Heat exchanger

Abstract

To provide a heat exchanger that restrains unevenness of a flow of a refrigerant in a flow passage.SOLUTION: In a heat exchanger, a plurality of metal plates are stacked. At least one of the plurality of metal plates comprises an inflow port, an outflow port, a partition wall, and a plurality of protrusions protruding from the partition wall. A flow passage part is formed on the partition wall by the plurality of protrusions. The flow passage part comprises a first flow passage part, a second flow passage part, and a third flow passage part between the inflow port and the outflow port. The first flow passage part, the second flow passage part, and the third flow passage part are arranged in this order from the inflow port toward the outflow port. Flow passage resistance of the second flow passage part is larger than flow passage resistance of each of the first flow passage part and the third flow passage part.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a stacked heat exchanger. [Background technology]

[0002] There is a heat exchanger in which a flow path is formed on each of one side and the other side of a plate-shaped metal plate by providing a plurality of columnar protrusions on each of the sides of the metal plate (for example, see Patent Document 1). In this heat exchanger, the flow path formed on one side of the metal plate functions as a high-temperature flow path, and the flow path formed on the other side of the metal plate functions as a low-temperature flow path. In this heat exchanger, the width of the inlet and the width of the outlet are formed to be the same as the width of the flow path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2018-096581 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above heat exchanger, the multiple protrusions on one side and the other side of the metal plate are arranged at uniform intervals. In such a case, even if the width of the inlet is the same as the width of the flow path, the refrigerant is likely to become unevenly distributed in the flow path, and a dead water area where the refrigerant does not sufficiently flow through the flow path may be formed.

[0005] In view of the above circumstances, an object of the present invention is to provide a heat exchanger in which the bias of the flow of the refrigerant in the flow passage is suppressed. [Means for solving the problem]

[0006] In order to achieve the above object, a heat exchanger according to one embodiment of the present invention is a heat exchanger in which a plurality of metal plates are stacked. At least one of the plurality of metal plates has an inlet, an outlet, a partition wall, and a plurality of protrusions protruding from the partition wall. A flow path portion is formed on the partition wall by the plurality of protrusions. The flow path portion has a first flow path portion, a second flow path portion, and a third flow path portion between the inlet and the outlet. The first flow path portion, the second flow path portion, and the third flow path portion are arranged in this order from the inlet to the outlet. The second flow path portion has a flow path resistance greater than the flow path resistances of the first flow path portion and the third flow path portion.

[0007] With such a heat exchanger, unevenness in the flow of the refrigerant within the flow passages is suppressed.

[0008] In the heat exchanger, a flow path cross-sectional area of ​​the second flow path portion may be smaller than each of the flow path cross-sectional areas of the first flow path portion and the third flow path portion. heat exchanger.

[0009] With such a heat exchanger, the bias of the refrigerant flow within the flow passage can be further suppressed.

[0010] In the heat exchanger, an area per unit area occupied by the protrusions in the second flow path portion may be larger than an area per unit area occupied by the protrusions in the first flow path portion and the third flow path portion.

[0011] With such a heat exchanger, the bias of the refrigerant flow within the flow passage can be further suppressed.

[0012] In the heat exchanger, the second flow path portion may be disposed closer to the inlet than the outlet.

[0013] With such a heat exchanger, the bias of the refrigerant flow within the flow passage can be further suppressed.

[0014] In the heat exchanger, the second flow path portion may be disposed closer to the outlet than the inlet.

[0015] With such a heat exchanger, the bias of the refrigerant flow within the flow passage can be further suppressed. Effect of the Invention

[0016] As described above, according to the present invention, a heat exchanger is provided in which the bias of the refrigerant flow in the flow passage is suppressed. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 is a schematic perspective view showing the heat exchanger of the present embodiment. [Diagram 2] FIG. 2 is a schematic perspective view of a heat exchanger with a part thereof removed. [Diagram 3] FIG. 2 is a schematic perspective view of a heat exchanger with a part thereof removed. [Figure 4] FIG. 1A is a schematic plan view of at least one metal plate 22 among the multiple metal plates 22 forming the laminate 20. FIG. 1B is a schematic cross-sectional view taken along line B1-B2 in FIG. 1A. [Diagram 5] FIG. (a) is a schematic plan view of at least one metal plate 22 among the multiple metal plates 21 forming the laminate 20. FIG. (b) is a schematic cross-sectional view taken along line A11-A12 in FIG. (a). FIG. (b) is a schematic cross-sectional view taken along line A21-A22 in FIG. (a). FIG. (c) is a schematic cross-sectional view taken along line A31-A32 in FIG. (a). [Figure 6] 11A and 11B are schematic plan views showing the function of a metal plate according to a reference example. [Figure 7] FIG. 11 is a schematic plan view illustrating an example of the operation of the present embodiment. [Figure 8] FIG. 1A is a schematic plan view according to a first modified example of the present embodiment, and FIG. 1B is a schematic plan view according to a second modified example of the present embodiment. [Figure 9]FIG. 1A is a schematic plan view according to a third modified example of the present embodiment, and FIG. 1B is a schematic plan view according to a fourth modified example of the present embodiment. [Figure 10] FIG. 10 is a schematic plan view according to the fifth modified example of the present embodiment. [Figure 11] FIG. 11 is a schematic plan view according to the sixth modified example of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. XYZ axis coordinates may be introduced in each drawing. In addition, the same reference numerals may be used to designate the same components or components having the same functions, and after describing the components, the description may be omitted as appropriate.

[0019] (heat exchanger) FIG. 1 is a schematic perspective view showing a heat exchanger of the present embodiment.

[0020] The heat exchanger 1 is a heat exchanger in which a plurality of metal plates are stacked. The heat exchanger 1 has a main surface (front surface) 1u, a main surface (back surface) 1d opposite to the main surface 1u, and a side surface 1w connected to the main surface 1u and the main surface 1d. The heat exchanger 1 is applied to, for example, a stacked type microchannel heat exchanger. The heat exchanger 1 includes a heat exchanger body 2. The heat exchanger body 2 is provided with an inlet pipe 5, an outlet pipe 6, an outlet pipe 7, and an inlet pipe 8. A straight line connecting the inlet pipe 5 and the outlet pipe 6 intersects with a straight line connecting the inlet pipe 8 and the outlet pipe 7. In this embodiment, the stacking direction of the plurality of metal plates in the heat exchanger 1 is the Z-axis direction, the direction in which the inlet pipe 5 is viewed from the inlet pipe 8 is the X-axis direction, and the direction in which the outlet pipe 6 is viewed from the inlet pipe 8 is the Y-axis direction.

[0021] The heat exchanger body 2 has a laminated body 20, a metal plate (top plate) 3, and a metal plate (bottom plate) 4. The laminated body 20 is sandwiched between the metal plate 3 and the metal plate 4 in the lamination direction of the heat exchanger 1 (lamination direction of the multiple metal plates). The side surface 1w of the heat exchanger 1 also serves as the side surface of the heat exchanger body 2 and the laminated body 20. The laminated body 20 has a plurality of metal plates (first heat transfer plates) 21 and a plurality of metal plates (second heat transfer plates) 22. Each of the metal plate 3, the multiple metal plates 21, the multiple metal plates 22, and the metal plate 4 is formed in a plate shape. In the laminated body 20, the multiple metal plates 21 and the multiple metal plates 22 are alternately laminated. Each of the metal plates 3 and the metal plates 4 is an outer shell plate in the laminated body 20, and does not have a flow path formed therein.

[0022] Each of the metal plate 4, the plurality of metal plates 21, the plurality of metal plates 22, and the metal plate 3 is integrally formed by, for example, diffusion bonding, brazing, or the like. For example, in the example of Fig. 1, the metal plate 21 is stacked directly on the metal plate 4, the metal plate 22 is stacked on top of that, and the metal plates 21 and 22 are alternately stacked on top of that, with the metal plate 22 being the topmost layer in the heat exchanger body 2, and the metal plate 3 being stacked on this metal plate 22. Each of the metal plate 3 and the metal plate 4 is not limited to a single metal plate, and may be a metal plate in which a plurality of metal plates are stacked and integrated with the laminate 20 by diffusion bonding, or a metal plate in which a plurality of metal plates are joined in the stacking direction by brazing or the like.

[0023] When the heat exchanger 1 functions as an evaporator, for example, a low-temperature fluid (e.g., a liquid refrigerant or a two-phase gas-liquid refrigerant that undergoes a phase change during heat exchange) flows into the heat exchanger body 2 through the inflow pipe 8. Also, a high-temperature fluid (e.g., water or hot water that does not undergo a phase change during heat exchange, or a liquid refrigerant or a two-phase gas-liquid refrigerant that undergoes a phase change during heat exchange) flows into the heat exchanger body 2 through the inflow pipe 5. The low-temperature fluid that exchanges heat with the high-temperature fluid by flowing through the flow path in the heat exchanger body 2 is heated and its dryness increases, and it flows out of the heat exchanger body 2 from the heat exchanger body 2 through the outflow pipe 7. The high-temperature fluid that has exchanged heat with the low-temperature fluid in the heat exchanger body 2 becomes lower in temperature and flows out of the heat exchanger body 2 from the heat exchanger body 2 through the outflow pipe 6.

[0024] 1, solid lines are drawn to indicate the boundaries between the metal plates stacked in the stacking direction, but the boundaries may disappear after joining, making the solid lines invisible. Also, the stack 20 may be formed by a pair of metal plates 21 and 22.

[0025] Fig. 2 is a schematic perspective view of a heat exchanger with a part removed. For example, Fig. 2 shows a state in which a metal plate 4 (bottom plate) and a metal plate 3 (top plate) have been removed from a heat exchanger 1. Fig. 2 also shows an inlet pipe 5, an outlet pipe 6, an outlet pipe 7, and an inlet pipe 8 having been removed from a heat exchanger body 2.

[0026] The laminate 20 is formed with an inflow space 15, an outflow space 16, an outflow space 17, and an inflow space 18. The spaces 15, 16, 17, and 18 penetrate the laminate 20 in the stacking direction. The spaces 15, 16, 17, and 18 are closed by the metal plates 3 and 4 in the stacking direction of the laminate 20.

[0027] An opening 150 communicating with space 15, an opening 160 communicating with space 16, an opening 170 communicating with space 17, and an opening 180 communicating with space 18 are formed on a side surface 1w of laminate 20. Opening 150 is formed on side surface 1w in the vicinity of space 15. Opening 160 is formed on side surface 1w in the vicinity of space 16. Opening 170 is formed on side surface 1w in the vicinity of space 17. Opening 180 is formed on side surface 1w in the vicinity of space 18.

[0028] The inflow pipe 5 shown in FIG. 1 is inserted into the opening 150 and communicates with the space 15. The inflow pipe 5 is joined to the opening 150 by, for example, brazing. The outflow pipe 6 is inserted into the opening 160 and communicates with the space 16. The outflow pipe 6 is joined to the opening 160 by, for example, brazing. The outflow pipe 7 is inserted into the opening 170 and communicates with the space 17. The outflow pipe 7 is joined to the opening 170 by, for example, brazing. The inflow pipe 8 is inserted into the opening 180 and communicates with the space 18. The inflow pipe 8 is joined to the opening 180 by, for example, brazing.

[0029] For example, a recess 220 recessed toward the principal surface 1d is formed on the principal surface 1u side of the metal plate 22, and a flow path (described later) is formed in a region 221 indicated by dots in the recess 220. The flow path (or the recess 220) of the metal plate 22 communicates with the space portion 15 and the space portion 16.

[0030] Fig. 3 is a schematic perspective view of the heat exchanger with a part thereof removed, showing a state in which the uppermost metal plate 22 on the main surface 1u side has been removed from the state shown in Fig. 2.

[0031] For example, a recess 210 recessed toward the principal surface 1d is formed on the principal surface 1u side of the metal plate 21, and a flow path (described later) is formed in a region 211 indicated by dots in the recess 210. The flow path (or the recess 210) of the metal plate 21 communicates with the space portion 17 and the space portion 18.

[0032] The metal plate 21 and the metal plate 22 which form the laminate 20 will be described, starting with the metal plate 22.

[0033] Fig. 4(a) is a schematic plan view of at least one metal plate 22 among the multiple metal plates 22 forming the laminate 20. Fig. 4(b) is a schematic cross-sectional view taken along line B1-B2 in Fig. 4(a).

[0034] The metal plate 22 has a through hole 252 serving as an inlet, a through hole 262 serving as an outlet, a through hole 272, a through hole 282, a partition wall (bottom) 222, an outer periphery (side wall) 223 surrounding the partition wall 222, and a plurality of columnar protrusions 224 provided on the partition wall 222 and protruding from the partition wall 222. The through hole 252, the through hole 262, the through hole 272, and the through hole 282 penetrate the metal plate 22 in the thickness direction. The planar shape of each of the plurality of protrusions 224 is, for example, a circle. The plurality of protrusions 224 are arranged, for example, in a staggered pattern. A step is formed by the partition wall 222 and the outer periphery 223, and a recess 220 is formed in the metal plate 22. The partition wall 222 is the bottom of the recess 220.

[0035] Furthermore, a plurality of protrusions 224 are formed on the partition wall 222, thereby forming a flow path portion 225 on the partition wall 222. The through hole 252 and the through hole 262 communicate with the flow path portion 225 on the partition wall 222. The through hole 272 and the through hole 282 do not communicate with the flow path portion 225 on the partition wall 222. For example, when the heat exchanger 1 functions as an evaporator, the high-temperature fluid flows in from the through hole 252, passes through the flow path portion 225 on the partition wall 222, and flows out to the through hole 262. Note that, for the metal plate 22, an example in which the protrusions 224 are not provided on the partition wall 222 is also included in this embodiment.

[0036] Next, the metal plate 21 will be described.

[0037] Fig. 5(a) is a schematic plan view of at least one metal plate 22 of the multiple metal plates 21 forming the laminate 20. Fig. 5(b) is a schematic cross-sectional view taken along line A11-A12 in Fig. 5(a). Fig. 5(b) is a schematic cross-sectional view taken along line A21-A22 in Fig. 5(a). Fig. 5(c) is a schematic cross-sectional view taken along line A31-A32 in Fig. 5(a).

[0038] The metal plate 21 has a through hole 251, a through hole 261, a through hole 271 serving as an outlet, a through hole 281 serving as an inlet, a partition wall (bottom) 212, an outer periphery (side wall) 213 surrounding the partition wall 212, and a plurality of columnar protrusions 214 provided on the partition wall 212 and protruding from the partition wall 212. The plurality of protrusions 214 include a plurality of protrusions 2141 (first protrusions), a plurality of protrusions 2142 (second protrusions), and a plurality of protrusions 2143 (third protrusions). The through hole 251, the through hole 261, the through hole 271, and the through hole 281 penetrate the metal plate 21 in the thickness direction. The planar shape of each of the plurality of protrusions 214 is, for example, a circle. A step is formed by the partition wall 212 and the outer periphery 213, and a recess 210 is formed in the metal plate 21. The partition wall 212 is the bottom of the recess 210 .

[0039] Furthermore, a flow path portion 215 is formed on the partition wall 212 by forming the multiple protrusions 214 on the partition wall 212. The through hole 271 and the through hole 281 communicate with the flow path portion 215 on the partition wall 212. The through hole 251 and the through hole 261 do not communicate with the flow path portion 215 on the partition wall 212. For example, when the heat exchanger 1 is made to function as an evaporator, the low-temperature fluid flows in from the through hole 281, passes through the flow path portion 215 on the partition wall 212, and flows out to the through hole 271.

[0040] The flow path section 215 has a first flow path section 2151, a second flow path section 2152, and a third flow path section 2153 between the through hole (inlet) 281 and the through hole (outlet) 271. In the flow path section 215, the first flow path section 2151, the second flow path section 2152, and the third flow path section 2153 are arranged in this order from the through hole 281 toward the through hole 271. Between the through hole 281 and the through hole 271, the second flow path section 2152 is sandwiched between the first flow path section 215 and the third flow path section 2153.

[0041] In the first flow path section 2151, the multiple protrusions 2141 are arranged, for example, in a staggered pattern. In the second flow path section 2152, the multiple protrusions 2142 are arranged, for example, linearly in a direction (Y-axis direction) perpendicular to the direction from the first flow path section 215 to the third flow path section 2153. In the third flow path section 2153, the multiple protrusions 2143 are arranged, for example, in a staggered pattern.

[0042] In the metal plate 21, the area of ​​the protrusions 2142 when the metal plate 21 is viewed from above is smaller than the area of ​​the protrusions 2141 and the area of ​​the protrusions 2143. Furthermore, in the second flow path portion 2152, the protrusions 2142 are arranged more densely than the protrusions 2141 included in the first flow path portion 2151 and the protrusions 2143 included in the third flow path portion 2153.

[0043] That is, in the second flow path section 2152, the area occupied by the protrusion 2142 per unit area of ​​the second flow path section 2152 (the area occupied by the multiple protrusions 2142 included in the second flow path section 2152 per unit area of ​​the metal plate 21) is larger than the area occupied by the protrusion 2141 per unit area of ​​the first flow path section 2151 (the area occupied by the multiple protrusions 2141 included in the first flow path section 2151 per unit area of ​​the metal plate 21) in the first flow path section, and is larger than the area occupied by the protrusion 2143 per unit area of ​​the third flow path section 2153 (the area occupied by the multiple protrusions 2143 included in the third flow path section 2153 per unit area of ​​the metal plate 21).

[0044] As a result, in the metal plate 21, the flow path cross-sectional area of ​​the second flow path section 2152 (cross-sectional area perpendicular to the direction in which the fluid flows in the flow path of the second flow path section 2152) is smaller than the flow path cross-sectional area of ​​the first flow path section 2151 (cross-sectional area perpendicular to the direction in which the fluid flows in the flow path of the second flow path section 2151) and the flow path cross-sectional area of ​​the third flow path section 2153 (cross-sectional area perpendicular to the direction in which the fluid flows in the flow path of the third flow path section 2153). That is, the flow path resistance of the second flow path section 2152 is larger than the flow path resistance of the first flow path section 2151 and the flow path resistance of the third flow path section 2153. That is, in a flow path section having a large number of protrusions or a large cross-sectional area of ​​the protrusions, the area of ​​the protrusions per unit area becomes large, and the flow path resistance becomes large. Note that the flow path resistance means a force that hinders the flow of the fluid received from the flow path when the fluid flows through the flow path of the heat exchanger or the like.

[0045] In the laminate 20, when a plurality of metal plates 21 and a plurality of metal plates 22 are alternately laminated, the through holes 251 and 252 are connected in the stacking direction to form the space portion 15. The through holes 261 and 262 are connected in the stacking direction to form the space portion 16. The through holes 271 and 272 are connected in the stacking direction to form the space portion 17. The through holes 281 and 282 are connected in the stacking direction to form the space portion 18.

[0046] (action) The operation of the heat exchanger 1 when used as an evaporator will be described. In this case, a low-temperature fluid flows into the flow path 215 of the metal plate 21 from the through-hole (inlet) 281. This low-temperature fluid is a liquid refrigerant or a gas-liquid two-phase refrigerant (a refrigerant having a higher ratio of liquid components than gas components) with a low dryness, and exchanges heat with a high-temperature fluid flowing through the flow path 225 of the metal plate 22, increasing the dryness, and flows out of the metal plate 21 through the through-hole (outlet) 271.

[0047] Here, when liquid refrigerant or two-phase gas-liquid refrigerant flows through the flow path of the metal plate, the liquid refrigerant or two-phase gas-liquid refrigerant has a larger inertia than the gas refrigerant, so it is difficult for it to flow evenly through the flow path, and a phenomenon in which the liquid refrigerant or two-phase gas-liquid refrigerant does not spread throughout the flow path (the formation of a dead water area) may occur. In addition, the gas refrigerant has a smaller inertia than the liquid refrigerant or two-phase gas-liquid refrigerant. For this reason, the gas refrigerant tends to spread within the flow path. In such a case, the gas refrigerant is biased to both sides of the flow path, and the liquid refrigerant or two-phase gas-liquid refrigerant is carried by the gas refrigerant flux and reaches the outlet, making it even more difficult for the liquid refrigerant or two-phase gas-liquid refrigerant to spread within the flow path.

[0048] For example, Fig. 6 is a schematic plan view showing the function of a metal plate according to a reference example. In the metal plate 100 shown in Fig. 6, a plurality of protrusions 2145 having the same planar shape are arranged in a staggered pattern at equal intervals.

[0049] In such a case, the liquid refrigerant or the gas-liquid two-phase refrigerant flowing from the through hole (inlet) 281 is likely to be biased in a direction perpendicular to the refrigerant flow direction while flowing through the flow path of the metal plate 100 toward the through hole (outlet) 271. For example, if a virtual line 101 is drawn from the through hole (inlet) 281 to the through hole (outlet) 271, the liquid refrigerant or the gas-liquid two-phase refrigerant may be biased near the virtual line 101, and the proportion of gas refrigerant may increase as the distance from the virtual line 101 increases. For example, in FIG. 6, the region where the liquid refrigerant is more abundant than the gas refrigerant is indicated as region 100L indicated by dots. Also, the dead water region where the liquid refrigerant does not reach the flow path of the metal plate 100 is indicated as region 100d surrounded by a dashed line.

[0050] That is, when the liquid refrigerant or the gas-liquid two-phase refrigerant flows in from the through hole (inlet) 281 and flows toward the through hole (outlet) 271, the inertia of the liquid refrigerant or the gas-liquid two-phase refrigerant is larger than that of the gas refrigerant. In addition, the speed of the gas refrigerant is high, and the liquid refrigerant is carried by the gas flow of the gas refrigerant, so that the liquid refrigerant moves more linearly. As a result, the liquid refrigerant is less likely to spread in the direction perpendicular to the imaginary line 101. In particular, when the through hole (inlet) 281 and the through hole (outlet) 271 are narrow and disposed near the corner of the recess 210, such a phenomenon becomes prominent. When a dead water area is formed in the flow path, the portion of the heat exchange section 215 that functions as an evaporator for evaporating the liquid refrigerant or the gas-liquid two-phase refrigerant is reduced, and the heat exchange capacity is reduced. Therefore, it is preferable to suppress the occurrence of the dead water area and to distribute the liquid refrigerant or the gas-liquid two-phase refrigerant evenly throughout the flow path.

[0051] The operation of this embodiment will be described below. Fig. 7 is a schematic plan view for explaining an example of the operation of this embodiment. Fig. 7 shows a schematic plan view of a metal plate 21.

[0052] In the metal plate 21, the flow path portion 215 has a first flow path portion 2151, a second flow path portion 2152, and a third flow path portion 2153. The flow path resistance of the second flow path portion 2152 is greater than the flow path resistance of the first flow path portion 2151 and the flow path resistance of the third flow path portion 2153.

[0053] Therefore, the flow of the liquid refrigerant or the two-phase gas-liquid refrigerant that flows in from the through hole 281 is hindered by the second flow path portion 2152, and the region between the through hole 281 and the second flow path portion 2152, i.e., the first flow path portion 2151, approaches a state in which the liquid refrigerant or the two-phase gas-liquid refrigerant is filled. That is, the liquid refrigerant or the two-phase gas-liquid refrigerant is likely to spread in a direction perpendicular to the virtual line 101 in the first flow path portion 2151. Furthermore, after being rectified by the second flow path portion 2152, the liquid refrigerant or the two-phase gas-liquid refrigerant passes through the third flow path portion 2153 while maintaining a state in which it spreads in a direction perpendicular to the virtual line 101, and flows out of the metal plate 21 from the through hole 271 (the region 21L indicated by dots).

[0054] In this manner, when the heat exchanger 1 is used, the area between the through hole 281 and the second flow path portion 2152 becomes easily filled with liquid refrigerant or two-phase gas-liquid refrigerant, and the liquid refrigerant or two-phase gas-liquid refrigerant spreads throughout the entire flow path.

[0055] Furthermore, when the heat exchanger 1 is used, the second flow path portion 2152 straightens the refrigerant flowing in from the inlet 281, eliminating the need for a flow dividing portion (header portion) that divides the refrigerant flowing in from the inlet before the flow path. Therefore, the entire area of ​​the recess 210 functions as a heat exchange portion, making it possible to reduce the size of the heat exchanger. Also, the pressure loss of the low-temperature refrigerant caused by providing a flow dividing portion is suppressed. Also, since the multiple protrusions 2142 are densely arranged in the center portion of the metal plate 21, the strength of the center portion where the dynamic pressure of the fluid in the flow path becomes relatively high is improved, and deformation of the metal plate 21 is suppressed.

[0056] In the metal plate 22, a high-temperature fluid such as water or hot water flows in through the through hole (inlet) 252. The high-temperature fluid that flows in through the through hole 252 is heat-exchanged with the low-temperature fluid flowing in the metal plate 21, and the temperature is reduced, and the high-temperature fluid flows out of the metal plate 22 through the through hole (outlet) 262. In the metal plate 22, the high-temperature fluid that flows through the flow path portion 225 is water or hot water that does not undergo a phase change during heat exchange, or a gas refrigerant that undergoes a phase change during heat exchange. Here, since the heat exchanger 1 functions as an evaporator for low-temperature fluid, when the high-temperature fluid is a refrigerant that undergoes a phase change, the high-temperature fluid flows in as a single-phase gas from the inlet. Therefore, even if the flow path resistance of the flow path portion 225 is uniform as in the flow path portion 225 shown in FIG. 4(a), the liquid refrigerant spreads evenly throughout the flow path portion 225. In addition, an example in which the flow path portion of the metal plate 21 is applied to the flow path portion of the metal plate 22 is also included in this embodiment.

[0057] (Modification) The second flow path portion 2152 of the metal plate 21 is not limited to the structure shown in Fig. 5(a). For example, Fig. 8(a) is a schematic plan view according to Modification 1 of this embodiment, Fig. 8(b) is a schematic plan view according to Modification 2 of this embodiment, Fig. 9(a) is a schematic plan view according to Modification 3 of this embodiment, and Fig. 9(b) is a schematic plan view according to Modification 4 of this embodiment. Fig. 10 is a schematic plan view according to Modification 5 of this embodiment. Fig. 11 is a schematic plan view according to Modification 6 of this embodiment.

[0058] For example, in Modification 1 shown in FIG. 8(a), a plurality of protrusions 2142a having a circular planar shape are linearly arranged in the second flow path section 2152. Here, the area of ​​the protrusions 2142a when the metal plate 21 is viewed from above is larger than the area of ​​the protrusions 2141 and the area of ​​the protrusions 2143. By making the area of ​​the protrusions 2142a larger than the area of ​​the protrusions 2141 and the area of ​​the protrusions 2143, the gap between the adjacent protrusions 2142a is narrowed. As a result, the flow path resistance of the second flow path section 2152 is larger than the flow path resistance of the first flow path section 2151 and the flow path resistance of the third flow path section 2153. Such a structure is also included in this embodiment.

[0059] 8(b), a plurality of protrusions 2142b having a diamond-shaped planar shape may be arranged in the second flow path section 2152, and a plurality of protrusions 2142c having a rectangular planar shape may be arranged in the second flow path section 2152, as in Modification 2 shown in Fig. 9(a). Even with such a structure, the flow path resistance of the second flow path section 2152 becomes larger than the flow path resistance of the first flow path section 2151 and the flow path resistance of the third flow path section 2153.

[0060] 9(b), a plurality of protrusions 2142d having an S-shaped planar shape may be arranged in the second flow path section 2152. By arranging a plurality of S-shaped protrusions 2142d in the second flow path section 2152, the second flow path section 2152 has a high resistance to the low-temperature fluid, and the liquid refrigerant or the liquid refrigerant in the gas-liquid two-phase refrigerant tends to fill the second flow path section 2152 before the second flow path section 2152. Such a structure is also included in this embodiment.

[0061] 10, in the metal plate 21, the second flow path portion 2152 is disposed closer to the through hole (inlet) 281 than the through hole (outlet) 271. This makes the area of ​​the third flow path portion 2153 larger than the area of ​​the first flow path portion 2151. Also, for the low-temperature fluid flowing in from the through hole 281, the distance it flows through the third flow path portion 2153 is longer than the distance it flows through the first flow path portion 2151.

[0062] In addition, in the fifth modification, the second flow path section 2152 having a high flow path resistance is provided near the inlet. Therefore, the second flow path section 2152 functions as a branch section for the low-temperature fluid, and the low-temperature fluid that passes through the second flow path section 2152 and is branched by the second flow path section 2152 flows into the through-hole 271 while being widely diffused in the wide third flow path section 2153. As a result, the low-temperature fluid is distributed evenly throughout the flow path section 215, and the heat exchange capacity of the heat exchanger 1 is improved.

[0063] In addition, in the sixth modification shown in FIG. 11, the second flow path portion 2152 is disposed closer to the through hole (outlet) 271 than the through hole (inlet) 281. In the sixth modification shown in FIG.

[0064] In a metal plate that does not have a second flow path section 2152 with high flow path resistance, as in the reference example shown in Figure 6, there is nothing to obstruct the flow of the low-temperature fluid, so the liquid refrigerant flows straight from the inlet to the outlet.

[0065] In contrast, if the second flow path section 2152 with high flow path resistance is disposed near the outlet, there is something blocking the flow of the liquid refrigerant or two-phase refrigerant on the downstream side of the flow path, so the liquid refrigerant or two-phase refrigerant flows while making a detour before the second flow path section 2152. In other words, if the second flow path section 2152, which is difficult to flow through, is present in the flow path, the liquid refrigerant or two-phase refrigerant tries to first flow into the first flow path section 2151, which is easier to flow through. For this reason, the liquid refrigerant flows in a detour before the second flow path section 2152, and the area in the flow path section 215 through which the liquid refrigerant flows increases.

[0066] In particular, in the metal plate 21, the dryness of the low-temperature refrigerant increases toward the downstream side of the flow path. Therefore, the dryness of the low-temperature fluid is high near the outlet, and the flow rate of the low-temperature fluid is high near the outlet. As a result, the pressure loss of the low-temperature fluid increases due to the second flow path portion 2152, and the effect of the second flow path portion 2152 acting as a resistance to the liquid refrigerant or two-phase refrigerant increases.

[0067] For example, in the case of a refrigerant with large latent heat such as ammonia, the circulation amount of the refrigerant flowing through the flow path is set low, so the flow rate of the refrigerant is slow near the inlet where the dryness is low compared to refrigerants with small latent heat such as R32 and R134a. Therefore, even if the second flow path section 2152 is provided near the inlet or in the center of the flow path, the pressure loss of the refrigerant is small, so it is difficult for the second flow path section 2152 to function as a flow path section with high resistance. In such a case, the second flow path section 2152 can be provided in an area where the flow rate of the refrigerant is fast, that is, by providing the second flow path section 2152 closer to the outlet than the inlet, the second flow path section 2152 can function as a flow path section with high flow resistance. This suppresses the uneven flow of the liquid refrigerant in the metal plate 21.

[0068] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments, and various modifications can be made. Each embodiment is not limited to an independent form, and can be combined as far as technically possible. [Explanation of symbols]

[0069] 1...Heat exchanger 1w…Side 1d, 1u...principal surface 2…Heat exchanger body 3, 4, 21, 22, 100...metal plate 5, 8...Inflow pipe 6, 7...Outflow pipe 15, 16, 17, 18...Space part 20...Laminate 21L, 100d, 100L…area 101...Virtual line 150, 160, 170, 180…Aperture 210, 220...recess 211, 221...area 212, 222...Bulkhead 213, 223...Outer periphery 214, 224...Protrusion 215, 225...flow path 251, 261, 272, 282...Through holes 252...Through hole (inflow port) 262...Through hole (outlet) 271...Through hole (outlet) 281...Through hole (inflow port) 2141, 2142, 2142a, 2142b, 2142c, 2142d, 2143, 2145...Protrusion 2151…First flow path section 2152…Second flow path section 2153…Third flow path section

Claims

1. A heat exchanger in which a plurality of metal plates are stacked, At least one of the plurality of metal plates has an inlet, an outlet, a partition wall, and a plurality of protrusions protruding from the partition wall, a flow path portion is formed on the partition wall by the plurality of protrusions, The flow path portion has a first flow path portion, a second flow path portion, and a third flow path portion between the inlet and the outlet, The first flow path portion, the second flow path portion, and the third flow path portion are arranged in this order from the inlet to the outlet. A flow path resistance of the second flow path portion is greater than a flow path resistance of each of the first flow path portion and the third flow path portion. heat exchanger.

2. 2. The heat exchanger according to claim 1, A flow path cross-sectional area of ​​the second flow path portion is smaller than each of the flow path cross-sectional areas of the first flow path portion and the third flow path portion. heat exchanger.

3. 3. The heat exchanger according to claim 2, In the second flow path portion, an area occupied by the protrusions per unit area of ​​the second flow path portion is higher than an area occupied by the protrusions per unit area of ​​the first flow path portion and an area occupied by the protrusions per unit area of ​​the first flow path portion and an area occupied by the protrusions per unit area of ​​the third flow path portion, respectively. heat exchanger.

4. 3. A heat exchanger according to claim 1 or 2, The second flow path portion is disposed closer to the inlet than the outlet. heat exchanger.

5. 3. A heat exchanger according to claim 1 or 2, The second flow path portion is disposed closer to the outlet than the inlet. heat exchanger.

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