Heat exchanger

Abstract

This heat exchanger is provided with: a plurality of heat transfer tubes which are arranged in the flow of a gas, extend in a second direction intersecting a first direction in which the gas flows, and are arranged at intervals from each other; and a plurality of plate fins provided so as to extend in the first direction and straddle the plurality of heat transfer tubes, the plurality of plate fins being arranged so as to be spaced apart from each other in the second direction, the plate fins being provided with slits extending in a third direction, which is a direction intersecting both the first direction and the second direction. The plurality of slits are arranged at intervals in the first direction, the plurality of slits are in a zigzag shape extending alternately and obliquely toward the upstream side and the downstream side in the first direction in which the gas flows, and the periods of the zigzag shapes coincide with each other.

Description

Technical Field

[0001] The present invention relates to heat exchangers.

[0002] This application claims priority to Japanese Patent Application No. 2022-089006 filed in Japan on May 31, 2022, and the contents are incorporated herein by reference. Background Art

[0003] In a so-called fin-tube type heat exchanger having plate fins and heat transfer tubes, it is desirable to improve the heat transfer efficiency by increasing the thermal conductivity of the plate fins. Patent document 1 discloses a structure in which the plate fins around the heat transfer tubes are cut to form guide fins inclined relative to the air flow direction, and the air flow is guided to the downstream area of ​​the heat transfer tube in the air flow direction by the guide fins.

[0004] Patent Document 2 discloses a structure in which notches expanding toward the upstream side in the airflow direction are provided at positions equidistant from two adjacent heat transfer tubes at the upstream edge of a plate fin in the airflow direction, thereby reducing airflow resistance.

[0005] Patent Document 3 discloses a structure in which a curve or a bend line is continuous in the segment direction of the heat transfer tubes at a distance of approximately half the distance between the heat transfer tubes in the row direction of the heat transfer tubes, and the plate fin is cut as a whole in a manner that the concave and convex parts mesh with each other. In Patent Document 3, by forming the plate fin in this way, the deviation of the heat conduction distance from each heat transfer tube to the edge of the plate fin is reduced without changing the area of ​​the plate fin, thereby achieving an improvement in the fin efficiency.

[0006] Prior art literature

[0007] Patent Document 1: International Publication No. 2007 / 004457

[0008] Patent Document 2: Japanese Patent No. 3910475

[0009] Patent Document 3: Japanese Patent Application Publication No. 2001-033183 Summary of the invention

[0010] Problems to be solved by the invention

[0011] In the fin-tube heat exchangers described in Patent Documents 1 to 3, the heat exchange amount can be efficiently increased by improving the heat transfer rate from the airflow to the plate fins. That is, in the above-mentioned heat exchangers, the heat exchange amount can be easily increased by expanding the heat transfer area. However, when the heat transfer area is expanded, there is a problem that the heat exchanger becomes larger and it becomes difficult to reduce the weight of the heat exchanger.

[0012] The present disclosure has been made in view of the above circumstances, and provides a heat exchanger that can increase the heat exchange amount and reduce the weight.

[0013] Means for solving problems

[0014] In order to solve the above-mentioned problems, the following structure is adopted.

[0015] According to a first embodiment of the present invention, a heat exchanger comprises: a heat transfer tube, which is arranged in a gas flow, extends in a second direction intersecting the first direction of the gas flow, and is arranged in plurality at intervals from each other; and a plate fin, which is arranged in a manner extending in the first direction and spanning across the plurality of the heat transfer tubes, and is arranged in plurality at intervals from each other in the second direction, the plate fin comprising slits, the slits extending in a third direction intersecting both the first direction and the second direction, and are arranged in plurality at intervals in the first direction, the plurality of slits being in a serrated shape that extends alternately and obliquely toward the upstream side and the downstream side in the first direction of the gas flow, and the periods of the serrated shapes are consistent with each other.

[0016] According to a second embodiment of the present invention, a heat exchanger comprises: a plurality of heat transfer tubes arranged in a gas flow, extending in a second direction intersecting with a first direction of the gas flow, and arranged in a staggered arrangement alternately staggered in the first direction and in a third direction intersecting with both the first direction and the second direction; and plate fins, arranged in a manner extending in the first direction and spanning over the plurality of heat transfer tubes, and a plurality of the plate fins being arranged at intervals in the second direction, the plate fins having holes penetrating in the second direction on the upstream side of the plurality of heat transfer tubes in the first direction.

[0017] Effects of the Invention

[0018] According to the heat exchanger of the present invention, it is possible to increase the heat exchange amount and reduce the weight. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a diagram showing a schematic structure of a heat exchanger in the first embodiment of the present disclosure.

[0020] Figure 2 It is along Figure 1 Cross-sectional view along line II-II.

[0021] Figure 3 The heat exchanger in the second embodiment of the present disclosure is equivalent to Figure 2 sectional view of .

[0022] Figure 4 Yes Figure 3An enlarged view of the main part of the image.

[0023] Figure 5 The heat exchanger in the first modified example of the second embodiment of the present disclosure is equivalent to Figure 4 Magnified image of .

[0024] Figure 6 The heat exchanger in the second modification of the second embodiment of the present disclosure is equivalent to Figure 4 Magnified image of .

[0025] Figure 7 The heat exchanger in the third modified example of the second embodiment of the present disclosure is equivalent to Figure 4 Magnified image of .

[0026] Figure 8 The heat exchanger in the fourth modified example of the second embodiment of the present disclosure is equivalent to Figure 4 Magnified image of .

[0027] Fig. 9 The heat exchanger in the fifth modified example of the second embodiment of the present disclosure is equivalent to Figure 2 sectional view of .

[0028] Fig.10 It is along Figure 1 Cross-sectional view of line XX.

[0029] Fig.11 The heat exchanger in the fourth embodiment of the present disclosure is equivalent to Fig.10 sectional view of .

[0030] Fig.12 Yes Fig.11 An enlarged view of the main part of the image.

[0031] Fig.13 The heat exchanger in the first modified example of the fourth embodiment of the present disclosure is equivalent to Fig.12 Magnified image of .

[0032] Fig.14 The heat exchanger in the second modified example of the fourth embodiment of the present disclosure is equivalent to Fig.12 Magnified image of .

[0033] Fig.15 The heat exchanger in the third modified example of the fourth embodiment of the present disclosure is equivalent to Fig.12 Magnified image of .

[0034] Fig.16 The heat exchanger in the fourth modification of the fourth embodiment of the present disclosure is equivalent to Fig.12 Magnified image of . DETAILED DESCRIPTION

[0035] <<First Implementation Method>>

[0036] Next, a heat exchanger according to a first embodiment of the present disclosure will be described based on the drawings.

[0037] Figure 1 It is a diagram showing a schematic structure of a heat exchanger in the first embodiment of the present disclosure.

[0038] like Figure 1 As shown, the heat exchanger 101 of the first embodiment performs heat exchange between the gas G supplied from the outside and the refrigerant R. The heat exchanger 101 includes a heat transfer tube 102 and a plate fin 103. In the following description, the flow of the gas G that performs heat exchange in the heat exchanger is simply referred to as airflow. In addition, the direction in which the gas G flows is referred to as a first direction D1, the upstream side of the airflow is referred to as a first direction upstream side D1u, and the downstream side is referred to as a first direction downstream side D1d.

[0039] The heat transfer tube 102 is arranged in the airflow. The heat transfer tube 102 extends in the second direction D2 intersecting the first direction D1. A plurality of heat transfer tubes 102 are arranged in the airflow at intervals from each other. The plurality of arranged heat transfer tubes 102 constitute a heat transfer tube group 105. The heat transfer tubes 102 of the heat transfer tube group 105 illustrated in the present embodiment are all of the same shape, and the refrigerant R flows therein. The second direction D2 in the present embodiment illustrates a direction perpendicular to the first direction D1, but is not limited to perpendicular. In addition, in the following description, the direction intersecting the first direction D1 and the second direction D2 is referred to as a third direction D3 (refer to Figure 2 ).

[0040] Figure 2 It is along Figure 1 Cross-sectional view along line II-II.

[0041] like Figure 2 As shown, the heat transfer tubes 102 constituting the heat transfer tube group 105 are arranged in a so-called staggered arrangement. In other words, the heat transfer tubes 102 of the heat transfer tube group 105 are arranged in a rhombic grid. That is, a plurality of heat transfer tubes 102 of the heat transfer tube group 105 are arranged alternately and staggered in the first direction D1 and the third direction D3.

[0042] The heat transfer tubes 102 of the heat transfer tube group 105 of the present embodiment are formed into a first column C1 and a second column C2 extending in the first direction D1, and these first column C1 and second column C2 are alternately arranged in the third direction D3. In addition, the heat transfer tubes 102 of the first column C1 are arranged at intervals of a distance L1 in the first direction D1. The heat transfer tubes 102 of the second column C2 are arranged at intervals of a distance L1 in the first direction D1, and are arranged to be offset by a distance L2 which is half of the distance L1 in the first direction D1 relative to the positions of the heat transfer tubes 102 of the first column C1. In addition, in the following description, with respect to the heat transfer tubes 102, the structure arranged in the first direction D1 is sometimes referred to as a column (C), and the structure arranged in the third direction D3 is sometimes referred to as a stage (S). The heat transfer tube group 105 of the present embodiment has a plurality of columns and a plurality of stages of heat transfer tubes 102. In addition, for the convenience of illustration, in Figure 2 In FIG. 1 , in order to indicate the columns C ( C1 , C2 ) and the stages S, reference numerals are given to axes passing through the centers of the heat transfer tubes 102 constituting these.

[0043] The plate fins 103 are arranged in a manner extending in the first direction D1 and spanning over the plurality of heat transfer tubes 102. The plate fins 103 are arranged in a plurality of spaces in the second direction D2 (see Figure 1 ). The plurality of plate fins 103 in this embodiment are each formed in a thin plate shape and are arranged at equal intervals in the second direction D2. The above-mentioned airflow flows between these plate fins 103 from the first direction upstream side D1u to the first direction downstream side D1d.

[0044] The plate fin 103 is provided with a slit 104. The slit 104 extends in the third direction D3. More specifically, the slit 104 is formed in a manner of transversely crossing the plate fin 103 in the third direction D3. A plurality of slits 104 are arranged at intervals in the first direction D1. These plurality of slits 104 penetrate in the thickness direction of the plate fin 103, i.e., in the second direction D2. The slits 104 of the present embodiment are provided for each two stages of heat transfer pipes 102 adjacent in the first direction D1 of the corresponding heat transfer pipe group 105.

[0045] The plurality of slits 104 are in a sawtooth shape that extends alternately and obliquely toward the upstream side D1u in the first direction and the downstream side D1d in the first direction. The sawtooth periods of the plurality of slits 104 are consistent with each other. In other words, the positions of the convex portions 106 formed in a convex shape toward the upstream side D1u in the first direction and the concave portions 107 formed in a concave shape toward the downstream side D1d in the first direction are consistent with each other in the third direction D3. In addition, the sawtooth period of the slits 104 illustrated in the present embodiment is consistent with the arrangement period of the heat transfer tubes 102 arranged at equal intervals in the third direction D3. In addition, the sawtooth amplitude of the slits 104 is constant.

[0046] The slit 104 extends toward the upstream side D1u in the first direction at a position between the heat transfer tubes 102 that are adjacent to the slit 104 in the third direction D3 at a stage S that is adjacent to the slit 104 in the upstream side D1u in the first direction. In addition, the slit 104 extends toward the downstream side D1d in the first direction at a position between the heat transfer tubes 102 that are adjacent to the slit 104 in the third direction D3 at a stage S that is adjacent to the slit 104 in the downstream side D1d in the first direction. In the present embodiment, the position of the sawtooth top t in the third direction D3 coincides with the position of the heat transfer tube 102 in the third direction D3.

[0047] More specifically, in the present embodiment, the top t of the slit 104, i.e., the position of the folded back convex portion 106 in the third direction D3, is consistent with the position of the center of the heat transfer tube 102 in the first row C1. Similarly, the top t of the slit 104, i.e., the folded back convex portion 107 in the third direction D3, is consistent with the position of the center of the heat transfer tube 102 in the second row C2. In addition, in the present embodiment, the distances in the first direction D1 between the top t and the heat transfer tube 102 that is arranged at the closest position to the top t in the first direction D1 are all the same. In addition, the folded back position of the convex portion 106 or the concave portion 107 is not limited to the case where it is consistent with the center position of the heat transfer tube 102, for example, it can also be slightly offset from the center position of the heat transfer tube 102.

[0048] The portion of the slit 104 extending toward the upstream side D1u in the first direction in the example of the present embodiment extends to a position closer to the upstream side D1u in the first direction than the center of the heat transfer tube 102 of the stage S adjacent to the slit 104 on the upstream side D1u in the first direction. On the other hand, the portion of the slit 104 extending toward the upstream side D1u in the first direction does not extend to a position closer to the upstream side D1u in the first direction than the heat transfer tube 102 of the stage adjacent to the slit 104 on the upstream side D1u in the first direction. That is, the slit 104 is located at the same position as the point P1 closest to the upstream side D1u in the first direction or at a position closer to the downstream side D1d in the first direction.

[0049] Similarly, the portion of the slit 104 illustrated in the present embodiment extending toward the downstream side D1d in the first direction extends to a position closer to the downstream side D1d in the first direction than the center of the heat transfer tube 102 of the stage S adjacent to the slit 104 on the downstream side D1d in the first direction. On the other hand, the portion of the slit 104 extending toward the downstream side D1d in the first direction does not extend to a position closer to the downstream side D1d in the first direction than the heat transfer tube 102 of the stage S adjacent to the slit 104 on the downstream side D1d in the first direction. That is, the slit 104 is located at the same position as the point P2 of the heat transfer tube 102 of the stage S adjacent to the downstream side D1d in the first direction, which is closest to the downstream side D1d in the first direction, or at a position D1u on the upstream side in the first direction.

[0050] (Effect)

[0051] In the heat exchanger 101 of the first embodiment described above, the plate fin 103 has a plurality of slits 104 extending in the third direction D3 and arranged at intervals in the first direction D1. The plurality of slits 104 are in a sawtooth shape extending alternately and obliquely toward the upstream side D1u in the first direction and the downstream side D1d in the first direction, and the periods of the sawtooth shapes are consistent with each other.

[0052] Therefore, when the gas G flows from the upstream side D1u in the first direction to the downstream side D1d in the first direction, the airflow is disturbed by the slits 104, and the temperature boundary layer of the airflow can be thinned, so that the temperature gradient from the plate fin 103 can be steepened and the heat exchange amount can be increased. In addition, by forming the slits 104 into a sawtooth shape, the length of the slits 104 can be increased compared to the case where the slits 104 are formed into a straight line, so the plate fin 103 can be made lighter. In addition, since the sawtooth period of the plurality of slits 104 extending in the third direction D3 is consistent, the distance between the adjacent slits 104 in the first direction D1 can be made uniform, and the contact area between the airflow and the plate fin can be ensured. As a result, the development of the temperature boundary layer can be reduced and the reduction in the heat exchange amount can be suppressed.

[0053] In the heat exchanger 101 of the first embodiment, the heat transfer tubes 102 are further arranged in a staggered manner, and the slits 104 extend toward the first direction upstream side D1u between a plurality of heat transfer tubes 102 adjacent to the slits 104 in the first direction upstream side D1u and arranged in the third direction D3.

[0054] Thus, when the heat transfer tubes 102 are arranged in a staggered manner, the distance between the heat transfer tube 102 arranged one stage upstream of the first direction D1u and the slit 104 on the first direction downstream side D1d of the heat transfer tube 102 can be reduced. Therefore, the development of the temperature boundary layer on the first direction downstream side D1d of the heat transfer tube 102 can be suppressed, and the heat exchange amount can be increased.

[0055] In the heat exchanger 101 of the first embodiment, further, the position of the sawtooth top t in the third direction D3 coincides with the position of the heat transfer tube 102 in the third direction D3.

[0056] Thus, the distance between the staggered heat transfer tubes 102 and the slits 104 can be made more uniform.

[0057] In the heat exchanger 101 of the first embodiment, further, slits 104 are provided corresponding to every two stages of heat transfer tubes 102 arranged in the third direction D3 and adjacent to each other in the first direction D1.

[0058] Thereby, the amount of heat exchange can be increased more effectively.

[0059] (Modification of the first embodiment)

[0060] The width dimension of the slit 104 in the first embodiment in the first direction D1 may be narrower as the airflow velocity is higher and wider as the airflow velocity is lower, thereby more effectively suppressing the development of the temperature boundary layer even when the airflow velocity is low.

[0061] Second Implementation Method

[0062] Next, a second embodiment of the present disclosure will be described based on the drawings. A heat exchanger 201 of the second embodiment has a protrusion added to the heat exchanger 101 of the first embodiment described above. Figure 1 , and the same parts as those in the above-mentioned first embodiment are marked with the same figure marks and the description repeated in the first embodiment is omitted.

[0063] Figure 3 The heat exchanger in the second embodiment of the present disclosure is equivalent to Figure 2 sectional view of .

[0064] like Figure 1 , Figure 3As shown, the heat exchanger 201 in the second embodiment performs heat exchange between the gas G supplied from the outside and the refrigerant R, similarly to the heat exchanger 101 in the first embodiment. The heat exchanger 201 includes a heat transfer tube 102 , a plate fin 103 , and a protrusion 110 .

[0065] Figure 4 Yes Figure 3 An enlarged view of the main part of the image.

[0066] like Figure 3 , Figure 4 As shown, the protrusion 110 protrudes from the plate fin 103 in the second direction D2 and extends along the first direction D1. The protrusion 110 of this embodiment extends in a manner that crosses the plate fins 103 adjacent in the second direction D2. The protrusions 110 are arranged 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 arranged at a distance 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 arranged at a distance L3 in the third direction D3.

[0067] The interval L3 is smaller than the outer diameter R1 of the heat transfer tube 102. The case where the interval L3 of this embodiment is half the size of the outer diameter R1 of the heat transfer tube 102 is illustrated. Moreover, the length of the protrusion 110 in the first direction D1 can be any length as long as it can protrude longer than the heat transfer tube 102 in the first direction. In addition, the thickness of the protrusion 110 in the third direction D3 is smaller than the thickness of the tube wall of the heat transfer tube 102. In this embodiment, the case where the thickness of the protrusion 110 is about half the thickness of the tube wall of the heat transfer tube 102 is illustrated, but it is not limited to this.

[0068] In this embodiment, the case where the paired protrusions 110 are arranged at the same interval L3 is described, but the intervals between the paired protrusions 110 may be different at the first direction upstream side D1u and the first direction downstream side D1d. In addition, the case where the protrusions 110 of the second embodiment are formed in a flat plate shape extending along the first direction D1 when viewed from the second direction D2 is illustrated, but it is not limited to a flat plate shape, and may be, for example, a slightly curved shape.

[0069] (Effect)

[0070] In the second embodiment, the heat exchanger 201 includes the paired protrusions 110 on the upstream side D1u in the first direction and the downstream side D1d in the first direction of the heat transfer tube 102 .

[0071] As a result, the gas flows along the first direction D1 outside the third direction D3 of the paired protrusions 110, so that the flow path area of ​​the first direction upstream side D1u and the first direction upstream side D1u of the heat transfer tube 102 can be reduced to increase the flow rate of the gas. Therefore, in addition to suppressing the development of the temperature boundary layer by the slit 104, the development of the temperature boundary layer on the plate fin 103 can also be suppressed.

[0072] Furthermore, the heat transfer area of ​​the heat transfer tube 102 can be enlarged by the protrusions 110 , so that the heat exchange amount can be further increased.

[0073] 《First Modification of Second Embodiment》

[0074] Figure 5 The heat exchanger in the first modified example of the second embodiment of the present disclosure is equivalent to Figure 4 Magnified image of .

[0075] The above-mentioned second embodiment has been described in which the protrusion 110 is formed integrally with the heat transfer tube 102. However, the protrusion 110 is not limited to being formed integrally with the heat transfer tube 102. For example, Figure 5 As shown in the figure, the protrusion 110 is formed by cutting out the plate fin 103 or the like.

[0076] <<Second Modification Example of Second Implementation>>

[0077] Figure 6 The heat exchanger in the second modification of the second embodiment of the present disclosure is equivalent to Figure 4 Magnified image of .

[0078] The protrusion 110 of the second embodiment described above is formed integrally with the heat transfer tube 102 , and therefore the protrusion 110 needs to be attached by welding, bonding, or the like after the heat transfer tube 102 is passed through the plate fin 103 .

[0079] However, if Figure 6 As shown in the second modification of the second embodiment, by forming the protrusion through hole 111 that allows the protrusion 110 to pass through in the second direction D2, the heat transfer tube 102 can pass through the plate fin 103 even after the protrusion 110 is attached to the heat transfer tube 102. Thus, the heat exchanger 201 including the protrusion 110 can be easily assembled.

[0080] 《Third Modification of Second Embodiment》

[0081] Figure 7 The heat exchanger in the third modified example of the second embodiment of the present disclosure is equivalent to Figure 4 Magnified image of .

[0082] In the second embodiment described above, the case where the protrusion 110 is formed integrally with the heat transfer tube 102 has been described, but the present invention is not limited to this structure.

[0083] For example, you can also Figure 7 As in the third modified example of the second embodiment shown in the figure, a gap G1 through which gas can flow is provided between the protrusion 110 and the heat transfer tube 102. The length of the gap G1 in the first direction D1 may also be set to the thickness of the tube wall of the heat transfer tube 102. In addition, the protrusion 110 of the third modified example of the second embodiment may be formed by cutting from the plate fin 103 in the same manner as the protrusion 110 of the first modified example of the second embodiment. For example, a protrusion through hole through which the protrusion 110 can pass may be provided as in the second modified example of the second embodiment, and after the protrusion 110 is inserted into the protrusion through hole, the protrusion 110 and the plate fin 103 are fixed by welding or bonding.

[0084] By configuring as in the third modified example of the second embodiment, for example, even when flanges are applied to the plate fins 103 around the heat transfer tubes 102, the protrusions 110 can be easily provided. In addition, since the gas G flows through the gap G1 between the protrusions 110 and the heat transfer tubes 102, the stagnant area of ​​the gas G between the paired protrusions 110 is reduced, and as a result, the heat transfer effect can be promoted.

[0085] 《Fourth Modification of Second Embodiment》

[0086] Figure 8 The heat exchanger in the fourth modified example of the second embodiment of the present disclosure is equivalent to Figure 4 Magnified image of .

[0087] In the second embodiment described above, the protrusions 110 are provided on the upstream side D1u in the first direction and the downstream side D1d in the first direction of the heat pipe 102. However, for example, the protrusions 110 may be provided on a portion of the heat pipes 102 on the downstream side D1d in the first direction of the heat pipe group 105. Figure 8 As shown in the fourth modified example of the second embodiment, a protrusion 112 protrudes from the heat transfer tube 102 in a direction away from the heat transfer tube 102 in the third direction D3. By providing such a protrusion 112, the heat transfer area of ​​the heat transfer tube 102 can be expanded, so that the amount of heat transfer in the heat transfer tube 102 in the first direction downstream side D1d where the temperature difference between the gas G and the refrigerant R is small can be ensured. In addition, the shape of the protrusion 112 can be any shape as long as it can expand the heat transfer area, and is not limited to Figure 8 Shape shown.

[0088] 《Fifth Modification of Second Embodiment》

[0089] Fig. 9 The heat exchanger in the fifth modified example of the second embodiment of the present disclosure is equivalent to Figure 2 sectional view of .

[0090] In the second embodiment described above, the heat transfer tubes 102 are described as being arranged in a staggered manner when viewed from the second direction D2. However, the heat transfer tubes 102 are not limited to being arranged in a staggered manner. Fig. 9 As in the fifth modification of the second embodiment shown in FIG. 1 , the heat transfer tubes 102 are arranged in a lattice arrangement of a so-called square lattice or a rectangular lattice when viewed from the second direction D2.

[0091] In the case of the staggered arrangement, the slits 104 are arranged at intervals in the first direction D1 at every two stages in the stages S of the heat transfer tubes 102 arranged along the third direction D3. Fig. 9 As shown, in the case of a lattice arrangement of a square lattice or a rectangular lattice, the intervals in the first direction D1 of the zigzag slits 104 may be provided for each stage S of the heat transfer pipes 102 .

[0092] By disposing the slits 104 in this way, in the case of the above-mentioned square lattice or rectangular lattice arrangement, the heat transfer coefficient in the air flow direction, that is, the first direction D1 in the heat exchanger 201 can be averaged, and heat exchange can be performed efficiently.

[0093] (Other Modifications of Second Embodiment)

[0094] The width dimension of the slit 104 in the first direction D1 in the second embodiment and each modified example described above may also be the same as the first embodiment, for example, formed to be narrower as the flow velocity of the airflow is higher, and wider as the flow velocity of the airflow is lower. In addition, the length of the protrusion 110 in the first direction D1 may also be formed to be shorter as the flow velocity of the airflow is higher, and longer as the flow velocity of the airflow is lower. Thus, even when the flow velocity of the airflow is low, the development of the temperature boundary layer can be more effectively suppressed.

[0095] 《Third Implementation Mode》

[0096] Next, a heat exchanger according to a third embodiment of the present disclosure will be described based on the drawings. The shape of the plate fins of the heat exchanger 301 according to the third embodiment is different from that of the heat exchanger 101 according to the first embodiment described above. Figure 1 , and the same parts as those in the above-mentioned first embodiment are marked with the same figure marks for description.

[0097] like Figure 1As shown, the heat exchanger 301 of the third embodiment performs heat exchange between the gas G supplied from the outside and the refrigerant R. The heat exchanger 301 includes a heat transfer tube 102 and a plate fin 303. In addition, the flow of the gas G that performs heat exchange in the heat exchanger 301 is simply referred to as an airflow. In addition, the direction in which the gas G flows is referred to as a first direction D1, the upstream side of the airflow is referred to as a first direction upstream side D1u, and the downstream side is referred to as a first direction downstream side D1d.

[0098] The heat transfer tube 102 is arranged in the air flow. The heat transfer tube 102 extends in the second direction D2 intersecting the first direction D1. A plurality of heat transfer tubes 102 are arranged in the air flow at intervals. The plurality of heat transfer tubes 102 are arranged to form a heat transfer tube group 105. The heat transfer tubes 102 of the heat transfer tube group 105 illustrated in this embodiment are all of the same shape, and the refrigerant R flows therein. The second direction D2 in this embodiment illustrates a direction perpendicular to the first direction D1, but is not limited to perpendicular. In addition, in the following description, the direction intersecting the first direction D1 and the second direction D2 is referred to as a third direction D3.

[0099] Fig.10 It is along Figure 1 Cross-sectional view of line XX.

[0100] like Fig.10 As shown, the heat transfer tubes 102 constituting the heat transfer tube group 105 are arranged in a so-called staggered arrangement. In other words, the heat transfer tubes 102 of the heat transfer tube group 105 are arranged in a rhombic grid with respect to the first direction D1. In other words, a plurality of heat transfer tubes 102 of the heat transfer tube group 105 are arranged alternately and staggered in the first direction D1 and the third direction D3.

[0101] The heat transfer tubes 102 of the heat transfer tube group 105 of the present embodiment are formed into a first row C1 and a second row C2 extending in the first direction D1, and these first row C1 and second row C2 are alternately arranged in the third direction D3. In addition, the heat transfer tubes 102 of the first row C1 are arranged at intervals of a distance L1 in the first direction D1. The heat transfer tubes 102 of the second row C2 are arranged at intervals of a distance L1 in the first direction D1, and are arranged at a distance L2 that is half of the distance L1 relative to the positions of the heat transfer tubes 102 of the first row C1 in the first direction D1. In addition, in the following description, with respect to the heat transfer tubes 102, the structure arranged in the first direction D1 is sometimes referred to as a row (C), and the structure arranged in the third direction D3 is sometimes referred to as a stage (S). The heat transfer tube group 105 of the present embodiment has a plurality of rows and stages of heat transfer tubes 102. In addition, in the third embodiment, only two rows of heat transfer tubes 102 are shown, but three or more rows may be provided.

[0102] The plate fins 303 are arranged in a manner extending in the first direction D1 and spanning over the plurality of heat transfer tubes 102. A plurality of plate fins 103 are arranged at intervals in the second direction D2. The plurality of plate fins 103 in this embodiment are each formed in a thin plate shape and are arranged at equal intervals in the second direction D2. The airflow flows between the plate fins 103 from the upstream side D1u in the first direction to the downstream side D1d in the first direction.

[0103] The plate fin 103 has a hole 304 that passes through in the second direction D2. The holes 304 are respectively formed on the upstream side D1u of the first direction of the plurality of heat transfer tubes 102. The holes 304 in the third embodiment are rectangular with the first direction D1 as the long side direction when viewed from the second direction D2. In addition, when the holes 304 in the third embodiment are viewed from the second direction D2, the center of the heat transfer tube 102 adjacent to the downstream side D1d in the first direction is located on the extension line of the axis passing through the center of the third direction D3 of the above-mentioned rectangle. In addition, the example of the case where the center position of the hole 304 in the third embodiment is the same position in the first direction D1 as the center position of the heat transfer tube 102 of the row C adjacent to the row C in the third direction D3 relative to which the hole 304 is formed is illustrated, but these center positions may also be offset in the first direction D1.

[0104] The hole 304 is formed in the area of ​​the plate fin 303 that is determined to have a smaller contribution to heat transfer through a previously performed optimization analysis or the like. In the third embodiment, the short side of the rectangular hole 304 is formed to be smaller than the outer diameter R1 of the heat transfer tube 102. In addition, in the third embodiment, the short side of the rectangular hole 304 is formed to be 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 the inner diameter R2 of the heat transfer tube 102. The shape of the hole 304 is not limited to the above-mentioned shape and size as long as it includes the shape of the area of ​​the plate fin 303 that is determined to have a smaller contribution to heat transfer through an optimization analysis or the like. When the shape of the hole 304 is set to the above-mentioned rectangular shape, it is advantageous in that it can be easily processed.

[0105] (Effect)

[0106] In the heat exchanger 301 of the third embodiment, a plurality of heat transfer tubes 102 are arranged in the air flow and extend along the second direction D2, forming a staggered arrangement alternately staggered in the first direction D1 and the third direction D3. The plate fins 303 are arranged in a manner extending in the first direction D1 and spanning 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 fins 303 have holes 304 penetrating in the second direction D2 on the upstream side D1u of the plurality of heat transfer tubes 102 in the first direction.

[0107] Thus, when the gas G flows from the upstream side D1u in the first direction to the downstream side D1d in the first direction, the airflow is disturbed by the hole 304, and the temperature boundary layer of the airflow can be thinned, so that the temperature gradient from the plate fin 303 can be steepened and the heat exchange amount can be increased. In addition, since the hole 304 penetrates the plate fin 303, the plate fin 303 can be made lighter according to the opening area of ​​the hole 304 compared with a case where the hole 304 is not provided. As a result, the development of the temperature boundary layer can be reduced and the reduction in the heat exchange amount can be suppressed.

[0108] Furthermore, since it is sufficient to form only the hole 304 penetrating in the second direction D2 in the plate fin 303 , the manufacturing is easy and the complication of the processing steps can be suppressed.

[0109] 《Fourth Implementation Mode》

[0110] Next, a fourth embodiment of the present disclosure will be described based on the drawings. A heat exchanger 401 of the fourth embodiment has a protrusion added to the heat exchanger 301 of the third embodiment described above. Figure 1 , and the same parts as those in the third embodiment are marked with the same figure marks and described, and the description repeated in the third embodiment is omitted.

[0111] Fig.11 The heat exchanger in the fourth embodiment of the present disclosure is equivalent to Fig.10 A cross-sectional view of Figure 1 , Fig.11 As shown, the heat exchanger 401 of the fourth embodiment performs heat exchange between the gas G supplied from the outside and the refrigerant R, similarly to the heat exchanger 101 of the first embodiment. The heat exchanger 401 includes a heat transfer tube 102 , a plate fin 303 , and a protrusion 110 .

[0112] Fig.12 Yes Fig.11 An enlarged view of the main part of the image.

[0113] like Fig.11 , Fig.12 As shown, the protrusion 110 protrudes from the plate fin 303 in the second direction D2 and extends along the first direction D1. The protrusion 110 of the fourth embodiment extends in a manner that crosses the plate fin 303 adjacent in the second direction D2. The protrusions 110 are arranged 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 arranged at a distance 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 arranged at a distance L3 in the third direction D3.

[0114] The interval L3 is smaller than the outer diameter of the heat transfer tube 102. In this embodiment, the interval L3 is illustrated as being half the size of the outer diameter of the heat transfer tube 102. In addition, the length of the protrusion 110 in the first direction D1 can be any length as long as it can protrude longer than the heat transfer tube 102 in the first direction. In addition, the thickness of the protrusion 110 in the third direction D3 is smaller than the thickness of the tube wall of the heat transfer tube 102. In this embodiment, the thickness of the protrusion 110 is illustrated as being about half the thickness of the tube wall of the heat transfer tube 102, but it is not limited thereto.

[0115] In the fourth embodiment, the case where the paired protrusions 110 are arranged at the same interval L3 is described, but the intervals between the paired protrusions 110 may be different at the upstream side D1u in the first direction and the downstream side D1d in the first direction. In addition, the case where the protrusions 110 of the fourth embodiment are formed in a flat plate shape extending along the first direction D1 when viewed from the second direction D2 is illustrated, but it is not limited to a flat plate shape, and may be, for example, a slightly curved shape.

[0116] (Effect)

[0117] In the fourth embodiment, the heat exchanger 401 includes the paired protrusions 110 on the upstream side D1u in the first direction and the downstream side D1d in the first direction of the heat transfer tube 102 .

[0118] As a result, the gas flows along the first direction D1 outside the third direction D3 of the paired protrusions 110, so that the flow path area of ​​the first direction upstream side D1u and the first direction upstream side D1u of the heat transfer tube 102 can be reduced to increase the flow rate of the gas. Therefore, in addition to suppressing the development of the temperature boundary layer by using the holes 304, the development of the temperature boundary layer on the plate fin 103 can also be suppressed.

[0119] Furthermore, the heat transfer area of ​​the heat transfer tube 102 can be enlarged by the protrusions 110 , so that the heat exchange amount can be further increased.

[0120] 《First Modification of Fourth Embodiment》

[0121] Fig.13 The heat exchanger in the first modified example of the fourth embodiment of the present disclosure is equivalent to Fig.12 Magnified image of .

[0122] The above fourth embodiment has been described in which the protrusion 110 is formed integrally with the heat transfer tube 102. However, the protrusion 110 is not limited to being formed integrally with the heat transfer tube 102. For example, Fig.13 Like the protrusion 110 shown in the figure, it is formed by cutting out from the plate fin 303 or the like.

[0123] Second Modification of the Fourth Embodiment

[0124] Fig.14 The heat exchanger in the second modified example of the fourth embodiment of the present disclosure is equivalent to Fig.12 Magnified image of .

[0125] Since the protrusion 110 of the fourth embodiment is formed integrally with the heat transfer tube 102 , it is necessary to attach the protrusion 110 by welding, bonding, or the like after the heat transfer tube 102 is passed through the plate fin 303 .

[0126] However, if Fig.14 As shown in the second modified example of the fourth embodiment, by forming the protrusion through hole 111 that allows the protrusion 110 to pass through in the second direction D2, the heat transfer tube 102 can pass through the plate fin 303 even after the protrusion 110 is attached to the heat transfer tube 102. Thus, the heat exchanger 401 including the protrusion 110 can be easily assembled.

[0127] 《Third Modification of Fourth Embodiment》

[0128] Fig.15 The heat exchanger in the third modified example of the fourth embodiment of the present disclosure is equivalent to Fig.12 Magnified image of .

[0129] In the fourth embodiment described above, the case where the protrusion 110 is formed integrally with the heat transfer tube 102 has been described, but the present invention is not limited to this structure.

[0130] For example, you can also Fig.15 As in the third variant of the fourth embodiment shown in the figure, a gap G1 through which gas can flow is provided between the protrusion 110 and the heat transfer tube 102. The length of the gap G1 in the first direction D1 may also be set to the thickness of the tube wall of the heat transfer tube 102. In addition, the protrusion 110 of the third variant of the fourth embodiment may be formed by cutting from the plate fin 303 in the same manner as the protrusion 110 of the first variant of the fourth embodiment. For example, a protrusion through hole through which the protrusion 110 can pass may be provided as in the second variant of the fourth embodiment, and after the protrusion 110 is inserted into the protrusion through hole, the protrusion 110 and the plate fin 303 are fixed by welding or bonding.

[0131] By configuring as in the third modified example of the fourth embodiment, for example, even when flanges are applied to the plate fins 303 around the heat transfer tubes 102, the protrusions 110 can be easily provided. In addition, since the gas flows through the gap G1 between the protrusions 110 and the heat transfer tubes 102, the stagnant area of ​​the gas between the paired protrusions 110 is reduced, and as a result, the heat transfer effect can be promoted.

[0132] 《Fourth Modification of Fourth Embodiment》

[0133] Fig.16 The heat exchanger in the fourth modification of the fourth embodiment of the present disclosure is equivalent to Fig.12 Magnified image of .

[0134] In the fourth embodiment described above, the protrusions 110 are provided on the upstream side D1u in the first direction and the downstream side D1d in the first direction of the heat pipe 102. However, for example, the protrusions 110 may be provided on a portion of the heat pipes 102 on the downstream side D1d in the first direction of the heat pipe group 105. Fig.16 As shown in the fourth modification of the fourth embodiment, a protrusion 112 protrudes from the heat transfer tube 102 in a direction away from the heat transfer tube 102 in the third direction D3. By providing such a protrusion 112, the heat transfer area of ​​the heat transfer tube 102 can be expanded, so that the amount of heat transfer in the heat transfer tube 102 in the first direction downstream side D1d where the temperature difference between the gas G and the refrigerant R is small can be ensured. In addition, the shape of the protrusion 112 can be any shape as long as it can expand the heat transfer area, and is not limited to Fig.16 Shape shown.

[0135] (Other Modifications of the Fourth Embodiment)

[0136] In the fourth embodiment and its variants, the length of the protrusion 110 in the first direction D1 may be shorter as the velocity of the airflow is higher and longer as the velocity of the airflow is lower. Thus, even when the velocity of the airflow is low, the development of the temperature boundary layer can be more effectively suppressed.

[0137] 《Other Implementation Methods》

[0138] The present disclosure is not limited to the configurations of the above-described embodiments and modifications, and design changes can be made within a scope not departing from the gist of the disclosure.

[0139] For example, the slits 104 in the first and second embodiments are formed like triangular waves, but the edge portion forming the slits 104 is not limited to being formed in a straight line when viewed from the second direction D2. For example, it can also be a shape formed by combining a straight line and a curve. In addition, the number of rows and the number of stages of the heat transfer tubes 102 constituting the heat transfer tube group 105 can be multiple, and are not limited to the number of rows and the number of stages in the above-mentioned embodiments and modifications.

[0140] <Note>

[0141] The heat exchangers 101 , 201 , 301 , and 401 described in the above-mentioned embodiments can be understood, for example, as follows.

[0142] (1) According to a first embodiment, a heat exchanger comprises: a heat transfer tube 102 arranged in a gas flow and extending in a second direction D2 intersecting a first direction D1 of the gas flow and arranged at intervals from each other; and a plate fin 103 provided in a manner extending in the first direction D1 and spanning over the plurality of heat transfer tubes 102 and arranged at intervals from each other in the second direction D2, the plate fin 103 comprising slits 104 extending in a third direction D3 intersecting both the first direction D1 and the second direction D2 and arranged at intervals from each other in the first direction D1, the plurality of slits 104 being in a sawtooth shape extending alternately and obliquely toward an upstream side D1u and a downstream side D1d in the first direction D1 of the gas flow, and the periods of the sawtooth shapes are consistent with each other.

[0143] Thus, the airflow is disturbed by the slits 104, and the temperature boundary layer of the airflow can be thinned, so that the temperature gradient from the plate fins 103 can be steepened and the heat exchange amount can be increased. In addition, the length of the slits 104 can be increased by making the slits 104 serrated, so the plate fins 103 can be lightweight.

[0144] (2) According to a second embodiment, based on the heat exchanger of (1), the heat transfer tubes 102 are arranged in a staggered manner alternately 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 102 arranged in the third direction D3 in such a manner that the slits 104 are adjacent to the upstream side D1u in the first direction D1.

[0145] Thus, when the heat transfer tubes 102 are arranged in a staggered manner, the distance between the heat transfer tube 102 arranged one stage upstream D1u in the first direction and the slit 104 on the downstream side D1d in the first direction of the heat transfer tube 102 can be reduced.

[0146] (3) According to a third aspect, in the heat exchanger of (2), a position of the zigzag top t in the third direction D3 coincides with a position of the heat transfer tube 102 in the third direction D3.

[0147] Thus, the distance between the staggered heat transfer tubes 102 and the slits 104 can be made more uniform.

[0148] (4) According to a fourth aspect, in the heat exchanger of (2) or (3), the slits 104 are provided for every two stages of the heat transfer tubes 102 arranged in the third direction D3 and adjacent to each other in the first direction D1.

[0149] Thereby, the amount of heat exchange can be increased more effectively.

[0150] (5) According to a fifth embodiment, based on any one of the heat exchangers of (1) to (4), there is provided a pair of protrusions 110 protruding from the plate fin 103 in the second direction D2, extending in the first direction D1 and spaced apart in the third direction D3, and the pair of protrusions 110 are respectively located on the upstream side D1u and the downstream side D1d of the heat transfer tube 102 in the first direction D1.

[0151] Thus, the gas G flows along the first direction D1 outside the third direction D3 of the paired protrusions 110, so that the flow path area of ​​the first direction upstream side D1u and the first direction downstream side D1d of the heat transfer tube 102 can be reduced to increase the flow rate of the gas G. Therefore, the development of the temperature boundary layer on the plate fin 103 can be suppressed.

[0152] (6) According to a sixth aspect, in the heat exchanger of (5), a gap G1 through which the gas G can flow is provided between the protrusion 110 and the heat transfer tube 102 .

[0153] This makes it easy to provide the protrusions 110. In addition, since the gas G flows through the gap G1 between the protrusions 110 and the heat transfer tube 102, the stagnant area of ​​the gas G between the paired protrusions 110 is reduced, resulting in the improvement of the heat transfer effect.

[0154] (7) According to a seventh aspect, in the heat exchanger of (5) or (6), a protrusion 112 is provided that protrudes toward the third direction D3 from a portion of the heat transfer tubes 102 on the downstream side D1d in the first direction D1.

[0155] This can increase the heat transfer area of ​​the heat transfer tube 102 , and thus ensure the heat transfer amount of the heat transfer tube 102 in the downstream side D1d in the first direction where the temperature difference between the gas G and the refrigerant R is small.

[0156] (8) According to the eighth aspect, the heat exchanger comprises: a plurality of heat transfer tubes 102 arranged in the gas flow of the gas G, extending in the second direction D2 intersecting the first direction D1 in which the gas G flows, and arranged in a staggered manner so as to be alternately staggered in the first direction D1 and in a third direction D3 intersecting both the first direction D1 and the second direction D2; and a plurality of plate fins 303 arranged in the second direction D2 so as to extend in the first direction D1 and straddle the plurality of heat transfer tubes 102, and the plate fins 303 are arranged at intervals in the second direction D2, and the plate fins 303 are provided on the first direction upstream side D1u of the plurality of heat transfer tubes 102 and penetrate in the second direction D2. Thus, when 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 the temperature boundary layer of the gas flow can be thinned, so that the temperature gradient from the plate fins 303 can be steepened, thereby increasing the amount of heat exchange. Furthermore, since the holes 304 penetrate the plate fin 303 , the plate fin 303 can be made lighter in weight in accordance with the opening area of ​​the holes 304 , compared with a case where the holes 304 are not provided.

[0157] (9) According to the ninth embodiment, based on the heat exchanger of (8), there is a pair of protrusions 110 protruding from the plate fin 103 in the second direction D2, extending in the first direction D1 and arranged at intervals in the third direction D3, and the pair of protrusions 110 are respectively located on the upstream side D1u and the downstream side D1d of the heat transfer tube 102 in the first direction D1.

[0158] Thus, the gas G flows along the first direction D1 outside the third direction D3 of the paired protrusions 110, thereby reducing the flow path area of ​​the first direction upstream side D1u and the first direction downstream side D1d of the heat transfer tube 102 and increasing the flow velocity of the gas. Therefore, the development of the temperature boundary layer on the plate fin 103 can be suppressed.

[0159] (10) According to the tenth aspect, in the heat exchanger of (9), a gap G1 through which the gas G can flow is provided between the protrusion 110 and the heat transfer tube 102 .

[0160] This makes it easy to provide the protrusions 110. In addition, since the gas G flows through the gap G1 between the protrusions 110 and the heat transfer tube 102, the stagnant area of ​​the gas G between the paired protrusions 110 is reduced, resulting in the improvement of the heat transfer effect.

[0161] (11) According to an eleventh aspect, in the heat exchanger of (9) or (10), a protrusion 112 is provided that protrudes toward the third direction D3 from a portion of the heat transfer tubes 102 on the downstream side D1d in the first direction D1.

[0162] This can increase the heat transfer area of ​​the heat transfer tube 102 , and thus ensure the heat transfer amount of the heat transfer tube 102 in the downstream side D1d in the first direction where the temperature difference between the gas G and the refrigerant R is small.

[0163] Possibility of Industrial Application

[0164] According to the heat exchanger of the above aspect, it is possible to increase the amount of heat exchange and reduce the weight.

[0165] Description of Reference Numerals

[0166] 101, 201, 301, 401…heat exchanger, 102…heat transfer tube, 103, 303…plate fin, 104…slit, 105…heat transfer tube group, 106…convex portion, 107…concave portion, 110…protrusion, 111…protrusion through hole, 112…protrusion, 304…hole, G…gas, G1…gap, R…refrigerant, t…top portion.

Claims

1. A heat exchanger comprising: a plurality of heat transfer tubes arranged in the gas flow, extending in a second direction intersecting the first direction of the gas flow and spaced apart from each other; and The plate fins are arranged so as to extend in the first direction and to cross over the plurality of the heat transfer tubes, and a plurality of the plate fins are arranged at intervals from each other in the second direction. The plate fin includes slits extending in a third direction intersecting both the first direction and the second direction, and a plurality of slits are arranged at intervals in the first direction. The plurality of slits are in a sawtooth shape that extends obliquely alternately toward the upstream side and the downstream side in the first direction of the gas flow, and the sawtooth shapes have the same period.

2. The heat exchanger according to claim 1, wherein: The heat transfer tubes are arranged in a staggered manner so as to be alternately staggered in the first direction and the third direction. The slit extends toward the upstream side in the first direction between the plurality of heat transfer tubes arranged in the third direction so as to be adjacent to the slit on the upstream side in the first direction.

3. The heat exchanger according to claim 2, wherein: The position of the sawtooth top in the third direction is consistent with the position of the heat transfer tube in the third direction.

4. The heat exchanger according to claim 2 or 3, wherein: The slits are provided corresponding to every two stages of the heat transfer tubes arranged in the third direction and adjacent to each other in the first direction.

5. The heat exchanger according to any one of claims 1 to 3, wherein: The heat exchanger includes a pair of protrusions that protrude from the plate fin in the second direction, extend in the first direction, and are spaced apart in the third direction. The paired protrusions are respectively located on the upstream side and the downstream side of the heat transfer tube in the first direction.

6. The heat exchanger according to claim 5, wherein: A gap through which the gas can flow is provided between the protrusion and the heat transfer tube.

7. The heat exchanger according to claim 5, wherein: The heat exchanger includes a protruding portion that protrudes toward the third direction from a portion of the heat transfer tubes on the downstream side in the first direction among the plurality of heat transfer tubes.

8. A heat exchanger comprising: a plurality of heat transfer tubes arranged in the gas flow, extending in a second direction intersecting a first direction of the gas flow, and arranged in a staggered manner so as to be alternately staggered in the first direction and in a third direction intersecting both the first direction and the second direction; and The plate fins are arranged so as to extend in the first direction and to cross over the plurality of the heat transfer tubes, and a plurality of the plate fins are arranged at intervals from each other in the second direction. The plate fin has holes penetrating in the second direction on the upstream side of the plurality of heat transfer tubes in the first direction.

9. The heat exchanger according to claim 8, wherein: The heat exchanger includes a pair of protrusions that protrude from the plate fin in the second direction, extend in the first direction, and are spaced apart in the third direction. The paired protrusions are respectively located on the upstream side and the downstream side of the heat transfer tube in the first direction.

10. The heat exchanger according to claim 9, wherein: A gap through which the gas can flow is provided between the protrusion and the heat transfer tube.

11. The heat exchanger according to claim 9 or 10, wherein: The heat exchanger includes a protruding portion that protrudes toward the third direction from a portion of the heat transfer tubes on the downstream side in the first direction among the plurality of heat transfer tubes.

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