WO2020031780A1

WO2020031780A1 - Method for manufacturing heat exchanger

Info

Publication number: WO2020031780A1
Application number: PCT/JP2019/029706
Authority: WO
Inventors: 祥啓古賀; 建人櫻井; 長谷川　学; 則義宮嶋; 彰洋大井
Original assignee: イビデン株式会社
Priority date: 2018-08-10
Filing date: 2019-07-29
Publication date: 2020-02-13
Also published as: JP2020026908A

Abstract

This method for manufacturing a heat exchanger includes a molding step in which a raw material composition containing silicon carbide particles is used to form a molded body which is provided with first flow passages R1 and a plurality of second flow passages R2. This molding step includes: a first molding step for forming a sheet-like first molded body which forms the first flow passages R1 in the molded body, and which has on the surface thereof a plurality of protrusions 25 scattered in the flow direction of a first fluid and in a direction crossing said flow direction; a second molding step for forming a sheet-like second molded body which forms the second flow passages R2 in the molded body; and a stacking step for stacking the first molded body and the second molded body together.

Description

Heat exchanger manufacturing method

The present invention relates to a method for manufacturing a heat exchanger.

Patent Literature 1 describes a method for manufacturing a heat exchanger.
In this manufacturing method, as shown in FIG. 13, a plurality of ribs 53 are formed on the surface of a ceramic sheet material 51 using a cylindrical roller 52. A laminate is prepared by laminating a plurality of sheet members 51 having the ribs 53 formed thereon, and the laminate is fired, and the fired laminate is housed in a case to manufacture a heat exchanger.

JP-A-2002-5593

In the heat exchanger of Patent Document 1, the plurality of ribs 53 are provided continuously from one end of the sheet material 51 to the other end thereof. Since the fluid flows between the plurality of ribs 53 along the ribs 53, the flow of the fluid tends to be in a rectified state. When the flow of the fluid is in a rectified state, it is difficult to perform heat transport. Therefore, there is a problem that the heat exchange efficiency is low. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method of manufacturing a heat exchanger that can improve heat exchange efficiency.

A method for manufacturing a heat exchanger according to an aspect of the present disclosure includes a plurality of first flow paths, a plurality of second flow paths, and a partition wall that partitions the first flow path and the second flow path. A method of manufacturing a heat exchanger made of silicon carbide in which heat exchange is performed between the first fluid flowing through the first flow passage and the second fluid flowing through the second flow passage via the partition wall. And a forming step of forming a molded body having the first flow passage and the second flow passage by using a raw material composition containing silicon carbide particles, and degreasing the molded body to produce a porous body. A degreasing step, and an impregnating step of impregnating the porous body with metallic silicon, wherein the forming step is a part of the formed body where the first flow passage is formed, and a flow direction of the first fluid and A plurality of projections scattered in a direction intersecting the distribution direction are provided on the surface. A first molding step of molding a first molded body having a shape, a second molding step of molding a second molded body having a portion forming the second flow passage in the molded body, And a laminating step of laminating the second molded body.

According to the above configuration, the first molded body is formed with the plurality of protrusions scattered in the flow direction of the first fluid and the direction intersecting the flow direction, so that the first fluid flowing through the first flow passage is formed. It becomes difficult to form a boundary layer that inhibits the transfer of heat formed between the fluid and the partition wall that forms the first flow passage. Thereby, heat transfer of the first fluid flowing through the first flow passage can be promoted, so that heat exchange efficiency can be improved.

In one aspect of the present disclosure, in the laminating step, the tip of the convex portion of the first molded body is brought into contact with the first molded body or the second molded body superimposed on the first molded body. May be. According to the above configuration, heat conduction between the first molded body provided with the convex part and another first molded body or the second molded body laminated on the first molded body via the convex part. Can be promoted. Therefore, the heat exchange efficiency can be improved.

In one embodiment of the present disclosure, in the first forming step, the convex portion may be formed by press forming. According to the above configuration, by forming the projections by press molding, it becomes easy to make the projections finer or to form the projections in a dense state.

According to an aspect of the present disclosure, a side wall is provided at a pair of opposite ends of the first molded body on which the protrusion is formed, and the side wall may be formed by the press molding. . According to the above configuration, since the convex portion and the side wall can be formed at the same time, the heat exchanger can be manufactured efficiently.

In one embodiment of the present disclosure, the protrusion may be formed to have a prismatic or elliptical shape. According to the above configuration, the flow resistance of the first fluid in the convex portion can be reduced, and the heat transport can be further promoted.

According to one or more aspects of the present disclosure, the heat exchange efficiency of the heat exchanger can be improved.

The perspective view of a heat exchanger. FIG. 2 is a sectional view taken along line 2-2 of FIG. 1. FIG. 3 is a sectional view taken along line 3-3 in FIG. 1. Explanatory drawing of a molding process. Explanatory drawing of a 1st shaping | molding process. Explanatory drawing of a 2nd shaping | molding process. Explanatory drawing of a lamination process. Explanatory drawing which shows the state which arrange | positioned the laminated body in the container. 4 is a graph showing a temperature change in the container. Sectional drawing of the width direction of a convex part. Sectional drawing of the width direction of the convex part of the example of a change. Sectional drawing of the width direction of the convex part of another modification. Explanatory drawing of the shaping process in the heat exchanger of a prior art.

Hereinafter, an embodiment of the heat exchanger will be described.
As shown in FIG. 1, the heat exchanger 10 of the present embodiment includes a first circulation part (gas circulation part 20) having a first circulation passage (gas circulation passage R1) and a second circulation passage (heat medium circulation passage). R2) and a second circulation section (heat medium circulation section 30). Heat medium circulating portions 30 are arranged at both ends in the juxtaposition direction, and three layers of gas circulating portions 20 are arranged inside each heat medium circulating portion 30. One layer of the heat medium circulation unit 30 is arranged inside the gas circulation unit 20. The heat exchange is performed between the gas flowing through the gas flow passage R1 and the liquid heat medium flowing through the heat medium flow passage R2.

Next, the heat medium circulating unit 30 will be described.
As shown in FIGS. 1 and 2, the heat medium circulating portion 30 includes a bottom wall 31 formed of a rectangular plate, a side wall 32 erected from a pair of opposite ends of the bottom wall 31, And a central wall 33 standing from the bottom wall 31 at an intermediate position of the side wall 32. The heat medium circulating unit 30 is configured in the same shape as the bottom wall 31, and includes a top wall 34 disposed on the side wall 32 and the center wall 33. By disposing the top wall 34 on the side wall 32 and the center wall 33, two through holes C2 forming the heat medium flow passage R2 are formed between the bottom wall 31 and the top wall 34. Therefore, the bottom wall 31, the side wall 32, the center wall 33, and the top wall 34 function as partition walls that partition the heat medium passage R2.

熱 The heat medium circulating sections 30 located at the center and the lower end of the heat exchanger 10 in FIG. 1 use the bottom wall 21 of the gas circulating section 20 described later as the top wall 34. In other words, the heat medium circulating portions 30 located at the central portion and the lower end portion of the heat exchanger 10 also use the bottom wall 21 of the gas circulating portion 20 laminated on the upper side as the top wall 34.

Here, as shown in FIG. 1, the direction in which the through-holes C2 extend in the heat exchanger 10 is referred to as “width direction DX”, the direction in which the through-holes C2 are arranged is referred to as “front-back direction DY”, And the direction in which the heat medium circulating unit 30 is juxtaposed is referred to as “vertical direction DZ”.

As shown in FIG. 2, an inlet 15a for the heat medium is formed at one end of the through hole C2 in the width direction DX, and an outlet 15b for the heat medium is formed at the other end of the through hole C2 in the width DX. A heat medium passage R2 is formed between the inflow port 15a and the outflow port 15b. The thickness of the bottom wall 31 and the top wall 34 in the heat medium circulating portion 30 is preferably, for example, 0.1 to 1.0 mm. The thickness of the side wall 32 and the center wall 33 in the heat medium circulating section 30 is preferably, for example, 0.1 to 1.0 mm. As the heat medium flowing through the heat medium flow passage R2, for example, a known liquid heat medium can be used. Known heat media include, for example, cooling water (Long Life Coolant: LLC) and organic solvents such as ethylene glycol.

Next, the gas circulation unit 20 will be described.
As shown in FIGS. 1 and 3, the gas flow portion 20 includes a bottom wall 21 formed of a rectangular plate, and a side wall 22 erected from a pair of opposite ends of the bottom wall 21 in the width direction DX. And a top wall 23 configured in the same shape as the bottom wall 21 and disposed on the side wall 22. By disposing the top wall 23 on the side wall 22, a through hole C <b> 1 forming the gas flow path R <b> 1 is formed between the bottom wall 21 and the top wall 23. Therefore, the bottom wall 21, the side wall 22, and the top wall 23 function as partition walls that partition the gas passage R1.

ガス The gas flow section 20 located below the heat medium flow section 30 in FIG. 1 uses the bottom wall 31 of the heat medium flow section 30 as the top wall 23. In addition, the gas circulation unit 20 located below the portion where the gas circulation units 20 are stacked uses the bottom wall 21 of the gas circulation unit 20 located above as the top wall 23. That is, the gas distribution unit 20 also uses the heat medium distribution unit 30 or the

bottom walls

31 and 21 of the gas distribution unit 20 stacked on the upper side as the top wall 23.

As shown in FIG. 3, a gas inlet 16a is formed at one end of the through-hole C1 in the front-rear direction DY, and a gas outlet 16b is formed at the other end of the through-hole C1 in the front-rear direction. A gas flow passage R1 is formed between the gas flow passage 16 and the outlet 16b.

On the surface of the bottom wall 21 of the gas flow section 20, a plurality of projections 25 are provided in a dotted manner in a gas flow direction and a direction intersecting the gas flow direction. In other words, a plurality of protrusions 25 are provided along the front-rear direction DY that is the gas flow direction, and a plurality of protrusions 25 are provided along the width direction DX that intersects the gas flow direction. Specifically, as shown in FIG. 3, the plurality of protrusions 25 have a row of protrusions arranged at equal intervals along the width direction DX, and the plurality of protrusions 25 are aligned along the front-rear direction DY. A plurality are arranged at intervals. Convex rows adjacent to each other in the front-rear direction DY are arranged such that the positions of the convex sections 25 are shifted in the width direction DX by の of the interval between the convex sections 25 in each convex row. In other words, in every other row of convex portions in the front-back direction DY, the positions of the convex portions 25 in the width direction DX are the same.

凸 As shown in FIGS. 1 and 3, the projection 25 has a tapered shape protruding in a curved shape. Specifically, the cross-sectional shape orthogonal to the width direction DX and the cross-sectional shape orthogonal to the front-rear direction DY are both shapes obtained by cutting an ellipse along a short axis. The cross-sectional shape of the convex portion 25 is an elliptical shape extending in the front-rear direction DY. The dimension in the vertical direction DZ, which is the height of the projection 25, may be equal to the dimension in the vertical direction DZ of the side wall 22, and is preferably, for example, 1.0 to 4.0 mm. The dimension of the projection 25 in the width direction DX is preferably, for example, 0.1 to 1.0 mm. The dimension of the protrusion 25 in the front-rear direction DY is preferably, for example, 1.0 to 5.0 mm. The interval in the width direction DX between the projections 25 in the row of projections is preferably, for example, 0.4 to 4.0 mm. The distance between the rows of convex portions in the front-rear direction is preferably, for example, 1.0 to 5.0 mm.

底 The thickness of the bottom wall 21 and the top wall 23 in the gas flow section 20 is preferably, for example, 0.1 to 1.0 mm. The thickness of the side wall 22 in the gas flow section 20 is preferably, for example, 0.1 to 1.0 mm. Examples of the gas flowing through the gas flow passage R1 include an exhaust gas of an internal combustion engine and an intake gas to the internal combustion engine.

(4) The material forming the heat medium distribution unit 30 and the gas distribution unit 20 is a silicon carbide material containing silicon carbide as a main component. A material containing silicon carbide as a main component has high thermal conductivity and can increase heat exchange efficiency. Here, “main component” means 50% by mass or more.

Next, the flow path configuration of the heat exchanger 10 will be described.
As shown in FIG. 1, the heat exchanger 10 is configured in a state where the gas circulation unit 20 and the heat medium circulation unit 30 are connected. The through-hole C2 of the heat medium circulating section 30 and the through-hole C1 of the gas circulating section 20 are configured to extend in directions orthogonal to each other. Specifically, the through hole C2 of the heat medium circulating portion 30 is configured to extend in the width direction DX, and the through hole C1 of the gas circulating portion 20 is configured to extend in the front-rear direction DY. Then, heat exchange is performed between the gas flowing through the through-hole C1 of the gas flow part 20 and the heat medium flowing through the through-hole C2 of the heat medium flow part 30 via the partition wall.

One manufacturing method of the heat exchanger 10 will be described with reference to FIGS.
The heat exchanger 10 is manufactured through a molding process, a degreasing process, and an impregnation process described below.

(Molding process)
The forming step includes a first forming step of forming a sheet-shaped first formed body 18, a second forming step of forming a sheet-shaped second formed body 19, and forming the first formed body 18 and the second formed body 19. And a laminating step of laminating.

[First molding step]
As a raw material composition used for molding the first molded body 18, a clay-like mixture containing silicon carbide particles, an organic binder, and a dispersion medium is prepared.

Examples of the organic binder include polyvinyl alcohol, methyl cellulose, ethyl cellulose, and carboxymethyl cellulose. Among these organic binders, methyl cellulose and carboxymethyl cellulose are particularly preferred. Further, only one kind of the above organic binders may be used, or two or more kinds may be used in combination.

Examples of the dispersion medium include water and organic solvents. Examples of the organic solvent include ethanol. Further, only one of the above dispersion media may be used, or two or more of them may be used in combination.

In addition, other components may be further contained in the mixture. Other components include, for example, ceramic particles, a plasticizer, and a lubricant made of a material other than silicon carbide. Examples of the ceramic particles made of a material other than silicon carbide include ceramic particles made of a carbide such as tantalum carbide and tungsten carbide, and nitrides such as aluminum nitride, silicon nitride, and boron nitride. Examples of the plasticizer include polyoxyalkylene compounds such as polyoxyethylene alkyl ether and polyoxypropylene alkyl ether. Examples of the lubricant include glycerin.

As shown in FIG. 4, a rectangular plate-shaped molded body 17 is formed using the clay-like mixture. The molded body 17 can be molded by, for example, extrusion molding.
Next, as shown in FIG. 5, the rectangular plate-shaped molded body 17 is press-formed to form a bottom wall 21 made of a rectangular plate material and a pair of opposite sides in the width direction DX of the bottom wall 21. The first molded body 18 having the side wall 22 erected from the end is molded. The bottom wall 21 is provided with a plurality of projections 25 projecting upward in the vertical direction DZ. In the press molding, a flat mold (not shown) is arranged below the rectangular plate-shaped molded body 17, and the upper and lower surfaces of the first molded body 18 are located above the rectangular plate-shaped molded body 17. An oppositely configured mold (not shown) is arranged, and pressing is performed in a direction in which the molds approach each other from above and below. The first molded body 18 having the convex portions 25 and the side walls 22 is obtained by pressing the rectangular plate-shaped molded body 17 in the thickness direction. Since the convex portions 25 according to the shape of the mold can be produced by press molding, it becomes easy to make the convex portions 25 finer or to form the convex portions 25 in a dense state.

[Second molding step]
As a raw material composition used for molding the second molded body 19, a clay-like mixture composed of the same raw material composition as the first molded body 18 is used. Using this clay-like mixture, a rectangular plate-like molded body 17 is molded in the same manner as in the first molding step.

(6) Next, as shown in FIG. 6, the sheet-shaped second formed body 19 having the side wall 32 and the central wall 33 is formed by press-forming the rectangular plate-shaped formed body 17. In the press molding, a flat plate-shaped mold (not shown) is arranged below the rectangular plate-shaped molded body 17, and the upper and lower surfaces of the second molded body 19 are located above the rectangular plate-shaped molded body 17. Is performed by placing a mold (not shown) having the reverse configuration and pressing the mold in a direction in which the molds approach each other from above and below. The second molded body 19 having the side wall 32 and the center wall 33 is obtained by pressing the rectangular plate-shaped molded body 17 in the thickness direction.

[Lamination process]
As shown in FIG. 7, the first compact 18 and the second compact 19 are laminated in a predetermined order to form a compact (laminated body 24). On the side wall 22 of the first compact 18, the bottom wall 21 of the other first compact 18 or the bottom wall 31 of the second compact 19 is placed. The bottom wall 21 of the first molded body 18 is placed on the side wall 32 of the second molded body 19. On the upper part of the second molded body 19 located at the upper end, a rectangular plate material separately molded using the same clay-like mixture as the raw material composition of the second molded body is arranged as the top wall 34. Since the convex portion 25 and the side wall 22 provided on the first molded body 18 have the same height, the bottom of the other first molded body 18 placed on the side wall 22 of the first molded body 18 The lower end of the wall 21 or the lower end of the bottom wall 31 of the second molded body 19 is brought into contact with the tip of the projection 25. The upper surface side of the first molded body 18 constitutes a gas flow section 20 through a degreasing step and an impregnation step described later. The upper surface side of the second molded body 19 constitutes the heat medium flowing section 30 through a degreasing step and an impregnation step described later.

The first molded body 18 and the second molded body 19 may be laminated via an adhesive layer. As the adhesive, a mixture of an inorganic binder and inorganic particles can be used. Examples of the inorganic binder include silica sol and alumina sol, and examples of the inorganic particles include silicon carbide and silicon nitride. A drying process is performed on the stacked body 24 as necessary. Specific examples of the drying treatment include a drying treatment using a microwave dryer, a hot air dryer, a dielectric dryer, a reduced pressure dryer, a vacuum dryer, a freeze dryer, or the like.

(Degreasing process)
The degreasing step is a step of heating and burning off the organic components contained in the laminate. Through the degreasing step, a porous body having a skeleton portion arranged in a state where the silicon carbide particles are in contact with each other is obtained.

(Impregnation step)
The impregnation step is a step of impregnating the interior of the porous partition wall with metallic silicon. Through the impregnation step, metallic silicon is filled between the silicon carbide particles constituting the partition wall.

Here, in the manufacturing method of the present embodiment, the degreasing step and the impregnating step are continuously performed by multi-stage heat treatment in different temperature ranges.
As shown in FIG. 8, the laminate 24 is placed in a heat-resistant container 40 having a bottomed box shape made of graphite or the like. FIG. 8 illustrates the laminated body 24 with its cross-sectional shape omitted. The stacked body 24 is placed on the support 41 disposed on the bottom surface of the container 40, and thus is disposed in the container 40 via the support 41. The support 41 is formed in a size and a shape that comes into contact with only a part of the lower surface of the laminate 24, and supports the laminate 24 at one or several points on the lower surface of the laminate 24. The number of supports 41 may be one or more.

形状 Examples of the shape of the support 41 include a prism, a cylinder, a truncated pyramid, and a truncated cone. Among these, the truncated pyramid shape and the truncated cone shape are particularly preferable in that the number of contacts with the lower surface of the laminate 24 can be reduced.

The support member 41 is formed of a porous material having continuous pores large enough to cause a capillary phenomenon. Examples of the porous material forming the support 41 include a porous material made of silicon carbide and a porous material made of carbon such as graphite. The porosity of the porous material constituting the support 41 is, for example, 20 to 60%.

{Circle around (4)} Solid metal silicon 42 such as powder, granule, or lump is placed in the gap S between the bottom surface of the container 40 and the laminate 24 placed on the support 41. As the metal silicon 42, it is preferable to use metal silicon having a purity of less than 98%. Solid metallic silicon tends to have a lower melting point as its purity decreases. Therefore, by using low-purity metallic silicon, the heating temperature required for the impregnation step can be kept low. As a result, manufacturing costs can be reduced. The purity of the metallic silicon is, for example, 95% or more.

The amount of the metallic silicon 42 contained in the container 40 is, for example, an amount corresponding to the sum of the pore volume of the porous body obtained from the laminate 24 and the pore volume of the support 41 (for example, 1.00 to 1.00 of the above sum). 1.05 times the volume). In this case, the porosity of the heat exchanger 10 can approach 0%. In addition, the usage amount of the metal silicon 42 is suppressed, and the manufacturing cost can be suppressed.

As described above, with the laminate and the metal silicon 42 arranged in the container 40, the container 40 is placed under an inert atmosphere such as argon or nitrogen or under vacuum using a known heating means such as a firing furnace. Heat. At this time, the container 40 is subjected to multi-stage heating in different temperature ranges.

Specifically, as shown in FIG. 9, the primary heating is performed by raising the temperature in the container 40 to the first temperature and maintaining the temperature at the first temperature for a certain time. Thereafter, the temperature inside the container 40 is increased to a second temperature higher than the first temperature, and is maintained for a certain period of time to perform secondary heating. Then, the temperature in the container 40 is decreased.

Primary heating is a heat treatment corresponding to the degreasing step. The first temperature of the primary heating is a temperature at which the organic components are burned off and lower than the melting point of metallic silicon, and is set according to the type of the organic components contained in the laminate 24. By the primary heating, the organic components contained in the laminate 24 are burned off, and the laminate 24 becomes porous. At this time, since the temperature (first temperature) in the container 40 is lower than the melting point of the metal silicon, the metal silicon 42 contained in the container 40 is maintained in a solid state.

The first temperature is preferably, for example, a temperature of 400 ° C. or more and 1400 ° C. or less, and more preferably a temperature of 450 ° C. or more and 1000 ° C. or less. The first temperature can be a range in which the above upper and lower limits are arbitrarily combined, and can be a range in which an intermediate value between the above upper and lower limits is arbitrarily combined. By setting the first temperature within the above temperature range, it is possible to more reliably burn off the organic components contained in the laminate 24 while suppressing the melting of the metal silicon 42.

Primary heating is preferably performed until the organic components contained in the laminate 24 are completely removed. For example, by a preliminary test, a heating time for forming a porous body from which organic components contained in the laminate 24 have been removed is measured in advance, and the temperature in the container 40 is set to the first temperature with the elapse of the heating time. To the second temperature.

Secondary heating is a heat treatment corresponding to the impregnation step. The second temperature of the secondary heating is set to be equal to or higher than the melting point of metallic silicon. By the secondary heating, the metal silicon 42 contained in the container 40 is melted. Then, the molten metal silicon enters the gaps of the silicon carbide particles constituting the partition wall of the porous body through the support 41 made of a porous material by the capillary phenomenon, and the gaps are impregnated with the metal silicon 42. At this time, the boundary portion between the heat medium flowing portion and the gas flowing portion in the porous body is also impregnated with the metallic silicon 42 so that the boundary portion between the heat medium flowing portion and the gas flowing portion disappears.

Thereby, the metal exchanger 42 is impregnated in the gaps between the silicon carbide particles constituting the partition wall, and the heat exchanger 10 in which the plurality of heat medium circulating portions and the gas circulating portions are integrated is obtained.
The second temperature is preferably, for example, a temperature of 1420 ° C. or higher. By setting the second temperature in the above temperature range, it is possible to more reliably impregnate the metal silicon.

{Circle around (2)} The second temperature is, for example, preferably 2000 ° C. or lower, and more preferably 1900 ° C. or lower. By setting the second temperature within the above-mentioned temperature range, the production cost can be suppressed in terms of facilities and energy. Further, the thermal expansion of the porous body is suppressed, and damage due to the thermal expansion hardly occurs.

{Circle around (2)} The second temperature is preferably lower than the sintering temperature of silicon carbide contained in the mixture used in the molding step (for example, 2000 ° C. or lower). By setting the second temperature within the above-mentioned temperature range, the obtained heat exchanger 10 is in a non-sintered state in which most of the constituent silicon carbide particles are not sintered but exist independently. Become. This unsintered state has a high Young's modulus and is hardly deformed, and is useful as a heat exchanger.

The secondary heating is preferably performed until the metal silicon is sufficiently impregnated into the gaps between the silicon carbide particles constituting each wall of the porous body. For example, when the amount of the metal silicon 42 contained in the container 40 is an amount corresponding to the sum of the pore volume of the porous body and the pore volume of the support 41, all the metal silicon 42 is impregnated. Thus, it can be determined that the metal silicon has been sufficiently impregnated.

(4) After the secondary heating, the temperature in the vessel 40 is lowered, the heat exchanger 10 is taken out of the vessel 40, and the support 41 integrated with the lower surface of the heat exchanger 10 is separated. Thereby, the heat exchanger 10 is obtained.

Through the above-described impregnation step, a plurality of gas flow paths R1, a plurality of heat medium flow paths R2, and partition walls that partition the gas flow paths R1 and the heat medium flow paths R2 are provided. The heat exchanger 10 in which heat exchange is performed between the flowing gas and the liquid heat medium flowing through the heat medium flow passage R2 via the partition wall can be obtained.

Next, the operation and effect of the present embodiment will be described.
(1) The molding step is a sheet-like portion in which a gas flow path is formed in the molded body, and a plurality of protrusions scattered in a gas flow direction and a direction intersecting the flow direction are provided on the surface. It has a first molding step of molding the first molded body. In addition, the method includes a second forming step of forming a second formed body having a portion for forming a heat medium passage in the formed body, and a laminating step of stacking the first formed body and the second formed body.

By forming a plurality of protrusions scattered in the gas flow direction and a direction intersecting the flow direction on the first molded body, the gas flowing through the gas flow portion has a curved line between the plurality of protrusions. Distribute regularly. This makes it difficult to form a boundary layer that hinders the transfer of heat formed between the gas and the partition wall that forms the gas flow passage. Heat transport can be facilitated. Therefore, the heat exchange efficiency can be improved.

(2) In the laminating step, the tip of the projection of the first molded body is brought into contact with the first molded body or the second molded body superimposed on the first molded body. Via the convex portion, heat conduction between the first molded body provided with the convex portion and another first molded body or second molded body laminated on the first molded body can be promoted. . Therefore, the heat exchange efficiency can be improved.

(3) In the first forming step, the convex portions are formed by press forming. By forming the protrusions by press molding, it becomes easy to make the protrusions finer or to form the protrusions in a dense state.

(4) Side walls are provided at a pair of opposite ends of the first formed body on which the convex portions are formed, and the side walls are formed by press molding. Therefore, since the convex portion and the side wall can be formed at the same time, the heat exchanger can be manufactured efficiently.

(5) The projection is formed to have a tapered shape. Therefore, the flow resistance of the gas in the convex portion can be reduced.
This embodiment can be implemented with the following modifications. Further, the configuration of the above-described embodiment and the configuration shown in the following modified examples can be appropriately combined and implemented.

The first fluid flowing through the first flow passage is not limited to gas. The second fluid flowing through the second flow passage is not limited to the heat medium. The first fluid may be a heat carrier and the second fluid may be a gas. Both the first fluid and the second fluid may be gas or both may be heat medium.

The fluid flowing through the first flow passage and the second flow passage is not limited to the first fluid and the second fluid. For example, the second fluid and a third fluid different from the second fluid may flow through the second flow passage.

· The lamination form of the gas circulation part and the heat medium circulation part is not limited to the mode in which three gas circulation parts and one heat medium circulation part are alternately laminated. The lamination form of the gas circulation section and the heat medium circulation section can be appropriately selected.

In the present embodiment, the heat medium inlet is formed on one end side in the width direction DX of the heat medium flowing portion, and the heat medium outlet is formed on the other end side in the width direction DX. However, the present invention is not limited to this mode. . An outlet for the heat medium may be formed at one end of the width direction DX, and an inlet for the heat medium may be formed at the other end of the width DX. Similarly, the position of the inflow port and the outflow port of the gas flow section may be reversed.

It is preferable that the convex portion 25 has a tapered shape protruding in a curved shape as shown in FIGS. For example, in the example shown in FIG. 3, the fluid can flow through the gap between the two convex portions 25 adjacent in the width direction DX, but the distance between the two convex portions 25 adjacent in the width direction DX, that is, The width of the gap continuously changes in the front-rear direction DY due to the outer surface of the projection 25 having a curved shape in plan view. The resistance of the plurality of protrusions 25 to the fluid is not constant in the front-rear direction DY, and increases and / or decreases, for example, continuously. This is advantageous for causing non-uniformity of the fluid velocity in the front-rear direction DY, and is advantageous for making it difficult for the fluid flow to be in a rectified state. In addition, as is apparent from FIG. 5, the distance between the two convex portions 25 adjacent in the width direction DX, that is, the width of the gap continuously changes in the vertical direction DZ due to the tapered shape of the convex portions 25. The resistance of the plurality of protrusions 25 to the fluid is not constant in the vertical direction DZ, and increases and / or decreases, for example, continuously. This is advantageous for causing non-uniformity of the fluid velocity in the vertical direction DZ, and is advantageous for making it difficult for the fluid flow to be in a rectified state. However, the shape of the projection is not limited to the shape of the present embodiment. For example, a shape in which the vertical cross section of the convex portion is tapered linearly, such as a trapezoidal shape, may be used. The convex portion having such a shape is advantageous in causing non-uniformity in the fluid velocity at least in the vertical direction DZ, and is advantageous in making it difficult for the fluid flow to be in a rectified state. The convex portion does not need to have a tapered shape, and may have a columnar shape or a prismatic shape. The convex portion having such a shape is advantageous in causing non-uniformity of the fluid velocity at least in the front-rear direction DY, and is advantageous in making it difficult for the fluid flow to be in a rectified state.

(4) The tip of the convex portion does not have to be in contact with the lower surface of another gas circulation portion or the heat medium circulation portion that is overlapped with the gas circulation portion. That is, the height of the convex portion may be lower than the height of the side wall of the gas flow portion.

As shown in FIG. 10, the cross-sectional shape of the convex portion 25 of the present embodiment is configured such that the lower surface side of the bottom wall 21 is a flat surface, but is not limited to this mode. In the pressing step, instead of using a flat plate-shaped mold below the rectangular plate-shaped molded body, by using a mold protruding upward, for example, as shown in FIG. A convex portion 25 having a concave portion 26 formed on the side may be formed. By forming the concave portion 26 on the lower surface side of the bottom wall 21, the surface area on the lower surface side can be increased.

-As shown in Drawing 12, convex part 25 may be provided in both the upper surface side and the lower surface side of bottom wall 21 of gas circulation part 20.
-The method of forming the convex portion is not limited to press molding. For example, only the convex portion may be separately molded and joined to the bottom wall of the first molded body, or the first molded body may be injection molded.

· The arrangement of the protrusions is not limited to the arrangement of the present embodiment. In other words, the configuration is not limited to the configuration in which the plurality of protrusions have the protrusion rows arranged at equal intervals along the width direction DX, and the plurality of protrusion rows are arranged at equal intervals along the front-rear direction DY. . As long as the plurality of protrusions are scattered in the gas flow direction and the direction intersecting the flow direction, for example, a configuration in which the protrusions are arranged irregularly (randomly) may be employed.

In the present embodiment, the side wall of the first molded body is formed by press molding, but is not limited to this mode. For example, after the projections are formed by press molding, the separately formed side walls may be joined. Alternatively, after extrusion molding in a state where the bottom wall and the side wall are integrated, only the projection may be formed by press molding.

In the present embodiment, the side wall of the second molded body is formed by press molding, but is not limited to this mode. For example, the second molded body may be extruded with the bottom wall and the side wall integrated. After separately forming the bottom wall and the side wall, both may be joined.

(4) The heat medium circulating portion is not limited to a mode in which two through holes forming the heat medium flow passage are formed. By providing a plurality of standing walls instead of the central wall provided at an intermediate position of each side wall, three or more through holes may be formed. The central wall may be omitted and one through hole may be formed.

The heat medium circulating section is not limited to the form formed using the sheet-shaped second molded body. A honeycomb structure in which a plurality of cells are arranged may be used as the heat medium circulating unit.
A baking step may be inserted between the degreasing step and the impregnation step. By firing the degreased porous body, it is possible to improve the strength of the porous body and prevent the porous body from being damaged in the impregnation step. In the firing step, the temperature can be 2100 ° C. to 2250 ° C., and the holding time can be 1 to 5 hours.

R1: first flow path (gas flow path), R2: second flow path (heat medium flow path), 10: heat exchanger, 18: first molded body, 19: second molded body.

Claims

A plurality of first flow paths, a plurality of second flow paths, a partition wall that partitions the first flow path and the second flow path, a first fluid flowing through the first flow path, A method for producing a silicon carbide heat exchanger in which heat exchange is performed between the second fluid flowing through a second flow passage and the second fluid through the partition wall,
Using a raw material composition containing silicon carbide particles, a forming step of forming a formed body having the first flow path and the second flow path;
A degreasing step of degreasing the molded body to produce a porous body,
Impregnation step of impregnating the porous body with metal silicon,
The molding step includes:
A sheet-like portion having a surface on which a plurality of protrusions scattered in a flow direction of the first fluid and a direction intersecting the flow direction are provided on a surface of the molded body, where the first flow passage is formed. A first molding step of molding one molded body;
A second forming step of forming a second formed body having a portion forming the second flow passage in the formed body;
A method for manufacturing a heat exchanger, comprising: a laminating step of laminating the first molded body and the second molded body.
2. The heat exchange according to claim 1, wherein, in the laminating step, a tip of the protrusion of the first molded body is brought into contact with the first molded body or the second molded body superimposed on the first molded body. Method of manufacturing the vessel.
The method according to claim 1 or 2, wherein in the first forming step, the protrusion is formed by press forming.
Side walls are provided at a pair of opposite ends of the first molded body on which the convex portions are formed,
The method for manufacturing a heat exchanger according to claim 1, wherein the side wall is formed by press molding.
方法 The method for manufacturing a heat exchanger according to any one of claims 1 to 4, wherein the convex portion is formed to have a prismatic or elliptical columnar shape.