WO2020184315A1 - Heat exchanger - Google Patents

Abstract

This heat exchanger comprises a fin (23) accommodated inside a tube (21). The fin has: joining parts (230a, 230b, 230c) that are folded in a wave shape at a prescribed fin pitch, the joining parts being such that the distal-end parts of the folded portions are joined to the inner surface of the tube; and non-joining parts (231a, 231b) that are not joined to the inner surface of the tube, the non-joining parts being formed longer than the prescribed fin pitch. In the tube, protruding parts (210a, 211a) are formed on outer wall surfaces (210, 211) facing the non-joining parts.

Description

Heat exchanger Cross-reference of related applications

This application is based on Japanese Patent Application No. 2019-045425 filed on March 13, 2019 and Japanese Patent Application No. 2020-021446 filed on February 12, 2020. , Which asserts the benefit of its priority, and the entire contents of its patent application are incorporated herein by reference.

This disclosure relates to heat exchangers.

Conventionally, there is a heat exchanger described in Patent Document 1 below. The heat exchanger described in Patent Document 1 is a condenser and includes a plurality of tubes arranged in a laminated manner. Refrigerant is flowing inside the tube. Air is flowing in the gap between adjacent tubes. In this heat exchanger, the refrigerant is condensed by heat exchange between the refrigerant flowing inside each tube and the air flowing outside each tube. Inner fins are housed inside the tube. The inner fin is a so-called corrugated fin formed by bending a thin metal plate in a wavy shape. The inner fin has a function of promoting heat exchange between the refrigerant and air by increasing the heat transfer area with respect to the refrigerant.

Japanese Unexamined Patent Publication No. 2013-217507

The structure described in Patent Document 1, specifically, the structure in which the inner fin is provided inside the tube is not limited to the condenser, but is not limited to the condenser, but is used for a radiator that cools the cooling water by radiating the heat of the cooling water to the air. It is valid even when applied. However, when a structure in which an inner fin is provided inside the tube is adopted for the radiator, there are the following concerns.

In recent years, vehicles traveling with an electric motor as a power source are equipped with a radiator for cooling the cooling water circulating in the battery and its peripheral devices that supply electric power to the electric motor, in addition to the radiator for cooling the engine cooling water. In some cases. Such a radiator is sometimes referred to as a low water temperature radiator because cooling water having a temperature lower than that of the engine cooling water flows through the radiator. In a low water temperature radiator, the flow rate of the cooling water supplied from the electric pump may be smaller than that of the engine cooling water radiator, so the flow of the cooling water inside the tube becomes a flow in the low Re (Reynolds) number region. There is a risk that the heat transfer coefficient of the cooling water will decrease. Therefore, if an inner fin is provided inside the tube as in the heat exchanger described in Patent Document 1, the heat transfer area for the cooling water can be increased, so that the heat transfer coefficient of the cooling water can be improved. Is possible.

By the way, when the inner fin is provided inside the tube, the inner fin becomes an obstacle to the flow of the cooling water, so that the water flow resistance of the cooling water increases. Further, when a low water temperature radiator is mounted on a vehicle, it may be necessary to reduce the number of stacking stages of the radiator tubes due to the relationship between the space limitation of the vehicle and the heat generation amount of the radiator. As the number of stacked tubes decreases, the flow velocity of the cooling water in the tube increases, so that the water flow resistance of the cooling water further increases. When the water flow resistance of the cooling water increases, it becomes difficult for the cooling water to flow in the tube, so that the heat transfer coefficient of the low water temperature radiator may decrease. This is one of the factors that cannot improve the heat transfer coefficient of the low water temperature radiator even though the inner fin is provided inside the tube.

It should be noted that such a problem is not limited to the low water temperature radiator, but is a problem common to heat exchangers that exchange heat between the fluid flowing inside the tube and the fluid flowing outside the tube.
An object of the present disclosure is to provide a heat exchanger capable of achieving both a reduction in water flow resistance and an improvement in heat transfer coefficient.

The heat exchanger according to one aspect of the present disclosure has a plurality of tubes arranged in a laminated manner, and heat exchange is performed between a first fluid flowing inside the tubes and a second fluid flowing outside the tubes. It is said. The heat exchanger includes fins housed inside the tube. The fins are a joint portion that is bent in a wavy shape at a predetermined fin pitch and the tip of the bent portion is joined to the inner surface of the tube, and a portion formed longer than the predetermined fin pitch. It has a non-joint portion that is not joined to the inner surface. A protrusion is formed on the outer wall of the tube facing the non-joint portion.

According to this configuration, since the non-joint portion of the fin is not in contact with the inner surface of the tube, it is possible to secure the cross-sectional area of the flow path through which the first fluid flows. Therefore, it is possible to reduce the water flow resistance. In addition, the protrusions formed on the tube increase the heat transfer area of the tube with respect to the first fluid, so that the heat transfer coefficient of the heat exchanger can be improved.

Further, another heat exchanger according to one aspect of the present disclosure has a plurality of tubes arranged in a laminated manner, and is located between a first fluid flowing inside the tubes and a second fluid flowing outside the tubes. Heat exchange takes place. The heat exchanger includes fins housed inside the tube. The fins are a joint portion that is bent in a wavy shape at a predetermined fin pitch and the tip of the bent portion is joined to the inner surface of the tube, and a portion formed longer than the predetermined fin pitch. It has a non-joint portion that is not joined to the inner surface. A protrusion is formed on the non-joint portion.

According to this configuration, since the non-joint portion of the fin is not in contact with the inner surface of the tube, it is possible to secure the cross-sectional area of the flow path through which the first fluid flows. Therefore, it is possible to reduce the water flow resistance. Further, since the heat transfer area of the fin to the first fluid is increased by the protrusion formed in the non-joint portion of the fin, the heat transfer rate of the heat exchanger can be improved.

Further, another heat exchanger according to one aspect of the present disclosure has a plurality of tubes arranged in a laminated manner, and between a first fluid flowing inside the tubes and a second fluid flowing outside the tubes. Heat exchange takes place. The heat exchanger includes fins housed inside the tube. The fins are a joint portion that is bent in a wavy shape at a predetermined fin pitch and the tip of the bent portion is joined to the inner surface of the tube, and a portion formed longer than the predetermined fin pitch. It has a non-joint portion that is not joined to the inner surface. A protrusion is formed on the outer wall of the tube facing the non-joint portion. A protrusion is formed on the non-joint portion.

According to this configuration, since the non-joint portion of the fin is not in contact with the inner surface of the tube, it is possible to secure the cross-sectional area of the flow path through which the first fluid flows. Therefore, it is possible to reduce the water flow resistance. Further, since the protrusion formed on the tube and the protrusion formed on the non-joint portion of the fin increase the heat transfer area of the tube and fin with respect to the first fluid, the heat transfer coefficient of the heat exchanger can be increased. Can be improved.

FIG. 1 is a front view showing the front structure of the heat exchanger of the first embodiment. FIG. 2 is a cross-sectional view showing a cross-sectional structure taken along the line II-II of FIG. FIG. 3 is a cross-sectional view showing a cross-sectional structure of the tube of the first embodiment. FIG. 4 is a perspective view showing a cross-sectional perspective structure of the tube of the first embodiment. FIG. 5 is a graph showing the relationship between the Reynolds number Re of the cooling water and the heat transfer coefficient α. FIG. 6 is a cross-sectional view showing the cross-sectional structure of the tube of the first modification of the first embodiment. FIG. 7 is a perspective view showing a cross-sectional perspective structure of the tube of the first modification of the first embodiment. FIG. 8 is a cross-sectional view showing a cross-sectional structure of the tube of the second embodiment. FIG. 9 is a cross-sectional view showing the cross-sectional structure of the tube of the first modification of the second embodiment. FIG. 10 is a cross-sectional view showing the cross-sectional structure of the tube of the first modification of the second embodiment. FIG. 11 is a perspective view showing a cross-sectional perspective structure of the tube of the second modification of the second embodiment. 12 (A) and 12 (B) are cross-sectional views showing a cross-sectional structure around a protrusion in a tube of a second modification of the second embodiment. FIG. 13 is a diagram schematically showing a flow mode of cooling water in a tube in the heat exchanger of the second modification of the second embodiment. FIG. 14 is a perspective view showing a cross-sectional perspective structure of the tube of the third modification of the second embodiment. 15 (A) and 15 (B) are cross-sectional views showing a cross-sectional structure around a protrusion in a tube of a third modification of the second embodiment. FIG. 16 is a perspective view showing a cross-sectional perspective structure of the tube of the fourth modification of the second embodiment. 17 (A) and 17 (B) are cross-sectional views showing a cross-sectional structure around a protrusion in a tube of a fourth modification of the second embodiment. FIG. 18 is a cross-sectional view showing the cross-sectional structure of the tube of another embodiment. FIG. 19 is a cross-sectional view showing a cross-sectional structure of a tube of another embodiment.

Hereinafter, embodiments of the heat exchanger will be described with reference to the drawings. In order to facilitate understanding of the description, the same components are designated by the same reference numerals as much as possible in each drawing, and duplicate description is omitted.
<First Embodiment>
First, the heat exchanger 10 of the first embodiment shown in FIG. 1 will be described. The heat exchanger 10 shown in FIG. 1 is mounted on a vehicle equipped with an engine and an electric motor as a power source for traveling. The heat exchanger 10 circulates engine cooling water for cooling the engine and cooling water for cooling the electric motor and its peripheral devices. Since the cooling water for cooling the electric motor and its peripheral devices is lower than the engine cooling water, it will be referred to as "low temperature cooling water" below. The heat exchanger 10 can cool the engine cooling water and the low temperature cooling water by exchanging heat between the engine cooling water and the air and exchanging heat between the low temperature cooling water and the air. It is a complex type radiator. In the present embodiment, the engine cooling water and the low temperature cooling water correspond to the first fluid, and the air corresponds to the second fluid. In the following, for convenience, the engine cooling water and the low temperature cooling water are collectively referred to as "cooling water". The heat exchanger 10 is arranged in the engine room together with the condenser and the evaporator of the vehicle air conditioner. For example, in the case of combination with the evaporator of the vehicle air conditioner, the heat exchanger 10 is arranged at a position closer to the grill opening than the condenser of the vehicle air conditioner. Air introduced from the grill opening is supplied to the heat exchanger 10.

As shown in FIG. 1, the heat exchanger 10 includes a core portion 20, a first header tank 30, and a second header tank 40.
The core portion 20 includes a plurality of tubes 21 and a plurality of outer fins 22.

The plurality of tubes 21 are stacked and arranged at predetermined intervals in the direction indicated by the arrow Z. The tube 21 is formed so as to extend in the direction indicated by the arrow X. The cross-sectional shape of the tube 21 orthogonal to the direction indicated by the arrow X is formed in a flat tubular shape. Inside the tube 21, a flow path through which the cooling water flows is formed so as to extend in the direction indicated by the arrow X. Air flows in the direction indicated by the arrow Y in the gap between the adjacent tubes 21 and 21.

Hereinafter, the direction indicated by the arrow X is referred to as "tube longitudinal direction X", the direction indicated by the arrow Y is referred to as "air flow direction Y", and the direction indicated by the arrow Z is referred to as "tube stacking direction Z". .. In this embodiment, the tube stacking direction Z is the vertical direction, and the tube longitudinal direction X and the air flow direction Y are the horizontal directions. Therefore, the heat exchanger 10 of the present embodiment is a so-called cross-flow type heat exchanger.

The outer fins 22 are arranged in the gap between the adjacent tubes 21 and 21. The outer fin 22 is a so-called corrugated fin formed by bending a thin metal plate made of aluminum or the like in a wavy shape. The tip of the bent portion of the outer fin 22 is in contact with the outer surfaces of the adjacent tubes 21 and 21, and the contact portions are joined by brazing. The outer fin 22 is fixed to the tube 21 by this joining structure. The outer fin 22 has a function of promoting heat exchange between the refrigerant flowing inside the tube 21 and the air by increasing the heat transfer area for the air flowing between the adjacent tubes 21 and 21. ..

The first header tank 30 is connected to one end of each tube 21. The first header tank 30 is formed in a tubular shape. Inside the first header tank 30, a partition portion 33 that partitions the internal space into the first distribution flow path 31 and the second distribution flow path 32 is formed. The first header tank 30 is provided with the first inflow port 310 corresponding to the portion where the first distribution flow path 31 is formed, and the second header tank 30 corresponds to the portion where the second distribution flow path 32 is formed. An inflow port 320 is provided.

The second header tank 40 is connected to the other end of each tube 21. The second header tank 40 is formed in a tubular shape like the first header tank 30. Inside the second header tank 40, a partition portion 43 for partitioning the internal space into the first collecting flow path 41 and the second collecting flow path 42 is formed. The partition portion 43 of the second header tank 40 is arranged at the same position as the position of the partition portion 33 of the first header tank 30 in the tube stacking direction Z. The second header tank 40 is provided with a first discharge port 410 corresponding to a portion where the first collecting flow path 41 is formed, and corresponds to a portion where the second collecting flow path 42 is formed. A second discharge port 420 is provided.

In the following, the region of the core portion 20 connected to the first distribution flow path 31 of the first header tank 30 and the first assembly flow path 41 of the second header tank 40 is referred to as the first core region A1 and is referred to as the core. The region connected to the second distribution flow path 32 of the first header tank 30 and the second assembly flow path 42 of the second header tank 40 in the unit 20 is referred to as a second core region A2. As shown in FIG. 1, in the heat exchanger 10 of the present embodiment, the first core region A1 is larger than the second core region A2.

In this heat exchanger 10, engine cooling water flows into the first inflow port 310 of the first header tank 30. The engine cooling water that has flowed into the first inflow port 310 is distributed from the first distribution flow path 31 of the first header tank 30 to each tube 21 of the first core region A1 of the core portion 20. In the first core region A1 of the core portion 20, the engine cooling water is cooled by heat exchange between the engine cooling water flowing inside each tube 21 and the air flowing outside each tube. The engine cooling water cooled by flowing through each tube is collected in the first collecting flow path 41 of the second header tank 40, and then discharged from the first discharge port 410 of the second header tank 40.

Further, in this heat exchanger 10, low water temperature cooling water flows into the second inflow port 320 of the first header tank 30. The low water temperature cooling water that has flowed into the second inflow port 320 is distributed from the second distribution flow path 32 of the first header tank 30 to each tube 21 of the second core region A2 of the core portion 20. In the second core region A2 of the core portion 20, the low water temperature cooling water is cooled by heat exchange between the low water temperature cooling water flowing inside each tube 21 and the air flowing outside each tube. .. The low water temperature cooling water cooled by flowing through each tube is collected in the second collecting flow path 42 of the second header tank 40, and then discharged from the second discharge port 420 of the second header tank 40.

Next, the structure of the core portion 20 will be specifically described.
As shown in FIG. 2, in the core portion 20, the laminated structure of the tubes 21 is arranged in two rows in the air flow direction Y. The core portion 20 is not limited to a structure having two rows of laminated structures of tubes 21, and may have a structure having only one row of laminated structures of tubes 21.

The inner fin 23 is housed inside the tube 21. The inner fin 23 is formed by bending a thin metal plate such as aluminum.
As shown in FIGS. 3 and 4, a crimped portion 232 to be crimped to the tube 21 is formed at one end of the inner fin 23. The crimped portion 232 increases the thickness of one end of the tube 21 to ensure the stone chipping performance of the tube 21.

Joint portions 230a to 230c bent in a wavy shape at a predetermined fin pitch FP are formed in the inner portion of the inner fin 23, which is inside the crimped portion 232, and in the central portion and the other end portion of the inner fin 23, respectively. The tip of the bent portion of the joint portions 230a to 230c is in contact with the inner surface of the tube 21. The contact parts are joined by brazing. The joint portions 230a to 230c position the inner fin 23 with respect to the tube 21 and secure heat transfer to the tube 21 and rigidity of the tube 21.

A non-joint portion 231a that is not joined to the inner surface of the tube 21 is formed in a portion of the inner fin 23 between the joint portion 230a and the joint portion 230b. Similarly, a non-joint portion 231b is also formed in a portion of the inner fin 23 between the joint portion 230b and the joint portion 230c. The non-joining portions 231a and 231b are formed so as to extend parallel to the inner surface of the tube 21. The respective lengths L1 and L2 of the non-joining portions 231a and 231b are longer than the respective fin pitch FPs of the joining portions 230a to 230c.

A plurality of protrusions 210a and 211a are formed on the tube 21 so as to project inward of the tube 21 at a portion of the inner fin 23 facing the non-joining portions 231a and 231b. More specifically, a first protrusion 210a is formed on one outer wall 210 of the tube 21 facing the non-joining portion 231a of the inner fin 23. A second protrusion 211a is formed on the other outer wall 211 of the tube 21 facing the non-joining portion 231a of the inner fin 23. The first protrusion 210a is arranged at a position closer to the joint 230a than the joint 230b of the inner fin 23. The second protrusion 211a is arranged at a position closer to the joint 230b than the joint 230a of the inner fin 23. Similarly, the first protrusion 210a and the second protrusion 211a are formed on the outer wall portions 210 and 211 of the tube 21 facing the non-joint portion 231b of the inner fin 23, respectively. The space partitioned by the joint portions 230a and 230b of the inner fin 23, the non-joint portions 231a, and the outer wall portions 210 and 211 of the tube 21 is defined as the first space S1, and the joint portions 230b, 230c and non-joint portions 231b of the inner fin 23, When the space partitioned by the outer wall portions 210 and 211 of the tube 21 is the second space S2, the first space S1 and the second space S2 are spaces having substantially the same shape.

Next, an operation example of the heat exchanger 10 of the present embodiment will be described.
In the heat exchanger 10 of the present embodiment, the Reynolds number Re of the cooling water flowing through the tube 21 and the heat transfer coefficient α of the cooling water change as shown by the solid line L1 in FIG. In FIG. 5, as a reference example, the Reynolds number Re and the heat transfer of the cooling water when the protrusions 210a and 211a are not formed on the tube 21 and the inner fin 23 is not provided inside the tube 21. The relationship with the rate α is shown by the alternate long and short dash line L2. Further, in FIG. 5, as a reference example, the Reynolds number Re and the heat transfer of the cooling water when the protrusions 210a and 211a are formed on the tube 21 and the inner fin 23 is not provided inside the tube 21. The relationship with the rate α is shown by the alternate long and short dash line L3.

As shown in FIG. 5, when the value of the Reynolds number Re is small, the flow of the cooling water becomes a laminar watershed. Further, when the value of the Reynolds number Re is large, the flow of the cooling water becomes a turbulent flow area. When the value of the Reynolds number Re is an intermediate value between them, the flow of the cooling water becomes a transition region. The transition region is a region where the flow of cooling water transitions between the laminar watershed and the turbulent watershed.

When the protrusions 210a and 211a are formed on the tube 21, but the inner fin 23 is not provided inside the tube 21, the flow of the cooling water flows as shown by the alternate long and short dash line L3 in FIG. The heat transfer coefficient α of the cooling water can be secured in the transition region and the turbulent flow region. However, when the flow of the cooling water is in the laminar basin, there is a possibility that the heat transfer rate α of the cooling water cannot be sufficiently secured. The flow rate of the low temperature cooling water flowing through the second core region A2 of the heat exchanger 10 is lower than the flow rate of the engine cooling water flowing through the first core region A1. Therefore, since the flow of the low-temperature cooling water flowing through the second core region A2 of the heat exchanger 10 tends to be a layered basin, the heat transfer coefficient α of the cooling water can be sufficiently obtained only by forming the protrusions 210a and 211a on the tube 21. It may not be possible to secure it.

In this regard, in the heat exchanger 10 of the present embodiment, as shown by the solid line L1 in FIG. 5, as compared with the reference example of the alternate long and short dash line L3, the heat of the cooling water when the flow of the cooling water is in the laminar basin. It is possible to improve the transmission rate α. This is because in the heat exchanger 10 of the present embodiment, the heat transfer area can be increased and the heat transfer can be promoted by the inner fins 23 provided inside the tube 21.

Further, in the heat exchanger 10 of the present embodiment, as shown by the solid line L1 in FIG. 5, as compared with the reference example of the alternate long and short dash line L3, the heat of the cooling water is generated even when the flow of the cooling water is in the transition region. It is possible to improve the transmission rate α. This is because, in addition to the effects of the protrusions 210a and 211a themselves, the inner fins 23 can increase the heat transfer area and promote heat transfer.

According to the heat exchanger 10 of the present embodiment described above, the actions and effects shown in the following (1) to (3) can be obtained.
(1) Since the non-joined portions 231a and 231b of the inner fin 23 are not in contact with the inner surface of the tube 21, it is possible to secure the cross-sectional area of the flow path through which the engine cooling water and the low temperature cooling water flow. Therefore, it is possible to reduce the water flow resistance. Further, the protrusions 210a and 211a formed on the tube 21 increase the local heat transfer area of the tube 21 with respect to the cooling water, and the turbulence around the protrusions of the cooling water causes the heat exchanger 10 to flow. The heat transfer coefficient can be improved.

(2) The protrusions 210a and 211a are formed so as to protrude inward of the tube 21. According to such a configuration, it is possible to avoid interference between the protrusions 210a and 211a and the outer fins 22.
(3) The non-joining portions 231a and 231b of the inner fin 23 are formed so as to extend parallel to the inner surface of the tube 21. According to such a configuration, a flow path having a predetermined width can be secured between the inner surface of the tube 21 and the non-joining portions 231a and 231b of the inner fin 23, so that the cooling water flowing through the tube 21 can pass through. It is possible to further reduce the water resistance.

(First modification)
Next, a first modification of the heat exchanger 10 of the first embodiment will be described.
As shown in FIG. 6, the tube 21 of this modified example is formed so that the protrusions 210a and 211a project outward.

According to such a configuration, the air flowing between the adjacent tubes 21 and 21 collides with the protrusions 210a and 211a, so that the air flow direction around the outside of the tubes can be changed. Therefore, since it is possible to promote the introduction of air into the louver portion formed on the outer fin 22, it is possible to promote the improvement of the heat exchange performance on the air side by the protrusions 210a and 211a.

(Second modification)
Next, a second modification of the heat exchanger 10 of the first embodiment will be described.
As shown in FIG. 7, the protrusions 210a and 211a of this modification are formed not in a hemispherical shape but in an elongated hole shape that intersects diagonally with respect to the flow direction of the cooling water. According to such a configuration, it is possible to minimize the gap formed on the joint surface between the protrusions 210a and 211a and the outer fin 22. As a result, the joint area between the tube 21 and the outer fin 22 is increased, so that the heat exchange performance on both the cooling water side and the air side can be improved.

<Second Embodiment>
Next, the heat exchanger 10 of the second embodiment will be described. Hereinafter, the differences from the heat exchanger 10 of the first embodiment will be mainly described.
As shown in FIG. 8, in the heat exchanger 10 of the present embodiment, a plurality of protrusions 232a are formed on the non-joined portions 231a and 231b of the inner fin 23. The protrusion 232a is formed so as not to come into contact with the inner surface of the tube 21. The arrangement of the protrusion 232a in the non-joining portion 231a and the arrangement of the protrusion 232a in the non-joining portion 231b are substantially the same. As a result, the space partitioned by the joint portions 230a and 230b of the inner fin 23, the non-joint portions 231a, and the outer wall portions 210 and 211 of the tube 21 is designated as the first space S1, and the joint portions 230b and 230c of the inner fin 23 are not joined. When the space partitioned by the portions 231b and the outer wall portions 210 and 211 of the tube 21 is the second space S2, the first space S1 and the second space S2 have substantially the same shape.

According to the heat exchanger 10 of the present embodiment described above, in addition to the action and effect shown in (3) above, the action and effect shown in (4) below can be obtained.
(4) Since the non-joined portions 231a and 231b of the inner fin 23 are not in contact with the inner surface of the tube 21, it is possible to secure the cross-sectional area of the flow path through which the engine cooling water and the low temperature cooling water flow. Therefore, it is possible to reduce the water flow resistance. Further, since the protrusion 232a formed on the inner fin 23 increases the heat transfer area of the inner fin 23 with respect to the cooling water, the heat transfer coefficient of the heat exchanger 10 can be improved. It is desirable that all the protrusions 232a do not come into contact with the inner surface of the tube 21, but a part of the protrusions 232a is a part of the tube 21 as long as the same or similar effect as the heat exchanger 10 of the present embodiment can be obtained. It may be in contact with the inner surface of the.

(First modification)
Next, a first modification of the heat exchanger 10 of the second embodiment will be described.
As shown in FIG. 9, in the heat exchanger 10 of this modified example, the protrusion 232a is formed by cutting up a part of the non-joining portions 231a and 231b of the inner fin 23 into a trapezoidal shape. The cut-up shape of the protrusion 232a is not limited to the trapezoidal shape, and may be triangular, for example, as shown in FIG.

According to such a configuration, it is possible to easily form the protrusion 232a on the inner fin 23.
(Second modification)
Next, a second modification of the heat exchanger 10 of the second embodiment will be described. In the following, as shown in FIG. 11, one of the tube longitudinal directions X is referred to as the X1 direction, and the other direction is referred to as the X2 direction. Further, one of the air flow directions Y is referred to as the Y1 direction, and the other direction is referred to as the Y2 direction. Further, one of the tube stacking directions Z is referred to as the Z1 direction, and the other direction is referred to as the Z2 direction. The X2 direction corresponds to the flow direction of the cooling water.

As shown in FIG. 11, in the heat exchanger 10 of this modified example, protrusions 232b and 232c are formed on the non-joined portions 231a and 231b of the inner fin 23.
The protruding portion 232b is formed so as to protrude in the Z2 direction from the non-joined portions 231a and 231b. The protrusion 232b is formed so as to extend in the direction in which the X2 direction component and the Y1 direction component are combined.

The protruding portion 232c is formed so as to protrude in the Z1 direction from the non-joined portions 231a and 231b. The protrusion 232c is formed so as to extend in the direction in which the X2 direction component and the Y2 direction component are combined.
As shown in FIGS. 12A and 12B, the protrusions 232b and 232c are formed so as not to come into contact with the outer wall portions 210 and 211 of the tube 21.

Next, an operation example of the heat exchanger 10 of this modification will be described.
When the protrusion 232c is formed on the inner fin 23, the flow direction of the cooling water flowing inside the tube 21 can be changed as shown by an arrow in FIG. 13, for example. Note that FIG. 13 illustrates a case where the cross-sectional shape of the protrusion 232c is trapezoidal. As shown in FIG. 13, when the cooling water reaches the protrusion 232c, the cooling water flows along the outer surface of the protrusion 232c, so that the flow direction of the cooling water flowing inside the outer wall portion 210 of the tube 21 is Z1. Can be changed in direction. As a result, the cooling water flows so as to collide with the inner wall surface of the tube 21, so that heat exchange is easily performed between the inner wall surface of the tube 21 and the cooling water. The same action and effect are exhibited at the protrusion 232c. As a result, the heat exchange between the air flowing through the outer fins 22 and the cooling water flowing inside the tube 21 can be further promoted, so that the heat transfer coefficient of the heat exchanger 10 can be improved. It is desirable that all the protrusions 232b and 232c do not come into contact with the outer wall portions 210 and 211 of the tube 21, but as long as the same or similar effect as the heat exchanger 10 of the present embodiment can be obtained, the protrusions A part of 232b and 232c may be in contact with the outer wall portions 210 and 211 of the tube 21.

Further, as shown in FIG. 11, in the tube 21 of the present modification, the protrusion 232c protruding in the Z2 direction and the protrusion 232c protruding in the Z1 direction are alternately arranged in the X2 direction, in other words, cooling water. Since the cooling water is alternately arranged in the flow direction of, the cooling water repeatedly collides with the inner wall surface of the tube 21 in the Z1 direction and the inner wall surface in the Z2 direction discontinuously and alternately. As a result, the heat transfer coefficient of the heat exchanger 10 can be improved while reducing the pressure loss of the cooling water.

(Third Modification)
Next, a third modification of the heat exchanger 10 of the second embodiment will be described.
As shown in FIGS. 14 and 15 (A) and 15 (B), in the heat exchanger 10 of this modified example, the protrusions 232b and 232c move toward the X1 direction, in other words, in the direction of the cooling water flow. It has a shape in which the amount of protrusion increases toward the upstream side, a so-called fish shadow streamline shape. The shapes of the protrusions 232b and 232c are also referred to as inclined blade shapes.

Next, an operation example of the heat exchanger 10 of this modification will be described.
When the cooling water flows as shown by an arrow in FIG. 13, the cooling water that exceeds the protrusion 232b tends to flow so as to deviate from the inner fin 23. This is a factor that reduces the heat transfer area of the cooling water in the inner fin 23.

In this respect, if the protrusions 232 are formed in a streamlined shape like the heat exchanger 10 of this modified example, the cooling water exceeding the protrusions 232b and 232c can easily flow along the inner fins 23. Therefore, it is possible to suppress a decrease in the heat transfer area of the cooling water in the inner fin 23.
(Fourth modification)
Next, a fourth modification of the heat exchanger 10 of the second embodiment will be described.

As shown in FIGS. 16 and 17 (A) and 17 (B), in the heat exchanger 10 of this modified example, the cross-sectional shapes of the protrusions 232b and 232c orthogonal to the Z1 and Z2 directions are formed in a circular shape. There is. According to such a configuration, the cooling water easily flows along the periphery of the protrusions 232b and 232c, so that the cooling water is less likely to deviate from the protrusions 232b and 232c. As a result, the heat transfer coefficient around the protrusions 232b and 232c in the inner fin 23 can be locally improved.

<Other embodiments>
In addition, each embodiment can also be implemented in the following embodiments.
In the heat exchanger 10 of each embodiment, the space partitioned by the joint portions 230a and 230b of the inner fin 23, the non-joint portions 231a, and the outer wall portions 210 and 211 of the tube 21 is set as the first space S1, and the inner fin 23 When the space partitioned by the joint portions 230b and 230c, the non-joint portions 231b, and the outer wall portions 210 and 211 of the tube 21 is the second space S2, the first space S1 and the second space S2 are tubes in the air flow direction Y. It may have a shape that is line-symmetrical with respect to the center line of 21. According to such a configuration, it is possible to flow the cooling water more uniformly in the internal flow path of the tube 21.

The inner fin 23 of the first embodiment may have a plurality of protrusions 210a and 211a formed line-symmetrically with respect to the center line in the air flow direction Y. Further, the plurality of protrusions 210a and 211a may be arranged in a staggered pattern or a grid pattern.
-The configuration of the heat exchanger 10 of the present embodiment can be applied to any heat exchanger. Applicable heat exchangers include, for example, heat exchangers in which only one type of fluid flows, small-sized down-face heat exchangers, medium-sized half-face heat exchangers, and large-sized full-face heat exchangers. There is a heat exchanger. Further, the flow direction of the cooling water in the heat exchanger 10 can be changed as appropriate. For example, as the heat exchanger 10, it is also possible to adopt a so-called downflow type in which cooling water flows in the vertical direction.

-The configuration of the heat exchanger 10 of each embodiment is not limited to the radiator that cools the cooling water, and can be applied to any heat exchanger such as a condenser that condenses the refrigerant by heat exchange between air and the refrigerant. Is. When the configuration of the heat exchanger 10 of each embodiment is applied to the condenser, the refrigerant corresponds to the first fluid and the air corresponds to the second fluid.

As shown in FIG. 18, in the heat exchanger 10, the protrusions 210a and 211a may be formed on the tube 21 and the protrusions 232a and 232a may be formed on the inner fin 23. Further, the tube 21 may have a structure in which the tip thereof does not hold the inner fin 23.

As shown in FIG. 19, in the heat exchanger 10 of the first embodiment, the protrusions 210a and 211a of the tube 21 may be in contact with the inner fins 23. Further, in the heat exchanger 10 of the second embodiment, the protrusion 232a of the inner fin 23 may be in contact with the inner surface of the tube 21.

The number of protrusions 210a, 211a formed on the tube 21 of the first embodiment and the number of joints 230a, 230b, 230c formed on the inner fin 23 can be arbitrarily changed. Further, the number of protrusions 232a, 232b, 232c formed on the inner fin 23 of the second embodiment and the number of joints 230a, 230b, 230c can be arbitrarily changed.

・ This disclosure is not limited to the above specific examples. Specific examples described above with appropriate design changes by those skilled in the art are also included in the scope of the present disclosure as long as they have the features of the present disclosure. Each element included in each of the above-mentioned specific examples, and their arrangement, conditions, shape, and the like are not limited to those illustrated, and can be changed as appropriate. The combinations of the elements included in each of the above-mentioned specific examples can be appropriately changed as long as there is no technical contradiction.

Claims (9)

1. A heat exchanger having a plurality of tubes (21) arranged in a laminated manner, in which heat exchange is performed between a first fluid flowing inside the tubes and a second fluid flowing outside the tubes. hand,
   A fin (23) housed inside the tube.
   The fins
   Joints (230a, 230b, 230c) that are bent in a wavy shape at a predetermined fin pitch and the tip of the bent portion is joined to the inner surface of the tube.
   It has a non-joint portion (231a, 231b) that is formed longer than the predetermined fin pitch and is not joined to the inner surface of the tube.
   A heat exchanger in which protrusions (210a, 211a) are formed on outer wall portions (210, 211) facing the non-joint portion in the tube.
2. The heat exchanger according to claim 1, wherein the protrusion is formed so as to protrude inside the tube.
3. The heat exchanger according to claim 1 or 2, wherein the protrusions are formed so as not to come into contact with the fins.
4. The heat exchanger according to claim 1, wherein the protrusion is formed so as to protrude to the outside of the tube.
5. A heat exchanger having a plurality of tubes (21) arranged in a laminated manner, in which heat exchange is performed between a first fluid flowing inside the tubes and a second fluid flowing outside the tubes. hand,
   A fin (23) housed inside the tube.
   The fins
   Joints (230a, 230b, 230c) that are bent in a wavy shape at a predetermined fin pitch and the tip of the bent portion is joined to the inner surface of the tube.
   It has a non-joint portion (231a, 231b) that is formed longer than the predetermined fin pitch and is not joined to the inner surface of the tube.
   A heat exchanger in which protrusions (232a, 232b, 232c) are formed in the non-joint portion.
6. The heat exchanger according to claim 5, wherein the protrusion is formed by cutting up a part of the non-joint portion.
7. The heat exchanger according to claim 5 or 6, wherein the protrusion is formed so as not to come into contact with the inner surface of the tube.
8. The heat exchanger according to any one of claims 1 to 7, wherein the non-joint portion is formed so as to extend parallel to the inner surface of the tube.
9. A heat exchanger having a plurality of tubes (21) arranged in a laminated manner, in which heat exchange is performed between a first fluid flowing inside the tubes and a second fluid flowing outside the tubes. hand,
   A fin (23) housed inside the tube.
   The fins
   Joints (230a, 230b, 230c) that are bent in a wavy shape at a predetermined fin pitch and the tip of the bent portion is joined to the inner surface of the tube.
   It has a non-joint portion (231a, 231b) that is formed longer than the predetermined fin pitch and is not joined to the inner surface of the tube.
   Protrusions (210a, 211a) are formed on the outer wall portions (210,211) facing the non-joint portion in the tube.
   A heat exchanger in which a protrusion (232a) is formed on the non-joint portion.

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