heat exchanger

Abstract

To provide a heat exchanger that can reduce the temperature difference of the main body. [Solution] The heat exchanger according to the embodiment includes a main body shell including an inlet nozzle and an outlet nozzle, a shroud that defines a recirculating flow path communicating with a part of the outlet opening and the outlet nozzle, a heat exchange element disposed within the shroud, an inlet duct that defines a flow path for the primary heat transfer medium from the inlet nozzle to the inlet opening, and an outlet duct that defines a direct flow path for the primary heat transfer medium from the outlet opening to the outlet nozzle. The outlet duct includes a first partition plate that divides the flow of the primary heat transfer medium from the outlet opening into a recirculating flow path and a direct flow path.

Description

Technical Field

[0001] This embodiment relates to a heat exchanger.

Background Art

[0002] A heat exchanger that exchanges heat between a primary heat medium and a secondary heat medium is known. As an example of a heat exchanger, a high-temperature heat exchanger installed in a thermal power plant or the like can be mentioned.

[0003] The main body cylinder of the heat exchanger includes an inlet nozzle into which the primary heat medium flows and an outlet nozzle from which the primary heat medium flows out. The high-temperature primary heat medium flowing in from the inlet nozzle exchanges heat with the low-temperature secondary heat medium flowing inside the heat transfer tubes arranged in the main body cylinder. As a result, the primary heat medium is cooled and the temperature of the primary heat medium decreases. The primary heat medium at a lower temperature flows out from the outlet nozzle.

[0004] Thus, the temperature of the primary heat medium is high at the inlet nozzle and low at the outlet nozzle. As a result, the temperature of the main body cylinder becomes high in the vicinity of the inlet nozzle and low in the vicinity of the outlet nozzle. Therefore, when the temperature difference of the main body cylinder increases, a large thermal stress can be generated in the main body cylinder. In this case, the main body cylinder can be deformed into an arch shape. Further, the main body cylinder is designed as a pressure vessel. Since the strength of the material of the main body cylinder decreases as the temperature increases, the main body cylinder is designed according to the temperature of the inlet nozzle. Therefore, in the vicinity of the outlet nozzle of the main body cylinder, an excessive design may be required.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the embodiment is to provide a heat exchanger capable of reducing the temperature difference of the main body cylinder. [Means for solving the problem]

[0007] The heat exchanger according to this embodiment includes a main body shell including an inlet nozzle into which a primary heat transfer medium flows and an outlet nozzle through which the primary heat transfer medium flows out; a shroud housed within the main body shell, including an inlet opening into which the primary heat transfer medium flows and an outlet opening through which the primary heat transfer medium flows out, and defining a recirculation flow path between the main body shell and the shroud that communicates with a part of the outlet opening and also with the outlet nozzle; a heat exchange element disposed within the shroud, which exchanges heat between a secondary heat transfer medium flowing inside and a primary heat transfer medium; an inlet duct defining a flow path for the primary heat transfer medium from the inlet nozzle to the inlet opening; and an outlet duct defining a direct flow path for the primary heat transfer medium from the outlet opening to the outlet nozzle. The outlet duct includes a first partition plate that divides the flow of the primary heat transfer medium from the outlet opening into a recirculation flow path and a direct flow path. [Effects of the Invention]

[0008] According to this embodiment, the temperature difference between the main body and the surrounding material can be reduced. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a cross-sectional view showing a heat exchanger according to the first embodiment. [Figure 2] Figure 2 is a cross-sectional view along line AA shown in Figure 1. [Figure 3] Figure 3 is a partially enlarged cross-sectional view of the heat exchanger shown in Figure 1. [Figure 4] Figure 4 is a cross-sectional view along line BB shown in Figure 2. [Figure 5] Figure 5 is a cross-sectional view along the CC line shown in Figure 2. [Figure 6] Figure 6 is a partially enlarged cross-sectional view showing a typical heat exchanger. [Figure 7] Figure 7 is a cross-sectional view of the DD line shown in Figure 6. [Figure 8] Figure 8 is a partially enlarged cross-sectional view showing a heat exchanger according to the second embodiment. [Figure 9] Figure 9 is a cross-sectional view along the EE line shown in Figure 8. [Figure 10] Figure 10 is a cross-sectional view showing a typical heat exchanger. [Figure 11] Figure 11 is a cross-sectional view showing a modified example of the heat exchanger shown in Figure 9. [Modes for carrying out the invention]

[0010] The embodiments will be described below with reference to the drawings.

[0011] (First Embodiment) A heat exchanger according to the first embodiment will be described with reference to Figures 1 to 7. The heat exchanger according to this embodiment may be installed in a power plant. For example, the heat exchanger may be used as a heat exchanger that heats boiler feedwater using turbine extraction steam from a thermal power plant and reduces the degree of superheating of the steam.

[0012] As shown in Figures 1 and 2, the heat exchanger 1 according to this embodiment is configured to exchange heat between a relatively high-temperature primary heat transfer medium M1 and a relatively low-temperature secondary heat transfer medium M2. The heat exchanger 1 includes a main body shell 10, a shroud 20, a heat transfer tube group 30, an inlet duct 40, and an outlet duct 50. The following description will use a shell-and-tube type heat exchanger as an example.

[0013] The main body 10 includes a body 11, an end wall 12, an inlet nozzle 13, an outlet nozzle 14, and a bonnet section 15. Below, we will describe an example in which the inlet nozzle 13 is located on the upper side of the body 11 and the outlet nozzle 14 is located on the lower side of the body 11, as shown in Figure 1. However, the arrangement of the inlet nozzle 13 and the outlet nozzle 14 is not limited to the vertical direction and is arbitrary.

[0014] As shown in Figures 1 and 2, the fuselage 11 is formed in a cylindrical shape. One end of the fuselage 11 is closed by an end wall 12. The other end of the fuselage 11 is closed by a bonnet portion 15.

[0015] The inlet nozzle 13 is configured such that the primary heat medium M1 flows in, and the outlet nozzle 14 is configured such that the primary heat medium M1 flows out. The inlet nozzle 13 is disposed on one side (the upper side in FIG. 1) with respect to the central axis 10X of the main body cylinder 10, and the outlet nozzle 14 is disposed on the other side (the lower side in FIG. 1) with respect to the central axis 10X of the main body cylinder 10. The inlet nozzle 13 and the outlet nozzle 14 are each formed in a cylindrical shape and have central axes 13X, 14X (see FIGS. 2 and 3) extending in a direction perpendicular to the central axis 10X of the main body cylinder 10. The central axis 13X of the inlet nozzle 13 and the central axis 14X of the outlet nozzle 14 may be arranged on a straight line.

[0016] As shown in FIG. 1, a plurality of inlet nozzles 13 and a plurality of outlet nozzles 14 may be formed in the body 11. In the example shown in FIG. 1, three inlet nozzles 13 and three outlet nozzles 14 are formed in the body 11.

[0017] The bonnet portion 15 is formed at one end in the axial direction 10D of the main body cylinder 10. The axial direction 10D of the main body cylinder 10 is a direction along the central axis 10X of the main body cylinder 10. The bonnet portion 15 includes an inlet 15a through which the secondary heat medium M2 flows in and an outlet 15b through which the secondary heat medium M2 flows out. The interior of the bonnet portion 15 is partitioned into two spaces, and the secondary heat medium M2 flowing in from the inlet 15a is supplied to the heat transfer tubes 31 of the heat transfer tube group 30 through one space. The secondary heat medium M2 discharged from the heat transfer tubes 31 flows out from the outlet 15b through the other space.

[0018] A first partition plate 16 may be formed at the other end in the axial direction 10D of the main body cylinder 10. The first partition plate 16 is disposed at a position close to the end wall 12. A return flow path P1 (see FIG. 2) described later is defined between the first partition plate 16 and the bonnet portion 15. An end space 17 is formed between the first partition plate 16 and the end wall 12.

[0019] Multiple second compartment plates 18 may be formed on the body 11. The second compartment plates 18 are formed perpendicular to the axial direction 10D of the main body 10. The second compartment plates 18 extend from the outlet opening 22 of the shroud 20 (described later) to the inner surface of the main body 10 and are formed perpendicular to the outlet opening 22. The second compartment plates 18 are positioned between two adjacent outlet nozzles 14 in the axial direction 10D of the main body 10.

[0020] The shroud 20 is housed within the main body 10. The shroud 20 extends from the bonnet section 15 to the first compartment plate 16 of the main body 10.

[0021] As shown in Figures 1 and 2, the shroud 20 includes an inlet opening 21 through which the primary heat transfer medium M1 flows in, and an outlet opening 22 through which the primary heat transfer medium M1 flows out. The inlet opening 21 faces the inlet nozzle 13 and may be formed over the entire surface facing the inlet nozzle 13. In the example shown in Figures 1 and 2, the inlet opening 21 is formed over the entire upper surface of the shroud 20. The outlet opening 22 faces the outlet nozzle 14 and may be formed over the entire surface facing the outlet nozzle 14. In the example shown in Figures 1 and 2, the outlet opening 22 is formed over the entire lower surface of the shroud 20.

[0022] As shown in Figure 2, a recirculation channel P1 for the primary heat transfer medium M1 is formed around the shroud 20. The recirculation channel P1 is formed between the body 11 of the main body 10 and the shroud 20. The recirculation channel P1 communicates with a part of the outlet opening 22 and a part of the outlet nozzle 14. The recirculation channel P1 is a flow path for the primary heat transfer medium M1 that flows from a part of the outlet opening 22 through the space between the body 11 and the shroud 20 to the outlet nozzle 14. Near the inlet duct 40, the space around the inlet duct 40 constitutes a part of the recirculation channel P1. When viewed in a cross-section perpendicular to the axial direction 10D of the main body 10, the primary heat transfer medium M1 in the recirculation channel P1 flows circumferentially around the shroud 20.

[0023] The shroud 20 may include a curved wall 23 positioned between the inlet opening 21 and the outlet opening 22. The curved wall 23 faces the main body 10. A recirculation channel P1 is defined between the curved wall 23 and the body 11 of the main body 10. The curved wall 23 may be formed in an arc shape concentric with the body 11.

[0024] The heat transfer tube group 30 is an example of a heat exchange element. The heat transfer tube group 30 is arranged inside the shroud 20 and exchanges heat between a primary heat transfer medium M1 and a secondary heat transfer medium M2. The primary heat transfer medium M1 flows through the heat transfer tube group 30, and the secondary heat transfer medium M2 flows inside the heat transfer tubes 31. More specifically, as shown in Figures 1 and 2, the heat transfer tube group 30 is composed of a plurality of heat transfer tubes 31 through which the secondary heat transfer medium M2 flows. The primary heat transfer medium M1 flows around the heat transfer tubes 31. As shown in Figure 1, the heat transfer tubes 31 extend in the axial direction 10D of the main body shell 10 inside the shroud 20. As shown in Figure 2, when viewed in a cross section perpendicular to the axial direction 10D of the main body shell 10, the heat transfer tubes 31 may be arranged in a grid pattern or in a staggered pattern. As shown in Figure 1, a folded portion 32 of the heat transfer tube 31 is formed in the end space 17 described above.

[0025] As shown in Figures 2 and 3, secondary heat transfer fluid M2 flows into each heat transfer tube 31 from the inlet 15a described above. Primary heat transfer fluid M1, which flows in from the inlet opening 21 of the shroud 20, flows around each heat transfer tube 31. As a result, the primary heat transfer fluid M1 and the secondary heat transfer fluid M2 exchange heat. The secondary heat transfer fluid M2 that has exchanged heat flows out of each heat transfer tube 31 to the outlet 15b described above. The primary heat transfer fluid M1 that has exchanged heat flows out from the outlet opening 22.

[0026] As shown in Figure 2, the heat transfer tube group 30 according to this embodiment may be formed to follow the curved wall 23 when viewed in a cross section perpendicular to the axial direction 10D of the main body shell 10. More specifically, the heat transfer tubes 31 constituting the heat transfer tube group 30 may be arranged to follow the curved wall 23.

[0027] As shown in Figures 1 to 3, the inlet duct 40 defines the flow path of the primary heat transfer medium M1 from the inlet nozzle 13 to the inlet opening 21 of the shroud 20. The inlet duct 40 separates the flow path of the primary heat transfer medium M1 toward the inlet opening 21 from the aforementioned recirculation flow path P1. Multiple inlet ducts 40 may be formed in the main body 10 depending on the number of inlet nozzles 13. In the example shown in Figure 1, three inlet ducts 40 are formed in the main body 10. The entire inlet opening 21 is connected to the three inlet ducts 40.

[0028] As shown in Figure 2, the outlet duct 50 defines a direct flow path P2 for the primary heat transfer medium M1 from the outlet opening 22 of the shroud 20 to the outlet nozzle 14. The direct flow path P2 is a flow path for the primary heat transfer medium M1 that goes directly to the outlet nozzle 14 without passing through the recirculation flow path P1 described above. The outlet duct 50 may include a first partition plate 51 and a second partition plate 52.

[0029] The first partition plate 51 is configured to divide the flow of the primary heat transfer medium M1 from the outlet opening 22 of the shroud 20 into a recirculating flow path P1 and a direct flow path P2. One end of the first partition plate 51 is connected to the outlet opening 22. The other end of the first partition plate 51 is connected to the inner surface of the main body 10.

[0030] The first partition plate 51 extends in the axial direction 14D of the outlet nozzle 14. The axial direction 14D of the outlet nozzle 14 is the direction along the central axis 14X of the outlet nozzle 14. The axial direction 14D of the outlet nozzle 14 is also the direction along the central axis 13X of the inlet nozzle 13.

[0031] The first partition plate 51 is formed perpendicular to the outlet opening 22. As shown in Figures 4 and 5, when viewed in the axial direction 14D of the outlet nozzle 14, the first partition plate 51 may extend in the axial direction 10D of the main body 10. The first partition plate 51 may be formed parallel to the axial direction 10D of the main body 10. The first partition plate 51 may be located at the edge of the outlet nozzle 14. The portion of the outlet opening 22 that communicates with the recirculation channel P1 (the area shown as A1 in Figure 4) may be formed in a position that does not overlap with the outlet nozzle 14 when viewed in the axial direction 14D of the outlet nozzle 14. Both ends of the first partition plate 51 in the axial direction 10D of the main body 10 may be connected to the second partition plate 18.

[0032] As shown in Figure 2, the second partition plate 52 is configured to separate the flow path of the primary heat transfer medium M1 from the recirculation flow path P1 to the outlet nozzle 14 from the direct flow path P2. The direct flow path P2 is defined between the first partition plate 51 and the second partition plate 52.

[0033] One end of the second partition plate 52 is connected to the outer edge of the outlet opening 22. The other end of the second partition plate 52 may be located inside the outlet nozzle 14. The second partition plate 52 may extend into the outlet nozzle 14. As shown in Figures 4 and 5, the second partition plate 52 may extend in the axial direction 10D of the main body 10. The second partition plate 52 may be formed parallel to the axial direction 10D of the main body 10. Both ends of the second partition plate 52 in the axial direction 10D of the main body 10 may be connected to the second compartment plate 18.

[0034] As shown in Figure 2, the second partition plate 52 may include a constriction region 53 and an outlet region 54.

[0035] The diaphragm region 53 extends from and is connected to the shroud 20. The diaphragm region 53 is configured to narrow the cross-sectional area of ​​the direct flow path P2. The diaphragm region 53 may be formed to approach the first partition plate 51 as it moves from the outlet opening 22 toward the outlet nozzle 14. In this case, the cross-sectional area of ​​the direct flow path P2 in the diaphragm region 53 decreases toward the outlet nozzle 14. The width of the direct flow path P2 in the diaphragm region 53 may also narrow toward the outlet nozzle 14. For example, when viewed in the axial direction 10D of the main body 10, the diaphragm region 53 may be inclined with respect to the first partition plate 51.

[0036] The outlet region 54 extends from the throttling region 53 to the outlet nozzle 14. The outlet region 54 is configured to increase the flow velocity of the primary heat transfer medium M1 in the direct flow path P2. In this embodiment, the outlet region 54 may extend in the axial direction 14D of the outlet nozzle 14. In this case, the flow path cross-sectional area of ​​the direct flow path P2 in the outlet region 54 may remain constant as it approaches the outlet nozzle 14; for example, the flow path width of the direct flow path P2 in the outlet region 54 may be constant. However, the flow path cross-sectional area of ​​the direct flow path P2 in the outlet region 54 does not have to be constant as long as the flow velocity of the primary heat transfer medium M1 can be increased. A part of the outlet region 54 may be located inside the outlet nozzle 14.

[0037] The ratio of the flow path cross-sectional area of ​​the portion of the flow path cross-section of the outlet nozzle 14 that constitutes the direct flow path P2 may be smaller than the ratio of the flow path cross-sectional area of ​​the portion of the flow path cross-section of the outlet opening 22 that communicates with the direct flow path P2. More specifically, the following equation (1) may be satisfied. As shown in Figure 4, A1 is the flow path cross-sectional area of ​​the portion of the outlet opening 22 that communicates with the recirculation flow path P1. A2 is the flow path cross-sectional area of ​​the portion of the outlet opening 22 that communicates with the direct flow path P2. In Figure 4, the regions indicated by A1 and A2 are shown with a dot pattern. As shown in Figure 5, B1 is the flow path cross-sectional area of ​​the portion of the flow path cross-section of the outlet nozzle 14 that communicates with the recirculation flow path P1. B2 is the flow path cross-sectional area of ​​the portion of the flow path cross-section of the outlet nozzle 14 that constitutes the direct flow path P2. B1 and B2 are set at the connection point between the main body 10 and the outlet nozzle 14, as shown in Figure 2. In Figure 5, the regions indicated by B1 and B2 are shown with a dot pattern.

number

[0038] Next, the operation of the heat exchanger according to this embodiment, which has the above configuration, will be explained. Here, we will first explain the reason why a temperature difference occurs in the main body 10 of a typical heat exchanger 1 using Figures 6 and 7.

[0039] As shown in Figures 6 and 7, the high-temperature primary heat transfer medium M1 flows from the inlet nozzle 13 through the heat transfer tube group 30 located inside the body 11 of the main body 10. Since the low-temperature secondary heat transfer medium M2 flows inside the heat transfer tubes 31 of the heat transfer tube group 30, the primary heat transfer medium M1 exchanges heat with the secondary heat transfer medium M2. As a result, the primary heat transfer medium M1 is cooled and its temperature decreases. The primary heat transfer medium M1 that has undergone heat exchange flows out from the outlet nozzle 14.

[0040] Thus, the temperature of the primary heat transfer medium M1 flowing through the inlet nozzle 13 is relatively high, while the temperature of the primary heat transfer medium M1 flowing through the outlet nozzle 14 is relatively low. As a result, the temperature of the main body 10 is high near the inlet nozzle 13 and low near the outlet nozzle 14. Therefore, a temperature difference may occur in the main body 10.

[0041] In contrast, the heat exchanger 1 according to this embodiment can reduce such temperature differences in the main body 10. This will be explained below with reference to Figures 2 and 3.

[0042] As shown in Figures 2 and 3, the outlet duct 50 that defines the direct flow path P2 of the primary heat transfer medium M1 from the outlet opening 22 of the shroud 20 to the outlet nozzle 14 includes a first partition plate 51. The first partition plate 51 divides the flow of the primary heat transfer medium M1 from the outlet opening 22 into a recirculation flow path P1 and a direct flow path P2. As a result, the flow of the primary heat transfer medium M1 flowing out from the outlet opening 22 is divided into a flow into the recirculation flow path P1 and a flow into the direct flow path P2.

[0043] In the recirculation channel P1, the primary heat transfer medium M1 flows circumferentially around the shroud 20. More specifically, it first flows circumferentially towards the inlet duct 40 through the space between the curved wall 23 of the shroud 20 located on the side of the first partition plate 51 and the body 11 of the main body 10. Near the inlet duct 40, the primary heat transfer medium M1 flows circumferentially around the inlet duct 40 and the main body 10. Subsequently, it flows circumferentially through the space between the curved wall 23 of the shroud 20 located on the side of the second partition plate 52 and the body 11. After that, it flows through the space between the second partition plate 52 and the body 11. As a result, the primary heat transfer medium that has passed through the recirculation channel P1 reaches the outlet nozzle 14.

[0044] On the other hand, in the direct flow path P2, the primary heat transfer medium M1 flows towards the outlet nozzle 14 through the space between the first partition plate 51 and the second partition plate 52 of the outlet duct 50. More specifically, the flow path cross-sectional area of ​​the direct flow path P2 in the throttling region 53 decreases as it approaches the outlet nozzle 14, so the flow velocity of the primary heat transfer medium M1 in the direct flow path P2 is increased and the pressure is reduced. In the outlet region 54, the flow velocity of the primary heat transfer medium M1 flowing through the direct flow path P2 is further increased. In this way, the static pressure of the primary heat transfer medium M1 in the outlet region 54 decreases.

[0045] Downstream of the outlet region 54, the primary heat transfer medium M1 from the recirculating channel P1 and the primary heat transfer medium M1 from the direct channel P2 merge. As described above, the static pressure of the primary heat transfer medium M1 flowing through the direct channel P2 in the outlet region 54 is reduced, so the flow of the primary heat transfer medium M1 from the recirculating channel P1 is easily drawn into the flow of the primary heat transfer medium M1 from the direct channel P2. This compensates for the pressure drop in the flow of the primary heat transfer medium M1 from the recirculating channel P1, and ensures the flow of the primary heat transfer medium M1 from the outlet opening 22 of the shroud 20 toward the recirculating channel P1.

[0046] Incidentally, the primary heat transfer medium M1 flowing through the recirculation channel P1 is cooled by heat exchange with the secondary heat transfer medium M2 flowing inside the heat transfer tube 31. As a result, the temperature of the primary heat transfer medium M1 flowing through the recirculation channel P1 is lower than the temperature of the primary heat transfer medium M1 flowing from the inlet nozzle 13 to the inlet opening 21 of the shroud 20, thereby lowering the temperature of the main body 10. In particular, the temperature of the main body 10 can be effectively lowered near the inlet nozzle 13. In this way, the temperature difference between the temperature near the inlet nozzle 13 and the temperature near the outlet nozzle 14 of the body 11 can be reduced. Therefore, the thermal stress generated in the main body can be reduced.

[0047] Increasing the flow rate of the primary heat transfer medium M1 flowing through the recirculation channel P1 can enhance the temperature reduction effect of the main body shell 10. However, this increases the pressure loss in the flow of the primary heat transfer medium M1 when viewed as a heat exchanger 1, and may also increase the losses of the system including the heat exchanger 1. Increasing the cross-sectional area of ​​the recirculation channel P1 can reduce the pressure loss, but in this case, the diameter of the body 11 of the main body shell 10 increases, as does the thickness of the body 11, which is economically disadvantageous. For this reason, the proportion of the cross-sectional area of ​​the recirculation channel P1 (A1 mentioned above) at the outlet opening 22 of the shroud 20 may be set considering not only the temperature reduction effect but also losses and economics.

[0048] As described above, according to this embodiment, the outlet duct 50 that defines the direct flow path P2 of the primary heat transfer medium M1 from the outlet opening 22 to the outlet nozzle 14 includes a first partition plate 51. The first partition plate 51 divides the flow of the primary heat transfer medium M1 from the outlet opening 22 into a recirculation flow path P1 and a direct flow path P2. This allows the flow of the primary heat transfer medium M1 flowing out from the outlet opening 22 to be divided into a flow to the recirculation flow path P1 and a flow to the direct flow path P2. As a result, the heat-exchanged primary heat transfer medium M1 can flow into the recirculation flow path P1, and the temperature of the main body 10 near the inlet nozzle 13 can be reduced. This reduces the temperature difference of the main body 10.

[0049] Furthermore, according to this embodiment, the first partition plate 51 extends in the axial direction 14D of the outlet nozzle 14. This reduces the pressure loss of the flow of the primary heat transfer medium M1 from the outlet opening 22 of the shroud 20 to the recirculation channel P1, and also reduces the pressure loss of the flow of the primary heat transfer medium M1 from the outlet opening 22 to the direct channel P2 compared to the recirculation channel P1.

[0050] Furthermore, according to this embodiment, the outlet duct 50 includes a second partition plate 52 that separates the flow path of the primary heat transfer medium M1 from the recirculation flow path P1 to the outlet nozzle 14 from the direct flow path P2. This allows the primary heat transfer medium M1 from the recirculation flow path P1 to be accelerated and its static pressure reduced, and the flow of the primary heat transfer medium M1 from the direct flow path P2 to be merged. As a result, the pressure drop in the flow of the primary heat transfer medium M1 from the recirculation flow path P1 can be compensated for, and the flow of the primary heat transfer medium M1 from the outlet opening 22 of the shroud 20 toward the recirculation flow path P1 can be ensured.

[0051] Furthermore, according to this embodiment, the second partition plate 52 is inserted into the outlet nozzle 14. This allows the primary heat transfer medium M1 from the recirculating channel P1 and the primary heat transfer medium M1 from the direct channel P2 to be merged within the outlet nozzle 14. As a result, the primary heat transfer medium M1 from the recirculating channel P1 and the primary heat transfer medium M1 from the direct channel P2 can be merged even more easily. This compensates for the pressure drop in the flow of the primary heat transfer medium M1 from the recirculating channel P1 and promotes the flow of the primary heat transfer medium M1 from the outlet opening 22 of the shroud 20 toward the recirculating channel P1.

[0052] Furthermore, according to this embodiment, the second partition plate 52 includes a throttling region 53 that narrows the cross-sectional area of ​​the direct flow path P2, and an outlet region 54 that increases the flow velocity of the primary heat transfer medium M1 in the direct flow path P2. This increases the flow velocity of the primary heat transfer medium M1 that reaches the outlet region 54, thereby reducing the static pressure of the primary heat transfer medium M1. As a result, the flow of the primary heat transfer medium M1 from the recirculating flow path P1 can be easily merged with the flow of the primary heat transfer medium M1 from the direct flow path P2. This compensates for the pressure drop in the flow of the primary heat transfer medium M1 from the recirculating flow path P1, and promotes the flow of the primary heat transfer medium M1 from the outlet opening 22 of the shroud 20 toward the recirculating flow path P1.

[0053] Furthermore, according to this embodiment, the throttling region 53 is formed to approach the first partition plate 51 as it moves from the outlet opening 22 towards the outlet nozzle 14. This makes it possible to narrow the cross-sectional area of ​​the direct flow path P2 by a constant rate, thereby suppressing an increase in the pressure loss of the primary heat transfer medium M1 in the direct flow path P2.

[0054] Furthermore, according to this embodiment, the outlet region 54 extends in the axial direction 14D of the outlet nozzle 14. This allows the pressure of the flow of the primary heat transfer medium M1, which is restricted in the throttling region 53, to be reduced in the outlet region 54. As a result, the static pressure of the flow of the primary heat transfer medium M1 in the outlet region 54 can be effectively reduced, and the flow of the primary heat transfer medium M1 from the recirculation channel P1 can be easily merged with the flow of the primary heat transfer medium M1 from the direct channel P2.

[0055] Furthermore, according to this embodiment, the ratio of the flow area of ​​the portion of the flow path cross-section of the outlet nozzle 14 that directly constitutes the flow path P2 is smaller than the ratio of the flow area of ​​the portion of the flow path cross-section of the outlet opening 22 that directly communicates with the flow path P2. As a result, the flow velocity of the primary heat transfer medium M1 that is restricted in the throttling region 53 can be effectively increased in the outlet region 54, and the static pressure of the primary heat transfer medium M1 can be effectively reduced.

[0056] Furthermore, according to this embodiment, the shroud 20 includes a curved wall 23 positioned between the inlet opening 21 and the outlet opening 22, facing the main body 10. This suppresses fluctuations in the flow path cross-sectional area of ​​the recirculation channel P1, preventing an increase in pressure loss in the flow of the primary heat transfer medium M1. As a result, the flow of the primary heat transfer medium M1 in the recirculation channel P1 can be made smooth.

[0057] Furthermore, according to this embodiment, when viewed in a cross-section perpendicular to the axial direction 10D of the main body 10, the heat transfer tube group 30 is formed to follow the curved wall 23. This reduces the gap between the curved wall 23 and the heat transfer tube group 30, thereby improving the efficiency of heat exchange between the primary heat transfer medium M1 and the secondary heat transfer medium M2.

[0058] In the embodiment described above, an example was described in which the heat exchanger 1 is a bonnet-type heat exchanger in which the main body casing 10 includes a bonnet portion 15. However, this embodiment is not limited to this. For example, the heat exchanger 1 may be a header-type heat exchanger. In this case, in the heat exchanger 1, the secondary heat transfer medium M2 that flows into the inlet 15a is supplied directly to the heat transfer tubes 31 of the heat transfer tube group 30, and the secondary heat transfer medium M2 is discharged directly from the heat transfer tubes 31 to the outlet 15b.

[0059] Furthermore, in the above-described embodiment, an example was given in which the outlet region 54 of the outlet duct 50 extends along the axial direction 14D of the outlet nozzle 14. However, this embodiment is not limited to this. The shape of the outlet region 54 is arbitrary as long as it can increase the flow velocity of the primary heat transfer medium M1 in the direct flow path P2.

[0060] (Second Embodiment) Next, the heat exchanger in the second embodiment will be described using Figures 8 to 11.

[0061] In the second embodiment shown in Figures 8 to 11, the main difference is that the shroud includes a side wall extending axially from the outlet nozzle, positioned between the inlet and outlet openings. Other configurations are substantially the same as those of the first embodiment shown in Figures 1 to 7. In Figures 8 to 11, the same reference numerals are used for parts identical to those in the first embodiment shown in Figures 1 to 7, and detailed descriptions are omitted.

[0062] As shown in Figures 8 and 9, the shroud 20 according to this embodiment includes a side wall 24 positioned between the inlet opening 21 and the outlet opening 22, extending in the axial direction 14D of the outlet nozzle 14. A recirculation channel P1 is defined between the side wall 24 and the body 11 of the main body 10.

[0063] Multiple heat transfer tube groups 30 may be arranged within the shroud 20. Each heat transfer tube group 30 may be formed in a rectangular shape when viewed in a cross section perpendicular to the axial direction 10D of the main body shell 10. More specifically, the heat transfer tubes 31 constituting each heat transfer tube group 30 may be arranged in a rectangular shape. The heat transfer tube groups 30 may be arranged with spacing between them in the direction from the inlet opening 21 to the outlet opening 22.

[0064] Here, a typical heat exchanger 1 as shown in Figure 10 will be described. In the heat exchanger 1 shown in Figure 10, there is no inlet duct 40 and no outlet duct 50. The main body 10 and the shroud 20 are connected by a short-circuit prevention plate 60. The short-circuit prevention plate 60 is configured to prevent the primary heat transfer medium M1 that has flowed into the inlet nozzle 13 from flowing around the shroud 20. The short-circuit prevention plate 60 is formed on the side of the inlet nozzle 13 and also on the side of the outlet nozzle 14. This prevents the primary heat transfer medium M1 from flowing into the space between the side wall 24 of the shroud 20 and the main body 10.

[0065] Therefore, even in the typical heat exchanger 1 shown in Figure 10, the temperature of the main body 10 is higher near the inlet nozzle 13 and lower near the outlet nozzle 14. As a result, a temperature difference occurs in the main body 10, and this temperature difference can increase.

[0066] In contrast, according to this embodiment, the outlet duct 50 that defines the direct flow path P2 of the primary heat transfer medium M1 from the outlet opening 22 to the outlet nozzle 14 includes a first partition plate 51. The first partition plate 51 divides the flow of the primary heat transfer medium M1 from the outlet opening 22 into a recirculation flow path P1 and a direct flow path P2. As a result, even if the side wall 24 of the shroud 20 extends in the axial direction 14D of the outlet nozzle 14, the flow of the primary heat transfer medium M1 flowing out from the outlet opening 22 can be divided into a flow to the recirculation flow path P1 and a flow to the direct flow path P2. Therefore, the primary heat transfer medium M1 that has undergone heat exchange can flow into the recirculation flow path P1, and the temperature of the main body 10 near the inlet nozzle 13 can be reduced. As a result, the temperature difference of the main body 10 can be reduced.

[0067] As shown in Figure 11, a flow path defining portion 25 that defines the recirculation flow path P1 may be formed on the side wall 24 of the shroud 20. The flow path defining portion 25 may include a curved surface 25a facing the main body 10. This suppresses fluctuations in the flow path cross-sectional area of ​​the recirculation flow path P1 and prevents an increase in pressure loss in the flow of the primary heat transfer medium M1. As a result, the flow in the recirculation flow path P1 can be made smooth.

[0068] As shown in Figure 11, the flow path delimiting section 25 may include an insulating material 26. This suppresses the primary heat transfer medium M1 flowing through the recirculating flow path P1 from receiving heat from the primary heat transfer medium M1 flowing inside the shroud 20. Therefore, it is possible to suppress the temperature rise of the primary heat transfer medium M1 flowing through the recirculating flow path P1 and effectively lower the temperature of the main body 10. When the flow path delimiting section 25 includes an insulating material 26, as shown in Figure 11, the flow path delimiting section 25 may include a housing space 25b, and the housing space 25b may be filled with the insulating material 26.

[0069] According to the embodiments described above, the temperature difference of the main body 10 can be reduced.

[0070] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. Naturally, these embodiments can also be combined in part as appropriate within the scope of the spirit of the invention. [Explanation of Symbols]

[0071] 1: Heat exchanger, 10: Main body, 10D: Axial direction, 13: Inlet nozzle, 14: Outlet nozzle, 14D: Axial direction, 20: Shroud, 21: Inlet opening, 22: Outlet opening, 23: Curved wall, 24: Side wall, 25: Flow path definition section, 25a: Curved surface, 26: Insulation material, 30: Heat transfer tube group, 40: Inlet duct, 50: Outlet duct, 51: First partition plate, 52: Second partition plate, 53: Restriction area, 54: Outlet area, P1: Recirculation flow path, P2: Direct flow path, M1: Primary heat transfer medium, M2: Secondary heat transfer medium

Claims

1. A main body including an inlet nozzle into which the primary heat transfer medium flows, and an outlet nozzle into which the primary heat transfer medium flows out, A shroud housed within the main body, comprising an inlet opening through which the primary heat transfer medium flows in and an outlet opening through which the primary heat transfer medium flows out, wherein a recirculation path is defined between the main body and the shroud, communicating with a part of the outlet opening and communicating with the outlet nozzle. A heat exchange element disposed within the shroud, comprising a heat exchange element that exchanges heat between a secondary heat transfer medium flowing inside and the primary heat transfer medium, An inlet duct that defines the flow path of the primary heat transfer medium from the inlet nozzle to the inlet opening, An outlet duct that defines the direct flow path of the primary heat transfer medium from the outlet opening to the outlet nozzle, Equipped with, The outlet duct includes a first partition plate that divides the flow of the primary heat transfer medium from the outlet opening into the recirculation channel and the direct channel. heat exchanger.

2. The first partition plate extends in the axial direction of the outlet nozzle. The heat exchanger according to claim 1.

3. The outlet duct includes a second partition plate that separates the flow path of the primary heat transfer medium from the recirculation flow path to the outlet nozzle from the direct flow path. The heat exchanger according to claim 1.

4. The second partition plate is inserted into the outlet nozzle. The heat exchanger according to claim 3.

5. The direct flow path is defined between the first partition plate and the second partition plate. The second partition plate includes a throttling region extending from the shroud that narrows the cross-sectional area of ​​the direct flow path, and an outlet region extending from the throttling region to the outlet nozzle that increases the flow velocity of the primary heat transfer medium in the direct flow path. The heat exchanger according to claim 3 or 4.

6. The throttling region is formed so that it approaches the first partition plate as it moves from the outlet opening towards the outlet nozzle. The heat exchanger according to claim 5.

7. The aforementioned outlet region extends in the axial direction of the outlet nozzle. The heat exchanger according to claim 5.

8. The ratio of the flow path cross-sectional area of ​​the portion of the flow path cross-section of the outlet nozzle that constitutes the direct flow path is smaller than the ratio of the flow path cross-sectional area of ​​the portion of the flow path cross-section of the outlet opening that communicates with the direct flow path. The heat exchanger according to claim 5.

9. The shroud includes a curved wall positioned between the inlet opening and the outlet opening, facing the main body. A heat exchanger according to claim 1 or 2.

10. When viewed in a cross-section perpendicular to the axial direction of the main body, the heat exchange element is formed to follow the curved wall. The heat exchanger according to claim 9.

11. The shroud includes a side wall that extends axially to the outlet nozzle and is positioned between the inlet opening and the outlet opening. A heat exchanger according to claim 1 or 2.

12. A channel defining portion that defines the recirculation channel is formed on the side wall of the shroud. The flow path defining portion includes a curved surface facing the main body, The heat exchanger according to claim 10.

13. The channel definition portion includes an insulating material. The heat exchanger according to claim 12.

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