CN212158264U

CN212158264U - Loop heat pipe evaporator with composite heat sink and loop heat pipe system

Info

Publication number: CN212158264U
Application number: CN202020342361.5U
Authority: CN
Inventors: 陈振乾; 贺李丹
Original assignee: Southeast University
Current assignee: Southeast University
Priority date: 2020-03-18
Filing date: 2020-03-18
Publication date: 2020-12-15
Anticipated expiration: 2030-03-18

Abstract

The utility model discloses a loop heat pipe evaporator with composite heat sink and a loop heat pipe system, which comprises an evaporator shell, a liquid storage cavity, a gas collection chamber, a liquid absorption core and a heat sink; the evaporator shell is of a flat plate type cavity structure, working media are filled in the evaporator shell, the left side wall and the right side wall of the evaporator shell are respectively provided with an evaporator liquid inlet and an evaporator gas outlet, and the outer wall surface of the bottom of the evaporator shell is attached to the heat sink; the heat sink is of a sheet-like structure; the liquid absorption core is an integral body, and a plurality of steam channels are processed; the evaporator shell is internally provided with the liquid storage cavity and the gas collection chamber, the liquid storage cavity is communicated with the liquid inlet of the evaporator, and the gas collection chamber is communicated with the gas outlet of the evaporator. The utility model has the advantages of utilize the high-efficient heat transmission ability of flat loop heat pipe to the high thermal conductivity of full play heat sink can show and reduce local hot temperature, has solved the problem that current heat dissipation scheme is difficult to eliminate the electronic component focus, is suitable for the radiating application scenario of high heat flux density device that has local focus.

Description

Loop heat pipe evaporator with composite heat sink and loop heat pipe system

Technical Field

The utility model belongs to the technical field of the heat dissipation, specificly relate to a compound heat sink's loop heat pipe evaporimeter and loop heat pipe system.

Background

The loop heat pipe utilizes the phase change of the working medium to transfer heat, can effectively enlarge a heat dissipation surface, solves the heat dissipation problem of a high-power device, and has the advantages of good heat transfer performance, light weight and compact structure. With the gradual development and maturity of the technology, the loop heat pipe has wide application in the aspects of heat dissipation in the fields of high heat flux density electronic devices, aerospace, aviation and the like.

The loop heat pipe structurally divides an evaporation section and a condensation section of a traditional heat pipe into an evaporator and a condenser, and is connected by a gas-liquid pipeline to form a closed loop. The process of latent heat absorption by evaporation of the working medium, latent heat release by condensation and flow of the working medium is utilized to carry out long-distance heat transfer, the heat transfer capacity is large, and the heat dissipation efficiency is high.

With the development of integration and miniaturization of electronic components, the thermal problem on the electronic components is more and more serious, the uneven distribution condition of the surface temperature of the electronic components is more and more obvious, the local hot spot phenomenon on the surface of the electronic components is prominent, and the local high temperature can seriously affect the working performance and reliability of the electronic components. The conventional loop heat pipe has difficulty in improving the local hot spot of the electronic component, so that further improvement on the existing heat dissipation technology is needed to obtain more excellent heat dissipation capacity and heat uniformity, thereby solving the local hot spot problem when the electronic component is cooled.

SUMMERY OF THE UTILITY MODEL

The technical problem is as follows: not enough to current heat dissipation technology existence, the utility model aims at providing a compound heat sink's loop heat pipe evaporimeter and loop heat pipe system, it can solve the uneven problem of electronic component surface temperature distribution, reduces its surface temperature gradient, can effectively avoid electronic component to break down or become invalid because of local high temperature.

The technical scheme is as follows: in order to realize the purpose of the utility model, the utility model provides a loop heat pipe evaporator of composite heat sink, which comprises an evaporator shell, a liquid storage cavity, a gas collection chamber, a liquid absorption core and a heat sink; the evaporator shell is of a flat plate type cavity structure, working media are filled in the evaporator shell, the left side wall and the right side wall of the evaporator shell are respectively provided with an evaporator liquid inlet and an evaporator gas outlet, and the outer wall surface of the bottom of the evaporator shell is bonded with the heat sink; the heat sink is of a sheet-like structure; the liquid suction core is a whole and is arranged inside the cavity of the evaporator shell, the cavity inside the evaporator is separated into two cavities, namely the liquid storage cavity and the gas collection chamber, the liquid storage cavity is communicated with the liquid inlet of the evaporator, and the gas collection chamber is communicated with the gas outlet of the evaporator.

Wherein: the evaporator shell is made of copper, aluminum and alloy thereof or stainless steel, and the shell thickness is 1.5-3.5 mm.

The heat sink is made of a material with high thermal conductivity coefficient, the plane thermal conductivity coefficient is 500-2000W/(m.K), and the thickness of the heat sink is 0.05-0.6 mm.

One surface of the heat sink is bonded with the outer wall surface of the bottom of the evaporator, the other surface of the heat sink is bonded with a heat source, and the bonding agents are all heat-conducting silica gel.

The lower surface of the liquid suction core is provided with a plurality of steam channels, and the steam channels are communicated with the gas collection chamber.

The liquid absorption core is made of one of copper, nickel or alloys thereof, the thickness of the liquid absorption core is 4-6 mm, and the porosity of the liquid absorption core is 0.4-0.6.

The liquid absorption core is prepared by adopting a sintering method and a pressurizing foaming method.

Preferably, the width of the steam channels is equal, and the distance between the steam channels is equal and is 1.5-2 mm respectively.

Preferably, the inner surface of the evaporator shell forming the liquid storage cavity is provided with a heat insulating material coating, the thickness of the heat insulating material coating is 0.1-0.2 mm, and the heat insulating material coating can reduce the transmission of heat to the liquid working medium in the liquid storage cavity.

Preferably, the heat sink is made of high-thermal-conductivity graphite, the material is anisotropic, the in-plane thermal conductivity is more than or equal to 1000W/(m.K), the specific gravity is 1.0-1.3, the transverse heat transfer can be effectively carried out on the heat with uneven distribution on the surface of the heat source, the heat soaking effect is achieved, and the cost is low.

Preferably, the working medium is water, methanol, liquid ammonia or acetone.

The loop heat pipe system comprises the evaporator, the condenser, a liquid pipeline and a gas pipeline, wherein the condenser comprises a gas inlet and a liquid outlet, the liquid pipeline is communicated with the liquid outlet and a liquid storage cavity, and the gas pipeline is communicated with the gas inlet and a gas collecting chamber.

Has the advantages that: compared with the prior art, the technical scheme of the utility model have following advantage:

the utility model discloses a flat plate type evaporimeter, its flat plate structure can be directly with electronic component surface in close contact with, has effectively reduced thermal contact resistance to strengthen heat transfer effect, and the temperature gradient of flat plate type evaporimeter and the velocity gradient contained angle that working medium flows are less, and from the field angle of coordination, flat loop heat pipe has more excellent heat transfer performance than cylinder type loop heat pipe. In addition, the heat sink is bonded on the outer wall surface of the bottom of the evaporator, so that the transverse transfer of heat on the surface of the heat source can be enhanced, high heat gathered at a hot spot can be transversely transferred to the surrounding area, the temperature of the local hot spot of the heat source is reduced, the heat dissipation is more uniform, the effect of eliminating the hot spot on the surface of the heat source is achieved, and the performance reduction and the failure of the electronic element caused by overhigh local temperature are avoided; and the thickness of the heat sink is ultra-thin, so that the device can be suitable for heat dissipation of compact electronic components. And the evaporator and the condenser of the whole loop heat pipe device are separately arranged, so that the condenser can be placed outside the data machine room, heat can be directly transferred to the environment outside the data machine room, and the cold load of the inner space of the data center can be effectively reduced. The utility model discloses have excellent transverse heat transfer performance, can play fine effect to the evenly distributed of heat source surface heat for its surface temperature is even, utilizes the circulation of working medium in whole loop heat pipe to heat transfer to the environment with the heat source simultaneously, has both guaranteed to reduce heat source temperature, can reduce heat source surface temperature gradient again.

Drawings

Fig. 1 is a schematic structural diagram of a loop heat pipe system of a composite heat sink;

fig. 2 is a schematic diagram of an internal structure of a loop heat pipe evaporator of a composite heat sink according to a first embodiment of the present invention;

figure 3 is a schematic diagram of the structure of a wick according to a first embodiment of the present invention;

fig. 4 is a schematic view of the contact surface of the gas collection chamber, the liquid storage chamber and the liquid absorption core provided by the first embodiment of the invention;

fig. 5 is a schematic diagram of an internal structure of a loop heat pipe evaporator of a composite heat sink according to a second embodiment of the present invention;

figure 6 is a schematic diagram of the structure of a wick according to a second embodiment of the present invention;

fig. 7 is a schematic view of the contact surface of the gas collection chamber, the liquid storage chamber and the liquid absorption core provided by the second embodiment of the invention;

the reference numbers are schematic: 1. an evaporator; 2. a liquid line; 3 a gas pipeline; 4, a condenser; 5. a heat sink; 6. an evaporator air outlet; 7. a liquid inlet of the evaporator; 8. an evaporator housing; 9. a gas collection chamber; 10. a wick; 11. a steam channel; 12. a liquid storage cavity; 13. an air inlet; 14. and a liquid outlet.

Detailed Description

The technical solution of the present invention will be further explained with reference to the accompanying drawings and specific implementation methods.

The utility model provides a loop heat pipe evaporator of composite heat sink, the structure of which is shown in figure 2, comprising an evaporator shell 8, a gas collection chamber 9, a liquid storage cavity 12, a liquid absorption core 10 and a heat sink 5; the evaporator shell 8 is of a flat plate type cavity structure, working media are filled in the evaporator shell, the left side wall and the right side wall of the evaporator shell are respectively provided with an evaporator liquid inlet 7 and an evaporator gas outlet 6, and the outer wall surface of the bottom of the evaporator shell is bonded with the heat sink 5; the heat sink 5 is of a sheet-like structure; the liquid absorption core 10 is an integral body and is arranged in the middle of the cavity of the evaporator shell 8, and two cavities are formed between the liquid absorption core and the evaporator shell 8, namely the gas collection chamber 9 and the liquid storage cavity 12, the gas collection chamber 9 is communicated with the air outlet 6 of the evaporator, and the liquid storage cavity 12 is communicated with the liquid inlet 7 of the evaporator; the lower surface of the liquid absorbing core 10 is provided with a plurality of steam grooves 11, and the steam grooves 11 are communicated with the gas collecting chamber 9.

Furthermore, the utility model discloses still provide a loop heat pipe system, package above-mentioned evaporimeter 1, condenser 4, liquid pipeline 2, gas line 3, the condenser includes air inlet 13 and liquid outlet 14, liquid pipeline 2 connects liquid outlet 14 and evaporimeter inlet 7, and gas line 3 connects air inlet 13 and evaporimeter gas outlet 6 to with entire system intercommunication, constitute the circulation circuit that can supply the working medium to flow.

The working process and principle of the loop heat pipe system are as follows: when the electronic element works, the outer surface of the electronic element radiates unevenly, heat is firstly conducted to the wall surface of the evaporator by the heat sink 5, and the heat is quickly and transversely conducted when passing through the heat sink 5 due to the high local radiation quantity of the surface of the electronic element, so that the heat transmitted to all parts of the wall surface of the evaporator is uniform. Then, the liquid in the liquid absorption core 10 in the evaporator is evaporated and vaporized, the steam working medium enters the steam channel 11 and then is collected in the gas collecting chamber, flows into the gas pipeline 3 under a small pressure difference, releases heat after reaching the condenser 4 and is condensed into liquid, and the liquid working medium flows back to the evaporator 1 through the liquid pipeline 2. The circulation is carried out, the heat dissipation and cooling are carried out on the electronic element, and the local hot spot on the surface of the electronic element is eliminated.

The heat transfer process during the operation of the loop heat pipe system specifically comprises the following parts: the unevenly distributed heat is uniformly transferred to the wall surface of the evaporator from the heat source through the heat sink 5; then the liquid is transmitted to a liquid-gas interface in the evaporator 1 through the wall surface of the evaporator and a liquid absorption core 10 filled with working medium; the liquid evaporates at the liquid-vapor interface of the evaporator 1; the vapor in the vapor collection chamber flows from the evaporator 1 to the condenser 4; the steam condenses on the liquid-gas interface inside the condenser 4; heat is transferred to the cold source from the wall surface of the condenser 4; the condensed working liquid is refluxed to the evaporator 1.

Example 1:

as shown in fig. 2, two cavities, namely a gas collection chamber 9 and a liquid storage chamber 12, are formed between a liquid absorption core 10 and an evaporator shell 8 in the evaporator, the two cavities are positioned at the left side and the right side of the liquid absorption core 10, the liquid absorption core 10 and the evaporator shell 8 are tightly connected through a vacuum sintering or high-temperature melting method, and a heat insulation material coating is arranged on the inner surface of the evaporator shell 8 forming the liquid storage chamber 12, so that heat leakage towards the liquid storage chamber 12 through the wall of the evaporator can be reduced. The evaporator with the structure has small thickness, is convenient to install in IT equipment with narrow space and limited height, and can dissipate heat of electronic elements.

Example 2:

as shown in fig. 5, the difference from embodiment 1 lies in that the liquid storage cavity 12 is disposed above the wick 10, and this structure has the advantages that under the dual driving of gravity and capillary force, the working medium can more favorably flow back to the wick 10, and the wick prevents the liquid storage cavity 12 from directly contacting the bottom surface of the evaporator, so that leakage of heat generated by the heat source to the liquid storage cavity 12 can be effectively reduced, and it is ensured that the liquid storage cavity 12 can supply sufficient liquid to the wick 10, and the loop heat pipe can stably operate for a long time.

Claims

1. A loop heat pipe evaporator of a composite heat sink is characterized in that the evaporator comprises an evaporator shell (8), a gas collection chamber (9), a liquid storage cavity (12), a liquid absorption core (10) and a heat sink (5); the evaporator shell (8) is of a flat plate type cavity structure, working media are filled in the evaporator shell, the left side wall and the right side wall of the evaporator shell are respectively provided with an evaporator liquid inlet (7) and an evaporator gas outlet (6), and the outer wall surface of the bottom of the evaporator shell is provided with the heat sink (5); the heat sink (5) is of a sheet-like structure; wick (10) set up in the inside cavity of evaporimeter shell (8) to constitute two cavitys with the inside cavity of evaporimeter shell (8), promptly collection chamber (9) with stock solution chamber (12), and collection chamber (9) and evaporimeter gas outlet (6) intercommunication, stock solution chamber (12) and evaporimeter inlet (7) intercommunication.

2. The loop heat pipe evaporator of the composite heat sink as recited in claim 1, wherein the evaporator shell (8) is made of copper, aluminum and its alloy or stainless steel, and the shell thickness is 1.5-3.5 mm.

3. The loop heat pipe evaporator of the composite heat sink as recited in claim 1, wherein the planar thermal conductivity of the heat sink (5) is 500-2000W/(m.K), and the thickness thereof is 0.05-0.6 mm.

4. The loop heat pipe evaporator of composite heat sink as recited in claim 1, characterized in that one face of said heat sink (5) is bonded to the bottom outer wall face of the evaporator shell (8).

5. The loop heat pipe evaporator of composite heat sink according to claim 1, wherein the lower surface of the wick (10) has a number of vapor channels (11), and the vapor channels (11) are communicated with the gas collection chamber (9).

6. The loop heat pipe evaporator of the composite heat sink as recited in claim 1, characterized in that the inner surface of the evaporator shell (8) contacting the liquid storage cavity (12) is provided with a coating of heat insulating material with a thickness of 0.1-0.2 mm.

7. The loop heat pipe evaporator of composite heat sink of claim 1, wherein the working medium is any one of water, methanol, liquid ammonia or acetone.

8. The loop heat pipe evaporator of any composite heat sink of claims 1-7, wherein the loop heat pipe system comprises the evaporator, a condenser (4), a liquid pipeline (2) and a gas pipeline (3), and an air inlet (13) and an air outlet (14) are installed at two ends of the condenser (4); the liquid pipeline (2) is connected with the liquid outlet (14) and the evaporator liquid inlet (7), and the gas pipeline (3) is connected with the gas inlet (13) and the evaporator gas outlet (6).