JP2010054121A - Variable conductance heat pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the stable starting and stable operation of a variable conductance heat pipe irrespective of a situation in preservation, transportation, and installation. <P>SOLUTION: In the variable conductance heat pipe, a working fluid and a non-condensible gas are sealed in an airtight container 1 extended in an axial direction, a heating source 9 is attached to one side of the airtight container 1, and a cold source 10 is attached to the other side. The pipe is composed so that a portion 15 with more favorable water conductivity than other portions is provided at one part of a cross section perpendicular to an axis of the airtight container 1, and the portion with favorable water conductivity is extended in the axial direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cooling device for controlling the temperature of an electronic device or the like, and more particularly to a cooling device using a variable conductance heat pipe.

  In the conventional cooler for electronic equipment, in order to stably obtain a desired function, it has been important to cool the temperature of the electronic equipment to an allowable temperature or less. The cooler includes a radiation type, a natural air cooling type, a forced air cooling type, a liquid cooling type, and a boiling cooling type. In recent years, a heat pipe in which an appropriate amount of working fluid is sealed in a sealed container is also frequently used. It is like that. These coolers have device-specific thermal resistance, and in actual use, the temperature of the electronic device increases as the heat generation amount of the electronic device increases and the ambient environment temperature increases. As the flow rate of the cooling medium (air, water, etc.) flowing therethrough increases, the electronic device temperature decreases. Therefore, the temperature of electronic equipment varies due to variations in operating factors or environmental factors, and a heat cycle is always generated in practice. This heat cycle generates an internal stress due to a difference in coefficient of linear expansion of each material constituting the electronic device, and is a major cause of destruction of the electronic device, that is, shortening the life of the electronic device.

  Against this background, a cooling device that suppresses the above heat cycle is required for extending the life of electronic devices. As one of such cooling devices, non-condensable gases (helium, argon, etc.) are formed inside the heat pipe. , Nitrogen, etc.) have been proposed (for example, Patent Document 1).

Japanese Patent Laid-Open No. 10-122775 (2 pages, FIG. 1)

  In such a variable conductance heat pipe, a working fluid (liquid and vapor) and non-condensable gas are sealed inside a sealed container consisting of a heat receiving part, a heat insulating part (transport part), a heat radiating part, and a gas reservoir. However, during manufacturing, storage, transportation, and installation, the working liquid flows into the gas reservoir because of various postures, and the working fluid flows into the gas reservoir due to a sudden temperature change. There was not always liquid in the heat receiving part, and there was a problem in the stable start-up and stable operation of the variable conductance heat pipe. Therefore, mass production of the variable conductance heat pipe has been difficult.

  In the variable conductance heat pipe according to the present invention, the working fluid and the non-condensable gas are sealed in a sealed container extending in the axial direction, and one of the sealed containers is attached to a heat source and the other is attached to a cold heat source. A part with better water conductivity than the other part is provided in a part of the cross section perpendicular to the axis of the closed container, and the good water conductivity part extends in the axial direction.

  According to the present invention, it is possible to provide stable start-up and stable operation of the variable conductance heat pipe regardless of the situation during storage, transportation, and installation.

Embodiment 1 FIG.
FIG. 1 is a sectional view showing a variable conductance heat pipe according to Embodiment 1 of the present invention. In the figure, the left is a cross-sectional view including the axis of the sealed container constituting the variable conductance heat pipe, and the right is a cross-sectional view perpendicular to the axis, that is, an enlarged view of the AA cross section. A heat receiving part 2 (evaporating part), a heat insulating part 3 (transporting part), a heat radiating part 4 (condensing part), and a non-condensable gas reservoir part 5 are formed from the end of the sealed container 1. The working fluid (liquid 6 and its vapor 7) and non-condensable gas 8 are sealed. As shown in the enlarged A-A cross-sectional view, a part of the inner wall of the sealed container 1 is provided with unevenness, and the unevenness extends in the axial direction of the closed container 1. The heat receiving unit 2 is in contact with the heat source 9 and the heat radiating unit 4 is in contact with the cold source 10, whereby heat is transferred from the higher temperature heat source 9 to the heat receiving unit 2 and further transmitted to the liquid 6 in the heat receiving unit 2. 6 absorbs heat in the form of latent heat and evaporates or boils, generating steam 7, steam 7 or steam 7 and liquid 6 flow into heat radiating section 4 through heat insulating section 3, while steam 7 condenses, The stored latent heat is released to the heat radiating unit 4, and the released heat is radiated from the heat radiating unit to the cooler heat source 10 having a lower temperature. At that time, the condensate (liquid 6) generated by condensing the vapor 7 is recirculated from the heat radiating unit 4 to the heat receiving unit 2 through the heat insulating unit 3 by gravity or capillary force. Due to the circulation of the vapor 7 and the liquid 6, the heat generated in the heat source 9 is continuously transmitted (exhausted heat) to the cold heat source 10. On the other hand, the non-condensable gas 8 sealed in the sealed container 1 passes through the heat insulating part 3 and the heat radiating part 4 along with the movement of the vapor 7 or the vapor 7 and the liquid 6, and then the non-condensable gas reservoir 5 or the non-condensable gas. It is moved to the heat radiating part 4 on the side of the reservoir 5 and accumulated and stagnated. When the non-condensable gas 8 stagnates, the vapor 7 becomes difficult to enter the non-condensable gas 8 and forms an interface 11 between the vapor 7 and the non-condensable gas 8. The steam 11 continuously moves the non-condensable gas 8 while the interface 11 moves. When the pressure of the steam 7 and the non-condensable gas 8 reaches equilibrium, the movement of the interface 11 stops and the position is stabilized. . Therefore, when the interface 11 is located in the non-condensable gas reservoir 5, the heat 7 is condensed over the entire heat dissipating part 4, so that 100% heat dissipating ability is obtained. Since the heat dissipation area is reduced, the heat dissipation capability is reduced (0 <heat dissipation capability <100% variable), and when located in the heat insulating portion 3 or the heat receiving portion 2, heat insulation (heat dissipation capability 0%) can be achieved. However, since heat is partially transferred due to heat conduction that travels through the wall of the hermetic container 1, there is actually a slight ability to dissipate heat. The description of the operation so far is the operation principle of the variable conductance heat pipe.

  In the variable conductance heat pipe, three kinds of fluids of liquid, vapor and non-condensable gas are sealed in a sealed container 1 in terms of structure. In principle, it is preferable that the non-condensable gas stays in the non-condensable gas reservoir 5, but in reality, vapor and non-condensable gas are mixed due to molecular diffusion. Neon used as non-condensable gas has a molecular weight of 20, nitrogen of 28, and argon of 40. For example, when water is used as a working fluid, the molecular weight of water is 18 and is lighter, and usually a heat receiving unit installed below. 2, the non-condensable gas 8 is more likely to stagnate due to the influence of gravity, and conversely, the vapor 11 is more likely to stagnate in the non-condensable gas reservoir 5 that is normally installed above. Furthermore, since the vapor may condense in the non-condensable gas reservoir 5 and the liquid may flow into the non-condensable gas reservoir 5 via the heat radiating unit 4, the above three types of fluids actually exist. There is. These do not cause any particular problems with respect to storage, transportation, installation, etc. of the variable conductance heat pipe. However, due to the presence of liquid in the non-condensable gas reservoir 5 in the actual start-up and operation as a heat dissipation element. The liquid in the heat receiving part 2 is insufficient, causing dryout in the heat receiving part 2 and causing the problem that the temperature of the heat receiving part 2 is thermally runaway. Accordingly, the liquid present in the non-condensable gas reservoir 5 must be configured to always return to the heat receiving unit 2 during actual use.

  However, in the variable conductance heat pipe having the conventional structure shown in FIG. 2 (the difference in structure from the present invention will be described later), when the sealed container 1 is thin, if liquid is present at the end of the sealed container 1, the vapor and the heat cannot be generated. The liquid is difficult to flow down due to the capillary force acting on the gas-liquid interface 14 which is the boundary between the gas compartment 12 made of condensed gas and the liquid compartment 13 where the liquid stagnates. In addition, when the end of the sealed container 1 is filled with liquid as shown in FIG. 2, the liquid at the end of the sealed container 1 changes into vapor and expands in a normal heat pipe without non-condensable gas. However, in the case of a variable conductance heat pipe, non-condensable gas exists in the gas compartment 12, so that the internal pressure is not so small that the liquid at the end of the sealed container 1 changes to vapor, and the liquid is in the direction of the heat receiving part 2. Gas (compressible fluid, that is, vapor) is not generated at the end of the closed container 1 (the liquid is attracted to the end of the closed container 1 by a vacuum) and is difficult to move. Furthermore, when the liquid is about to move, in the case of a heat pipe having no normal non-condensable gas, the vapor in the gas compartment 12 is condensed and the pressure in the gas compartment 12 does not rise, but the variable conductance heat pipe In this case, since the non-condensable gas exists, the pressure in the gas compartment 12 increases with the movement of the liquid, so that the movement of the liquid is hindered. Therefore, the liquid tends to stagnate in the non-condensable gas reservoir 5, and as a result, the liquid in the heat receiving unit 2 is insufficient, and the variable conductance heat pipe may not be normally started and operated.

  Hereinafter, the structure and operation of the present invention will be described in detail with reference to FIG. As shown in the AA cross-sectional enlarged view of FIG. 3 (the same applies to the AA cross-sectional enlarged view of FIG. 1), the present invention has better water conductivity than the other portion 16 in the same cross section of the sealed container 1. A portion 15 is provided. Specifically, the portion 15 having good water conductivity has irregularities in a part of the inner wall cross-section circumferential direction of the sealed container 1, and the concave and convex portions extend in the axial direction of the sealed container (the direction in which the liquid or vapor moves). By providing, a portion having good water conductivity is formed. Due to the non-uniformity of the water conductivity over the circumferential direction, the dome-shaped gas-liquid interface 11 as shown in FIG. 1 is not formed for some reason, and the liquid 6 in the vicinity of the non-condensable gas reservoir 5 as shown in FIG. When the liquid compartment 13 is present, a non-uniform shape (a shape that is not an axis target) in which the portion 15 having good water conductivity is partially dripped is formed. This liquid dripping part preferentially moves the liquid 6 and causes the pressure in the gas compartment 12 not to rise, so that the gas compartment 12 and the liquid compartment 13 are interchanged, and the liquid 6 moves to the heat receiving portion 2, and the variable conductance heat. The pipe works normally.

  On the other hand, the heat receiving part 2 has the same effect, and has a variable conductance having a conventional structure as shown in FIG. 2, i.e., having no uniform treatment or processing on the inner wall of the sealed container 1 and having uniform water conductivity in the circumferential direction. In the heat pipe, the heat receiving portion 2 is not necessarily filled with liquid because of the structure, and may be filled with non-condensable gas as the worst condition. When filled with non-condensable gas, even if the liquid tries to flow in from the heat radiating section 4, a gas-liquid interface 17 between the non-condensable gas and liquid is formed as shown in FIG. 2, and uniform capillary pressure is generated in the cross section. Cover with liquid. When the heat receiving part 2 is heated, the non-condensable gas in the heat receiving part 2 expands, and the gas-liquid interface 17 moves toward the heat insulating part 3. If there is no liquid in the heat receiving part 2 at this time, the above normal heat transport is not performed and the temperature of the heat receiving part 2 rises. As a result, since the liquid does not flow into the heat receiving portion 2, the normal variable conductance heat pipe cannot be operated. On the other hand, in the variable conductance heat pipe having the structure of FIG. 3 (same as in FIG. 1) according to the present invention, unlike the conventional structure shown in FIG. Since there is a good portion 15, a dome-like gas-liquid interface 17 as shown in FIG. 2 is formed due to the non-uniformity of the water conductivity over the circumferential direction as in the case where liquid is present in the non-condensable gas reservoir 5. Therefore, the non-uniform shape (shape which is not an axis | shaft object) which the part 15 with good water-conductivity dripped partially forms. The liquid dripping portion preferentially moves the liquid, and the liquid moves to the tip of the heat receiving portion 2. The liquid flowing into the tip of the heat receiving unit 2 is evaporated or boiled by the application of heat from the heat generating source 9 to generate steam, and the uncondensed gas stagnated in the heat receiving unit 2 is sent to the heat insulating unit 3. Then, the non-condensable gas dispersed in the hermetic container 1, in particular, the non-condensable gas existing in the heat receiving part 2 is moved and accumulated in the non-condensable gas reservoir part 5 by the operation of the variable conductance heat pipe itself. The liquid can be continuously supplied to 2 and the steam can be continuously sent out from the heat receiving unit 2, and the operation as a variable conductance heat pipe can be stabilized.

  The portion 15 having good water conductivity deforms a part of the inner wall in the cross section in addition to those shown in FIGS. 1 and 3, and has a non-smooth shape (a shape having a bending point in the cross section, 180 ° or more or 180 ° or less). It is also possible to realize a shape having a point), for example, a teardrop shape shown in FIG. 4A, a ridge shape shown in FIG. 4B, and a shape having a plurality of wedge-shaped channels shown in FIG. Further, a part in the circumferential direction of the inner wall in the cross section of the sealed container 1 having different hydrophilicity, for example, a part of which the surface roughness is partly roughened, partly UV treatment (surface activation), oxidation treatment, or It can also be realized by subjecting a part of the inner wall to a treatment for improving water conductivity, such as an ozone-treated one or a part having a water-repellent film adhered to it.

  The heat source 9 of the present invention is not limited as long as it applies heat to the heat receiving part 2 and there is no particular limitation on the size and shape, and heat dissipation of the heat generating part, heater, heat transport device, heat pump and heat exchanger of the electronic equipment. A fluid such as a solid, a high-temperature liquid, and a high-temperature gas may be used. Note that heat may be applied by radiation such as the sun or a high-temperature object.

  On the other hand, the cold heat source 10 is not particularly limited as long as it receives heat from the heat radiating unit 4, and is not particularly limited in size and shape, such as a fluid such as water and air, a heat receiving device of a heat transport device, a heat pump or a heat exchanger, and Solids such as soil and structures may be used. A distant material using radiation may also be used.

  The hermetic container 1 is an airtight container that stores liquid, vapor, and non-condensable gas, and is preferably a metal that has almost no chemical reaction between the liquid and vapor and the inner wall of the hermetic container 1. For example, when the liquid is water, the material of the sealed container 1 is preferably copper, and when ammonia is used, a material that does not generate non-condensable gas due to a chemical reaction, such as aluminum or stainless steel, is preferable.

  The heat receiving unit 2 has a role of receiving heat from the heat source 9 and transmitting the heat to the liquid. Note that a structure that promotes boiling (a structure that traps a porous material or vapor provided on the surface) may be provided on the inner surface thereof.

  The heat insulating portion 3 is a passage through which liquid, vapor, and noncondensable gas move. The heat insulating part 3 may be exposed to a fluid such as air, may contact the structure to radiate heat, or may be insulated by providing a heat insulating material. Further, the heat radiating unit 4 has a role of condensing and liquefying the vapor and releasing the latent heat released at that time to the cold heat source 10. As shown in FIGS. 1 and 3, fins that increase the heat transfer area may be provided on the outer peripheral surface of the heat dissipating part 4 in order to promote heat dissipation to the cold heat source 10. In addition, as above-mentioned, the gas-liquid interface 15 may be located in the heat insulation part 3 and the thermal radiation part 4, and the one part plays the role of the channel | path or container which accommodates noncondensable gas.

  The non-condensable gas reservoir 5 has a role of storing non-condensable gas. When not in operation, it may contain liquids and vapors and non-condensable gases. The variable conductance heat pipe is provided at the end farthest from the heat receiving portion 2 with respect to the flow path of the variable conductance heat pipe, preferably provided at the uppermost portion of the component, and has a structure in which the inflowed liquid flows down to the heat radiating portion 4. .

  The liquid is a liquid that boils and evaporates and condenses, and may be a single component fluid such as water or ammonia, or a multicomponent fluid such as an antifreeze. Vapor is a gas in which a liquid or a part of the liquid is vaporized. The non-condensable gas is a gas that does not condense in the use environment, and is a helium, argon, neon, nitrogen, or the like under a normal environment. Preferably, it is a gas that does not chemically react with the material, liquid, or vapor of the hermetic container 1, and is more preferably an inert gas. In addition, non-condensable gas generated by a chemical reaction between the sealed container 1 and the liquid may be used in the initial stage of encapsulation.

Embodiment 2. FIG.
FIG. 5 is a sectional view schematically showing a variable conductance heat pipe according to Embodiment 2 of the present invention. The insert 19 is inserted into the variable conductance heat pipe having the conventional structure shown in FIG. With this insert 19, the inside of the sealed container 1 is divided into a flow path 20 having a large cross-sectional area and a flow path 21 having a small cross-sectional area, and a gas-liquid interface is formed in each flow path. In addition, the large cross-sectional flow path 20 and the small cross-sectional flow path 21 have an opening 18, and this opening 18 is continuous in the axial direction (a portion not continuous to the part, that is, the insert 19). Therefore, the opening 18 functions as a non-condensable gas discharge passage and a circumferential liquid suction port. A smaller capillary force is generated at the gas-liquid interface of the channel 20 having a large cross-sectional area, and a larger capillary force is generated at the gas-liquid interface of the channel 21 having a small cross-sectional area. A force non-equilibrium condition occurs. Therefore, the liquid stagnated at the end of the sealed container 1 moves to the flow path 21 where the capillary force is large (the gas-liquid interface 14 in the flow path 21 moves toward the heat receiving part 2), and the flow with a small capillary force is present. The gas-liquid interface of the path 20 moves toward the end of the sealed container 1. That is, the flow passage 21 portion having a small cross-sectional area is a portion having better water conductivity than the flow passage 20 portion having a large cross-sectional area, and serves as a liquid passage. As a result, during the variable conductance heat pipe operation, the same operation state as described in the first embodiment is obtained, and an appropriate amount of liquid is present in the heat receiving unit 2, and stable start-up and operation can be established.

  On the other hand, there is a similar effect in the heat receiving portion 2, and unlike the variable conductance heat pipe having the conventional structure in FIG. 2, an insert 19 is mounted in the heat receiving portion 2, and the flow path 20 having a large cross-sectional area and a small cross-sectional area are provided. Since the flow path 21 is divided, a non-equilibrium state of capillary force is generated in the flow path having the same cross section. Therefore, the flow path 21 having a large capillary force is filled with the liquid 6 (the tip of the heat receiving portion 2 is in contact with the liquid 6), while the non-condensable gas stagnates in the flow path 20 having a small capillary force. When the variable conductance heat pipe is operated, when heat is applied to the heat receiving unit 2, the liquid is in contact with the tip of the heat receiving unit 2, and steam is generated from the end of the heat receiving unit 2. Then, when moving to the heat radiating unit 4, the stagnated non-condensable gas is moved toward the non-condensable gas reservoir 5. In this way, the non-condensable gas dispersed in the hermetic container 1, particularly the non-condensable gas present in the heat receiving part 2, is moved and accumulated in the non-condensable gas reservoir part 5 by the operation of the variable conductance heat pipe itself. The liquid can be continuously supplied to the heat receiving unit 2 and the steam can be continuously sent out from the heat receiving unit 2 so that the operation as the variable conductance heat pipe can be stabilized.

  The insert 19 forms a non-equilibrium state of capillary force in the same cross section of the sealed container 1, and a dedicated passage for the liquid 6 is provided along the inner wall of the sealed container 1. What is necessary is just to insert in the airtight container 1 so that it may have the opening 18 which served as the discharge channel and the circumferential direction liquid suction port, and what inserted the board eccentrically may be used. In addition, when a dedicated passage that does not have the opening 18 is provided so that the cross section is completely partitioned in the cross section of the hermetic container 1, non-condensable gas is mixed and stagnated in the dedicated passage, and the liquid and its non-restriction in the dedicated passage. Due to the capillary force acting at the interface with the condensed gas, the liquid 6 cannot flow through the dedicated passage and cannot operate.

  In FIG. 5, the insert 19 has a concave plate shape, but may be a flat plate shape or a punching metal or a wire mesh. Further, the cross-sectional shape may be a V shape shown in FIG. 6 or even a W shape, and in these V shape or W shape, the inserted insert 19 is fixed. It has the effect of getting stuck. As described above, the cross-sectional shape of the insert 19 may be any shape as long as the inside of the sealed container 1 is divided into a large cross-sectional flow path 20 having an opening 18 and a small cross-sectional flow path 21. May be good.

  Further, in FIG. 5, the sealed container 1 is shown as a straight pipe, but as shown in FIG. 7, the end may be bent, that is, a bent portion may be provided around the heat insulating portion 3. By having this, there is an effect that the insert 19 inserted into the sealed container 1 is fixed and cannot move. Further, as the insert 19, as shown in FIG. 8, if a plate-like thing having a portion with a widened width is used as the insert 19, and the portion with the widened width is installed around the bent portion, the insert 19 is There is a more fixed effect. It goes without saying that the insert 19 having an expanded middle portion is not only effective in the closed container 1 having a bent portion as shown in FIG. 7, but also effective in a straight pipe as shown in FIG. Furthermore, by bending or curving the expanded portion of the insert 19 having a portion expanded in the middle, there is an effect that the insert 19 can be reliably decentered and fixed particularly when inserted into a straight pipe. In addition, as shown in FIG. 9, various structures that are normally employed as the structure for fixing the insert 19 eccentrically, such as bending the end of the insert 19 and inserting a separate spacer, etc. Is possible.

Embodiment 3 FIG.
FIG. 10 is an enlarged sectional view showing a section perpendicular to the axis of the variable conductance heat pipe according to the third embodiment of the present invention. A rod 19 having a dense cross section as shown in FIG. 10 may be inserted eccentrically. In this case, the space narrowed between the rod and the sealed container 1 is a portion having good water conductivity. A stranded wire may be used in place of the bar in FIG. 7, and in the stranded wire, a narrow space between the strands is also a portion having good water conductivity. Further, instead of a straight bar, a thin line spiraled may be used to be inserted along the inner wall of the sealed container 1, and in this case, a portion having good water conductivity is formed in a spiral. .

  As the material of the insert 19 shown in the second and third embodiments, oxygen-free copper is suitable, and after washing with acetone or the like in order to remove surface deposits, a material oxidized at a high temperature is used. The channel 21 having a small cross-sectional area can be made more water-conductive.

  In the second and third embodiments, grooves may be provided in the axial direction on the inner wall of the sealed container 1 so that the inner wall has an uneven surface. The grooves may be provided uniformly in the circumferential direction, may be provided unevenly, or may be provided spirally.

  As described above, the portion having good water conductivity in the present invention is the same as that of the first embodiment in that a part of the inner wall of the sealed container is provided with unevenness or is deformed so that the other inner wall surface part is part of the inner wall surface. This can be realized by forming a portion where the liquid spreads more in the axial direction. It can also be realized by applying a treatment for improving hydrophilicity to a part of the inner wall surface. Further, as described in the second and third embodiments, it can be realized by inserting an insert and forming a narrow space with the inner wall. In addition, as for the good and bad water conductivity, when the liquid is dropped on the part where the good and poor water conductivity is to be confirmed, the part where the liquid spreads longer in the axial direction than the other part is the part with good water conductivity. I can judge.

  The present invention described in the first to third embodiments is particularly effective for a thin sealed container in which the working fluid is difficult to move due to the surface tension of the working fluid. For example, when the working fluid is water, it is effective when the diameter of the sealed container is about 10 mm or less, and is particularly effective for a small-sized sealed container having a diameter of about 6 mm or less. Therefore, it is suitable for applications in which the amount of heat that can be transported by one variable conductance heat pipe is small, and is suitable for cooling, for example, a semiconductor laser having an output of several W. In semiconductor lasers, the temperature change during operation greatly affects the oscillation wavelength and output of the laser.Therefore, the characteristics of the variable conductance heat pipe, in which the temperature change of the heat receiving part is small during the operation of the heat source, can be effectively utilized. Therefore, it can be said that the present invention is suitable for the present invention.

It is a schematic sectional drawing which shows the principal part of the variable conductance heat pipe by Embodiment 1 of this invention. It is a schematic sectional drawing which shows the principal part of the conventional variable conductance heat pipe. It is a schematic sectional drawing for demonstrating operation | movement of the variable conductance heat pipe by Embodiment 1 of this invention. It is sectional drawing which shows the modification of the variable conductance heat pipe by Embodiment 1 of this invention. It is a schematic sectional drawing which shows the principal part of the variable conductance heat pipe by Embodiment 2 of this invention. It is a schematic sectional drawing which shows the modification of the insert by Embodiment 2 of this invention. It is a schematic sectional drawing which shows the principal part of the modification of the variable conductance heat pipe by Embodiment 2 of this invention. It is a figure which shows an example of the insert by Embodiment 2 of this invention. It is a schematic sectional drawing which shows the principal part of the other modification of the variable conductance heat pipe by Embodiment 2 of this invention. It is a schematic sectional drawing which shows the insert by Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Airtight container, 2 Heat receiving part, 3 Heat insulation part, 4 Heat radiation part, 5 Non-condensable gas reservoir part, 6 Liquid, 7 Steam, 8 Non-condensable gas, 9 Heat source, 10 Cold source, 11 Interface, 12 Gas section, 13 Liquid compartment, 14 gas-liquid interface, 15 well-conducting part, 16 poorly-conducting part, 17 gas-liquid interface, 18 opening, 19 insert, 20 large cross-sectional flow path, 21 small cross-sectional flow path.

Claims (12)

A variable conductance heat pipe in which a working fluid and a non-condensable gas are sealed in a sealed container extending in the axial direction, and one of the sealed containers is attached to a heat source and the other is attached to a cold heat source. A variable conductance heat pipe characterized in that a portion having a better water conductivity than the other portion is provided in a part of the cross section, and the good water conductivity portion extends in the axial direction. 2. The variable conductance heat pipe according to claim 1, wherein an insert is eccentrically inserted into the sealed container, and a portion having good water conductivity is formed in a space between the inner wall of the sealed container and the insert. . A flow path with a large cross-sectional area and a flow path with a small cross-sectional area are formed between the large cross-sectional area and a flow with a small cross-sectional area so as to form a flow path with a large cross-sectional area and a flow path with a small cross-sectional area between the inner wall of the closed container. 3. The variable conductance heat pipe according to claim 2, wherein an insert is inserted eccentrically so as to communicate with at least a part of the path. 4. The variable conductance heat pipe according to claim 3, wherein the insert is a plate or a wire mesh. The variable conductance heat pipe according to claim 3 or 4, further comprising a spacer for preventing the insert from coming into close contact with the inner wall of the sealed container. 6. The variable conductance heat pipe according to claim 2, wherein the insert has a portion having a large cross-sectional area. 3. The variable conductance heat pipe according to claim 2, wherein the rod is eccentrically inserted into the sealed container. 2. The variable conductance heat pipe according to claim 1, wherein a spiral thin wire is provided along the inner wall of the sealed container. The variable conductance heat pipe according to claim 1, wherein a part of the inner wall of the sealed container is subjected to a treatment for improving water conductivity. 10. The variable conductance heat pipe according to claim 9, wherein a concave portion and a convex portion are provided on a part of the inner wall of the sealed container so that the convex portion extends in the axial direction. 2. The variable conductance heat pipe according to claim 1, wherein a part of the inner wall in the cross section of the sealed container is deformed and the deformed part forms a part having good water conductivity. 2. The variable conductance heat pipe according to claim 1, wherein the heat source is a semiconductor laser.

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