heat exchanger

Abstract

To provide a heat exchanger capable of suppressing the erosion of a member constituting a flow path for second fluid while improving heat recovery performance.SOLUTION: A heat exchanger 100 includes: a heat recovery member 1 where first fluid can flow through; an inner cylinder 10 housing the heat recovery member 1; an outer cylinder 20 that includes a supply port 21 allowing the second fluid to be supplied and a discharge port 22 allowing the second fluid to be discharged, and that is arranged at a space radially outside the inner cylinder 10 so as to form a flow path 60 for the second fluid between the inner cylinder 10 and itself; a supply pipe 30 connected to the supply port 21; and a discharge pipe 40 connected to the discharge port 22. The heat recovery member 1 is arranged so that, with reference to a flow path direction of the first fluid, an axial center part C1 of the heat recovery member 1 is on the downstream side of an axial center part C2 of the inner cylinder 10 and a downstream side end 2 of the heat recovery member 1 is on the upstream side of a downstream side end 61b of the flow path 60 for the second fluid.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a heat exchanger. [Background technology]

[0002] In recent years, there has been a demand for improved fuel economy in automobiles. In particular, to prevent a decline in fuel economy when the engine is cold, such as when starting the engine, there are hopes for systems that can quickly warm the coolant, engine oil, automatic transmission fluid (ATF), etc., thereby reducing friction loss. There are also hopes for systems that can heat exhaust gas purification catalysts to quickly activate them.

[0003] 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 the heat exchanger and a second fluid outside the heat exchanger. Such a heat exchanger can effectively utilize heat by exchanging heat from a high-temperature fluid (e.g., exhaust gas) to a low-temperature fluid (e.g., cooling water).

[0004] A heat exchanger for recovering heat from high-temperature gas such as automobile exhaust gas includes a hollow columnar honeycomb structure having an inner peripheral wall, an outer peripheral wall, and partition walls disposed between the inner and outer peripheral walls to define a plurality of cells that serve as a flow path for a first fluid extending from a first end face to a second end face; a first outer cylindrical member fitted onto the surface of the outer peripheral wall of the columnar honeycomb structure; an inner cylindrical member fitted onto the surface of the inner peripheral wall of the columnar honeycomb structure; and an upstream cylindrical member having portions arranged at intervals on the radially inner side of the inner cylindrical member to form a flow path for the first fluid. A known heat exchanger includes a first outer cylindrical member, a cylindrical connecting member that connects the upstream end of the first outer cylindrical member to the upstream side of the upstream cylindrical member to form a flow path for a first fluid, a downstream cylindrical member that is connected to the downstream end of the first outer cylindrical member and has a portion that is spaced apart radially outside the inner cylindrical member to form a flow path for the first fluid, a second outer cylindrical member that is spaced apart radially outside the first outer cylindrical member to form a flow path for a second fluid, and an on-off valve that is located on the downstream end of the inner cylindrical member (Patent Document 1).A heat exchanger with such a structure can switch between promoting heat recovery from the first fluid to the second fluid and suppressing the heat recovery by opening and closing the on-off valve. In addition, in this heat exchanger, the tubular member has a tapered portion that narrows in diameter from the position of the second end face of the columnar honeycomb structure toward the downstream end, and by controlling the ratio of the difference between the inner diameter of the downstream end of the inner tubular member and the inner diameter of the downstream end of the upstream tubular member to be within ±20%, or by extending the downstream end of the upstream tubular member downstream of the position of the second end face of the columnar honeycomb structure, the backflow phenomenon of the first fluid can be suppressed when heat recovery is suppressed, resulting in good heat insulation performance. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2021 / 171668 Summary of the Invention [Problem to be solved by the invention]

[0006] The heat exchanger of Patent Document 1 does not particularly focus on the flow path for the second fluid formed between the first outer cylindrical member and the second outer cylindrical member. In the course of continuing research to improve the heat recovery performance of a heat exchanger, the inventors have discovered that there are regions in the second fluid flow path where the second fluid stagnates, and that boiling of the second fluid stagnates in these regions reduces the heat recovery performance. They have also discovered that when the stagnant second fluid boils, the surrounding components constituting the second fluid flow path are more likely to melt.

[0007] The present invention has been made to solve the above-mentioned problems, and aims to provide a heat exchanger that can improve heat recovery performance and suppress melting damage to components that form the flow path of the second fluid by suppressing boiling of the second fluid. [Means for solving the problem]

[0008] As a result of extensive research into heat exchangers of various structures, the inventors discovered that the above problems could be solved by controlling the position of the heat recovery member, leading to the completion of the present invention.

[0009] That is, the present invention provides a heat recovery member through which a first fluid can flow, an inner cylinder that accommodates the heat recovery member; an outer cylinder having a supply port capable of supplying a second fluid and a discharge port capable of discharging the second fluid, the outer cylinder being disposed radially outside the inner cylinder at a distance so as to form a flow path for the second fluid between the outer cylinder and the inner cylinder; a supply pipe connected to the supply port; a discharge pipe connected to the discharge port; Equipped with When a flow path direction of the first fluid is used as a reference, the supply port of the outer cylinder is located downstream of a center of the outer cylinder in an axial direction, and the discharge port of the outer cylinder is located upstream of the center of the outer cylinder in an axial direction, When the flow direction of the first fluid is used as a reference, the axial center of the heat recovery member is Second fluid flow path the heat recovery member is disposed downstream of the axial center of the second fluid, and the downstream end of the heat recovery member is disposed upstream of the downstream end of the flow path of the second fluid. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a heat exchanger that can improve heat recovery performance and suppress melting damage to members that form the flow path of the second fluid. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view parallel to the flow direction of a first fluid of a heat exchanger according to a first embodiment of the present invention. [Figure 2] 2 is a cross-sectional view of the heat exchanger of FIG. 1 taken along line aa'. [Figure 3] 1 is a cross-sectional view perpendicular to the axial direction of a honeycomb structure that can be used as a heat recovery member. [Figure 4] 1 is a cross-sectional view perpendicular to the axial direction of a honeycomb structure that can be used as a heat recovery member. [Figure 5] FIG. 5 is a cross-sectional view parallel to the flow direction of a first fluid of a heat exchanger according to a second embodiment of the present invention. [Figure 6] 6 is a cross-sectional view of the heat exchanger of FIG. 5 taken along the line bb'. [Figure 7] FIG. 4 is an enlarged cross-sectional view of the periphery of one end of a flow path for a second fluid. [Figure 8] FIG. 4 is an enlarged cross-sectional view of the periphery of one end of a flow path for a second fluid. [Figure 9] FIG. 10 is a cross-sectional view parallel to the flow direction of a first fluid of a heat exchanger body according to a third embodiment of the present invention. [Figure 10] FIG. 10 is a cross-sectional view parallel to the flow direction of the first fluid of another heat exchanger according to the third embodiment of the present invention. [Figure 11] FIG. 10 is a cross-sectional view parallel to the flow direction of the first fluid of a heat exchanger according to a fourth embodiment of the present invention. [Figure 12] FIG. 10 is a cross-sectional view parallel to the flow direction of the first fluid of a heat exchanger according to a fifth embodiment of the present invention. [Figure 13] FIG. 10 is a cross-sectional view parallel to the flow direction of the first fluid of a heat exchanger according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention relates to a heat exchanger including a heat recovery element through which a first fluid can flow, an inner cylinder accommodating the heat recovery element, an outer cylinder having a supply port through which a second fluid can be supplied and an outlet port through which the second fluid can be discharged and disposed radially outside the inner cylinder at a distance to define a flow path for the second fluid between the inner cylinder and the outer cylinder, a supply pipe connected to the supply port, and an outlet pipe connected to the outlet port, the heat recovery element being disposed such that, based on the flow path direction of the first fluid, the axial center of the heat recovery element is downstream of the axial center of the inner cylinder and the downstream end of the heat recovery element is upstream of the downstream end of the flow path for the second fluid. The heat exchanger may also include a boiling suppression part in the flow path for the second fluid to suppress boiling of the second fluid.

[0013] Hereinafter, embodiments of the heat exchanger of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments, and it should be understood that modifications and improvements made to the following embodiments based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention are also within the scope of the present invention.

[0014] (Embodiment 1) Fig. 1 is a cross-sectional view parallel to the flow direction of a first fluid of a heat exchanger according to a first embodiment of the present invention, and Fig. 2 is a cross-sectional view taken along line aa' of the heat exchanger of Fig. 1. As shown in FIGS. 1 and 2, a heat exchanger 100 according to the first embodiment of the present invention includes a heat recovery member 1, an inner cylinder 10, an outer cylinder 20, a supply pipe 30, and a discharge pipe 40.

[0015] <Heat recovery component 1> The heat recovery member 1 is a member through which the first fluid can flow. The heat recovery member 1 has a function of recovering heat from the first fluid when the first fluid flows through it. The heat recovery member 1 is housed inside the inner cylinder 10. Depending on the shape of the flow path 60 for the second fluid, the flow of the second fluid may slow down around the axial end of the flow path 60 for the second fluid (particularly, around the upstream end 61a of the flow path 60 for the second fluid when the flow path direction of the first fluid is used as the reference). In this case, stagnation of the second fluid is likely to occur around the axial end of the flow path 60 for the second fluid, and the temperature of the second fluid may continuously rise and the second fluid may boil. In this state, the heat recovery performance decreases and the surrounding components (the inner cylinder 10 and the outer cylinder 20) are more likely to melt. Therefore, the heat recovery member 1 is disposed such that, based on the flow path direction of the first fluid, the axial center C1 of the heat recovery member 1 is downstream of the axial center C2 of the inner cylinder 10, and the downstream end 2 of the heat recovery member 1 is upstream of the downstream end 61b of the flow path 60 of the second fluid. By disposing the heat recovery member 1 in this position, the flow path of the first fluid before entering the heat recovery member 1 is widened. As a result, the flow velocity of the first fluid decreases in this portion, and the heat transfer coefficient decreases, thereby suppressing the transfer of heat from the first fluid to the second flow path via the inner cylinder 10. Furthermore, the distance between the upstream end 61a of the flow path 60 of the second fluid and the heat recovery member 1 is also long, thereby suppressing heat input by the heat recovery member 1 around the upstream end 61a of the flow path 60 of the second fluid, and thereby lowering the temperature of the second fluid. As a result, boiling of the second fluid around the upstream end 61a of the flow path 60 of the second fluid is suppressed.

[0016] When the flow path direction of the first fluid is used as a reference, the downstream end 2 of the heat recovery member 1 is preferably disposed upstream, at a distance of 10 mm or more from the downstream end 61b of the flow path 60 of the second fluid. By disposing the downstream end 2 of the heat recovery member 1 at such a position, the above-mentioned effects can be stably enhanced.

[0017] When the flow path direction of the first fluid is used as a reference, the downstream end 2 of the heat recovery member 1 is preferably disposed upstream from the downstream end 61b of the flow path 60 of the second fluid by 10% or more of the length of the flow path 60 of the second fluid. By disposing the downstream end 2 of the heat recovery member 1 at such a position, the above-mentioned effects can be stably enhanced.

[0018] When the flow path direction of the first fluid is used as a reference, the length (axial length) of the heat recovery member 1 is preferably 20 to 90% of the length of the flow path 60 of the second fluid. By controlling the length of the heat recovery member 1 to such a value, the above-mentioned effects can be stably enhanced.

[0019] The heat recovery member 1 is not particularly limited, but is preferably a honeycomb structure. 3 and 4 show cross-sectional views perpendicular to the axial direction (flow path direction of the first fluid) of a honeycomb structure that can be used as the heat recovery member 1. FIG. A honeycomb structure 1000 shown in Fig. 3 has an outer peripheral wall 1100 and a plurality of partition walls 1300 disposed inside the outer peripheral wall 1100, extending from a first end face to a second end face to define a plurality of cells 1200 that serve as flow paths for a first fluid. A honeycomb structure 2000 shown in Fig. 4 has an outer peripheral wall 1100, an inner peripheral wall 1400, and partition walls 1300 disposed between the outer peripheral wall 1100 and the inner peripheral wall 1400, extending from the first end face to the second end face to define a plurality of cells 1200 that serve as flow paths for the first fluid.

[0020] The shape (external shape) of the honeycomb structures 1000 and 2000 is not particularly limited and may be appropriately set depending on the shape of the inner tube 10. Examples of the shape (external shape) of the honeycomb structures 1000 and 2000 include a circular cylinder, an elliptical cylinder, a square cylinder, or other polygonal cylinders. The shape of the hollow portion (the inner region of the inner peripheral wall 1400) of the honeycomb structure 2000 is not particularly limited and may be the same as or different from the external shape of the honeycomb structure 2000, but is preferably the same as the external shape from the viewpoint of resistance to external impacts, thermal stress, etc.

[0021] The thickness of outer peripheral wall 1100 and inner peripheral wall 1400 is preferably greater than the thickness of partition wall 1300. This configuration can increase the strength of outer peripheral wall 1100 and inner peripheral wall 1400, which are prone to damage (e.g., cracks, fractures, etc.) due to external impacts, thermal stress caused by the temperature difference between the first fluid and the second fluid, and the like. The thicknesses of the outer peripheral wall 1100, the partition walls 1300, and the inner peripheral wall 1400 can be adjusted appropriately depending on the application. For example, when the heat exchanger 100 is used for general heat exchange applications, the thicknesses of the outer peripheral wall 1100 and the inner peripheral wall 1400 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. Furthermore, when the heat exchanger 100 is used for heat storage applications, it is also preferable that the thickness of the outer peripheral wall 1100 be 10 mm or more to increase the heat capacity of the outer peripheral wall 1100. The thickness of the partition walls 1300 is preferably 0.1 to 1 mm, and more preferably 0.2 to 0.6 mm. By making the thickness of the partition walls 1300 0.1 mm or more, it is possible to ensure sufficient mechanical strength of the honeycomb structures 1000 and 2000. Furthermore, by making the thickness of the partition walls 1300 1 mm or less, it is possible to suppress problems such as increased pressure loss due to a decrease in the opening area and decreased heat recovery efficiency due to a decrease in the contact area with the first fluid.

[0022] The outer peripheral wall 1100, the partition wall 1300, and the inner peripheral wall 1400 are mainly composed of ceramics. "Mainly composed of ceramics" means that the mass ratio of ceramics to the total mass is 50 mass % or more.

[0023] The porosity of the outer peripheral wall 1100, the partition walls 1300, and the inner peripheral wall 1400 is preferably 10% or less, more preferably 5% or less, and particularly preferably 3% or less. These porosities can also be 0%. By setting these porosities to 10% or less, the thermal conductivity can be improved.

[0024] The outer peripheral wall 1100, the partition wall 1300, and the inner peripheral wall 1400 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 is 50 mass% or more.

[0025] More specifically, Si-impregnated SiC, (Si+Al)-impregnated SiC, metal composite SiC, recrystallized SiC, SiN, SiC, and the like can be used as materials for the outer peripheral wall 1100, the partition wall 1300, and the inner peripheral wall 1400. 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.

[0026] The cell density (i.e., the number of cells 1200 per unit area) in the cross section of the honeycomb structures 1000 and 2000 perpendicular to the flow path direction of the first fluid is not particularly limited and may be adjusted appropriately depending on the application, etc., but is preferably 4 to 320 cells / cm. 2 The cell density is preferably in the range of 4 cells / cm. 2 By setting the cell density to the above, it is possible to sufficiently secure the strength of the partition walls 1300, and in turn the strength and effective GSA (geometric surface area) of the honeycomb structures 1000 and 2000 themselves. 2 By setting the above, it is possible to prevent an increase in pressure loss when the first fluid flows.

[0027] The isostatic strength of the honeycomb structures 1000 and 2000 is preferably more than 100 MPa, more preferably 150 MPa or more, and even more preferably 200 MPa or more. When the isostatic strength of the honeycomb structures 1000 and 2000 exceeds 100 MPa, the honeycomb structures 1000 and 2000 have excellent durability. The isostatic strength of the honeycomb structures 1000 and 2000 can be measured in accordance with the method for measuring isostatic fracture strength specified in JASO standard M505-87, an automotive standard issued by the Society of Automotive Engineers of Japan.

[0028] The diameter (outer diameter) of the outer peripheral wall 1100 in a cross section perpendicular to the flow path direction of the first fluid is preferably 20 to 200 mm, more preferably 30 to 100 mm. By setting the diameter in this range, it is possible to improve the heat recovery efficiency. When the outer peripheral wall 1100 is not circular, the diameter of the outer peripheral wall 1100 is defined as the diameter of the largest circle inscribed in the cross-sectional shape of the outer peripheral wall 1100. In the honeycomb structure 2000, the diameter of the inner peripheral wall 1400 in a cross section perpendicular to the flow path direction of the first fluid is preferably 1 to 60 mm, more preferably 2 to 30 mm. When the cross section of the inner peripheral wall 1400 is not circular, the diameter of the inner peripheral wall 1400 is defined as the diameter of the largest circle inscribed in the cross section of the inner peripheral wall 1400.

[0029] The thermal conductivity of the honeycomb structures 1000 and 2000 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 structures 1000 and 2000 within this range, the thermal conductivity is improved, and heat within the honeycomb structures 1000 and 2000 can be efficiently transferred to the outside. The thermal conductivity values ​​are measured by a laser flash method (JIS R1611-1997).

[0030] When exhaust gas is flowed as the first fluid through the cells 1200 of the honeycomb structure 1000 or 2000, a catalyst may be supported on the partition walls 1300 of the honeycomb structure 1000 or 2000. Supporting a catalyst on the partition walls 1300 makes it possible to convert CO, NOx, HC, and other substances 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.

[0031] <Inner cylinder 10> The inner cylinder 10 is a member that houses the heat recovery member 1. The inner cylinder 10 is fitted onto the outer circumferential surface of the heat recovery member 1 that is parallel to the flow direction of the first fluid. Here, in this specification, "fitting" means that the heat recovery member 1 and the inner cylinder 10 are fixed in a fitted state with each other. Therefore, the fitting of the heat recovery member 1 and the inner cylinder 10 includes fixing methods using fitting such as clearance fitting, interference fitting, and shrink fitting, as well as cases where the heat recovery member 1 and the inner cylinder 10 are fixed to each other by brazing, welding, diffusion bonding, etc.

[0032] The shape of the inner cylinder 10 is not particularly limited, and may be any of various tubular shapes such as a cylindrical shape or a rectangular cylindrical shape. The axial direction of the inner cylinder 10 preferably coincides with the axial direction of the heat recovery member 1, and the central axis of the inner cylinder 10 preferably coincides with the central axis of the heat recovery member 1. The diameter (outer diameter and inner diameter) of the inner cylinder 10 may be uniform along the axial direction, but at least a part of it (for example, both ends in the axial direction) may be reduced or increased in diameter. When the inner cylinder 10 is not cylindrical, the outer diameter and inner diameter of the inner cylinder 10 refer to the diameters of the largest circles circumscribing and inscribing the cross-sectional shape of the inner cylinder 10 perpendicular to the flow direction of the first fluid.

[0033] The inner cylinder 10 preferably has an inner peripheral surface shape that corresponds to the outer peripheral surface of the heat recovery member 1 that is parallel to the flow direction of the first fluid. When the inner peripheral surface of the inner cylinder 10 directly contacts the outer peripheral surface of the heat recovery member 1 that is parallel to the flow direction of the first fluid, thermal conductivity is improved, and heat in the heat recovery member 1 can be efficiently transferred to the inner cylinder 10.

[0034] From the viewpoint of increasing the heat recovery efficiency, it is preferable that the ratio of the area of ​​the portion of the outer peripheral surface of the heat recovery member 1 parallel to the flow direction of the first fluid that is circumferentially covered by the inner tube 10 to the total area of ​​the outer peripheral surface of the heat recovery member 1 parallel to the flow direction of the first fluid is high. Specifically, this 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 heat recovery member 1 parallel to the flow direction of the first fluid is circumferentially covered by the inner tube 10).

[0035] The material of the inner cylinder 10 is not particularly limited, but is preferably a metal from the viewpoint of manufacturability. Furthermore, if the inner cylinder 10 is made of a metal, it is advantageous in that it can be easily welded to the outer cylinder 20 and the like. For example, stainless steel, titanium alloy, copper alloy, aluminum alloy, brass, etc. can be used as the material of the inner cylinder 10. Among these, stainless steel is preferred because it is highly durable, reliable, and inexpensive.

[0036] The thickness of the inner cylinder 10 is not particularly limited, but is preferably 0.1 mm or more, more preferably 0.3 mm or more, and even more preferably 0.5 mm or more. By making the thickness of the inner cylinder 10 0.1 mm or more, durability and reliability can be ensured. Furthermore, the thickness of the inner cylinder 10 is preferably 10 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less. By making the thickness of the inner cylinder 10 10 mm or less, thermal resistance can be reduced and thermal conductivity can be increased.

[0037] <Outer cylinder 20> The outer cylinder 20 has a supply port 21 through which the second fluid can be supplied and a discharge port 22 through which the second fluid can be discharged. The outer cylinder 20 is disposed radially outside the inner cylinder 10 at a distance so as to form a flow path 60 for the second fluid between the outer cylinder 20 and the inner cylinder 10. It is preferable that the axial direction of the outer cylinder 20 coincides with the axial direction of the inner cylinder 10 , and that the central axis of the outer cylinder 20 coincides with the central axis of the inner cylinder 10 .

[0038] It is preferable that the outer cylinder 20 is arranged so that the inner surfaces of the upstream end and downstream end are in direct or indirect contact with the outer surface of the inner cylinder 10, based on the flow direction of the first fluid. The method for fixing the inner peripheral surface of the upstream end and downstream end of the outer tube 20 to the outer peripheral surface of the inner tube 10 is not particularly limited, but may include fixing methods using fitting such as clearance fitting, interference fitting, and shrink fitting, as well as brazing, welding, diffusion bonding, etc.

[0039] The shape of the outer cylinder 20 is not particularly limited, and may be any of various tubular shapes such as a cylindrical shape or a rectangular cylindrical shape. The diameters (outer diameter and inner diameter) of the outer cylinder 20 may be uniform along the axial direction, but may be reduced or increased in at least a portion (for example, the axial center portion, both axial ends, etc.). For example, by reducing the diameter of the axial center portion of the outer cylinder 20, the second fluid can be distributed throughout the entire outer periphery of the inner cylinder 10 on the supply port 21 and discharge port 22 sides of the outer cylinder 20. Therefore, the amount of the second fluid that does not contribute to heat exchange in the axial center portion is reduced, thereby improving heat exchange efficiency. When the outer cylinder 20 is not cylindrical, the outer diameter and inner diameter of the outer cylinder 20 refer to the diameters of the largest circles circumscribing and inscribing the cross-sectional shape of the outer cylinder 20 perpendicular to the flow direction of the first fluid.

[0040] The material of the outer cylinder 20 is not particularly limited, and the same material as that of the inner cylinder 10 described above can be used. The thickness of the outer cylinder 20 is not particularly limited, and can be the same as that of the inner cylinder 10 described above.

[0041] <Supply Pipe 30 and Discharge Pipe 40> The supply pipe 30 is connected to the supply port 21 of the outer cylinder 20, and the discharge pipe 40 is connected to the discharge port 22 of the outer cylinder 20. By connecting the supply pipe 30 and the discharge pipe 40 in this manner, the second fluid can be supplied and discharged between the inner cylinder 10 and the outer cylinder 20. The supply pipe 30 and the discharge pipe 40 may extend in the same direction or in different directions.

[0042] In the heat exchanger 100 according to the first embodiment of the present invention, the heat recovery member 1 is positioned such that, when the flow path direction of the first fluid is used as a reference, the axial center C1 of the heat recovery member 1 is downstream of the axial center C2 of the inner tube 10, and the downstream end 2 of the heat recovery member 1 is upstream of the downstream end 61b of the flow path 60 of the second fluid. This improves heat recovery performance and suppresses melting damage to the members that make up the flow path 60 of the second fluid.

[0043] (Embodiment 2) The heat exchanger according to the second embodiment of the present invention differs from the heat exchanger 100 according to the first embodiment of the present invention in that a flow path closing member 50 is provided as a boiling suppression part in the flow path of the second fluid. Fig. 5 is a cross-sectional view parallel to the flow direction of the first fluid of the heat exchanger according to the second embodiment of the present invention. Fig. 6 is a cross-sectional view taken along the line b-b' of the heat exchanger of Fig. 5. Fig. 5 shows an example in which a hollow honeycomb structure 2000 is used as the heat recovery member 1. 5 and 6, a heat exchanger 200 according to a second embodiment of the present invention includes an inner cylinder 10, an outer cylinder 20, a supply pipe 30, a discharge pipe 40, and a flow path blocking member 50 serving as a boiling suppression unit. The heat exchanger 200 according to the second embodiment of the present invention further includes a first cylindrical member 210, a second cylindrical member 220, a first cylindrical connecting member 230, a second cylindrical connecting member 240, a third cylindrical member 250, and an on-off valve 260. In addition, components having the same symbols as those appearing in the description of the heat exchanger 100 according to embodiment 1 of the present invention are the same as the components of the heat exchanger 200 according to embodiment 2 of the present invention, and therefore their description will be omitted.

[0044] <Flow path closing member 50> The flow path closing member 50 is a boiling suppression portion that suppresses boiling of the second fluid. The flow path closing member 50 is arranged so as to close at least a part of the flow path 60 for the second fluid. As described in the first embodiment, depending on the shape of the second fluid flow path 60, the flow of the second fluid may slow down around the axial end of the second fluid flow path 60. In this case, stagnation of the second fluid is likely to occur around the axial end of the second fluid flow path 60, and the temperature of the second fluid may continuously rise and boil. In this state, the heat recovery performance decreases and the surrounding components (the inner cylinder 10 and the outer cylinder 20) are likely to melt. The flow path closing member 50 is disposed in a portion where the second fluid is likely to stagnate and boil as described above. Therefore, the flow path closing member 50 is preferably disposed so as to close at least one end of the flow path 60 for the second fluid, and more preferably disposed so as to close both ends of the flow path 60 for the second fluid.

[0045] FIG. 7 shows an enlarged cross-sectional view of the vicinity of one end of the flow path 60 for the second fluid. When the flow path closing member 50 is disposed at the end of the flow path 60 for the second fluid, it is preferable to close a length region L from the flow path end E for the second fluid to 50% or less of the maximum flow path height H of the flow path 60 for the second fluid. By closing such a region with the flow path closing member 50, the second fluid is less likely to stagnate, and boiling of the second fluid can be stably suppressed. If a length region from the flow path end E for the second fluid to more than 50% of the maximum flow path height H of the flow path 60 for the second fluid is closed, the flow path 60 for the second fluid is reduced too much, which may result in a decrease in heat recovery performance.

[0046] The flow path closing member 50 is preferably a ring-shaped member. By using a ring-shaped member for the flow path closing member 50, the flow path closing member 50 can be easily arranged at a predetermined position within the flow path 60 for the second fluid. The ring-shaped member may be formed, for example, by placing two halves of a member at predetermined positions within the flow path 60 for the second fluid to form a single ring, and then fixing the two halves together by welding or adhesive.

[0047] The shape of the flow path closing member 50 is not particularly limited as long as it is a shape that can close a predetermined area. For example, in a cross section parallel to the flow direction of the first fluid, the shape of the flow path closing member 50 can be exemplified as a sector (upper left figure), a trapezoid (upper right figure), a chamfered shape (lower left figure), an irregular shape (lower right figure), etc. as shown in Fig. 8, in addition to the triangle shown in Figs. 5 and 7. Note that Fig. 8, like Fig. 7, is an enlarged cross-sectional view of the periphery of one end of a flow path 60 for the second fluid.

[0048] The material of the flow path closing member 50 is not particularly limited as long as it is a material that does not dissolve in the second fluid and has a melting point higher than the boiling point of the second fluid. For example, if the second fluid is water, the material of the flow path closing member 50 may be a water-insoluble material with a melting point higher than 100°C. Examples of materials that can be used for the flow path closing member 50 include metals and thermosetting resins, specifically stainless steel, titanium alloys, copper alloys, aluminum alloys, brass, phenolic resins, urea resins, melamine resins, epoxy resins, unsaturated polyester resins, alkyd resins, polyimide resins, polyurethane resins, allyl resins, diallyl phthalate resins, and silicone resins.

[0049] <First cylindrical member 210> The first cylindrical member 210 is fitted into the inner peripheral wall 1400 of the honeycomb structure 2000. The fitting method is not particularly limited, and the same fitting method as above can be used. The first cylindrical member 210 is a cylindrical member having an upstream end and a downstream end, and a part of its outer peripheral surface is fitted into the inner peripheral wall 1400 of the honeycomb structure 2000. The part of the outer peripheral surface of the first cylindrical member 210 and the inner peripheral wall 1400 of the honeycomb structure 2000 may be in direct contact with each other, or may be indirectly in contact with each other via a sealing material 270 (for example, a mat material, a mesh material, a ring member, or the like).

[0050] It is preferable that the axial direction of the first cylindrical member 210 coincides with the axial direction of the honeycomb structure 2000 , and the central axis of the first cylindrical member 210 coincides with the central axis of the honeycomb structure 2000 . The material of the first cylindrical member 210 is not particularly limited, and the same material as that of the inner cylinder 10 described above can be used. The thickness of the first cylindrical member 210 is not particularly limited, and can be the same as that of the inner cylinder 10 described above.

[0051] The first cylindrical member 210 may have a tapered portion whose diameter decreases from a position corresponding to the second end face of the honeycomb structure 2000 toward the downstream end. By providing such a tapered portion, it is possible to reduce the difference in inner diameter between the downstream end of the first cylindrical member 210 and the downstream end of the second cylindrical member 220. In this case, during heat recovery suppression (when the on-off valve 260 is open), the flow velocity of the first fluid near the downstream end of the second cylindrical member 220 can be made approximately the same as the flow velocity of the first fluid near the downstream end of the first cylindrical member 210, thereby reducing the pressure difference between the downstream end of the second cylindrical member 220 and the downstream end of the first cylindrical member 210. As a result, when heat recovery is suppressed, the backflow phenomenon of the first fluid flowing through the gap between the first cylindrical member 210 and the second cylindrical member 220 into the honeycomb structure 2000 can be suppressed, thereby improving heat insulation performance.

[0052] <Second cylindrical member 220> The second cylindrical member 220 has a portion that is arranged radially inward of the first cylindrical member 210 at a distance so as to form a flow path for the first fluid. The second cylindrical member 220 is a cylindrical member having an upstream end and a downstream end. It is preferable that the axial direction of the second cylindrical member 220 coincides with the axial direction of the honeycomb structure 2000 , and the central axis of the second cylindrical member 220 coincides with the central axis of the honeycomb structure 2000 .

[0053] The structure of the upstream end of the second cylindrical member 220 is not particularly limited, and can be adjusted appropriately depending on the shape of another component (such as a pipe) to which the upstream end of the second cylindrical member 220 is connected. For example, if the diameter of the other component is larger than the diameter of the upstream end, the diameter of the upstream end can be increased.

[0054] The method for fixing the second cylindrical member 220 is not particularly limited, but for example, it may be fixed to the inner tube 10 via the first cylindrical connecting member 230 described below. The fixing method is not particularly limited, and may be the same as the method for fixing the inner tube 10 described above.

[0055] The material of the second cylindrical member 220 is not particularly limited, and the same material as that of the inner cylinder 10 described above can be used. The thickness of the second cylindrical member 220 is not particularly limited, and can be the same as that of the inner cylinder 10 described above.

[0056] <First tubular connecting member 230> The first tubular connecting member 230 is a tubular member that connects the upstream end of the inner cylinder 10 and the upstream side of the second tubular member 220 so as to form a flow path for the first fluid. The connection may be either direct or indirect. In the case of an indirect connection, for example, the upstream end of the outer cylinder 20 may be disposed between the upstream end of the inner cylinder 10 and the upstream side of the second tubular member 220.

[0057] It is preferable that the axial direction of the first cylindrical connecting member 230 coincides with the axial direction of the honeycomb structure 2000 , and the central axis of the first cylindrical connecting member 230 coincides with the central axis of the honeycomb structure 2000 .

[0058] The material of the first cylindrical connecting member 230 is not particularly limited, and the same material as that of the inner cylinder 10 described above can be used. The thickness of the first cylindrical connecting member 230 is not particularly limited, and can be the same as that of the inner cylinder 10 described above.

[0059] <Second tubular connecting member 240> The second cylindrical connecting member 240 is a cylindrical member that connects the downstream end of the inner cylinder 10 and the upstream side of the third cylindrical member 250. The connection may be either direct or indirect. In the case of an indirect connection, for example, the downstream end of the outer cylinder 20 may be disposed between the downstream end of the inner cylinder 10 and the upstream side of the third cylindrical member 250.

[0060] It is preferable that the axial direction of the second cylindrical connecting member 240 coincides with the axial direction of the honeycomb structure 2000 , and the central axis of the second cylindrical connecting member 240 coincides with the central axis of the honeycomb structure 2000 .

[0061] The material of the second cylindrical connecting member 240 is not particularly limited, and the same material as that of the inner cylinder 10 described above can be used. The thickness of the second cylindrical connecting member 240 is not particularly limited, and can be the same as that of the inner cylinder 10 described above.

[0062] <Third tubular member 250> The third tubular member 250 is a member that is connected to the downstream side of the second tubular connecting member 240. It is preferable that the axial direction of the third cylindrical member 250 coincides with the axial direction of the honeycomb structure 2000 , and the central axis of the third cylindrical member 250 coincides with the central axis of the honeycomb structure 2000 .

[0063] The structure of the downstream end of the third cylindrical member 250 is not particularly limited, and can be adjusted appropriately depending on the shape of another component (such as a pipe) to which the downstream end of the third cylindrical member 250 is connected. For example, if the diameter of the other component is smaller than the diameter of the downstream end, the diameter of the downstream end can be reduced.

[0064] The material of the third cylindrical member 250 is not particularly limited, and the same material as that of the inner cylinder 10 described above can be used. The thickness of the third cylindrical member 250 is not particularly limited, and can be the same as that of the inner cylinder 10 described above.

[0065] <Opening and closing valve 260> The on-off valve 260 is disposed on the downstream end side of the first cylindrical member 210. The method for installing the on-off valve 260 is not particularly limited, but for example, the on-off valve 260 can be fixed to a shaft (not shown) that is rotatably supported by a bearing disposed radially outside the third cylindrical member 250 and that is disposed so as to pass through the third cylindrical member 250 and the first cylindrical member 210. The shape of the on-off valve 260 is not particularly limited, and an appropriate shape may be selected depending on the shape of the first cylindrical member 210 in which the on-off valve 260 is to be disposed.

[0066] The on-off valve 260 can be opened and closed by, for example, driving (rotating) a shaft with an actuator (not shown). That is, the on-off valve 260 can be opened and closed by rotating the on-off valve 260 together with the shaft. The on-off valve 260 is configured to be able to adjust the flow of the first fluid inside the first cylindrical member 210. Specifically, by closing the on-off valve 260 when promoting heat recovery, the first fluid can pass between the first cylindrical member 210 and the second cylindrical member 220 and circulate through the honeycomb structure 2000. Furthermore, by opening the on-off valve 260 when suppressing heat recovery, the first fluid can be circulated from the downstream end side of the first cylindrical member 210 to the third cylindrical member 250 and discharged to the outside of the heat exchanger 200.

[0067] The heat exchanger 200 according to the second embodiment of the present invention is provided with a flow path blocking member 50 as a boiling suppression section in the flow path 60 of the second fluid, thereby improving the heat recovery performance and the effect of suppressing melting damage to the components constituting the flow path 60 of the second fluid.

[0068] (Embodiment 3) The heat exchanger according to the third embodiment of the present invention differs from the heat exchanger 100 according to the first embodiment of the present invention in that at least a part of the outer casing 20 is provided with a flow path blocking treatment part as a boiling suppression part. FIG. 9 is a cross-sectional view of a heat exchanger according to a third embodiment of the present invention, taken along a line parallel to the flow direction of the first fluid. 9, a heat exchanger 300 according to a third embodiment of the present invention includes an inner cylinder 10, an outer cylinder 20, a supply pipe 30, and a discharge pipe 40. The heat exchanger 300 also includes a folded structure 23 formed on at least one end of the outer cylinder 20 as a flow path blocking treatment unit. In addition, components having the same reference numerals as those appearing in the description of the heat exchanger 100 according to embodiment 1 of the present invention are the same as the components of the heat exchanger 300 according to embodiment 3 of the present invention, and therefore their description will be omitted.

[0069] As described in the first embodiment, depending on the shape of the second fluid flow path 60, the flow of the second fluid may slow down around the axial end of the second fluid flow path 60. In this case, stagnation of the second fluid is likely to occur around the axial end of the second fluid flow path 60, and the temperature of the second fluid may continuously rise and boil. In this state, the heat recovery performance decreases and the surrounding components (the inner cylinder 10 and the outer cylinder 20) are likely to melt. Therefore, in the heat exchanger 300 of the third embodiment of the present invention, the folded structure 23 is formed so as to block the axial end of the flow path 60 for the second fluid, where the above-mentioned stagnation of the second fluid occurs and the second fluid is likely to boil. Note that, although Fig. 9 shows an example in which the folded structure 23 is formed on both end sides of the outer cylinder 20, the folded structure 23 may be formed on one end side of the outer cylinder 20.

[0070] The folded structure 23 can be manufactured by bending the outer cylinder 20. The type of bending is not particularly limited, and various known methods can be used.

[0071] FIG. 10 is a cross-sectional view of another heat exchanger according to the third embodiment of the present invention, taken along a line parallel to the flow direction of the first fluid. 10, a heat exchanger 400 according to the third embodiment of the present invention includes an inner cylinder 10, an outer cylinder 20, a supply pipe 30, and a discharge pipe 40. The heat exchanger 400 also includes a weld bead portion 24 on at least one end of the outer cylinder 20 as a flow path blockage treatment portion. In addition, components having the same reference numerals as those appearing in the description of the heat exchanger 100 according to embodiment 1 of the present invention are the same as those of another heat exchanger 400 according to embodiment 3 of the present invention, and therefore their description will be omitted.

[0072] In the heat exchanger 400 of the third embodiment of the present invention, the weld bead portions 24 are formed so as to block the axial ends of the flow paths 60 for the second fluid, where the second fluid is likely to stagnate and boil as described above. Note that, although Fig. 10 shows an example in which the weld bead portions 24 are formed on both end sides of the outer casing 20, the weld bead portions 24 may be formed on one end side of the outer casing 20.

[0073] The weld bead portion 24 is a portion where the outer cylinder 20 melts and solidifies when the outer cylinder 20 is welded to the inner cylinder 10. The welding method is not particularly limited, and arc welding (for example, TIG welding, MIG welding) or the like can be used.

[0074] Although not shown, the heat exchanger 300 according to the third embodiment of the present invention may have both the folded structure 23 and the weld bead portion 24 formed as a flow path blocking treatment portion on at least one end side of the outer cylinder 20. With this configuration, it is possible to stably prevent the second fluid from stagnating and boiling.

[0075] The heat exchangers 300 and 400 according to the third embodiment of the present invention have a flow path occlusion treatment section (folded structure 23 and / or weld bead section 24) formed in the outer tube 20 as a boiling suppression section within the flow path 60 of the second fluid, thereby improving the heat recovery performance and also improving the effect of suppressing melting damage to the components that make up the flow path 60 of the second fluid.

[0076] (Embodiment 4) The heat exchanger according to the fourth embodiment of the present invention differs from the heat exchanger 100 according to the first embodiment of the present invention in that it includes a diameter-reducing structure for the supply port 21 as a boiling suppression section. FIG. 11 is a cross-sectional view of a heat exchanger according to a fourth embodiment of the present invention, taken along a line parallel to the flow direction of the first fluid. 11, a heat exchanger 500 according to the fourth embodiment of the present invention includes an inner cylinder 10, an outer cylinder 20, a supply pipe 30, and a discharge pipe 40. The heat exchanger 500 also includes a diameter-reducing structure 25 for the supply port 21 as a flow path blocking treatment unit. Here, in this specification, the "diameter-reducing structure 25 of the supply port 21" means a structure of the supply port 21 or its periphery that is designed to reduce the diameter of the supply port 21. In addition, components having the same symbols as those appearing in the description of the heat exchanger 100 according to embodiment 1 of the present invention are the same as the components of the heat exchanger 500 according to embodiment 4 of the present invention, and therefore their description will be omitted.

[0077] Depending on the shape of the flow path 60 for the second fluid, the flow of the second fluid is likely to slow down around the supply port 21 (the connection between the outer casing 20 and the supply pipe 30). As a result, the second fluid is likely to stagnate around the supply port 21, causing the temperature of the second fluid to continuously rise and boil. In this state, the heat recovery performance is reduced and the surrounding components (the outer casing 20 and the supply pipe 30) are more likely to melt. Therefore, in the heat exchanger 500 of embodiment 4 of the present invention, a diameter-reducing structure 25 is provided at the supply port 21 where the second fluid is likely to stagnate and boil as described above, thereby increasing the flow rate of the second fluid flowing into the second fluid flow path 60 and suppressing stagnation of the second fluid around the supply port 21. 11 illustrates a case where the diameter of supply port 21 is smaller than the diameter of discharge port 22 as diameter-reducing structure 25, but the diameter of supply port 21 may be the same as the diameter of discharge port 22, and a ring-shaped member (such as a washer) for reducing the diameter may be provided at supply port 21. Also, the diameter of supply port 21 may be reduced from the outside by machining or the like.

[0078] The diameter of the diameter-reducing structure 25 of the supply port 21 is preferably 65 to 95% of the diameter of the discharge port 22. By making the diameter of the supply port 21 95% or less of the diameter of the discharge port 22, the above-mentioned effect can be stably obtained. Furthermore, by making the diameter of the supply port 21 65% or more of the diameter of the discharge port 22, a decrease in pressure loss within the flow path 60 of the second fluid can be suppressed. In particular, if the diameter of the supply port 21 is less than 65% of the diameter of the discharge port 22, the second fluid is likely to stagnate around the diameter-reducing structure 25 (on the back side of the connection portion).

[0079] In the heat exchanger 500 according to the fourth embodiment of the present invention, it is preferable that the supply port 21 and the discharge port 22 are provided in the axial center of the outer cylinder 20, and that the supply pipe 30 and the discharge pipe 40 are connected to the supply port 21 and the discharge port 22, respectively. It is also preferable that the supply pipe 30 and the discharge pipe 40 extend in different directions. With this configuration, the effect of the diameter-reducing structure 25 of the supply port 21 can be stably obtained.

[0080] The heat exchanger 500 according to the fourth embodiment of the present invention is provided with a diameter-reducing structure 25 at the supply port 21 as a boiling suppression section, thereby improving the heat recovery performance and the effect of suppressing melting damage to the components constituting the flow path 60 of the second fluid.

[0081] (Embodiment 5) The heat exchanger according to the fifth embodiment of the present invention differs from the heat exchanger 100 according to the first embodiment of the present invention in that at least a part of the inner cylinder 10 is provided with a high thermal resistance treated portion as a boiling suppression portion. FIG. 12 is a cross-sectional view of a heat exchanger according to a fifth embodiment of the present invention, taken along a line parallel to the flow direction of the first fluid. 12, a heat exchanger 600 according to the fifth embodiment of the present invention includes an inner cylinder 10, an outer cylinder 20, a supply pipe 30, and a discharge pipe 40. The heat exchanger 600 also includes a high heat resistance treated portion 11 in at least a part of the inner cylinder 10. In addition, components having the same symbols as those appearing in the description of the heat exchanger 100 according to embodiment 1 of the present invention are the same as the components of the heat exchanger 600 according to embodiment 5 of the present invention, and therefore their description will be omitted.

[0082] As described in the first embodiment, depending on the shape of the second fluid flow path 60, the flow of the second fluid may slow down around the axial end of the second fluid flow path 60. In this case, stagnation of the second fluid is likely to occur around the axial end of the second fluid flow path 60, and the temperature of the second fluid may continuously rise and boil. In this state, the heat recovery performance decreases and the surrounding components (the inner cylinder 10 and the outer cylinder 20) are likely to melt. Therefore, in the heat exchanger 600 of the fifth embodiment of the present invention, a high thermal resistance treatment portion 11 is provided on the inner cylinder 10 facing the second fluid flow path 60 where the second fluid is likely to stagnate and boil. By providing the high thermal resistance treatment portion 11, the heat of the first fluid is less likely to be transferred to the surface of the high thermal resistance treatment portion 11 facing the second fluid flow path 60, making it less likely for the second fluid to boil even if it stagnates. Furthermore, when the flow path direction of the first fluid is used as a reference, the heat of the first fluid is transferred to a region of the inner cylinder 10 located upstream of the heat recovery member 1, which can prevent the heat of the first fluid from decreasing before being recovered by the heat recovery member 1. As a result, providing the high thermal resistance treatment portion 11 improves heat recovery performance. Although Figure 12 shows an example in which high heat resistance treatment 11 is formed on both end sides of the inner tube 10, high heat resistance treatment 11 may also be formed on one end side of the inner tube 10.

[0083] Here, in this specification, the high heat resistance treated portion 11 means a portion of the inner cylinder 10 that has been treated to have higher thermal resistance than portions other than the high heat resistance treated portion 11. Specifically, the thermal resistance of the high heat resistance treated portion 11 is preferably 0.01 K / W or more, and more preferably 0.02 K / W or more.

[0084] The high heat resistance treated portion 11 is preferably provided in a portion facing a length region from the end of the second fluid flow path 60 that is 50% or less of the maximum flow path height of the second fluid flow path 60. Since the second fluid is likely to stagnate in the second fluid flow path 60 facing such a region, providing the high heat resistance treated portion 11 in this portion makes it possible to stably suppress boiling of the second fluid.

[0085] The high-heat-resistance treated portion 11 may be formed, for example, by increasing the thickness of the portion of the inner tube 10 that will become the high-heat-resistance treated portion 11 compared to the remaining portions. Alternatively, the portion that will become the high-heat-resistance treated portion 11 may be formed from a material with a higher thermal resistance than the remaining portions. Specifically, impurities may be introduced into the portion of the inner tube 10 that will become the high-heat-resistance treated portion 11, or this portion may be formed from a different material. Furthermore, the portion of the inner tube 10 that will become the high-heat-resistance treated portion 11 may be subjected to a hardening process to have a large number of crystal grain boundaries different from the remaining portions. Furthermore, a heat-resistant sheet may be attached to the surface of the portion of the inner tube 10 that will become the high-heat-resistance treated portion 11, or a heat-resistant paint may be applied thereto. Furthermore, the portion of the inner tube 10 that will become the high-heat-resistance treated portion 11 may be processed to have a multilayer structure.

[0086] The heat exchanger 600 according to the fifth embodiment of the present invention is provided with a high thermal resistance treatment section 11 in at least a part of the inner tube 10 as a boiling suppression section, thereby improving the heat recovery performance and the effect of suppressing melting damage to the components constituting the flow path 60 of the second fluid.

[0087] (Embodiment 6) The heat exchanger according to the sixth embodiment of the present invention differs from the heat exchanger 100 according to the first embodiment of the present invention in that at least a part of the inner cylinder 10 is provided with a smooth surface portion as a boiling suppression portion. FIG. 13 is a cross-sectional view of a heat exchanger according to a sixth embodiment of the present invention, taken along a line parallel to the flow direction of the first fluid. 13, a heat exchanger 700 according to the sixth embodiment of the present invention includes an inner cylinder 10, an outer cylinder 20, a supply pipe 30, and a discharge pipe 40. The heat exchanger 700 also has a smoothed surface portion 12 on at least a part of the inner cylinder 10. In addition, components having the same symbols as those appearing in the description of the heat exchanger 100 according to embodiment 1 of the present invention are the same as the components of the heat exchanger 700 according to embodiment 6 of the present invention, and therefore their description will be omitted.

[0088] As described in the first embodiment, depending on the shape of the second fluid flow path 60, the flow of the second fluid may slow down around the axial end of the second fluid flow path 60. In this case, stagnation of the second fluid is likely to occur around the axial end of the second fluid flow path 60, and the temperature of the second fluid may continuously rise and boil. In this state, the heat recovery performance decreases and the surrounding components (the inner cylinder 10 and the outer cylinder 20) are likely to melt. Therefore, in the heat exchanger 700 of the sixth embodiment of the present invention, a smoothed surface portion 12 is provided on the inner cylinder 10 facing the second fluid flow path 60, where the second fluid is likely to stagnate and boil. Since the heat transfer of the inner cylinder 10 decreases as the surface area of ​​the inner cylinder 10 decreases, providing the smoothed surface portion 12 in this portion makes it difficult for the heat of the first fluid to be transferred to the surface of the smoothed surface portion 12 facing the second fluid flow path 60. This makes it difficult for the second fluid to boil even if it stagnates. Furthermore, when the flow direction of the first fluid is used as a reference, the heat of the first fluid is transferred to a region of the inner cylinder 10 located upstream of the heat recovery member 1, which can prevent the heat of the first fluid from being reduced before being recovered by the heat recovery member 1. As a result, providing the smoothed surface portion 12 improves heat recovery performance. Although Figure 13 shows an example in which smoothed surface portions 12 are formed on both end sides of the inner tube 10, the smoothed surface portion 12 may also be formed on one end side of the inner tube 10.

[0089] Although there are no particular limitations on the surface roughness Ra of the smoothed surface portion 12, it is preferable that it be 10 μm or less. By controlling the surface roughness Ra within this range, boiling of the second fluid can be stably suppressed. Here, in this specification, the surface roughness Ra means the arithmetic mean roughness measured in accordance with JIS B0601:2013.

[0090] The smooth surface portion 12 may be formed on either the inner surface or the outer surface of the inner cylinder 10, but is preferably formed on both surfaces. By forming the smooth surface portion 12 on both surfaces of the inner cylinder 10, the effect of suppressing boiling of the second fluid is enhanced.

[0091] The smooth surface portion 12 is preferably provided in a portion facing a length region from the end of the second fluid flow path that is 50% or less of the maximum flow path height of the second fluid flow path 60. Since the second fluid is likely to stagnate in the second fluid flow path 60 facing such a region, providing the smooth surface portion 12 in this portion makes it possible to stably suppress boiling of the second fluid.

[0092] The smooth surface portion 12 can be formed by polishing the portion of the inner cylinder 10 that will become the smooth surface portion 12. The polishing conditions and the like can be adjusted appropriately depending on the type of inner cylinder 10, and are not particularly limited.

[0093] The heat exchanger 700 according to the sixth embodiment of the present invention is provided with a smooth surface portion 12 on at least a part of the inner tube 10 as a boiling suppression portion, thereby improving the heat recovery performance and the effect of suppressing melting damage to the components constituting the flow path 60 of the second fluid. [Explanation of symbols]

[0094] 1 Heat recovery components 2 Downstream end 10 Inner cylinder 11 High heat resistance processing section 12 Smoothing section 20 outer cylinder 21 Supply port 22 Outlet 23 Folded structure 24 Weld bead 25 Diameter reduction structure 30 Supply pipe 40 Discharge pipe 50 Flow path blocking member 60 second fluid flow path 61a Upstream end 61b Downstream end 100, 200, 300, 400, 500, 600, 700 heat exchanger 210 First cylindrical member 220 Second cylindrical member 230 First cylindrical connecting member 240 second tubular connecting member 250 Third cylindrical member 260 Opening and Closing Valve 270 Sealing material 1000, 2000 Honeycomb structure 1100 Peripheral wall 1200 cells 1300 Bulkhead 1400 Inner wall C1, C2 Axial center

Claims

1. a heat recovery member through which the first fluid can flow; an inner cylinder that accommodates the heat recovery member; an outer cylinder having a supply port capable of supplying a second fluid and a discharge port capable of discharging the second fluid, the outer cylinder being disposed radially outside the inner cylinder at a distance so as to form a flow path for the second fluid between the outer cylinder and the inner cylinder; a supply pipe connected to the supply port; a discharge pipe connected to the discharge port; Equipped with When a flow path direction of the first fluid is taken as a reference, the supply port of the outer cylinder is located downstream of a center of the outer cylinder in an axial direction, and the discharge port of the outer cylinder is located upstream of the center of the outer cylinder in an axial direction, A heat exchanger in which the heat recovery member is arranged so that, when the flow direction of the first fluid is used as a reference, the axial center of the heat recovery member is downstream of the axial center of the flow path of the second fluid, and the downstream end of the heat recovery member is upstream of the downstream end of the flow path of the second fluid.

2. 2. The heat exchanger according to claim 1, wherein, based on the flow direction of the first fluid, the downstream end of the heat recovery member is positioned upstream of the downstream end of the flow path of the second fluid, at a distance of 10 mm or more.

3. 3. The heat exchanger according to claim 1, wherein, when the flow direction of the first fluid is used as a reference, the downstream end of the heat recovery member is arranged upstream from the downstream end of the flow path of the second fluid by 10% or more of the length of the flow path of the second fluid.

4. a boiling suppression portion that suppresses boiling of the second fluid is provided in the flow path of the second fluid, the boiling suppression portion is one or more selected from a flow path closing member arranged to close at least a portion of the flow path of the second fluid, a flow path closing treatment portion of at least a portion of the outer cylinder, a diameter-reducing structure portion of the supply port, a high heat resistance treatment portion of at least a portion of the inner cylinder, and a smooth surface portion of at least a portion of the inner cylinder, the flow path closing member is disposed so as to close at least one end of the flow path of the second fluid, and closes a length region of the flow path of the second fluid from the end of the flow path of the second fluid to 50% or less of a maximum flow path height of the flow path of the second fluid, the flow path blocking treatment portion is a folded structure and / or a weld bead portion formed on at least one end side of the outer cylinder, the diameter-reducing structure of the supply port is such that the diameter of the supply port is 65 to 95% of the diameter of the discharge port; the high thermal resistance treated portion is provided in a portion facing a length region of 50% or less of a maximum flow path height of the flow path of the second fluid from an end of the flow path of the second fluid, and has a thermal resistance of 0.01 K / W or more; The heat exchanger according to any one of claims 1 to 3, wherein the smoothing portion is provided in a portion facing a length region from the end of the flow path of the second fluid to 50% or less of the maximum flow path height of the flow path of the second fluid, and has a surface roughness Ra of 10 μm or less.

5. The heat exchanger according to claim 4 , wherein the passage blocking member is a ring-shaped member.

6. The heat exchanger according to any one of claims 1 to 5, wherein the heat recovery member is a honeycomb structure having an outer peripheral wall and a plurality of partition walls disposed inside the outer peripheral wall, extending from a first end face to a second end face to define a plurality of cells that serve as a flow path for a first fluid, or a honeycomb structure having an outer peripheral wall, an inner peripheral wall, and partition walls disposed between the outer peripheral wall and the inner peripheral wall, extending from a first end face to a second end face to define a plurality of cells that serve as a flow path for a first fluid.

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