WO2020017176A1

WO2020017176A1 - Heat exchanger

Info

Publication number: WO2020017176A1
Application number: PCT/JP2019/022433
Authority: WO
Inventors: 岩崎　充; 真由美山中
Original assignee: カルソニックカンセイ株式会社
Priority date: 2018-07-20
Filing date: 2019-06-05
Publication date: 2020-01-23
Also published as: JP6550177B1; JP2020012621A; CN112368535B; CN112368535A

Abstract

A heat exchanger (100) comprises: tubes (50) by which first flow paths (21) through which a first fluid flows in a flow path direction and second flow paths (22) through which a second fluid flows, are separated; and inner fins (40) arranged in the first flow paths (21). Each inner fin (40) has: flat walls (41) in contact with the corresponding tube (50); upright walls (42) which extend in a direction intersecting with the flat walls (41) so as to be contiguous with the flat walls (41), and which partition the corresponding first flow path (21) into a plurality of small flow paths (23) arrayed in the flow path width direction; and fin parts (43, 44) which are cut and raised from the flat walls (41) so as to project into the small flow paths (23). Each tube (50) has an opposing dimple (77) which is recessed from a flow path surface (63) facing the corresponding first flow path (21) but protrudes from a flow path surface (62) facing the corresponding second flow path (22), and which extends over a plurality of the flat walls (41) across the small flow paths (23) so as to oppose the flow of the second fluid. The opposing dimple (77) has: a pair of tilted sections (77a) tilted relative to the flow path direction; and an intersection section (77b) at which the pair of tilted sections (77a) intersect with each other.

Description

Heat exchanger

The present invention relates to a heat exchanger in which heat exchange is performed between fluids.

JP2014-169857A discloses an exhaust heat exchanger that cools the exhaust of an internal combustion engine with cooling water.

チューブ In the exhaust heat exchanger, a tube that forms an exhaust passage is disposed inside the water tank. An inner fin as a heat transfer member for promoting heat exchange between the exhaust gas and the cooling fluid is arranged in the tube. The exhaust gas introduced into the exhaust heat exchanger flows through the tube while contacting the inner fin, and is cooled by radiating heat to cooling water flowing outside the tube.

チューブ A plurality of dimples are formed on the tube as convex portions protruding from the outer surface. The dimple is provided as means for lowering the temperature of the temperature boundary layer of the cooling water.

However, in recent years, the demand for higher performance of heat exchangers has been increasing, and even in the heat exchangers described in JP2014-169857A, room for improvement has been sought for further higher performance. .

The present invention aims to further enhance the heat exchange performance of a heat exchanger.

According to one embodiment of the present invention, the heat exchanger in which heat exchange is performed between the first fluid and the second fluid includes: a first flow path in which the first fluid flows in the flow direction; A second channel that circulates; a tube that partitions the first channel; and an inner fin that is disposed in the first channel. The inner fin is disposed in a crossing direction of the flat wall that contacts the tube and the flat wall. An upright wall dividing the first flow path into a plurality of small flow paths arranged in the width direction of the flow path, and a fin portion cut and raised from the flat wall and protruding into the small flow path; Are recessed from the flow path surface facing the first flow path and raised from the flow path surface facing the second flow path, and straddle the small flow path so as to face the flow of the second fluid. An opposing dimple extending across the wall, wherein the opposing dimple is inclined with respect to the flow path direction. It has an inclined portion of the pair that, a cross section of the inclined portion of the pair cross each other, the.

According to the above aspect, in the heat exchanger, the contact area between the tube and the inner fin is reduced by the depression of the opposing dimple. However, the heat transfer from the second fluid to the tube is promoted by the opposing dimple, and the fin portion causes the heat transfer. Heat transfer from one fluid to the tube is promoted. Thereby, a heat exchanger can raise heat exchange performance.

FIG. 1 is a perspective view showing a heat exchanger according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the heat exchanger. FIG. 3 is an exploded perspective view of the tube. FIG. 4 is a perspective view showing a cross section in which a part of the heat exchanger is cut away. FIG. 5 is a perspective view showing a cross section in which a part of the inner fin is cut away. FIG. 6 is a plan view of the inner fin. FIG. 7 is a diagram showing the relationship between the ratio A of the non-contact area due to the dimple and the temperature difference T. FIG. 8 is a perspective view showing a cross section in which a part of a heat exchanger according to a modification is cut away.

Hereinafter, the heat exchanger 100 according to the embodiment of the present invention will be described with reference to the accompanying drawings. In addition, for simplification of description, the accompanying drawings omit a part of the heat exchanger 100 for illustration.

The heat exchanger 100 is a water-cooled EGR cooler used for an EGR (Exhaust Gas Recirculation) system (not shown) of the vehicle. The heat exchanger 100 cools a part (first fluid) of the exhaust gas discharged from the engine with cooling water (second fluid). After flowing through the heat exchanger 100, the cooling water circulating through the cooling circuit flows through the radiator and radiates heat to the outside air.

As shown in FIGS. 1 and 2, in the heat exchanger 100, cooling water circulates between a plurality of tubes 50 forming a first flow path 21 through which exhaust gas flows, and the tubes 50 stacked. And a casing 10 that forms the second flow path 22.

Hereinafter, the configuration of the heat exchanger 100 will be described by setting three axes of X, Y, and Z orthogonal to each other in each drawing. In the tube 50, the X-axis direction in which the first flow path 21 extends is referred to as “flow path direction”, and the Y-axis direction is referred to as “flow path width direction”.

As shown in FIG. 2, the tube 50 is formed in a flat cylindrical shape in the Z-axis direction by assembling the half-cylinder upper plate 60 and the lower plate 80. The inner fin 40 is disposed between the upper plate 60 and the lower plate 80 as a heat transfer member.

The upper plate 60 and the lower plate 80 are formed into a flat semi-cylindrical shape by pressing a metal plate.

The upper plate 60 has a plate-shaped heat transfer plate 61 extending in the X-axis direction and the Y-axis direction. One diagonal dimple 71, one upstream diagonal dimple 72, and four vertical dimples 73 (dimples) that guide the flow of the cooling water are provided on the heat transfer plate 61 as described later. Linear dimples) and many opposing dimples 77 (vortex generating dimples) are formed.

The lower plate 80 has a plate-shaped heat transfer plate portion 81 extending in the X-axis direction and the Y-axis direction. One diagonal dimple 91, one upstream diagonal dimple 92, and four vertical dimples 93 (linear dimples) are formed in the heat transfer plate portion 81 as dimples.

The diagonal dimples 71 and 91, the upstream diagonal dimples 72 and 92, and the

vertical dimples

73 and 93 are opposed to each other in the Z-axis direction and protrude into the second flow path 22 to guide the flow of the cooling water. .

The casing 10 is formed in a substantially rectangular cylindrical shape by assembling the half-cylindrical upper shell 20 and the lower shell 30.

Pipes

17 and 18 are connected to the casing 10.

As shown in FIG. 1, inside the casing 10, a second inlet 25 for distributing cooling water guided from the pipe 17 to the second flow path 22 between the tubes 50, and a cooling water flowing out of the second flow path 22. A second outlet 27 for guiding water to the pipe 18 is provided.

ＥＧEGR passage pipes (not shown) are connected to both open ends of the casing 10 via frame-

shaped headers

15 and 16. Inside the header 15, a first inlet 35 for distributing exhaust gas guided from a tube of the EGR passage to the first flow path 21 is provided. Inside the header 16, a first outlet 36 that guides exhaust gas flowing out of the first flow path 21 to a pipe of the EGR passage is provided.

製造 When the heat exchanger 100 is manufactured, an assembly in which the above members are assembled is formed. The metal assembly is conveyed to a heating furnace and subjected to heat treatment, so that each joint is joined by brazing.

When the heat exchanger 100 operates, the cooling water circulating in the cooling circuit flows into the second inlet 25 from inside the pipe 17 and flows into the second flow path 22 between the tubes 50 as shown by the black arrow in FIG. Be distributed. The cooling water flowing through the second flow path 22 gathers at the second outlet 27 and flows out through the pipe 18. On the other hand, the exhaust gas flowing through the EGR passage is distributed to the first flow passage 21 in each tube 50 through the first inlet 35 in the header 15 as shown by a white arrow in FIG. The exhaust gas flowing through the first flow path 21 is cooled by radiating heat to the cooling water flowing through the second flow path 22 through each tube 50. Exhaust gas flowing out of the first flow path 21 is collected through a first outlet 36 in the header 16 and supplied to a combustion chamber of the engine.

Next, the configuration of the tube 50 will be described with reference to FIGS.

FIG. 3 is a perspective view showing the upper plate 60 and the inner fin 40 in a state where the tube 50 is disassembled. The inner fin 40 has a corrugated shape having a substantially rectangular cross section. In the tube 50, flat walls 41 extending in the X-axis direction and the Y-axis direction, and upright walls 42 connected in the crossing direction (the X-axis direction and the Z-axis direction) of the flat walls 41 are alternately arranged. The offset type inner fin 40 is offset so that the positions of the flat wall 41 and the upright wall 42 are displaced by a predetermined length in the Y-axis direction for each section divided by a predetermined length in the X-axis direction.

FIG. 4 is a perspective view showing a cross section of the tube 50 with a part cut away. The first flow path 21 is formed as a flat space between the upper plate 60 and the lower plate 80. The first flow path 21 is divided into a plurality of small flow paths 23 by each segment including the flat wall 41 and the upright wall 42 of the inner fin 40.

FIG. 5 is a perspective view showing a part of the inner fin 40 in an enlarged manner. The inner fin 40 has an upstream fin portion 43 and a downstream fin portion 44 cut and raised from the flat wall 41 for each segment.

Fins

45 and 46 are formed in the flat wall 41 at the positions where the

fins

43 and 44 are cut and raised. The inner fin 40 is formed by press working.

フィン The fin 43 on the upstream side is cut and raised so as to face upstream in the exhaust gas flow direction. The fin portion 43 has a trapezoidal shape having a bent side 43a bent from the flat wall 41, an inclined side 43b crossing the small flow path 23, and a long side 43c and a short side 43d connecting the bent side 43a and the inclined side 43b. It is formed.

The fin portion 44 on the downstream side is cut and raised so as to face the downstream side in the exhaust gas flow direction. The fin portion 44 has a trapezoidal shape having a bent side 44a bent from the flat wall 41, an inclined side 44b crossing the small channel 23, and a long side 44c and a short side 44d connecting the bent side 44a and the inclined side 44b. It is formed.

The bent side 43a of the fin 43 on the upstream side and the bent side 44a of the fin 44 on the downstream side are inclined at substantially the same angle with respect to the Y axis, and are disposed substantially parallel to each other.

The inclined side 43b of the upstream fin portion 43 and the inclined side 44b of the downstream fin portion 44 are arranged so as to incline with respect to the Y axis and cross the small flow path 23. As described later, the flow of the exhaust gas flowing through the first flow path 21 turns around the X axis by being blocked by the

inclined sides

43b, 44b of the

fin portions

43, 44 extending in an oblique direction with respect to the Y axis. It becomes a spiral vertical vortex.

As shown in FIG. 3, a plurality of opposed dimples 77 are formed on the heat transfer plate portion 61 of the upper plate 60 so as to be arranged along the vertical dimples 73. The distance L between the opposing dimples 77 arranged in the X-axis direction is arbitrarily set according to the performance required of the heat exchanger 100 as described later.

The V-shaped opposed dimple 77 has a pair of inclined portions 77a inclined with respect to the Y axis, and an intersection 77b where the pair of inclined portions 77a intersect with each other. The opposed dimple 77 is inclined such that the pair of inclined portions 77a are opened toward the upstream side in the exhaust flow direction, and the intersection portion 77b is projected toward the downstream side in the exhaust flow direction. As described later, the flow of the cooling water flowing through the second flow path 22 is interrupted by the inclined portion 77a of the opposed dimple 77 extending in an oblique crossing direction with respect to the Y axis, so that the spiral water turns around the X axis. Vertical vortex.

対向 As shown in FIG. 4, the opposing dimple 77 is formed on the upper plate 60 by pressing. The opposed dimple 77 protrudes in a bank shape with respect to the channel surface 62 of the upper plate 60 facing the second channel 22, and forms a groove with respect to the channel surface 63 of the upper plate 60 facing the first channel 21. Dent. The opposing dimple 77 has a groove-like depression 77c. The vertical dimple 73 is similarly formed on the upper plate 60 by pressing. The vertical dimple 73 has a groove-like depression 73c. The lower plate 80 is formed with a vertical dimple 93 by press working. The vertical dimple 93 has a groove-like depression 93c.

FIG. 6 is a plan view showing the inner fin 40 by a solid line and the upper plate 60 by a two-dot chain line. In the upper plate 60, a portion facing the flat wall 41 of the inner fin 40 via the small flow path 23 and a portion contacting and joining the flat wall 41 are alternately arranged in the Y-axis direction.

The V-shaped opposed dimple 77 extends over the small wall 23 in the Y-axis direction and over the flat wall 41 of a plurality of (four) segments.

The linear vertical dimple 73 extends over the small wall 23 in the X-axis direction over the flat walls 41 of the plurality of segments.

As shown in FIG. 4, the

fin openings

45, 46 that open after the

fins

43, 44 of the inner fin 40 are cut and raised have a portion facing the depression 93 c of the vertical dimple 93. Further, the

fin openings

45 and 46 of the inner fin 40 have portions facing the depression 77 c of the opposed dimple 77 and the depression 73 c of the vertical dimple 73.

Next, the operation of the heat exchanger 100 will be described.

When the heat exchanger 100 is operated, the exhaust gas flowing through the EGR passage flows through the first flow path 21 while contacting the inner fin 40 and the tube 50, and the cooling water flows through the second flow path 22 through the tube 50. It is cooled by radiating heat. The inner fin 40 functions as a heat transfer member that transfers the heat of the exhaust to the upper plate 60 and the lower plate 80 of the tube 50.

(4) The flow of exhaust gas flowing through the first flow path 21 is blocked obliquely with respect to the X axis by the

fin portions

43 and 44 of the inner fin 40, thereby generating a spiral vertical vortex swirling around the X axis. Thus, in the first flow path 21, in the region including the inner wall surface (flow path surface 63) of the tube 50 and the boundary layer near the surface of the inner fin 40, heat transfer of the exhaust gas is promoted by the vortex (turbulence). The vertical vortex of the exhaust gas generated on the downstream side of the

fins

43 and 44 has a reduced exhaust flow resistance and a larger turbulent flow area in the X-axis direction than the horizontal vortex circling around the Y-axis. .

On the other hand, the flow of the cooling water flowing through the second flow path 22 is blocked by the opposed dimple 77 in a direction obliquely crossing the X axis, thereby generating a spiral vertical vortex swirling around the X axis. Accordingly, in the region including the boundary layer near the outer wall surface (flow path surface 62) of the tube 50 in the second flow path 22, heat transfer of exhaust gas is promoted by eddy current (turbulent flow).

The vertical vortex of the cooling water generated on the downstream side of the opposed dimple 77 has a lower flow resistance than the horizontal vortex swirling around the Y axis. Limited to Therefore, in the heat exchanger 100, the heat transfer of the cooling water is promoted and the heat exchange efficiency is increased by reducing the interval L between the opposed dimples 77 arranged in the X-axis direction to a certain extent.

However, in the heat exchanger 100, when the interval L between the opposing dimples 77 is reduced, the area where the recess 77c of the opposing dimple 77 faces the inner fin 40 increases, so that the non-contact area between the tube 50 and the inner fin 40 increases. I do. For this reason, in the heat exchanger 100, when the interval L between the opposed dimples 77 is made smaller than a certain level, the heat transfer amount of the inner fins 40 decreases, and the heat exchange efficiency decreases.

FIG. 7 shows that the temperature difference T of the cooling water caused by flowing the heat exchanger 100 during the operation in which the cooling water and the exhaust gas flow through the heat exchanger 100 under a predetermined condition indicates the ratio A of the non-contact area due to the dimple. 2 shows the result obtained by a simulation analysis of a value that changes according to. The temperature difference T of the cooling water is the difference between the temperature of the cooling water flowing through the second inlet 25 and the temperature of the cooling water flowing through the second outlet 27. The ratio A of the non-contact area due to the dimple is as follows when the dimple is provided with respect to the contact area B between the tube 50 and the inner fin 40 when the dimple (the opposed dimple 77, the vertical dimple 73, and the vertical dimple 93) is not provided. This is the ratio of the contact area C between the tube 50 and the inner fin 40 and is expressed by the following equation.
A = (C / B) × 100

As shown in FIG. 7, the temperature difference T of the cooling water gradually increases as the ratio A of the non-contact area due to the dimple becomes larger than 0%, takes a peak value, and gradually increases as the ratio A increases after the peak value is obtained. Lower. Then, when the ratio A is in the range of 2% to 14%, the temperature difference T is equal to or more than the reference value required in the market.

In the heat exchanger 100, based on the result of the simulation analysis, the distance L between the opposed dimples 77 arranged in the X-axis direction is set such that the ratio A of the non-contact area due to the dimples falls within the range of 2% or more and 14% or less. Is set.

Next, effects of the present embodiment will be described.

According to the present embodiment, the heat exchanger 100 includes the first flow passage 21 through which the exhaust gas (the first fluid) flows in the X-axis direction (the flow direction) and the second flow passage 21 through which the cooling water (the second fluid) flows. A tube 50 for partitioning the flow path 22, and an inner fin 40 disposed in the first flow path 21, wherein the inner fin 40 extends in a direction in which the flat wall 41 contacts the tube 50 and the flat wall 41. An upstanding wall 42 which is continuous and partitions the first flow path 21 into a plurality of small flow paths 23 arranged in the Y-axis direction (flow path width direction), and a fin portion 43 cut and raised from the flat wall 41 and protruding into the small flow path 23. , 44, and the tube 50 is depressed from the flow path surface 63 facing the first flow path 21 and protrudes from the flow path surface 62 facing the second flow path 22, and faces the flow of the second fluid. Dimple 77 extending across a plurality of flat walls 41 across the small flow path 23 as shown in FIG. Has, opposing dimples 77 was configured to have an inclined portion 77a of the pair of inclined with respect to the X-axis direction (channel direction), the cross section 77b of the inclined portions 77a of the pair cross each other, the.

Based on the above configuration, in the heat exchanger 100, the inner fins 40 and the tubes 50 transfer heat between the exhaust gas and the cooling water. However, by providing the recesses 77c of the opposed dimples 77, the tubes 50 and the inner fins 40 are provided. The contact area with is reduced. On the other hand, since the cooling water is guided by the opposing dimples 77, heat transfer from the cooling water to the tube 50 is promoted. The

fin portions

43 and 44 generate a vortex in the flow of the exhaust gas, so that heat transfer from the exhaust gas to the tube 50 is promoted. Thus, the heat exchanger 100 has improved heat exchange performance, and can be reduced in size and weight.

Furthermore, the cooling water flowing in the second flow path 22 in the X-axis direction is swirled by passing through the opposing dimples 77 arranged so as to cross the second flow path 22. Thus, in the heat exchanger 100, the vortex is generated in the flow of the cooling water, so that heat transfer from the cooling water to the tube 50 is promoted.

Furthermore, the cooling water flowing through the second flow path 22 passes through the inclined portion 77a inclined with respect to the X-axis direction and the intersection portion 77b, and becomes a vertical vortex. In this way, in the heat exchanger 100, a longitudinal vortex is generated in the flow of the cooling water by the opposed dimples 77, thereby promoting the heat transfer from the cooling water to the tube 50 while reducing the flow resistance of the cooling water.

The heat exchanger 100 includes a first flow path 21 through which exhaust gas (first fluid) flows in the X-axis direction (flow direction), a second flow path 22 through which cooling water (second fluid) flows, And the inner fin 40 disposed in the first flow path 21. The inner fin 40 is connected to the flat wall 41 in contact with the tube 50 in the cross direction of the flat wall 41, and An upright wall 42 that partitions the path 21 into a plurality of small flow paths 23 arranged in the Y-axis direction (flow path width direction), and

fin portions

43 and 44 cut and raised from the flat wall 41 and protruding into the small flow paths 23. The tube 50 is depressed from the flow path surface 63 facing the first flow path 21 and protrudes from the flow path surface 62 facing the second flow path 22 so as to face the flow of the second fluid. An opposing dimple 77 extending over the plurality of flat walls 41 over the first flow path 2;

Vertical dimples

73 and 93 protruding from the flow path surface 62 facing the second flow path 22 and extending in the X-axis direction (flow direction). The opposing dimple 77 may be configured to be arranged along the vertical dimples 83 and 93.

Based on the above configuration, in the heat exchanger 100, the inner fins 40 and the tubes 50 transfer heat between the exhaust gas and the cooling water. However, by providing the recesses 77c of the opposed dimples 77, the tubes 50 and the inner fins 40 are provided. Area in contact with On the other hand, since the cooling water is guided by the opposing dimples 77, heat transfer from the cooling water to the tube 50 is promoted. The

fin portions

Further, since the cooling water flowing through the second flow path 22 flows along the pair of

vertical dimples

73 and 93 facing each other, the force flowing in the X-axis direction increases, and the cooling water flowing along the

vertical dimples

73 and 93 is increased. Each time the dimples 77 exceed the opposing dimples 77, a strong vortex flows. Thereby, heat transfer from the cooling water to the tube 50 is promoted. Further, since the opposed dimples 77 are formed on only one of the pair of tubes 50 stacked on each other, the flow resistance of the cooling water is suppressed.

fin portions

43 and 44 cut and raised from the flat wall 41 and projecting into the small flow paths 23. The tube 50 has opposed dimples 77 and vertical dimples 73 and 93 (dimples) that are depressed from the flow path surface 63 facing the first flow path 21 and protrude from the flow path surface 62 facing the second flow path 22. Then, the opposed dimple 77 and the vertical dimple 7 are , The ratio A of the non-contact area which the tube 50 does not contact with the inner fin 40 by 93 (dimples) is provided, may be configured to be set in the range of 14% or more 2%.

Based on the above configuration, in the heat exchanger 100, the inner fins 40 and the tubes 50 transfer heat between the exhaust gas and the cooling water, but the opposed dimples 77 and the

depressions

77c, 73c, 93c of the

vertical dimples

73, 93 are provided. As a result, the contact area between the tube 50 and the inner fin 40 is reduced. On the other hand, the cooling water is guided by the opposed dimples 77 and the

vertical dimples

73 and 93, so that heat transfer from the cooling water to the tube 50 is promoted. The

fin portions

Further, the non-contact area between the tube 50 and the inner fin 40 due to the

recesses

77c, 73c, 93c of the opposing dimple 77 and the

vertical dimples

73, 93 is suppressed, and the cooling water guided to the opposing dimple 77, the

vertical dimples

73, 93. The effect of promoting heat transfer from the cooling water to the tube 50 by the flow (vortex) is sufficiently obtained. Thereby, the heat exchanger 100 can obtain heat exchange performance required in the market.

Further, according to the present embodiment, in the heat exchanger 100, the first flow path 21 through which the exhaust gas (the first fluid) flows in the X-axis direction (the flow path direction) and the cooling water (the second fluid) flow. A tube 50 for partitioning the second flow path 22 and the inner fin 40 arranged in the first flow path 21 are provided. The inner fin 40 is continuous with the flat wall 41 in contact with the tube 50 and in the crossing direction of the flat wall 41, and partitions the first flow path 21 into a plurality of small flow paths 23 arranged in the Y-axis direction (flow path width direction). It has a wall 42 and

fin portions

43 and 44 cut and raised from the flat wall 41 and protruding into the small channel 23. The tube 50 is configured to have the opposed dimples 77 and the vertical dimples 73 and 93 (dimples) that are depressed from the flow path surface 63 facing the first flow path 21 and protrude from the flow path surface 62 facing the second flow path 22. .

depressions

77c, 73c, 93c of the

vertical dimples

fin portions

チューブ In addition, the tube 50 is configured to include, as dimples, opposing dimples 77 extending across the plurality of flat walls 41 across the small flow path 23 so as to oppose the flow of the cooling water (second fluid).

基づき Based on the above configuration, the cooling water flowing in the second flow path 22 in the X-axis direction passes through the opposing dimples 77 arranged so as to cross the second flow path 22 to be swirled. Thus, in the heat exchanger 100, the vortex is generated in the flow of the cooling water, so that heat transfer from the cooling water to the tube 50 is promoted.

Further, in the opposed dimple 77, a pair of inclined portions 77a inclined with respect to the X-axis direction (flow path direction) so as to face the flow of the cooling water (second fluid), and the pair of inclined portions 77a cross each other. And an intersecting portion 77b.

に Based on the above configuration, the cooling water flowing through the second flow path 22 passes through the inclined portion 77a and the intersection portion 77b that are inclined with respect to the X-axis direction, and becomes a vertical vortex. In this way, in the heat exchanger 100, a longitudinal vortex is generated in the flow of the cooling water by the opposed dimples 77, thereby promoting the heat transfer from the cooling water to the tube 50 while reducing the flow resistance of the cooling water.

The tube 50 has, as dimples,

vertical dimples

73 and 93 extending in the X-axis direction (flow path direction). The plurality of opposing dimples 77 were arranged along the opposing dimples 77.

に Based on the above configuration, the cooling water flowing through the second flow path 22 flows along the

vertical dimples

73 and 93 in the X-axis direction. By arranging the plurality of opposing dimples 77 along the opposing dimples 77, the cooling water circulates as a vortex each time it passes over the opposing dimples 77. Thus, in the heat exchanger 100, the vortex of the cooling water is generated in the X-axis direction, so that the heat transfer from the cooling water to the tube 50 is promoted.

The

vertical dimples

73 and 93 are configured to face each other in the Z-axis direction (stacking direction) and protrude into the second flow path 22.

Based on the above configuration, the cooling water flowing through the second flow path 22 flows along the pair of

vertical dimples

73 and 93 facing each other, so that the force flowing in the X-axis direction increases, and the cooling water flows along the

vertical dimples

73 and 93. Each time it passes over a plurality of opposing dimples 77, it becomes a strong vortex. Thereby, heat transfer from the cooling water to the tube 50 is promoted. Further, since the opposed dimples 77 are formed on only one of the pair of tubes 50 stacked on each other, the flow resistance of the cooling water is suppressed.

The

fin openings

45 and 46, which open where the

fins

43 and 44 of the inner fin 40 are cut and raised, face the opposing dimples 77 of the tube 50 and the

depressions

77c, 73c and 93c of the vertical dimples 73 and 93 (dimples). It has the structure which has the part which does.

Since the opposed dimples 77 and the vertical dimples 73 and 93 (dimples) are provided on the tube 50, the non-contact area ratio A where the tube 50 does not contact the inner fin 40 is set to a range of 2% or more and 14% or less. Configuration.

Based on the above configuration, in the heat exchanger 100, the non-contact area between the tube 50 and the inner fin 40 due to the opposing dimple 77, the

depression

77 c, 73 c, 93 c of the

vertical dimple

73, 93 is suppressed, and the opposing dimple 77, the vertical dimple The effect of promoting the heat transfer from the cooling water to the tube 50 by the flow of the cooling water (vortex) guided to 73 and 93 is sufficiently obtained. Thereby, the heat exchanger 100 can obtain heat exchange performance required in the market.

Next, a modified example of the tube 50 shown in FIG. 8 will be described.

The tube 50 of the above embodiment has a configuration in which the opposing dimples 77 are formed on the upper plate 60 and no opposing dimples are formed on the lower plate 80. On the other hand, the tube 50 according to the present modified example has a configuration in which the opposing dimples 77 are formed on the upper plate 60 and the opposing dimples 97 are also formed on the lower plate 80.

The opposing dimples 77 of the upper plate 60 and the opposing dimples 97 of the lower plate 80 have the same V-shape, and are arranged at the same position in the Z-axis direction. The intersection 77b of the opposing dimple 77 and the intersection (not shown) of the opposing dimple 97 are arranged at the same position in the Z-axis direction.

熱 The heat exchanger 100 according to the present modification has a configuration in which a pair of opposing

dimples

77 and 97 oppose each other in the Z-axis direction (stacking direction) and protrude into the second flow path 22.

に Based on the above configuration, the cooling water flowing through the second flow path 22 flows over both of the opposing

dimples

77 and 97 facing each other, so that the power of the vortex is increased. Thereby, heat transfer from the cooling water to the tube 50 is promoted.

As described above, the embodiment of the present invention has been described. However, the above embodiment is only a part of an application example of the present invention, and the technical scope of the present invention is not limited to the specific configuration of the above embodiment. Absent.

For example, the opposed dimple 77 (vortex generating dimple) in the above-described embodiment protrudes in a V-shape, but is not limited thereto, and may be, for example, a W-shape. The W-shaped opposed dimple 77 has two pairs of inclined portions and two intersections. In this case, the region where the vertical vortex of the cooling water is generated by the opposed dimples 77 expands in the Y-axis direction, and the effect of promoting heat transfer from the cooling water to the tube 50 is enhanced.

The

fin portions

43 and 44 of the above embodiment are cut and raised in a trapezoidal shape having four sides, but are not limited thereto, and may be cut and raised in a polygonal shape having five or more sides.

The present invention is suitable as a heat exchanger mounted on a vehicle, but can also be applied to a heat exchanger used other than a vehicle.

This application claims the priority based on Japanese Patent Application No. 2018-136947 filed with the Japan Patent Office on July 20, 2018, the entire contents of which are incorporated herein by reference.

Claims

A heat exchanger in which heat exchange is performed between a first fluid and a second fluid,
A tube that partitions a first flow path in which the first fluid flows in the flow direction and a second flow path in which the second fluid flows,
An inner fin disposed in the first flow path;
The inner fin is
A flat wall contacting the tube;
An upright wall extending in the crossing direction of the flat wall and partitioning the first flow passage into a plurality of small flow passages arranged in the flow passage width direction;
A fin portion cut out from the flat wall and protruding into the small flow path,
The tube is depressed from a flow path surface facing the first flow path, and protrudes from a flow path surface facing the second flow path, and straddles the small flow path so as to face a flow of a second fluid. Having opposing dimples extending over the flat wall of
The opposing dimple,
A pair of inclined portions inclined with respect to the flow path direction,
An intersection where the pair of inclined portions intersect each other,
Heat exchanger.
The heat exchanger according to claim 1, wherein
A pair of the opposing dimples projecting into the second flow path facing each other;
Heat exchanger.
A heat exchanger in which heat exchange is performed between a first fluid and a second fluid,
A tube that partitions a first flow path in which the first fluid flows in the flow direction and a second flow path in which the second fluid flows,
An inner fin disposed in the first flow path;
The inner fin is
A flat wall contacting the tube;
An upright wall extending in the crossing direction of the flat wall and partitioning the first flow passage into a plurality of small flow passages arranged in the flow passage width direction;
A fin portion cut out from the flat wall and protruding into the small flow path,
The tube is
The plurality of flat walls are depressed from the flow path surface facing the first flow path, and protrude from the flow path surface facing the second flow path, and straddle the small flow path so as to face the flow of the second fluid. Opposed dimples extending over
A vertical dimple that is depressed from the flow path surface facing the first flow path, and protrudes from the flow path surface facing the second flow path, and extends in the flow direction.
The plurality of opposing dimples are arranged along the vertical dimples,
Heat exchanger.
The heat exchanger according to claim 3, wherein
The vertical dimples of the pair are opposed to each other and protrude into the second flow path.
Heat exchanger.
A heat exchanger in which heat exchange is performed between a first fluid and a second fluid,
A tube that partitions a first flow path in which the first fluid flows in the flow direction and a second flow path in which the second fluid flows,
An inner fin disposed in the first flow path;
The inner fin is
A flat wall contacting the tube;
An upright wall extending in the crossing direction of the flat wall and partitioning the first flow passage into a plurality of small flow passages arranged in the flow passage width direction;
Having a fin portion cut and raised from the flat wall and protruding into the small flow path,
The tube has a dimple that is depressed from a flow path surface facing the first flow path and protrudes from a flow path surface facing the second flow path,
The ratio of the non-contact area where the tube is not in contact with the inner fin by being provided with the dimple is set in a range of 2% to 14%.
Heat exchanger.