WO2015174423A1

WO2015174423A1 - Cooler and cooling device using same, and cooling method for heating element

Info

Publication number: WO2015174423A1
Application number: PCT/JP2015/063669
Authority: WO
Inventors: 昌司森; 邦人奥山
Original assignee: 国立大学法人横浜国立大学
Priority date: 2014-05-12
Filing date: 2015-05-12
Publication date: 2015-11-19
Also published as: JP6283410B2; JPWO2015174423A1

Abstract

Provided is a cooler that has a simple structure and that has stable and favorable cooling effects. A cooler that uses a boiling system to cool a heating element and that comprises: a container that houses a working fluid; and a cooling member that is provided inside the container so as to contact the working fluid and so as to face the heating element. The cooling member is constituted by a layered structure that comprises: a porous body that is provided on a heating element side; and a working fluid introduction body that is provided on a working fluid side. The porous body comprises: a working fluid supply part that uses capillary action to supply the working fluid to a contact part that contacts the heating element; and a steam discharge part that discharges steam that is generated at the contact part to a working fluid introduction body side. The working fluid introduction body comprises a working fluid introduction part that leads the working fluid to the porous body.

Description

COOLER, COOLING DEVICE USING SAME, AND METHOD OF COOLING HEAT GENERATOR

The present invention relates to a cooler, a cooling device using the same, and a cooling method for a heating element, and more particularly to a boiling-type cooler, a cooling device using the same, and a cooling method for a heating element. is there.

In recent years, in a pressure vessel of a light water reactor as shown in FIG. 1, there is a demand for a cooling mechanism that does not cause melt-through by cooling the bottom of the reactor pressure vessel with water from the outside even if a fuel rod causes a melting accident, As such a cooling mechanism, a boiling cooling system is known.

The boiling cooling method includes a pool boiling method and a forced flow boiling method. Here, a general cooling mechanism of the heating element by the pool boiling method will be described. FIG. 2 shows a conventional pool boiling cooler. The cooler includes a container and a working fluid contained in the container, and the container has a contact portion with a heating element to be cooled. When heat is generated in the heating element and the heat is transmitted to the working fluid through the contact portion, the working fluid existing in the vicinity of the contact portion boils. When steam is generated by boiling, the working fluid is supplied to the contact portion due to the density difference between the gas and the liquid. In this way, the newly supplied working fluid is further evaporated, and heat is removed from the heating element. The pool boiling type cooler is advantageous in terms of compactness and energy saving because it does not require an external power source for circulating the liquid as in the forced flow boiling method.

JP 2009-139005 A

However, if a large heat flux is applied to the contact portion, there is a problem with the conventional pool boiling type cooler. This is shown in FIG. As the heat flux increases, the amount of evaporation of the working fluid increases and the contact portion begins to be covered with steam. When the contact portion is completely covered with steam and becomes dry, and the working fluid is not supplied to the contact portion, the cooling capacity of the cooler is significantly deteriorated. The heat flux in this state is referred to as “limit heat flux”.

The limit heat flux of the cooler by the conventional pool boiling method is about 1000 kW / m ² in the saturated state under atmospheric pressure and water conditions (see Non-Patent Document 1). In order to prevent melt-through at the bottom of the reactor pressure vessel, a limit heat flux of at least about 2000 kW / m ² is required for the cooler.

On the other hand, the present inventor disclosed in JP 2009-139005 A (Patent Document 1) that a porous body is provided between a heating element and water in a cooling container, and water is supplied by capillary action of the porous body. The conventional limit heat flux is drastically improved with a simple structure by supplying the heat generating element and discharging the generated steam into the water in the container. However, in order to more safely prevent melt-through at the bottom of the reactor pressure vessel, it is desired to develop a cooler that further enhances the cooling effect.

An object of the present invention is to provide a cooler having a simple structure and stably having a good cooling effect, a cooling device using the cooler, and a method for cooling a heating element.

As a result of repeated research, the inventor has provided the porous body disclosed in Patent Document 1 on the heating element side, and further overlaps the working fluid on the working fluid side. It has been found that by providing a working fluid introduction body including a working fluid introduction section that leads to a material body, it is possible to provide a cooler that further improves the cooling effect.

That is, an aspect of the present invention is a boiling-type cooler for cooling a heating element, and a container that contains a working fluid, and is in contact with the working fluid in the container and faces the heating element. The cooling member is configured in a laminated structure including a porous body provided on the heating element side and a working fluid introduction body provided on the working fluid side. The porous body includes a working fluid supply unit that supplies the working fluid to the contact portion with the heating element by capillary action, and a steam discharge unit that discharges the steam generated at the contact portion to the working fluid introduction body side. The working fluid introduction body is a cooler comprising a working fluid introduction section that guides the working fluid to the porous body.

In the cooler according to the embodiment of the present invention, the working fluid introduction body has a plurality of holes penetrating in the height direction, and the plurality of holes constitute the working fluid introduction section.

In a cooler according to another embodiment of the present invention, the plurality of holes constituting the working fluid introduction part of the working fluid introduction body have a circular or polygonal cross section.

In a cooler according to still another embodiment of the present invention, a gap region is provided between the working fluid introduction body and the porous body.

In a cooler according to still another embodiment of the present invention, the porous body is composed of an aggregate of porous particles.

In a cooler according to still another embodiment of the present invention, the porous body is composed of a porous layer.

In the cooler according to still another embodiment of the present invention, the porous body includes a first porous body provided on the heating element side and a second porous body provided on the working fluid introduction body side. The first porous body includes a first working fluid supply unit that supplies the working fluid to a contact portion with the heating element by capillary action, and the contact portion. A first vapor discharge section that discharges the generated vapor to the second porous body side, and the second porous body supplies the working fluid introduced by the working fluid introduction body to the first porous body. A second working fluid supply section for supplying the material, and a second steam discharge section for discharging the steam discharged from the first porous body to the working fluid introduction body side, the first porous It is formed of a porous body having a larger permeability of the working fluid than the solid body.

In the cooler according to still another embodiment of the present invention, the second porous body has a pore radius larger than that of the first porous body and / or has a porosity. By making it larger than the porosity of the first porous body, the permeability of the working fluid is made larger than that of the first porous body.

In the cooler according to still another embodiment of the present invention, either one of the first porous body and the second porous body is composed of an aggregate of porous particles, and the other is porous. It is composed of a quality layer.

In the cooler according to still another embodiment of the present invention, the first porous body is composed of an aggregate of porous nanoparticles, and the second porous body has a mesh structure. Consists of layers.

In the cooler according to still another embodiment of the present invention, the first porous body is formed of a porous layer, and the first vapor discharge portion is a hole penetrating the porous layer. is there.

In a cooler according to still another embodiment of the present invention, the working fluid introduction body is made of metal.

In a cooler according to still another embodiment of the present invention, an end portion of the working fluid introduction body formed of the metal is fixed to the heating element by welding.

In a cooler according to still another embodiment of the present invention, a radiating fin is welded to the heating element, and the working fluid introduction body is fixed to the radiating fin by welding.

Another aspect of the present invention is a cooling device including the cooler according to the present invention and a condenser that is connected to a container of the cooler and liquefies the evaporated working fluid.

According to another aspect of the present invention, there is provided a cooling method using a boiling system in which the heating element is cooled by at least partially immersing the heating element in a working fluid of a container containing the working fluid. A heating element in which a cooling member configured in a laminated structure including a porous body provided on the heating element side and a working fluid introduction body provided on the working fluid side is mounted on the surface of the portion immersed in The porous body has a working fluid supply unit that supplies the working fluid to a contact portion with the heating element by capillary action, and discharges steam generated at the contact portion to the working fluid introduction body side. And the working fluid introduction body includes a working fluid introduction section that guides the working fluid to the porous body.

In the heating element cooling method according to an embodiment of the present invention, the porous body includes a first porous body provided on the heating element side and a second porous body provided on the working fluid introduction body side. The first porous body includes a first working fluid supply unit that supplies the working fluid to a contact portion with the heating element by capillary action, and the contact portion. A first vapor discharge section that discharges the generated vapor to the second porous body side, and the second porous body supplies the working fluid introduced by the working fluid introduction body to the first porous body. A second working fluid supply section for supplying the material, and a second steam discharge section for discharging the steam discharged from the first porous body to the working fluid introduction body side, the first porous It is formed of a porous body having a larger permeability of the working fluid than the solid body.

In the heating element cooling method according to another embodiment of the present invention, nanoparticles are dispersed in the working fluid, and a mesh structure is formed on the surface of the portion immersed in the working liquid of the heating element. The second porous body composed of the porous layer and the working fluid introduction body are provided in this order, and the heat transfer from the heating element in which the nanoparticles in the working fluid are boiled by the heat from the heating element. The heating element is formed by forming the first porous body between the heating element and the second porous body by forming an aggregate of porous nanoparticles by depositing on the hot surface. The cooling member is mounted on the surface of the portion immersed in the working liquid.

The cooler of the present invention, the cooling device using the same, and the heating element cooling method have at least the following effects:
(1) A critical heat flux of about 2000 kW / m ² necessary to prevent melt-through at the bottom of the reactor pressure vessel, and more than about 2500 kW / m ² can be realized.
(2) When steam is generated in the working fluid supply section and the contact section of the porous body, liquid is forcibly supplied to the contact section by capillary action. Therefore, when using the pool boiling cooling system, working fluid such as water is used. The container (water tank) to be accommodated does not need to be provided with a water flow path, a pump or the like, can use a simple water reservoir, can have a simple structure, and installation cost and running cost are low.
(3) The thickness of the porous body provided at the contact portion with the heating element is preferably thin from the viewpoint of the capillary limit mechanism, but if it is too thin, the porous body is porous while the coalescing bubbles stay on the upper part of the porous body. Liquid drainage easily occurs inside the body, and the critical heat flux is reduced. Therefore, in the present invention, a working fluid introduction body including a working fluid introduction portion that guides the working fluid to the porous body is provided on the porous body provided on the contact portion with the heating element (on the working fluid side). According to such a configuration, the working fluid introduction body capable of supplying a sufficient amount of working fluid toward the porous body and holding the liquid between the porous body and the vapor mass above the porous body. Therefore, even if the thickness of the porous body is reduced, the occurrence of liquid withering is suppressed, and the critical heat flux can be prevented from being reduced.

It is a schematic diagram of the pressure vessel of a light water reactor (an example is a boiling water reactor). It is a schematic diagram of the cooler by the conventional pool boiling system. It is a figure for demonstrating the limit heat flux of the cooler by the conventional pool boiling system. It is a schematic diagram of the cooler by the pool boiling system which concerns on Embodiment 1. FIG. It is sectional drawing in the state which provided the cooling member which concerns on Embodiment 1 in the contact part. It is a top view of a porous body. (A) is an appearance photograph of a working fluid introduction body having a plurality of through-holes having a cross section formed in a regular hexagon, and (B) is a working fluid introduction body having a plurality of through-holes having a cross section formed in a perfect circle. (C) is an appearance photograph of a working fluid introduction body having a plurality of through-holes whose cross section is formed in a regular square shape, and (D) is a through-hole whose cross section is formed in a regular triangle shape. It is an external appearance photograph of the working fluid introduction body which has multiple. It is a schematic diagram of the cooler by the pool boiling system which concerns on Embodiment 2. FIG. It is sectional drawing in the state which provided the cooling member which concerns on Embodiment 2 in the contact part. (A) is a top view of a 1st porous body, (B) is a top view of a 2nd porous body. It is a schematic diagram of the cooler of the reactor pressure vessel bottom part of the light water reactor which concerns on Embodiment 3. FIG. It is the schematic diagram of embodiment by which the working fluid introduction body was fixed to the reactor pressure vessel bottom part which is a heat generating body by the end part by welding. (A) is a schematic diagram of a form in which each of the first porous body and the second porous body is composed of an aggregate of porous particles, and (B) is a diagram illustrating the first porous body and the second porous body. 2 is a schematic diagram of a form in which each of the two porous bodies is composed of a porous layer, and (C) is a set of porous particles in which one of the first porous body and the second porous body is formed. It is a schematic diagram of the form comprised by the body and the other is comprised by the porous layer. It is a cooling device concerning Embodiment 4. It is a schematic diagram of the deformation | transformation form of the cooling device which concerns on Embodiment 4. FIG. (A) is a top view of the 2nd porous body comprised by the porous layer of the mesh structure which has many rectangular holes, (B) is sectional drawing in the state which provided the cooling member in the contact part. It is. (A) is a schematic schematic diagram of the experimental apparatus used in the test example, and (B) is an example of the structure of the sample provided on the heat transfer surface on the copper cylinder of the experimental apparatus. It is a graph which shows the boiling curve obtained by the test a. It is a graph which shows the result of having arranged the data shown in FIG. 18 about the form (The shape of a hole: Cell geometry) of the working fluid introduction body. It is a graph which shows the boiling curve obtained by the test b. 21 is a graph showing a result of arranging the data shown in FIG. 20 with respect to the height of the structure of the working fluid introduction body (denoted as structure height). It is a graph which shows the boiling curve obtained by the test c. FIG. 23 is a graph showing the results of organizing the data shown in FIG. 22 with respect to the thickness of the wall portion that partitions each hole of the structure of the working fluid introduction body (expressed as cell size). It is a graph which shows the boiling curve obtained by the test d. 6 is a graph showing each critical heat flux obtained in Test Example 2.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 4 shows a cooler using a pool boiling method according to the first embodiment. The cooler includes a container for storing the working fluid, and a cooling member provided in the container so as to be in contact with the working fluid and to be in contact with the heating element. The cooling member has a laminated structure including a porous body provided on the heating element side and a working fluid introduction body provided on the working fluid side.

FIG. 5 is a cross-sectional view in a state where the cooling member according to the present embodiment is provided in the contact portion. FIG. 6 is a plan view of the porous body. The porous body includes a working fluid supply unit and a vapor discharge unit. A working fluid supply part supplies a working fluid to a contact part with a heat generating body by a capillary phenomenon. The steam discharge part discharges the steam generated by the heat from the heating element to the working fluid introduction body side from the contact part. In this embodiment, the porous body is composed of a porous layer, and has, for example, a mesh structure having a large number of rectangular holes, and a lattice-like porous layer portion around the rectangular holes is a capillary tube. It functions as a working fluid supply unit that supplies a working fluid to the contact unit due to the phenomenon, and a rectangular hole functions as a steam discharge unit that discharges steam generated at the contact unit to the working fluid introduction body side. As described above with reference to FIG. 3, the supply of the working fluid and the discharge of the steam are performed using separate paths in this manner, so that the steam covers the contact portion and the limit heat flux is limited. Can be suppressed. The working fluid introduction body includes a working fluid introduction section that guides the working fluid to the porous body, and the working fluid introduction section has a function of supplying the working fluid to the porous body and a function of holding the working fluid. Also, while the coalesced bubbles stay on the upper part of the working fluid introduction body, it functions so that the working fluid is quickly supplied to the porous body.

The working fluid can be a liquid having a surface tension such as water, a low-temperature fluid, a refrigerant, an organic solvent, or the like.

The pore radius of the porous body may be a radius of a hole originally provided in each porous body, or may be a radius of a hole formed in each porous body. Here, the shape of the pores of the porous body can be various shapes such as a polygonal shape, a circular shape, and an elliptical shape. The radius of the circumscribed circle at.

As the shape of the porous body, since the contact area of the porous body with the contact portion is large, the size of the hole for releasing the vapor generated at the contact portion into water is preferably small. For example, the pore radius is 100 to 2000 μm. It can be. In addition, since the pressure loss when passing through the porous bottom can be reduced, the gap between the holes for releasing the steam generated at the contact portion into the water is preferably small, and can be, for example, 100 to 1000 μm. .

The porous material constituting the working fluid supply unit in the porous material may be ceramics such as cordierite or sintered metal, for example. In particular, it is desirable to be composed of a porous body with good wettability such as oxide or a porous body that has been processed to improve wettability such as plasma irradiation.

When the liquid evaporates in the working fluid supply section, the porous body supplies the working fluid to the contact section by capillary action, but considering the limit mechanism of liquid supply by capillary force, the length of the capillary (ie As the thickness of the porous body is smaller, the limit, that is, the “limit heat flux” can be increased. On the other hand, FIG. 3 shows a state in which the vapor mass is formed on the contact portion under the high heat flux condition, but the volume of the vapor mass increases with time and eventually cuts off from the contact portion. If the vapor mass and the vicinity of the contact portion are described in more detail, a liquid film having a finite thickness (generally called a macro liquid film) exists between the vapor mass and the contact portion (that is, the bottom of the vapor mass). . Under such a high heat flux condition, burnout occurs when the macro liquid film at the bottom of the vapor mass is exhausted and exhausted while the vapor mass remains on the macro liquid film. The heat flux at this time is called “limit heat flux”. As described above, the thickness of the porous body is preferably thinner from the limit mechanism of liquid supply by capillary force (capillary limit mechanism). However, if the thickness is too thin and the same as the thickness of the macro liquid film, the first porous body Liquid drainage tends to occur near the contact portion, and the critical heat flux becomes small.

As described above, the thickness of the porous body provided in the contact portion with the heating element is preferably thin from the viewpoint of the capillary limit mechanism, but if it is thinner than the macro liquid film thickness, the liquid body is liable to wither inside the porous body. There is a problem that the critical heat flux becomes small. Therefore, in the present invention, a working fluid introduction body including a working fluid introduction section that guides the working fluid to the porous body is provided on the porous body provided on the contact portion with the heating element (on the working fluid side). . According to such a configuration, the working fluid is introduced between the porous body and the vapor mass above the porous body so as to supply the working fluid to the porous body and hold the working fluid above the porous body. Since the body exists, even if the thickness of the porous body is reduced, the occurrence of liquid withering is suppressed, and the critical heat flux can be prevented from being reduced. Further, since the larger the amount of liquid supplied to the working fluid introduction body, the better. Therefore, it is preferable to increase the thickness of the working fluid introduction body. Specifically, for example, when the thickness of the porous body is reduced to about 100 μm, the thickness of the working fluid introduction body is preferably about 1 mm or more.

In addition, although the porous body was circular in FIG. 5 and the vapor | steam discharge part showed the form of a grid | lattice form, it does not intend to limit to such a form. The steam discharge part may be formed in a honeycomb shape, for example. Further, in FIG. 5, the working fluid supply unit and the vapor discharge unit are illustrated so as to be orthogonal to the lower contact unit and the upper working fluid introduction body side, but the working fluid supply unit and the vapor discharge unit are in contact with the contact unit. As long as the path between the surface and the surface in contact with the working fluid introduction body is respectively provided, the path may be configured to be, for example, a curved path or a bent path without being orthogonal. Further, in the present embodiment, as described above, the rectangular holes of each porous body function as a vapor discharge part, but the shape of the holes is not particularly limited, and other polygonal shapes, circular shapes, oval shapes It may be a shape or the like. Further, the holes may be holes originally provided in each porous body, or may be holes formed in each porous body.

Further, the form of the porous body is not particularly limited, and for example, the porous body may be composed of an aggregate of porous particles. The porous body may be composed of a porous layer.

The working fluid introduction body may have a plurality of holes penetrating in the height direction, and the plurality of holes may constitute the working fluid introduction section. The plurality of holes constituting the working fluid introduction part of the working fluid introduction body may have a circular or polygonal cross section. An example of the working fluid introduction body having such a configuration will be given. FIG. 7 is external appearance photographs of various types of working fluid introduction bodies. FIG. 7A is an external view photograph of a working fluid introduction body having a plurality of through holes each having a regular hexagonal cross section. FIG. 7B is an external view photograph of the working fluid introduction body having a plurality of through-holes whose cross section is formed into a perfect circle. FIG. 7C is an external view photograph of a working fluid introduction body having a plurality of through holes each having a cross section formed in a regular square shape. FIG. 7D is an external view photograph of a working fluid introduction body having a plurality of through holes each having a cross section formed in a regular triangle shape. The cross-sectional shapes of the plurality of through holes of the working fluid introduction body are not limited to these, and may be formed in an elliptical shape, a pentagonal shape, a heptagonal shape, a polygonal shape having more than that, or the like.

The material constituting the working fluid introduction body may be a porous material or a non-porous material. As a material constituting the working fluid introduction body, it can be formed using a metal such as stainless steel or Teflon (registered trademark), a resin, or the like. In particular, by forming the working fluid introduction body with metal, the wettability of the working fluid introduction body is improved and the hydrophilicity is improved, so that it is possible to take in more working fluid and supply it to the heat transfer surface. Become.

The working fluid introduction body can supply the working fluid to the upper part of the porous body by appropriately setting the size (hydraulic diameter) of the through hole. Here, hydraulic diameter: De is represented by De = 4 × (through hole cross-sectional area / total perimeter of through-hole cross section). The appropriate pore size (hydraulic diameter) is specifically half of the Taylor instability wavelength, ie, (2π (σ / g (ρL−ρG)) ^0.5 ) / 2 [where σ is the surface T is the tension, g is the acceleration of gravity, ρ is the working fluid density, L is the liquid phase, and G is the gas phase. ]. Rather than placing the working fluid introduction body alone on the heat transfer surface, the limiting heat flux of the cooler is further improved by providing the porous body between the heat transfer surface as in the present invention. Further, the size of the hole (hydraulic diameter) in the through hole of the working fluid introduction body is set to 5 to 40 times the size of the hole of the porous body provided on the heating element side, so that the steam The discharge efficiency is improved and the cooling effect is improved.

It is preferable that a gap region is provided between the working fluid introduction body of the cooling member and the porous body. According to such a configuration, when the vapor bubbles are released, the portion becomes negative pressure, so that an effect that the liquid is supplied from the adjacent flow path can be obtained. The gap region may be provided continuously with the working fluid introduction body and the porous body completely separated from each other, or may be provided discontinuously with partial separation. The configuration of the gap region is not particularly limited, but when a continuous gap region is provided by being completely separated, the working fluid introduction body is fixed in a state of being separated from the porous body by a predetermined means such as a wire. It is good also as composition to do. Further, when the working fluid introduction body is partially separated from the porous body and the gap region is provided discontinuously, a partial defect portion is formed at the end of the working fluid introduction body on the side in contact with the porous body. It is good also as a structure which forms. Further, the height of the gap region is preferably 0.1 mm to 1 mm.

Furthermore, it is preferable that a gap region is formed at the contact portion between the porous body of the cooling member and the heating element. The vapor generated at the bottom surface of the working fluid supply unit of the porous body travels along the bottom surface of the working fluid supply unit, and then exits to the vapor discharge unit and is discharged upward from the vapor discharge unit. Here, when a gap region is formed at the contact portion between the porous body of the cooling member and the heating element, the gap region becomes a passage for the vapor generated at the bottom surface of the porous body, and the discharge of the vapor is promoted. The critical heat flux is improved. The gap area may be processed to be rough on the surface of the contact part, but since the gap area necessary for the discharge of the vapor is very small, simply contacting the porous body with the contact part from the beginning. A sufficient gap region is formed by the roughness of the surface of the contact portion. In addition, since the gap | emission area | region disappears, the vapor | steam discharge | emission property falls, but the porous body may be fixed to the contact part with the adhesive agent.

Further, as another aspect of the present invention, the entire heating element can be immersed in the working fluid, or a part of the heating element can be partially immersed from the liquid level of the working fluid for cooling. In this case, the heating element takes various forms depending on cases such as a floating state, a state where it is placed on the bottom surface of the container, and the important point is that the porous body and the working fluid introduction body are placed in the portion immersed in the working fluid. By attaching a cooling member having a laminated structure including the above, cooling can be performed in the same manner as in the above example.

According to the present invention, when steam is generated in the working fluid supply section and the contact section of the porous body, the liquid is forcibly supplied to the contact section by capillary action, so that the container (water tank) for storing the working fluid such as water In the case of a pool boiling cooling system, there is no need to provide a water flow path or the like, a simple water reservoir can be used, and a pump is not required, so that the structure can be simplified, installation cost and running Cost is low. In the present invention, a working fluid introduction body including a working fluid introduction section that guides the working fluid to the porous body is provided on the porous body provided on the contact portion with the heating element (on the working fluid side). With such a configuration, there is a working fluid introduction body that supplies a working fluid to the porous body and holds the working fluid between the porous body and the vapor mass above the porous body. Even if the thickness of the porous body is reduced, the occurrence of liquid withering is suppressed, and the critical heat flux can be prevented from becoming smaller. The installation cost and running cost are higher than those of the pool boiling cooling method. However, in the case of forced flow boiling cooling in which a flow path is provided and the working fluid is circulated by a pump, the critical heat flux is reduced by the same method. Can be prevented.

(Embodiment 2)
FIG. 8 shows a cooler using a pool boiling method according to the second embodiment. The cooler includes a container for storing the working fluid, and a cooling member provided in the container so as to be in contact with the working fluid and to be in contact with the heating element. The cooling member is configured in a laminated structure including first and second porous bodies provided on the heating element side and a working fluid introduction body provided on the working fluid side.

FIG. 9 is a cross-sectional view in a state where the cooling member according to the present embodiment is provided in the contact portion. FIG. 10 is a plan view of the first and second porous bodies. As shown in FIG. 10A, the first porous body includes a first working fluid supply unit and a first vapor discharge unit. The first working fluid supply unit supplies the working fluid to the contact portion with the heating element by capillary action. The first steam discharge unit discharges the steam generated by the heat from the heating element from the contact portion to the second porous body side. In the present embodiment, the first porous body is composed of a porous layer, and has, for example, a mesh structure having a large number of rectangular holes, and a lattice-like porous layer around the rectangular holes. The first vapor discharge in which the portion functions as a first working fluid supply unit that supplies the working fluid to the contact portion by capillary action, and the rectangular hole discharges the steam generated at the contact portion to the second porous body side It functions as a part. As described above with reference to FIG. 3, the supply of the working fluid and the discharge of the steam are performed using separate paths in this manner, so that the steam covers the contact portion and the limit heat flux is limited. Can be suppressed. Further, as shown in FIG. 10B, the second porous body is composed of a porous layer as in the case of the first porous body, for example, a mesh structure having a number of rectangular holes. The lattice-shaped porous layer portion around the rectangular hole functions as a second working fluid supply unit that supplies the working fluid to the first porous body, and the rectangular hole is the first hole. It functions as a second steam discharge section for discharging the steam discharged from the porous body to the working fluid introduction body side. The second porous body has a larger working fluid permeability than the first porous body, has a function of holding the working fluid, and coalesced bubbles stay in the upper portion of the second porous body. In the meantime, it functions so that the working fluid is quickly supplied to the first porous body.

The second porous body operates more than the permeability of the first porous body by making the pore radius of the porous body larger than the pore radius of the first porous body to facilitate the passage of the working fluid. The fluid permeability can be increased. Here, the pore radius of the porous body may be a radius of a hole originally provided in each porous body, or may be a radius of a hole formed in each porous body. Here, the shape of the pores of the porous body can be various shapes such as a polygonal shape, a circular shape, and an elliptical shape. The radius of the circumscribed circle at. Furthermore, the second porous body has a porosity of the porous body larger than that of the first porous body to facilitate the passage of the working fluid, so that the permeability of the first porous body is higher than that of the first porous body. The permeability of the working fluid can be increased. The porosity of the porous body can be increased, for example, by adjusting the particle size / amount of the binder to be mixed with the metal powder in the manufacturing process of the porous body.

As the shape of the first porous body, since the contact area of the porous body with the contact portion is large, the size of the hole for releasing the steam generated at the contact portion into water is preferably small. The thickness can be 100 to 2000 μm. In addition, since the pressure loss when passing through the porous bottom can be reduced, the gap between the holes for releasing the steam generated at the contact portion into the water is preferably small, and can be, for example, 100 to 1000 μm. .

The porous material constituting the first working fluid supply unit in the first porous body may be ceramics such as cordierite or a sintered metal, for example. In particular, it is desirable to be composed of a porous body with good wettability such as oxide or a porous body that has been processed to improve wettability such as plasma irradiation.

The first porous body supplies the working fluid to the contact portion by capillary action when the liquid evaporates in the first working fluid supply portion, but considering the limit mechanism of liquid supply by capillary force, As the capillary length (ie, the thickness of the first porous body) is thinner, the limit, that is, the “critical heat flux” can be increased. On the other hand, FIG. 3 shows a state in which the vapor mass is formed on the contact portion under the high heat flux condition, but the volume of the vapor mass increases with time and eventually cuts off from the contact portion. If the vapor mass and the vicinity of the contact portion are described in more detail, a liquid film having a finite thickness (generally called a macro liquid film) exists between the vapor mass and the contact portion (that is, the bottom of the vapor mass). . Under such a high heat flux condition, burnout occurs when the macro liquid film at the bottom of the vapor mass is exhausted and exhausted while the vapor mass remains on the macro liquid film. The heat flux at this time is called “limit heat flux”. As described above, the thickness of the first porous body is preferably thinner from the limit mechanism of liquid supply by capillary force (capillary limit mechanism), but if the thickness is too thin and is approximately the same as the thickness of the macro liquid film, Liquid withering tends to occur near the contact portion of the porous body, and the critical heat flux becomes small.

As described above, the thickness of the porous body provided in the contact portion with the heating element is preferably thin from the viewpoint of the capillary limit mechanism, but if it is thinner than the macro liquid film thickness, the liquid body is liable to wither inside the porous body. There is a problem that the critical heat flux becomes small. Therefore, in the present invention, the porous body provided at the contact portion with the heating element is the first porous body, and the permeability of the working fluid is higher than that of the first porous body (on the working fluid side). A large second porous body is provided. According to such a configuration, the second porous body that supplies the working fluid to the first porous body in an abundant manner between the first porous body and the vapor mass above the first porous body. Therefore, even if the thickness of the first porous body is reduced, the occurrence of liquid withering is suppressed, and the critical heat flux can be prevented from being reduced. Moreover, since it is so preferable that there are many liquid supply amounts of a 2nd porous body, it is preferable to also enlarge the thickness of a 2nd porous body. Specifically, for example, when the thickness of the first porous body is reduced to about 100 μm, the thickness of the second porous body is preferably about 1 to 2 mm or more.

The second porous body may be formed of ceramics such as cordierite, but is preferably formed of metal from the viewpoint of workability and strength. In particular, it is desirable to be composed of a porous body with good wettability such as oxide or a porous body that has been processed to improve wettability such as plasma irradiation.

FIG. 10 shows a form in which the first porous body and the second porous body are both circular, and the first and second vapor discharge portions are both in a lattice shape. There is no intention to limit to such a form. The first and second vapor discharge portions may be formed in a honeycomb shape, for example. FIG. 10 shows the first and second working fluid supply sections and the steam discharge section so as to be orthogonal to the lower contact section and the upper working fluid introduction body side. If a supply part and a vapor | steam discharge part respectively provide the path | route between the surface which contact | connects a contact part, and the surface which contact | connects a working fluid introduction body, it will become a curved path | route or a bent path | route, for example, without orthogonally crossing It may be configured as follows. Further, in the present embodiment, as described above, the rectangular holes of each porous body function as a vapor discharge part, but the shape of the holes is not particularly limited, and other polygonal shapes, circular shapes, oval shapes It may be a shape or the like. Further, the holes may be holes originally provided in each porous body, or may be holes formed in each porous body.

In addition, the form of the first porous body and the second porous body is not particularly limited. For example, the first porous body and the second porous body are both aggregates of porous particles. It may be configured. Moreover, both the 1st porous body and the 2nd porous body may be comprised by the porous layer. Furthermore, one of the first porous body and the second porous body may be composed of an aggregate of porous particles, and the other may be composed of a porous layer. In the case where the first porous body and the second porous body are composed of an aggregate of porous particles, for example, a gap between a plurality of porous particles has a function as a vapor discharge portion, and the gap It is possible to adopt a configuration in which the members around are functioning as a working fluid supply unit.

Further, the porous body of the cooling member is not limited to the one constituted by the first porous body and the second porous body, and the third porous body is further provided on the working fluid side of the second porous body. A porous body may be provided to form a total of three layers. In this case, the third porous body includes a working fluid supply unit that supplies the working fluid to the second porous body, and a steam discharge that discharges the steam discharged from the second porous body to the working fluid introduction body side. Department. Similarly, the porous body may be configured to have a total of four or more layers by laminating a plurality of porous bodies on the working fluid side of the second porous body.

(Embodiment 3)
In FIG. 11, the schematic diagram of the cooler of the reactor pressure vessel bottom part of the light water reactor which concerns on Embodiment 3 is shown. A support ring is attached so as to surround the reactor in the circumferential direction from the side of the reactor, and a honeycomb mounting net (metal mesh) supported by the support ring is attached. The honeycomb mounting net may not be made of metal but may be formed of a heat resistant resin. As a method of attaching the cooler at the bottom of the reactor pressure vessel, first, a cooling member having a laminated structure of a honeycomb-like porous body and a working fluid introduction body is provided so as to cover the bottom of the reactor pressure vessel and temporarily fixed. . Next, after the honeycomb mounting net is lowered from the support ring to cover the bottom of the reactor pressure vessel, the honeycomb mounting net is pulled near the support ring to bring the honeycomb mounting net into contact with the bottom of the reactor pressure vessel. By doing so, a cooler can be easily attached to the bottom of the reactor pressure vessel. The cooling member is structured to be held from below by the honeycomb mounting net. The honeycomb mounting net may not be a mesh, and may be formed using a plurality of tapes because the construction is simpler. Moreover, a part including the deepest part of the reactor pressure vessel bottom is immersed in a vessel containing water. The porous body of the cooling member and the working fluid introduction body have the same structure as that described in the first embodiment, realize a good critical heat flux, and prevent melt-through at the bottom of the reactor pressure vessel. Therefore, it is possible to realize a critical heat flux of about 2000 kW / m ² which is necessary for this purpose, and about 2500 kW / m ² or more beyond that. Thus, the cooler according to the present invention is particularly suitable for cooling the bottom of the reactor pressure vessel in the event of a reactor accident. In FIG. 11, the cooling member covers a part of the bottom of the reactor pressure vessel. However, the cooling member may be provided so as to cover all of the portion immersed in the vessel containing water at the bottom of the reactor pressure vessel. Good.

The cooling member provided with the honeycomb-shaped porous body and the working fluid introduction body so as to cover the bottom of the reactor pressure vessel according to the third embodiment may be supported without using the honeycomb mounting net. For example, as shown in FIG. 12, the porous body and the working fluid introduction body are supported by forming the working fluid introduction body from metal and fixing the end of the working fluid introduction body to the bottom of the reactor pressure vessel, which is a heating element. May be. Welding is preferably spot welding because it is easy to work and provides sufficient support. Moreover, the radiation fin is welded to the heat generating body, and the working fluid introduction body may be fixed to the radiation fin by welding. According to such a configuration, the heat from the heat generating element is released from the heat radiation fin, so that the heat generating element can be cooled more favorably.

Further, when the porous body is composed of the first and second porous bodies, the first porous body and the second porous body are both porous as shown in FIG. You may be comprised with the aggregate | assembly of particle | grains. Moreover, as shown to FIG. 13 (B), both the 1st porous body and the 2nd porous body may be comprised with the porous layer. Furthermore, as shown in FIG. 13C, one of the first porous body and the second porous body is composed of an aggregate of porous particles, and the other is composed of a porous layer. May be. In FIG. 13, when the porous body is composed of an aggregate of porous particles, the aggregate of porous particles is wrapped with a fine mesh material to such an extent that the particles cannot pass through. Although it does not specifically limit as the said mesh material, For example, it can form with the honeycomb mounting | wearing net | network made from metal or a heat resistant resin. In FIG. 13, the working fluid introduction body laminated on the second porous body is not shown.

(Embodiment 4)
FIG. 14 shows a cooling device according to the fourth embodiment. The cooling device includes the cooler according to the first embodiment and a capacitor connected to the container. In the condenser, the evaporated working fluid is liquefied and returned to the container. The cooling device does not require an external power source such as a pump, and is excellent in compactness and energy saving as the entire device. FIG. 15 shows a modification of the cooling device according to the fourth embodiment. 14 and 15 can be used together with the cooler of the third embodiment.

(Embodiment 5)
As a fifth embodiment, the cooling device of the present invention gradually increases the pore diameter from the porous body having a small pore diameter from the first porous body to the second porous body constituting the porous body of the cooling member. You may comprise so that a porous body may be laminated | stacked in steps. Further, at this time, the porous body on the side in direct contact with the bulk liquid is preferably formed so that the pore diameter is different from the diameter of fine particles such as dust existing in a large amount of working fluid such as water. preferable. For example, it is preferable that the porous body on the side in direct contact with the bulk liquid has a pore diameter sufficiently larger or smaller than the diameter of the fine particles. According to such a configuration, it is possible to expect the effect of suppressing the clogging phenomenon that occurs when the fine particles existing in the working fluid enter deep inside the porous body, and the liquid supply effect to the heat transfer surface by the porous body Can be maintained for a long time. In principle, for example, a porous body having a large pore diameter is gradually laminated from a porous body having a small pore diameter, and the outermost pore diameter of the porous body is set to be a working fluid. If the particle size of the dust inside is sufficiently larger or smaller than that, the dust particles that have flowed in do not immediately penetrate into the deep part of the porous body, but are formed immediately after entering the porous body. It accumulates from the vicinity of the entrance of the porous body due to the influence of starch and the like. Therefore, clogging starts from the outermost 300 μm pores of the porous body, and fine particles can be prevented from entering the deep part inside the porous body and forming clogging into the porous body. .

(Embodiment 6)
FIG. 16 shows a cooling device according to the sixth embodiment. As shown in FIG. 16, the first porous body may be composed of an aggregate of porous nanoparticles, and the second porous body may be composed of a porous layer having a mesh structure. FIG. 16A is a plan view of a second porous body composed of a mesh-structured porous layer having a large number of rectangular holes, and FIG. 16B is a cooling member provided at the contact portion. FIG. The first porous body is composed of an aggregate of nanoparticles having an average particle diameter of 10 to 50 nm. Examples of the nanoparticles that can be used include metals, alloys, oxides, nitrides, carbides, and carbon.

As a method for installing the cooling member according to the sixth embodiment, for example, an aqueous solution in which nanoparticles are diffused is provided by a predetermined means on the heat transfer surface where the first porous body is to be formed, and the state While heating, boil by heating on the heat transfer surface. In this way, the porous nanoparticles are deposited on the boiling heat transfer surface to form an aggregate, which becomes the first porous body. Next, a second porous body composed of a porous layer having a mesh structure and a working fluid introduction body are provided in this order on the aggregate of the porous nanoparticles. Thereby, the cooling composed of the first porous body composed of the aggregate of the porous nanoparticles, the second porous body composed of the porous layer having the mesh structure, and the working fluid introduction body. A member can be provided. In addition, as a method of providing the cooling member, a second porous body and a working fluid introduction body are provided on the surface of the heating element, and then, between the surface of the heating element and the second porous body. A first porous body may be provided. As such a configuration, for example, the second is configured by a porous layer having a mesh structure on the surface of a part immersed in the working liquid of the heating element in which nanoparticles are dispersed in the working fluid. The porous body and the working fluid introduction body are provided in this order, and the nanoparticles in the working fluid are deposited on the heat transfer surface of the heating body by the heat from the heating body, and the porous nanoparticles are aggregated. By forming the body, the first porous body is formed between the heating element and the second porous body, so that the cooling member is mounted on the surface of the portion immersed in the working liquid of the heating element. Specifically, for example, a honeycomb porous body (second porous body) and a working fluid introduction body are provided in advance in a pressure vessel of a nuclear reactor, and nanoparticles are supplied and dispersed in the working fluid when an accident occurs. . Subsequently, the working fluid containing the nanoparticles boiled on the working fluid side surface (heat transfer surface) of the pressure vessel, so that a set of porous nanoparticles is formed between the heat transfer surface and the second porous body. A first porous body composed of the body is formed.

In the sixth embodiment, the aggregate of nanoparticles constituting the first porous body has a large number of pores between or within the particles constituting the first working fluid supply section or the first vapor discharge section. ing. Also in this embodiment, the first porous body performs the supply of the working fluid and the discharge of the steam using separate paths, so that the steam covers the contact portion as described with reference to FIG. The occurrence of the problem that the critical heat flux is limited can be suppressed. Further, the second porous body functions as a second working fluid supply section in which the lattice-shaped porous layer portion around the rectangular holes supplies the working fluid to the first porous body. The holes function as a second vapor discharge unit that discharges the vapor discharged from the first porous body into the working fluid. The second porous body has a larger working fluid permeability than the first porous body, has a function of holding the working fluid, and coalesced bubbles stay in the upper portion of the second porous body. In the meantime, it functions so that the working fluid is quickly supplied to the first porous body. In Embodiment 6, since the first porous body is composed of an aggregate of porous nanoparticles, the heat transfer surface has good wettability, and the second porous body is composed of a porous layer having a mesh structure. By using this porous body, the supply performance of the working fluid to the heat transfer surface becomes better. Thereby, it becomes difficult to produce the dry area | region of a heat-transfer surface, and it can prevent that a limit heat flux becomes small.

The present invention can be applied to various electronic devices and other thermal devices having a high heat generation density in addition to cooling of the reactor pressure vessel. For example, divertor cooling in fusion reactors, high performance of capillary pump loops, semiconductor lasers, data center server cooling, CFC-cooled chopper control devices, power electronics, and the like are conceivable. Alternatively, it can be applied to a water-cooled jacket that improves the high-temperature work environment by reducing the heat dissipated from the side or bottom of a glass or aluminum melting furnace to the surrounding environment. Furthermore, the present invention can be applied to a water-cooled jacket installed on the side of the fire wall or the bottom of the fire wall to reduce damage by cooling the fire wall such as a large garbage incinerator from the outside.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

(Test Example 1)
FIG. 17 shows a schematic diagram of the experimental apparatus. FIG. 17A shows a schematic schematic diagram of the experimental apparatus, and FIG. 17B shows an example of the structure of the cooling member (sample) provided on the heat transfer surface on the copper cylinder of the experimental apparatus. The diameter of the contact portion in contact with the working fluid of the experimental apparatus was 50 mm. A copper cylinder embedded with a cartridge heater was used as a heating element. The amount of heating was controlled by controlling the voltage applied to the cartridge heater with a variable autotransformer. Extrapolation using the outputs from three φ0.5K type sheathed thermocouples installed on the center axis of copper cylinders of 10 mm, 15 mm and 20 mm respectively from the contact part, the superheat degree of the contact part, the indicated temperature difference and the set distance and The heat flux was calculated from the thermal conductivity by the Fourier equation. The container was a Pyrex (registered trademark) tube so that the state of internal boiling could be observed. The working liquid was distilled water at a depth of 170 mm and heated with a heater to maintain the saturation temperature. The generated steam was condensed by a condenser provided at the upper end of the Pyrex (registered trademark) tube and returned to the container.

A disk (trade name: MF-Millipore) having a mixture of cellulose acetate and cellulose nitrate was used as the porous body of the cooling member. The diameter of the porous disk was 50 mm, the diameter of the discharge port (round shape) of the steam discharge part was 1.9 mm, the hole radius was 0.8 μm, the porosity was 80%, and the plate thickness was 0.15 mm. As a working fluid introduction body of the cooling member, No. 1 to 12 stainless steel structures of various forms were prepared. In Table 1, h of the structure indicates the height, l indicates the length of the side of each hole (hexagon, triangle, or square) of the structure, D indicates the diameter of each hole of the structure, and δ _w represents the thickness of the wall portion that partitions each hole of the structure.

In the experiment, heating was performed while increasing the voltage of the cartridge heater in increments of 5 V under atmospheric pressure (0.1 MPa), and it was confirmed that the temperature was sufficiently steady, and the output voltage of the thermocouple was recorded. Here, whether or not the steady state was reached was determined by whether or not the temperature change for 20 minutes was 1K or less. This operation was repeated until the steady state could not be maintained.

(Test a) Relationship between the hole shape of the structure of the working fluid introduction body and the critical heat flux In order to examine the relationship between the hole shape of the structure of the working fluid introduction body and the critical heat flux, the porous body Above, no. The above experiment was conducted using one of the working fluid introduction bodies 1 to 4 as a cooling member. In addition, no. 0. FIG. 18 shows a boiling curve obtained in the experiment. The boiling curve represents the characteristics of boiling heat transfer, and the vertical axis represents the heat flux, and the horizontal axis represents the difference between the heating element temperature and the liquid saturation temperature, that is, the degree of superheat ΔTsat [K] at the contact portion. FIG. 19 shows the result of arranging the data shown in FIG. 18 with respect to the form of the working fluid introduction body (hole shape: expressed as Cell geometry). 18 to 19, it was found that the critical heat flux is higher in the case where the working fluid introduction body is provided on the cooling member regardless of the shape than in the case where nothing is provided.

(Test b) Relationship between the height of the structure of the working fluid introduction body and the critical heat flux In order to examine the relationship between the height of the structure of the working fluid introduction body and the critical heat flux, , No. The above experiment was conducted using any one of 3, 5 to 8 working fluid introduction bodies as a cooling member. FIG. 20 shows a boiling curve obtained in the experiment. FIG. 21 shows the result of arranging the data (Nos. 5 to 8) shown in FIG. 20 with respect to the height of the structure of the working fluid introduction body (denoted as structure height). 20 to 21, it was found that the critical heat flux varies depending on the height of the structure of the working fluid introduction body.

(Test c) Relationship between the thickness of the wall part partitioning each hole of the structure of the working fluid introduction body and the limit heat flux The thickness of the wall part partitioning each hole of the structure of the working fluid introduction body, and the limit heat flux In order to examine the relationship of The above experiment was carried out using any one of 3, 9 to 12 working fluid introduction bodies as a cooling member. FIG. 22 shows the boiling curve obtained in the experiment. FIG. 23 shows the result of arranging the data shown in FIG. 22 with respect to the thickness (indicated as cell size) of the wall portion partitioning each hole of the structure of the working fluid introduction body. From FIGS. 22 to 23, it was found that the critical heat flux varies depending on the thickness of the wall portion partitioning each hole of the structure of the working fluid introduction body.

(Test d) Influence on the critical heat flux when the working fluid introduction body is used In order to examine the influence on the critical heat flux when the working fluid introduction body is used, No. 2 is formed on the porous body. No. 3 working fluid introduction body as a cooling member, No. 3 The above experiment was carried out by preparing only 3 as a cooling member and preparing only the porous body as a cooling member. FIG. 24 shows the boiling curve obtained in the experiment. From FIG. 24, it was found that the critical heat flux is the largest when the working fluid introduction body is provided on the porous body as the cooling member.

(Test Example 2)
In order to examine the relationship between the layered structure of the cooling member and the critical heat flux, the following experiment was conducted. In the experiment, an experimental apparatus shown in FIG. Further, it provided the porous layer (NP) by coating the nanoparticles (TiO ₂₎ to the heat transfer surfaces on the copper cylinder of the experimental device. In addition, a stainless lattice structure (MS) having a square cell (vapor discharge part) with a side of 11.26 mm and a height of 25 mm was prepared as a working fluid introduction body. Further, a honeycomb porous body (HP) having a square cell (hole) with a side of 1.4 mm and a plate thickness of 1.0 mm, which is a disc of a mixture of cellulose acetate and cellulose nitrate, was prepared. .
Next, the heat flux was measured by the same method as in Test Example 1 except for the cooling member provided on the heat transfer surface. In the experiment, a cooling member is not provided on the heat transfer surface (BS), only a nanoparticle porous layer (NP) is provided on the heat transfer surface, and only a lattice structure (MS) is provided on the heat transfer surface. A honeycomb porous body (HP) provided on the heat transfer surface, a nanoparticle porous layer provided on the heat transfer surface, and a honeycomb porous body provided thereon (NP + HP), and The test was carried out for each of the samples (NP + HP + MS) in which a porous layer of nanoparticles was provided on the heat transfer surface, a honeycomb porous body was further provided thereon, and a lattice structure was further provided thereon. The experimental result of the obtained critical heat flux is shown in FIG.
According to FIG. 25, the limiting heat flux is the one in which a porous layer of nanoparticles is provided on the heat transfer surface, a honeycomb porous body is further provided thereon, and a lattice structure is further provided thereon (NP + HP + MS). Was found to be larger.

Claims

A cooler by a boiling system for cooling a heating element,
A container containing a working fluid;
A cooling member provided in the container so as to contact the working fluid and to face the heating element;
The cooling member is configured in a laminated structure including a porous body provided on the heating element side and a working fluid introduction body provided on the working fluid side,
The porous body includes a working fluid supply unit that supplies the working fluid to a contact portion with the heating element by a capillary phenomenon, and a steam discharge portion that discharges steam generated at the contact portion to the working fluid introduction body side. Prepared,
The said working fluid introduction body is a cooler provided with the working fluid introduction part which guides the said working fluid to the said porous body.
The cooler according to claim 1, wherein each of the working fluid introduction bodies has a plurality of holes penetrating in a height direction, and the plurality of holes constitute the working fluid introduction section.
The cooler according to claim 2, wherein the plurality of holes constituting the working fluid introduction portion of the working fluid introduction body have a circular or polygonal cross section.
The cooler according to any one of claims 1 to 3, wherein a gap region is provided between the working fluid introduction body and the porous body.
The cooler according to any one of claims 1 to 4, wherein the porous body is composed of an aggregate of porous particles.
The cooler according to any one of claims 1 to 4, wherein the porous body is composed of a porous layer.
The porous body is configured in a laminated structure including a first porous body provided on the heating element side and a second porous body provided on the working fluid introduction body side,
The first porous body includes a first working fluid supply section that supplies the working fluid to a contact section with the heating element by capillary action, and vapor generated at the contact section on the second porous body side. A first steam discharge section for discharging to
The second porous body is discharged from the first porous body and a second working fluid supply unit that supplies the working fluid introduced by the working fluid introduction body to the first porous body. And a second steam discharge section for discharging the steam to the working fluid introduction body side, and is formed of a porous body having a larger permeability of the working fluid than the first porous body. 5. The cooler according to any one of 4.
The second porous body has a pore radius larger than that of the first porous body and / or a porosity larger than that of the first porous body. The cooler according to claim 7, wherein a permeability of the working fluid is larger than that of the first porous body.
The one of the first porous body and the second porous body is composed of an aggregate of porous particles, and the other is composed of a porous layer. Cooler.
The cooler according to claim 9, wherein the first porous body is composed of an aggregate of porous nanoparticles, and the second porous body is composed of a porous layer having a mesh structure.
The cooler according to claim 9, wherein the first porous body is formed of a porous layer, and the first vapor discharge portion is a hole penetrating the porous layer.
The cooler according to any one of claims 1 to 11, wherein the working fluid introduction body is made of metal.
The cooler according to claim 12, wherein an end portion of the working fluid introduction body formed of the metal is fixed to the heating element by welding.
14. The cooler according to claim 13, wherein a radiating fin is welded to the heating element, and the working fluid introduction body is fixed to the radiating fin by welding.
The cooler according to any one of claims 1 to 14,
A cooling device comprising a condenser connected to the container of the cooler and liquefying the evaporated working fluid.
In the cooling method by the boiling method in which the heating element is cooled at least partially by immersing the heating element in the working fluid of the container containing the working fluid,
Cooling configured in a laminated structure including a porous body provided on the heating element side and a working fluid introduction body provided on the working fluid side on the surface of the part immersed in the working liquid of the heating element A method of cooling a heating element to which a member is attached,
The porous body includes a working fluid supply unit that supplies the working fluid to a contact portion with the heating element by a capillary phenomenon, and a steam discharge portion that discharges steam generated at the contact portion to the working fluid introduction body side. Prepared,
The method for cooling a heating element, wherein the working fluid introduction body includes a working fluid introduction section that guides the working fluid to the porous body.
The porous body is configured in a laminated structure including a first porous body provided on the heating element side and a second porous body provided on the working fluid introduction body side,
The first porous body includes a first working fluid supply section that supplies the working fluid to a contact section with the heating element by capillary action, and vapor generated at the contact section on the second porous body side. A first steam discharge section for discharging to
The second porous body is discharged from the first porous body and a second working fluid supply unit that supplies the working fluid introduced by the working fluid introduction body to the first porous body. And a second steam discharge section for discharging the steam to the working fluid introduction body side, and formed of a porous body having a higher permeability of the working fluid than the first porous body. The heating element cooling method described.
Nanoparticles are dispersed in the working fluid, and the second porous body composed of a porous layer having a mesh structure on the surface of the portion immersed in the working liquid of the heating element, and the The working fluid introduction body is provided in this order,
The heat from the heating element causes the nanoparticles in the working fluid to precipitate on the heat transfer surface of the heating element to form an aggregate of porous nanoparticles, thereby forming the first porous body into the heat generation The heating element cooling method according to claim 17, wherein the cooling member is attached to a surface of a portion of the heating element that is immersed in the working liquid by being formed between the body and the second porous body.