CN1705043B

CN1705043B - Method for improving flow property of working fluid in liquid-vapor phase heat dissipation device

Info

Publication number: CN1705043B
Application number: CN 200410042853
Authority: CN
Inventors: 叶岚凯; 林哲玮; 林绍文; 徐金城; 蔡明杰
Original assignee: Industrial Technology Research Institute ITRI
Current assignee: Industrial Technology Research Institute ITRI
Priority date: 2004-05-26
Filing date: 2004-05-26
Publication date: 2010-06-23
Anticipated expiration: 2024-05-26
Also published as: CN1705043A

Abstract

The present invention discloses a method for improving the flow properties of a working fluid inside a liquid-vapor phase heat dissipation device. The method can be applied to the liquid-vapor phase heat dissipation device to improve the flow properties of the internal working fluid, thereby improving the heat dissipation capacity of the heat dissipation device. The present invention covers a layer of surface modification material on the surface of a capillary structure in the device that can increase the bonding force between the working fluid and the capillary structure, thereby reducing the contact angle between the working fluid and the capillary structure, and thus the working fluid has a higher fluidity, thereby solving the problem of high heat flux density of the liquid-vapor phase heat dissipation device and increasing the heat dissipation efficiency. The method can be applied not only to heat-generating electronic components in a limited space, but also to other electronic components that need to maintain a constant temperature.

Description

Improve the method for the flowing property of liquid vapour phase heat sink interior working fluid

Technical field

The present invention relates to a kind of method of making liquid vapour phase heat abstractor, particularly a kind of method that improves the flowing property of liquid vapour phase heat sink interior working fluid.

Background technology

For satisfying high-performance, high efficiency requirement, the operating frequency of electronic component improves constantly, thereby cause caloric value to increase day by day, the raising of science and technology simultaneously makes electronic product more compact, and the reduction of volume makes the included electronic component number of unit volume increase relatively, thereby cause high hot flux density, and the operating temperature of electronic component and its reliability, life-spans etc. are closely bound up, therefore, how to improve effectively and dispelled the heat into a critical problem, the field that especially is applied to the peripheral product of the limited electronics such as mobile computer of volume is all the more so.

Difference because of the design of electronic component usefulness, make in electronic product heat flux distribution inequality everywhere, and because the local temperature difference can form so-called focus (hotspot) from the teeth outwards, for addressing this problem, developed a kind of soakage device with capillary structure, as alleged heat pipe (Heat pipe), its operating principle is to inject volatile working fluid such as water or alcohol etc. in an airtight container, or in this closed container, form the state of a low pressure, and portion is provided with capillary structure within it, working fluid is converted to vapour phase after heat side absorbs heat energy, the working fluid of vapour phase is condensed into liquid state again in a side of lower temperature, high latent heat effect by vapour-liquid phase transformation process is discharged heat, and condense into liquid working fluid, flow back to heat side by capillary structure again, form a kind of heat radiation operation of circulation like this.

See also Fig. 1, be the cross-section structure of the liquid vapour phase heat abstractor of prior art, it is the airtight cavity 10 of a metal, in a capillary structure layer 11 is arranged; The heating end (evaporation ends) of the airtight cavity 10 of metal is 12, cold junction (condensation end) is 13; The airtight cavity 10 of metal includes working fluid, and working fluid can absorb the fluid of a large amount of heats when can be in pure water, ammoniacal liquor, methyl alcohol, ethanol and the acetone any mobile high and evaporation; Its radiating principle is by working fluid heat energy direction shown in arrow among Fig. 1 that electronic component produces to be transmitted, and by heating end 12 heat is sent to cold junction 13, utilizes that capillary structure layer 11 in the airtight cavity 10 of metal are evaporated, the circulation of condensation.

At present, have in the soakage device of capillary structure, though capillary structure can provide the flowability of liquid, but its capillary pulling power is relevant with the contact and the performance character of material on surface, with water is example, and for than the hydrophilic surface of tool, its surface contact angle is less and have a preferable flowability, therefore, it is also better that capillary pulling power that can provide and liquid replenish the performance that refluxes.

For general liquid vapour phase heat abstractor, to adopt water is that working fluid is an example, because need having the preferable coefficient of heat conduction, the material that device itself is adopted just can make radiating effect preferable, and the metal that at present mainly has a preferable hot biography ability with copper or aluminium etc. is a base material, but copper is because of being easy to and air produces cupric oxide, and aluminium then generates aluminium oxide, and causes the contact angle of the inwall of device capillary structure and water excessive, the mobile of water reduced relatively, therefore reduced heat dissipation; And if otherwise improve capillary pulling power, as change the size of capillary structure or remove surface impurity etc., because of the cost of required manufacturing technology of the size that changes capillary structure and cost higher, even and if the size of capillary structure reaches required size, the contact angle of capillary surface and water is diminished, but, therefore thoroughly do not improve the flowing property of working fluid because the surface substrate character of capillary structure is not improved yet.

Now when making heat pipe etc. and include the soakage device of working fluid, if select copper for use is the material of heat pipe, its step needs copper pipe is cleaned earlier, to reduce the pollution of impurity, and then guarantee its usefulness, yet general cleaning step often need expend a large amount of manpowers, and if clean with relevant chemical agent, as when using pickling or organic solvent etc. to clean, not only increase its cost, but also can environment be polluted, the most important thing is, it is bad that it cleans the back anti-aging capability, in case after the oxidation, the flowability of working fluid will reduce once again.

The heat dissipation element with capillary structure of prior art, capillary structure design aspect at water conservancy diversion, except the size and arrangement of capillary structure design, its surface nature for capillary structure there is no and significantly improves, as No. the 6th, 158,502, United States Patent (USP) of announcing on December 12nd, 2000 and the United States Patent (USP) of announcing January 2 calendar year 2001 the 6th, 167, No. 948.

The TaiWan, China Patent publish multiple heat abstractor with capillary structure, as No. the 563016th, the TaiWan, China patent of on November 21st, 2003 bulletin, it has disclosed a kind of method of making the hot-fluid conduit; In addition as No. the 528151st, the TaiWan, China patent of on April 11st, 2003 bulletin, then be to change the individual layer capillary structure into double-deck capillary structure; Also have one as on September 1st, 2002 bulletin No. the 501722nd, TaiWan, China patent, its explanation is made up its capillary structure with multi-form copper mesh; All do not mention the contact property that how to improve working fluid and capillary structure surface in the below disclosed patented technology.

Summary of the invention

Main purpose of the present invention is to improve the flowing property of liquid vapour phase heat sink interior working fluid, and then improves the heat-sinking capability of heat abstractor.

For reaching this purpose, the mode of the present invention by surfaction improved the liquid vapour phase heat abstractor of prior art, it mainly is capillary structure surface coverage (coating) layer of material in device, coverage mode can be sputter (sputting), plating (plating), electroplate (electroplating), electroforming (electronform), vapour deposition (CVD) etc., the material that covers can be copper, iron, zinc, aluminium, nickel, with in the chromium any, make the contact angle on working fluid and capillary structure surface little than prior art, therefore the capillary structure in working fluid and the airtight cavity has preferable adhesion, thereby make the flowability of fluid better, and then make the better effects if of heat radiation.

Description of drawings

Fig. 1 is the cross-section structure of the liquid vapour phase heat abstractor of prior art;

Fig. 2 is the cross-section structure according to liquid vapour phase heat abstractor of the present invention;

When Fig. 3 does not clean capillary structure layer surperficial for the liquid vapour phase heat abstractor of prior art, the figure of water and capillary structure layer contact angle;

Fig. 4 is after the liquid vapour phase heat abstractor of prior art cleans the surface of capillary structure layer, the figure of water and capillary structure layer contact angle;

Fig. 5 be according to the present invention behind surface coverage one deck nickel of capillary structure layer, the figure of water and capillary structure layer contact angle;

Fig. 6 is the contact angle of working fluid and the graph of a relation of heat dissipation; And

The graph of a relation that Fig. 7 influences the hot biography value of capillary structure layer for the thickness that covers nickel dam.

The specific embodiment

Relevant detailed technology content of the present invention and better embodiment, existing accompanying drawings is as follows.

See also Fig. 2, cross-section structure for liquid vapour phase heat abstractor according to the present invention, it is the airtight cavity 20 of a metal, include capillary structure layer 21, and on the surface of capillary structure layer 21, cover one deck hydrophilic layer 24, the mode that covers can be sputter, plating, plating, electroforming, vapour deposition etc., but is not limited to aforesaid way; The material of this hydrophilic layer 24 can be any in iron, zinc, aluminium, nickel and the chromium; The heating end (evaporation ends) of the airtight cavity 20 of metal is 22, cold junction (condensation end) is 23; The airtight cavity 20 of metal includes working fluid, and working fluid can absorb the fluid of a large amount of heats when can be in pure water, ammoniacal liquor, methyl alcohol, ethanol and the acetone any mobile high and evaporation; Its radiating principle is by working fluid heat energy direction shown in arrow among Fig. 2 that electronic component produces to be transmitted, and by heating end 22 heat is sent to cold junction 23, utilizes that capillary structure layer 21 in the airtight cavity 20 of metal are evaporated, the circulation of condensation.

In existing liquid vapour phase heat abstractor, be that base material, water are working fluid with copper, if do not clean the surface of capillary structure layer 21, then the surface contact angle of water and capillary structure layer 21 is approximate 90 ° as shown in Figure 3; If after cleaning, then contact angle is reduced to about 37 ° as shown in Figure 4.

Method of the present invention covers one deck nickel as shown in Figure 5 on the surface 50 of capillary structure layer 21, thickness is between 5nm and 10 μ m; After the covering, the contact angle of water and hydrophilic layer 24 only is approximately 27 °, compare comparatively among the three minimum with the contact angle of capillary structure layer 21 with water among Fig. 3 and Fig. 4, and after the contact angle attenuating, can increase the flowability of water, improve capillary pulling power, the heat that water can be taken away improves, and promotes the usefulness of heat radiation.

Please consult 6 again, be the contact angle of working fluid and the graph of a relation of heat dissipation, to adopt nickel is that hydrophilic layer 24, working fluid are that water is example, when the material of heat abstractor is copper, if do not clean the surface of capillary structure layer 21, coordinate position in the corresponding figure is 60, and heat dissipation is the poorest, with the contact angle maximum of water; After the surface of capillary structure layer 21 was cleaned, the coordinate position in the corresponding figure then was 61, and with the contact angle reduction of water, heat dissipation also improves; After adopting design of the present invention, on the surface of the capillary structure layer 21 of copper sheet, increase by one when covering thin layer nickel, the coordinate position in the corresponding figure is 62, and the contact angle of water and capillary structure layer 21 be a minimum among the three, and heat dissipation is the best also.

Because the present invention needs to cover layer of material on the surface of the capillary structure layer 21 of heat abstractor, if the material of hydrophilic layer 24 is a copper with the material of nickel, heat abstractor itself, because of the heat biography value of the capillary structure layer 21 of copper better than nickel, after covering one deck nickel the surface heat biography value of capillary structure layer 21 is descended, but because of the thickness that the present invention covered only is several nm or several μ m, the therefore influence that causes and little; See also Fig. 7, be the thickness of covering nickel dam and the graph of a relation of the hot biography value of capillary structure layer, when not covering nickel dam, the heat biography value of capillary structure layer 21 is higher, coordinate position in the corresponding figure is 70, and behind the nickel dam that covers only several μ m, the heat biography value of capillary structure layer 21 slightly descends, coordinate position in the corresponding diagram is 71, and the decline of hot biography value only has an appointment 2.54%.

The above is the preferred embodiments of the present invention only, is not limited to the present invention, and for a person skilled in the art, the present invention can have various changes and variation.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within the claim scope of the present invention.

Claims

1. A method for improving the flow properties of the internal working fluid of a liquid-vapor heat dissipation device, applied to a liquid-vapor heat dissipation device comprising a capillary structure layer (21) and a working fluid in a metal closed cavity (20);

It is characterized by:

An evaporating end (22) and a condensing end (23) are included in the liquid-vapor heat dissipation device, and the capillary structure layer (21) is formed at the evaporating end (22) and the condensing end (23), and the A hydrophilic layer (24) is formed on the capillary structure layer (21), and the hydrophilic layer (24) is made of a material that can reduce the contact angle between the working fluid and the surface of the capillary structure layer (21), so that the The working fluid has a good binding force with the capillary structure layer (21), so as to improve the fluidity of the working fluid on the surface of the capillary structure layer (21), and the material of the hydrophilic layer (24) is selected from iron, zinc, Any of the group consisting of aluminum, nickel, and chromium.

2. The method for improving the flow properties of the working fluid inside the liquid-vapor heat dissipation device according to claim 1, characterized in that the hydrophilic layer (24) only covers the surface of the capillary structure layer (21).

3. The method for improving the flow properties of the internal working fluid of the liquid-vapor heat dissipation device according to claim 1, wherein the method for forming the hydrophilic layer (24) is to form the material on the surface of the liquid-vapor layer by sputtering. The surface of the capillary structure layer (21).

4. The method for improving the flow properties of the internal working fluid of a liquid-vapor heat dissipation device according to claim 1, characterized in that the method for forming the hydrophilic layer (24) is to form the material on the surface by plating. The surface of the capillary structure layer (21).

5. The method for improving the flow properties of the working fluid inside the liquid-vapor heat dissipation device according to claim 1, characterized in that the method of forming the hydrophilic layer (24) is to form the material on the capillary layer by electroplating. The surface of the structural layer (21).

6. The method for improving the flow properties of the internal working fluid of a liquid-vapor heat dissipation device according to claim 1, characterized in that the method for forming the hydrophilic layer (24) is to form the material on the surface by electroforming The surface of the capillary structure layer (21).

7. The method for improving the flow properties of the internal working fluid of a liquid-vapor heat dissipation device according to claim 1, characterized in that the method for forming the hydrophilic layer (24) is to form the material on the surface by vapor deposition. The surface of the capillary structure layer (21).

8. The method for improving the flow properties of the working fluid inside the liquid-vapor heat dissipation device according to claim 1, characterized in that the thickness of the hydrophilic layer (24) is between 10 μm and 5 nm.