Heat exchanger and air conditioner using the same

Abstract

To enable a first fluid to be returned in a shell even when the shell has a less inner diameter and tubes have a less interval.SOLUTION: A heat exchanger 100 comprises a shell 10 and a plurality of tubes 20 provided in the shell, and has an inflow region Si which is set on one side of the shell and in which a first fluid flows, a return region Sr which is set on the other side of the shell, and an outflow region So which is set on the one side or the other side of the shell and out of which the first fluid L1 flows, wherein the plurality of tubes include a going-way tube 20(a) which guides the first fluid from the inflow region to the return region, and a return-way tube 20(b) which guides the first fluid from the return region to the outflow region. The heat exchanger further comprises partition plates 30 (a,b) which are provided in the shell to partition off the inflow region, return region, and outflow region and through which at least the going-way tube or the return-way tube runs.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a heat exchanger and an air conditioner using the heat exchanger.

Background Art

[0002] As a conventional heat exchanger, there is a so-called shell-and-tube heat exchanger including a shell and a plurality of tubes provided in the shell, which performs heat exchange between a first fluid flowing in the tubes and a second fluid flowing outside the tubes in the shell.

[0003] In this type of heat exchanger, an inflow region where the first fluid flows in, a heat exchange region where the second fluid flows and exchanges heat with the first fluid, and an outflow region where the first fluid flows out are provided in the shell.

[0004] In such a configuration, the one shown in Patent Document 1 provides the inflow region and the outflow region on one side of the shell, provides the heat exchange region at the central portion of the shell, and provides a turning region for turning the first fluid on the other side of the shell.

[0005] More specifically, the heat exchanger shown in the same document includes an upstream tube that guides the first fluid flowing into the inflow region to the turning region, and a return tube that guides the first fluid guided to the turning region to the outflow region, and the inflow region and the outflow region are partitioned by a partition plate provided between the upstream tube and the return tube.

[0006] According to such a configuration, compared with a configuration in which the first fluid flowing into one side of the shell flows out from the other side of the shell without turning back, the number of the first fluid flowing in can be reduced without changing the total number of tubes. Thereby, the flow velocity of the first fluid can be increased, and the heat transfer rate can be improved.

[0007] On the other hand, as another aspect for improving the heat transfer rate, an aspect (small inner diameter and high integration) of reducing the inner diameter of the shell and narrowing the tube spacing can be cited to increase the flow velocity of the second fluid flowing outside the tube.

[0008] However, when the tube spacing is narrowed in this way, it becomes impossible to provide a partition plate used in the aspect of turning back the first fluid described above between the forward tube and the return tube.

[0009] Of course, an aspect of widening the tube spacing only at the portion where the partition plate is inserted can be adopted. In this case, however, it leads to an increase in the outer diameter of the shell, and when the second fluid is a two-phase refrigerant, there is also a risk of causing uneven flow.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0011] Therefore, the present invention has been made to solve the above-described problems at once, and the main problem is to make it possible to turn back the first fluid in the shell while reducing the inner diameter of the shell and narrowing the tube spacing.

Means for Solving the Problems

[0012] That is, the heat exchanger according to the present invention includes a shell and a plurality of tubes provided in the shell, and exchanges heat between a first fluid flowing in the tubes and a second fluid flowing outside the plurality of tubes in the shell. The shell has an inflow region set on one side of the shell for the first fluid to flow in, a turning region set on the other side of the shell, and an outflow region set on one side or the other side of the shell for the first fluid to flow out. The plurality of tubes at least include an outgoing tube that guides the first fluid from the inflow region to the turning region and a returning tube that guides the first fluid from the turning region to the outflow region. The heat exchanger further includes a partition plate provided in the shell for partitioning the inflow region, the turning region, and the outflow region and through which at least the outgoing tube or the returning tube penetrates.

[0013] According to the heat exchanger configured as described above, since the partition plate is provided so that the outgoing tube and the returning tube penetrate through it, the arrangement of this partition plate is not hindered from reducing the inner diameter of the shell or narrowing the interval between the outgoing tube and the returning tube. Thereby, while achieving a reduction in the diameter of the shell and a high integration of the tubes, the first fluid can be turned back in the shell, so that the flow rates of the first fluid and the second fluid can be improved, and a dramatic improvement in the heat transfer rate can be achieved compared with the prior art.

[0014] If the outgoing tube and the returning tube are connected in a U shape to form an integral single tube, in order to achieve a reduction in the diameter of the shell and a high integration of the tubes, U-shaped tubes with various bending methods are required, and moreover, the arrangement is restricted so that the U-shaped tubes do not interfere with each other, resulting in a decrease in manufacturability. Therefore, in order to ensure manufacturability, it is preferable that the outgoing tube and the returning tube are separate from each other. With such a configuration, not only can the manufacturability be ensured, but also the degree of freedom in design can be greatly improved, for example, by using tubes with different diameters as the forward tube and the return tube. Moreover, compared with the case of using a U-shaped tube, the interval between the forward tube and the return tube can be narrowed, thereby improving the flow velocity of the second fluid.

[0015] Preferably, the lengths of the forward tube and the return tube are different from each other. With such a configuration, the inflow region and the outflow region can be set in a region shifted in the axial direction of the shell, and these regions can be partitioned by a partition plate through which the forward tube and the return tube penetrate.

[0016] Preferably, the outflow region, the inflow region, and the turning region are arranged in this order from one side to the other side of the shell. With such a configuration, in the inflow region, not only the forward tube connecting the inflow region and the turning region but also the return tube connecting the turning region and the outflow region pass through. Therefore, the first fluid flowing into the inflow region hits a large number of tubes, and its flow can be disturbed, thereby improving the heat exchange efficiency.

[0017] As a more specific embodiment, there can be mentioned an embodiment in which the shell has a heat exchange region through which the second fluid flows, and the heat exchange region is partitioned by the partition plate with respect to the inflow region, the turning region, and the outflow region.

[0018] In order to improve the heat transfer rate in the heat exchange region, it is preferable to provide a baffle in the heat exchange region for changing the flow direction of the second fluid.

[0019] When the second fluid is in a low-temperature two-phase state, there is a concern that dryout may occur on the downstream side in the heat exchange region, resulting in a decrease in the heat transfer rate. Therefore, it is preferable that a plurality of the baffles are provided in the heat exchange region, and the interval between the baffles adjacent to each other on the downstream side of the second fluid is narrower than the interval between the baffles adjacent to each other on the upstream side of the second fluid. In this case, the flow velocity of the second fluid on the downstream side of the heat exchange region can be further increased, and a decrease in the heat transfer coefficient due to dryout can be suppressed.

[0020] In order to further improve the heat transfer coefficient in the heat exchange region, it is preferable to provide an extended heat transfer surface provided on the outer surface of the tube in the heat exchange region.

[0021] A plurality of the extended heat transfer surfaces are provided in the heat exchange region, and it is preferable that the interval between the extended heat transfer surfaces adjacent to each other on the downstream side of the second fluid is narrower than the interval between the extended heat transfer surfaces adjacent to each other on the upstream side of the second fluid. In this case, on the downstream side where dryout can occur as described above, the flow velocity of the second fluid can be increased, and a decrease in the heat transfer coefficient due to dryout can be suppressed.

[0022] It is preferable to provide a second baffle provided between the adjacent tubes in the heat exchange region. In this case, a forward path and a return path can be formed for the second fluid flowing in the heat exchange region in the shell, the flow velocity of the second fluid can be increased, and heat transfer between the first fluid and the second fluid can be promoted.

[0023] It is preferable that a concave portion or a convex portion is formed on the inner surface of the tube. In this case, it is possible to expand the heat transfer area on the inner peripheral surface of the tube and promote the turbulent flow of the first fluid flowing in the tube, thereby improving the heat exchange amount.

[0024] Further, the air conditioner according to the present invention is characterized by including the heat exchanger described above, and according to such an air conditioner, the same operational effects as those of the above-described heat exchanger can be obtained.

Advantages of the Invention

[0025] According to the present invention configured as described above, while reducing the inner diameter of the shell and narrowing the interval between the tubes, the first fluid can be folded back within the shell, enabling an increase in the flow rates of the first fluid and the second fluid, and achieving a dramatic improvement in the heat transfer coefficient compared to the prior art.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

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Figure 8

Figure 9

Figure 10

Figure 11

Modes for Carrying Out the Invention

[0027] Hereinafter, an embodiment of the heat exchanger according to the present invention will be described with reference to the drawings.

[0028] The heat exchanger according to the present embodiment is used for at least one of the outdoor heat exchanger and the indoor heat exchanger in an air conditioner including a refrigerant circuit to which a compressor, an outdoor heat exchanger, a throttling mechanism, and an indoor heat exchanger are connected.

[0029] Specifically, as shown in FIG. 1, this heat exchanger 100 is a so-called shell-and-tube heat exchanger, and includes a shell 10 and a plurality of tubes 20 provided in the shell 10, and exchanges heat between a first fluid L1 flowing in the tubes 20 and a second fluid L2 flowing outside the tubes 20 in the shell 10.

[0030] As shown in FIG. 1, the heat exchanger 100 of the present embodiment is configured such that the first fluid L1 turns back at least once in the shell 10. In other words, the first fluid L1 flowing into one side of the shell 10 is guided to the other side of the shell 10 and then guided back to one side of the shell 10 again.

[0031] The shell 10 has a cylindrical shape. As shown in FIG. 1, an inflow region Si into which the first fluid L1 flows, an outflow region So from which the first fluid L1 flows out, and a heat exchange region Se through which the second fluid L2 flows in and out and heat exchange is performed between the first fluid L1 and the second fluid L2 are provided in its internal space.

[0032] The inflow region Si is set on one axial side of the shell 10, and a first inflow port Pa for allowing the first fluid L1 to flow into the inflow region Si is provided.

[0033] The outflow region So is set on one axial side of the shell 10, and a first outflow port Pb for allowing the first fluid L1 to flow out from the outflow region So is provided.

[0034] In the present embodiment, the inflow region Si and the outflow region So are provided adjacent to each other. Here, the outflow region So is provided outside (one axial side) the inflow region Si. However, the outflow region So may be provided inside (the other axial side) the inflow region Si.

[0035] Also, the first inflow port Pa and the first outflow port Pb are arranged here so as to sandwich the axis of the shell 10, and open in directions facing each other. However, the first inflow port Pa and the first outflow port Pb do not necessarily have to open in directions facing each other, and their arrangement may be changed as appropriate, for example, they may open in directions orthogonal to each other.

[0036] The heat exchange region Se is set at the central portion in the axial direction of the shell 10, and is provided with a second inflow port Pc for allowing the second fluid L2 to flow into the heat exchange region Se and a second outflow port Pd for allowing the second fluid L2 to flow out from the heat exchange region Se.

[0037] The second inflow port Pc and the second outflow port Pd are arranged, for example, so as to sandwich the axis of the shell 10, and open on the outer surface of the shell 10 in directions facing each other. In this embodiment, the second inflow port Pc opens in the same direction as the first inflow port Pa, and the second outflow port Pd opens in the same direction as the first outflow port Pb. However, the second inflow port Pc and the second outflow port Pd do not necessarily have to open in directions facing each other, and their arrangement may be changed as appropriate, for example, they may open in directions orthogonal to each other.

[0038] Also, one of the second inflow port Pc and the second outflow port Pd is provided on one side in the axial direction in the heat exchange region Se, and the other is provided on the other side in the axial direction in the heat exchange region Se. With such an arrangement, the second fluid L2 flowing in from the second inflow port Pc flows along the axial direction of the shell 10 and exchanges heat with the first fluid L1 flowing in the tube 20 described later, and then flows out from the second outflow port Pd.

[0039] And in the internal space of the shell 10 of this embodiment, a turning-back region Sr is provided which is set on the other side in the axial direction and turns back the first fluid L1.

[0040] Here, one turning region Sr is provided in the internal space of the shell 10, and this turning region Sr is arranged on the outer side (the other axial direction side) of the heat exchange region Se and is provided adjacent to the heat exchange region Se.

[0041] The plurality of tubes 20 are those through which the first fluid L1 flows. These tubes 20 at least include an upstream tube 20a that guides the first fluid L1 from the inflow region Si to the turning region Sr and a return tube 20b that guides the first fluid L1 from the turning region Sr to the outflow region So. Here, a plurality of upstream tubes 20a are arranged close to the first inflow port Pa and the second inflow port Pc side, and a plurality of return tubes 20b are arranged close to the first outflow port Pb and the second outflow port Pd side.

[0042] The upstream tube 20a extends along the axial direction of the shell 10, and the upstream opening is located in the inflow region Si, and the downstream opening is arranged to be located in the turning region Sr. That is, the upstream tube 20a spans the inflow region Si, the heat exchange region Se, and the turning region Sr. Here, a plurality of upstream tubes 20a are provided parallel to the axial direction of the shell 10. However, the number of upstream tubes 20a can be appropriately changed, and the extending direction of the upstream tube 20a may be inclined with respect to the axial direction of the shell 10.

[0043] The return tube 20b is separate from the upstream tube 20a here and extends along the axial direction of the shell 10. The upstream opening is located in the turning region Sr, and the downstream opening is arranged to be located in the outflow region So. That is, the return tube 20b spans the turning region Sr, the heat exchange region Se, and the outflow region So. Here, a plurality of return tubes 20b are provided parallel to the axial direction of the shell 10. However, the number of return tubes 20b can be appropriately changed, and the extending direction of the return tube 20b may be inclined with respect to the axial direction of the shell 10.

[0044] The above-mentioned forward tube 20a and return tube 20b have different length dimensions, and here the return tube 20b is longer than the forward tube 20a.

[0045] However, as shown in FIG. 1, the heat exchanger 100 of the present embodiment is provided in the shell 10, partitions the inflow region Si, the return region Sr, and the outflow region So, and further includes a partition plate 30 through which at least the forward tube 20a or the return tube 20b penetrates.

[0046] This partition plate 30 partitions regions adjacent to each other among the above-mentioned inflow region Si, outflow region So, heat exchange region Se, and return region Sr. In this embodiment, a first partition plate 30a that partitions the outflow region So and the inflow region Si, a second partition plate 30b that partitions the inflow region Si and the heat exchange region Se, and a third partition plate 30c that partitions the heat exchange region Se and the return region Sr are provided.

[0047] The partition plate 30 of the present embodiment is provided so as to be orthogonal to the axial direction of the shell 10, and here it is provided so as to be orthogonal to the forward tube 20a and the return tube 20b.

[0048] The first partition plate 30a is penetrated by the return tube 20b, and here it is provided so as to be orthogonal to the return tube 20b, in other words, so as to be orthogonal to the axis of the shell 10.

[0049] The second partition plate 30b is penetrated by the forward tube 20a and the return tube 20b, and here it is provided so as to be orthogonal to the forward tube 20a and the return tube 20b, in other words, so as to be orthogonal to the axis of the shell 10.

[0050] The third partition plate 30c is penetrated by the forward tube 20a and the return tube 20b, and here it is provided so as to be orthogonal to the forward tube 20a and the return tube 20b, in other words, so as to be orthogonal to the axis of the shell 10.

[0051] Here, the experimental results shown in FIG. 2 compare the heat exchange amounts between the heat exchanger 100 of the present embodiment and a heat exchanger with a conventional configuration. As can be seen from these experimental results, according to the heat exchanger 100 of the present embodiment in which the inflow region Si, the outflow region So, the heat exchange region Se, and the return region Sr are partitioned by the partition plate 30, it can be understood that the heat exchange amount is improved as compared with the conventional configuration that does not use the partition plate 30.

[0052] Thus, in the heat exchanger 100 of the present embodiment, since the partition plate 30 is provided so that the forward path tube 20a and the return path tube 20b penetrate therethrough, the arrangement of this partition plate 30 is not hindered by reducing the inner diameter of the shell 10 or narrowing the interval between the forward path tube 20a and the return path tube 20b. Thereby, while reducing the diameter of the shell 10 and achieving high integration of the tubes 20, the first fluid L1 can be folded back within the shell 10, so that the flow velocities of the first fluid L1 and the second fluid L2 can be improved, and a dramatic improvement in the heat transfer coefficient can be achieved as compared with the prior art.

[0053] Furthermore, since the partition plate 30 is provided so that the forward path tube 20a and the return path tube 20b penetrate therethrough, various aspects such as the arrangement of the forward path tube 20a and the return path tube 20b, the number and arrangement of the return regions Sr, and the arrangement of the inflow region Si and the outflow region So can be adopted as described later, and the degree of freedom in arrangement can be improved as compared with the conventional configuration.

[0054] In addition, since the forward path tube 20a and the return path tube 20b are separate from each other, the manufacturability is good as compared with the case of using a U-shaped integral tube. Furthermore, the degree of freedom in design can be greatly improved, for example, by using tubes with different diameters as the forward path tube 20a and the return path tube 20b. Moreover, since the interval between the forward path tube 20a and the return path tube 20b can be narrowed as compared with the case of using a U-shaped tube, an improvement in the flow velocity of the second fluid L2 can also be achieved thereby.

[0055] Furthermore, an outflow region So, an inflow region Si, and a return region Sr are arranged in this order from one side to the other side of the shell 10. Since not only the forward tube 20a but also the return tube 20b passes through the inflow region Si, the first fluid L1 flowing into the inflow region Si hits a large number of tubes 20, and its flow can be disturbed, thereby improving the heat exchange efficiency.

[0056] Note that the present invention is not limited to the above-described embodiment.

[0057] For example, in the above-described embodiment, one return region Sr is provided in the internal space of the shell 10. However, as shown in FIG. 3, a plurality of return regions Sr may be provided in the internal space of the shell 10. More specifically, the tube 20 of this heat exchanger 100 further includes an intermediate tube 20c that guides the first fluid L1 from one return region Sr to another return region Sr, in addition to the forward tube 20a and the return tube 20b. With such a configuration, the number of tubes 20 into which the first refrigerant flowing into the inflow region Si flows can be further reduced, and the flow velocity of the first fluid L1 can be further improved.

[0058] In the above-described embodiment, a plurality of forward tubes 20a are arranged close to the first inflow port Pa and the second inflow port Pc side, and a plurality of return tubes 20b are arranged close to the first outflow port Pb and the second outflow port Pd side. However, as shown in FIG. 4, the forward tube 20a and the return tube 20b may be alternately arranged from the first inflow port Pa and the second inflow port Pc side toward the first outflow port Pb and the second outflow port Pd side.

[0059] Here, when the second fluid L2 is in a low-temperature two-phase state, the high-density liquid phase flows on the outer side in the shell 10, and the low-density gas phase flows in the central part in the shell 10. Therefore, in order to increase the amount of heat exchange in the gas phase, which has a low heat transfer coefficient, multiple outward tubes 20a may be arranged in the center of the shell 10, and multiple return tubes 20b may be arranged outside the return tubes 20b within the shell 10, as shown in Figure 5. With this configuration, since the outward tube 20a is disposed at the center of the shell 10, a temperature difference between the gas phase of the second fluid L2 and the first fluid L1 flowing inside the outward tube 20a can be ensured, and the amount of heat exchange of the gas phase can be increased. This effect is particularly noticeable when the proportion of the gas phase contained in the low-temperature two-phase second fluid L2 is high.

[0060] Furthermore, the heat exchanger 100 according to the present invention may include a baffle 40 provided in the heat exchange area Se to change the flow direction of the second fluid L2, as shown in FIG. The baffle 40 obstructs the flow of the second fluid L2 from the second inflow port Pc to the second outflow port Pd. Here, a plurality of baffles 40 are arranged in a staggered manner from the second inflow port Pc to the second outflow port Pd, so that the second fluid L2 flows in a serpentine manner from the second inflow port Pc to the second outflow port Pd. With this configuration, the flow path of the second fluid L2 in the heat exchange area Se can be lengthened, so that the heat transfer coefficient in the heat exchange area Se can be further improved.

[0061] Incidentally, when the second fluid L2 is a low-temperature two-phase fluid, there is a concern that dryout will occur on the downstream side of the heat exchange region Se, resulting in a decrease in the heat transfer coefficient. Therefore, in a configuration in which multiple baffles 40 are provided as described above, as shown in FIG. 7, the spacing X2 between adjacent baffles 40 on the downstream side of the second fluid L2 may be narrower than the spacing X1 between adjacent baffles 40 on the upstream side of the second fluid L2. With this configuration, the flow velocity of the second fluid L2 on the downstream side of the heat exchange area Se can be further increased, and the decrease in the heat transfer coefficient due to dryout can be suppressed.

[0062] Furthermore, as the heat exchanger 100 according to the present invention, as shown in FIG. 8, in the heat exchange region Se, an extended heat transfer surface 50 provided on the outer surface of the tube 20 may be provided. This extended heat transfer surface 50 is formed by fins provided on the outer peripheral surfaces of the forward tube 20a and the return tube 20b. Here, a plurality of fins are provided along the longitudinal direction of the forward tube 20a and the return tube 20b. With such a configuration, since the extended heat transfer surface 50 is provided on the forward tube 20a and the return tube 20b, further improvement in the heat transfer rate in the heat exchange region Se can be achieved.

[0063] In the configuration in which the fins serving as the extended heat transfer surface 50 are provided in this way, as shown in FIG. 9, a plurality of extended heat transfer surfaces 50 are provided in the heat exchange region Se, and the interval Y2 between the adjacent extended heat transfer surfaces 50 on the downstream side of the second fluid L2 is made smaller than the interval Y1 between the adjacent extended heat transfer surfaces 50 on the upstream side of the second fluid L2. With such a configuration, the flow velocity of the second fluid L2 can be increased on the downstream side where dryout can occur as described above, and a decrease in the heat transfer rate due to dryout can be suppressed.

[0064] Furthermore, as the heat exchanger 100 according to the present invention, as shown in FIG. 10, in the heat exchange region Se, a second baffle 60 provided between the adjacent tubes 20 may be provided. This second baffle 60 is a flat plate extending in parallel with the forward tube 20a and the return tube 20b. As shown in the upper part of FIG. 10, it may be provided between the forward tube 20a and the return tube 20b, or as shown in the lower part of FIG. 10, it may be provided between the forward tubes 20a or between the return tubes 20b. In this embodiment, the second inflow port Pc and the second outflow port Pd are arranged opposite to each other, but the arrangement of these second inflow port Pc and second outflow port Pd is not limited to this and may be changed as appropriate. With such a configuration, since the second fluid L2 flows while meandering from the second inflow port Pc toward the second outflow port Pd, the flow path of the second fluid L2 in the heat exchange region Se can be lengthened, and thus further improvement in the heat transfer coefficient in the heat exchange region Se can be achieved.

[0065] Further, as shown in FIG. 11, the forward path tube 20a and the return path tube 20b may have concave portions 21 such as grooves formed on the inner surface, or may have convex portions such as protrusions (not shown). If this is the case, it becomes possible to increase the heat transfer area on the inner peripheral surface of the tube 20 and promote the turbulent flow of the first fluid L1 flowing through the tube 20, and thus the heat exchange amount can be improved.

[0066] Needless to say, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit thereof.

Explanation of Reference Numerals

[0067] 100 ··· Heat exchanger 10 ··· Shell L1 ··· First fluid L2 ··· Second fluid Si ··· Inflow region So ··· Outflow region Se ··· Heat exchange region Sr ··· Turning-back region 20a ··· Forward path tube 20b ··· Return path tube 30 ··· Partition plate 40 ··· Baffle 50 ··· Extended heat transfer surface 60 ··· Second baffle

Claims

1. A shell-and-tube heat exchanger comprising a shell and a plurality of tubes provided within the shell, for performing heat exchange between a first fluid flowing through the tubes and a second fluid flowing outside the plurality of tubes within the shell, wherein the shell has an inflow region set on one side of the shell for the first fluid to flow in, a turning region set on the other side of the shell, and an outflow region set on one side or the other side of the shell for the first fluid to flow out, the plurality of tubes at least include a forward tube for guiding the first fluid from the inflow region to the turning region and a return tube for guiding the first fluid from the turning region to the outflow region, and a plurality of partition plates provided within the shell for partitioning the inside of the shell such that the inflow region, the turning region, and the outflow region are arranged along the direction in which the plurality of tubes extend, and at least the forward tube or the return tube penetrates each of the plurality of partition plates.

2. The shell-and-tube heat exchanger according to claim 1, wherein the forward tube and the return tube are separate from each other.

3. The shell-and-tube heat exchanger according to claim 1 or 2, wherein the lengths of the forward tube and the return tube are different from each other.

4. The shell-and-tube heat exchanger according to any one of claims 1 to 3, wherein the outflow region, the inflow region, and the turning region are arranged in this order from one side to the other side of the shell.

5. The shell has a heat exchange region through which the second fluid flows, and the heat exchange region is partitioned by the partition plates with respect to the inflow region, the turning region, and the outflow region. The shell-and-tube heat exchanger according to any one of claims 1 to 4.

6. The shell-and-tube heat exchanger according to claim 5, comprising a baffle provided in the heat exchange region for changing the flow direction of the second fluid.

7. A plurality of the baffles are provided in the heat exchange region, The shell-and-tube heat exchanger according to claim 6, wherein the distance between the baffles adjacent to each other on the downstream side of the second fluid is narrower than the distance between the baffles adjacent to each other on the upstream side of the second fluid.

8. The shell-and-tube heat exchanger according to any one of claims 5 to 7, comprising an extended heat transfer surface provided on the outer surface of the tube in the heat exchange region.

9. A plurality of the extended heat transfer surfaces are provided in the heat exchange region, The shell-and-tube heat exchanger according to claim 8, wherein the distance between the extended heat transfer surfaces adjacent to each other on the downstream side of the second fluid is narrower than the distance between the extended heat transfer surfaces adjacent to each other on the upstream side of the second fluid.

10. The shell-and-tube heat exchanger according to any one of claims 5 to 9, comprising a second baffle provided between the tubes adjacent to each other in the heat exchange region.

11. The shell-and-tube heat exchanger according to any one of claims 1 to 10, wherein a concave portion or a convex portion is formed on the inner surface of the tube.

12. An air conditioner comprising the shell-and-tube heat exchanger according to any one of claims 1 to 11.

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