JPS6136694A - Complex wick heat pipe - Google Patents

Abstract

PURPOSE:To obtain a complex wick heat pipe having a large heat transport quantity and a small heat resistance at the top heating by forming at least a part of a condensing part (cooling part) in the complex wick heat pipe into only a groove. CONSTITUTION:A groove 2 extending axially is formed integrally with a vessel 1 in the inner surface of the heat pipe vessel 1. A metal wire 3 is wound around the inner surface of the groove 2 except a cooling portion (condensing portion) 5. When a heating part 4 is heated, the working liquid within the wick boils up and forms a vapor. The vapor moves to the cooling part (condensing part) at a high speed, wherein the vapor condenses at the wall surface of the groove 2 and returns to the original liquid and emits heat. The condensed liquid reaches the end portion 3' of the wire net by the capillary tube force of the groove 2. The working liquid returns to the heating part by the strong capillary force of the wire net, and is again boiled up and forms a vapor. Thus, similar operations are repeated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field] The present invention relates to heat pipes, particularly composite wick heat pipes.

[Conventional technology]

The inside of a pipe-shaped container is degassed, and an evaporative liquid in an amount of several to several tens of percent of the internal volume is sealed therein as a working fluid.
Furthermore, so-called heat pipes, in which a porous or microporous material such as a wire mesh is arranged as a wick on the inner wall of a container to promote circulation of the working fluid, are used in various technical fields.

Among them, so-called composite wick types that use a group and porous wick materials such as nets, fiber bundles, and sintered metals are characterized by the small pressure loss of the group wick and the large conduit pressure of other wick materials. This combination has the advantage that both the angle of inclination and the amount of heat transport are large in the top heat.

However, due to the presence of a wick material such as a net, the thermal resistance is especially high in the cooling section (condensing section), and the thermal resistance of the entire heat pipe is about 2 to 4 times that of a group wick heat pipe. There are drawbacks.

[Problem that the invention seeks to solve]

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved composite wick heat pipe that eliminates the drawbacks of the prior art described above and has a large amount of heat transport at top heat and low thermal resistance.

[Means for solving problems]

In order to achieve the above object, in the present invention, at least a part of the condensing section (cooling section) in the composite wick heat pipe is made into a group only.

〔Example〕

FIG. 1 shows an embodiment of a composite wick heat pipe according to the present invention.

On the inner surface of the heat pipe container 1, a group 2 extending in the axial direction is formed integrally with the container 1. However, the inner surface of lever group 2 has a wire mesh 6 except for the cooling part (condensing part) 5.
is wrapped around it.

As a specific example, the container 1 is made of copper and has an outer diameter of 15.91EII.
, the bottom wall thickness was 1.2 mm, and the length was 400 m, and the lengths of the heating section 4 and the cooling section 5 were each 100 mm. Group 2 has a groove width of 0.4 mm, groove depth of 0.6 mm, and 36 grooves.

The trench wire mesh 6 is made by winding two layers of mesh A100 copper screen mesh.

Although not shown, a copper coil spring was inserted inside the wire mesh 3 in order to improve the adhesion between the wire mesh 3 and the group 2. As for the working fluid, 8 mj of pure water was sealed. This is slightly more than the amount that would fill the entire wick with hydraulic fluid.

In the above configuration, its operation is as follows.

When the heating section 4 is heated, the working fluid in the wick boils and turns into steam, which moves to the cooling section 5 at high speed.

In the cooling section 5, the steam condenses on the wall of the group 2, returns to liquid, and releases heat. The condensed liquid then reaches the end 6' of the wire mesh due to group 2 capillary forces. From the wire mesh end 6', the working fluid returns to the heating section due to the strong capillary force of the wire mesh, boils again, becomes steam, and repeats the same operation. In this way, the working fluid boils, vapor transfers, condenses,
By repeating the reflux of the liquid, the liquid flows from the heating section 4 to the cooling section 5.
The heat is transferred over a long distance, acting as a heat pipe.

Figure 2 shows the heat transfer performance measurement method for obtaining experimental data.

Heating was carried out by uniformly wrapping the heater 7 around the heating section of the heat pipe 1, and cooling was carried out by attaching a water cooling jacket to the cooling section and flowing water through it. The parts other than the cooling part were insulated with glass wool 9. The temperature measurement points of the heat pipe 1 are heating section 11 and 12, insulation section 16, and cooling section 14 and 1.
It was given a score of 5.

The tilt angle is the angle that the heat pipe axis makes with the horizontal, and the clockwise rotation is negative (top heat side).

In addition, the container dimensions and group dimensions of the samples used in the experiment.

The wire mesh and the like are the same as those in the specific example of the present invention described above.

FIG. 6 shows the relationship between the tilt angle and the maximum heat transport amount based on experimental results.

The maximum heat transport amount of the product of the present invention is slightly inferior to that of a conventional composite wick at a negative angle (on the top heat side), but is significantly superior to that of a composite wick of the present invention.

Table 1 shows the thermal resistance of the heat pipe at a heater power of 400 W.

Table 1 As is clear from Table 1, in the conventional composite wink heat pipe, the influence of the thermal resistance of the cooling section is large, whereas the total thermal resistance of the product of the present invention is slightly lower than that of the group heat pipe. It's just big and loud.

In the embodiment described above, a wire mesh was used as the wick material to obtain a large capillary force by disposing it on the inner surface of the group, but this may also be a metal fiber bundle, a porous sintered metal, or the like.

Further, for example, the wire mesh wick need not be limited to being on the entire surface except for the cooling section, and the metal end 6' may extend halfway into the cooling section, or conversely, the wire mesh wick may extend halfway into the heat insulating section 6. The arrangement may be such that the portion 6' is located.

The point is that only the group can receive the reflux of the working fluid from the condensing part to the boiling part, and then the capillary force of the wick other than the group can be used from the middle. Therefore, it can naturally be applied to a type in which the heating section is located in the center and the cooling sections are located at both ends.

Furthermore, the shape of the heat pipe container is not limited to having a circular cross section.

〔Effect of the invention〕

As described above, according to the present invention, there is an advantage that a heat pipe can be obtained which has a maximum heat transport amount as large as that of a conventional composite wick heat pipe and a heat pipe that has a thermal resistance as small as a group wick heat pipe.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view showing an embodiment of a heat pipe according to the present invention, Fig. 2 is an explanatory diagram of a method for measuring heat transfer performance of a heat pipe, and Fig. 6 is a performance measurement result of an embodiment of the present invention. This is a graph showing. 1; heat pipe container, 2; group, 6; wire mesh, 6'
wire mesh end, 4; heating section, 5; cooling section.

Claims (2)

[Claims] (1) A composite wick in which a groove is formed on the inner surface of the heat pipe container and extends in the axial direction integrally with the container, and porous or microporous wicks such as nets, fiber bundles, and sintered metal are placed inside the groove. A composite heat pipe characterized in that at least a part of the inner surface of a cooling part is made of only a group heat pipe. (2) The composite wick heat pipe according to item 1 above, wherein the wick disposed inside is a wire mesh.