JPH0731024B2 - Thermosyphon type heat pipe - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pipe in which a condensable fluid such as water or chlorofluorocarbon is enclosed in a container such as a degassed pipe. The present invention relates to a thermosyphon-type heat pipe in which a condensed working fluid is returned by gravity.

[0002]

2. Description of the Related Art As is well known, a heat pipe encloses a fluid (water, alcohol, flon, etc.) that evaporates and condenses in a target temperature range as a working fluid in a deaerated closed container to prevent heat input. After the working fluid evaporates at a certain portion and the vapor flows into the heat radiating portion, the heat is deprived and condensed to mainly transport the heat as latent heat of vaporization of the working fluid. Therefore, the apparent thermal conductivity of the heat pipe may reach several tens of times that of metals such as copper.

As described above, in the heat pipe, the working fluid mainly transfers heat as its latent heat of vaporization. Therefore, in order to continue the heat transfer, the condensed working fluid in the liquid phase is heated to a portion having heat input, that is, It is necessary to recirculate to the evaporation part, and in the most general heat pipe, the pumping action for the recirculation is performed by the capillary action by the wick. Known wicks of this type include fine grooves, wire netting, and porous sintered bodies. Even heat pipes equipped with these wicks show excellent heat transport characteristics depending on the application. There is a problem that the maximum heat transfer amount is suppressed and the thermal resistance is large due to the capillarity limit and the boiling limit at.

Conventionally, there is also a type of heat pipe in which the liquid-phase working fluid is returned to the evaporation portion by gravity, which is known as a thermosyphon type heat pipe. This is the evaporation part at the bottom of the container containing the working fluid.
It uses the upper part as a condensing part for heat transfer, and the working fluid liquefied in the condensing part flows down to the evaporating part by gravity, so that no wick is required, and the working part actively boils the working fluid. You can Therefore, in such a thermosyphon type heat pipe, as compared with the conventional general heat pipe utilizing the pump action by the wick,
A heat flux of 0 to 100 times can be achieved.

[0005]

In the above-mentioned thermosyphon type heat pipe, the working fluid liquefied in the condensing section flows down along the wall surface of the container. In that case, however, the working fluid tends to flow in some lines. It hardly spreads like a film on the entire wall surface of the container. Therefore, the area where the working fluid evaporates in the portion above the portion where the working fluid is stored in the evaporation portion is narrowed, and the heat transport capacity is limited in this respect.

Further, when the heat input to the evaporation section is stopped, the working liquid remains in the bottom of the evaporation section. Therefore, when the entire evaporation section is heated to start heat transfer, the working fluid becomes The heat transfer is limited to the portion where the working fluid is accumulated (that is, the liquid column portion), and since there is no working fluid above it, evaporation of the working fluid does not occur here. That is, since the heat transfer area of the working fluid and the evaporation of the working fluid at the time of starting are small, there is a problem in so-called rising characteristics.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a thermosyphon-type heat pipe which is excellent in both heat transport capacity and rising characteristics.

[0008]

In order to achieve the above-mentioned object, the present invention arranges a container in which a working fluid for evaporating and transporting heat is enclosed in a vertical direction, and at the bottom of the container. the is heated from the outside and the evaporation portion for evaporating the working fluid, and the thermosyphon type heat pipe and the condensing unit which condenses the working fluid by radiating a top, along the inner surface of the evaporation section of the pre-SL container ,
Place the striatum of the fine pore structure that is formed by the combined processing or braiding process twisted fine lines on the outer periphery of the core wire spirally
The working fluid permeates the striatum and
That you configured to flow down in the circumferential direction of the container in which the features.

Further, according to the present invention, the fine pore structure material may be replaced by a fine wire twisted or braided to form a porous body formed by foam molding.

[0010]

In the thermosyphon type heat pipe of the present invention, the working fluid evaporates in the lower portion of the container, and the vapor dissipates and condenses in the upper portion of the container to transport heat as latent heat of vaporization of the working fluid. Further, the condensed working fluid flows down to the evaporation section due to gravity. In that case, the heat pipe of the present invention, flows down from spiral striatum on the inner surface of the container are placed along, hydraulic fluid while being guided in the circumferential direction of the inner surface of the container by the striatum, thus operating The liquid spreads over the entire inner surface of the container, that is, the inner surface of the evaporation section. In that case, some of the hydraulic fluid may flow over the linear body and flow down, and the hydraulic fluid flowing in this way tends to spread in the form of a liquid film due to the linear arrangement of the linear body. As a result, the area in which the working fluid comes into contact with the inner surface of the evaporating portion is increased, so that the evaporation amount of the working fluid and thus the heat transport amount as the heat pipe increases. Further, since the filamentous body is formed by twisting or braiding thin wires, or is provided with a fine pore structure material of a porous body formed by foam molding on at least the outer surface, the hydraulic fluid permeates into the inside thereof. The working liquid is spread and spread to the inner surface of the evaporating portion, and the working liquid is held above the liquid column portion of the evaporating portion.
By increasing the contact area of the working fluid with the inner surface of the evaporator, the amount of the working fluid that evaporates when heat is applied to the evaporator from the stopped state to start it, and as a result, the rising characteristics are improved.

[0011]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a schematic view showing an embodiment of the present invention, in which a closed container (container) 1 has an axis extending vertically. The working fluid, such as water and chlorofluorocarbon, which evaporates and condenses in the target temperature range in a degassed state, is enclosed in the interior of the container. The lower portion of the container 1 shown by reference numeral 3 in FIG. 1 is an evaporation portion that is heated from the outside, and the upper portion of the container 1 is a condensation portion that radiates heat to the outside.

Inside the evaporating section 3, a linear member 5 is arranged along the inner wall surface in a spiral shape. This striatum 5
Is for guiding the flow of the working fluid (working fluid) 2 in the liquid phase and holding a part of the working fluid 2, and is configured as shown in FIG. That is, FIG. 2 is a partial perspective view showing an example of the filamentous body 5, and the filamentous body 5 shown here is formed by braiding a fine metal wire on the outer periphery of the core wire 6 having necessary strength and elasticity such as a metal wire. It has a structure in which a fine hole structure material 7 made of a braided or twisted material is provided, and the gaps between the fine metal wires become fine holes, and the working fluid 2 is permeated and held in the gaps and the opening is adjusted according to the opening diameter. It is designed to generate capillary pressure. Therefore, as the fine wires forming the fine pore structure material 7, those having excellent wettability of the hydraulic fluid 2 are adopted.

In the thermosyphon type heat pipe shown in FIG. 1, the working fluid 2 evaporates due to heat input in the evaporating section 3.
The vapor flows to the side of the condenser 4 having a low pressure, and the condenser 4
It contacts the inner wall surface of the and heat is taken away to condense. That is, the working fluid 2 mainly transfers the heat from the evaporator 3 to the condenser 4 as its latent heat of vaporization. The condensed hydraulic fluid 2 is stored in the container 1
Although it flows down to the evaporation part 3 side by gravity along the inner surface of the above, when it reaches the portion of the linear body 5, most of it flows down along the linear body 5. That is, in the evaporation section 3, the hydraulic fluid 2
Since the gas flows spirally along the filamentous body 5, it is dispersed in both the vertical direction and the circumferential direction of the evaporation unit 3. At the same time, since the outer peripheral portion of the linear member 5 is formed by the fine pore structure material 7, a part of the hydraulic fluid 2 permeates and is retained in the fine pore structure material 7.
The fine pore structure material 7 also disperses the hydraulic fluid 2 in the entire evaporation section 3 . Further, a part of the hydraulic fluid 2 flowing down from the condensing part 4 is, as schematically shown in FIG.
However, even in this case, the direction in which the linear body 5 flows down is changed to the circumferential direction, so that the hydraulic fluid 2 is also dispersed in the entire evaporation section 3 by such an action.

The working fluid 2 dispersed in the entire evaporation section 3 as described above is heated again at each location to be evaporated and heat is transported. Therefore, the area where the working fluid 2 evaporates, that is, the effective area of the evaporating portion 3 is widened, so that the evaporation amount of the working fluid 2 increases and the heat transport capability is excellent.

When the heat input to the evaporation unit 3 is stopped, the working fluid vapor radiates heat in the condensation unit 4 and is condensed momentarily, and the resulting working liquid 2 flows down along the wall surface of the container 1. Therefore, most of the enclosed working fluid 2 accumulates at the bottom of the evaporation section 3, but as described above, the working fluid 2 flowing down along the wall surface of the container 1 has fine holes in the linear body 5 in the middle thereof. Since it penetrates into the structural material 7, a part of the working fluid 2 is retained by the filament 5 at a portion above the liquid pool portion in a state where heat input is stopped. Therefore, when heat input to the evaporation unit 3 is started to restart heat transport, both the working liquid 2 accumulated at the bottom of the evaporation unit 3 and the working liquid 2 held by the filament 5 start to evaporate. Therefore, the amount of the working fluid vapor, that is, the amount of heat transport is close to the amount of heat transport during steady operation, and therefore the amount of heat transport during startup is large, and the so-called rising characteristic is excellent.

In the above embodiment, an example in which a braided or twisted thin wire of metal or the like is used as the fine pore structure material 7, the fine pore structure material 7 in the present invention is essentially a working fluid. The porous body 10 formed by foam molding as shown in FIG. 4 may be used, or the porous body 10 as shown in FIG. 5 may be used. A porous structure material 11 may be provided on the outer periphery of 10 by using a thin wire such as a braid as a material. Or need not whole striatum 5 in the invention of octopus <br/> are continuous in one, multiple several striatal arranged spirally may be provided at regular intervals . Further, the "filamentary body" in the present invention also includes a so-called band-shaped body having a rectangular flat cross section.

[0017]

As is apparent from the above description, according to the present invention, since the filamentous body having the fine pore structure material on the outer periphery is spirally arranged on the inner surface of the evaporation portion, the working fluid is supplied to the evaporation portion. Since the liquid can be widely dispersed on the inner surface and the working liquid can be held above the liquid pool portion even when the heat transport is stopped, the amount of the working fluid evaporated at the time of starting can be increased. According to the above, it is possible to obtain a thermosyphon type heat pipe having excellent heat transport ability and rising characteristics.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

FIG. 2 is a partial perspective view showing an example of the linear body.

FIG. 3 is a schematic diagram showing a situation in which a hydraulic fluid flows down over a linear body.

FIG. 4 is a partial perspective view showing another example of the linear member.

FIG. 5 is a partial perspective view showing still another example of the linear body.

[Explanation of symbols]

1 ... Container, 2 ... Working fluid, 3 ... Evaporating part, 4
… Condensation part, 5 ... Striatum, 7 ... Micropore structure material, 10
... Porous body, 11 ... Porous structure material.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Shotaro Yoshida 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Wire Co., Ltd. (72) Inventor Masataka Mochizuki 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Wire Co., Ltd. (72) Inventor Yuuji Saito 1-5-1, Kiba, Koto-ku, Tokyo Shikura Kumagai, Examiner, Fujikura Electric Wire Co., Ltd. (56) Reference JP-A-55-110888 (JP, A) Kai 57-33790 (JP, A)

Claims (2)

[Claims] 1. A container, in which a working fluid that evaporates and transports heat is enclosed, is arranged vertically, and a lower portion of the container serves as an evaporating portion for evaporating the working fluid by being heated from the outside, and an upper portion. In the thermosyphon type heat pipe which was used as a condensing part for radiating heat and condensing the working fluid,
Along the inner surface of the evaporation section of the pre-SL container, the core wire of the
The striatum combined processing or braiding machined microporous structure that is formed by twisting a thin line on the outer circumference arranged spirally, wherein
The working fluid permeates the filament and the circumference of the container.
Thermosiphon heat pipe characterized that you configured to flow down direction. 2. A container in which a working fluid that evaporates and transports heat is enclosed is arranged vertically, and a lower portion of the container serves as an evaporating portion for evaporating the working fluid by being heated from the outside, and an upper portion. In the thermosyphon type heat pipe which was used as a condensing part for radiating heat and condensing the working fluid,
Along the inner surface of the evaporation section of the pre-SL container, the core wire of the
Striatum microporous structure that is formed by the foamed molding to the outer periphery
The body is spirally arranged so that the working fluid is immersed in the filament body.
It is transparent and is designed to flow down in the circumferential direction of the container.
Thermosiphon heat pipe, wherein the kite.