VAPOR CHAMBER BASED ON FLAT PLATE LOOP HEAT PIPE

Abstract

The present disclosure discloses a vapor chamber based on a flat plate loop heat pipe. The flat plate loop heat pipe composed of an evaporator, a reservoir and a gas/liquid line is pre-buried in an aluminum alloy plate, so as to form the vapor chamber based on the flat plate loop heat pipe. The evaporator of the flat plate loop heat pipe is arranged in a region, attached to a biggest heat source of a chip to be subjected to heat dissipation, on the vapor chamber, and the side, provided with a vapor channel, of the evaporator is attached to the biggest heat source.

Description

FIELD

The present disclosure relates to a vapor chamber, and more particularly, to a vapor chamber based on a flat plate loop heat pipe, and belongs to the technical field of electronic equipment heat dissipation.

BACKGROUND

A loop heat pipe is high-efficiency two-phase heat transfer equipment, and has the characteristics of high heat transfer performance, long-distance heat transfer, good temperature control, bending arbitrariness, convenience in installation, etc. Due to many advantages beyond comparison over other types of heat transfer equipment, the loop heat pipe has a very broad application prospect in many fields such as aviation, aerospace and ground electronic equipment heat dissipation.

As shown in FIG. 1, the loop heat pipe mainly includes an evaporator 1, a condenser 2, a reservoir 3, a vapor line 4 and a liquid line 5. The whole cycle is as follows: liquid is evaporated on the outer surface of a capillary wick 6 in the evaporator 1, and absorbs heat outside the evaporator 1, and then generates vapor flows from the vapor line 4 to the condenser 2, and releases the heat in the condenser 2 to a heat sink, so as to condense the vapor into liquid, and finally the liquid flows into the reservoir 3 through the liquid line 5. A liquid working fluid in the reservoir 3 is maintained being supplied to the capillary wick in the evaporator 1.

Because of the small space required for installation of a flat plate loop heat pipe, and the convenience of installing a flat plate evaporator and a heat source plane, it has been a research hotspot and a key application direction in recent years. Based on structures, flat plate loop heat pipes mainly fall into two forms. The first form is a disc-shaped flat plate loop heat pipe, where the evaporator is in a disc shape, and the evaporator and the reservoir are separated by a capillary wick. The second form is a rectangular flat plate loop heat pipe, where the reservoir is arranged on one side of the evaporator.

A Vapor Chamber (VC) usually adopts a flat plate structure provided with a capillary wick. After the VC is filled with a working fluid, temperature equalization is realized through a gas-liquid phase change of the working fluid. When the VC is used, heat sources (a chip or equipment) is attached to the VC, and heat conductive filler is used in the installation interface. There are mainly two application forms:

1) a heat conductive VC: heat of one or more heat sources is conducted to one side or two sides (heat sink attached region as shown in FIG. 2) of a heat spreading plate, and then the heat is carried away in other heat dissipation modes (water cooling, heat conduction and the like), as shown in FIG. 2; and

(2) a heat spreading VC: heat of one or more heat sources is uniformly spread into other non-heat source regions of the whole VC to play a temperature equalization role and enlarge the heat dissipation area, and then the heat is carried away in other heat dissipation modes such as air cooling or heat conduction, as shown in FIG. 3.

However, the application of the VC has the following issues: there is a conflict between improvement of the product properties and the requirement for the capillary wick. On the one hand, in order to improve certain properties, it is desired that the capillary diameter is as small as possible, because reducing of the capillary diameter of the capillary wick can improve the maximum heat transfer capability, increase the maximum heat flux, improve the anti-overload and anti-gravity working capability and increase the size of the VC. On the other hand, in order to improve part of the properties, it is required that the capillary wick obtains a relatively high permeability by using a relatively large diameter and then increases the size of the VC, that is, increases the length of the flow, so the flowing resistance needs to be reduced, or decreases the thickness of the VC, that is, decreases the flowing sectional area, so the flowing resistance needs to be reduced.

SUMMARY

In view of the above, the present disclosure provides a vapor chamber based on a flat plate loop heat pipe, so as to improve the heat transfer capability, the maximum heat flux and the anti-overload and anti-gravity working capability of the vapor chamber, increase the size of a heat spreading plate and decrease the thickness of the vapor chamber, and solve a conflicting requirement between the improvement of the properties of the vapor chamber and the diameter of the capillary wick.

In the vapor chamber based on the flat plate loop heat pipe, the vapor chamber is attached to heat sources, and includes: a heat spreading plate and a flat plate loop heat pipe composed of an evaporator, a reservoir and a gas/liquid line. The flat plate loop heat pipe is pre-buried in the heat spreading plate. The evaporator is arranged on the heat spreading plate at the position of attachment to the biggest heat source in the heat sources. The reservoir is used to supply liquid to the evaporator. Positions on the heat spreading plate that are attached to other heat sources except the biggest heat source in the heat sources are used as “heat source attached regions”, and positions on the heat spreading plate that are not attached to the heat sources, are used as “heat sink attached regions”. The gas/liquid line leading out from an outlet of the evaporator is disposed in a meandering fashion between the “heat source attached regions” and the “heat sink attached regions” on the heat spreading plate, so that a liquid working fluid enters the “heat sink attached regions” after absorbing heat of the “heat source attached regions” and being evaporated into vapor, and a gas working fluid releases heat in the “heat sink attached regions” and is condensed into liquid; and circulation is performed hereby, and the working fluid finally flows back into the reservoir after being condensed by the “heat sink attached regions” into liquid, thereby forming a loop.

As a preferable implementation of the present invention, cold sources are arranged in the “heat sink attached regions” on one side or two sides of the heat spreading plate. The gas/liquid line led out from the outlet of the evaporator is disposed in a meandering fashion between the “heat sink attached regions” and the “heat source attached regions” on the heat spreading plate.

As a preferable implementation of the present invention, the reservoir is suspended, and is not connected with the heat spreading plate in a heat conduction manner.

As a preferable implementation of the present invention, the evaporator is exposed and directly attached to the biggest heat source in the heat sources.

As a preferable implementation of the present invention, the gas/liquid line is firstly formed by a copper, stainless steel or titanium alloy pipeline sheet metal, and then pre-buried in the heat spreading plate in a gluing or welding manner.

Beneficial effects.

(1) The flat plate loop heat pipe may use a small-diameter capillary wick to provide higher capillary force, and external loops are all bare pipes without capillary wicks, so that the flowing resistance is low; and finally the heat transfer capability, the maximum heat flux heat dissipation capability and the anti-overload and anti-gravity working capability of the vapor chamber may be improved, the size of the heat spreading plate may be increased, and the thickness of the vapor chamber may be decreased.

(2) Compared with a traditional vapor chamber structure, the vapor chamber of the present disclosure has the advantages that the thickness of the vapor chamber is decreased by downsizing the evaporator and the line of the flat plate loop heat pipe, so as to satisfy an application occasion with a smaller installation space.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a structural schematic diagram of a loop heat pipe;

FIG. 2 is a heat conduction schematic diagram of a heat conductive vapor chamber;

FIG. 3 is a heat conduction schematic diagram of a heat spreading vapor chamber;

FIGS. 4 and 5 are heat conduction schematic diagrams of a heat conductive vapor chamber based on a flat plate loop heat pipe; and

FIGS. 6 and 7 are heat conduction schematic diagrams of a heat spreading vapor chamber based on a flat plate loop heat pipe.

In the drawings, 1: evaporator; 2: condenser; 3: reservoir; 4: vapor line; 5: liquid line; 6: capillary wick; and 7: gas/liquid line

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present disclosure is described in detail below in combination with accompanying drawings and embodiments.

The present embodiment provides a vapor chamber based on a flat plate loop heat pipe, which may solve a conflicting requirement of the improvement of the properties of the vapor chamber for the diameter of a capillary wick.

Embodiment 1: Heat Conductive Vapor Chamber

As shown in FIGS. 4 and 5, a flat plate loop heat pipe composed of an evaporator, a reservoir and a gas/liquid line is pre-buried in an aluminum alloy heat spreading plate in a gluing or welding manner to form a vapor chamber based on the flat plate loop heat pipe. The vapor chamber is attached to a circuit board to be subjected to heat dissipation, so that the evaporator of the flat plate loop heat pipe is arranged in a region, attached to a biggest heat source (namely a position with the greatest heat generation amount of the circuit board) of the circuit board, on the vapor chamber. The side, provided with a vapor channel, of the evaporator is attached to the biggest heat source. The evaporator may be pre-buried into the aluminum alloy heat spreading plate, or is only fixed in the aluminum alloy heat spreading plate. The evaporator is exposed and directly attached to the biggest heat source. The liquid reservoir of the flat plate loop heat pipe is suspended, and is not connected with the aluminum alloy heat spreading plate in a heat conduction manner, so as to prevent heat leakage to the reservoir. “Heat sink attached regions” and “heat source attached regions” are arranged on the vapor chamber. The “heat source attached regions” are regions attached to heat sources (except the biggest heat source) on the circuit board, and the “heat sink attached regions” are regions adopting a cooling mode (cold sources) on the back surface of the vapor chamber, as shown in FIG. 5. The gas/liquid line led out from an outlet of the evaporator is disposed in a meandering manner between the “heat sink attached regions” and the “heat source attached regions” on the vapor chamber. The gas/liquid line finally passes through the “heat sink attached regions” and then returns to the reservoir of the flat plate loop heat pipe, as shown in FIG. 4. The gas/liquid line may be first formed by a copper, stainless steel or titanium alloy pipeline sheet metal, and then pre-buried in the aluminum alloy heat spreading plate in a gluing or welding manner.

Working principle: since the evaporator of the flat plate loop heat pipe is attached to the biggest heat source, liquid is evaporated into vapor in the evaporator, and the vapor flows to the “heat sink attached regions” and releases heat, and then is condensed into liquid. Since the gas/liquid line is disposed in a meandering fashion between the “heat source attached regions” and the “heat sink attached regions”, a liquid working fluid absorbs heat in the “heat source attached regions” and then is evaporated into vapor, and the vapor releases heat in the “heat sink attached regions” and then is condensed into liquid. This cycle is performed for multiple times, and finally the working fluid flows back into the reservoir after being condensed by the “heat sink attached regions” into the liquid. In such cycle operation, a function of conducting the heat of one or more heat sources to the “heat sink attached regions” is realized.

Embodiment 2: Heat Spreading Vapor Chamber

A main difference of the heat spreading vapor chamber from the heat conductive vapor chamber is that: except “heat source attached regions” on the vapor chamber, other regions in no contact with heat sources are all used as “heat sink attached regions”. Therefore, a gas/liquid line is disposed in a meandering fashion between the “heat source attached regions” and other regions. The working principle of the heat spreading vapor chamber is the same as that of the heat conductive vapor chamber.

The above contents are merely preferred embodiments of the present invention, but not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. that are made without departing from the spirit and principle of the present disclosure shall all fall within the protection scope of the present disclosure.

Claims

1. A vapor chamber based on a flat plate loop heat pipe, wherein the vapor chamber is attached to heat sources, comprising: a heat spreading plate; anda flat plate loop heat pipe composed of an evaporator, a reservoir and a gas/liquid line;wherein the flat plate loop heat pipe is pre-buried in the heat spreading plate; wherein the evaporator is arranged on the heat spreading plate at the position of attachment to the biggest heat source in the heat sources; wherein the reservoir is used to supply liquid to the evaporator; positions on the heat spreading plate that are attached to other heat sources except the biggest heat source in the heat sources are used as “heat source attached regions”, and positions on the heat spreading plate that are not attached to the heat sources are used as “heat sink attached regions”; wherein the gas/liquid line leading out from an outlet of the evaporator is disposed in a meandering fashion between the “heat source attached regions” and the “heat sink attached regions” on the heat spreading plate, so that a liquid working fluid enters the “heat sink attached regions” after absorbing heat of the “heat source attached regions” and being evaporated into vapor, and a gas working fluid releases heat in the “heat sink attached regions” and is condensed into liquid; and circulation is performed hereby, and the working fluid finally flows back into the reservoir after being condensed by the “heat sink attached regions” into liquid, thus forming a loop.

2. The vapor chamber based on the flat plate loop heat pipe according to claim 1, wherein cold sources are arranged in the “heat sink attached regions” on one side or two sides of the heat spreading plate; and the gas/liquid line leading out from the outlet of the evaporator is disposed in a meandering fashion between the “heat sink attached regions” and the “heat source attached regions” on the heat spreading plate.

3. The vapor chamber based on the flat plate loop heat pipe according to claim 1, wherein the liquid reservoir is suspended, and is not connected with the heat spreading plate in a heat conduction manner.

4. The vapor chamber based on the flat plate loop heat pipe according to claim 1, wherein the evaporator is exposed and directly attached to the biggest heat source in the heat sources.

5. The vapor chamber based on the flat plate loop heat pipe according to claim 1, wherein the gas/liquid line is formed by a copper, stainless steel or titanium alloy pipeline sheet metal, and pre-buried in the heat spreading plate in a gluing or welding manner.

6. The vapor chamber based on the flat plate loop heat pipe according to claim 1, wherein the heat spreading plate is an aluminum alloy plate.

7. The vapor chamber based on the flat plate loop heat pipe according to claim 2, wherein the liquid reservoir is suspended, and is not connected with the heat spreading plate in a heat conduction manner.

8. The vapor chamber based on the flat plate loop heat pipe according to claim 2, wherein the evaporator is exposed and directly attached to the biggest heat source in the heat sources.

9. The vapor chamber based on the flat plate loop heat pipe according to claim 2, wherein the gas/liquid line is formed by a copper, stainless steel or titanium alloy pipeline sheet metal, and pre-buried in the heat spreading plate in a gluing or welding manner.

10. The vapor chamber based on the flat plate loop heat pipe according to claim 2, wherein the heat spreading plate is an aluminum alloy plate.