HEAT EXCHANGER

Abstract

 This heat exchanger comprises: a pair of plates that face each other; and an inner fin which is provided between the plates and in which a fluid circulates. The inner fin has a plurality of offset fins which are arranged side by side in the flowing direction of the fluid and are provided such that the positions thereof are mutually offset in the width direction orthogonal to the flowing direction. The offset fins include: plate joint parts which are joined to the plates and have steps formed in the flowing direction; fin parts provided along the opposing direction of the plates and connected to the plate joint parts; and reception slopes which are provided to the plate joint parts obliquely to the flowing direction and which receive the fluid from the steps.

Description

Technical Field

[0001] The present disclosure relates to a heat exchanger.

Background Art

[0002] In the related art, a heat exchanger such as an oil cooler using offset fins as inner fins is known (for example, refer to PTL 1). This oil cooler includes a tube through which oil circulates inside and a cooling medium circulates outside, and offset fins that are arranged inside the tube to perform heat exchange between the oil and the cooling medium. The offset fins have a wavy cross-sectional shape perpendicular to a flowing direction of the oil in which convex portions are alternately positioned on one side and the other side.

Citation List

Patent Literature

[0003] [PTL 1] Japanese Unexamined Patent Application Publication No. 2012-17943

Summary of Invention

Technical Problem

[0004] In a heat exchanger using offset fins, a thermal boundary layer is formed on a fin wall surface between the fluids passing on both sides of the offset fins, where a high-temperature fluid such as oil and a low-temperature fluid such as a cooling medium exchange heat. The thermal boundary layer is a layer formed by a temperature gradient that occurs between the fluid heated or cooled at the fin wall surface and the fluid near the wall surface. The thickness of the thermal boundary layer increases due to heat exchange, and in a case where the temperature gradient in the fluid near the wall surface decreases, heat exchange is suppressed and heat transfer performance decreases, resulting in a decrease in heat exchange performance of the heat exchanger.

[0005] Therefore, an object of the present disclosure is to provide a heat exchanger that can suppress a decrease in heat transfer performance by reducing a thickness of a thermal boundary layer.

Solution to Problem

[0006] A heat exchanger according to an aspect of the present disclosure includes a pair of plates that face each other; and an inner fin which is provided between the pair of plates and in which a fluid circulates, in which the inner fin has a plurality of offset fins which are arranged side by side in a flowing direction of the fluid and are provided such that positions thereof are mutually offset in a width direction perpendicular to the flowing direction, and the offset fin includes a plate joint part which is joined to the plate and has a step formed in the flowing direction, a fin part which is provided along an opposing direction of the pair of plates and is connected to the plate joint part, and a reception slope which is provided to the plate joint part, obliquely to the flowing direction, and which receives the fluid from the step.

[0007] A heat exchanger according to another aspect of the present disclosure includes a pair of plates that face each other; and an inner fin which is provided between the pair of plates and in which a fluid circulates, in which the inner fin has a plurality of offset fins which are arranged side by side in a flowing direction of the fluid and are provided such that positions thereof are mutually offset in a width direction perpendicular to the flowing direction, and the offset fin includes a plate joint part which is joined to the plate, a fin part which is provided along an opposing direction of the pair of plates and is connected to the plate joint part, and a protrusion portion which is provided on the plate joint part and protrudes inward from the plate joint part.

[0008] A heat exchanger according to still another aspect of the present disclosure includes a pair of plates that face each other; and an inner fin which is provided between the pair of plates and in which a fluid circulates, in which the inner fin has a plurality of offset fins which are arranged side by side in a flowing direction of the fluid and are provided such that positions thereof are mutually offset in a width direction perpendicular to the flowing direction, and the offset fin includes a plate joint part which is joined to the plate, a fin part which is provided along an opposing direction of the pair of plates and is connected to the plate joint part, and a hole that is provided to the plate joint part and is recessed from the plate joint part toward the plate. Advantageous Effects of Invention

[0009] According to the present disclosure, a decrease in heat transfer performance can be suppressed by suppressing formation of a thermal boundary layer.

Brief Description of Drawings

[0010] 

Fig. 1 is a perspective view schematically illustrating a heat exchanger according to a first embodiment.

Fig. 2 is a perspective view illustrating an offset fin of the heat exchanger according to the first embodiment.

Fig. 3 is a two-sided view of the offset fin.

Fig. 4 is a sectional view of the offset fin.

Fig. 5 is an explanatory diagram regarding a flow of a fluid.

Fig. 6 is a perspective view illustrating an offset fin of a heat exchanger according to a second embodiment.

Fig. 7 is a perspective view illustrating a protrusion portion of the offset fin.

Fig. 8 is a two-sided view of the offset fin.

Fig. 9 is a perspective view illustrating an offset fin of a heat exchanger according to a third embodiment.

Fig. 10 is a plan view of the offset fin.

Fig. 11 is a sectional view of the offset fin.

Fig. 12 is an explanatory diagram regarding a flow of a fluid.

Description of Embodiments

[0011] Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to this embodiment. In addition, components in the embodiments described below include those that can be easily replaced by those skilled in the art, or those that are substantially the same. Furthermore, the components described below can be combined as appropriate, and in a case where there are a plurality of embodiments, the embodiments can be combined.

[First Embodiment]

[0012] A heat exchanger 1 according to a first embodiment is a heat exchanger having a stacked structure in which inner fins are provided between a pair of plates, and is a so-called plate heat exchanger. In the heat exchanger 1, heat exchange is performed between a high-temperature fluid and a low-temperature fluid that circulates inside the heat exchanger 1. Note that the fluid circulating inside the heat exchanger 1 may be a liquid or a gas, and is not particularly limited.

[0013] Fig. 1 is a perspective view schematically illustrating the heat exchanger according to the first embodiment. Fig. 2 is a perspective view illustrating the offset fin of the heat exchanger according to the first embodiment. Fig. 3 is a two-sided view of the offset fin. Fig. 4 is a sectional view of the offset fin. Fig. 5 is an explanatory diagram regarding a flow of the fluid.

(Heat Exchanger)

[0014] The heat exchanger 1 includes a plurality of plates 10 and inner fins 12 provided between the plates 10. The plate 10 is formed in a plate shape. The plurality of plates 10 are arranged at predetermined intervals in an opposing direction in which plate surfaces of the plates 10 face each other, that is, in a thickness direction. In the plate 10, a high-temperature fluid circulates through one side in the thickness direction, and a low-temperature fluid circulates through the other side in the thickness direction. The plate 10 is made of a metallic material with high heat transfer performance.

[0015] The inner fins 12 are provided between a pair of plates 10 that are adjacent to each other, and are joined to the plates 10 by brazing. That is, one side of the inner fins 12 in the thickness direction is joined to the plate 10 on one side, and the other side of the inner fins 12 in the thickness direction is joined to the plate on the other side. The inner fins 12 function as a strength member that supports the pair of plates 10. In addition, the inner fins 12 are provided with a flow path through which the fluid circulates. Therefore, the fluid circulates between the pair of plates 10 that face each other, that is, inside the inner fins 12.

[0016] The plurality of plates 10 and the inner fins 12 are alternately arranged and joined in the thickness direction. Therefore, the flow paths formed by the inner fins 12 are partitioned by the plates 10, so that a plurality of flow paths are arranged in the thickness direction. The plurality of flow paths arranged in the thickness direction allow the high-temperature fluid and the low-temperature fluid to circulate such that the flow path through which the high-temperature fluid circulates and the flow path through which the low-temperature fluid circulates alternate. In addition, the flow path is formed such that the fluid flows in one direction in a plane perpendicular to the thickness direction. The flowing direction of the high-temperature fluid and the flowing direction of the low-temperature fluid are opposite directions.

[0017] In such a heat exchanger 1, in a case where the high-temperature fluid and the low-temperature fluid are made to circulate, the high-temperature fluid circulates in a predetermined flowing direction, and the low-temperature fluid circulates in a flowing direction opposite to the flowing direction of the high-temperature fluid. Then, heat is exchanged between the high-temperature fluid and the low-temperature fluid via the plates 10 and the inner fins 12.

[0018] Next, the inner fin 12 will be described with reference to Figs. 2 to 4. As illustrated in Figs. 2 to 4, the inner fin 12 has a plurality of offset fins 15. The plurality of offset fins 15 are arranged side by side along the flowing direction of the fluid. In addition, the plurality of offset fins 15 are provided in a plane perpendicular to the thickness direction such that the positions thereof are mutually offset in the width direction perpendicular to the flowing direction.

[0019] The offset fins 15 are provided across the width direction. The offset fin 15 has a wavy shape in which a part that protrudes toward an upstream side in the flowing direction is set as a top portion 15a, a part that is depressed toward a downstream side in the flowing direction is set as a valley portion 15b, and the top portion 15a and the valley portion 15b are alternately provided along the width direction. One of the offset fins 15 adjacent to each other in the flowing direction and the other of the offset fins 15 adjacent to each other in the flowing direction are arranged line-symmetrically with the width direction as an axis of symmetry, and are arranged such that the positions thereof are mutually offset in the width direction. In addition, in the offset fin 15, in the plan view seen from the height direction perpendicular to the flowing direction and to the width direction, an angle θa at the top portion 15a and the valley portion 15b is in a range from 60 degrees to 160 degrees.

[0020] Here, as illustrated in Fig. 3, the offset fins 15 are arranged in four rows in the flowing direction as one set. The offset fin 15 in the first row that is on the upstream side in the flowing direction and the offset fin 15 in the third row that is on the downstream side in the flowing direction are at the same position in the width direction. The offset fins 15 in the second row is offset to one side in the width direction (to the right in Figs. 3 and 4) with respect to the offset fins 15 in the first and third rows. The offset fins 15 in the fourth row is offset to the other side in the width direction (to the left in Figs. 3 and 4) with respect to the offset fins 15 in the first and third rows.

[0021] Specifically, as illustrated in Fig. 4, the distance between the top portions in the width direction is set as one unit. In this case, the offset fin 15 in the second row is offset by 1/2 unit to one side in the width direction with respect to the offset fins 15 in the first and third rows. In addition, the offset fin 15 in the fourth row is offset by 1/2 unit to the other side in the width direction with respect to the offset fins 15 in the first and third rows. Note that, in the first embodiment, the offset fins 15 in the second and fourth rows are offset by 1/2 unit, but unless restricted by the shape of the offset fins 15, it is preferable to offset the offset fins 15 in the second and fourth rows within a range of 1/4 unit to 1/2 unit.

[0022] Next, the offset fin 15 will be described. The offset fin 15 has a plate joint part 21, a fin part 22, and an inhibiting part 23, and these parts are integrated.

[0023] The plate joint part 21 is a part that is joined to the plate 10. The plate joint part 21 includes a plate joint part 21a joined to one side of the pair of plates 10, and a plate joint part 21b joined to the other side of the pair of plates 10. The plate joint part 21 is formed in a parallelogram plate shape or in a V-shaped plate shape obtained by developing a parallelogram symmetrically in the width direction. The plate joint part 21 constitutes a portion of the top portion 15a and the valley portion 15b of the offset fin 15. In addition, in the plate joint part 21, a surface facing the plate 10 is joined to the plate 10, so that an end portion in the flowing direction, which is exposed on the internal flow path side, is formed as a step 25.

[0024] The fin part 22 is provided across the thickness direction. The fin part 22 is connected to the end portion of the plate joint part 21 in the width direction. The fin part 22 is formed in a plate shape.

[0025] The inhibiting part 23 is provided on the plate joint part 21. The inhibiting part 23 is a part that inhibits the formation of the thermal boundary layer that occurs in the fluid circulating along the inside of the plate joint part 21. Specifically, the inhibiting part 23 is a reception slope 38 that is oblique to the flowing direction and that receives the fluid from the step 25. Since the reception slope 38 is oblique to the flowing direction of the fluid, the fluid flowing along the reception slope 38 becomes a swirling flow that swirls in a circumferential direction with the flowing direction as an axis.

[0026] With reference to Fig. 5, the flow of the fluid circulating in the inner fins 12 of the first embodiment will be described. Fig. 5 illustrates a section taken along a plane perpendicular to the flowing direction, with an upper side of the figure being the upstream side in the flowing direction, and a lower side of the figure being the downstream side in the flowing direction. As the fluid flowing along the reception slope 38 goes from the upstream side to the downstream side in the flowing direction, a flow R1 from the top portion 15a toward the valley portion 15b in the width direction is generated. By applying the flow R1 from the top portion 15a to the valley portion 15b to the fluid, the fluid becomes a swirling flow R2 that swirls in the flowing direction from the top portion 15a to the valley portion 15b. Since the flow velocity of the fluid as the swirling flow R2 increases on the inner side of the plate joint part 21, the formation of the thermal boundary layer occurring on the inner side of the plate joint part 21 is inhibited.

[Second Embodiment]

[0027] Next, a second embodiment will be described with reference to Figs. 6 to 8. Note that, in the second embodiment, in order to avoid duplicate descriptions, portions that are different from those of the first embodiment will be described, and portions having the same configuration as those of the first embodiment will be described with the same reference numerals. Fig. 6 is a perspective view illustrating an offset fin of a heat exchanger according to a second embodiment. Fig. 7 is a perspective view illustrating a protrusion portion of the offset fin. Fig. 8 is a two-sided view of the offset fin.

(Heat Exchanger)

[0028] In a heat exchanger 50 of the second embodiment, a plurality of offset fins 51 in the inner fins 12 are different from the offset fins 15 of the first embodiment.

[0029] The plurality of offset fins 51 are arranged side by side along the flowing direction of the fluid. In addition, the plurality of offset fins 51 are provided in a plane perpendicular to the thickness direction such that the positions thereof are mutually offset in the width direction perpendicular to the flowing direction.

[0030] The offset fins 51 are provided across the width direction. That is, the offset fin 15 is an elongated member of which a longitudinal direction is the width direction. As illustrated in Figs. 6 and 8, the offset fin 51 has a plate joint part 61, a fin part 62, and an inhibiting part 63, and these parts are integrated.

[0031] The plate joint part 61 is a part that is joined to the plate 10. Similar to the plate joint part 21 of the first embodiment, the plate joint part 61 includes a plate joint part 61a joined to one side of the pair of plates 10, and a plate joint part 61b joined to the other side of the pair of plates 10. The plate joint part 61 is formed into a rectangular plate shape. In addition, in the plate joint part 61, a surface facing the plate 10 is joined to the plate 10, so that an end portion in the flowing direction, which is exposed on the internal flow path side, is formed as the step 25.

[0032] The fin part 62 is provided across the thickness direction. The fin part 62 is connected to the end portion of the plate joint part 61 in the width direction. The fin part 62 is formed in a plate shape.

[0033] The inhibiting part 63 is provided on the plate joint part 61. Similar to the first embodiment, the inhibiting part 63 is a part that inhibits the formation of the thermal boundary layer that occurs in the fluid circulating along the inside of the plate joint part 61. Specifically, the inhibiting part 63 is a protrusion portion 65 that protrudes inward from the plate joint part 61. In a case where the plate joint parts 61 are continuous in the offset fins 51 adjacent to each other in the flowing direction, the protrusion portion 65 is provided on the plate joint part 61 on the upstream side in the flowing direction.

[0034] The protrusion portion 65 is formed in a rectangular shape that is long in the flowing direction in plan view seen from the height direction perpendicular to the flowing direction and to the width direction. In addition, the protrusion portion 65 is formed in a triangular shape convex in a protrusion direction in front view seen from the flowing direction. Note that, in the second embodiment, the protrusion portion 65 has a rectangular shape in plan view and a triangular shape in front view, but is not particularly limited to this shape. The protrusion portion 65 may have a polygonal shape or an annular shape such as a circle or an ellipse in plan view, and may have a polygonal shape or an arcuate shape such as a semicircle or an ellipse in front view.

[0035]  The protrusion portion 65 has a first guide slope 65a that slopes from the upstream side toward the downstream side in the flowing direction, and a second guide slope 65b that slopes from one side toward the other side in the width direction. The first guide slope 65a includes an upstream-side guide slope 65a and a downstream-side guide slope 65a. Assuming that an angle formed by the first guide slope 65a and the flowing direction is a first inclination angle Θ1, the first inclination angle Θ1 is in a range of 10 degrees to 60 degrees. Here, the first inclination angle Θ1 on the downstream side may be the same as the first inclination angle Θ1 on the upstream side, or may be larger than the first inclination angle Θ1 on the upstream side with an upper limit of 90 degrees. The second guide slope 65b includes a guide slope 65b on one side in the width direction and a guide slope 65b on the other side in the width direction. Assuming that an angle formed by the second guide slope 65b and the width direction is a second inclination angle θ2, the inclination angles θ2 of the second guide slopes 65b on both sides in the width direction are the same angle.

[0036] In addition, as illustrated in Fig. 8, the protrusion portion 65 is provided at a predetermined position in the flowing direction and the width direction. Specifically, the protrusion portion 65 is disposed at a distance L1, which is equal to or greater than the thickness of the fin part 62, from the end portion of the plate joint part 61 in the flowing direction. In addition, the protrusion portion 65 is disposed at a distance L2, which is equal to or greater than the thickness of the fin part 62, from the fin part 62 in the width direction.

[0037] In the heat exchanger 50 of the second embodiment, some of the fluid circulating in the inner fins 12 in the flowing direction climbs over the step 25 to reach the protrusion portion 65, and flows along the first guide slope 65a. In the plate joint part 61, the fluid flowing along the first guide slope 65a of the protrusion portion 65 and the fluid flowing along the plate joint part 61 where the protrusion portion 65 is not provided have different flow velocities. Therefore, a pressure gradient is generated between the fluids, and the pressure gradient generates a cross-sectional secondary flow of which the cross section is a plane perpendicular to the flowing direction. Since the flow velocity of the fluid increases on the inner side of the plate joint part 21 due to the cross-sectional secondary flow, the formation of the thermal boundary layer occurring on the inner side of the plate joint part 21 is inhibited.

[0038] Note that, in the second embodiment, the protrusion portion 65 has a rectangular shape that is long in the flowing direction, in plan view, but may be disposed as indicated by the dotted line in Fig. 8. That is, the protrusion portion 65 may have a rectangular shape that is long in a direction oblique to the flowing direction, in plan view. Specifically, assuming that an angle formed by the length direction of the protrusion portion 65 and the flowing direction is an inclination angle θ3, the inclination angle θ3 is in a range of 0 degrees to 45 degrees.

[Third Embodiment]

[0039] Next, a third embodiment will be described with reference to Figs. 9 to 12. Note that, in the third embodiment, in order to avoid duplicate descriptions, portions that are different from those of the first and second embodiments will be described, and portions having the same configuration as those of the first and second embodiments will be described with the same reference numerals. Fig. 9 is a perspective view illustrating an offset fin of a heat exchanger according to the third embodiment. Fig. 10 is a plan view of the offset fin. Fig. 11 is a sectional view of the offset fin. Fig. 12 is an explanatory diagram regarding a flow of the fluid.

(Heat Exchanger)

[0040] In a heat exchanger 70 of the third embodiment, a plurality of offset fins 71 in the inner fins 12 are different from the offset fins 15 and 51 of the first and second embodiments.

[0041] The plurality of offset fins 71 are obtained by replacing the inhibiting part 63 of the second embodiment with an inhibiting part 83. Therefore, the inhibiting part 83 of the offset fin 71 will be explained, and the other parts, that is, a plate joint part 81 and a fin part 82 of the offset fin 71, are the same as the plate joint part 61 and the fin part 62 of the second embodiment. Therefore, the description will be omitted.

[0042] The inhibiting part 83 is provided on the plate joint part 81. Similar to the first embodiment, the inhibiting part 83 is a part that inhibits the formation of the thermal boundary layer that occurs in the fluid circulating along the inside of the plate joint part 81. Specifically, the inhibiting part 83 is a hole 85 recessed from the plate joint part 81 toward the plate 10. In a case where the plate joint parts 81 are continuous in the offset fins 71 adjacent to each other in the flowing direction, the hole 85 is provided on the plate joint part 81 on the downstream side in the flowing direction. The hole 85 is a through-hole formed through the plate joint part 81. Note that, in the third embodiment, the hole 85 is a through-hole, but may be a hole with a bottom. At least one or more holes 85 are provided in the inner fins 12 in the flowing direction and the width direction.

[0043] The hole 85 is formed in a rectangular shape in plan view seen from the height direction perpendicular to the flowing direction and to the width direction. Note that, in the third embodiment, the hole 85 has a rectangular shape in plan view, but is not particularly limited to this shape. In plan view, the hole 85 may have a polygonal shape, or may have an annular shape such as a circle or an ellipse. In plan view, the longest length L5 of the hole 85 is equal to or greater than twice the thickness of the fin part 82 and equal to or less than eight times the thickness of the fin part 82.

[0044] In addition, as illustrated in Fig. 10, the hole 85 is provided at a predetermined position in the flowing direction and the width direction. Specifically, the hole 85 is disposed at a distance L3, which is equal to or greater than the thickness of the fin part 82, from the end portion of the plate joint part 81 in the flowing direction. In addition, the hole 85 is disposed at a distance L4, which is equal to or greater than the thickness of the fin part 82, from the fin part 82 in the width direction.

[0045] Next, the plate joint part 81 will be described with reference to Figs. 11 and 12. The plate joint part 81 has a downstream-side slope 81a formed at the end portion on the downstream side in the flowing direction. The downstream-side slope 81a is formed at a part on the downstream side of the plate joint part 81 where no other plate joint part 81 is adjacent thereto on the downstream side in the flowing direction, that is, at a part where a step 88 is formed (refer to the related art of Fig. 12) . Assuming that an angle formed by the downstream-side slope 81a and the flowing direction is a downstream-side inclination angle θ4, the downstream-side inclination angle θ4 is in a range of 7 degrees to 45 degrees.

[0046] As illustrated in Fig. 12, in the related art, in a case where the downstream-side slope 81a is not provided on the plate joint part 81, the end portion of the plate joint part 81 becomes the step 88. Therefore, the fluid circulating through the inner surface of the plate joint part 81 passes through the step 88, thereby forming a separation region due to a separation flow R3. On the other hand, in the third embodiment, in a case where the downstream-side slope 81a is provided on the plate joint part 81, the fluid circulating through the inner surface of the plate joint part 81 flows along the downstream-side slope 81a, thereby suppressing the formation of the separation flow R3.

[0047] In the heat exchanger 70 of the third embodiment, some of the fluid circulating in the inner fins 12 in the flowing direction climbs over the downstream-side slope 81a to reach the hole 85. The fluid flowing along the plate joint part 81 is separated at the hole 85, thereby initializing the formation of the thermal boundary layer occurring on the inner side of the plate joint part 81.

[0048] As described above, the heat exchangers 1, 50, and 70 described in the embodiments described above can be understood as follows, for example.

[0049] A heat exchanger 1 according to a first aspect includes a pair of plates 10 that face each other; and an inner fin 12 which is provided between the pair of plates 10 and in which a fluid circulates, in which the inner fin 12 has a plurality of offset fins 15 which are arranged side by side in a flowing direction of the fluid and are provided such that positions thereof are mutually offset in a width direction perpendicular to the flowing direction, and the offset fin 15 includes a plate joint part 21 which is joined to the plate 10 and has a step 25 formed in the flowing direction, a fin part 22 which is provided along an opposing direction of the pair of plates 10 and is connected to the plate joint part 21, and a reception slope 38 which is provided to the plate joint part 21, obliquely to the flowing direction, and which receives the fluid from the step 25.

[0050] According to this configuration, the reception slope 38 can give the swirling flow R2 to the fluid. Therefore, since the flow velocity increases on the inner side of the plate joint part 21 due to the swirling flow R2, the formation of the thermal boundary layer occurring on the inner side of the plate joint part 21 can be appropriately inhibited. Therefore, since a decrease in heat transfer performance via the plate 10 can be suppressed by reducing the thickness of the thermal boundary layer, a decrease in heat exchange performance of the heat exchanger 1 can be suppressed.

[0051] In a second aspect, the offset fin 15 has a wavy shape in which a part on an upstream side in the flowing direction is set as a top portion 15a, a part on a downstream side in the flowing direction is set as a valley portion 15b, and the top portion 15a and the valley portion 15b are alternately provided along the width direction, and the one of the offset fins 15 adjacent to each other in the flowing direction and the other of the offset fins 15 adjacent to each other in the flowing direction are arranged line-symmetrically with the width direction as an axis of symmetry, and are arranged such that positions thereof are mutually offset in the width direction.

[0052] According to this configuration, since the offset fins 15 can be arranged line-symmetrically and offset, only one type of offset fins 15 can be used for the inner fins 12, and the manufacturing cost can be reduced.

[0053] In a third aspect, the offset fins 15 arranged in four rows in the flowing direction are set as one set, the offset fin 15 in a first row and the offset fin 15 in a third row are at the same position in the width direction, the offset fin 15 in a second row is offset to one side in the width direction with respect to the offset fins 15 in the first and third rows, and the offset fin 15 in a fourth row is offset to the other side in the width direction with respect to the offset fins 15 in the first and third rows.

[0054] According to this configuration, the offset fins 15 can be appropriately arranged to inhibit the formation of the thermal boundary layer. In addition, by arranging one set of offset fins 15 in the flowing direction, the inner fins 12 can be easily configured.

[0055] A heat exchanger 50 according to a fourth aspect includes a pair of plates 10 that face each other; and an inner fin 12 which is provided between the pair of plates 10 and in which a fluid circulates, in which the inner fin 12 has a plurality of offset fins 51 which are arranged side by side in a flowing direction of the fluid and are provided such that positions thereof are mutually offset in a width direction perpendicular to the flowing direction, and the offset fin 51 includes a plate joint part 61 which is joined to the plate 10, a fin part 62 which is provided along an opposing direction of the pair of plates 10 and is connected to the plate joint part 61, and a protrusion portion 65 which is provided on the plate joint part 61 and protrudes inward from the plate joint part 61.

[0056] According to this configuration, the protrusion portion 65 can give a cross-sectional secondary flow to the fluid. Therefore, since the flow velocity increases on the inner side of the plate joint part 21 due to the cross-sectional secondary flow, the formation of the thermal boundary layer occurring on the inner side of the plate joint part 21 can be appropriately inhibited. Therefore, since a decrease in heat transfer performance via the plate 10 can be suppressed by reducing the thickness of the thermal boundary layer, a decrease in heat exchange performance of the heat exchanger 50 can be suppressed.

[0057] In a fifth aspect, in a case where the plate joint parts 61 are continuous in the offset fins 51 adjacent to each other in the flowing direction, the protrusion portion 65 is provided on the plate joint part 61 on the upstream side in the flowing direction.

[0058] According to this configuration, since the protrusion portion 65 can give a cross-sectional secondary flow to the upstream side in the flowing direction, it is possible to appropriately inhibit the formation of the thermal boundary layer on the downstream side.

[0059] In a sixth aspect, the protrusion portion 65 has at least one guide slope 65a or 65b among a guide slope 65a that slopes from the upstream side toward the downstream side in the flowing direction, and a guide slope 65b that slopes from one side toward the other side in the width direction.

[0060] According to this configuration, by causing the fluid to circulate along the guide slopes 65a and 65b, a cross-sectional secondary flow can be easily given to the fluid.

[0061] In a seventh aspect, the protrusion portion 65 has an elongated shape in a direction oblique to the flowing direction.

[0062] According to this configuration, by causing the fluid to circulate along the length direction of the protrusion portion 65, a cross-sectional secondary flow can be easily given to the fluid.

[0063]  In an eighth aspect, the protrusion portion 65 is disposed at a distance L1, which is equal to or greater than a thickness of the fin part 62, from an end portion of the plate joint part 61 in the flowing direction, and the protrusion portion 65 is disposed at a distance L2, which is equal to or greater than the thickness of the fin part 62, from the fin part 62 in the width direction.

[0064] According to this configuration, the protrusion portion 65 can be arranged in an appropriate manner to give a cross-sectional secondary flow to the fluid.

[0065] A heat exchanger 70 according to a ninth aspect includes a pair of plates 10 that face each other; and an inner fin 12 which is provided between the pair of plates 10 and in which a fluid circulates, in which the inner fin 12 has a plurality of offset fins 71 which are arranged side by side in a flowing direction of the fluid and are provided such that positions thereof are mutually offset in a width direction perpendicular to the flowing direction, and the offset fin 71 includes a plate joint part 81 which is joined to the plate 10, a fin part 82 which is provided along an opposing direction of the pair of plates 10 and is connected to the plate joint part 81, and a hole 85 that is provided to the plate joint part 81 and is recessed from the plate joint part 81 toward the plate 10.

[0066] According to this configuration, the hole 85 can separate the flow of the fluid. Therefore, since the formation of the thermal boundary layer can be initialized by separating the flow of the fluid, the formation of the thermal boundary layer can be appropriately inhibited. Therefore, since a decrease in heat transfer performance via the plate 10 can be suppressed by reducing the thickness of the thermal boundary layer, a decrease in heat exchange performance of the heat exchanger 70 can be suppressed.

[0067] In a tenth aspect, in a case where the plate joint parts 81 are continuous in the offset fins 71 adjacent to each other in the flowing direction, the hole 85 is provided to the plate joint part 81 on the downstream side in the flowing direction.

[0068] According to this configuration, since the formation of the thermal boundary layer can be initialized by the hole 85, on the downstream side where the thermal boundary layer becomes thicker, the formation of the thermal boundary layer on the downstream side can be appropriately inhibited.

[0069] In an eleventh aspect, the hole 85 has a longest length in a plane of the plate 10 of equal to or greater than twice a thickness of the fin part 82 and equal to or less than eight times the thickness of the fin part 82.

[0070] According to this configuration, the size of the hole 85 can be set to an appropriate size that initializes the formation of the thermal boundary layer.

[0071] In a twelfth aspect, the hole 85 is disposed at a distance L3, which is equal to or greater than a thickness of the fin part 82, from an end portion of the plate joint part 81 in the flowing direction, and the hole 85 is disposed at a distance L4, which is equal to or greater than the thickness of the fin part 82, from the fin part 82 in the width direction.

[0072] According to this configuration, the hole 85 can be disposed in an appropriate manner to initialize the formation of the thermal boundary layer.

[0073] In a thirteenth aspect, the plate joint part 81 has a downstream-side slope 81a that is formed at an end portion on the downstream side in the flowing direction and slopes toward the plate 10 toward the downstream side in the flowing direction.

[0074] According to this configuration, the fluid flows along the downstream-side slope 81a, and thus, the formation of the separation flow R3 is suppressed. Therefore, since the formation of the separation flow R3 is suppressed, the heat transfer area of the fluid on the downstream side of the plate joint part 81 can be increased, and thus, the heat transfer performance can be improved. In addition, pressure loss can be reduced by suppressing the formation of the separation flow R3.

Reference Signs List

[0075] 

1:

heat exchanger

10:

plate

12:

inner fin

15:

offset fin

21:

plate joint part

22:

fin part

23:

inhibiting part

25:

step

38:

reception slope

50:

heat exchanger (second embodiment)

51:

offset fin

61:

plate joint part

62:

fin part

63:

inhibiting part

65:

protrusion portion

70:

heat exchanger (third embodiment)

71:

offset fin

81:

plate joint part

82:

fin part

83:

inhibiting part

85:

hole

88:

step

Claims

1. A heat exchanger comprising:

a pair of plates that face each other; and

an inner fin which is provided between the pair of plates and in which a fluid circulates,

wherein the inner fin has a plurality of offset fins which are arranged side by side in a flowing direction of the fluid and are provided such that positions thereof are mutually offset in a width direction perpendicular to the flowing direction, and

the offset fin includes

a plate joint part which is joined to the plate and has a step formed in the flowing direction,

a fin part which is provided along an opposing direction of the pair of plates and is connected to the plate joint part, and

a reception slope which is provided on the plate joint part, obliquely to the flowing direction, and which receives the fluid from the step.

2. The heat exchanger according to claim 1,

wherein the offset fin has a wavy shape in which a part on an upstream side in the flowing direction is set as a top portion, a part on a downstream side in the flowing direction is set as a valley portion, and the top portion and the valley portion are alternately provided along the width direction, and

one of the offset fins adjacent to each other in the flowing direction and the other of offset fins adjacent to each other in the flowing direction are arranged line-symmetrically with the width direction as an axis of symmetry, and are arranged such that positions thereof are mutually offset in the width direction.

3. The heat exchanger according to claim 1 or 2,

wherein the offset fins arranged in four rows in the flowing direction are set as one set,

the offset fin in a first row and the offset fin in a third row are at the same position in the width direction,

the offset fin in a second row is offset to one side in the width direction with respect to the offset fins in the first and third rows, and

the offset fin in a fourth row is offset to the other side in the width direction with respect to the offset fins in the first and third rows.

4. A heat exchanger comprising:

a pair of plates that face each other; and

an inner fin which is provided between the pair of plates and in which a fluid circulates,

wherein the inner fin has a plurality of offset fins which are arranged side by side in a flowing direction of the fluid and are provided such that positions thereof are mutually offset in a width direction perpendicular to the flowing direction, and

the offset fin includes

a plate joint part which is joined to the plate,

a fin part which is provided along an opposing direction of the pair of plates and is connected to the plate joint part, and

a protrusion portion which is provided on the plate joint part and protrudes inward from the plate joint part.

5. The heat exchanger according to claim 4,
wherein, in a case where the plate joint parts are continuous in the offset fins adjacent to each other in the flowing direction, the protrusion portion is provided on the plate joint part on an upstream side in the flowing direction.

6. The heat exchanger according to claim 4 or 5,
wherein the protrusion portion has at least one guide slope among a guide slope that slopes from an upstream side toward a downstream side in the flowing direction, and a guide slope that slopes from one side toward the other side in the width direction.

7. The heat exchanger according to claim 4 or 5,
wherein the protrusion portion has an elongated shape in a direction oblique to the flowing direction.

8. The heat exchanger according to any one of claims 4 to 7,

wherein the protrusion portion is disposed at a distance, which is equal to or greater than a thickness of the fin part, from an end portion of the plate joint part in the flowing direction, and

the protrusion portion is disposed at a distance, which is equal to or greater than the thickness of the fin part, from the fin part in the width direction.

9. A heat exchanger comprising:

a pair of plates that face each other; and

an inner fin which is provided between the pair of plates and in which a fluid circulates,

wherein the inner fin has a plurality of offset fins which are arranged side by side in a flowing direction of the fluid and are provided such that positions thereof are mutually offset in a width direction perpendicular to the flowing direction, and

the offset fin includes

a plate joint part which is joined to the plate,

a fin part which is provided along an opposing direction of the pair of plates and is connected to the plate joint part, and

a hole that is provided to the plate joint part and is recessed from the plate joint part toward the plate.

10. The heat exchanger according to claim 9,
wherein, in a case where the plate joint parts are continuous in the offset fins adjacent to each other in the flowing direction, the hole is provided to the plate joint part on a downstream side in the flowing direction.

11. The heat exchanger according to claim 9 or 10,
wherein the hole has a longest length in a plane of the plate of equal to or greater than twice a thickness of the fin part and equal to or less than eight times the thickness of the fin part.

12. The heat exchanger according to any one of claims 9 to 11,

wherein the hole is disposed at a distance, which is equal to or greater than a thickness of the fin part, from an end portion of the plate joint part in the flowing direction, and

the hole is disposed at a distance, which is equal to or greater than the thickness of the fin part, from the fin part in the width direction.

13. The heat exchanger according to any one of claims 1 to 12,
wherein the plate joint part has a downstream-side slope that is formed at an end portion on a downstream side in the flowing direction and slopes toward the plate toward the downstream side in the flowing direction.

Drawing