heat of a plane heat source or a plurality of groups of heat source arrays in a plane. The loop thermosiphon fin 1 can be attached to the base 12 by welding, riveting and the like, wherein an intermediate contact surface can be filled with a heat conduction material so as to reduce heat conduction resistance between the root of the fin and the base. The base 12 can be directly attached to the heating element, or attached to the heat source after being connected to the temperature equalization plate, and the attaching surface is also filled with heat conduction materials to reduce the contact thermal resistance.

The embodiments of the present invention are merely exemplary and not intended to limit the scope of the patent, and those skilled in the art may make modifications to the embodiments without departing from the spirit and scope of the patent.

Claims

1. A loop thermosiphon fin, comprising: a fluid thermal siphon channel, a fin solid area and a liquid suction core are arranged in the liquid storage tank; the fluid thermosiphon passageway is the annular and arranges that the one end of fin inner passage is from the heat source heat absorption, for the evaporation zone, the evaporation zone uses the fin intermediate position to divide into heat source face and heat source face down as the boundary, and the passageway other end is the condensation zone, and the fin is terminal promptly, and the lower part space of passageway is less and the upper portion space is great, fin solid district is the support of fluid thermosiphon passageway, according to the change adjustment that the passageway arranged, possesses the whole supporting element of large tracts of land and a plurality of small-size supporting element who independently distributes simultaneously, the imbibition core is porous capillary structure, expands gradually from bottom to top, and presses close to the heat source and arranges the imbibition core, and the lower part submergence is in liquid phase transition medium.

2. The loop thermosiphon fin of claim 1, wherein: the fin solid area is divided into an upper part and a lower part, and the upper part is provided with a plurality of small supporting units which are independently distributed; the lower part is a large-area integral supporting unit which gradually shrinks upwards from the bottom.

3. The loop thermosiphon fin of claim 1, wherein: the fluid thermal siphon channel forms a loop around the fin solid area, the fluid thermal siphon channel occupation ratio at the upper part of the fin is high, the solid area occupation ratio at the lower part of the fin is high, and the fluid thermal siphon channel arrangement mode with small lower space and large upper space is presented.

4. The loop thermosiphon fin of claim 1, wherein: the liquid absorption core has a porous characteristic, an anisotropic structure with gradient porosity can be adopted in the liquid absorption core according to requirements, the porosity is gradually reduced from bottom to top, and the porosity is gradually reduced from a heat source end to a heat source end.

5. The loop thermosiphon fin of claim 1, wherein: the top of the liquid absorption core is provided with a reserved space, and liquid in the liquid absorption core can be quickly discharged upwards after being evaporated, so that the liquid in the liquid absorption core can be supplemented.

6. The loop thermosiphon fin of claim 1, wherein: the inner wall surface of the thermosiphon channel adopts a hydrophilic or hydrophobic surface.

7. The utility model provides a loop thermosiphon heat dissipation module which characterized in that: a thermal siphon heat exchanger comprising a base and at least one loop thermosiphon fin as claimed in any one of claims 1 to 6 for dissipating heat from a planar heat source or an array of in-plane groups of heat sources.