JP7590887B2 - Heat exchange member and heat exchanger - Google Patents

Description

The present invention relates to a heat exchange member and a heat exchanger.

In recent years, there has been a demand for improved fuel economy in automobiles. In particular, to prevent a deterioration in fuel economy when the engine is cold, such as when the engine is started, there is a demand for systems that can quickly warm the coolant, engine oil, automatic transmission fluid (ATF), etc., thereby reducing friction loss. There is also a demand for systems that can heat exhaust gas purification catalysts in order to quickly activate them.

An example of such a system is a heat exchanger. A heat exchanger is a device that exchanges heat between a first fluid and a second fluid by circulating a first fluid inside and a second fluid outside. In such a heat exchanger, heat can be effectively utilized by exchanging heat from a high-temperature fluid (such as exhaust gas) to a low-temperature fluid (such as cooling water).

As a heat exchanger for recovering heat from high-temperature gas such as exhaust gas from an automobile, a heat exchanger using a heat exchange member having a honeycomb structure has been proposed. Also, a heat exchanger using a heat exchange member having a hollow honeycomb structure having a hollow region that functions as a bypass path for exhaust gas has been proposed.
For example, Patent Document 1 proposes a heat exchanger comprising a hollow honeycomb structure having partition walls, inner and outer walls that penetrate from a first end face to a second end face to define cells that serve as flow paths for a first fluid, and a covering member that covers the outer wall of the honeycomb structure, in which cells are arranged radially in a cross section of the honeycomb structure perpendicular to the flow path direction of the first fluid, and the heat exchange member has inner and outer walls whose thicknesses are greater than the thickness of the partition walls, and a frame (outer cylinder) that forms a flow path for a second fluid between the heat exchange member and the covering member.

International Publication No. 2019/135312

In the heat exchanger described in Patent Document 1, the first fluid flowing through the cells on the inner circumferential wall side is far from the second fluid flowing around the outer periphery of the covering member, so heat recovery is not sufficient (i.e., the first fluid flows at a high temperature). On the other hand, the first fluid flowing through the cells on the outer circumferential wall side is close to the second fluid flowing around the outer periphery of the covering member, so heat recovery is easy to perform (i.e., the first fluid is easily cooled to a low temperature).
In addition, the first fluid flowing through the cell on the supply port side of the second fluid is easy to recover heat from because the temperature of the second fluid is low, whereas the first fluid flowing through the cell on the discharge port side of the second fluid is difficult to exchange heat sufficiently because the temperature of the second fluid is high.
Due to the above-mentioned factors, conventional heat exchange elements have a problem in that the heat recovery efficiency is not sufficiently improved.

The present invention has been made to solve the above problems, and aims to provide a heat exchange member and a heat exchanger that can improve heat recovery efficiency.

The above problems are solved by the present invention, which is specified as follows:

The present invention relates to a honeycomb structure having an outer peripheral wall and partition walls disposed inside the outer peripheral wall and defining a plurality of cells that serve as a flow path for a first fluid extending from a first end surface to a second end surface;
A covering member that covers an outer peripheral surface of the outer peripheral wall,
In a cross section of the honeycomb structure perpendicular to a flow path direction of the first fluid, the partition walls include one or more first partition walls extending in a radial direction and one or more second partition walls extending in a circumferential direction,
The first partition wall is a heat exchange member having one or more communication holes.

The present invention also relates to a heat exchange member,
and an outer cylinder disposed radially outwardly of the covering member at a distance therefrom so that a second fluid can flow around the outer periphery of the covering member.

The present invention provides a heat exchange member and a heat exchanger that can improve heat recovery efficiency.

1 is a cross-sectional view of a heat exchanger element according to an embodiment of the present invention, taken along a line parallel to the axial direction of a honeycomb structure. 2 is a cross-sectional view of the heat exchanger member shown in FIG. 1 taken along line a-a'. 4 is a partially enlarged cross-sectional view of a first partition wall, taken along a line parallel to a flow path direction of a first fluid and perpendicular to a thickness direction of the first partition wall. FIG. 4 is a partially enlarged cross-sectional view of the second partition wall, taken along a line parallel to the flow path direction of the first fluid and perpendicular to a thickness direction of the second partition wall. FIG. 4 is a partial enlarged cross-sectional view of a partition wall parallel to a flow path direction of a first fluid and a thickness direction of the partition wall. FIG. FIG. 2 is a cross-sectional view of a hollow honeycomb structure perpendicular to the flow path direction of a first fluid. FIG. 4 is a partially enlarged perspective view of a honeycomb segment in which communicating holes are formed by machining. 1 is a cross-sectional view of a honeycomb structure of a heat exchanger according to an embodiment of the present invention, taken along a line parallel to a flow path direction of a first fluid. A cross-sectional view of the heat exchanger shown in Figure 8 along line b-b'.

The following describes in detail the embodiments of the present invention with reference to the drawings. The present invention is not limited to the following embodiments, and it should be understood that modifications and improvements to the following embodiments, as appropriate, based on the ordinary knowledge of those skilled in the art, fall within the scope of the present invention, provided they do not deviate from the spirit of the present invention.

(1) Heat exchange member Fig. 1 is a cross-sectional view parallel to the axial direction of a honeycomb structure of a heat exchange member according to an embodiment of the present invention. Fig. 2 is a cross-sectional view of the heat exchange member shown in Fig. 1 taken along line aa', that is, a cross-sectional view perpendicular to the flow path direction (axial direction) of a first fluid of the honeycomb structure of the heat exchange member according to an embodiment of the present invention.
The heat exchange member 100 according to the embodiment of the present invention includes a honeycomb structure 10 having an outer peripheral wall 11, partition walls 12 disposed inside the outer peripheral wall 11 and partitioning a plurality of cells 15 that serve as a flow path for a first fluid extending from a first end face 13 to a second end face 14, and a covering member 20 that covers the outer peripheral surface of the outer peripheral wall 11. In the heat exchange member 100 having such a structure, heat exchange between the first fluid that can flow in the cells 15 and the second fluid that can flow around the outer periphery of the covering member 20 is performed through the outer peripheral wall 11 of the honeycomb structure 10 and the covering member 20. In FIG. 1, the first fluid can flow in either the left or right direction of the paper. The first fluid is not particularly limited, and various liquids or gases can be used. For example, when the heat exchange member 100 is used in a heat exchanger mounted on an automobile, the first fluid is preferably exhaust gas.

The partition walls 12 constituting the honeycomb structure 10 include one or more first partition walls 12a extending in the radial direction and one or more second partition walls 12b extending in the circumferential direction in a cross section of the honeycomb structure 10 perpendicular to the flow direction of the first fluid (i.e., the cross section shown in FIG. 2). In particular, by providing one or more first partition walls 12a extending in the radial direction, it is possible to facilitate the transfer of heat of the first fluid in the radial direction via the first partition walls 12a.

At least one of the first partition wall 12a and the second partition wall 12b has one or more communication holes 16. Note that, although Fig. 2 shows an example in which one or more communication holes 16 are provided in both the first partition wall 12a and the second partition wall 12b, it should be noted that one or more communication holes 16 may be provided in either one of the first partition wall 12a and the second partition wall 12b.
Here, Figure 3 shows a partially enlarged cross-sectional view of the first partition wall 12a parallel to the flow direction of the first fluid (axial direction of the honeycomb structure 10) and perpendicular to the thickness direction of the first partition wall 12a, and Figure 4 shows a partially enlarged cross-sectional view of the second partition wall 12b parallel to the flow direction of the first fluid and perpendicular to the thickness direction of the second partition wall 12b.
There is no particular limitation on the position at which the one or more communication holes 16 are formed in the first partition wall 12a. For example, the communication holes 16 provided in the first partition wall 12a may be configured to allow the first fluid to flow between the adjacent cells 15 separated by the first partition wall 12a.
Similarly, the position at which the one or more communication holes 16 are formed in the second partition wall 12b is not particularly limited. For example, the communication holes 16 provided in the second partition wall 12b may be configured to allow the first fluid to flow between the adjacent cells 15 separated by the second partition wall 12b.

When the first partition wall 12a is provided with the communication hole 16, the circumferential deviation of the temperature of the first fluid flowing through the cell 15 can be reduced, improving the heat recovery efficiency. Specifically, in a heat exchanger (described in detail below) including a heat exchange member 100 and an outer cylinder having a supply port and an outlet port for the second fluid, the temperature of the first fluid flowing through the cell on the supply port side of the second fluid is easy to decrease (easy to exchange heat) because the temperature of the second fluid is low, whereas the temperature of the first fluid flowing through the cell on the outlet side of the second fluid is difficult to decrease (difficult to exchange heat) because the temperature of the second fluid is high, resulting in the temperature of the first fluid flowing through the cell 15 varying in the circumferential direction. However, by providing the communication hole 16 in the first partition wall 12a, the temperature of the first fluid is less likely to be biased in the circumferential direction, making it possible to efficiently transfer the heat of the first fluid to the second fluid.

When the second partition wall 12b is provided with the communication holes 16, the temperature deviation in the radial direction (diameter direction) of the first fluid flowing through the cells 15 can be reduced, improving the heat recovery efficiency. Specifically, the first fluid flowing through the cells 15 on the center side is less likely to have a low temperature because it is far from the second fluid, whereas the first fluid flowing through the cells 15 on the outer peripheral wall 11 side is more likely to have a low temperature because it is close to the second fluid, resulting in the temperature of the first fluid flowing through the cells 15 being biased in the radial direction. However, by providing the communication holes 16 in the second partition wall 12b, the temperature of the first fluid is less likely to be biased in the radial direction, making it possible to efficiently transfer the heat of the first fluid to the second fluid.

The above-mentioned effect can be obtained by providing the communication holes 16 in either the first partition 12a or the second partition 12b, but from the viewpoint of further improving the heat recovery efficiency, it is preferable to provide them in both the first partition 12a and the second partition 12b.

The shape of the communication hole 16 is not particularly limited, and may be various shapes such as those shown in Figures 3 and 4. Among these, from the viewpoint of processability, the shape of the communication hole 16 is preferably a circle, an ellipse, or a polygon. Furthermore, when a plurality of communication holes 16 are provided, the shapes of the communication holes 16 may be the same or different, but from the viewpoint of processability, it is preferable that the shapes of the communication holes 16 are the same.
The shape of the communication hole 16 means the shape of the communication hole 16 in a cross section of the first partition wall 12a or the second partition wall 12b parallel to the flow path direction of the first fluid (the axial direction of the honeycomb structure 10).

The position of the second partition 12b in which the communication hole 16 is provided is not particularly limited, but in the cross section shown in FIG. 2, it is preferable that the communication hole 16 is provided in all of the two or more second partitions 12b located between adjacent first partitions 12a in the radial direction (i.e., the two or more second partitions 12b that respectively constitute the two or more cells 15 arranged in the radial direction via the second partitions 12b). With this configuration, it is possible to enhance the effect of reducing the radial (radial) bias in the temperature of the first fluid flowing through the cells 15, thereby further improving the heat recovery efficiency.

In addition, in the cross section shown in FIG. 2, it is preferable that communication holes 16 are provided in each circumferential region of one second partition 12b located between adjacent first partitions 12a (i.e., all regions of one second partition 12b that each constitute two or more cells 15 arranged in the circumferential direction via the first partition 12a). With this configuration, it is possible to reduce the circumferential bias of the temperature of the first fluid flowing through the cells 15, thereby further improving the heat recovery efficiency.

The position of the first partition 12a where the communication hole 16 is provided is not particularly limited. However, since the first partition 12a contributes to the thermal conduction in the radial direction as described above, providing communication holes 16 in all of the first partitions 12a may hinder the thermal conduction in the radial direction and reduce the heat recovery efficiency. Therefore, from the viewpoint of ensuring stable thermal conduction in the radial direction, it is preferable that a part of the first partition 12a has one or more communication holes 16. With this configuration, it is possible to improve the heat recovery efficiency while suppressing the inhibition of the thermal conduction in the radial direction.

As described above, in a heat exchanger including a heat exchange member 100 and an outer cylinder having a supply port and a discharge port for a second fluid, the temperature of the first fluid flowing through the cells on the supply port side of the second fluid is easy to drop (easy to exchange heat) because the temperature of the second fluid is low, whereas the temperature of the first fluid flowing through the cells on the discharge port side of the second fluid is difficult to drop (difficult to exchange heat) because the temperature of the second fluid is high. Therefore, in a cross section perpendicular to the flow direction of the first fluid of the honeycomb structure 10, it is preferable that the communication holes 16 are continuously provided in the adjacent first partition walls 12a in the area far from the discharge port of the second fluid. With this configuration, it is possible to reduce the circumferential bias of the temperature of the first fluid in the area where heat exchange between the first fluid and the second fluid is easy (i.e., the area far from the discharge port of the second fluid, for example, the area on the supply port side of the second fluid), and thus the heat recovery efficiency is further improved.

The number of communication holes 16 provided at each position of the first partition wall 12a and the second partition wall 12b is not particularly limited, and may be appropriately set according to the length in the flow path direction of the first fluid (the axial length of the honeycomb structure 10). For example, it is preferable that two or more communication holes 16 are provided in the flow path direction of the first fluid. With such a configuration, it is possible to reduce the radial and/or circumferential bias of the temperature of the first fluid flowing through the cells 15, thereby further improving the heat recovery efficiency.
Although the upper limit of the number of the communicating holes 16 is not particularly limited, if the number of the communicating holes 16 is too large, there is a risk of the strength of the honeycomb structure 10 decreasing. Therefore, the upper limit should be set according to the length in the flow path direction of the first fluid within a range in which the strength of the honeycomb structure 10 is ensured.

The diameter of the communication hole 16 provided in the first partition 12a is not particularly limited, and may be smaller than the distance between adjacent second partitions 12b and between adjacent second partitions 12b and the outer peripheral wall 11. Similarly, the diameter of the communication hole 16 provided in the second partition 12b may be smaller than the distance between adjacent first partitions 12a. Here, the diameter of the communication hole 16 means the maximum diameter of the shape of the communication hole 16 in the cross section of the first partition 12a or the second partition 12b parallel to the flow direction of the first fluid.

As shown in Fig. 5, a protrusion 17 may be provided between two communication holes 16 in the flow direction of the first fluid. By providing the protrusion 17, the surface area of the flow path of the first fluid is increased, and the heat recovery efficiency is further improved. Fig. 5 is a partially enlarged cross-sectional view of the partition wall 12 parallel to the flow direction of the first fluid (the axial direction of the honeycomb structure 10) and the thickness direction of the partition wall 12.
The protrusion 17 is not particularly limited, but may be a burr generated when forming the communication hole 16, or a protruding member may be joined between the two communication holes 16. When a protruding member is joined, it is preferably made of the same material as the partition wall 12.

The shape (outer shape) of the honeycomb structure 10 is not particularly limited and may be, for example, a circular cylinder, an elliptical cylinder, a rectangular cylinder, or other polygonal cylinder. Therefore, the outer shape of the honeycomb structure 10 in the cross section of Fig. 2 (i.e., the outer shape of the outer peripheral wall 11) may be a circle, an ellipse, a rectangle, or other polygonal shape.
In addition, the honeycomb structure 10 may be a hollow honeycomb structure 10a further having an inner peripheral wall 18 as shown in FIG. 6. FIG. 6 is a cross-sectional view of the hollow honeycomb structure 10a perpendicular to the flow path direction of the first fluid. In this case, the shape of the hollow portion is not particularly limited, and may be, for example, a cylinder, an elliptical cylinder, a square cylinder, or other polygonal cylinder. Therefore, the shape of the hollow portion in the cross section perpendicular to the flow path direction of the first fluid (i.e., the inner shape of the inner peripheral wall 18) may be a circle, an ellipse, a square, or other polygonal shape. The shape of the hollow honeycomb structure 10a and the shape of the hollow portion may be the same or different, but it is preferable that they are the same from the viewpoint of resistance to external impacts, thermal stress, and the like.

The thickness of the outer peripheral wall 11 (the outer peripheral wall 11 and the inner peripheral wall 18 in the case of the hollow honeycomb structure 10a) is preferably larger than the thickness of the partition walls 12. By adopting such a configuration, it is possible to increase the strength of the outer peripheral wall 11 (the outer peripheral wall 11 and the inner peripheral wall 18 in the case of the hollow honeycomb structure 10a), which is easily destroyed (e.g., cracked, broken, etc.) by an external impact, a thermal stress due to a temperature difference between the first fluid and the second fluid, etc.
The thicknesses of the outer peripheral wall 11 and the partition walls 12 (the outer peripheral wall 11, the partition walls 12 and the inner peripheral wall 18 in the case of the hollow honeycomb structure 10a) can be appropriately adjusted depending on the application. For example, when the heat exchange member 100 is used for general heat exchange applications, the thicknesses of the outer peripheral wall 11 and the inner peripheral wall 18 are preferably more than 0.3 mm and not more than 10 mm, more preferably 0.5 mm to 5 mm, and even more preferably 1 mm to 3 mm. When the heat exchange member 100 is used for heat storage applications, it is also preferable to set the thickness of the outer peripheral wall 11 to 10 mm or more to increase the heat capacity of the outer peripheral wall 11.
The thickness of the partition walls 12 is preferably 0.1 to 1 mm, and more preferably 0.2 to 0.6 mm. By making the thickness of the partition walls 12 0.1 mm or more, it is possible to ensure sufficient mechanical strength of the honeycomb structure 10. Furthermore, by making the thickness of the partition walls 12 1 mm or less, it is possible to suppress problems such as an increase in pressure loss due to a decrease in the opening area and a decrease in heat recovery efficiency due to a decrease in the contact area with the first fluid.

The outer peripheral wall 11 and partition walls 12 (in the case of the hollow honeycomb structure 10a, the outer peripheral wall 11, partition walls 12 and inner peripheral wall 18) are mainly composed of ceramics. "Mainly composed of ceramics" means that the mass ratio of ceramics to the total mass of the outer peripheral wall 11 and partition walls 12 (in the case of the hollow honeycomb structure 10a, the outer peripheral wall 11, partition walls 12 and inner peripheral wall 18) is 50 mass% or more.

The porosity of the outer peripheral wall 11 and partition walls 12 (in the case of a hollow honeycomb structure 10a, the outer peripheral wall 11, partition walls 12 and inner peripheral wall 18) is preferably 10% or less, more preferably 5% or less, and particularly preferably 3% or less. These porosities can also be 0%. By making these porosities 10% or less, the thermal conductivity can be improved.

The outer peripheral wall 11 and partition walls 12 (in the case of the hollow honeycomb structure 10a, the outer peripheral wall 11, partition walls 12, and inner peripheral wall 18) preferably contain SiC (silicon carbide), which has high thermal conductivity, as a main component. "Containing SiC (silicon carbide) as a main component" means that the mass ratio of SiC (silicon carbide) to the total mass of the outer peripheral wall 11 and partition walls 12 (in the case of the hollow honeycomb structure 10a, the outer peripheral wall 11, partition walls 12, and inner peripheral wall 18) is 50 mass% or more.

More specifically, the materials that can be used for the outer peripheral wall 11 and the partition walls 12 (the outer peripheral wall 11, the partition walls 12 and the inner peripheral wall 18 in the case of the hollow honeycomb structure 10a) include Si-impregnated SiC, (Si+Al)-impregnated SiC, metal composite SiC, recrystallized SiC, _Si3N4 , and SiC. Among these, it is preferable to use Si-impregnated SiC and (Si ₊ Al)-impregnated SiC because they can be manufactured inexpensively and have high thermal conductivity.

The cell density (i.e., the number of cells 15 per unit area) in the cross section of the honeycomb structure 10 perpendicular to the flow direction of the first fluid is not particularly limited and may be appropriately adjusted depending on the application, but is preferably in the range of 4 to 320 cells/ ^cm2 . By setting the cell density to 4 cells/cm2 or ^more , the strength of the partition walls 12, and therefore the strength and effective GSA (geometric surface area) of the honeycomb structure 10 itself can be sufficiently ensured. In addition, by setting the cell density to 320 cells/cm2 or ^less , an increase in pressure loss when the first fluid flows can be prevented.

The isostatic strength of the honeycomb structure 10 is preferably greater than 100 MPa, more preferably greater than 150 MPa, and even more preferably greater than 200 MPa. If the isostatic strength of the honeycomb structure 10 exceeds 100 MPa, the honeycomb structure 10 will have excellent durability. The isostatic strength of the honeycomb structure 10 can be measured in accordance with the method for measuring isostatic fracture strength stipulated in JASO standard M505-87, an automotive standard issued by the Society of Automotive Engineers of Japan.

The diameter (outer diameter) of the outer peripheral wall 11 in a cross section perpendicular to the flow direction of the first fluid is preferably 20 to 200 mm, more preferably 30 to 100 mm. By setting the diameter in this range, the heat recovery efficiency can be improved. When the outer peripheral wall 11 is not circular, the diameter of the maximum inscribed circle inscribed in the cross-sectional shape of the outer peripheral wall 11 is defined as the diameter of the outer peripheral wall 11.
In the case of the hollow honeycomb structure 10a, the diameter of the inner peripheral wall 18 in a cross section perpendicular to the flow direction of the first fluid is preferably 1 to 60 mm, and more preferably 2 to 30 mm. When the cross-sectional shape of the inner peripheral wall 18 is not circular, the diameter of the inner peripheral wall 18 is defined as the diameter of the maximum inscribed circle inscribed in the cross-sectional shape of the inner peripheral wall 18.

The thermal conductivity of the honeycomb structure 10 at 25°C is preferably 50 W/(m·K) or more, more preferably 100 to 300 W/(m·K), and even more preferably 120 to 300 W/(m·K). By setting the thermal conductivity of the honeycomb structure 10 within this range, the thermal conductivity is improved, and the heat within the honeycomb structure 10 can be efficiently transferred to the outside. The thermal conductivity value is measured by the laser flash method (JIS R1611-1997).

When exhaust gas is passed through the cells 15 of the honeycomb structure 10 as the first fluid, a catalyst may be supported on the partition walls 12 of the honeycomb structure 10. Supporting a catalyst on the partition walls 12 makes it possible to convert CO, NOx, HC, etc. in the exhaust gas into harmless substances through a catalytic reaction, and also makes it possible to use the reaction heat generated during the catalytic reaction for heat exchange. The catalyst preferably contains at least one element selected from the group consisting of precious metals (platinum, rhodium, palladium, ruthenium, indium, silver, and gold), aluminum, nickel, zirconium, titanium, cerium, cobalt, manganese, zinc, copper, tin, iron, niobium, magnesium, lanthanum, samarium, bismuth, and barium. The above elements may be contained as simple metals, metal oxides, or other metal compounds.

The covering member 20 is not particularly limited as long as it can cover the outer peripheral surface of the outer peripheral wall 11 of the honeycomb structure 10. For example, a tubular member can be used that fits onto the outer peripheral surface of the outer peripheral wall 11 of the honeycomb structure 10 and circumferentially covers the outer peripheral wall 11 of the honeycomb structure 10. In addition, from the viewpoint of a cushioning effect, an inorganic mat or the like may be interposed between the honeycomb structure 10 and the covering member 20.
In this specification, the term "fitting" refers to the honeycomb structure 10 and the covering member 20 being fixed in a mutually fitted state. Therefore, the fitting of the honeycomb structure 10 and the covering member 20 includes cases where the honeycomb structure 10 and the covering member 20 are fixed to each other by brazing, welding, diffusion bonding, etc., in addition to a fixing method based on fitting such as clearance fitting, interference fitting, and shrink fitting.

The covering member 20 can have an inner surface shape that corresponds to the outer wall 11 of the honeycomb structure 10. By having the inner surface of the covering member 20 directly contact the outer wall 11 of the honeycomb structure 10, the thermal conductivity is improved, and the heat within the honeycomb structure 10 can be efficiently transferred to the covering member 20.

From the viewpoint of increasing the heat recovery efficiency, it is preferable that the ratio of the area of the outer peripheral surface of the outer peripheral wall 11 of the honeycomb structure 10 that is circumferentially covered by the covering member 20 to the total area of the outer peripheral surface of the outer peripheral wall 11 of the honeycomb structure 10 is high. Specifically, the area ratio is preferably 80% or more, more preferably 90% or more, and even more preferably 100% (i.e., the entire outer peripheral surface of the outer peripheral wall 11 of the honeycomb structure 10 is circumferentially covered by the covering member 20).
In addition, the "outer wall 11" referred to here refers to a surface parallel to the flow direction of the first fluid in the honeycomb structure 10, and does not include surfaces (first end face 13 and second end face 14) perpendicular to the flow direction of the first fluid in the honeycomb structure 10.

From the viewpoint of manufacturability, the covering member 20 is preferably made of metal. In addition, if the covering member 20 is made of metal, it is also advantageous in that it can be easily welded to the outer tube 30 (casing) described below. For example, stainless steel, titanium alloy, copper alloy, aluminum alloy, brass, etc. can be used as the material for the covering member 20. Among these, stainless steel is preferred because of its high durability, reliability, and low cost.

For reasons of durability and reliability, the thickness of the covering member 20 is preferably 0.1 mm or more, more preferably 0.3 mm or more, and even more preferably 0.5 mm or more. For reasons of reducing thermal resistance and increasing thermal conductivity, the thickness of the covering member 20 is preferably 10 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less.

The length of the covering member 20 (the length in the flow path direction of the first fluid) is not particularly limited, and may be appropriately adjusted depending on the size of the honeycomb structure 10. For example, the length of the covering member 20 is preferably greater than the length of the honeycomb structure 10. Specifically, the length of the covering member 20 is preferably 5 mm to 250 mm, more preferably 10 mm to 150 mm, and further preferably 20 mm to 100 mm.
When the length of the covering member 20 is greater than the length of the honeycomb structure 10 , it is preferable that the honeycomb structure 10 be positioned at the center of the covering member 20 .

Next, a method for manufacturing the heat exchanger member 100 will be described. However, the method for manufacturing the heat exchanger member 100 is not limited to the manufacturing method described below.

First, a clay containing ceramic powder is extruded into a desired shape to produce a honeycomb molded body. At this time, by selecting an appropriate type of die and jig, the shape and density of the cells 15, the number, length and thickness of the partition walls 12, the shape and thickness of the outer peripheral wall 11, etc. can be controlled. The above-mentioned ceramics can be used as the material for the honeycomb molded body. For example, when manufacturing a honeycomb molded body mainly composed of a Si-impregnated SiC composite material, a binder and water or an organic solvent are added to a predetermined amount of SiC powder, the resulting mixture is kneaded to form a clay, and molded to obtain a honeycomb molded body of the desired shape. The obtained honeycomb molded body is then dried, and metal Si is impregnated and fired in a reduced pressure inert gas or vacuum to obtain a honeycomb structure 10.

The method for forming the communication hole 16 is not particularly limited, but may be mechanical processing, or manufacturing conditions may be selected so that a defect that will become the communication hole 16 is formed in the partition wall 12 .
When forming the communication holes 16 by machining, a plurality of honeycomb segments each having a short length in the flow path direction of the first fluid are produced, and the communication holes 16 are formed in these honeycomb segments by machining, and then the plurality of honeycomb segments are joined together. The honeycomb segments may be joined together using a bonding material or the like, but the honeycomb segments can be joined together without a bonding material by arranging the plurality of honeycomb segments on the covering member 20 and shrink fitting them together. When a bonding material is provided, a bonding material containing the same type of ceramic powder as the material used to produce the honeycomb formed body may be used.
As an example, Fig. 7 shows a partially enlarged perspective view of a honeycomb segment in which communicating holes 16 are formed by machining. This honeycomb segment is used to manufacture a hollow honeycomb structure 10a. The communicating holes 16 may be formed, for example, in the center (Fig. 7(a)) or end (Fig. 7(b)) of the partition walls 12 of the honeycomb segment.
The honeycomb segment may be a segment of a dried honeycomb formed body before firing, or a segment of the honeycomb structure 10 after firing.
The mechanical processing is not particularly limited, but for example, grinding, cutting, laser processing, water jet processing, electric discharge (EDM) processing, etc. can be used.
Furthermore, when providing a protrusion 17 between two communication holes 16 in the flow path direction of the first fluid, a protruding member may be bonded to a predetermined position after the communication holes 16 are formed.

As a method for generating defects that become the communicating holes 16 in the partition walls 12, for example, a method of controlling the slit width of the die or the particle size of the SiC powder to conditions that generate defects in the partition walls 12 may be used.
Also, defects may be generated in the partition walls 12 by including a pore-forming material in the clay. Specifically, a honeycomb molded body is manufactured by including a pore-forming material having a particle size larger than the thickness of the first partition walls 12a and smaller than the thickness of the second partition walls 12b in the clay, and the pore-forming material is removed during firing, so that defects (communicating holes 16) can be generated only in the first partition walls 12a. Conversely, a honeycomb molded body is manufactured by including a pore-forming material having a particle size smaller than the thickness of the first partition walls 12a and larger than the thickness of the second partition walls 12b in the clay, and the pore-forming material is removed during firing, so that defects (communicating holes 16) can be generated only in the second partition walls 12b. Of course, if a honeycomb formed body is produced by adding a pore-forming material having a particle size larger than the thickness of the first partition wall 12a and the second partition wall 12b to the clay, and the pore-forming material is removed during firing, it is also possible to create defects (communicating holes 16) in both the first partition wall 12a and the second partition wall 12b.
Furthermore, air bubbles may be intentionally mixed in when ceramic powder or the like is mixed to form a clay, thereby causing defects (communicating holes 16) in the partition walls 12 due to the air bubbles.

Next, the honeycomb structure 10 is shrink-fitted into the covering member 20, thereby covering the outer peripheral surface of the outer wall 11 of the honeycomb structure 10 with the covering member 20. Specifically, the covering member 20 is heated and expanded, the honeycomb structure 10 is inserted into the covering member 20, and then the covering member 20 is cooled and contracted, thereby fixing the honeycomb structure 10 within the covering member 20. As described above, the honeycomb structure 10 and the covering member 20 can be fitted together by a fixing method using fitting such as a clearance fit or an interference fit, as well as by shrink fitting, as well as brazing, welding, diffusion bonding, etc. In this way, the heat exchange member 100 can be obtained.

The heat exchange member 100 according to the embodiment of the present invention has one or more communication holes 16 in at least one of the first partition wall 12a and the second partition wall 12b, thereby improving the heat recovery efficiency.

(2) Heat Exchanger The heat exchanger according to the embodiment of the present invention has the above-mentioned heat exchange member 100. There are no particular limitations on the members other than the heat exchange member 100, and known members can be used. For example, the heat exchanger according to the embodiment of the present invention can include the heat exchange member 100 and an outer cylinder (casing) disposed at a distance from the outer periphery of the covering member 20 of the heat exchange member 100 so that the second fluid can flow around the outer periphery of the covering member 20.

Figure 8 is a cross-sectional view parallel to the flow direction of the first fluid in the honeycomb structure of a heat exchanger according to an embodiment of the present invention. Also, Figure 9 is a cross-sectional view of line b-b' of the heat exchanger shown in Figure 8, and is a cross-sectional view perpendicular to the flow direction of the first fluid in the honeycomb structure of a heat exchanger according to an embodiment of the present invention.

A heat exchanger 200 according to an embodiment of the present invention includes a heat exchange member 100 and an outer cylinder 30 arranged at a distance from the outer periphery of the covering member 20 of the heat exchange member 100 so that a second fluid can flow around the outer periphery of the covering member 20. The outer cylinder 30 has a supply pipe 31 and a discharge pipe 32 for the second fluid. In addition, it is preferable that the outer cylinder 30 circumferentially covers the entire outer periphery of the heat exchange member 100.
In the heat exchanger 200 having the above-mentioned structure, the second fluid flows into the outer casing 30 from the supply pipe 31. Next, while passing through the flow path of the second fluid, the second fluid exchanges heat with the first fluid flowing through the cells 15 of the honeycomb structure 10 via the covering member 20 of the heat exchange element 100, and is then discharged from the discharge pipe 32 of the second fluid. The outer peripheral surface of the covering member 20 of the heat exchange element 100 may be covered with a member for adjusting the heat transfer efficiency.

The second fluid is not particularly limited, but when the heat exchanger 200 is mounted on an automobile, the second fluid is preferably water or antifreeze (LLC as defined in JIS K2234:2006). Regarding the temperatures of the first and second fluids, it is preferable that the temperature of the first fluid is greater than the temperature of the second fluid. This is because the covering member 20 of the heat exchange member 100 does not expand at low temperatures, and the honeycomb structure 10 expands at higher temperatures, making it difficult for the fitting between the two to loosen. In particular, when the fitting between the honeycomb structure 10 and the covering member 20 is a shrink fit, the risk of the fitting loosening and the honeycomb structure 10 falling out can be minimized.

The inner surface of the outer tube 30 is preferably fitted with the outer peripheral surface of the covering member 20 of the heat exchange member 100. In this way, the outer peripheral surface of the covering member 20 at both ends in the flow direction of the first fluid is in close circumferential contact with the inner surface of the outer tube 30, and the second fluid is prevented from leaking to the outside. Methods for bringing the outer peripheral surface of the covering member 20 into close contact with the inner surface of the outer tube 30 include, but are not limited to, welding, diffusion bonding, brazing, mechanical fastening, and the like. Among these, welding is preferred because it has high durability and reliability and can also improve structural strength.

From the viewpoints of thermal conductivity and manufacturability, the outer cylinder 30 is preferably made of a metal. Examples of metals that can be used include stainless steel, titanium alloys, copper alloys, aluminum alloys, and brass. Among these, stainless steel is preferred because it is inexpensive and has high durability and reliability.

For reasons of durability and reliability, the thickness of the outer cylinder 30 is preferably 0.1 mm or more, more preferably 0.5 mm or more, and even more preferably 1 mm or more. From the standpoints of cost, volume, weight, etc., the thickness of the outer cylinder 30 is preferably 10 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less.

The outer tube 30 may be an integrally molded product, or may be a joined member formed from two or more members. When the outer tube 30 is a joined member formed from two or more members, the design freedom of the outer tube 30 can be increased.

The positions of the supply pipe 31 and the discharge pipe 32 of the second fluid are not particularly limited, and can be changed appropriately in the axial and circumferential directions taking into consideration the installation location of the heat exchanger 200, the piping position, the heat exchange efficiency, etc. For example, the supply pipe 31 and the discharge pipe 32 of the second fluid can be provided at positions corresponding to both axial ends of the honeycomb structure 10. In addition, the supply pipe 31 and the discharge pipe 32 of the second fluid may extend in the same direction or in different directions.

When the honeycomb structure 10 of the heat exchanger 200 according to an embodiment of the present invention is a hollow honeycomb structure 10a, the heat exchanger 200 may further include an inner tube in the hollow portion (the inner side of the inner wall 18) and an opening/closing valve provided in the inner tube.
The inner tube may have a through hole formed therein for introducing the first fluid into the cells 15 of the honeycomb structure 10, and the through hole may branch the flow of the first fluid into two (the cells 15 of the honeycomb structure 10 and the hollow portion).
The on-off valve can use its on-off mechanism to control the amount of the first fluid flowing through the hollow portion of the honeycomb structure 10. In particular, the on-off valve can selectively introduce the first fluid into the cells 15 of the honeycomb structure 10 through the through holes by blocking the flow of the first fluid inside the inner tube during heat exchange between the first fluid and the second fluid, thereby making it possible to efficiently exchange heat between the first fluid and the second fluid.

The through holes in the inner tube may be formed around the entire circumference of the inner tube, or may be formed at a partial position of the inner tube (for example, only the upper, middle, or lower part). The shape of the through holes may be various shapes such as circular, elliptical, or rectangular.

In the heat exchanger 200 having such a structure, the first fluid can be circulated inside the inner cylinder. At this time, when the on-off valve is closed, the air flow resistance inside the inner cylinder increases, and the first fluid selectively flows into the cell 15 through the through hole. On the other hand, when the on-off valve is open, the air flow resistance inside the inner cylinder decreases, and the first fluid selectively flows into the inner cylinder in the hollow part. Therefore, by controlling the opening and closing of the on-off valve, the amount of the first fluid flowing into the cell 15 can be adjusted. Note that the first fluid flowing through the inner cylinder in the hollow part hardly contributes to heat exchange with the second fluid, so the path of this first fluid functions as a bypass path when it is desired to suppress the heat recovery of the first fluid. In other words, when it is desired to suppress the heat recovery of the first fluid, the on-off valve can be opened.

Next, a description will be given of a manufacturing method of the heat exchanger 200. However, the manufacturing method of the heat exchanger 200 is not limited to the manufacturing method described below.
The heat exchanger 200 can be manufactured by disposing and joining the outer tube 30 at a distance from the radial outside of the covering member 20 of the heat exchange member 100 so that the second fluid can flow around the outer periphery of the covering member 20. Specifically, both ends of the covering member 20 of the heat exchange member 100 are joined to the inner surface of the outer tube 30. As described above, there are various joining methods including fitting. If necessary, the joining points can be joined by welding or the like. As a result, the outer tube 30 that circumferentially covers the outer periphery of the covering member 20 is formed, and a flow path for the second fluid is formed between the outer periphery of the covering member 20 and the inner surface of the outer tube 30. In this manner, the heat exchanger 200 can be obtained.
Furthermore, when the honeycomb structure 10 is a hollow honeycomb structure 10a, an inner cylinder provided with an on-off valve may be inserted into the inner peripheral wall 18 of the hollow honeycomb structure 10a and fitted by shrink fitting. As described above, the fitting between the inner peripheral wall 18 of the hollow honeycomb structure 10a and the inner cylinder may be performed by a fixing method based on fitting, such as a clearance fit or an interference fit, in addition to shrink fitting, or further by brazing, welding, diffusion bonding, or the like.

The heat exchanger 200 according to the first embodiment of the present invention is equipped with the above-mentioned heat exchange member 100, and therefore can improve the heat recovery efficiency.

REFERENCE SIGNS LIST 10 Honeycomb structure 10a Hollow honeycomb structure 11 Outer peripheral wall 12 Partition wall 12a First partition wall 12b Second partition wall 13 First end face 14 Second end face 15 Cell 16 Communication hole 17 Projection 18 Inner peripheral wall 20 Covering member 30 Outer cylinder 31 Supply pipe 32 Discharge pipe 100 Heat exchange member 200 Heat exchanger

Claims (11)

A honeycomb structure having an outer peripheral wall and partition walls disposed inside the outer peripheral wall and defining a plurality of cells that serve as flow paths for a first fluid extending from a first end surface to a second end surface;
A covering member that covers an outer peripheral surface of the outer peripheral wall,
In a cross section of the honeycomb structure perpendicular to a flow path direction of the first fluid, the partition walls include one or more first partition walls extending in a radial direction and one or more second partition walls extending in a circumferential direction,
The heat exchange member, wherein the first partition wall has one or more communication holes. The heat exchange element according to claim 1 , wherein the communication holes are configured to allow the first fluid to flow between adjacent cells separated by the first partition wall . The heat exchange element according to claim 1 or 2, wherein the second partition wall has one or more communication holes. The heat exchange element according to claim 1 , wherein the communicating holes have a circular, elliptical or polygonal shape. The heat exchange element according to claim 3 , wherein the communication holes are provided in all of the two or more second partition walls located between adjacent first partition walls in the cross section and in the radial direction. The heat exchange element according to claim 3 , wherein the communication hole is provided in each region in the circumferential direction of one of the second partition walls located between adjacent ones of the first partition walls in the cross section. The heat exchange element according to claim 1 , wherein two or more communication holes are provided in a flow path direction of the first fluid. The heat exchange element according to claim 7 , wherein a protrusion is provided between two of the communication holes in the flow direction of the first fluid. The heat exchange element according to claim 1 , wherein a part of the first partition wall has one or more communication holes. The heat exchange member according to any one of claims 1 to 9 , wherein the honeycomb structure is a hollow honeycomb structure further having an inner peripheral wall. The heat exchange member according to any one of claims 1 to 10 ,
and an outer cylinder disposed radially outwardly of the covering member at a distance therefrom so that a second fluid can flow around the outer periphery of the covering member.