WO2006059622A1

WO2006059622A1 - Magnetic convection heat circulation pump

Info

Publication number: WO2006059622A1
Application number: PCT/JP2005/021956
Authority: WO
Inventors: Shinichi Nakasuga; Hironori Sahara; Kenji Higashi
Original assignee: Da Vinci Co., Ltd.; The University Of Tokyo
Priority date: 2004-12-03
Filing date: 2005-11-30
Publication date: 2006-06-08
Also published as: EP1832828A1; JP4507207B2; US20080264068A1; EP1832828B1; JPWO2006059622A1; EP1832828A4; ATE523747T1

Abstract

A magnetic convection heat circulation pump, wherein magnets are disposed inside a magnetic filed flow passage for passing a magnetic fluid therein or on a part of the inner wall surface of a circulation flow passage in a magnetic pump thermally joined to a heat receiving part. The magnetic fluid is driven since a magnetic force is directly applied to the magnetic fluid and a large temperature gradient is produced between the heat receiving part and the magnetic pump due to a difference between a heat quantity transferred from the heat receiving part indirectly to the magnetic pump and the heat quantity of the magnetic fluid led into the magnetic pump.

Description

Specification

Magnetic convection heat circulation pump

Technical field

TECHNICAL FIELD [0001] The present invention relates to an element that transfers thermal energy, and more particularly, to a magnetic convection heat circulation pump that utilizes the magnetic flux density of a magnetic field and the temperature characteristics of a saturated magnetic field of a magnetic material.

Background art

[0002] Among heat transfer elements, heat transfer elements using magnetic convection due to the temperature dependence of the saturation magnetization of a magnetic fluid in a magnetic field have been devised for a long time. In addition, the non-uniform distribution of the magnetic substance in the dispersion medium and the large remanent magnetism due to the coating accuracy of the surfactant that coats the magnetic substance and the like have hindered magnetic convection and hindered commercialization.

[0003] In recent years, solutions to the above-described problems have also been attempted. For example, as disclosed in JP-A-10-231814 and JP-A-3-102804, paramagnetic substances such as gas, As a means for transferring a magnetic fluid or the like having a very small remanent magnetic field, an apparatus utilizing a temperature dependency of a saturated magnetic field by arranging a heater in the vicinity of a magnetic field has been developed.

[0004] However, when a heat input unit such as a heater is configured, the temperature of the material itself to be transferred rises, so the usage is limited. There was a problem that it was not suitable for use.

[0005] Furthermore, a method of arranging the electromagnets at predetermined intervals and sequentially moving the magnetic field is disclosed, but the control of the electromagnets and electrical wiring are required, and the apparatus becomes complicated and expensive. Disclosure of the invention

[0006] Therefore, the present invention takes a large temperature gradient of the magnetic fluid in the magnetic field by using the magnetic flux density of the magnetic field and the temperature characteristics of the saturation magnetization of the magnetic material without using an electric drive source, and saturates. An object of the present invention is to provide a magnetic convection heat circulation pump capable of efficiently converting to power by causing a difference in magnetic value.

[0007] In order to achieve the above-mentioned object, according to the present invention, magnetic force acts directly by arranging a magnet so as to form a part of a circulation flow path or a circulation flow path that passes through a heat receiving portion. The magnet Provided is a magnetic convection heat circulation pump that takes advantage of the temperature dependence of the saturation magnetization of a magnetic fluid in the magnetic field produced by the temperature gradient caused by the heat input from the heat receiving section, causing continuous magnetic convection of the magnetic fluid.

[0008] The magnetic convection heat circulation pump of the present invention has a structure that is very structured in that the heat input of the heat receiving portion serves as an operating source, and magnetic fluid causes magnetic convection by the magnetic field to circulate between the heat receiving portion and the heat radiating portion. The operation is continued as long as there is a temperature difference between the heat receiving part and the heat radiating part, and if the temperature difference further widens, the circulation speed increases and a large amount of heat can be easily carried. . Brief Description of Drawings

FIG. 1 is a schematic diagram showing a magnetic convection heat circulation pump when a magnet is arranged in a circulation flow path.

FIG. 2 is a schematic view illustrating the arrangement of magnets.

FIG. 3 is a schematic diagram showing a magnetic convection heat circulation pump when a magnet is arranged in a circulation channel.

FIG. 4 is a schematic diagram when magnets are arranged in a square shape.

FIG. 5 is a schematic diagram when a magnet and a magnetic body are arranged in a U-shape.

FIG. 6 is a schematic diagram showing a magnetic convection heat circulation pump when a magnet is arranged in a circulation channel.

FIG. 7 is a schematic diagram showing a magnetic convection heat circulation pump when a magnet is arranged in a circulation channel.

FIG. 8 is a schematic diagram showing a magnetic convection heat circulation pump when a magnet is arranged on a part of the inner wall surface of the circulation channel.

FIG. 9 is a schematic diagram showing a magnetic convection heat circulation pump when a magnet is arranged on a part of the inner wall surface of the circulation channel.

FIG. 10 is a perspective view partially seen through a magnetic convection heat circulation pump with a thin pump section.

FIG. 11 is a schematic diagram showing the arrangement of magnets when fixed to a yoke.

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] In the present invention, nickel plating or the like is formed in the magnetic field flow path of the magnetic fluid or a part of the inner wall surface of the flow path. A surface-treated magnet is disposed, and a part or all of the inner wall surface of the magnet or the circulation channel is coated with a surfactant of the same type as that of the surfactant coated with the magnetic substance of the magnetic fluid. By coating, a magnetic field acts directly on the magnetic fluid, and the flow path resistance is also reduced.

[0011] Further, as the magnetic material, an alloy of manganese, zinc, and iron oxide with high saturation magnetism temperature dependence is adopted, and the average particle size of the alloy is about 10 nm, preferably 6 nm, and more preferably. By using lnm, we realized an efficient magnetic convection heat circulation pump with minimal residual magnetism.

[0012] Furthermore, the heat receiving section and the magnetic pump are formed of materials having different thermal conductivities, and a configuration is adopted in which the magnetic field flow paths are mutually shared.

Example 1

[0013] One embodiment of a magnetic convection heat circulation pump according to the present invention will be described below with reference to Figs.

[0014] In FIG. 1, a circulation channel (3) that circulates between the heat receiving unit (1) and the heat dissipation unit (2) is arranged, and the magnet N pole is disposed in the circulation channel (3) in parallel with the extending direction. An example in which (4) and S pole (5) are arranged is shown below. The circulation channel (3) is filled with magnetic fluid, and if there is heat input to the heat receiving part (1), the temperature of the magnetic fluid in the heat receiving part (1) rises, and the heat receiving part (1) and the heat radiating part A temperature gradient occurs between the magnetic fluid held in (2) and the magnetic fluid on the heat receiving part (1) side where the magnetic reluctance is reduced is pushed out by the magnetic fluid on the heat radiating part (2) side, An example of magnetic convection causing heat transfer

[0015] In such a configuration that causes circulation, the magnetic force of the magnet is directly transmitted to the magnetic fluid, so that the efficiency is good, and even if it is used for heat dissipation of an electronic device or the like, the influence of the leakage magnetic flux is remarkably reduced. .

[0016] The ferrofluid of the present invention can be used as long as it has a magnetic particle as a magnetic material and is dispersed in an appropriate dispersion medium. The magnetic particles are preferably used as a powder having an average particle size of less than 30 nm, more preferably 1 nm to lOnm.

[0017] The magnetic substance used in the present invention is particularly preferably an alloy of a divalent transition metal and iron oxide, which is preferably an alloy having a high temperature dependency. [0018] The magnetic material is preferably coated (coated) with a surfactant. The surfactant used for coating is preferably a surfactant having an ionic characteristic such as a cationic surfactant or an anionic surfactant. Due to the repulsive force of these surfactants, the magnetic material was uniformly distributed in the dispersion medium. As a result, the residual magnetization can be reduced and the flow path resistance can be greatly reduced.

[0019] More preferably, a part of or all of the surface that contacts the magnetic fluid of the circulation channel or the magnet disposed in the circulation channel has the same kind as the ionic characteristics of the surfactant obtained by coating the magnetic material. By coating with a surfactant, the influence of residual magnetism can be further reduced, and the flow resistance can be further reduced.

[0020] Furthermore, by adopting a highly temperature-dependent alloy as a magnetic material, a large change in the saturation magnetization value due to temperature becomes a large power in the magnetic field, and the efficiency as a pump for magnetic convection is greatly improved. In this example, a force using an alloy of manganese, zinc and iron oxide (lZ2Znl / 2MnFe 2 O 3) is not limited to this.

twenty four

The temperature dependence of the saturation magnetism of the magnetic material is the same as or younger than lZ2ZnlZ2MnFeO

twenty four

Is preferably an alloy of a divalent transition metal and iron oxide, which exhibits ferromagnetism and has a greater temperature dependence.

[0021] A magnetic ionic liquid can also be used as the magnetic fluid of the present invention. The magnetic ionic liquid is preferably a combination of the typical magnetic anion salt salt of iron and ferric ion and the cation 1-butyl 3-methylimidazole.

FIGS. 2 to 4 show the arrangement of the magnets of Examples 1 to 3. Figure 2 shows an example in which a strong magnetic field magnet (4) (5) is placed on the heat-receiving side and a weak magnetic field magnet 2 (4b) (5b) is placed on the heat dissipation side to create a magnetic field gradient. Indicated. Fig. 3 shows an example in which magnets are arranged in the circulation channel so as to face each other. FIG. 4 shows an example in which the magnets in the circulation channel (3) are arranged in a square shape so that the magnets are narrower on the heat receiving part (1) side. In this way, by creating a strong magnetic field on the heat-receiving part side, the magnetic material having a low temperature and a strong magnetic repulsive force can easily move to a strong magnetic field.

FIG. 5 shows an example of a magnet in which a ferromagnetic circuit (10) force, for example, iron or the like is formed into a U-shape and magnets are arranged on opposite surfaces to constitute a magnetic circuit. With this configuration, the leakage flux is very The magnetic force between the N pole (4) and the magnet S pole (5), which are opposed to each other, becomes stronger.

Further, FIG. 6 shows a configuration of a magnetic heat pump that forms a plurality of circulation paths and efficiently circulates with a smaller amount of magnetic fluid than the configuration shown in FIG. According to Fig. 6, the magnetic field channel (6) is formed along the magnetic field lines of the magnets (4) and (5) arranged in the heat receiving part (1) in the circulation channel of the first channel (7). However, it may be arranged in the path of the second channel (8) and the third channel (9), and the magnetic field channel along the magnetic flux on both sides of the magnet (4) (5). (6) may be formed.

Example 2

Example 2 will be described with reference to FIG. The heat receiving part (1) and the heat radiating part (2) are connected by a circulation channel (3). If the heat receiving part (1) and the heat radiating part (2) are made of a flexible material such as a flexible pipe or a resin pipe as the constituent material of the circulation flow path (3), the heat receiving part (1) and the heat radiating part (2) are not limited to a straight arrangement, but are optional. It becomes possible to arrange | position in the position of.

Example 3

Example 3 will be described with reference to FIG. The magnetic convection heat circulation pump has a configuration in which ring-shaped magnets (4a) and (5a) are arranged in the pipe (12) connecting the heat receiving part (1) and the heat radiating part (2). If such a configuration is adopted, the heat receiving part (1) and the heat radiating part (2) need only be one common part, and the joining part (11) can be easily detached without leakage due to magnetic joining. This is also easy to use when filling magnetic fluid.

[0027] The method of fixing the magnets arranged in each of the above-described embodiments is not particularly limited. The magnet is fixed so as to be movable by fitting into a guide groove or the like, or fixed and fixed by adhesion or the like. It may be a method to do so.

[0028] Similarly, it is preferable to use materials with high thermal conductivity, such as copper, aluminum, and graphite, as materials for the heat receiving portion (1) and the heat radiating portion (2). More preferably.

Example 4

[0029] Example 4 will be described below with reference to Figs. In the present embodiment, the part constituted by the magnetic field flow path (6) and the magnet (13) is called a magnetic pump (14). As an example, in FIG. 9, in order to prevent the backflow of the magnetic fluid, the width of the end of the magnetic flow path (6) on the heat receiving part (1) side is gradually reduced, and the magnetic flow path (6 Different heat transfer to share) A magnetic convection heat circulation pump is shown in which a heat receiving part (1) made of a material with conductivity and a magnetic pump (14) are thermally connected. In the magnetic field channel (6), a magnet (13) is installed and formed integrally.

[0030] In addition, the magnetic field flow path (6) and the circulation flow path (3) of the heat receiving part (1) dissipate heat through the connection circulation flow path (3) made of fluorine-based resin, such as PFA. When the heat receiving part (1) is connected to the part (2) and there is heat input, a part of the magnetic field channel (6) is directly input with heat. However, heat is indirectly transmitted to the magnetic pump (14) and is made of a material having a smaller thermal conductivity than the heat receiving part. Therefore, compared to the heat receiving part (1). As a result, the amount of heat transferred is small, resulting in a large temperature gradient in the magnetic field flow path (6), and the magnetic fluid with a high temperature and a low saturation magnetic field value has a high saturation magnetic field value with a low temperature. Circulation is started by being pushed by the magnetic fluid. For example, in order to cause such a circulation, it is sufficient that there is a difference in thermal conductivity between aluminum and a resin material. When the circulation of the magnetic fluid begins, the magnetic fluid that is not heat input into the magnetic pump (14) flows from the heat radiating section (2) due to the generated pressure, and the temperature difference further increases. As a result, the circulation speed is increased and more heat can be transferred.

[0031] In this embodiment, the magnetizing direction of the magnet (13) is not particularly shown, but it may be either the width direction or the longitudinal direction. For example, when a magnet magnetized in the longitudinal direction is used, the place where the temperature difference occurs is moved to a place where the magnetic field from the heat radiating part (2) of the magnetic pump (14) is strong when the heat input is large. When the input is small, the magnet moves to the vicinity of the center of the magnet (13) having a weak magnetic field, so that a configuration that keeps the temperature of the heating element constant can be realized even if a magnet (13) suitable for the application is used.

[0032] Although not shown, in order to reduce the shear stress of the flow path and prevent aggregation of the magnetic fluid, a part or all of the surface of the circulation flow path in contact with the magnetic fluid may be oil repellent and repellent made by Asahi Glass Co., Ltd., for example. Coat with an oil-repellent coating material such as Cytop, the product name that has aqueous properties, or the same kind of surfactant as the ionic characteristics of magnetic fluid, that is, magnetic fluid is coated with a force thione-based surfactant. In this case, it is preferable to coat with the same cationic surfactant.

[0033] In this embodiment, the magnetic field flow path (6) is shared by the heat receiving section (1) and the magnetic pump (14). The heat receiving part (1) and the magnetic pump (14) have good thermal conductivity! If it is possible to connect them thermally with metal, etc., the magnetic flow path (6) can be shared. good.

[0034] Further, FIG. 10 shows a configuration in the case where the heat receiving portion (1) and the magnetic pump (14) are made of a material having the same thermal conductivity. By making the thickness of the material forming the magnetic pump (14) thinner than the heat receiving part (1) for the heat input from the heat receiving part (1), the heat transfer coefficient is reduced and the thermal conductivity is reduced. The same effects as when using different materials can be obtained.

FIG. 11 shows an example in which a magnetic circuit is configured. The magnet (13) is arranged so that the north and south poles face each other, and is fixed by a yoke (15). With this configuration, not only can a very strong magnetic field be obtained, but also the magnetic field flow path (6) is located between the faces where the N and S poles face each other. The obstruction is obstructed and the pump performance is improved. Furthermore, it is possible to significantly reduce the leakage flux from the magnetic heat pump.

[0036] According to the present invention, the magnetic heat pump of the present invention has a large heat transfer capability per unit area, and can be freely arranged by connecting the heat receiving section and the heat radiating section with a flexible resin pipe. Furthermore, the configuration of the pump unit can be made very small. For this reason, electronic devices are becoming more compact and the power consumption density of electronic components increases. Therefore, it is necessary to transfer heat from a small space to a place where it comes into contact with the outside air to dissipate heat. It can be used for heat transfer and heat dissipation of optical elements such as parts and laser diodes.

[0037] Further, according to the present invention, since the magnetic heat pump of the present invention does not use electricity, the heat prevention measures for unmanned facilities, the use of solar heat indoors in cold regions, It can be applied to various uses such as heat transfer during reuse.

Industrial applicability

[0038] Further, according to the present invention, the magnetic fluid used in the magnetic heat pump of the present invention has low volatility, so that heat transfer is possible even under harsh conditions such as in space, such as in space stations. It can also be used as solar heat recovery means or heat transfer means in an artificial satellite.

Claims

The scope of the claims

[1] A heat circulation pump having a heat receiving section, a heat radiating section, and a circulation channel that circulates between the heat receiving section and the heat radiating section, wherein a magnet is provided in the circulation channel or a part of an inner wall surface of the circulation channel. A magnetic convection heat circulation pump having an arranged structure and using a magnetic fluid as a circulating working fluid.

[2] heat receiving part;

A magnetic pump thermally connected to the heat receiving unit;

Heat dissipation part, and

A heat circulation pump having a circulation passage for connecting the heat receiving portion and the magnetic pump and the heat radiating portion in fluid communication,

The magnetic pump circulation channel forms a part of the magnetic field channel by arranging a permanent magnet in the circulation channel or by forming a part of the inner wall surface of the circulation channel with the permanent magnet. A magnetic convection heat circulation pump having a structure as described above, wherein a magnetic fluid is used as a circulation working fluid flowing in the circulation flow path.

[3] The magnetic convection heat circulation pump according to claim 1 or 2, wherein the circulation flow path is constituted by a pipe line.

4. The magnetic convection heat circulation pump according to claim 1 or 2, wherein the magnetic substance of the magnetic fluid has an average particle size of less than 30 nm and is an alloy of a divalent transition metal and iron oxide.

5. The magnetic convection heat circulation pump according to claim 1 or 2, wherein the magnetic fluid is a magnetic ionic liquid or a magnetic ionic liquid that has a cation force with a magnetic anion.

6. The magnetic convection heat circulation pump according to claim 1 or 2, wherein the magnet is disposed so as to detachably connect the heat receiving portion and the heat radiating portion.

7. The magnetic convection heat circulation pump according to claim 2, wherein the heat receiving part and the magnetic pump share a magnetic field flow path.

8. The magnetic convection heat circulation pump according to claim 2, wherein the heat receiving part and the magnetic pump are made of materials having different thermal conductivities.

[9] A part of the surface in contact with the magnetic fluid of the circulation channel or the magnet disposed in the circulation channel The magnetic convection heat circulation according to claim 1 or 2, wherein the magnetic convection thermal circulation according to claim 1 or 2 is coated with a surfactant of the same type as that of the surfactant coated with a magnetic substance of the magnetic fluid. pump.

3. A part or all of the circulation channel or a surface of the magnet disposed in the circulation channel in contact with the magnetic fluid is coated with a coating material having oil repellency. Magnetic convection heat circulation pump as described.