HEAT EXCHANGER

Description

TECHNICAL FIELD

The present disclosure relates to a heat exchanger.

Priority is claimed on Japanese Patent Application No. 2022-089006, filed May 31, 2022, the content of which is incorporated herein by reference.

BACKGROUND ART

In a so-called fin tube type heat exchanger including plate fins and heat transfer tubes, it is desired to improve a heat transfer coefficient of the plate fin in order to improve heat exchange efficiency. Patent Document 1 discloses a configuration in which a plate fin surrounding the heat transfer tube is cut, a guide fin inclined with respect to a gas flow direction is formed, and the guide fin guides a gas flow to a downstream region of the heat transfer tube in the gas flow direction.

Patent Document 2 discloses a configuration in which ventilation resistance is reduced by providing notch portions that expand toward an upstream side in a gas flow direction at positions which are located at an equal distance from two adjacent heat transfer tubes among end edge portions of the plate fins on the upstream side in the gas flow direction.

Patent Document 3 discloses a configuration in which a curved line or a bent line is continuously formed in a direction of stages of heat transfer tubes at a distance of approximately half of a distance between the heat transfer tubes in a column direction of the heat transfer tubes, and the plate fins are cut such that projected portions and recessed portions are engaged with each other as a whole. In Patent Document 3, the plate fins are formed in this way, and thus, a variation in the heat transfer distance from each heat transfer tube to the edge of the plate fin is reduced without changing an area of the plate fin. Therefore, efficiency of the fin can be improved.

CITATION LIST

Patent Documents

Patent Document 1: PCT International Publication No. WO2007/004457.

Patent Document 2: Japanese Patent No. 3910475.

Patent Document 3: Japanese Unexamined Patent Application, First Publication No. 2001-033183.

SUMMARY OF INVENTION

Technical Problem

In the fin tube type heat exchangers described in Patent Documents 1 to 3, an amount of heat exchange can be efficiently increased by increasing a heat transfer coefficient from the gas flow to the plate fin. That is, in the heat exchanger, the amount of heat exchange can be easily improved by increasing the heat transfer area. However, in a case where the heat transfer area is increased, there is a problem that the heat exchanger becomes large and it is difficult to reduce the weight of the heat exchanger.

The present disclosure has been made in view of the above circumstances, and provides a heat exchanger capable of reducing the weight of the heat exchanger while increasing an amount of heat exchange.

Solution to Problem

In order to solve the above problems, the following configuration is adopted.

According to a first aspect of the present disclosure, a heat exchanger is provided including: a plurality of heat transfer tubes that are disposed in a flow of a gas, extend in a second direction intersecting a first direction in which the gas flows, and are arranged at intervals; and a plurality of plate fins that extend in the first direction, are provided to straddle the plurality of heat transfer tubes, and are arranged at intervals in the second direction, in which the plate fins include a plurality of slits that extend in a third direction and are arranged at intervals in the first direction, the third direction being a direction intersecting both the first direction and the second direction, the plurality of slits have zigzag shapes alternately and obliquely extending toward an upstream side and a downstream side of the first direction in which the gas flows, and patterns of the zigzag shapes match each other.

According to a second aspect of the present disclosure, a heat exchanger is provided including: a plurality of heat transfer tubes that are disposed in a flow of a gas, extend in a second direction intersecting a first direction in which the gas flows, and are arranged in a staggered arrangement in which the plurality of heat transfer tubes are alternately shifted in a third direction, which is a direction intersecting both the first direction and the second direction; and a plurality of plate fins that extend in the first direction, are provided to straddle the plurality of heat transfer tubes, and are arranged at intervals in the second direction, in which the plate fins include holes that penetrate in the second direction on an upstream side of each of the plurality of heat transfer tubes in the first direction.

Advantageous Effects of Invention

With the heat exchanger according to the present disclosure, it is possible to reduce the weight of the heat exchanger while increasing the amount of heat exchange.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 A diagram showing a schematic configuration of a heat exchanger according to a first embodiment of the present disclosure.

FIG. 2 A cross-sectional view taken along a line II-II of FIG. 1.

FIG. 3 A cross-sectional view of the heat exchanger according to a second embodiment of the present disclosure and corresponding to FIG. 2.

FIG. 4 An enlarged view of a main part of FIG. 3.

FIG. 5 An enlarged view of the heat exchanger according to a first modification example of the second embodiment of the present disclosure and corresponding to FIG. 4.

FIG. 6 An enlarged view of the heat exchanger according to a second modification example of the second embodiment of the present disclosure and corresponding to FIG. 4.

FIG. 7 An enlarged view of the heat exchanger according to a third modification example of the second embodiment of the present disclosure and corresponding to FIG. 4.

FIG. 8 An enlarged view of the heat exchanger according to a fourth modification example of the second embodiment of the present disclosure and corresponding to FIG. 4.

FIG. 9 A cross-sectional view of the heat exchanger according to a fifth modification example of the second embodiment of the present disclosure and corresponding to FIG. 2.

FIG. 10 A cross-sectional view taken along a line X-X of FIG. 1.

FIG. 11 A cross-sectional view of the heat exchanger according to a fourth embodiment of the present disclosure and corresponding to FIG. 10.

FIG. 12 An enlarged view of a main part of FIG. 11.

FIG. 13 An enlarged view of the heat exchanger according to a first modification example of the fourth embodiment of the present disclosure and corresponding to FIG. 12.

FIG. 14 An enlarged view of the heat exchanger according to a second modification example of the fourth embodiment of the present disclosure and corresponding to FIG. 12.

FIG. 15 An enlarged view of the heat exchanger according to a third modification example of the fourth embodiment of the present disclosure and corresponding to FIG. 12.

FIG. 16 An enlarged view of the heat exchanger according to a fourth modification example of the fourth embodiment of the present disclosure and corresponding to FIG. 12.

DESCRIPTION OF EMBODIMENTS

First Embodiment

Next, a heat exchanger according to a first embodiment of the present disclosure will be described with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a heat exchanger according to a first embodiment of the present disclosure.

As shown in FIG. 1, a heat exchanger 101 according to the first embodiment exchanges heat between a gas G supplied from the outside and a refrigerant R. The heat exchanger 101 includes heat transfer tubes 102 and plate fins 103. In the following description, a flow of the gas G for heat exchange in the heat exchanger is simply referred to as a gas flow. In addition, a direction in which the gas G flows is referred to as a first direction D1, an upstream side of the gas flow is referred to as a first-direction upstream side D1u, and a downstream side of the gas flow is referred to as a first-direction downstream side D1d.

The heat transfer tubes 102 are disposed in the gas flow. The heat transfer tubes 102 extend in a second direction D2 intersecting the first direction D1. A plurality of heat transfer tubes 102 are arranged at intervals in the gas flow. A heat transfer tube group 105 is formed of the plurality of heat transfer tubes 102 arranged in this manner. The heat transfer tubes 102 in the heat transfer tube group 105 described in the present embodiment have the same shape, and the refrigerant R flows inside the heat transfer tubes 102. Although a case where the second direction D2 in the present embodiment is a direction perpendicular to the first direction D1 is shown, the second direction D2 is not limited to a direction perpendicular to the first direction D1. In the following description, a direction intersecting the first direction D1 and the second direction D2 is referred to as a third direction D3 (refer to FIG. 2).

FIG. 2 is a cross-sectional view taken along a line II-II of FIG. 1.

As shown in FIG. 2, the heat transfer tubes 102 included in the heat transfer tube group 105 are disposed in a so-called staggered arrangement. In other words, the heat transfer tubes 102 in the heat transfer tube group 105 are arranged in an orthorhombic grid. That is, the plurality of heat transfer tubes 102 in the heat transfer tube group 105 are alternately shifted and arranged in the first direction D1 and the third direction D3.

The heat transfer tubes 102 in the heat transfer tube group 105 according to the present embodiment form a first column C1 and a second column C2 extending in the first direction D1, and the first column C1 and the second column C2 are alternately arranged in the third direction D3. In addition, the heat transfer tubes 102 in the first column C1 are disposed at an interval of a distance L1 in the first direction D1. Each heat transfer tube 102 in the second column C2 is disposed at an interval of a distance L1 in the first direction D1 and is disposed by being shifted in the first direction D1 by a distance L2, which is a half of the distance L1, with respect to a position of the heat transfer tube 102 in the first column C1. In the following description, the heat transfer tubes 102 arranged in the first direction D1 may be referred to as a column (C), and the heat transfer tubes 102 arranged in the third direction D3 may be referred to as a stage (S). The heat transfer tube group 105 according to the present embodiment includes a plurality of columns and a plurality of stages of heat transfer tubes 102. In addition, for convenience of illustration, in order to show the columns C (C1, C2) and the stages S in FIG. 2, reference numerals are attached to axes passing through the centers of the heat transfer tubes 102 included in the columns C (C1, C2) and the stages S.

The plate fin 103 is provided to extend in the first direction D1 and to straddle the plurality of heat transfer tubes 102. A plurality of plate fins 103 are arranged at intervals in the second direction D2 (refer to FIG. 1). Each of the plurality of plate fins 103 according to the present embodiment is formed in a thin plate shape, and is disposed at an equal interval in the second direction D2. The above-described gas flow flows between the plate fins 103 from the first-direction upstream side D1u to the first-direction downstream side D1d.

The plate fin 103 includes a slit 104. The slit 104 extends in the third direction D3. More specifically, the slit 104 is formed to cross the plate fin 103 in the third direction D3. A plurality of slits 104 are arranged at intervals in the first direction D1. The plurality of slits 104 penetrate the plate fins 103 in the second direction D2 which is a thickness direction of the plate fins 103. The slits 104 according to the present embodiment are provided for each of the two-stage heat transfer tubes 102 in the heat transfer tube group 105 that are adjacent to each other in the first direction D1.

The plurality of slits 104 have zigzag shapes alternately and obliquely extending to the first-direction upstream side D1u and the first-direction downstream side D1d. The plurality of slits 104 have patterns of the zigzag shapes that match each other. In other words, for example, the plurality of slits 104 match each other at positions of projected portions 106, which are formed to be projected in the third direction D3 toward the first-direction upstream side D1u, and positions of recessed portions 107, which are formed to be recessed in the third direction D3 toward the first-direction downstream side D1d. In addition, the pattern of the zigzag shape of the slit 104 described in the present embodiment matches a pattern in which the heat transfer tubes 102 are disposed at equal intervals in the third direction D3. In addition, amplitude of the zigzag shape of the slit 104 is constant.

The slit 104 extends toward the first-direction upstream side D1u at a position between the heat transfer tubes 102 adjacent to each other in the third direction D3 on the stage S adjacent to the first-direction upstream side D1u. In addition, the slit 104 extends toward the first-direction downstream side D1d at a position between the heat transfer tubes 102 adjacent to each other in the third direction D3 on the stage S adjacent to the first-direction downstream side D1d. In the present embodiment, a position of a vertex t of the zigzag shape in the third direction D3 matches the position of the heat transfer tube 102 in the third direction D3.

More specifically, in the present embodiment, the position of a folded portion of the projected portion 106, which is the vertex t of the slit 104 in the third direction D3, matches that of the center of the heat transfer tube 102 in the first column C1. Similarly, the position of a folded portion of the recessed portion 107, which is the vertex t of the slit 104 in the third direction D3, matches that of the center of the heat transfer tube 102 in the second column C2. In addition, in the present embodiment, a distance in the first direction D1 between the vertex t and the heat transfer tube 102 in the first column C1 disposed at a position closest to the vertex t in the first direction D1 is the same as a distance in the first direction D1 between the vertex t and the heat transfer tube 102 in the second column C2. The position of the folded portion of the projected portion 106 or the recessed portion 107 is not limited to a case where the position matches the center position of the heat transfer tube 102. For example, the position may be slightly shifted from the center position of the heat transfer tube 102.

In the slit 104 described in the present embodiment, the portion of the slit 104 extending toward the first-direction upstream side D1u extends toward the first-direction upstream side D1u as compared to the center of the heat transfer tube 102 on the stage S adjacent to the first-direction upstream side D1u. On the other hand, in the slit 104, the portion of the slit 104 extending toward the first-direction upstream side D1u does not extend toward the first-direction upstream side D1u as compared to the heat transfer tube 102 on the stage adjacent to the first-direction upstream side D1u. That is, the slit 104 is located at the same position as a point P1 of the heat transfer tube 102 that is located to be closest to the first-direction upstream side D1u on the stage S adjacent to the first-direction upstream side D1u, or at a position that is located toward the first-direction downstream side D1d as compared to the point P1.

Similarly, in the slit 104 described in the present embodiment, the portion of the slit 104 extending toward the first-direction downstream side D1d extends toward the first-direction downstream side D1d as compared to the center of the heat transfer tube 102 on the stage S adjacent to the first-direction downstream side D1d. On the other hand, in the slit 104, the portion of the slit 104 extending toward the first-direction downstream side D1d does not extend toward the first-direction downstream side D1d as compared to the heat transfer tube 102 on the stage S adjacent to the first-direction downstream side D1d. That is, the slit 104 is located at the same position as a point P2 of the heat transfer tube 102 that is located to be closest to the first-direction downstream side D1d on the stage S adjacent to the first-direction downstream side D1d, or at a position that is located toward the first-direction upstream side D1u as compared to the point P2.

Actions and Effects

In the heat exchanger 101 according to the first embodiment, the plate fins 103 have the plurality of slits 104 that extend in the third direction D3 and are arranged at intervals in the first direction D1, the plurality of slits 104 form zigzag shapes alternately and obliquely extending toward the first-direction upstream side D1u and the first-direction downstream side D1d, and the patterns of the zigzag shapes match each other.

Therefore, in a case where the gas G flows from the first-direction upstream side D1u to the first-direction downstream side D1d, the gas flow is disturbed by the slit 104, and a temperature boundary layer of the gas flow can be thinned. Therefore, a temperature gradient from the plate fins 103 can be steepened, and an amount of heat exchange can be increased. In addition, the slit 104 is formed in a zigzag shape, and thus a length of the slit 104 can be increased as compared with a case where the slit 104 is formed in a linear shape. Thereby, the weight of the plate fin 103 can be reduced. Further, since the patterns of the zigzag shapes of the plurality of slits 104 extending in the third direction D3 match each other, a distance between the slits 104 adjacent to each other in the first direction D1 can be made uniform, and a contact area between the gas flow and the plate fins can be secured. As a result, it is possible to prevent a decrease in the amount of heat exchange while reducing development of the temperature boundary layer.

In the heat exchanger 101 according to the first embodiment, further, the heat transfer tubes 102 are disposed in a staggered arrangement, and the slit 104 extends toward the first-direction upstream side D1u between the plurality of heat transfer tubes 102 arranged in the third direction D3 to be adjacent to the slit 104 and the first-direction upstream side D1u.

Thereby, in a case where the heat transfer tubes 102 are disposed in a staggered arrangement, it is possible to reduce a distance between the heat transfer tube 102, which is disposed on the first-direction upstream side D1u by one stage as compared to the heat transfer tube 102 on the stage adjacent to the first-direction upstream side D1u, and the slit 104 on the first-direction downstream side D1d of the heat transfer tube 102. Therefore, development of the temperature boundary layer on the first-direction downstream side D1d of the heat transfer tube 102 can be prevented, and thus, it is possible to increase the amount of heat exchange.

In the heat exchanger 101 according to the first embodiment, further, the position of the vertex t of the zigzag shape in the third direction D3 matches the position of the heat transfer tube 102 in the third direction D3.

Thereby, the distance between the heat transfer tubes 102 disposed in a staggered arrangement and the slits 104 can be further made uniform.

In the heat exchanger 101 according to the first embodiment, further, the slit 104 is provided for each of two-stage heat transfer tubes 102 arranged in the third direction D3 and adjacent to each other in the first direction D1.

Thereby, it is possible to more effectively increase the amount of heat exchange.

Modification Example of First Embodiment

A width of the slit 104 in the first direction D1 in the first embodiment described above may be formed, for example, to be narrower as the flow velocity of the gas flow is higher and to be wider as the flow velocity of the gas flow is lower. In this manner, even in a case where the flow velocity of the gas flow is low, it is possible to more effectively prevent development of the temperature boundary layer.

Second Embodiment

Next, a second embodiment of the present disclosure will be described with reference to the drawings. A heat exchanger 201 according to the second embodiment is obtained by adding protrusions to the heat exchanger 101 according to the first embodiment described above. Therefore, the same parts as those in the first embodiment described above will be denoted by the same reference numerals, and description of the overlapping parts with the first embodiment will be omitted.

FIG. 3 is a cross-sectional view of the heat exchanger according to the second embodiment of the present disclosure, and corresponds to FIG. 2.

As shown in FIG. 1 and FIG. 3, the heat exchanger 201 according to the second embodiment exchanges heat between the gas G supplied from the outside and the refrigerant R, similarly to the heat exchanger 101 according to the first embodiment described above. The heat exchanger 201 includes heat transfer tubes 102, plate fins 103, and protrusions 110.

FIG. 4 is an enlarged view of a main part of FIG. 3.

As shown in FIG. 3 and FIG. 4, the protrusions 110 protrude from the plate fins 103 in the second direction D2, and extend in the first direction D1. The protrusions 110 according to the present embodiment extend to straddle the plate fins 103 adjacent to each other in the second direction D2. The protrusions 110 are provided in pairs of two on the first-direction upstream side D1u and the first-direction downstream side D1d of the heat transfer tube 102. The two protrusions 110 provided on the first-direction upstream side D1u of the heat transfer tube 102 are disposed at an interval L3 in the third direction D3. Similarly, the two protrusions 110 provided on the first-direction downstream side D1d of the heat transfer tube 102 are also disposed at an interval L3 in the third direction D3.

The interval L3 is smaller than an outer diameter R1 of the heat transfer tube 102. A case where the interval L3 according to the present embodiment is half the size of the outer diameter R1 of the heat transfer tube 102 is described.

Further, a length of the protrusion 110 in the first direction D1 may be any length as long as the protrusion 110 can protrude from the heat transfer tube 102 in the first direction. In addition, a thickness of the protrusion 110 in the third direction D3 is thinner than a thickness of a tube wall of the heat transfer tube 102. In the present embodiment, a case where the thickness of the protrusion 110 is approximately half the thickness of the tube wall of the heat transfer tube 102 is described, but the present invention is not limited thereto.

In the present embodiment, a case where a pair of the protrusions 110 are disposed at the same interval L3 has been described. On the other hand, the interval between the pair of the protrusions 110 may be different in the first-direction upstream side D1u and the first-direction downstream side D1d. In addition, a case where the protrusion 110 according to the second embodiment is formed in a flat plate shape extending in the first direction D1 when viewed in the second direction D2 has been described. On the other hand, the protrusion 110 is not limited to the flat plate shape, and may have, for example, a shape that is slightly curved.

Actions and Effects

In the second embodiment, the heat exchanger 201 includes a pair of protrusions 110 on the first-direction upstream side D1u and the first-direction downstream side D1d of the heat transfer tube 102.

Thereby, the gas flows in the first direction D1 outside the pair of protrusions 110 in the third direction D3, and thus, flow passage areas on the first-direction upstream side D1u and the first-direction upstream side D1u of the heat transfer tube 102 can be reduced. Therefore, it is possible to increase the flow velocity of the gas. Therefore, in addition to prevention of development of the temperature boundary layer by the slit 104, development of the temperature boundary layer on the plate fin 103 can be further prevented.

Further, the heat transfer area of the heat transfer tube 102 can be increased by the protrusions 110, and thus, the amount of heat exchange can be further increased.

First Modification Example of Second Embodiment

FIG. 5 is an enlarged view of the heat exchanger according to a first modification example of the second embodiment of the present disclosure, and corresponds to FIG. 4.

A case where the protrusion 110 according to the second embodiment described above is formed integrally with the heat transfer tube 102 has been described. On the other hand, the protrusion 110 is not limited to the configuration in which the protrusion 110 is formed integrally with the heat transfer tube 102. For example, as in the protrusion 110 shown in FIG. 5, the protrusion 110 may be formed by performing cutting from the plate fin 103.

Second Modification Example of Second Embodiment

FIG. 6 is an enlarged view of the heat exchanger according to a second modification example of the second embodiment of the present disclosure, and corresponds to FIG. 4.

Since the protrusion 110 according to the second embodiment described above is formed integrally with the heat transfer tube 102, it is necessary to allow the heat transfer tube 102 to penetrate the plate fin 103 and then attach the protrusion 110 to the plate fin 103 by welding, adhesion, or the like.

On the other hand, as in the second modification example of the second embodiment shown in FIG. 6, by forming a protrusion through-hole 111 for allowing the protrusion 110 to penetrate the plate fin 103 in the second direction D2, even after the protrusion 110 is attached to the heat transfer tube 102, the heat transfer tube 102 can penetrate the plate fin 103. Thereby, the heat exchanger 201 including the protrusions 110 can be easily assembled.

Third Modification Example of Second Embodiment

FIG. 7 is an enlarged view of the heat exchanger according to a third modification example of the second embodiment of the present disclosure, and corresponds to FIG. 4.

A case where the protrusion 110 according to the second embodiment described above is formed integrally with the heat transfer tube 102 has been described. On the other hand, the present invention is not limited to this configuration.

For example, as in the third modification example of the second embodiment shown in FIG. 7, a gap G1 through which the gas can flow may be provided between the protrusion 110 and the heat transfer tube 102. A length of the gap G1 in the first direction D1 may be approximately the thickness of the tube wall of the heat transfer tube 102 described above. The protrusion 110 according to the third modification example of the second embodiment may be formed by performing cutting from the plate fin 103 as in the protrusion 110 according to the first modification example of the second embodiment, or for example, as in the second modification example of the second embodiment, by providing a protrusion through-hole for allowing the protrusion 110 to penetrate the plate fin 103, the protrusion 110 may be inserted into the protrusion through-hole, and then the protrusion 110 may be fixed to the plate fin 103 by welding, adhesion, or the like.

By configuring the heat exchanger 201 as in the third modification example of the second embodiment, for example, even in a case where burring is applied to the plate fin 103 around the heat transfer tube 102, the protrusions 110 can be easily provided. In addition, since the gas G flows through the gap G1 between the protrusion 110 and the heat transfer tube 102, a region where the gas G is stagnated between the pair of the protrusions 110 is reduced, and as a result, it is possible to promote the heat transfer effect.

Fourth Modification Example of Second Embodiment

FIG. 8 is an enlarged view of the heat exchanger according to a fourth modification example of the second embodiment of the present disclosure, and corresponds to FIG. 4.

In the second embodiment described above, a case where the protrusions 110 are provided on the first-direction upstream side D1u and the first-direction downstream side D1d of the heat transfer tube 102 has been described. On the other hand, for example, in the heat transfer tube group 105, as in the fourth modification example of the second embodiment shown in FIG. 8, protruding portions 112 that protrude in a direction away from the heat transfer tube 102 in the third direction D3 may be provided for part of the heat transfer tubes 102 on the first-direction downstream side D1d. By providing the protruding portions 112 in this way, the heat transfer area of the heat transfer tube 102 can be increased. Thus, it is possible to secure the amount of heat transfer in part of the heat transfer tubes 102 on the first-direction downstream side D1d in which the temperature difference between the gas G and the refrigerant R is particularly small during heat exchange. The shape of the protruding portion 112 may be any shape as long as the heat transfer area can be increased and is not limited to that shown in FIG. 8.

Fifth Modification Example of Second Embodiment

FIG. 9 is a cross-sectional view of the heat exchanger according to a fifth modification example of the second embodiment of the present disclosure, and corresponds to FIG. 2.

In the above-described second embodiment, a case where the heat transfer tubes 102 are disposed in a staggered arrangement when viewed in the second direction D2 has been described. On the other hand, the heat transfer tubes 102 are not limited to being disposed in a staggered arrangement. For example, as in the fifth modification example of the second embodiment shown in FIG. 9, the heat transfer tubes 102 may be arranged in an array of a so-called square grid or rectangular grid when viewed in the second direction D2.

Further, in a case of the staggered arrangement, a case where the interval of the slits 104 in the first direction D1 is set to every two stages of the stages S of the heat transfer tubes 102 arranged in the third direction D3 has been described. On the other hand, as shown in FIG. 9, in a case where the heat transfer tubes 102 are arranged in a grid arrangement of a square grid or a rectangular grid, the interval of the slits 104 having the zigzag shapes in the first direction D1 may be set to each stage of the stages S of the heat transfer tubes 102.

By disposing the slits 104 in this way, in a case of the grid arrangement of a square grid or a rectangular grid as described above, it is possible to efficiently perform heat exchange by averaging the heat transfer coefficient in the first direction D1, which is the gas flow direction in the heat exchanger 201.

Another Modification Example of Second Embodiment

The width of the slit 104 in the first direction D1 in the second embodiment and the modification examples described above may be formed, for example, to be narrower as the flow velocity of the gas flow is higher and to be wider as the flow velocity of the gas flow is lower, as in the first embodiment. In addition, a length of the protrusion 110 in the first direction D1 may be formed to be shorter as the flow velocity of the gas flow is higher and to be longer as the flow velocity of the gas flow is lower. In this manner, even in a case where the flow velocity of the gas flow is low, it is possible to more effectively prevent development of the temperature boundary layer.

Third Embodiment

Next, a heat exchanger according to a third embodiment of the present disclosure will be described with reference to the drawings.

A heat exchanger 301 according to the third embodiment is different from the heat exchanger 101 according to the first embodiment described above in the shape of the plate fin. Therefore, the same parts as those in the first embodiment described above will be denoted by the same reference numerals as those in the first embodiment with reference to FIG. 1.

As shown in FIG. 1, a heat exchanger 301 according to the third embodiment exchanges heat between a gas G supplied from the outside and a refrigerant R. The heat exchanger 301 includes heat transfer tubes 102 and a plate fin 303. The flow of the gas G for heat exchange in the heat exchanger 301 is simply referred to as a gas flow. In addition, a direction in which the gas G flows is referred to as a first direction D1, an upstream side of the gas flow is referred to as a first-direction upstream side D1u, and a downstream side of the gas flow is referred to as a first-direction downstream side D1d.

The heat transfer tubes 102 are disposed in the gas flow. The heat transfer tubes 102 extend in a second direction D2 intersecting the first direction D1. A plurality of heat transfer tubes 102 are arranged at intervals in the gas flow. A heat transfer tube group 105 is formed of the plurality of heat transfer tubes 102 arranged in this manner. The heat transfer tubes 102 in the heat transfer tube group 105 described in the present embodiment have the same shape, and the refrigerant R flows inside the heat transfer tubes 102. Although a case where the second direction D2 in the present embodiment is a direction perpendicular to the first direction D1 is shown, the second direction D2 is not limited to a direction perpendicular to the first direction D1. In the following description, a direction intersecting the first direction D1 and the second direction D2 is referred to as a third direction D3.

FIG. 10 is a cross-sectional view taken along a line X-X in FIG. 1.

As shown in FIG. 10, the heat transfer tubes 102 included in the heat transfer tube group 105 are disposed in a so-called staggered arrangement. In other words, the heat transfer tubes 102 in the heat transfer tube group 105 are arranged in an orthorhombic grid with respect to the first direction D1. That is, the plurality of heat transfer tubes 102 in the heat transfer tube group 105 are alternately shifted and arranged in the first direction D1 and the third direction D3.

The heat transfer tubes 102 in the heat transfer tube group 105 according to the present embodiment form a first column C1 and a second column C2 extending in the first direction D1, and the first column C1 and the second column C2 are alternately arranged in the third direction D3. In addition, the heat transfer tubes 102 in the first column C1 are disposed at an interval of a distance L1 in the first direction D1. Each heat transfer tube 102 in the second column C2 is disposed at an interval of a distance L1 in the first direction D1 and is disposed by being shifted in the first direction D1 by a distance L2, which is a half of the distance L1, with respect to a position of the heat transfer tube 102 in the first column C1. In the following description, the heat transfer tubes 102 arranged in the first direction D1 may be referred to as a column (C), and the heat transfer tubes 102 arranged in the third direction D3 may be referred to as a stage (S). The heat transfer tube group 105 according to the present embodiment includes a plurality of columns and a plurality of stages of heat transfer tubes 102. In the third embodiment, only two columns of the heat transfer tubes 102 are shown. On the other hand, three or more columns of the heat transfer tubes 102 may be provided.

The plate fin 303 is provided to extend in the first direction D1 and to straddle the plurality of heat transfer tubes 102. A plurality of plate fins 103 are arranged at intervals in the second direction D2. Each of the plurality of plate fins 103 according to the present embodiment is formed in a thin plate shape, and is disposed at an equal interval in the second direction D2. The above-described gas flow flows between the plate fins 103 from the first-direction upstream side D1u to the first-direction downstream side D1d.

The plate fin 103 has holes 304 penetrating in the second direction D2. The holes 304 are formed on the first-direction upstream side D1u of each of the plurality of heat transfer tubes 102. The hole 304 according to the third embodiment has a rectangular shape in which the first direction D1 is a longitudinal direction when viewed in the second direction D2. Further, in the hole 304 according to the third embodiment, the center of the heat transfer tube 102 adjacent to the first-direction downstream side D1d is located on an extension line of an axis passing through the center of the rectangular shape in the third direction D3 when viewed in the second direction D2. In addition, a case where the center position of the hole 304 according to the third embodiment is the same position in the first direction D1 as the center position of the heat transfer tube 102 in the column C adjacent to the column C in the third direction D3 in which the hole 304 is formed is shown. On the other hand, the center positions may be shifted in the first direction D1.

The hole 304 is formed in a region of the plate fin 303 that is determined as a region having a small contribution to heat transfer by optimization analysis or the like performed in advance. In the third embodiment, a short side of the hole 304 having a rectangular shape is formed to be smaller than an outer diameter R1 of the heat transfer tube 102. In addition, in the third embodiment, a case where the short side of the hole 304 having a rectangular shape is slightly shorter than half the length of the outer diameter of the heat transfer tube 102 and the long side of the hole 304 is formed to be slightly smaller than an inner diameter R2 of the heat transfer tube 102 is shown. The shape of the hole 304 is not limited to the above shape or size as long as the shape includes a region of the plate fin 303 that is determined as a region having a small contribution to heat transfer by optimization analysis or the like. In a case where the shape of the hole 304 is the above-described rectangular shape, there is an advantage in that processing can be easily performed.

Actions and Effects

In the heat exchanger 301 according to the third embodiment, the plurality of heat transfer tubes 102 are disposed in the gas flow, extend in the second direction D2, and are alternately shifted in the first direction D1 and the third direction D3 in a staggered arrangement. The plate fin 303 is provided to extend in the first direction D1 and to straddle the plurality of heat transfer tubes 102, and a plurality of plate fins 303 are arranged at intervals in the second direction D2. In addition, the plate fin 303 has holes 304 that penetrate in the second direction D2 on the first-direction upstream side D1u of each of the plurality of heat transfer tubes 102.

Thereby, in a case where the gas G flows from the first-direction upstream side D1u to the first-direction downstream side D1d, the gas flow is disturbed by the holes 304, and a temperature boundary layer of the gas flow can be thinned. Therefore, a temperature gradient from the plate fins 303 can be steepened, and an amount of heat exchange can be increased. In addition, the holes 304 penetrate the plate fin 303, and thus, the plate fin 303 can be made lighter by an opening area of the holes 304 as compared to a case where the holes 304 are not provided.

As a result, it is possible to prevent a decrease in the amount of heat exchange while reducing development of the temperature boundary layer.

Further, it is sufficient to form the holes 304 penetrating the plate fin 303 in the second direction D2. Thus, the plate fin 303 can be easily manufactured, and it is possible to prevent the processing steps from being complicated.

Fourth Embodiment

Next, a fourth embodiment of the present disclosure will be described with reference to the drawings. A heat exchanger 401 according to the fourth embodiment is obtained by adding protrusions to the heat exchanger 301 according to the third embodiment described above. Therefore, with reference to FIG. 1, the same parts as those in the third embodiment described above will be denoted by the same reference numerals, and description of the overlapping parts with the third embodiment will be omitted.

FIG. 11 is a cross-sectional view of the heat exchanger according to the fourth embodiment of the present disclosure, and corresponds to FIG. 10. As shown in FIG. 1 and FIG. 11, the heat exchanger 401 according to the fourth embodiment exchanges heat between the gas G supplied from the outside and the refrigerant R, similarly to the heat exchanger 101 according to the first embodiment described above. The heat exchanger 401 includes heat transfer tubes 102, plate fins 303, and protrusions 110.

FIG. 12 is an enlarged view of a main part of FIG. 11.

As shown in FIG. 11 and FIG. 12, the protrusions 110 protrude from the plate fins 303 in the second direction D2, and extend in the first direction D1. The protrusions 110 according to the fourth embodiment extend to straddle the plate fins 303 adjacent to each other in the second direction D2. The protrusions 110 are provided in pairs of two on the first-direction upstream side D1u and the first-direction downstream side D1d of the heat transfer tube 102. The two protrusions 110 provided on the first-direction upstream side D1u of the heat transfer tube 102 are disposed at an interval L3 in the third direction D3. Similarly, the two protrusions 110 provided on the first-direction downstream side D1d of the heat transfer tube 102 are also disposed at an interval L3 in the third direction D3.

The interval L3 is smaller than an outer diameter of the heat transfer tube 102. A case where the interval L3 according to the present embodiment is half the size of the outer diameter of the heat transfer tube 102 is described. Further, a length of the protrusion 110 in the first direction D1 may be any length as long as the protrusion 110 can protrude from the heat transfer tube 102 in the first direction. In addition, a thickness of the protrusion 110 in the third direction D3 is thinner than a thickness of a tube wall of the heat transfer tube 102.

In the present embodiment, a case where the thickness of the protrusion 110 is approximately half the thickness of the tube wall of the heat transfer tube 102 is described, but the present invention is not limited thereto.

In the fourth embodiment, a case where a pair of the protrusions 110 are disposed at the same interval L3 has been described. On the other hand, the interval between the pair of the protrusions 110 may be different in the first-direction upstream side D1u and the first-direction downstream side D1d. In addition, a case where the protrusion 110 according to the fourth embodiment is formed in a flat plate shape extending in the first direction D1 when viewed in the second direction D2 has been described. On the other hand, the protrusion 110 is not limited to the flat plate shape, and may have, for example, a shape that is slightly curved.

Actions and Effects

In the fourth embodiment, the heat exchanger 401 includes a pair of protrusions 110 on the first-direction upstream side D1u and the first-direction downstream side D1d of the heat transfer tube 102.

Thereby, the gas flows in the first direction D1 outside the pair of protrusions 110 in the third direction D3, and thus, flow passage areas on the first-direction upstream side D1u and the first-direction upstream side D1u of the heat transfer tube 102 can be reduced. Therefore, it is possible to increase the flow velocity of the gas. Therefore, in addition to prevention of development of the temperature boundary layer by the holes 304, development of the temperature boundary layer on the plate fin 103 can be further prevented.

Further, the heat transfer area of the heat transfer tube 102 can be increased by the protrusions 110, and thus, the amount of heat exchange can be further increased.

First Modification Example of Fourth Embodiment

FIG. 13 is an enlarged view of the heat exchanger according to a first modification example of the fourth embodiment of the present disclosure, and corresponds to FIG. 12.

A case where the protrusion 110 according to the fourth embodiment described above is formed integrally with the heat transfer tube 102 has been described. On the other hand, the protrusion 110 is not limited to the configuration in which the protrusion 110 is formed integrally with the heat transfer tube 102. For example, as in the protrusion 110 shown in FIG. 13, the protrusion 110 may be formed by performing cutting from the plate fin 303.

Second Modification Example of Fourth Embodiment

FIG. 14 is an enlarged view of the heat exchanger according to a second modification example of the fourth embodiment of the present disclosure, and corresponds to FIG. 12.

Since the protrusion 110 according to the fourth embodiment described above is formed integrally with the heat transfer tube 102, it is necessary to allow the heat transfer tube 102 to penetrate the plate fin 303 and then attach the protrusion 110 to the plate fin 303 by welding, adhesion, or the like.

On the other hand, as in the second modification example of the fourth embodiment shown in FIG. 14, by forming a protrusion through-hole 111 for allowing the protrusion 110 to penetrate the plate fin 303 in the second direction D2, even after the protrusion 110 is attached to the heat transfer tube 102, the heat transfer tube 102 can penetrate the plate fin 303. Thereby, the heat exchanger 401 including the protrusions 110 can be easily assembled.

Third Modification Example of Fourth Embodiment

FIG. 15 is an enlarged view of the heat exchanger according to a third modification example of the fourth embodiment of the present disclosure, and corresponds to FIG. 12.

A case where the protrusion 110 according to the fourth embodiment described above is formed integrally with the heat transfer tube 102 has been described. On the other hand, the present invention is not limited to this configuration.

For example, as in the third modification example of the fourth embodiment shown in FIG. 15, a gap G1 through which the gas can flow may be provided between the protrusion 110 and the heat transfer tube 102. The length of the gap G1 in the first direction D1 may be approximately the thickness of the tube wall of the heat transfer tube 102 described above. The protrusion 110 according to the third modification example of the fourth embodiment may be formed by performing cutting from the plate fin 303 as in the protrusion 110 according to the first modification example of the fourth embodiment, or for example, as in the second modification example of the fourth embodiment, by providing a protrusion through-hole for allowing the protrusion 110 to penetrate the plate fin 303, the protrusion 110 may be inserted into the protrusion through-hole, and then the protrusion 110 may be fixed to the plate fin 303 by welding, adhesion, or the like.

By configuring the heat exchanger 401 as in the third modification example of the fourth embodiment, for example, even in a case where burring is applied to the plate fin 303 around the heat transfer tube 102, the protrusions 110 can be easily provided. In addition, since the gas flows through the gap G1 between the protrusion 110 and the heat transfer tube 102, a region where the gas is stagnated between the pair of the protrusions 110 is reduced, and as a result, it is possible to promote the heat transfer effect.

Fourth Modification Example of Fourth Embodiment

FIG. 16 is an enlarged view of the heat exchanger according to a fourth modification example of the fourth embodiment of the present disclosure, and corresponds to FIG. 12.

In the fourth embodiment described above, a case where the protrusions 110 are provided on the first-direction upstream side D1u and the first-direction downstream side D1d of the heat transfer tube 102 has been described. On the other hand, for example, in the heat transfer tube group 105, as in the fourth modification example of the fourth embodiment shown in FIG. 16, protruding portions 112 that protrude in a direction away from the heat transfer tube 102 in the third direction D3 may be provided for part of the heat transfer tubes 102 on the first-direction downstream side D1d. By providing the protruding portions 112 in this way, the heat transfer area of the heat transfer tube 102 can be increased. Thus, it is possible to secure the amount of heat transfer in part of the heat transfer tubes 102 on the first-direction downstream side D1d in which the temperature difference between the gas G and the refrigerant R is particularly small during heat exchange. The shape of the protruding portion 112 may be any shape as long as the heat transfer area can be increased, and is not limited to the shape shown in FIG. 16.

Another Modification Example of Fourth Embodiment

In the fourth embodiment and the modification examples described above, a length of the protrusion 110 in the first direction D1 may be formed to be shorter as the flow velocity of the gas flow is higher and to be longer as the flow velocity of the gas flow is lower. In this manner, even in a case where the flow velocity of the gas flow is low, it is possible to more effectively prevent development of the temperature boundary layer.

Other Embodiments

The present disclosure is not limited to the configurations of the above-described embodiments and modification examples, and design changes can be made without departing from the gist of the present disclosure.

For example, although a case where the slits 104 according to the first and second embodiments are formed in a form of a triangular wave is shown, an edge portion of the slit 104 is not limited to being formed in a linear shape when viewed in the second direction D2. For example, a shape in which a straight line and a curved line are combined may be used. In addition, the number of columns and the number of stages of the heat transfer tubes 102 included in the heat transfer tube group 105 may be greater than 1, and are not limited to the number of columns and the number of stages in the above-described embodiments and modification examples.

Appendix

The heat exchangers 101, 201, 301, and 401 described in the above-described embodiments are understood, for example, as follows.

(1) According to a first aspect, there is provided a heat exchanger including: a plurality of heat transfer tubes 102 that are disposed in a flow of a gas, extend in a second direction D2 intersecting a first direction D1 in which the gas flows, and are arranged at intervals; and a plurality of plate fins 103 that extend in the first direction D1, are provided to straddle the plurality of heat transfer tubes 102, and are arranged at intervals in the second direction D2, in which the plate fins 103 include a plurality of slits 104 that extend in a third direction D3 and are arranged at intervals in the first direction D1, the third direction D3 being a direction intersecting both the first direction D1 and the second direction D2, and the plurality of slits 104 have zigzag shapes that alternately and obliquely extend toward an upstream side D1u and a downstream side D1d of the first direction D1 in which the gas flows, and patterns of the zigzag shapes match each other.

Thereby, the gas flow is disturbed by the slits 104, and a temperature boundary layer of the gas flow can be thinned. Therefore, a temperature gradient from the plate fins 103 can be steepened, and an amount of heat exchange can be increased. Further, the slits 104 are formed in a zigzag shape, and thus, the length of the slit 104 can be increased. Therefore, the weight of the plate fin 103 can be reduced.

(2) According to a second aspect, in the heat exchanger according to (1), in which the heat transfer tubes 102 are arranged in a staggered arrangement in which the heat transfer tubes 102 are alternately shifted in the first direction D1 and the third direction D3, and the slits 104 extend toward the upstream side D1u in the first direction D1 between the plurality of heat transfer tubes arranged in the third direction D3 to be adjacent to each other on the upstream side D1u in the first direction D1.

Thereby, in a case where the heat transfer tubes 102 are arranged in a staggered arrangement, it is possible to reduce a distance between the heat transfer tube 102, which is disposed on the first-direction upstream side D1u by one stage as compared to the heat transfer tube 102 on the stage adjacent to the first-direction upstream side D1u, and the slit 104 on the first-direction downstream side D1d of the heat transfer tube 102.

(3) According to a third aspect, in the heat exchanger according to (2), in which a position of a vertex t of the zigzag shape in the third direction D3 matches a position of the heat transfer tube 102 in the third direction D3.

Thereby, the distance between the heat transfer tubes 102 disposed in a staggered arrangement and the slits 104 can be further made uniform.

(4) According to a fourth aspect, in the heat exchanger according to (2) or (3), in which the slits 104 are provided for every two stages of the heat transfer tubes 102 that are arranged in the third direction D3 and are adjacent to each other in the first direction D1.

Thereby, it is possible to more effectively increase the amount of heat exchange.

(5) According to a fifth aspect, the heat exchanger according to any one of (1) to (4) further includes: protrusions 110 that protrude from the plate fins 103 in the second direction D2, extend in the first direction D1, and are provided at intervals in the third direction D3 to form a pair. In the heat exchanger, the pair of the protrusions 110 are located on each of an upstream side D1u and a downstream side D1d of the heat transfer tube 102 in the first direction D1.

Thereby, the gas G flows in the first direction DI outside the pair of protrusions 110 in the third direction D3, and thus, flow passage areas on the first-direction upstream side D1u and the first-direction downstream side D1d of the heat transfer tube 102 can be reduced. Therefore, it is possible to increase the flow velocity of the gas G.

Therefore, it is possible to prevent development of a temperature boundary layer on the plate fin 103.

(6) According to a sixth aspect, in the heat exchanger according to (5), a gap G1 for allowing the gas G to flow between the protrusion 110 and the heat transfer tube 102 is provided.

Thereby, the protrusions 110 can be easily provided. In addition, since the gas G flows through the gap G1 between the protrusion 110 and the heat transfer tube 102, a region where the gas G is stagnated between the pair of the protrusions 110 is reduced, and as a result, it is possible to promote the heat transfer effect.

(7) According to a seventh aspect, the heat exchanger according to (5) or (6) further includes: protruding portions 112 that protrude toward the third direction D3 from part of the heat transfer tube 102 on the downstream side D1d in the first direction D1 among the plurality of heat transfer tubes 102.

Thereby, the heat transfer area of the heat transfer tube 102 can be increased. Thus, it is possible to secure the amount of heat transfer in part of the heat transfer tubes 102 on the first-direction downstream side D1d in which the temperature difference between the gas G and the refrigerant R is particularly small during heat exchange.

(8) According to an eighth aspect, there is provided a heat exchanger including: a plurality of heat transfer tubes 102 that are disposed in a flow of a gas G, extend in a second direction D2 intersecting a first direction D1 in which the gas G flows, and are arranged in a staggered arrangement in which the plurality of heat transfer tubes 102 are alternately shifted in a third direction D3, which is a direction intersecting both the first direction D1 and the second direction D2; and a plurality of plate fins 303 that extend in the first direction D1, are provided to straddle the plurality of heat transfer tubes 102, and are arranged at intervals in the second direction D2, in which the plate fins 303 include holes 304 that penetrate in the second direction D2 on an upstream side D1u of each of the plurality of heat transfer tubes 102 in the first direction D1. Thereby, in a case where the gas G flows from the first-direction upstream side D1u to the first-direction downstream side D1d, the gas flow is disturbed by the holes 304, and a temperature boundary layer of the gas flow can be thinned. Therefore, a temperature gradient from the plate fins 303 can be steepened, and an amount of heat exchange can be increased. In addition, the holes 304 penetrate the plate fin 303, and thus, the plate fin 303 can be made lighter by an opening area of the holes 304 as compared to a case where the holes 304 are not provided.

(9) According to a ninth aspect, the heat exchanger according to (8) further includes: protrusions 110 that protrude from the plate fins 103 in the second direction D2, extend in the first direction D1, and are provided at intervals in the third direction D3 to form a pair. In the heat exchanger, the pair of the protrusions 110 are located on each of the upstream side D1u and a downstream side D1d of the heat transfer tube 102 in the first direction D1.

Thereby, the gas G flows in the first direction D1 outside the pair of protrusions 110 in the third direction D3, and thus, flow passage areas on the first-direction upstream side D1u and the first-direction downstream side D1d of the heat transfer tube 102 can be reduced. Therefore, it is possible to increase the flow velocity of the gas. Therefore, it is possible to prevent development of a temperature boundary layer on the plate fin 103.

(10) According to a tenth aspect, in the heat exchanger according to (9), a gap G1 for allowing the gas G to flow between the protrusion 110 and the heat transfer tube 102 is provided.

Thereby, the protrusions 110 can be easily provided. In addition, since the gas G flows through the gap G1 between the protrusion 110 and the heat transfer tube 102, a region where the gas G is stagnated between the pair of the protrusions 110 is reduced, and as a result, it is possible to promote the heat transfer effect.

(11) According to an eleventh aspect, the heat exchanger according to (9) or (10) further includes: protruding portions 112 that protrude toward the third direction D3 from part of the heat transfer tube 102 on the downstream side D1d in the first direction D1 among the plurality of heat transfer tubes 102.

Thereby, the heat transfer area of the heat transfer tube 102 can be increased. Thus, it is possible to secure the amount of heat transfer in part of the heat transfer tubes 102 on the first-direction downstream side D1d in which the temperature difference between the gas G and the refrigerant R is particularly small during heat exchange.

Industrial Applicability

With the heat exchanger according to the above aspects, it is possible to reduce the weight of the heat exchanger while increasing the amount of heat exchange.

Reference Signs List

• • 101, 201, 301, 401 Heat exchanger
  • 102 Heat transfer tube
  • 103, 303 Plate fin
  • 104 Slit
  • 105 Heat transfer tube group
  • 106 Projected portion
  • 107 Recessed portion
  • 110 Protrusion
  • 111 Protrusion through-hole
  • 112 Protruding portion
  • 304 Hole
  • G Gas
  • G1 Gap
  • R Refrigerant
  • t Vertex