WO2022054963A1

WO2022054963A1 - Heat exchanger

Info

Publication number: WO2022054963A1
Application number: PCT/JP2021/034017
Authority: WO
Inventors: 卓也文後; 慶彦岡▲崎▼
Original assignee: 株式会社ティラド
Priority date: 2020-09-14
Filing date: 2021-09-09
Publication date: 2022-03-17
Also published as: JPWO2022054963A1; CN115997097A; DE112021004801T5

Abstract

A heat exchanger that dissipates heat from an object to be heat exchanged to a heat exchange medium, with improved heat dissipation efficiency on the downstream side of the heat exchange medium.　In the present invention, the upward-sloping surface 6b and the downward-sloping surface 6c of each wave 6 of a corrugated fin 5 interposed in a heat exchanger body are formed with alternating recessed and protruding ridges 10 in the thickness direction of the strip-shaped metal plate thereof. The inclination angle of each of the recessed and protruding ridges 10 is within the range of 10-60 degrees with respect to the main flow of a heat exchange medium 21, and the adjacent recessed and protruding ridges 10 are arranged in the same direction. This structure allows the heat exchange medium 21 flowing inside the corrugated fin 5 to circulate, thereby improving the heat dissipation performance on the downstream side of the heat exchange medium 21.

Description

Heat exchanger

Regarding heat exchangers that dissipate heat of heat exchange objects to heat exchange media, especially heat exchangers that dissipate heat of heat exchange objects such as semiconductor elements.

As a conventional technique, in a heat sink that dissipates heat from a heat exchange object such as a semiconductor element, heat is conducted from the heat exchange object to the core, and heat is transferred from the core to the heat exchange medium to raise the temperature of the heat exchange object. Some are known to decline.
In such a heat sink, the heat exchange medium circulating inside the heat sink sequentially exchanges heat with the core according to the flow.

However, when the heat exchange medium that has been heat-exchanged with the heat exchange object in the upstream region of the flow reaches the downstream region of the flow, the temperature rises due to heat exchange, so that the heat exchange is located in the downstream region. The heat exchange performance of the object deteriorates. As a result, heat dissipation of the heat exchange object located in the downstream region of the flow of the heat exchange medium is hindered, and the temperature of the heat exchange object at that position increases.
Therefore, in order to solve this problem, a heat exchanger that suppresses the deterioration of the heat exchange performance of the heat exchange target located on the downstream side of the heat exchange medium and suppresses the temperature increase of the heat exchange target located in the downstream region. Provides the structure of.

The present invention according to claim 1 has a pair of top plate plates 2 and bottom plate plates 3 facing apart from each other, and has a box shape including a peripheral wall portion 4 covering the outer periphery of the pair of

plates

2 and 3. The heat exchanger main body 1 of the above is formed, and an inner fin is interposed inside the heat exchanger main body 1.
The inner fin is a corrugated fin 5 in which a strip-shaped metal plate is folded back into a corrugated shape.
The ridge line portion 6a of each wave 6 of the corrugated fin 5 is joined to the pair of

plates

2 and 3, and heat is exchanged with the opposite surface of the fin joint surface of at least one of the pair of

plates

2 and 3. The object 20 is attached,
In a heat exchanger in which a heat exchange medium 21 flows inside the heat exchanger main body 1 along the wave ridge direction of the corrugated fins 5 and exchanges heat with the heat exchange object 20.
Concavo-convex stripes 10 are alternately formed on the rising surface 6b and the rising surface 6c of each wave 6 in the thickness direction of the strip-shaped metal plate.
Each of the uneven strips 10 has an inclination angle of 10 to 60 degrees with respect to the mainstream of the heat exchange medium 21, and the adjacent uneven strips 10 are arranged in the same direction as a heat exchanger.
The present invention according to claim 2 is the heat exchanger according to claim 1.
When the heat exchange object 20 is attached to only one of the pair of

plates

2 and 3 joined to the ridge line portion 6a of the corrugated fin 5.
The heat exchanger is formed so that the uneven strips 10 move away from the heat exchange object 20 as the uneven strips 10 move from the upstream to the downstream of the mainstream of the heat exchange medium 21.
The present invention according to claim 3 is the heat exchanger according to any one of

claims

1 and 2.
Let A be the distance between the

adjacent surfaces

6b and 6c of each wave 6 of the corrugated fin 5.
When the height of the unevenness of the uneven strip 10 is Wh,
It is a heat exchanger characterized by having a Wh / A value of 0.1 or more and 0.8 or less.
The present invention according to claim 4 is the heat exchanger according to claim 3.
The heat exchanger is characterized in that the value of Wh / A is 0.15 or more and 0.68 or less.

According to the first aspect of the present invention, uneven strips 10 are alternately formed on the rising surface 6b and the rising surface 6c of each wave 6 of the corrugated fin 5 in which the strip-shaped metal plate is bent back in a wavy shape in the thickness direction of the strip-shaped metal plate. Each of the uneven stripes 10 is formed and has an inclination angle of 10 to 60 degrees with respect to the mainstream of the heat exchange medium 21, and the adjacent uneven strips 10 are arranged in the same direction as a heat exchanger.
According to this structure, the heat exchange medium 21 in the groove portion of the uneven strip 10 arranged at an angle on the facing upper surface 6b and the rising surface 6c (flow path) of the heat exchange medium 21 is shown in FIG. 4 (A). As shown in FIG. 4, after heat exchange with the heat exchange object while moving along the grooves formed on the

surfaces

6b and 6c, the ridge portion 6a where the inclined groove disappears away from the groove (FIG. 4). (B) to FIG. 4 (D)).
On the other hand, the heat exchange medium 21 that has not exchanged heat with the heat exchange target 20 outside the groove in the flow path flows into the groove and exchanges heat with the heat exchange object 20 to exchange heat. Deterioration of heat exchange performance in the downstream portion of the medium 21 is suppressed, and improvement in heat dissipation of the heat exchange target arranged in the downstream region can be expected.
In the invention according to claim 2, in the heat exchanger according to claim 1, the heat exchange object 20 is attached to only one of the pair of

plates

2 and 3 joined to the ridge portion 6a of the corrugated fin 5. When attached, each uneven strip 10 is formed so as to move away from the heat exchange object 20 from the upstream to the downstream of the mainstream of the heat exchange medium 21.
According to this structure, the heat exchange medium that has not undergone heat exchange flows through the groove in the vicinity of the heat exchange target, and further improvement in heat exchange performance can be expected.
According to the third aspect of the present invention, in the heat exchanger according to the first or second aspect, the distance between the

adjacent surfaces

6b and 6c of each wave 6 of the corrugated fin 5 is set to A, and the unevenness thereof. When the height of the unevenness of the strip 10 is Wh, the value of Wh / A is 0.1 or more and 0.8 or less.
With this configuration, it can be used in a range where the heat exchange performance is high even when the pressure loss is taken into consideration.
The invention according to claim 4 is the heat exchanger according to claim 3, wherein the Wh / A value is 0.15 or more and 0.68 or less.
With this configuration, the heat exchange performance can be used in a range higher than that of the invention of claim 3.

FIG. 1 is an exploded perspective view showing the heat exchanger of the present invention.
FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1 of the same heat exchanger.
FIG. 3 is a perspective view (A) of a main part showing the structure of the corrugated fin 5 of the first embodiment used for the core of the heat exchanger, a side view (B) of the corrugated fin 5, and a front view of the corrugated fin 5. C).
FIG. 4 is an explanatory diagram of heat transfer of the heat exchange medium 21 circulating in the corrugated fin (concave and convex strip 10 downward slope) 5.
FIG. 5 is an explanatory diagram of heat transfer of the heat exchange medium 21 circulating in the corrugated fin 5 in which the pattern is not formed.
FIG. 6 is a heat dissipation characteristic diagram showing a comparison between the first embodiment by thermo-fluid analysis and the corrugated fin 5 having no pattern formed.
FIG. 7 is an explanatory diagram of heat transfer of the heat exchange medium 21 circulating in the corrugated fin 5 (concave and convex strip 10 rising to the right) of the second embodiment used for the core of the heat exchanger of the present invention.
FIG. 8 is a heat dissipation characteristic diagram showing a comparison with the corrugated fins 5 of the first embodiment and the second embodiment by thermal fluid analysis.
FIG. 9 is a diagram showing a comparison of the dependence of the degree of circulation N between the corrugated fins 5 used for the core of the heat exchanger of the present invention and the corrugated fins 5 having no pattern formed.
FIG. 10 is a cross-sectional view showing another embodiment of the heat exchanger of the present invention.

Next, an embodiment of the present invention will be described with reference to the drawings.
The heat exchanger of the present invention has an optimum structure for use as a heat sink or the like that dissipates heat from a heat exchange object such as a semiconductor element.
This heat exchanger has a pair of top plate plates 2 and bottom plate plates 3 facing apart from each other, and is a box-shaped heat exchanger composed of a peripheral wall portion 4 covering the outer periphery of the pair of

plates

2 and 3. The main body 1 is formed.
In the heat exchanger body 1 of this example, as shown in FIG. 1, the top plate plate 2 covers the opening of the cup plate formed by the bottom plate plate 3 and the peripheral wall portion 4 integrally rising from the outer peripheral edge thereof. It fits. The heat exchanger main body 1 shown in FIG. 1 is an example, and is not limited to this shape. The peripheral wall portion 4 may be separate from the bottom plate plate 3.
Inside the heat exchanger main body 1, an inner fin forming the core is interposed. The inner fin is composed of a corrugated fin 5 in which a strip-shaped metal plate is folded back into a corrugated shape.
The corrugated fin 5 has a rising surface 6b and a rising surface 6c facing each other on one wave 6, and has a ridge portion 6a connecting them in a wavy shape.
As shown in FIG. 2, the ridge line portion 6a of each wave 6 is joined to the pair of top plate plates 2 and bottom plate plates 3.
A heat exchange object 20 is attached to the outer surface (opposite surface of the fin joint surface) of at least one of the pair of

plates

2 and 3 in the heat exchanger main body 1. In this example, the heat exchange object 20 is attached to the outer surface of the top plate 2.
On the outer surface of the heat exchanger main body 1, an inlet 22 into which the heat exchange medium 21 flows in and an outlet 23 through which the heat exchange medium 21 flows out are provided. The heat exchange medium 21 circulates along the ridgeline direction of the wave ridgeline portion 6a of the corrugated fins 5 arranged inside the heat exchanger main body 1.
As an example, a refrigerant such as cooling water can be used as the heat exchange medium 21.
As an example, as shown in FIG. 1, when a plurality of heat exchange objects 20 are arranged on the outer surface of the top plate 2 at intervals along the flow of the heat exchange medium 21, the heat exchange objects 20 are generated. The heat is conducted to the corrugated fin 5 via the top plate 2, and the heat is transferred from the corrugated fin 5 to the heat exchange medium 21, so that the temperature of the heat exchange object 20 is lowered. In such a heat exchanger, the heat exchange medium 20 circulating inside the heat exchanger exchanges heat with the core in the downstream region of the flow.
FIG. 5 is an explanatory diagram showing the heat transfer of the heat exchange medium 21 circulating in the core using the corrugated fin 5 having no pattern formed on the surfaces of the rising surface 6b and the rising surface 6c as a core.
The heat 24 generated from the heat exchange object 20 arranged in the upstream region of the flow of the heat exchange medium 21 (point B in FIG. 5A) is a corrugated connected to the heat exchange object 20 via a top plate 2 (not shown). Heat is transferred to the heat exchange medium 21 circulating in the vicinity of the ridge line portion 6a of the fin 5 (see FIG. 5B). Of the flow of the heat exchange medium 21, the heat-received medium 21a that has received heat 24 flows through the top plate 2 side as it is, and reaches the downstream region (point D in FIG. 5A) of the flow of the heat exchange medium 21. When it reaches the temperature, the temperature rises due to heat exchange, so that the action of receiving heat from the heat exchange object 20 arranged in the downstream region is reduced.
As a result, heat dissipation of the heat exchange object located in the downstream region of the flow of the heat exchange medium 21 is hindered, and the temperature of the heat exchange object at that position increases. Of the flow of the heat exchange medium 21, the unreceived heat medium 21b that has not received heat 24 flowing at a position away from the top plate 2 passes through the flow path in the corrugated fin 5 as it is and is discharged from the outlet 23. To.
In this embodiment, in order to solve the above problem, it has the following structure.
On the surfaces of the rising surface 6b and the rising surface 6c of the corrugated fin 5 constituting the core, a pattern of uneven stripes 10 in which convex portions 10a and concave portions 10b are alternately formed in a wavy shape in the thickness direction of the strip-shaped metal plate is formed. There is. The pattern of the uneven stripes 10 is formed on the rising surface 6b and the rising surface 6c except for the vicinity of the ridge line portion 6a of the corrugated fin 5.
The uneven strip 10 has an inclination angle θ of 10 to 60 degrees with respect to the mainstream of the heat exchange medium 21, and the adjacent convex portions 10a and concave portions 10b are inclined in the same direction. The inclination angles of the uneven strips 10 of the rising surface 6b and the rising surface 6c are also inclined in the same direction. Further, in this embodiment, as shown in FIG. 3, the inclination of the uneven strip 10 decreases in the lower right direction (moves away from the heat exchange object 20) as the mainstream of the heat exchange medium 21 goes from the upstream to the downstream. Is formed in.
As shown in FIG. 4A, the heat exchange medium 21 in the flow path of the corrugated fin 5 receives heat 24 at the upstream position of the heat exchange medium 21 (point B in FIG. 4A) and has received heat. It becomes the medium 21a. The heat-received medium 21a exchanges heat with the heat exchange target 20 while moving from the top plate 2 side to the bottom plate 3 side along the groove portions 10c formed on the

surfaces

6b and 6c. The groove portion 10c is separated from the groove portion 10c at the position (point D in FIG. 4A) of the ridge line portion 6a (the ridge line portion 6a connected to the bottom plate plate 3) where the inclined groove portion 10c disappears.
On the other hand, the unreceived heat medium 21b that has not exchanged heat with the heat exchange object 20 outside the groove portion 10c in the flow path flows into the groove portion 10c as shown in FIG. 4C, and is shown in FIG. 4 (C). At point D in A), the heat-received medium 21a is replaced. By circulating the flows of the

media

21a and 21b between the top plate 2 side and the bottom plate 3 side, heat exchange can be performed with the heat exchange object 20 on the downstream side of the heat exchange medium 21. become able to. As a result, deterioration of the heat exchange performance of the entire heat exchanger is suppressed.
FIG. 6 shows a heat exchanger using a corrugated fin 5 having the pattern of the uneven streaks 10 of the present invention of FIG. The comparison of the thermal resistance with the heat exchanger using the above is shown.
The horizontal axis of the graph of FIG. 6 is the heat exchange object 20 arranged on the inlet side 20a (Inlet side), the intermediate portion 20b (Middle), and the outlet side 20c (Outlet side) of the heat exchange medium 21 in FIG. Each part is shown. In one heat exchange object 20, there are two heat-generating parts along the flow of the heat-exchange medium 21, and the six heat-generating parts are shown.
The vertical axis of the graph of FIG. 6 shows the thermal resistance (° C./W) at each site.
The experimental conditions are that the heat exchange medium 21 is water, the flow rate Vw is 6 L / min, the water inlet temperature Tw1 is 70 ° C., and the amount of heat input at each of the six locations is 300 W.
From the contents described in FIG. 6, the heat exchanger using the corrugated fin 5 having the pattern of the uneven stripes 10 of the present invention (the uneven stripes 10 has a downward-sloping inclined pattern) is the corrugated fin 5 in which the pattern is not formed. The heat dissipation characteristics are better in various places than the heat exchanger using.
Further, when the thermal resistance on the inlet 22 side is 100, the ratio of the thermal resistance on the outlet 23 side uses the corrugated fin 5 having the pattern of the uneven stripes 10 of the present invention (the uneven stripes 10 have a downward-sloping inclined pattern). The heat exchanger is 127.1 (the difference in ratio is 27.1%), while the heat exchanger using the corrugated fin 5 without a pattern is 134.8 (the difference in ratio is 34). 0.8%), and the heat exchanger of the present invention has a smaller rate of deterioration in heat dissipation characteristics on the outlet 23 side.
Even if the above experimental conditions are changed, the absolute value indicated by the thermal resistance value in the graph of FIG. 6 changes, but the tendency indicated by the value does not change.
Next, FIG. 7 shows a second embodiment of the corrugated fin 5 used in the heat exchanger of the present invention, and describes the heat transfer of the heat exchange medium 21 circulating inside the corrugated fin 5.
This example differs from the example of FIG. 4 in that the pattern of the uneven stripes 10 is formed at an inclination angle rising to the right from the bottom plate plate 3 side to the top plate plate 2 side.
This example will also be described under the condition that the heat exchange object is attached to the top plate 2 side.
In this case, as shown in FIG. 7A, the unreceived heat medium 21b that has not exchanged heat with the heat exchange object 20 goes downstream along the groove portion 10c that is inclined upward to the right, so that the top plate 2 Move to the side. At point D in FIG. 7A, the heat-received medium 21a is replaced.
FIG. 8 shows a heat exchanger using the corrugated fin 5 having the pattern of the first embodiment of FIG. 4 (the uneven stripe 10 is inclined downward to the right with respect to the mainstream direction of the heat exchange medium 21), and FIG. The comparison of the heat resistance with the heat exchanger using the corrugated fin 5 having the pattern of the second embodiment (the uneven stripe 10 is inclined upward to the right with respect to the mainstream direction of the heat exchange medium 21) is shown. ..
The description of the horizontal axis and the vertical axis of the graph is the same as in FIG. 6, and is omitted. The experimental conditions are the same as in FIG.
As shown in FIG. 8, even if the pattern-formed one of the second embodiment is used, the heat exchange medium 21 is circulated and the heat dissipation performance is improved as compared with the corrugated fin 5 in which the pattern is not formed.
However, the heat dissipation characteristics are higher when the pattern of the first embodiment is used.
Even if the above experimental conditions are changed, the absolute value indicated by the thermal resistance value in the graph of FIG. 8 changes, but the tendency indicated by the value does not change.
As described above, the present invention proposes to improve the heat dissipation characteristics of the entire heat exchanger by circulating the heat-received medium 21a and the non-heat-received medium 21b of the heat exchange medium 21. In general, increasing the degree of circulation improves the heat dissipation characteristics. However, as the pressure loss due to circulation increases, a decrease in the flow rate is also caused at the same time, which causes a decrease in heat dissipation characteristics.
The following items are examined to the extent that the above causes can be sufficiently avoided. In other words, the optimum value of the heat dissipation characteristic improvement allowance taking into account the pressure loss with respect to the degree of circulation was found by numerical calculation.
Assuming that the circulation degree of the heat exchange medium 21 is N, the volume of the pattern of the uneven stripes 10 is Vwave, and the volume of one wave 6 is Vcell, the circulation degree N can be expressed by the following equation.
(Equation 1)
N = (Vwave) / (Vcell)
Assuming that the cross-sectional area of the pattern of the uneven strip 10 is Swave (see FIG. 3C) and the cross-sectional area of one wave 6 is Cell (see FIG. 3C), Vwave and Vcell are as follows, respectively. It can be expressed by an expression.
(Equation 2)
Vwave = Swave × (length of uneven stripe 10 pattern) × (number of convex portions 10a and concave portions 10b) × 2
= (Wp × sinθ × Wh / 2) × (B / sinθ) × (L / Wp) × 2
= Wh x B x L
(Equation 3)
Vcell = Cell × L
= (A x B) x L
Here, Wp is the pitch of the pattern of the uneven stripes 10, Wh is the height of the pattern of the uneven stripes 10, θ is the inclination angle of the pattern of the uneven stripes 10, A is the average width of one wave 6, and B is one wave. The height of 6 and L are the flow path lengths.
By substituting (Equation 2) and (Equation 3) into (Equation 1) and rearranging them, the degree of circulation N becomes (Equation 4).
(Equation 4)
N = Wh / A
FIGS. 9 (a) and 9 (b) show the results of confirming the dependence of the footprint heat transfer coefficient and the pressure loss on the degree of circulation (N), which are heat dissipation characteristic indexes, by thermo-fluid analysis.
FIG. 9C shows a heat dissipation characteristic index considering the pressure loss with the circulation degree (N) as a function.
The horizontal axes of (a), (b), and (c) in FIG. 9 each have a degree of circulation N.
The vertical axis of FIG. 9A is the footprint heat of the present invention when the heat transfer coefficient of the heat exchanger using the corrugated fin 5 having no pattern (hereinafter referred to as a comparison target) is 1. Take the transmission rate ratio (arb.unit). The vertical axis of FIG. 9B takes a pressure drop index (arb.unit). The vertical axis of FIG. 9C takes a heat dissipation characteristic index (arb.unit) in consideration of pressure loss. The solid line of each graph is the present invention, and the alternate long and short dash line indicates the comparison target. The experimental conditions are the same as in FIG.
In FIG. 9A, when the degree of circulation (N) increases, the heat dissipation characteristics improve, but when the degree of circulation (N) exceeds a certain value, the rate of increase gradually decreases. On the other hand, in FIG. 9B, the pressure loss increases uniformly.
When the degree of circulation (N) in FIG. 9 (c) is in the range of 0 to 0.3, the rate of increase in heat dissipation characteristics is larger than the rate of increase in pressure loss, so the heat dissipation performance index considering the pressure loss is the degree of circulation. It improves with the increase of (N).
On the other hand, in the range where the degree of circulation (N) exceeds 0.3, the increase rate of the pressure loss exceeds the increase rate of the heat dissipation characteristic, so that the heat dissipation characteristic index considering the pressure loss decreases. It can be inferred that this is because the footprint heat transfer coefficient decreases due to the decrease in the flow rate due to the increase in pressure loss.
From the above, it was found that the improvement of heat dissipation characteristics in consideration of the pressure loss shows the maximum value when the circulation degree (N) is 0.3.
As can be seen from FIG. 9 (C), the circulation degree (N) has a heat dissipation characteristic value of 50% or more of the maximum value in the range of the equation 5.
(Equation 5)
0.1 ≤ N ≤ 0.8
Further, the degree of circulation (N) is within the range of the formula 6, and the value of the heat dissipation characteristic is 75% or more of the maximum value.
(Equation 6)
0.15 ≤ N ≤ 0.68
In the first embodiment and the second embodiment of the present invention, the effect of the corrugated fin 5 on the heat exchanger in which the heat exchange object 20 is attached only to one side of the top plate 2 will be described. However, the same can be said even when the heat exchange object 20 is attached to only one side of the bottom plate plate 3.
Further, as shown in FIG. 10, the same effect can be obtained even when the heat exchange target 20 is attached to both sides of the top plate 2 and the bottom plate 3.

1 Heat exchanger body 2 Top plate plate 3 Bottom plate plate 4 Peripheral wall part 5 Corrugated fin 6 Wave 6a Ridge line part 6b Rising surface 6c Standing bottom surface 10 Concavo-convex strip 10a Convex part 10b Concave part 10c Groove part 20 Heat exchange object 20a Inlet side 20b Intermediate part 20c Outlet side 21 Heat exchange medium 21a Heat received medium 21b Unheated medium 22 Inlet 23 Outlet 24 Heat

Claims

A box-shaped heat having a pair of top plate plates (2) and bottom plate plates (3) facing each other at a distance, and a peripheral wall portion (4) covering the outer periphery of the pair of plates (2, 3). The exchanger body (1) is formed, and the inner fin is interposed inside the heat exchanger body (1).
The inner fin is a corrugated fin (5) in which a strip-shaped metal plate is folded back into a corrugated shape.
The ridge portion (6a) of each wave (6) of the corrugated fin (5) is joined to the pair of plates (2, 3), and at least one of the pair of plates (2, 3) is attached. The heat exchange object (20) is attached to the opposite surface of the fin joint surface of the
A heat exchanger in which a heat exchange medium (21) flows inside the heat exchanger body (1) along the wave ridge direction of the corrugated fins (5) and exchanges heat with the heat exchange object (20). In
Concavo-convex stripes (10) are alternately formed on the rising surface (6b) and the rising surface (6c) of each wave (6) in the thickness direction of the strip-shaped metal plate.
Each of the uneven strips (10) has an inclination angle of 10 to 60 degrees with respect to the mainstream of the heat exchange medium (21), and the adjacent uneven strips (10) are arranged in the same direction as a heat exchanger. ..
In the heat exchanger according to claim 1,
When the heat exchange object (20) is attached to only one of the pair of plates (2, 3) joined to the ridge line portion (6a) of the corrugated fin (5).
A heat exchanger formed so that the uneven strips (10) move away from the heat exchange object (20) as the uneven strips (10) move from the upstream to the downstream of the mainstream of the heat exchange medium (21).
In the heat exchanger according to claim 1 or 2.
Let A be the distance between the adjacent surfaces (6b, 6c) of each wave (6) of the corrugated fin (5).
When the height of the unevenness of the uneven strip (10) is Wh,
A heat exchanger characterized in that the value of Wh / A is 0.1 or more and 0.8 or less.
In the heat exchanger according to claim 3,
A heat exchanger characterized in that the value of Wh / A is 0.15 or more and 0.68 or less.