JP2011149671A - Ebullient cooling type heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress generation of local burnout in an ebullient cooling type heat exchanger which is arranged with a cooled fluid side fin in a cooled fluid passage. <P>SOLUTION: A coolant side fin 31 is arranged in an area in a coolant passage 24 corresponding to an upstream part 21a of the cooled fluid passage 21, which is also an area to be a downstream part 24b of the coolant passage 24. Part of a partition wall 19 where the coolant side fin 31 is brazed with brazing material is polymerized on part of the partition wall 19 where the cooled fluid side fin 30 is brazed with the brazing material. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a boiling cooling heat exchanger.

  In general, a heat exchanger of a boiling cooling device has a cooled fluid passage through which a fluid to be cooled flows and a refrigerant passage through which a liquid refrigerant that cools the cooled fluid flows, and the cooled fluid passage and the refrigerant passage have partition walls. Heat exchange is possible. In the heat exchanger, the liquid refrigerant flowing through the refrigerant passage is heated by removing heat from the partition wall heated by the fluid to be cooled, and when the temperature of the heat transfer surface in the partition wall exceeds the saturation temperature of the liquid refrigerant, Nucleate boiling, in which bubbles are repeatedly generated and separated, starts. The to-be-cooled fluid flowing through the to-be-cooled fluid passage is cooled using the latent heat of vaporization by boiling due to the nucleate boiling. A heat exchanger of such a boiling cooling device is disclosed in Patent Document 1, for example.

  The exhaust gas heat exchanger of Patent Document 1 is a plate fin type exhaust gas heat exchanger. In this heat exchanger for exhaust gas, a required number of stages of fluid passages are formed by sandwiching corrugated fins to increase the heat transfer area between two tube plates (partitions) closed on both sides with a pair of spacer bars. It becomes. In the exhaust gas heat exchanger, the high-temperature fluid (cooled fluid) and the low-temperature fluid (liquid refrigerant) flow into the separate fluid passages from the adjacent side surfaces, and the high-temperature fluid and the low-temperature fluid connect the tube plate and the corrugated fin. The heat is exchanged through the water and boiling cooling is performed.

Japanese Utility Model Publication No. 3-79070

  However, in the exhaust gas heat exchanger of Patent Document 1, the heat flux at the contact portion with the corrugated fin in the tube plate locally increases in the fluid passage through which the high-temperature fluid flows. Then, in the fluid passage through which the low-temperature fluid flows, at the position corresponding to the contact portion where the heat flux is locally increased, the low-temperature fluid boils intensely, and the tube plate is shifted to film boiling covered with the bubble film. Burnout is likely to occur. When burnout occurs, drying occurs at a position corresponding to the contact portion in the fluid passage through which the low-temperature fluid flows, and the cooling performance of the heat exchanger decreases.

  Further, in the exhaust gas heat exchanger of Patent Document 1, the corrugated fins are disposed in the fluid passage through which the low-temperature fluid flows, but there is no mention of suppressing the occurrence of burnout.

  An object of the present invention is to suppress the occurrence of local burnout in a boiling cooling heat exchanger in which a cooled fluid side fin is disposed in a cooled fluid passage.

  In order to achieve the above object, the invention according to claim 1 is a partition wall that partitions a cooled fluid passage through which a fluid to be cooled flows and a refrigerant passage through which a refrigerant that cools the cooled fluid flows, and the cooled fluid. A boiling-cooling type heat exchanger having a fluid-side fin to be cooled disposed in the passage, wherein the heat passage in the refrigerant passage is determined based on a relationship between a heat flux in the partition and a critical heat flux of the refrigerant. The coolant side fin is disposed in the region, the cooled fluid side fin and the coolant side fin have a standing portion, and the standing portion of the cooled fluid side fin in the region in the coolant passage. The gist is that the refrigerant side fin is disposed at a position corresponding to the partition wall side end portion in such a manner that the partition wall side end portion of the standing portion of the refrigerant side fin is positioned.

  According to the present invention, the partition wall side end portion of the refrigerant side fin standing portion is positioned relative to the position corresponding to the partition wall side end portion of the standing portion of the cooled fluid side fin where the heat flux is likely to rise locally. Thus, the refrigerant side fin is disposed in the refrigerant passage. For this reason, in the partition wall, the heat of the portion in contact with the partition wall side end portion of the standing portion of the cooled fluid side fin is distributed to the refrigerant side fin, and in the partition wall, the partition wall side end in the standing portion of the cooled fluid side fin It is possible to suppress an increase in the heat flux at the part that contacts the part. Therefore, in the partition wall, it is possible to suppress that the heat flux of the portion that contacts the partition wall side end portion of the standing part of the cooled fluid side fin is greater than or equal to the critical heat flux of the refrigerant. In the boiling cooling type heat exchanger in which the cooled fluid side fins are arranged in the passage, it is possible to suppress the occurrence of local burnout.

  According to a second aspect of the present invention, in the first aspect of the present invention, the refrigerant side fin is disposed in a region in the refrigerant passage corresponding to an upstream portion in the flow direction of the cooled fluid in the cooled fluid passage. The gist is that it is provided.

  In the upstream portion of the fluid passage to be cooled, the fluid to be cooled has a high temperature since the fluid to be cooled has just flowed into the fluid passage to be cooled. For this reason, in the partition wall, the heat flux at the portion in contact with the partition wall side end portion of the standing portion of the cooled fluid side fin in the upstream portion of the cooled fluid passage is the fluid to be cooled in the downstream portion of the cooled fluid passage. It tends to rise as compared with the heat flux at the portion in contact with the partition wall side end portion in the standing portion of the side fin.

  In the present invention, the refrigerant corresponding to the upstream portion in the flow direction of the cooled fluid in the cooled fluid passage where the heat flux at the portion in contact with the partition wall side end portion of the standing portion of the cooled fluid side fin is likely to rise locally Refrigerant-side fins are disposed in the region within the passage. For this reason, in the partition wall, the heat of the portion in contact with the partition wall side end portion of the standing portion of the cooled fluid side fin is distributed to the refrigerant side fin, and the standing of the cooled fluid side fin in the upstream portion of the cooled fluid passageway. It is possible to suppress an increase in the heat flux at a portion in contact with the partition wall side end portion in the installation portion. Therefore, it can suppress that the heat flux of the site | part which contacts the partition wall side edge part in the standing part of the to-be-cooled fluid side fin becomes more than the limit heat flux of a refrigerant | coolant in the upstream part of a to-be-cooled fluid channel | path.

The gist of the invention according to claim 3 is that, in the invention according to claim 1, a refrigerant-side fin is disposed in a downstream portion of the refrigerant passage in the flow direction of the refrigerant.
The refrigerant flowing in the refrigerant passage is heated and boiled by heat exchange with the fluid to be cooled while flowing from the upstream portion to the downstream portion of the refrigerant passage, and bubbles are mixed in the refrigerant. The bubbles increase or increase in number toward the downstream portion of the refrigerant passage, so that the critical heat flux of the refrigerant in the downstream portion of the refrigerant passage is greater than the critical heat flux of the refrigerant in the upstream portion of the refrigerant passage. Becomes smaller.

  In the present invention, the refrigerant-side fin is disposed in the downstream portion of the refrigerant passage where the critical heat flux of the refrigerant becomes small. For this reason, the portion in contact with the partition wall side end portion of the standing portion of the cooled fluid side fin disposed in the region in the cooled fluid passage corresponding to the downstream portion of the coolant passage where the critical heat flux of the refrigerant becomes small Heat is dispersed in the refrigerant side fins, and the heat flux can be suppressed. Therefore, the heat flow of the portion in contact with the partition wall side end portion in the standing portion of the cooled fluid side fin disposed in the region in the cooled fluid passage corresponding to the downstream portion of the coolant passage where the critical heat flux of the coolant becomes small It can suppress that a bundle becomes more than the limit heat flux of a refrigerant. As a result, it is possible to suppress the occurrence of burnout even in the partition wall in the downstream portion of the refrigerant passage where the critical heat flux of the refrigerant becomes small.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the flow direction of the fluid to be cooled and the flow direction of the refrigerant intersect with each other. A fluid passage and the refrigerant passage are arranged side by side, and a refrigerant side fin is arranged in a region in the refrigerant passage corresponding to an upstream portion of the fluid passage to be cooled and a downstream portion of the refrigerant passage. The gist is that it is provided.

  Since the fluid to be cooled is high in the upstream portion of the fluid passage to be cooled, the heat flux at the portion of the partition wall that contacts the end portion on the partition wall side in the standing portion of the fin on the fluid fluid side in the upstream portion of the fluid passage to be cooled. Since the number of bubbles is large in the downstream portion of the refrigerant passage, the critical heat flux of the refrigerant in the downstream portion of the refrigerant passage is reduced.

  In the present invention, the refrigerant-side fins are disposed in the region in the refrigerant passage corresponding to the upstream portion of the fluid passage and the downstream portion of the refrigerant passage. The heat of the part in contact with the partition wall side end in the standing part of the side fin is dispersed throughout the refrigerant side fin, and the heat flux can be suppressed. As a result, even if the critical heat flux of the refrigerant is reduced, the heat flux of the part of the partition that contacts the partition side end of the standing part of the cooled fluid side fin is greater than or equal to the critical heat flux of the refrigerant. Can be suppressed.

  A fifth aspect of the present invention is the refrigerant passage according to any one of the first to fourth aspects, wherein the refrigerant passage is determined based on a relationship between a heat flux in the partition and a critical heat flux of the refrigerant. The inner region is a region in the refrigerant passage where the heat flux in the partition wall is larger than the critical heat flux of the refrigerant.

  According to the present invention, in the partition wall, it is possible to suppress that the heat flux of the portion in contact with the partition wall side end portion in the standing portion of the cooled fluid side fin becomes equal to or higher than the limit heat flux of the refrigerant, and as a result. In the boiling cooling type heat exchanger in which the cooled fluid side fins are arranged in the cooled fluid passage, the occurrence of local burnout can be suppressed.

  According to the present invention, in the boiling cooling heat exchanger in which the fluid to be cooled side fins are disposed in the fluid to be cooled passage, it is possible to suppress the occurrence of local burnout.

The schematic perspective view of the boiling cooling type heat exchanger in embodiment. The disassembled perspective view of the heat exchange part in a heat exchanger. The fragmentary longitudinal cross-sectional view of the to-be-cooled fluid side fin and the refrigerant | coolant side fin. The graph which shows the relationship in the distribution direction of a to-be-cooled fluid channel | path, and a heat flux. The disassembled perspective view which shows a part of heat exchange part in another embodiment. The fragmentary longitudinal cross-sectional view of the to-be-cooled fluid side fin and refrigerant | coolant side fin in another embodiment. The schematic perspective view of the boiling-cooling type heat exchanger in another embodiment. The disassembled perspective view which shows a part of heat exchange part in another embodiment. The disassembled perspective view which shows a part of heat exchange part in another embodiment. The disassembled perspective view which shows a part of heat exchange part in another embodiment. The fragmentary longitudinal cross-sectional view of the to-be-cooled fluid side fin and refrigerant | coolant side fin in another embodiment.

  Hereinafter, the present invention is a boiling cooling type heat exchanger (hereinafter, simply referred to as “heat exchanger”) of an EGR gas boiling cooling device (EGR cooler) in an exhaust gas recirculation (EGR) of a vehicle. 1 to 4 will be described with reference to FIGS. The heat exchanger 11 of the exhaust gas recirculation device performs heat exchange between the EGR gas as a fluid to be cooled and water (liquid refrigerant) as a refrigerant, and boiles part of the water to cool the EGR gas. In the following description, the terms “front-rear direction”, “vertical direction”, and “left-right direction” refer to “front-rear direction”, “vertical direction”, and “left-right direction” indicated by arrows in FIG. 1 unless otherwise specified. Direction ".

  As shown in FIG. 1, a heat exchange section 12 is accommodated in a substantially square box-shaped housing 11 a that forms the outline of the heat exchanger 11. In the housing 11a, a cooled fluid introduction part 14 is provided on the front (one side) side of the heat exchange part 12, and a cooled fluid discharge part 15 is provided on the rear side (the other side) of the heat exchange part 12. It has been.

  The front end surface (one end surface) of the housing 11a is connected to an introduction pipe 16 for introducing EGR gas into the fluid-to-be-cooled fluid introducing portion 14, and the rear end surface (other end surface) of the housing 11a is supplied with EGR gas. A discharge pipe 17 for discharging from the cooled fluid discharge unit 15 is connected. The heat exchanger 11 is used with the introduction pipe 16 connected to the EGR passage inlet side and the discharge pipe 17 connected to the EGR passage outlet side.

  One end 22a of a refrigerant introduction pipe 22 for introducing water into the heat exchanging portion 12 in the housing 11a is connected to the left end surface of the housing 11a (end surface sandwiched between one end surface and the other end surface). In addition, one end 23a of a refrigerant discharge pipe 23 for discharging water from the heat exchange unit 12 is connected to the right end surface of the housing 11a (an end surface sandwiched between one end surface and the other end surface).

  As shown in FIG. 2, the heat exchanging portion 12 is formed by sandwiching a cooled fluid side fin 30 between two flat partition walls 19 closed on both sides by a pair of spacer bars 20 (this embodiment). In the embodiment, three passage partition bodies 18 and a plurality of refrigerant side fins 31 sandwiched between the passage partition bodies 18 are stacked. Further, as shown in FIG. 1, the heat exchange section 12 includes a front wall 13 a joined to the front (one) opening end of each passage partition 18 and a rear wall joined to the rear (other) opening end. 13b.

  Each passage partition 18 is disposed such that the front opening is located on the cooled fluid introduction part 14 side and the rear opening is located on the cooled fluid discharge part 15 side. In the front wall 13a, a long hole 13e that allows the fluid introduction part 14 to be cooled and the front opening of each passage partition body 18 to communicate with each other is formed in a portion corresponding to each passage partition body 18. In addition, a long hole (not shown) for communicating the fluid discharge portion 15 to be cooled and the rear opening of each passage partition body 18 is formed in a portion corresponding to each passage partition body 18 in the rear wall 13b. Yes.

  The EGR gas that has flowed into the cooled fluid introducing portion 14 from the introduction pipe 16 flows into the passage partition bodies 18 from the front opening through the long hole 13e of the front wall 13a, and from the rear opening. It flows out to the cooled fluid discharge part 15 through the long hole of the rear wall 13b, and flows into the EGR passage outlet side through the discharge pipe 17. Therefore, as shown in FIG. 2, a cooled fluid passage 21 through which the EGR gas flows is formed by the space in the passage partition body 18.

  In the fluid passage 21 to be cooled, the opening in front of the passage partition body 18 is used as an EGR gas inlet, and the inlet side of the passage partition body 18 is cooled in the EGR gas flow direction (direction of arrow X1 shown in FIG. 2). The upstream portion 21 a of the fluid passage 21 is used. Further, in the cooled fluid passage 21, the opening behind the passage partition body 18 serves as an outlet, and the outlet side of the passage partition body 18 serves as a downstream portion 21 b of the cooled fluid passage 21 in the EGR gas flow direction. Here, the “upstream portion 21a of the fluid passage 21 to be cooled” in the present embodiment refers to a region from the central portion in the flow direction in the fluid passage 21 to the inlet side. The “21st downstream portion 21b” refers to a region from the central portion in the flow direction in the fluid passage 21 to the outlet side.

  In the heat exchanging unit 12, the refrigerant side fins 31 are sandwiched between the partition walls 19 facing each other between the passage partition bodies 18, and a coolant passage 24 is defined between the partition walls 19. As shown in FIG. 1, the refrigerant passage 24 has a pair of front and rear openings opposed to each other by a front wall 13a and a rear wall 13b, and a pair of left and right side surfaces orthogonal to the front wall 13a and the rear wall 13b. It is open.

  One end 22 a of the refrigerant introduction pipe 22 is disposed opposite to the left (one) opening in the refrigerant passage 24, and one end 23 a of the refrigerant discharge pipe 23 is opposed to the right (other) opening in the refrigerant passage 24. Opposed. The other end of the refrigerant introduction pipe 22 is connected to one end of a water circulation pipe (not shown), and the other end of the refrigerant discharge pipe 23 is connected to the other end of the circulation pipe. Then, water is introduced into the refrigerant passage 24 from one end 22a of the refrigerant introduction pipe 22, and the water that has passed through the refrigerant passage 24 flows out to the one end 23a of the refrigerant discharge pipe 23 and is returned to the circulation pipe.

  In the refrigerant passage 24, the left opening facing the one end 22a of the refrigerant introduction pipe 22 is used as the inlet of the refrigerant passage 24, and the inlet side of the refrigerant passage 24 is the water flow direction (the direction of the arrow X2 shown in FIG. 2). The upstream portion 24a of the refrigerant passage 24 in FIG. Further, in the refrigerant passage 24, the right opening facing the one end 23a of the refrigerant discharge pipe 23 is used as the outlet of the refrigerant passage 24, and the outlet side of the refrigerant passage 24 is the downstream portion 24b of the refrigerant passage 24 in the water flow direction. And Here, the “upstream portion 24a of the refrigerant passage 24” in the present embodiment refers to a region from the central portion in the flow direction of the refrigerant passage 24 to the inlet side, and “the downstream portion 24b of the refrigerant passage 24”. The term “region” refers to a region from the central portion in the flow direction in the refrigerant passage 24 to the outlet side.

  That is, the upstream portion 24a of the refrigerant passage 24 is provided on one end side in the direction orthogonal to the flow direction of the EGR gas, and the downstream portion 24b of the refrigerant passage 24 is the other end side in the direction orthogonal to the flow direction of the EGR gas. It is supposed to be located in. Further, the cooled fluid passage 21 and the refrigerant passage 24 are partitioned by the partition wall 19 forming the passage partition body 18. The cooled fluid passage 21 and the refrigerant passage 24 are juxtaposed so that the flow direction of the EGR gas in the cooled fluid passage 21 and the flow direction of water in the refrigerant passage 24 are orthogonal (intersect).

  As shown in FIG. 2, the to-be-cooled fluid side fin 30 is a straight fin formed by bending a plate having the same width as the to-be-cooled fluid passage 21 into a wave shape along a direction orthogonal to the flow direction of the EGR gas. And is disposed over the entire region in the passage partition 18 (region from the upstream portion to the downstream portion in the flow direction). As shown in FIG. 3, the to-be-cooled fluid side fin 30 includes a flat surface 30 a that contacts the wall surface 19 a of the partition wall 19, and a standing portion 30 c that extends in the vertical direction and connects the flat surfaces 30 a to each other.

  And as for the passage division body 18, the space | interval of the partition walls 19 is the height of the standing part 30c. In addition, the corners 30b of the cooled fluid-side fins 30 positioned at both ends of the flat surface 30a are formed in a curved shape, and the brazing material R1 is poured into the corners 30b and the brazing material R1 is melted. The cooled fluid side fin 30 is brazed to the partition wall 19. Therefore, the partition 19 side end portion of the standing portion 30c of the cooled fluid-side fin 30 is formed by the portion brazed by the brazing material R1, and the cooled fluid-side fin 30 and the partition 19 are flat surfaces. Heat can be transferred through the portion brazed by 30a and the brazing material R1.

  A refrigerant-side fin 31 is disposed in a region in the refrigerant passage 24 corresponding to the upstream portion 21 a of the fluid passage 21 to be cooled and a downstream portion 24 b of the refrigerant passage 24. The refrigerant-side fins 31 are straight fins formed by bending a plate having a right triangle shape in a top view into a wave shape along the direction of water flow. As shown in FIG. 3, the refrigerant side fin 31 includes a flat surface 31 a that contacts the wall surface 19 a of the partition wall 19, and a standing portion 31 c that extends in the vertical direction and connects the flat surfaces 31 a to each other.

  And the refrigerant | coolant channel | path 24 has the space | interval of the partition walls 19 the height of the standing part 31c. In addition, the corner portions 31b of the refrigerant-side fins 31 positioned at both ends of the flat surface 31a are formed in a curved shape, and the brazing filler metal R2 is poured into the corner portions 31b and the brazing filler metal R2 is melted, so that the refrigerant side The fin 31 is brazed to the partition wall 19. Therefore, the partition 19 side end portion of the standing portion 31c of the refrigerant side fin 31 is formed by the portion brazed by the brazing material R2, and the refrigerant side fin 31 and the partition wall 19 include the flat surface 31a and the brazing material. Heat can be transferred through the part brazed by R2.

  The to-be-cooled fluid-side fins 30 and the refrigerant-side fins 31 are formed to have the same thickness, and the intervals (pitches) between the irregularities in the to-be-cooled fluid-side fins 30 and the refrigerant-side fins 31 are the same. And the to-be-cooled fluid side fin 30 and the refrigerant | coolant side fin 31 superpose | polymerize the site | part brazed with the brazing material R1 with respect to the partition 19, and the site | part brazed with the brazing material R2 with respect to the partition 19. Further, they are disposed in the cooled fluid passage 21 and the refrigerant passage 24, respectively.

Next, the effect | action in the heat exchanger 11 of the said structure is demonstrated.
When the vehicle is operated, EGR gas, which is part of the exhaust gas of the internal combustion engine, flows into the EGR passage inlet side, and the cooled fluid passage through the introduction pipe 16, the cooled fluid introduction portion 14, and the long hole 13e. 21. The EGR gas introduced into the cooled fluid passage 21 flows from the inlet to the outlet of the cooled fluid passage 21.

  Here, the EGR gas is high in temperature immediately after flowing into the cooled fluid passage 21 in the upstream portion 21a of the cooled fluid passage 21, and is cooled by heat exchange with water toward the downstream portion 21b. It becomes low temperature. Therefore, in the partition wall 19, the heat flux of the portion brazed with the brazing material R <b> 1 to the partition wall 19 in the upstream portion 21 a of the cooled fluid passage 21 is relative to the partition wall 19 in the downstream portion 21 b of the cooled fluid passage 21. Compared to the heat flux of the part brazed by the soldering material R1, it tends to rise.

  On the other hand, water is forcibly circulated in the circulation line by driving a pump (not shown) disposed on the circulation line, and is introduced into the refrigerant path 24 via the refrigerant introduction pipe 22. The water introduced into the refrigerant passage 24 flows from the inlet of the refrigerant passage 24 toward the outlet.

  Here, the water flowing in the refrigerant passage 24 partially boiled by heat exchange with the EGR gas while flowing from the upstream portion 24a to the downstream portion 24b of the refrigerant passage 24, and the water and bubbles are mixed. . The water moves in the refrigerant passage 24 toward the outlet of the refrigerant passage 24 while being mixed with bubbles. The bubbles merge with each other and increase in number as they go to the downstream portion 24b of the refrigerant passage 24. Therefore, the critical heat flux of the refrigerant in the downstream portion 24b of the refrigerant passage 24 is the upstream portion of the refrigerant passage 24. It becomes smaller than the limit heat flux of the refrigerant in 24a.

  However, in the present embodiment, the refrigerant-side fins 31 are disposed in the region in the refrigerant passage 24 corresponding to the upstream portion 21 a of the fluid passage 21 to be cooled and the downstream portion 24 b of the refrigerant passage 24. In the partition wall 19, the part brazed to the partition wall 19 by the brazing material R1 and the part brazed to the partition wall 19 by the brazing material R2 are polymerized. Therefore, the heat of the portion where the cooled fluid side fin 30 is brazed to the partition wall 19 by the brazing material R1 moves to the portion where the refrigerant side fin 31 is brazed to the partition wall 19 by the brazing material R2. The refrigerant side fins 31 are dispersed throughout. As a result, it is possible to suppress an increase in the heat flux of the portion where the cooled fluid side fin 30 is brazed to the partition wall 19 by the brazing material R1.

  Here, the graph of FIG. 4 shows the relationship between the position in the flow direction of the fluid passage 21 to be cooled and the heat flux in the section AA shown in FIG. The graph of FIG. 4 shows the position of the fluid passage 21 to be cooled on the horizontal axis and the heat flux on the vertical axis. In the graph of FIG. 4, the solid line indicates the heat flux of the portion where the cooled fluid-side fin 30 in the partition wall 19 when the refrigerant-side fin 31 is disposed is brazed by the brazing material R1. Further, the heat flux at the portion where the cooled fluid-side fin 30 in the partition wall 19 is brazed by the brazing material R2 when the refrigerant-side fin 31 is not disposed in the refrigerant passage 24 is indicated by a two-dot chain line for comparison. Yes. Furthermore, the critical heat flux of the refrigerant is indicated by a broken line.

  As shown in FIG. 4, when the refrigerant-side fins 31 are disposed in the refrigerant passage 24, the to-be-cooled fluid-side fins 30 in the partition wall 19 are brazed by the brazing material R1 as compared with the case where the refrigerant-side fins 31 are not disposed. The heat flux of the part made is suppressed. As a result, the heat flux at the portion of the partition wall 19 where the cooled fluid-side fins 30 are brazed by the brazing material R1 is suppressed to be greater than or equal to the critical heat flux of the refrigerant.

  When heat exchange between water and the EGR gas is performed via the partition wall 19, the water boils on the wall surface 19 a of the partition wall 19 to become steam, and the EGR gas that flows in the cooled fluid passage 21 using the boiling vaporization latent heat. Cool down. And the water which cooled EGR gas is discharged | emitted from the exit of the refrigerant path 24 to the circulation line via the refrigerant | coolant discharge piping 23, and the water discharged | emitted to the circulation line was shown on the circulation line The refrigerant is condensed by the refrigerant condensing unit and is supplied to the heat exchanger 11 again. The cooled EGR gas flows from the outlet of the fluid passage 21 to the EGR passage outlet side through the discharge pipe 17, and the EGR gas that flows into the EGR passage outlet side enters the intake system of the internal combustion engine. Refluxed.

In the above embodiment, the following effects can be obtained.
(1) The refrigerant side fins 31 are disposed in a region in the refrigerant passage 24 corresponding to the upstream portion 21a of the fluid passage 21 to be cooled and the downstream portion 24b of the refrigerant passage 24. The part brazed to the partition wall 19 with the brazing material R1 and the part brazed to the partition wall 19 with the brazing material R2 were polymerized. That is, the coolant side fins 30 in the partition wall 19 are brazed by the brazing material R1 so that the heat flux tends to rise locally, and the refrigerant side 24 has a region where the critical heat flux of the coolant is small. The fins 31 are disposed, and the portion of the partition wall 19 where the cooled fluid side fin 30 is brazed by the brazing material R1 is polymerized to the portion of the partition wall 19 where the refrigerant side fin 31 is brazed by the brazing material R2. . Therefore, the heat of the portion where the cooled fluid side fin 30 in the partition wall 19 is brazed by the brazing material R1 is dispersed throughout the refrigerant side fin 31, and the cooled fluid side fin 30 in the partition wall 19 is brazed by the brazing material R1. An increase in the heat flux at the formed part can be suppressed. As a result, it is possible to suppress the heat flux of the portion of the partition wall 19 where the cooled fluid-side fin 30 is brazed by the brazing material R1 from exceeding the limit heat flux of the refrigerant, and local burnout occurs. Can be suppressed.

  (2) The height of the standing portion 31 c in the refrigerant-side fin 31 is an interval between the partition walls 19 that define and form the refrigerant passage 24. Therefore, the passage partition body 18 in which the flat surface 31a of the refrigerant-side fin 31 forms the upper fluid passage 21 to be cooled with the refrigerant passage 24 interposed therebetween, by arranging only one refrigerant-side fin 31 in the refrigerant passage 24. Can contact both the wall surface 19a of the partition wall 19 and the wall surface 19a of the partition wall 19 in the passage partition 18 that forms the lower fluid passage 21 to be cooled. Therefore, the refrigerant-side fins are disposed so as to overlap with the joint portion between the cooled-fluid-side fins 30 and the partition walls 19 disposed in the upper-cooled fluid passage 21, and further the lower-cooled fluid passage 21. Compared with the case where another refrigerant-side fin is disposed so as to overlap with the joint portion between the cooled fluid-side fin 30 and the partition wall 19 disposed therein, it is possible to save the labor of manufacturing the heat exchanger 11. it can.

  (3) The refrigerant-side fins 31 are disposed in a region in the refrigerant passage 24 corresponding to the upstream portion 21 a of the fluid passage 21 to be cooled and the downstream portion 24 b of the refrigerant passage 24. Therefore, compared with the case where the refrigerant-side fins are provided in the entire area of the refrigerant passage 24, when water passes through the refrigerant passage 24, the water can smoothly pass through the refrigerant passage 24 without resistance.

In addition, you may change the said embodiment as follows.
In the embodiment, the refrigerant passage 24 has only one entrance, but the present invention is not limited to this. For example, as shown in FIG. 5, the inlet of the refrigerant passage 24 is provided at two ends on the both sides in the direction orthogonal to the EGR gas flow direction, and the outlet of the refrigerant passage 24 is arranged in a direction orthogonal to the EGR gas flow direction. It may be provided on the end side so that the flow direction of water flows in the direction of the arrow X3 shown in FIG. In the heat exchanger 11 configured as described above, when water flows into the refrigerant passage 24 from two inlets provided at both ends in a direction orthogonal to the flow direction of the EGR gas, the flow direction in both waters The central portion 24 c of the refrigerant passage 24 that hits the downstream side of the refrigerant corresponds to the downstream portion of the refrigerant passage 24. In this case, in the refrigerant passage 24, the refrigerant-side fins 31 are disposed in a region corresponding to the upstream portion 21 a of the fluid passage 21 to be cooled and the central portion 24 c of the refrigerant passage 24. According to this, the heat of the part where the cooled fluid side fin 30 in the partition wall 19 is brazed by the brazing material R1 moves to the part where the refrigerant side fin 31 in the partition wall 19 is brazed by the brazing material R2, Dispersed throughout the refrigerant-side fins 31. Therefore, it can suppress that the heat flux of the site | part where the to-be-cooled fluid side fin 30 in the partition 19 was brazed by the brazing | wax material R1 becomes more than the limit heat flux of a refrigerant | coolant.

  Further, for example, as shown in FIG. 6, a plurality of first refrigerant side fins 33 having a U-shaped cross-sectional view provided with a flat surface 33 a that contacts the wall surface 19 a of the upper partition wall 19 are disposed in the upper partition wall 19. In addition, a plurality of second refrigerant side fins 34 having a flat surface 34 a that contacts the wall surface 19 a of the lower partition wall 19 may be disposed on the lower partition wall 19. A gap S <b> 2 is formed between the tip of the standing portion 33 b extending in the height direction of the first refrigerant side fin 33 and the tip of the standing portion 34 b extending in the height direction of the second refrigerant side fin 34. Thus, the length of the height direction in the 1st refrigerant | coolant side fin 33 and the 2nd refrigerant | coolant side fin 34 is set. According to this, of the water that has flowed into the refrigerant passage 24 from the inlet of the refrigerant passage 24, the water that goes to the first refrigerant-side fin 33 and the second refrigerant-side fin 34 passes through the gap S2 in the refrigerant passage 24. Can flow toward the exit.

  In the embodiment, the one end 22 a of the refrigerant introduction pipe 22 is connected to the left and right (one) openings in the refrigerant passage 24, and the one end 23 a of the refrigerant discharge pipe 23 is the right (the other) opening in the refrigerant passage 24. However, this is not a limitation.

  For example, as shown in FIG. 7, in the housing 11 a, an introduction part 35 is provided on the front (one) side of the heat exchange part 12, and a discharge part on the rear (other) side of the heat exchange part 12 36 is provided. In the front wall 13 a, long holes 13 f that allow the introduction portion 35 to communicate with the refrigerant passages 24 are formed in portions corresponding to the refrigerant passages 24. On the other hand, in the rear wall 13 b, long holes (not shown) for communicating the discharge portion 36 and the refrigerant passages 24 are formed at portions corresponding to the refrigerant passages 24.

  A partition wall 13g that extends in a direction orthogonal to the end surface of the front wall 13a and connects the front wall 13a and the front end surface (one end surface) of the housing 11a extends in the vertical direction on the end surface of the front wall 13a on the introduction portion 35 side. A plurality of them are provided at predetermined intervals. The partition portion 13g divides the inside of the introduction portion 35 into a cooled fluid side space K1 corresponding to each cooled fluid passage 21 and a refrigerant side space K2 corresponding to each refrigerant passage 24.

  On the other hand, a partition wall 13h that extends in a direction orthogonal to the end surface of the rear wall 13b and that connects the rear wall 13b and the rear end surface (the other end surface) of the housing 11a is provided on the end surface of the rear wall 13b on the discharge portion 36 side. Are provided at predetermined intervals. The partition 13h divides the inside of the discharge section 36 into a cooled fluid side space K3 corresponding to each cooled fluid passage 21 and a refrigerant side space K4 corresponding to each refrigerant passage 24.

  Further, one end 16a of the introduction pipe 16 is connected to a portion corresponding to the cooled fluid side space K1 on the front end surface of the housing 11a, and at a portion corresponding to the cooled fluid side space K3 on the rear end surface of the housing 11a. The one end 17a of the discharge pipe 17 is connected. On the other hand, a portion corresponding to the refrigerant side space K2 on the left side surface of the introduction portion 35 is connected to one end 22a of the refrigerant introduction pipe 22 and a portion corresponding to the refrigerant side space K4 on the right side surface of the discharge portion 36. Is connected to one end 23a of the refrigerant discharge pipe 23.

  The EGR gas flowing from the introduction pipe 16 into the introduction portion 35 flows into the cooled fluid side space K1 from one end 16a of the introduction pipe 16 and passes through the cooled fluid passage 21 through the long hole 13e. Then, it flows into the cooled fluid side space K 3 and is discharged from the discharge pipe 17. On the other hand, the refrigerant flowing from the refrigerant introduction pipe 22 into the introduction portion 35 flows into the refrigerant side space K2 from one end 22a of the refrigerant introduction pipe 22, and passes through the refrigerant passage 24 through the long hole 13f. The refrigerant flows into the refrigerant side space K4 and is discharged from the refrigerant discharge pipe 23.

  By flowing the refrigerant in this way, the refrigerant can easily flow between the standing portions 31c of the refrigerant-side fins 31, and the cooled fluid-side fin 30 is brazed to the partition wall 19 by the brazing material R1. The heat of the part can be easily moved to the part where the refrigerant side fin 31 is brazed to the partition wall 19 by the brazing material R2.

  In the embodiment, the refrigerant side fins 31 are disposed in the region in the refrigerant passage 24 corresponding to the upstream portion 21a of the fluid passage 21 to be cooled and the downstream portion 24b of the refrigerant passage 24. Not exclusively. For example, as shown in FIG. 8, the refrigerant-side fins 31 may be disposed over the entire region in the refrigerant passage 24 corresponding to the upstream portion 21 a of the fluid passage 21 to be cooled. In the upstream portion 21a of the cooled fluid passage 21, since the EGR gas flows into the cooled fluid passage 21 and is at a high temperature soon, the cooled fluid side fin 30 in the partition wall 19 is brazed by the brazing material R1. The heat flux at the site tends to rise locally. However, according to this, since the refrigerant side fin 31 is disposed over the entire region in the refrigerant passage 24 corresponding to the upstream portion 21a of the fluid passage 21 to be cooled, the fluid side fin 30 in the partition wall 19 is provided. The heat flux at the part brazed by the brazing material R <b> 1 can be suppressed by the refrigerant side fins 31. In this case, as indicated by arrows X1 and X2 in FIG. 8, it is preferable that the EGR gas and water flow in parallel flow in parallel. Further, the flow direction of water may be opposite to the direction of the arrow X2 shown in FIG. 8, and the flow direction of EGR gas and water may be opposed to each other.

  In the embodiment, the refrigerant side fins 31 are disposed in the region in the refrigerant passage 24 corresponding to the upstream portion 21a of the fluid passage 21 to be cooled and the downstream portion 24b of the refrigerant passage 24. Not exclusively. For example, as shown in FIG. 9, the refrigerant-side fins 31 may be disposed over the entire downstream portion 24 b of the refrigerant passage 24. In the downstream portion 24b of the refrigerant passage 24, since the number of bubbles is large, the critical heat flux of the refrigerant tends to be small. However, according to this, since the refrigerant side fin 31 is disposed over the entire downstream portion 24b of the refrigerant passage 24, the refrigerant side fin 31 causes the fluid side fin 30 in the partition wall 19 to be cooled by the brazing material R1. The heat flux of the brazed part can be suppressed more than the critical heat flux of the refrigerant. In this case, as shown by arrows X1 and X2 in FIG. 9, it is preferable that the EGR gas and water flow in parallel flow in parallel. Further, the flow direction of water may be opposite to the direction of the arrow X2 shown in FIG. 9, and the flow direction of EGR gas and water may be opposed to each other.

  In embodiment, although the to-be-cooled fluid side fin 30 and the refrigerant | coolant side fin 31 were straight fins, it is not restricted to this. For example, as shown in FIG. 10, the cooled fluid-side fins 30 and the refrigerant-side fins 31 are formed by cutting straight fins into a plurality of small blocks 41, and each small block 41 is arranged in an offset manner. An offset fin formed by integrating the blocks 41 may be used. According to this, the EGR gas or the refrigerant flowing in the cooled fluid passage 21 or the refrigerant passage 24 can flow in both the front-rear direction and the left-right direction through the gap formed between the small blocks 41.

  In the embodiment, the unevenness intervals (pitch) of the cooled fluid-side fins 30 and the refrigerant-side fins 31 are the same, but not limited to this, for example, as shown in FIG. The unevenness interval may be narrower than the unevenness interval in the cooled fluid-side fin 30. In this case, the portion of the partition wall 19 where the cooled fluid-side fins 30 are brazed with the brazing material R1 needs to be superposed on the portion of the partition wall 19 where the refrigerant-side fins 31 are brazed with the brazing material R2.

  ○ In the heat exchanger 11 of the embodiment, the flow direction of the EGR gas and water is an orthogonal flow in which the flow directions are orthogonal, but not limited thereto, for example, as a counter flow in which the flow directions of the EGR gas and water are opposed to each other. Moreover, it is good also as a parallel flow in which the distribution | circulation direction of EGR gas and water is parallel. Even in a heat exchanger that is a counter flow or parallel flow, the same effects as in the embodiment can be obtained by disposing the refrigerant side fins 31 in the refrigerant passage 24 as in the embodiment.

  In the heat exchanger 11 of the embodiment, the flow direction of the EGR gas and water is orthogonal, but the flow direction of the EGR gas and water is not orthogonal, It may be designed to intersect.

  In the embodiment, the heat exchanger 11 is embodied in the heat exchanger 11 provided in the EGR gas boiling cooling device (EGR cooler), but is not limited thereto, for example, a cooling device for an in-vehicle device, a refrigerator, Further, the heat exchanger may be embodied in a freezer or the like.

In the embodiment, the fluid to be cooled is the EGR gas. However, the present invention is not limited to this, and the fluid to be cooled may be a gas other than the EGR gas or a high-temperature liquid.
Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.

  (A) The cooled fluid passage and the refrigerant passage are arranged side by side so that the flow direction of the cooled fluid and the flow direction of the refrigerant are orthogonal to each other. Boiling-cooled heat exchanger.

  DESCRIPTION OF SYMBOLS 11 ... Heat exchanger, 19 ... Partition, 21 ... Cooled fluid passage, 21a ... Upstream portion, 21b ... Downstream portion, 24 ... Refrigerant passage, 24a ... Upstream portion, 24b ... Downstream portion, 30 ... Cooled fluid side fin, 30c ... Standing part, 31 ... Refrigerant side fin, 31c ... Standing part, 33 ... First refrigerant side fin, 33b ... Standing part, 34 ... Second refrigerant side fin, 34b ... Standing part.

Claims (5)

Boiling cooling comprising a partition wall that partitions a cooled fluid passage through which a fluid to be cooled flows, a refrigerant passage through which a refrigerant that cools the cooled fluid flows, and a cooled fluid-side fin disposed in the cooled fluid passage. A heat exchanger,
Refrigerant-side fins are disposed in a region in the refrigerant passage determined based on the relationship between the heat flux in the partition wall and the critical heat flux of the refrigerant, and the cooled fluid-side fins and the refrigerant-side fins stand upright. Has a part,
In the region in the refrigerant passage, the partition wall side end portion of the refrigerant side fin standing portion is positioned at a position corresponding to the partition wall side end portion of the standing portion of the cooled fluid side fin. A boiling cooling type heat exchanger, wherein the refrigerant side fins are arranged.   2. The boiling cooling type according to claim 1, wherein the refrigerant side fin is disposed in a region in the refrigerant passage corresponding to an upstream portion in a flow direction of the fluid to be cooled in the fluid passage to be cooled. Heat exchanger.   The boiling cooling heat exchanger according to claim 1, wherein a refrigerant side fin is disposed in a downstream portion of the refrigerant passage in the flow direction of the refrigerant. The cooled fluid passage and the refrigerant passage are arranged in parallel so that the flow direction of the cooled fluid and the flow direction of the refrigerant intersect,
The refrigerant side fin is disposed in a region in the refrigerant passage corresponding to an upstream portion of the fluid passage to be cooled and a region in the downstream portion of the refrigerant passage. Item 4. The boiling cooling heat exchanger according to any one of items 3 to 4.   The region in the refrigerant passage defined based on the relationship between the heat flux in the partition and the critical heat flux of the refrigerant is a region in the refrigerant passage in which the heat flux in the partition is larger than the critical heat flux of the refrigerant. The boiling cooling heat exchanger according to any one of claims 1 to 4, wherein the heat exchanger is a boiling cooling type heat exchanger.

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