Heat exchange member, heat exchanger using the same, and method for manufacturing the heat exchange member

Abstract

The present application provides a heat exchange member having excellent heat exchange performance. The heat exchange member of an embodiment of the present application includes: a honeycomb structure having a partition wall and a peripheral wall, the partition wall defining a cell, the cell forming a flow path of a first fluid extending from a first end surface to a second end surface; and a coating member coating the peripheral wall of the honeycomb structure. The partition wall and the peripheral wall contain ceramic as a main component, and the RPc of the surface of the peripheral wall, as defined by JIS B 0601:2013, is 55 pks / cm or more.

Description

Technical Field

[0001] The present invention relates to a heat exchange component, a heat exchanger using the heat exchange component, and a method for manufacturing the heat exchange component. Background Technology

[0002] In recent years, there has been a demand for improving fuel efficiency in automobiles. In particular, to prevent further deterioration in fuel consumption when the engine is still cold during startup, a system is needed that quickly warms up coolant, engine oil, and ATF (Automatic Transmission Fluid) to reduce friction losses. Additionally, a system is also needed that heats the catalyst to quickly activate catalysts used for exhaust gas purification.

[0003] In the aforementioned system, the use of a heat exchanger was discussed, for example. A heat exchanger is a device including a heat exchange component configured to allow a first fluid to flow internally and a second fluid to flow externally, thereby facilitating heat exchange between the first and second fluids. In the aforementioned heat exchanger, heat can be effectively utilized, for example, by exchanging heat from a high-temperature first fluid (e.g., exhaust gas) to a low-temperature second fluid (e.g., cooling water). As a heat exchanger for recovering heat from high-temperature gases such as automobile exhaust, heat exchangers have been developed in recent years that are configured to house a heat exchange component having a columnar honeycomb structure within a frame (shell), allowing the first fluid to flow through the compartments of the honeycomb structure and the second fluid to flow within the shell on the outer peripheral surface of the heat exchange component. As a heat exchange component with a honeycomb structure, a heat exchanger with a columnar honeycomb structure has been proposed. In a cross-section perpendicular to the flow path direction of the first fluid (the direction of compartment extension), the columnar honeycomb structure has a first partition extending radially from the center outwards, and a second partition extending circumferentially (Patent Document 1). Additionally, a heat exchange component with a hollow (donut-shaped) columnar honeycomb structure has a hollow region that functions as a bypass path for exhaust gas (Patent Document 2). While heat exchange components with the aforementioned columnar honeycomb structures are very useful, there is a continued demand for further improvements in heat exchange performance.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 6075381

[0007] Patent Document 2: International Publication No. 2017 / 069265 Summary of the Invention

[0008] The main objective of this invention is to provide a heat exchange component with excellent heat exchange performance. Another objective of this invention is to provide a heat exchanger using the heat exchange component and a method for manufacturing the heat exchange component.

[0009] The heat exchange component according to an embodiment of the present invention comprises: a honeycomb structure having partitions and an outer peripheral wall, the partitions defining compartments that extend from a first end face to a second end face to form a flow path for a first fluid; and a coating component that coats the outer peripheral wall of the honeycomb structure. The partitions and the outer peripheral wall contain ceramic as the main component, and the surface area of ​​the outer peripheral wall, as specified in JIS B 0601:2013, has an RPc of 55 pks / cm or higher.

[0010] In one embodiment, the RPc of the inner circumferential surface of the covered component is 45 pks / cm or more.

[0011] In one embodiment, the maximum cross-sectional height Rt of the surface of the outer peripheral wall, as specified in JIS B 0601:2013, is 75 μm or less.

[0012] In one embodiment, the partition wall and the outer peripheral wall are made of ceramic containing silicon carbide as the main component.

[0013] In one embodiment, the honeycomb structure has the aforementioned compartments across its entire cross-section in a direction perpendicular to the flow path direction of the first fluid. In another embodiment, the honeycomb structure has a hollow region at the center of its cross-section in a direction perpendicular to the flow path direction of the first fluid.

[0014] According to another aspect of the present invention, a heat exchanger is provided. The heat exchanger includes: the aforementioned heat exchange component; and an outer cylinder, which is separately disposed outside the heat exchange component, and a flow path for a second fluid is formed between the outer cylinder and the aforementioned covering component of the heat exchange component.

[0015] According to another aspect of the present invention, a method for manufacturing the above-mentioned heat exchange component is provided. This method includes: using a grinding stone with a grit size of 90 or higher and a diameter of 20 mm or higher, and machining the outer peripheral wall surface at a circumferential speed of 3.0 m / s or higher.

[0016] Invention Effects

[0017] According to embodiments of the present invention, a heat exchange component with excellent heat exchange performance can be realized. Attached Figure Description

[0018] Figure 1This is a simplified cross-sectional view of a heat exchange component according to one embodiment of the present invention, in a direction parallel to the flow path direction of the first fluid.

[0019] Figure 2 This is a simplified cross-sectional view of a heat exchange component according to one embodiment of the present invention, in a direction orthogonal to the flow path direction of the first fluid. Figure 1 (Simplified cross-sectional view at line II-II).

[0020] Figure 3 This is a simplified cross-sectional view of the heat exchange component of another embodiment of the present invention in a direction orthogonal to the flow path direction of the first fluid.

[0021] Figure 4 This is a simplified cross-sectional view of a heat exchanger according to one embodiment of the present invention, in a direction orthogonal to the flow path direction of the first fluid. Detailed Implementation

[0022] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings; however, the present invention is not limited to these embodiments.

[0023] A. Heat exchange components

[0024] A-1. Overall Structure of Heat Exchange Components

[0025] Figure 1 This is a simplified cross-sectional view of a heat exchange component according to one embodiment of the present invention, in a direction parallel to the flow path direction of the first fluid. Figure 2 yes Figure 1 A simplified cross-sectional view of the heat exchange component at line II-II. The heat exchange component 100 illustrated in the figure includes: a honeycomb structure 10 having partitions 16 and an outer peripheral wall 18, the partitions 16 defining compartments 14 extending from a first end face 12a to a second end face 12b to form a flow path for a first fluid; and a covering component 20 covering the outer peripheral wall 18 of the honeycomb structure 10. The partitions 16 and the outer peripheral wall 18 contain ceramic as the main component.

[0026] In embodiments of the present invention, the RPc of the outer peripheral wall surface (outer peripheral surface of the outer peripheral wall) 18a, as specified by JIS B0601:2013, is 55 pks / cm or more, preferably 75 pks / cm or more, more preferably 80 pks / cm or more, and even more preferably 90 pks / cm or more. The upper limit of RPc can be, for example, 115 pks / cm. With an RPc in this range for the outer peripheral wall surface, excellent heat exchange performance can be achieved. It can be inferred that such an effect can be achieved as described below. However, this is merely a conjecture and does not limit the effect and mechanism of the embodiments of the present invention. RPc is one of the indicators of surface roughness, representing the number of peaks present in a reference range. By setting RPc to a specified value or higher as described above, the number of reliable contact points between the outer peripheral wall surface 18a of the honeycomb structure 10 and the inner peripheral surface 20a of the covered component 20 increases. This increase in contact points improves heat transfer from the outer peripheral wall to the covered component, thereby enabling a heat exchange component with improved heat exchange performance. Furthermore, as described later, in embodiments of the present invention, the maximum cross-sectional height Rt and the arithmetic mean roughness Ra are typically below a specified value. That is, although the number of peaks on the outer peripheral wall surface of the honeycomb structure is relatively large, there are no prominent high peaks, and the overall texture of the outer peripheral wall surface is not particularly rough. As a result, the outer peripheral wall surface 18a of the honeycomb structure 10 and the inner peripheral surface 20a of the covered component 20 not only reliably contact each other through a large number of contact points, but also the overall (i.e., the overall contact between the surfaces) is increased. Therefore, according to embodiments of the present invention, the heat transfer between the honeycomb structure (outer peripheral wall surface) and the covered component (inner peripheral surface) is improved, resulting in a heat exchange component with excellent heat exchange performance.

[0027] The RPc of the inner circumferential surface 20a of the coated component 20 is preferably 45 pks / cm or more, more preferably 80 pks / cm or more, and even more preferably 120 pks / cm or more. The upper limit of RPc can be, for example, 150 pks / cm. If the RPc of the inner circumferential surface of the coated component is in such a range, then through the synergistic effect with the effect of setting the RPc of the outer circumferential wall surface to the above range, superior heat exchange performance can be achieved.

[0028] The maximum cross-sectional height (the sum of the maximum peak height and the maximum valley depth) Rt of the outer peripheral wall surface 18a, as specified in JIS B 0601:2013, is preferably 75 μm or less, more preferably 55 μm or less, and even more preferably 45 μm or less. The lower limit of Rt is not particularly limited; for example, it can be 10 μm. If the Rt of the outer peripheral wall surface is within such a range, superior heat exchange performance can be achieved through the synergistic effect of setting the RPc of the outer peripheral wall surface to the aforementioned range. The following can be inferred (however, similarly to the case of RPc, this does not limit the effects and mechanisms of the embodiments of the present invention). If the maximum cross-sectional height is too high, the number of contact points may decrease even if the RPc (i.e., the number of peaks) is above a specified value. Therefore, by keeping the maximum cross-sectional height below a specified value, a reliable number of contact points, as achieved by setting the RPc to a specified value or higher, can be ensured. Furthermore, integral contact between the outer peripheral wall surface of the honeycomb structure and the inner peripheral surface of the covered component can be ensured. It should be noted that the manufacturing method described in section B below can be used to produce a honeycomb structure having an outer peripheral wall surface that simultaneously satisfies the above-mentioned Rt and RPc.

[0029] The arithmetic mean roughness Ra of the outer peripheral wall surface 18a, as specified in JIS B 0601:2013, is preferably 9.5 μm or less, more preferably 7.5 μm or less, and even more preferably 4.5 μm or less. The lower limit of Ra is not particularly limited; for example, it can be 0.5 μm. If the Ra of the outer peripheral wall surface is within such a range, superior heat exchange performance can be achieved through the synergistic effect of setting the RPc and Rt of the outer peripheral wall surface to the aforementioned range. That is, in a state where there are many reliable contact points between the outer peripheral wall surface of the honeycomb structure formed by the peaks and the inner peripheral surface of the covered component, the overall (i.e., the overall contact between surfaces) can also be increased. As a result, heat transfer between the honeycomb structure (outer peripheral wall surface) and the covered component (inner peripheral surface) can be improved.

[0030] The following describes the honeycomb structure and the covered components that constitute the heat exchange components.

[0031] A-2. Honeycomb structure

[0032] like Figure 1 and Figure 2As shown, the honeycomb structure 10 has a partition wall 16 and an outer peripheral wall 18. The partition wall 16 defines a compartment 14 that extends from a first end face 12a to a second end face 12b, forming a flow path for the first fluid. In the heat exchange component 100, when the first fluid flows within the compartment 14 of the honeycomb structure 10 and the second fluid flows outside the covering component 20 (described later), heat exchange occurs between the first fluid and the second fluid via the outer peripheral wall 18 of the honeycomb structure 10 and the covering component 20. It should be noted that... Figure 1 In this context, the first fluid can flow in either the left or right direction on the paper. Any suitable liquid or gas can be used as the first fluid, depending on the purpose. For example, in the case of a heat exchange component 100 used in a heat exchanger of an automobile, the first fluid is preferably exhaust gas.

[0033] The cross-sectional shape of the honeycomb structure 10 in the direction orthogonal to the flow direction of the first fluid can be any suitable shape, as long as the first fluid flows from the first end face 12a to the second end face 12b within the compartment 14. Specific examples include circles, ellipses, quadrilaterals, or other polygons. In one embodiment, the honeycomb structure 10 can be cylindrical with a circular cross-section.

[0034] The compartment 14 has any suitable cross-sectional shape in a direction orthogonal to the flow direction of the first fluid. In the example shown, the first partition wall 16a and the second partition wall 16b are orthogonal to each other, and the compartment 14 is defined as having a quadrilateral (square) cross-sectional shape except for the portion in contact with the outer peripheral wall 18. Besides a square, the cross-sectional shape of the compartment 14 can be a triangle, a pentagon, a polygon, or more than one hexagon. In another embodiment (not shown), the compartment can be defined by a first partition wall extending radially from the center of the cross-section in a direction orthogonal to the flow direction of the first fluid, and a second partition wall extending circumferentially. The cross-sectional shape and dimensions of the compartment (except for the portion in contact with the outer peripheral wall) can be all the same, or at least some of them can be different.

[0035] The thickness of the partition 16 can be appropriately set according to the purpose. The thickness of the partition 16 is, for example, 0.1 mm to 1.0 mm, or, for example, 0.2 mm to 0.6 mm. If the thickness of the partition is within such a range, the mechanical strength of the honeycomb structure can be sufficient, and the opening area (the total area of ​​the compartments in the cross section) can be sufficient.

[0036] The density of septum 16 can be appropriately set according to the purpose. For example, the density of septum 16 can be 0.5 g / cm³. 3 ~5.0g / cm 3If the density of the partition walls falls within this range, the honeycomb structure (resulting in heat exchange components) can be made lightweight while maintaining sufficient mechanical strength and thermal conductivity. The density can be determined using, for example, the Archimedes method.

[0037] In one embodiment, the thickness of the outer peripheral wall 18 is greater than the thickness of the partition wall 16. With this configuration, damage to the outer peripheral wall (e.g., cracks, fissures) caused by external forces (e.g., external impacts, thermal stress caused by the temperature difference between the first and second fluids) can be suppressed. When the heat exchange component is used for general heat exchange applications, the thickness of the outer peripheral wall 18 is, for example, 0.3 mm to 10 mm, or, for example, 0.5 mm to 5 mm. When the heat exchange component is used for heat storage applications, by making the thickness of the outer peripheral wall, for example, 10 mm or more, the heat capacity can be increased.

[0038] As described above, the partition wall 16 and the outer peripheral wall 18 contain ceramic as a main component. In this specification, "containing ceramic as a main component" means that the ceramic accounts for more than 50% of the total mass of the partition wall 16 and the outer peripheral wall 18.

[0039] The porosity of the partition wall 16 and the outer peripheral wall 18 is preferably 10% or less, more preferably 5% or less, and even more preferably 3% or less. The porosity can be, for example, 0%. If the porosity of the partition wall and the outer peripheral wall is within such a range, the thermal conductivity of the honeycomb structure can be improved.

[0040] The partition wall 16 and the outer peripheral wall 18 are preferably made of ceramic containing silicon carbide as the main component. The partition wall 16 and the outer peripheral wall 18 may contain silicon carbide in a proportion of, for example, 50% by mass or more relative to the total mass.

[0041] Specific examples of silicon carbide include: SiC, Si-impregnated SiC, (Si+Al)-impregnated SiC, metal composite SiC, recrystallized SiC, and Si3N4. Si-impregnated SiC and (Si+Al)-impregnated SiC are preferred because they are inexpensive and have high thermal conductivity. It should be noted that in this specification, the term "SiC" refers not only to pure SiC but also to SiC containing unavoidable impurities.

[0042] Figure 2 The compartment density in the cross-section (i.e., the number of compartments per unit area) can be appropriately set according to the purpose. For example, the compartment density can be 4 compartments / cm². 2 ~320 compartments / cm 2 If the cell density is within this range, the strength and effective GSA (geometric surface area) of the honeycomb structure can be adequately ensured, and pressure loss during the first fluid flow can be suppressed.

[0043] For the cellular structure 10, such as Figure 2 As shown, the entire cross-section in the direction perpendicular to the flow path direction of the first fluid may have a compartment 14; as Figure 3 As shown, a hollow region 19 can also be present at the center of the cross-section. When the honeycomb structure has a hollow region, the hollow region can function as a bypass passage for the first fluid. With this configuration, a heat exchange component (resulting in a heat exchanger) that combines heat recovery and insulation properties can be realized. When the honeycomb structure has a hollow region, it has an outer peripheral wall 18, an inner peripheral wall 17, and a partition wall 16 disposed between the outer peripheral wall 18 and the inner peripheral wall 17, dividing and forming multiple compartments 14. These compartments 14 extend from the first end face 12a to the second end face 12b, forming a flow path for the first fluid. When the honeycomb structure has a hollow region, any suitable shape can be used for the shape of the hollow region. Specific examples include circles, ellipses, quadrilaterals, or other polygons. The shape of the hollow region can be the same as or different from the shape of the honeycomb structure. Preferably, the shape of the hollow region is as follows: Figure 3 The shape shown is the same as that of a honeycomb structure. With this configuration, good durability can be achieved against external impacts and thermal stress caused by the temperature difference between the first and second fluids. Furthermore, the diameter of the inner peripheral wall in the cross-section orthogonal to the flow direction of the first fluid is preferably 1 mm to 100 mm, more preferably 2 mm to 70 mm. If the cross-sectional shape of the inner peripheral wall is not circular, the diameter of the largest inscribed circle internally tangent to the cross-sectional shape of the inner peripheral wall is set as the diameter of the inner peripheral wall. It should be noted that the structure of the inner peripheral wall is as described above for the outer peripheral wall and the partition wall, and the thickness of the inner peripheral wall can be the same as the thickness of the outer peripheral wall.

[0044] The isostatic compressive strength of the honeycomb structure is preferably 5 MPa or more, more preferably 10 MPa or more, and even more preferably 100 MPa or more. With this configuration, a honeycomb structure with excellent durability can be manufactured. The isostatic compressive strength can be measured according to the automotive standard issued by the Japan Automobile Manufacturers Association, namely JASO Standard M505-87.

[0045] Figure 2 The diameter of the honeycomb structure in the cross-section can be appropriately set according to the purpose. The diameter of the honeycomb structure can be, for example, 20mm to 200mm, or, for example, 30mm to 100mm. If the diameter of the honeycomb structure is within this range, the heat recovery efficiency can be improved. It should be noted that if the cross-sectional shape of the honeycomb structure is not circular, the diameter of the largest inscribed circle that is inscribed within the cross-sectional shape (e.g., a polygon) of the honeycomb structure can be set as the diameter of the honeycomb structure.

[0046] The length of the honeycomb structure can be appropriately set according to the purpose. The length of the honeycomb structure can be, for example, 3mm to 200mm, or, for example, 5mm to 100mm, or, for example, 10mm to 50mm.

[0047] The thermal conductivity of the honeycomb structure at 25°C is preferably 50 W / (m·K) or higher, more preferably 100 W / (m·K) to 300 W / (m·K), and even more preferably 120 W / (m·K) to 300 W / (m·K). If the thermal conductivity is within this range, the thermal conductivity is good, enabling efficient transfer of heat (essentially the first fluid) within the honeycomb structure to the outside (e.g., the second fluid). It should be noted that the thermal conductivity can be determined using JIS R 1611-1997 (laser flash method).

[0048] When the exhaust gas flows into compartment 14 as the first fluid, a catalyst can be supported on the partition wall 16. By supporting the catalyst on the partition wall 16, CO and NO in the exhaust gas can be separated. x Hydrocarbons and other substances can be transformed into harmless substances through catalytic reactions, and the heat generated during the catalytic reaction can be used for heat exchange. Catalysts may contain, for example, noble metals (e.g., platinum, rhodium, palladium, ruthenium, indium, silver, gold), aluminum, nickel, zirconium, titanium, cerium, cobalt, manganese, zinc, copper, tin, iron, niobium, magnesium, lanthanum, samarium, bismuth, barium, or combinations thereof. These elements may be contained in the form of elemental metals, metal oxides, or other metal compounds.

[0049] A-3. Covered components

[0050] As the covering component 20, any suitable configuration can be used as long as it can cover the outer peripheral wall 18 of the honeycomb structure 10. For example, the covering component 20 can be a tubular component that fits into the outer peripheral wall 18 of the honeycomb structure 10 and surrounds it. In this specification, "fitting" means that the honeycomb structure and the covering component are fixed in a mutually fitted and mated state. Therefore, the term "fitting" in the context of the honeycomb structure and the covering component includes not only the state of fixation using fits such as clearance fits, interference fits, and thermo-press fits, but also the state of fixation using brazing, welding, diffusion bonding, etc.

[0051] The covering component 20 may have an inner surface shape corresponding to the outer peripheral wall 18 of the honeycomb structure 10. By having the inner peripheral surface of the covering component 20 in direct contact with the outer peripheral wall 18 of the honeycomb structure 10, and by making the RPc of the outer peripheral wall surface of the honeycomb structure and / or the inner peripheral surface of the covering component within the range described in item A-1 above, the heat transfer is very good, and the heat (which is essentially the first fluid) within the honeycomb structure can be transferred very efficiently to the covering component.

[0052] The higher the proportion of the area of ​​the outer peripheral wall 18 of the honeycomb structure 10 surrounded by the covering member 20 relative to the total area of ​​the outer peripheral wall 18, the better. Such a configuration improves heat recovery efficiency. This proportion is preferably 80% or more, more preferably 90% or more, and even more preferably 100% (i.e., the entire outer peripheral wall 18 of the honeycomb structure 10 is surrounded by the covering member 20). It should be noted that the term "area of ​​the outer peripheral wall 18" as used herein refers to the area in the direction parallel to the flow path direction of the first fluid, excluding the areas at the first and second end faces.

[0053] The covered component 20 is preferably made of metal. This configuration results in excellent manufacturing efficiency and facilitates easy installation (e.g., welding) to the outer cylinder (shell) when manufacturing the heat exchanger (described later). Examples of materials that constitute the covered component include stainless steel, titanium alloy, copper alloy, aluminum alloy, and brass. Stainless steel is preferred due to its high durability, reliability, and low cost.

[0054] The thickness of the coated component 20 can be, for example, 0.1 mm to 10 mm, or, for example, 0.3 mm to 5 mm, or, for example, 0.5 mm to 3 mm. If the thickness of the coated component is within such a range, an excellent balance between durability, reliability, and thermal conductivity can be achieved.

[0055] The length of the covering component 20 can be appropriately set according to the purpose, the length of the honeycomb structure 10, etc. The length of the covering component can be, for example, 5mm to 250mm, or, for example, 10mm to 150mm, or, for example, 20mm to 100mm. Preferably, the length of the covering component 20 is greater than the length of the honeycomb structure 10. In this case, the honeycomb structure can be positioned in the center of the covering component (so that the honeycomb structure is not exposed from the covering component).

[0056] B. Manufacturing method of heat exchange components

[0057] The manufacturing method of the heat exchange component according to an embodiment of the present invention includes: using a grinding stone with a grit size of 100 or higher and a diameter of 20 mm or higher, and machining the outer peripheral wall surface of a honeycomb structure (which is essentially its precursor) at a circumferential speed of 6.0 m / s or higher. According to this manufacturing method, an outer peripheral wall surface 18a having the RPc described in claim A-1 above can be formed in the honeycomb structure 10. If necessary, the inner peripheral surface of the covered component can be further machined. Accordingly, an inner peripheral surface 20a having the RPc described in claim A-1 above can be formed.

[0058] The RPc can be adjusted by appropriately combining and adjusting the grit size, diameter, and circumferential speed of the grinding stone. For example, when the diameter and grit size of the grinding stone are small, increasing the rotational speed can form an outer peripheral wall surface 18a with the desired RPc. Conversely, for example, if the diameter of the grinding stone is increased, an outer peripheral wall surface 18a with the desired RPc can be formed with a smaller grit size and rotational speed.

[0059] More specifically, when the grit size of the grinding stone is, for example, 90 to 140, and the diameter of the grinding stone is, for example, 20 mm to 100 mm, preferably 20 mm to 60 mm, the rotational speed of the grinding stone is preferably 3000 rpm or more, more preferably 4000 rpm to 7000 rpm. In this case, the circumferential speed of the grinding stone is, for example, 3 m / s to 15 m / s. When the grit size of the grinding stone is, for example, 100 or more, preferably 120 or more, and the diameter of the grinding stone is, for example, 150 mm or more, preferably 200 mm to 400 mm, the rotational speed of the grinding stone is preferably 3000 rpm or less, more preferably 1200 rpm to 2000 rpm. In this case, the circumferential speed of the grinding stone is, for example, 20 m / s to 35 m / s. In all cases, the depth of cut of the grinding stone is, for example, 0.1 mm to 0.4 mm.

[0060] Preferably, the cutting process is performed using a grinding stone while rotating the workpiece (essentially a precursor of a honeycomb structure) to be cut. The rotational speed of the workpiece is, for example, 100 rpm to 500 rpm, preferably 150 rpm to 300 rpm.

[0061] It should be noted that the following method can be used to fabricate a honeycomb structure. First, a blank containing ceramic powder is extruded and molded into the desired shape to create a honeycomb molded body. The ceramic described in section A-2 above can be used as the forming material for the honeycomb molded body. For example, in the case of fabricating a honeycomb structure with Si-impregnated SiC composite material as the main component, a binder and water or organic solvent are added to a specified amount of SiC powder to obtain a mixture. This mixture is then kneaded to form a blank, which is then molded to obtain a honeycomb molded body of the desired shape. Next, the obtained honeycomb molded body is dried and processed to a specified external dimension to obtain a dried honeycomb body. This dried honeycomb body is then fired in a reduced-pressure inert gas or vacuum to impregnate the dried honeycomb body with metallic Si, thereby obtaining a honeycomb structure. The grinding stone cutting process can be performed before firing (after drying and dimensional processing) or after firing.

[0062] C. Heat exchanger

[0063] Figure 4 This is a simplified cross-sectional view of a heat exchanger according to one embodiment of the present invention, in a direction orthogonal to the flow path direction of the first fluid. The heat exchanger 200 illustrated in the figure includes: Figure 1 and Figure 2 The heat exchange component 100 is shown; and an outer cylinder (shell) 120 is disposed separately from the heat exchange component 100 on the outside of the heat exchange component 100, and a flow path 140 for the second fluid is formed between the outer cylinder (shell) 120 and the covering component 20 of the heat exchange component 100. It should be noted that the illustrated example uses... Figure 1 and Figure 2 The heat exchange component 100 shown is not applicable; however, any suitable heat exchange component from the embodiments of the present invention described in items A and B above can be used as the heat exchange component. For example, it can be used... Figure 3 The heat exchange component 102 shown.

[0064] For the outer cylinder 120, typically, the cylindrical portion 121 surrounds the covered component 20, preferably surrounding the entire heat exchange component 100. The outer cylinder 120 has: an inlet 122 for the second fluid, an inlet conduit 123 connecting the inlet 122 and the cylindrical portion 121, an outlet 124 for the second fluid, and an outlet conduit 125 connecting the outlet 124 and the cylindrical portion 121. The second fluid flows in from the inlet 122, passes through the inlet conduit 123, and flows into the flow path 140. The second fluid, while flowing in the flow path 140, exchanges heat with the first fluid flowing through the compartment 14 of the heat exchange component 100, and flows out from the outlet 124 through the outlet conduit 125. Any suitable fluid suitable for the purpose can be cited as the second fluid. For example, in the case of a heat exchanger mounted in an automobile, the second fluid is preferably water or antifreeze (LLC as specified in JIS K 2234:2006). The temperature of the second fluid is preferably lower than the temperature of the first fluid. This is because the covered part 20 of the heat exchange component 100 does not expand at low temperatures, while the honeycomb structure 10 expands at high temperatures, thus making the fit between the two more secure.

[0065] Preferably, the outer peripheral surfaces of the covered components 20 at both ends in the flow direction of the first fluid are in a circumferential manner, closely contacting the inner surface of the outer cylinder 120. This configuration prevents leakage of the second fluid to the outside. This close contact can be achieved using any suitable means. Specific examples include welding, diffusion bonding, brazing, and mechanical fastening. Welding is preferred because it offers higher durability and reliability, and also improves structural strength.

[0066] The outer cylinder 120 is preferably made of metal. This construction results in excellent manufacturing efficiency and thermal conductivity. Examples of materials suitable for the outer cylinder include stainless steel, titanium alloy, copper alloy, aluminum alloy, and brass. Stainless steel is preferred due to its high durability, reliability, and low cost.

[0067] The thickness of the outer cylinder 120 is, for example, 0.1mm to 10mm, or, for example, 0.5mm to 5mm, or, for example, 1mm to 3mm. If the thickness of the outer cylinder is within such a range, an excellent balance is achieved between durability and reliability and cost, volume, and weight.

[0068] The outer cylinder 120 can be a one-piece molded part or a joined part formed by two or more components. If it is a joined part, it can increase the design freedom of the outer cylinder.

[0069] Example

[0070] The present invention will now be specifically described through embodiments; however, the present invention is not limited to these embodiments. The evaluation items in the embodiments are as follows.

[0071] (1) RPc, Ra and Rt

[0072] The surface roughness of the outer peripheral wall surface of the honeycomb structures fabricated in the examples and comparative examples was measured using a surface roughness measuring machine (Taylor-Hobson, product name "Form Talysurf S5K"). Measurements were performed with n=2, and the average values ​​were set as RPc, Ra, and Rt.

[0073] (2) Heat exchange test

[0074] The heat exchangers obtained in the examples and comparative examples were subjected to heat exchange tests using the following method. Air at 400°C (=Tg1) (first fluid) was circulated through the honeycomb structure at a flow rate of 10 g / s (Mg). Meanwhile, cooling water at 40°C (=Tg2) (second fluid) was supplied from the inlet at a flow rate of 10 L / min (Mw), and the cooled water after heat exchange was recovered from the outlet. After the air and cooling water had passed through the heat exchanger for exactly 5 minutes, the temperatures of the cooling water at the inlet (Tw1) and outlet (Tw2) of the heat exchanger were measured, and the heat recovery amount Q was determined. Measurements were performed with n=2, and the average value was taken as the heat recovery efficiency.

[0075] Here, the following formula represents the heat Q recovered by the cooling water.

[0076] Q(kW)=ΔTw(K)×Cpw(J / (kg·K))×Pw(kg / m3)×Mw(L / min)÷(60×10 6 )

[0077] In the formula, ΔTw=Tw2-Tw1, Cpw (specific heat of water)=4182J / (kg·K), Pw (density of water)=997kg / m³ 3 .

[0078] In addition, the heat recovery efficiency η of the heat exchanger is expressed by the following formula.

[0079] η(%)=Q / {(Tg1-Tw1)×Cpg×Mg}×100

[0080] In the formula, Cpg (specific heat of air) = 1050 J / (kg·K).

[0081] <Example 1>

[0082] 1. Fabrication of honeycomb structures

[0083] The blank containing SiC powder is extruded into the final product. Figure 3The cross-sectional shape is shown, and then it is dried and processed into the specified external dimensions to obtain a honeycomb dried body. The outer peripheral wall surface of the obtained honeycomb dried body is machined using a machining center. The grinding stone of the machining center has a grit size of 90, a diameter of 20 mm, a rotation speed of 3000 rpm, a peripheral speed of 3.1 m / s, and a depth of cut of 0.2 mm. The honeycomb molded body with the machined outer peripheral wall surface is then subjected to Si impregnation sintering to produce a cylindrical honeycomb structure. The obtained honeycomb structure has an RPc of 55.4 pks / cm, a Ra of 9.12 μm, and a Rt of 73.5 μm on the outer peripheral wall surface. It should be noted that the honeycomb structure is so-called donut-shaped, i.e., the diameter of the outer peripheral wall is 75 mm, the diameter of the inner peripheral wall is 57 mm, and the length in the direction of cell extension is 33 mm. Figure 3 The honeycomb structure shown has a hollow region at the center of its cross-section orthogonal to the axial direction (the direction of cell extension). The cells in the cross-section orthogonal to the axial direction (the direction of cell extension) of the honeycomb structure are quadrilateral in shape. The cell density of the honeycomb structure is 57 cells / cm³. 2 The thickness of the partition wall is 0.3 mm, and the thickness of the outer and inner peripheral walls is 1.5 mm.

[0084] 2. Fabrication of heat exchange components

[0085] A stainless steel tubular component was used as the coating. The honeycomb structure obtained above was inserted into the center of the heated and expanded tubular component, and then cooled and contracted. This process, through thermo-pressuring, fixed the honeycomb structure within the coating component, causes the inner circumferential surface of the coating component to fit into the outer circumferential surface of the honeycomb structure, thus creating a heat exchange component. The RPc of the inner circumferential surface of the coating component is 130 pks / cm.

[0086] 3. Fabrication of heat exchangers

[0087] The product is formed by molding. Figure 4 The illustrated cylindrical shell (outer cylinder) is made of stainless steel and includes a cylindrical section, an inlet, an inlet conduit connecting the inlet and the cylindrical section, an outlet, and an outlet conduit connecting the outlet and the cylindrical section. The heat exchange component obtained above is inserted into the outer cylinder, and the heat exchange component is fixed to the outer cylinder by welding, thus completely surrounding the heat exchange component. The outer peripheral surfaces at the two ends of the honeycomb structure along the axial direction (direction of compartment extension) are welded to be tightly connected to the inner surface of the outer cylinder in a surrounding manner. Thus, a heat exchanger is manufactured. The obtained heat exchanger is evaluated as described in (2) above. The results are shown in Table 1.

[0088] <Examples 2-4 and Comparative Examples 1-2>

[0089] The outer peripheral wall surface of the honeycomb molded body was machined under the conditions shown in Table 1. Otherwise, a honeycomb structure with RPc, Ra, and Rt as shown in Table 1 was fabricated, similar to Example 1. A heat exchange component and heat exchanger were fabricated using this honeycomb structure, similar to Example 1. The resulting heat exchanger was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0090] <Example 5>

[0091] Using a cylindrical grinding disc instead of a machining center, the outer peripheral wall surface of the honeycomb drying body was machined under the conditions shown in Table 1. During machining, the honeycomb drying body was rotated at 300 rpm. Otherwise, a honeycomb structure with RPc, Ra, and Rt as shown in Table 1 was fabricated on the outer peripheral wall surface, similar to Example 1. A heat exchange component and heat exchanger were fabricated using this honeycomb structure, similar to Example 1. The resulting heat exchanger was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0092] <Example 6>

[0093] The blank containing SiC powder was extruded into the same shape as in Example 1, then dried, processed to the specified dimensions, and then subjected to Si impregnation sintering to obtain a honeycomb sintered body. The outer peripheral wall surface of the obtained honeycomb sintered body was machined using a cylindrical grinding wheel. The grinding wheel had a grit size of 170, a diameter of 350 mm, a rotation speed of 1800 rpm, a peripheral speed of 33 m / s, and a depth of cut of 0.2 mm. Furthermore, the honeycomb sintered body was rotated at 150 rpm during machining. The resulting honeycomb structure had an RPc of 91.4 pks / cm, a Ra of 1.53 μm, and a Rt of 32.7 μm on the outer peripheral wall surface. A cylindrical honeycomb structure was thus produced. The dimensions and shape of the obtained honeycomb structure were the same as in Example 1. In addition to using this honeycomb structure, a heat exchange component and a heat exchanger were manufactured in the same manner as in Example 1. The obtained heat exchanger was evaluated in the same way as in Example 1. The results are shown in Table 1.

[0094] Table 1

[0095]

[0096] As shown in Table 1, the heat recovery efficiency of the heat exchanger in the embodiment of the present invention is significantly increased compared with that of the comparative example.

[0097] Industrial availability

[0098] The heat exchange components and heat exchangers of the embodiments of the present invention are used for any suitable application of heat exchange between a heating element (high temperature side) and a heated element (low temperature side), and in particular, they can be preferentially used for heat recovery from automobile exhaust.

[0099] Symbol Explanation

[0100] 10. Honeycomb structure

[0101] 12a First end face

[0102] 12b Second end face

[0103] 14 compartments

[0104] 16 Next door

[0105] 17. Inner peripheral wall

[0106] 18. Outer wall

[0107] 20 Covered parts

[0108] 100 Heat exchange components

[0109] 120 outer cylinder

[0110] 140 Second fluid flow path

[0111] 200 heat exchanger

Claims

1. A heat exchange component, wherein, have: A honeycomb structure having partitions and an outer peripheral wall, the partitions defining compartments that extend from a first end face to a second end face to form a flow path for a first fluid; as well as The covered component covers the outer peripheral wall of the honeycomb structure. The partition wall and the outer peripheral wall contain ceramic as the main component. The surface RPc of the outer peripheral wall, as specified in JIS B 0601:2013, is 55 pks / cm or higher. The maximum cross-sectional height Rt of the surface of the outer peripheral wall, as specified in JIS B 0601:2013, is less than 75 μm.

2. The heat exchange component according to claim 1, wherein, The RPc of the inner circumferential surface of the covered component is 45 pks / cm or more.

3. The heat exchange component according to claim 1 or 2, wherein, The partition wall and the outer peripheral wall are made of ceramic containing silicon carbide as the main component.

4. The heat exchange component according to claim 1 or 2, wherein, The honeycomb structure has the compartments across its entire cross-section in a direction perpendicular to the flow path of the first fluid.

5. The heat exchange component according to claim 1 or 2, wherein, The honeycomb structure has a hollow region at the center of its cross-section in a direction perpendicular to the flow path of the first fluid.

6. A heat exchanger, wherein, have: The heat exchange component according to any one of claims 1 to 5; and The outer cylinder is separately disposed on the outside of the heat exchange component. A flow path for a second fluid is formed between the outer cylinder and the covered component of the heat exchange component.

7. A method for manufacturing a heat exchange component according to any one of claims 1 to 5, wherein, include: The outer peripheral wall surface is machined using a grinding stone with a grit size of 90 or higher and a diameter of 20 mm or higher at a circumferential speed of 3.0 m / s or higher.

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