JPS601553B2 - long heat pipe - Google Patents

Description

[Detailed description of the invention] This invention relates to heat pipes.

Conventionally, as shown in Fig. 1, a heat pipe has a structure in which a porous wick 2 is attached to the inner surface of a circular tube 1 whose both ends are sealed, and a working fluid is sealed inside the circular tube 1. However, in such a heat pipe, the working fluid is evaporated by the heat Q given to the evaporator part E from an external heat source, and the vapor pressure in that part increases, causing the steam to flow to the condensing part C, where it is The working fluid is condensed and liquefied by transferring the latent heat to an appropriate heat absorbing source, and the working fluid condensed and liquefied in the condensing section C is condensed and liquefied in the evaporating section E due to the capillary pressure generated by the evaporation of the working fluid in the evaporating section E. In this way, the working fluid circulates while repeating evaporation and condensation, and as a result, the latent heat of the working fluid is transferred to an external heat source (
Alternatively, heat can be transported from a heat absorbing source (or a low-temperature region) to a heat-absorbing source (or a low-temperature region). However, in the above-mentioned heat pipe, if sufficient capillary pressure and associated pumping pressure are obtained, the pumping action causes the liquid phase working fluid to reflux, allowing continuous heat transport. There is a limit to the pumping pressure that acts to recirculate liquid-phase working fluid based on pressure, and in particular, it is difficult to reflux liquid-phase working fluid against gravity by standing up a heat pipe or tilting your face. For example, if a conventional heat pipe with a single continuous wick 2 is placed vertically, the pumping pressure will cause the working fluid to resist gravity. The height that can be refluxed is 20 to 40 cm.
cm is the limit, therefore, the evaporation section E and the condensation section C
If the heat pipe is installed so that the height difference between the wick 2 and the wick 2 becomes larger than that, the liquid phase working fluid will not flow back and the wick 2 will partially dry up, making it impossible to transport heat.

Furthermore, as mentioned above, there is a limit to the working pressure of the pump 70 that acts to reflux the working fluid, so even if the heat pipe is installed horizontally, the distance over which the liquid-phase working fluid can be refluxed is limited. The maximum length is 30 to 50 skins, and if the heat pipe is made longer than that, the wick 2 will partially dry out, making it impossible to transport heat. In any case, since the conventional heat pipe has a single continuous wick 2,
The distance or height over which heat can be transported, that is, the length of the heat pipe itself, is limited by capillary pressure, and it has not been possible to make it long. Therefore, the inventors of the present invention divided the inside of a sealed tubular container 3 into a large number of sealed chambers 5 by partition plates 4, and installed a wick 6 in each of the sealed chambers 5, as shown in FIG. At the same time, if a working fluid is sealed, and the length of each sealed chamber 5 is set to a length that allows the working fluid to be sufficiently refluxed by the pump action pressure based on capillary pressure, and such sealed chambers 5 are provided in succession,
The length of the heat pipe is not limited by capillary pressure (or pumping pressure), so the sheet pipe can be made longer, and the high temperature section is above and the low temperature section is below, and the difference in height between them is It has been found that heat transport is possible even in large cases.

However, in the heat pipe configured as shown in FIG. 2, heat is transported within each sealed chamber 5 by the working fluid, and heat is transferred between each sealed chamber 5 by heat conduction via the partition wall plate 4. However, since the inner diameter of the container 3 is limited and the partition plate 4 cannot be made very large, depending on the structure of the partition plate 4, the amount of heat conduction may be smaller than the amount of heat transported by the working fluid. This may result in a significant reduction in the heat transport capacity of the heat pipe as a whole. This invention has been made in view of the above circumstances, and an object thereof is to provide a heat pipe that can be made longer without reducing its heat transport ability by making the partition wall member have a special structure. be.

Embodiments of the present invention will be described below with reference to FIGS. 3 to 9.

FIG. 3 is a longitudinal sectional view showing the first embodiment of the present invention, in which the container is a long tubular body made of a metal with high thermal conductivity such as steel or aluminum, and both ends thereof are sealed. is,
Furthermore, partition members 11 are inserted and arranged at predetermined intervals inside the container 10, and a large number of sealed chambers 12 are defined inside the container 10 by these partition members 11.

As shown in FIGS. 4 and 5, the partition wall member 11 is made of a metal with high thermal conductivity such as steel and has a cylindrical shape as a whole, and has a honeycomb structure inside. Among the many pores forming the honeycomb structure, appropriately selected pores are closed at one end (the right end in FIG. 4) and open to the sealed chamber 12 at the other end. These bottom hollow parts 11a are
The other pore adjacent to is closed at the other end (the left end in FIG. 4) to form a bottomed hollow portion 11b that closes into the sealed chamber 12 at one end. Then, the partition wall member 1
1 is inserted into a predetermined location within the container 10, and is crimped and fixed to the inner peripheral surface of the container 10 by shrinking the location of the container 10. Further, a wick 13 is disposed inside each of the sealed chambers 12 along the inner peripheral surface thereof, and a working fluid is sealed in each of the sealed chambers 12.

As the wick 13, a metal mesh, porous sintered metal, or a narrow groove is used, and as the working fluid, an appropriate fluid such as water, ammonia, or nitrogen is used depending on the temperature of the area where the heat pipe is used. is used. Note that the pumping pressure generated in each sealed chamber 12 is determined by the wick 13, the type of working fluid, or the installation mode of the heat pipe, but the length L of each sealed chamber 12 is such that the working fluid in the liquid phase can be pumped at the pumping pressure. The length is set to allow for reflux.

When heat is applied to one end of the heat pipe configured as described above, the working fluid inside the heat pipe evaporates, and the vapor flows to the other end of the sealed chamber 12 to form the partition wall 11. The vapor enters the bottomed hollow portion 11a of the vapor and transfers heat to the working fluid in the adjacent closed chamber 12 via the wall surface separating the bottomed hollow portions 11a and 11b, whereby the vapor is condensed and liquefied.

On the other hand, the working fluid to which heat has been transferred via the partition member 11 evaporates and flows within the sealed chamber 12 to the other end. Similarly, the working fluid in each sealed chamber 12 evaporates and flows toward the other end to transport heat, and each sealed chamber 1
2 by heat conduction through the partition walls 11, thus transporting heat from one end to the other. In this case, the heat conduction area in the partition member 11 is the total surface area of the bottomed hollow portions 11a and 11b and is extremely large, so that conduction loss in the partition member 11 can be reduced. In other words, in conventional heat pipes, when the length exceeds the length limited by the pumping pressure based on capillary pressure, the end on the low temperature side The temperature distribution becomes such that the temperature gradually decreases, making it impossible to transport heat.
In the heat pipe having the above structure, as shown by the solid line in FIG. 6, the temperature decreases slightly due to the thermal resistance of the partition wall member 11.
T, but isothermality is maintained within each sealed chamber 12, so the heat transport capacity of the heat pipe as a whole can be increased, and heat can be transported over long distances. The working fluid condensed and liquefied in the bottomed hollow part 11a flows out from the bottomed hollow part 11a by tilting the heat pipe so that the opening of the bottomed hollow part 11a faces downward. The liquid-phase working fluid permeates into the wick 13, and as a result, the liquid-phase working fluid flows back to the evaporator side via the wick 13. In addition, since the amount of working fluid is usually set so that a certain amount remains as a liquid, by tilting the heat pipe as described above, the working fluid in liquid phase is transferred to the bottomed hollow part on the evaporation part side. Enter 11b. Therefore, in the partition member 11, the bottomed hollow portion 11
Heat exchange continues between the liquid-phase working fluid and the gas-phase working fluid via a and 11b, and as a result, heat can be continuously transported throughout the heat pipe. In addition, each bottomed hollow part 11a, 1 forming the honeycomb structure of the partition wall part village 11
The cross-sectional shape of 1b does not necessarily have to be hexagonal as shown in FIG. 5, but may be triangular or convex as shown in FIG. However, since the partition wall member 11 is easily deformed in the radial direction, when the partition wall member 11 is fixed in the container 10, if the container 10 is contracted, the partition wall member 11 will come into close contact with the inner circumferential surface of the container 10, and therefore the partition wall Fixing of the member 11 and sealing against the inner circumferential surface of the container 10 can be performed simultaneously and easily.

Furthermore, by tightening the inner walls of the bottomed hollow parts 11a and 11b, capillary pressure can be generated in the bottomed hollow parts 11a and 11b. FIG. 8 shows a second embodiment of the present invention, in which the heat pipe has a relatively short tubular body 20.
a are sequentially connected by partition members 21 to form a long tubular container 20 as a whole, and at the same time, the inside of the container 20 sealed by the partition members 21 is defined as a sealed chamber 22, and each of these sealed chambers 22
A wick 23 is disposed therein, and a working fluid is sealed therein.

As shown in FIGS. 8 and 9, the partition member 21 has an annular bottomed hollow portion 21a that opens into the sealed chamber 22 on one side and a closed hole 21a that opens into the sealed chamber 22 on the other side. The annular bottomed hollow portions 21b are alternately formed in the same circular shape. Also in the heat pipe configured as described above, since the heat conduction area in the partition wall member 21 can be set wide, the heat transport capacity can be increased similarly to the heat pipe in the first embodiment. The pipe itself can be made longer.

In addition, in this invention, all closed rooms 12 or 2
It is not necessary to seal the same working fluid in the chambers 2, and as mentioned above, there is a slight temperature drop ΔT between adjacent sealed chambers 12 or 22 due to the thermal resistance of the partition wall member 11 or 21. , a working fluid suitable for the temperature conditions of each sealed chamber 12 or 22 according to the usage conditions of the heat pipe may be appropriately selected and sealed in each sealed chamber 12 or 22, for example, in the sealed chamber 12 or 22 on the high temperature side. fill with water,
Working fluids having lower boiling points may be sequentially filled in the closed chambers 12 and 22 on the low temperature side.

As is clear from the above description, according to the heat pipe of the present invention, partition members are arranged at predetermined intervals in a sealed tubular container to form a large number of sealed chambers, and a wick is disposed in each sealed chamber. A working fluid is sealed in the partition wall, and the partition wall has a large number of small-section bottomed hollow portions that open into one of the sealed chambers on both sides of the partition wall, and a hollow portion with a bottom that opens into the other sealed chamber.
Since the structure has a large number of small-section bottomed hollow parts adjacent to each other and along the axial direction of the container, the liquid phase working fluid can be refluxed through the length of each sealed chamber under the pump action pressure. By setting the length to the desired length, the length of the heat pipe can be maximized without being constrained by the pumping pressure.
Furthermore, since the heat conduction area in the partition wall can be set wide, there is less heat transfer loss in the partition wall member, and therefore, according to the present invention, it is possible to obtain a long heat pipe with high heat transport capacity. be.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway perspective view showing a conventional heat pipe with some parts omitted; Fig. 2 is a partially cutaway perspective view showing an example of a long heat pipe with some parts omitted; FIG. 4 is an enlarged sectional view showing an embodiment of the present invention, FIG. 5 is a view taken along the line V-V in FIG. 4, and FIG.
The figure is a diagram showing the temperature distribution in the longitudinal direction in the long heat pipe of the present invention and a conventional long heat pipe, and FIG. 7 is a schematic diagram showing the pore shape of the honeycomb structure of the partition wall. 8 is a partial sectional view showing another embodiment of the present invention, and FIG. 9 is a partial sectional perspective view showing a partition member thereof. 10, 20... Container, 11, 21... Partition member, 1
1a, 11b, 21a, 21b...bottomed hollow part, 12, 2
2... Sealed room, 13, 23... Uitsuku. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9

Claims (1)

[Claims] 1. A heat pipe in which a large number of airtight chambers are formed by arranging a large number of partition wall members at predetermined intervals inside a sealed tubular container, and a heat pipe is provided in each of these sealed chambers and a working fluid is sealed therein. The partition member has a large number of small cross-section bottomed hollow portions that open into one of the sealed chambers on both sides thereof, and a large number of small cross-section bottomed hollow portions that open into the other sealed chamber. A long heat pipe characterized by being formed along the axial direction and adjacent to each other.