CN101082468A - Gravity force type micro-chute flat-plate hot pipe with carbon nano-tube suspending liquid as working substance - Google Patents
Gravity force type micro-chute flat-plate hot pipe with carbon nano-tube suspending liquid as working substance Download PDFInfo
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- CN101082468A CN101082468A CN 200710043438 CN200710043438A CN101082468A CN 101082468 A CN101082468 A CN 101082468A CN 200710043438 CN200710043438 CN 200710043438 CN 200710043438 A CN200710043438 A CN 200710043438A CN 101082468 A CN101082468 A CN 101082468A
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Abstract
This invention relates to a sort of flat heat pipe of tiny conduit of the gravity type, its industrial material is the suspending liquid of carbon-nanometer pipe, there is full of the suspending liquid of carbon-nanometer pipe in the tiny conduit plat of the gravity type, the section of the tiny conduit is rectangle or triangle, there has the wind cooling set and the liquid cooling set in the upper end of the flat heat pipe. The element which needs radiating attaches in the lower end of the flat heat pipe of tiny conduit, it use the flat heat pipe of the gravity type makes the heat quantity of the element which needs radiating to pass to the upper end of the wind and the liquid. The best bound of the liquid-filled rate is 40-60%, the best consistency is 2%. Thin invention uses the character that the suspending liquid of carbon-nanometer pipe consolidate the heat transfer property of the flat heat pipe, it debases the thermal resistance of the heat pipe effectively, and increases the most radiating power consumption.
Description
Technical field
The present invention relates to a kind of flat-plate heat pipe, specifically relate to a kind of gravity-type micro-channel flat plate heat pipe that is working medium with new and effective enhanced heat exchange working medium-carbon nano tube suspension.Belong to augmentation of heat transfer and electronic devices and components cooling field,
Background technology
High frequency along with electronic device, developing rapidly and MEMS (MicroElectro-Mechanical System of high speed and integrated circuit technique, microelectromechanical systems) development of technology, and various electronic devices and equipment, as computer chip etc. to high-performance, miniaturization and microminiaturized trend development, the overall power density of electronic devices and components increases substantially and physical size is more and more littler, heat flow density also increases thereupon, the heat that produces in the time of these electronic devices and components can being worked in time also effectively distributes, and will directly influence the cost of electronic device, service behaviour and reliability.The temperature environment of high temperature will certainly influence the performance of electronic devices and components, and this just requires it is carried out thermal control more efficiently.Therefore, the heat dissipation problem that effectively solves electronic devices and components has become the key technology that current electronic devices and components and electronic equipment are made.
Heat pipe is considered to one of effective way that solves the electronic equipment dissipating heat problem.And gravity type flat heat pipe is as a kind of high-efficiency heat transfer device, utilize the latent heat of vaporization of working medium to transmit heat, it has simple in structure, stable and reliable operation and the big advantage of heat radiation power, the more important thing is with general tubular heat tube and compares, wall temperature is even, and heat transfer property is more superior.At present, use neat liquid as the microminiature conduit flat-plate heat pipe of working medium because of its microelectronic device cooling field extensively and important application prospects, more and more be subjected to researcher's attention.Research to this kind heat pipe has both at home and abroad obtained some practicality achievements.
In recent years, nanometer technology begins to be applied to hot pipe technique.Because nano particle has small-size effect, interfacial effect, quantum size effect and macro quanta tunnel effect, makes nano particle show specificity at aspects such as structure, photoelectricity, magnetics and chemical property.Along with developing rapidly of nanometer material science, some scholars have begun to attempt nano particle is mixed with fluid, make nano granule suspension, strengthen heat convection, have brought present flourish vital for the augmentation of heat transfer technology.
In the heat pipe cycle fluid, add each metalloid or metal oxide nanoparticles, the structure and the rerum natura of cycle fluid have been changed, strengthened internal energy transmittance process, increased the coefficient of heat transfer of nano-fluid, make the heter temperature field more even, heat exchange is more powerful.Therefore, nano-fluid (nanoparticle suspension) has wide application prospect as a kind of new enhanced heat-transfer working medium.But it is very restricted to strengthen amplitude with metal or metal oxide nano fluid as the resulting coefficient of heat transfer of the heat pipe of working medium.Be necessary to seek a kind of new more effective nano-fluid as working medium, make the performance of heat pipe obtain bigger lifting.
CNT (CNT) suspension is a kind of novel nano-fluid, and comparing with traditional nano-fluid has some unique advantages.Maximum characteristics are that the thermal conductivity factor of CNT itself is very big, reach the order of magnitude of 3000w/m.k.Therefore carbon nano tube suspension has than the better heat exchange property of general nano-fluid, and its augmentation of heat transfer characteristic is confirmed by many basic research.
So far still nobody proposes to adopt carbon nano tube suspension to strengthen the heat pipe heat exchanging performance as the working medium in the heat pipe.Use carbon nano tube suspension as the heat pipe of working medium having unique development potentiality aspect electronic equipments such as electronics, the microelectronic device cooling cooling field, have broad application prospects, also will produce important economic benefit and social benefit.
Summary of the invention
The objective of the invention is at the deficiencies in the prior art, providing a kind of is the gravity-type micro-channel flat plate heat pipe of working medium with the carbon nano tube suspension, improves the heat transfer property of flat-plate heat pipe.
For realizing this purpose, technical scheme of the present invention is to adopt the working medium of carbon nano tube suspension as flat-plate heat pipe, utilizes the evaporation boiling heat transfer performance of carbon nano tube suspension stiffened flat plate heat pipe, improves its maximum heat radiation power.The adopting heat pipes for heat transfer face is designed to the micro-channel heat-transfer area, evenly has the micro-channel of rectangle or triangular cross-sectional shape on the micro-channel heat-transfer area, to increase the contact area of heat-transfer area and working medium, plays the effect of enhanced heat exchange.
The concrete structure of gravity-type micro-channel flat plate heat pipe of the present invention is: evenly distributed being installed on the cryosurface of some fin that cryosurface is cooled off, the inner working medium of injecting of the evaporation cavity of cryosurface below is carbon nano tube suspension, best liquid filled ratio is the 40-60% of evaporation cavity volume, in this scope, filling amount heat exchanging characteristic does not have influence substantially.The bottom surface of evaporation cavity is the micro-channel heat-transfer area.Described carbon nano tube suspension is the mixed liquor of deionized water and CNT, and the mass concentration of CNT is 0.5-3wt% in the suspension.
Fin in the flat-plate heat pipe of the present invention on the cryosurface uses the heat radiation of fan method for air-cooling, also can be designed to water-cooling.During use, the element of needs heat radiations is attached to the lower end of micro-channel flat plate heat pipe,, the heat of the element of needs heat radiation is delivered in upper end wind, the liquid by the working medium carbon nano tube suspension in micro-channel heat-transfer area and the evaporation cavity.
When gravity-type micro-channel flat plate heat pipe of the present invention moves, under the low heat loads operating mode, move several minutes earlier, the CNT that is deposited in heat pipe evaporation cavity 3 bottoms is suspended again, can normally move.
CNT of the present invention generally can use CNT arbitrarily, comprises SWCN (SWNT) and multi-walled carbon nano-tubes (MWNT).
The present invention utilizes carbon nano tube suspension stiffened flat plate adopting heat pipes for heat transfer characteristic, and carbon nano tube suspension concentration has tangible influence to the heat transfer characteristic of gravity type flat heat pipe, all can obtain strengthening effect in mass concentration is the scope of 0.5-3wt%.
Pressure has tangible influence to the heat exchange reinforcement rate of the gravity type flat heat pipe of use multi-walled carbon nano-tubes suspension.Pressure is more little, and the heat exchange strengthening effect behind the employing suspension is good more.Enhanced type heat pipe of the present invention under low pressure (the heat pipe running temperature is lower than 80 degree) result of use is better.Pressure is by regulating the condensation strength control.
Among the present invention is the gravity-type micro-channel flat plate heat pipe of working medium with the carbon nano tube suspension, with before be that the flat-plate heat pipe of working medium is compared with the pure water, can very significant raising heat transfer characteristic, reduce the heat pipe thermal resistance, increase heat radiation power.The heat pipe thermal resistance can reduce about 40%～50%, and heat exchange power can improve about 1 times～1.7 times.
Description of drawings
Fig. 1 is the structural representation of gravity-type micro-channel flat plate heat pipe of the present invention.
Among Fig. 1,1 is fin, and 2 is cryosurface, and 3 is the evaporation cavity of inside heat pipe, and 4 is working medium, and 5 is the micro-channel heat-transfer area, and 6 is heating surface, and 7 are the heating thermal source.
Fig. 2 is the local enlarged diagram of micro-channel micro-channel heat-transfer area.
The specific embodiment
Below in conjunction with drawings and Examples technical scheme of the present invention is further described.Parameter in following examples does not constitute limitation of the invention.
The structure of gravity-type micro-channel flat plate heat pipe of the present invention as shown in Figure 1, whole heat pipe is a vertical cylinder or vertical square tube, some fin 1 evenly distributed being installed on the cryosurface 2 that cryosurface 2 is cooled off, cryosurface 2 belows are the evaporation cavity 3 of inside heat pipe, the working medium 4 of evaporation cavity 3 inside is carbon nano tube suspension, and liquid filled ratio is the 40-60% of evaporation cavity volume.The bottom surface of evaporation cavity 3 is a micro-channel heat-transfer area 5, evenly has micro-channel on the micro-channel heat-transfer area 5.
The back side of micro-channel heat-transfer area 5 is heating surfaces 6, heating thermal source 7 that is the element that need cool off.
Micro-channel of the present invention adopts rectangular cross sectional shape or triangular cross-sectional shape.Heat pipe sizes can design arbitrarily.
Fin 1 in the flat-plate heat pipe of the present invention on the cryosurface 2 uses the heat radiation of fan method for air-cooling, also can be designed to water-cooling.During use, the element of needs heat radiation (heating thermal source 7) is attached to the lower end (heating surface 6) of micro-channel flat plate heat pipe, by the working medium carbon nano tube suspension of micro-channel heat-transfer area 5 and evaporation cavity 3 inside, the heat of the element of needs heat radiations is delivered in upper end wind, the liquid.
The carbon nano tube suspension that the present invention adopts is the mixed liquor of deionized water and CNT, and the mass concentration scope of CNT is 0.5wt%-3wt% in the suspension.Described CNT generally can use CNT arbitrarily, and following multi-walled carbon nano-tubes (MWNT) is used in suggestion: the product of nanometer lane, Shenzhen Science and Technology Ltd., model L-MWNT-1020.Physical parameter is as follows: line footpath 10-20nm, length 5-15 μ m, purity 95-98%, surface area 40～300m
2/ g.
In one embodiment of the present of invention, in the heat-transfer area 5 the local structure for amplifying of micro-channel as shown in Figure 2, the micro-channel of the rectangular cross sectional shape of on the micro-channel heat-transfer area, evenly gathering, the rib width 0.5mm of each micro-channel, groove width 0.5mm, groove depth 0.8mm forms with the line cutting processing.
When gravity-type micro-channel flat plate heat pipe of the present invention moves, under the low heat loads operating mode, move several minutes earlier, the CNT that is deposited in heat pipe evaporation cavity 3 bottoms is suspended again, can normally move.
The liquid filled ratio of carbon nano tube suspension is got the 40-60% of evaporation cavity volume among the present invention, and in this scope, filling amount heat exchanging characteristic does not have influence substantially.
It is that the data of embodiment of working medium are as shown in table 1 that the present invention adopts the carbon nano tube suspension of different quality concentration:
Table 1
| The CNT mass concentration | The heat pipe liquid filled ratio | Operating pressure (Pa) | Heat hot current density (kW/m 2) | The CHF increase rate | The boiling heat transfer coefficient increase rate |
| 0.5wt％ | 40％ | 7.2kPa | 260 | 125％ | 56％ |
| 3wt％ | 40％ | 7.2kPa | 260 | 250％ | 92％ |
| 2wt％ | 40％ | 7.2kPa | 260 | 260％ | 120％ |
| 2wt％ | 40％ | 20.4kPa | 260 | 180％ | 50％ |
| 2wt％ | 40％ | 100kPa | 260 | 80％ | 30％ |
Table 1 data show, gravity-type micro-channel flat plate heat pipe of the present invention with existing be that the flat-plate heat pipe of working medium is compared with the pure water, can very significant raising heat transfer characteristic, reduce the heat pipe thermal resistance, increase heat radiation power.Under same pressure, 2wt% is a best in quality concentration, can obtain maximum strengthening effect.Under the same concentration conditions, pressure is low more, and the strengthening effect that heat pipe played is obvious more.In pressure limit is between 7.2kPa～100kPa, when the CNT mass concentration is 2wt%, with traditional be that the heat pipe of working medium is compared with water, the heat pipe thermal resistance can reduce by 50%, heat exchange power is maximum to improve about 1.7 times, its maximum heat radiation power consumption can reach 130W/cm
2
Claims (5)
1, a kind of is the gravity-type micro-channel flat plate heat pipe of working medium with the carbon nano tube suspension, some fin (1) are evenly distributed to be installed on the cryosurface (2), evaporation cavity (3) inside of cryosurface (2) below is marked with working medium (4), the bottom surface that it is characterized in that described evaporation cavity (3) is micro-channel heat-transfer area (5), and the micro-channel heat-transfer area evenly has micro-channel on (5); Described working medium (4) is carbon nano tube suspension, and liquid filled ratio is the 40-60% of evaporation cavity volume.
2, according to claim 1 be the gravity-type micro-channel flat plate heat pipe of working medium with the carbon nano tube suspension, it is characterized in that described carbon nano tube suspension is the mixed liquor of deionized water and CNT, the mass concentration of CNT is 0.5-3% in the suspension.
3, according to claim 1 be the gravity-type micro-channel flat plate heat pipe of working medium with the carbon nano tube suspension, it is characterized in that described micro-channel adopts rectangular cross sectional shape or triangular cross-sectional shape.
4, according to claim 2 be the gravity-type micro-channel flat plate heat pipe of working medium with the carbon nano tube suspension, it is characterized in that described CNT is the multi-walled carbon nano-tubes of line footpath 10-20nm, length 5-15 μ m.
5, according to claim 3 be the gravity-type micro-channel flat plate heat pipe of working medium with the carbon nano tube suspension, it is characterized in that described micro-channel adopts rectangular cross sectional shape, the rib width 0.5mm of each micro-channel, groove width 0.5mm, groove depth 0.8mm.
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| CN 200710043438 CN101082468A (en) | 2007-07-05 | 2007-07-05 | Gravity force type micro-chute flat-plate hot pipe with carbon nano-tube suspending liquid as working substance |
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| CN 200710043438 CN101082468A (en) | 2007-07-05 | 2007-07-05 | Gravity force type micro-chute flat-plate hot pipe with carbon nano-tube suspending liquid as working substance |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101858701A (en) * | 2009-04-03 | 2010-10-13 | 索尼公司 | Heat transfer unit (HTU), electronic equipment and heat transport device manufacturing method |
| CN103429061A (en) * | 2013-09-04 | 2013-12-04 | 中山佳一电子技术有限公司 | Empty-belly heat pipe radiator |
| CN107167008A (en) * | 2017-04-28 | 2017-09-15 | 华北电力大学 | A kind of ultra-thin panel heat pipe and its manufacture method |
| CN107816907A (en) * | 2016-09-13 | 2018-03-20 | 中国科学院工程热物理研究所 | A kind of micro-nano compound structure surface is heat sink and its method for enhanced heat exchange |
-
2007
- 2007-07-05 CN CN 200710043438 patent/CN101082468A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101858701A (en) * | 2009-04-03 | 2010-10-13 | 索尼公司 | Heat transfer unit (HTU), electronic equipment and heat transport device manufacturing method |
| CN103429061A (en) * | 2013-09-04 | 2013-12-04 | 中山佳一电子技术有限公司 | Empty-belly heat pipe radiator |
| CN107816907A (en) * | 2016-09-13 | 2018-03-20 | 中国科学院工程热物理研究所 | A kind of micro-nano compound structure surface is heat sink and its method for enhanced heat exchange |
| CN107167008A (en) * | 2017-04-28 | 2017-09-15 | 华北电力大学 | A kind of ultra-thin panel heat pipe and its manufacture method |
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