JPS6152919B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat transfer device using a magnetic fluid as a heat transfer medium.

Heat pipes have been known as heat transfer devices that transfer heat by storing a liquid heat transfer medium in a closed container. The container is lined with a porous material with excellent capillary action such as compact metal or metal fiber, and a heat transfer medium such as water or Freon is housed inside the container, and the pressure inside the container is reduced. When the heating section, which is one end of the sealed container, is heated, the heat transfer medium evaporates and vaporizes, and the vapor pressure at the heating section increases, causing the vaporized heat transfer medium to move to the heat dissipation section, which is the other end of the sealed container, where the pressure is lower. The liquefied heat transfer medium is condensed and liquefied in this heat dissipation section to dissipate heat, and then the liquefied heat transfer medium is returned to the heating section by Uyck's capillary phenomenon, and the above cycle is repeated to effect heat transfer. However, in the conventional configuration described above, it is necessary to securely fix the wick to the sealed container with the inner lining, and it is also necessary to sufficiently reduce the pressure inside the sealed container. There was a problem with poor heat transfer efficiency due to the repeated heating evaporation and heat dissipation condensation of the heat medium.

The present invention has been made in view of the above circumstances, and its object is to use a magnetic fluid as a heat transfer medium and to provide a permanent magnet that applies a magnetic field to control the movement of the magnetic fluid. It is an object of the present invention to provide a heat transfer device that is easy to manufacture, inexpensive, and capable of improving heat transfer efficiency.

A first embodiment of the present invention will be described below with reference to FIG.

Reference numeral 1 denotes a closed container, which is formed into a long cylindrical shape with both ends closed with copper or aluminum, and the upper end, which is one end, is connected to the heating section 2.
The other end, the lower end, is used as a heat dissipation section 3. 4 is a magnetic fluid that serves as a heat transfer medium. This was researched and developed by the National Aeronautics and Space Administration under the original name "Ferrofluid," and is made by suspending ferromagnetic fine particles such as ferrite with a size of about 100 Å in water or an organic solvent. It is in the form of a colloidal solution, and its magnetizing power decreases as the temperature rises. A predetermined amount of the magnetic fluid 4 is contained in the sealed container 1, for example, an amount that substantially fills the heat dissipation section 3. Reference numeral 5 denotes a permanent magnet for forming a magnetic field on the side of the heating section 2 of the sealed container 1; It has a tapered shape that gradually becomes smaller in diameter as it goes toward. The permanent magnet 5 is arranged so as to surround the outer periphery of the closed container 1, and is positioned so that its upper end substantially coincides with the upper end of the heating section 2. As a result, the inner circumferential surface of the permanent magnet 5 gradually approaches the outer circumferential surface of the sealed container 1 as it goes upward, and therefore, the magnetic field of the permanent magnet 5 becomes stronger as it goes upward. This results in the formation of a magnetic field like this. In this case, the Curie point, which is the magnetic transition temperature, of the permanent magnet 5 is set to be higher than the Curie point of the magnetic fluid 4. In other words, the magnetic fluid 4 has a Curie point lower than the Curie point of the permanent magnet 5. It is set as follows.

Next, the operation of this embodiment having the above configuration will be explained. For example, when the heating section 2 of the sealed container 1 is not heated, the magnetic fluid 4 in the sealed container 1 is attracted upward along the inner peripheral surface of the sealed container 1 by the magnetic force of the permanent magnet 5, and Since the magnetic field formed by the permanent magnet 5 is set to become stronger as it goes upward, the magnetic fluid 4 is attracted and held by the heating section 2 portion. In this state, when the heating section 2 of the closed container 1 is heated by an appropriate heating means, the magnetic fluid 4 is heated through the peripheral wall of the heating section 2 and accumulates heat, and the magnetic fluid 4 When the temperature of the fluid 4 exceeds the Curie point of the magnetic fluid 4, the magnetic attraction force no longer acts on the magnetic fluid 4, and the magnetic fluid 4 falls under the action of gravity and moves to the heat dissipation section 3. . As a result, the heat accumulated in the magnetic fluid 4 is released to the outside from the peripheral wall of the heat radiating section 3, and the temperature of the magnetic fluid 4 is lowered. after that,
When the temperature of the magnetic fluid 4 becomes below the Curie point,
Since the magnetizing force of the magnetic fluid 4 is restored, the magnetic fluid 4
is moved upward by the action of the magnetic attraction of the permanent magnet 5 and is held in the heating section 2, where it is heated by the heating means. Thereafter, by repeating the above cycle, the heat given to the heating section 2 of the closed container 1 is transferred to the heat radiating section 3.
will be released to the outside.

As described above, according to this embodiment, the magnetic fluid 4 is contained in the closed container 1, and the permanent magnet 5 is disposed outside the closed container 1 on the side of the heating section 2. The magnetic fluid 4 is controlled to be moved to the upper heating part 2 by the action of the magnetic attraction force 5, and moved to the lower heat radiating part 3 by the action of gravity based on the reduction in magnetization due to the heating of the magnetic fluid 4. Unlike the conventional method, it is not necessary to line the inside of the sealed container 1 with a wick, and there is no need to reduce the pressure inside the sealed container 1. Therefore, the structure is simple and manufacturing is extremely easy. , which can be manufactured at low cost, and because the movement of the magnetic fluid 4 is performed by the action of the magnetic attraction force of the permanent magnet 5 and the action of the gravity of the magnetic fluid 4, it is extremely quick and can be manufactured easily compared to conventional methods. Compared to this, heat transfer efficiency can be significantly improved.

Moreover, according to this embodiment, the permanent magnet 5 is formed into a tapered cylindrical shape whose diameter becomes smaller as it goes upward, so that the magnetic field becomes stronger as it goes toward the upper heating section 2. I decided to form
There is an advantage that the magnetic fluid 4 whose temperature is below the Curie point in the heat dissipation section 3 can be quickly moved upward and can be reliably held in the heating section 2 .

In particular, this embodiment has a great feature in that it can efficiently conduct heat transfer from the top to the bottom, which is structurally difficult with conventional heat pipes.

FIG. 2 shows a second embodiment of the present invention, which differs from FIG. 1 in that a heat source 6 such as a positive temperature coefficient thermistor is provided in the heating section 2 of the closed container 1. , there is an advantage that the magnetic fluid 4 can be heated simply and effectively.

FIG. 3 shows a third embodiment of the present invention, and the difference from FIG. 1 is that heat absorption fins 7 and 8 and heat radiation fins protrude inwardly and outwardly from the heating section 2 and heat radiating section 3 of the closed container 1, respectively. 9, 10, and 11 are provided in a protruding manner. According to this, the heating effect and the heat radiation effect are good, and the heat transfer efficiency can be further improved.

FIG. 4 shows a fourth embodiment of the present invention, and the differences from FIG. 1 will be described below. Reference numeral 12 denotes a sealed container used in place of the sealed container 1, which is formed into a tapered cylindrical shape that closes both the upper and lower ends and becomes progressively thicker or larger in diameter as it goes upward, and the upper end is heated. The portion 2 and the lower end portion serve as a heat radiating portion 3, and a magnetic fluid 4 is housed inside. 1
A permanent magnet 3 is used in place of the permanent magnet 5, and is formed into a cylindrical shape having a height approximately two-thirds the height of the closed container 12. The permanent magnet 13 is arranged so as to surround the outer periphery of the closed container 12 so that its upper end substantially coincides with the upper end of the heating section 2 . As a result, the magnetic force acting from the permanent magnet 13 on the magnetic fluid 4 moving upward along the inner circumferential surface of the closed container 12 increases as it goes upward.
Therefore, the permanent magnet 13 forms an apparently upwardly strong magnetic field with respect to the magnetic fluid 4, and the same effect as in the first embodiment can be obtained.

FIG. 5 shows a fifth embodiment of the present invention, and the differences from FIG. 1 will be described below. That is, the closed container 1 is arranged in an inclined state with the heating section 2 facing upward, and therefore, the peripheral wall thereof is divided into an upper wall 1a and a lower wall 1b. A permanent magnet 14 is used in place of the permanent magnet 5. Like the permanent magnet 5, this permanent magnet has a tapered cylindrical shape whose diameter gradually increases upward, and its upper end is connected to the closed container 1. It is arranged in an inclined manner so as to substantially coincide with the upper end and surround the outer periphery of the closed container 1. Therefore, the peripheral wall of the permanent magnet 14 is also divided into an upper wall 14a and a lower wall 14b, and in this case, as the inner peripheral surface of the permanent magnet 14 as a whole goes upward, the closed container 1 In particular, the inner surface of the upper wall 14a is closer to the outer surface of the upper wall 1a at a smaller distance than the lower wall 14b is closer to the outer surface of the upper wall 1b. It is set as follows. As a result, a stronger magnetic force acts on the magnetic fluid 4 moving upward along the inner peripheral surface of the sealed container 1 from the permanent magnet 14 as it goes upward, but in this case, gravity acts strongly. Lower wall 1 where gravity does not act so strongly on magnetic fluid 4 moving upward along upper wall 1a
A stronger magnetic force acts on the magnetic fluid 4 moving upward along the direction b, and therefore the magnetic fluid 4
can be moved smoothly and quickly to the heating section 2, and substantially the same effect as the first embodiment can be obtained.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, but can of course be implemented with appropriate modifications within the scope of the gist.

As explained above, the present invention accommodates a magnetic fluid in a sealed container with one end as a heating section and the other end as a heat radiation section, and a magnetic field becomes stronger as it goes toward the heating section outside of the sealed container. A permanent magnet set as follows is arranged, and the Curie point of the magnetic fluid is set lower than that of the permanent magnet.
Unlike conventional methods, there is no need to line a sealed container with heat wick, and there is no need to reduce the pressure inside the sealed container.It is easy and inexpensive to manufacture, and has the excellent effect of improving heat transfer efficiency. It is possible to provide a heat transfer device that performs.

[Brief explanation of the drawing]

1, 2, 3, 4 and 5 are longitudinal sectional views showing first, second, third, fourth and fifth embodiments of the present invention, respectively. In the drawing, 1 is a closed container, 2 is a heating section, 3 is a heat radiation section, 4 is a magnetic fluid, 5 is a permanent magnet, 6 is a heat source, 7
and 8 are heat absorption fins, 9 to 11 are heat radiation fins,
12 is a closed container, and 13 and 14 are permanent magnets.

Claims (1)

[Scope of Claims] 1. A sealed container with a heating section at one end and a heat radiation section at the other end, a magnetic fluid contained in the sealed container, and a magnetic fluid disposed outside the sealed container and connected to the heating section. 1. A heat transfer device comprising: a permanent magnet configured to have a stronger magnetic field as it goes toward the magnetic fluid, wherein the magnetic fluid has a Curie point lower than the Curie point of the permanent magnet. 2. Claim 1, characterized in that the closed container is arranged such that the heating section is on the upper side.
Heat transfer device as described in Section. 3. The heat transfer device according to claim 1 or 2, wherein a heat source is built in the heating section of the closed container. 4. The heat transfer device according to claim 1 or 2, wherein the heating part and the heat radiation part of the closed container have heat absorption and heat radiation fins, respectively. 5. The heat transfer device according to claim 2, wherein the permanent magnet is formed so as to approach the closed container as it goes upward. 6. The heat transfer device according to claim 2, wherein the closed container is formed in a tapered shape so as to become thicker toward the top. 7. The sealed container is arranged in an inclined shape with the heating part facing upward, and the permanent magnet is formed in a tapered shape so that it approaches the sealed container as it goes upward and the upper side is closer to the sealed container than the lower side. The heat transfer device according to claim 1, characterized in that: