Heat exchanger

Abstract

To avoid generation of a gas-liquid interface between a flow passage structure and a shell.SOLUTION: A heat exchanger 1 includes: a flow passage structure 2 partitioned by a partition wall 4 along a triple cycle minimal curved surface and having a first flow passage 5 in which first fluid Fa flows and a second flow passage 6 in which second fluid Fb flows; and a shell 3 covering the flow passage structure 2. A first portion 5A of the first flow passage 5 is provided between an inner surface 3A of the shell 3 and the flow passage structure 2 disposed at a position separate from the inner surface 3A of the shell 3.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The technology disclosed in this specification relates to a heat exchanger.

Background Art

[0002] In the technical field related to heat exchangers, a heat exchanger having a triply periodic minimal surface (TPMS) structure as disclosed in Patent Document 1 is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a heat exchanger including a flow path structure having a triply periodic minimal surface flow path structure, if a gas-liquid interface occurs between the flow path structure and a shell covering the flow path structure, it may lead to damage due to liquid concentration or local overheating.

[0005] The technology disclosed in this specification aims to avoid the occurrence of a gas-liquid interface between the flow path structure and the shell.

Means for Solving the Problems

[0006] This specification discloses a heat exchanger. The heat exchanger includes a flow path structure having a first flow path through which a first fluid flows and a second flow path through which a second fluid flows, the first flow path and the second flow path being separated by a partition along a triply periodic minimal surface, and a shell covering the flow path structure. A first portion of the first flow path is provided between the inner surface of the shell and the flow path structure disposed at a position away from the inner surface of the shell.

Effects of the Invention

[0007] According to the technology disclosed in this specification, the occurrence of a gas-liquid interface between the flow path structure and the shell is avoided.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0009] [First Embodiment] Hereinafter, the first embodiment will be described with reference to the drawings. In the first embodiment, a three-dimensional orthogonal coordinate system is set, and the positional relationship of each part will be described with reference to the three-dimensional orthogonal coordinate system. The direction parallel to the X-axis in the horizontal plane is defined as the X-axis direction. The direction parallel to the Y-axis orthogonal to the X-axis in the horizontal plane is defined as the Y-axis direction. The direction parallel to the Z-axis orthogonal to each of the X-axis and the Y-axis is defined as the Z-axis direction.

[0010] FIG. 1 is a longitudinal sectional view showing a heat exchanger 1 according to the first embodiment. The heat exchanger 1 exchanges heat between a first fluid Fa and a second fluid Fb. In this embodiment, the first fluid Fa is a liquid such as tap water or groundwater, and the second fluid Fb is a gas such as combustion gas or compressed air. As shown in FIG. 1, the heat exchanger 1 includes a flow path structure 2 and a shell 3.

[0011] The shell 3 is arranged to cover the flow path structure 2. The shell 3 has a cylindrical portion 30, a first wall portion 31, and a second wall portion 32. The cylindrical portion 30 is long in the Z-axis direction. In the embodiment, the cylindrical portion 30 is cylindrical. The central axis of the cylindrical portion 30 is parallel to the Z-axis.

[0012] The first wall portion 31 is arranged to cover the end portion of the cylindrical portion 30 on the -Z direction side. The second wall portion 32 is arranged to cover the end portion of the cylindrical portion 30 on the +Z direction side. The first header 33 is defined by the first wall portion 31 and a part of the cylindrical portion 30 on the -Z direction side. The second header 34 is defined by the second wall portion 32 and a part of the cylindrical portion 30 on the +Z direction side.

[0013] The shell 3 has a first supply port 35, a first discharge port 36, a second supply port 37, and a second discharge port 38. The first supply port 35 is connected to the first header 33. The first discharge port 36 is connected to the periphery of the second wall portion 32 that communicates with the second header 34. The second supply port 37 is connected to the second wall portion 32. The second discharge port 38 is connected to the first wall portion 31. The first fluid Fa is supplied to the inside of the shell 3 through the first supply port 35. The first fluid Fa inside the shell 3 is discharged to the outside of the shell 3 through the first discharge port 36 after flowing through the flow path structure 2. The second fluid Fb is supplied to the inside of the flow path structure 2 through the second supply port 37. The second fluid Fb after flowing through the flow path structure 2 is discharged to the outside through the second discharge port 38.

[0014] The first supply port 35 protrudes from a part of the cylindrical portion 30 on the -Z direction side toward the +X direction side. The first supply port 35 is cylindrical. The central axis of the first supply port 35 is parallel to the X-axis.

[0015] The first discharge port 36 protrudes from the periphery of the second wall portion 32 toward the +Z direction side. The second discharge port 38 is cylindrical. The central axis of the first discharge port 36 intersects the Z-axis at a predetermined angle (for example, 30°).

[0016] The second supply port 37 protrudes from the second wall portion 32 toward the +Z direction side. The second supply port 37 is cylindrical. The central axis of the second supply port 37 is parallel to the Z axis. The central axis of the second supply port 37 coincides with the central axis of the cylindrical portion 30.

[0017] The second discharge port 38 protrudes from the first wall portion 31 toward the -Z direction side. The second discharge port 38 is cylindrical. The central axis of the second discharge port 38 is parallel to the Z axis. The central axis of the second discharge port 38 coincides with the central axis of the cylindrical portion 30.

[0018] The flow path structure 2 has a first flow path 5 through which a first fluid Fa flows and a second flow path 6 through which a second fluid Fb flows. The flow path structure 2 has a partition wall 4 that separates the first flow path 5 and the second flow path 6. The first fluid Fa flowing through the first flow path 5 and the second fluid Fb flowing through the second flow path 6 exchange heat through the partition wall 4.

[0019] The partition wall 4 is formed along a triply periodic minimal surface. A triply periodic minimal surface refers to a surface that has the minimum area among surfaces with a closed curve given in a three-dimensional space as a boundary. Examples of the triply periodic minimal surface include the gyroid surface (G-surface) of Schoen, Schwarz's D-surface, or Schoen's I-WP surface. In the embodiment, the partition wall 4 is formed along the gyroid surface.

[0020] The gyroid surface can be infinitely connected in three mutually different directions and is a minimal surface that divides the space into two regions. In the embodiment, the gyroid surface can be infinitely connected in the X-axis direction, Y-axis direction, and Z-axis direction, respectively.

[0021] The gyroid surface is a surface that has the minimum area under given boundary conditions and has a curvature of zero when integrated. The gyroid surface is represented by an approximate formula using the trigonometric functions shown in the following formula (1).

[0022] sin(X×P1)×cos(Y×P2)+sin(Y×P2)×cos(Z×P3)+sin(Z×P3)×cos(X×P1)=0 …(1)

[0023] (1) In the formula, X, Y, and Z are real numbers from -n to +n. P1, P2, and P3 are real numbers greater than 0. As shown in the formula (1), the gyroloid surface has a structure that is infinitely connected in each of the X-axis direction, Y-axis direction, and Z-axis direction. When each of P1, P2, and P3 is 1, the one-period in the X-axis direction, Y-axis direction, and Z-axis direction is 2n respectively. When each of P1 and P2 is 1 and P3 is 2, the one-period in the Z-axis direction is n, and it is half of the one-period in the X-axis direction and Y-axis direction.

[0024] The partition wall 4 is a wall centered on a virtual surface represented by the formula (1) and having a substantially uniform thickness in the normal direction of the surface. In the flow path structure 2, the total area of the inner surface (heat transfer surface) of the first flow path 5 and the total area of the inner surface (heat transfer surface) of the second flow path 6 are substantially equal.

[0025] The inlet 51 of the first flow path 5 is constituted by the first open end of the first flow path 5. The outlet 52 of the first flow path 5 is constituted by the second open end of the first flow path 5. The inlet 61 of the second flow path 6 is constituted by the first open end of the second flow path 6. The outlet 62 of the second flow path 6 is constituted by the second open end of the second flow path 6.

[0026] The flow path structure 2 includes a main body portion 7, a first rectifying portion 8, and a second rectifying portion 9.

[0027] The main body portion 7 is long in the Z-axis direction. The outer shape of the main body portion 7 is substantially cylindrical. The central axis of the main body portion 7 is parallel to the Z-axis. The outer surface of the main body portion 7 faces the inner surface of the cylindrical portion 30 with a gap therebetween. The main body portion 7 has a first end portion 7A on the -Z direction side and a second end portion 7B on the +Z direction side.

[0028] The first rectifying section 8 is arranged at the first end portion 7A of the main body section 7. The outer shape of the first rectifying section 8 becomes thinner as it moves away from the main body section 7. The outer shape of the first rectifying section 8 gradually becomes thinner toward the -Z direction side. The outer shape of the first rectifying section 8 is frustum-shaped. In the embodiment, the outer shape of the first rectifying section 8 is frustum of a cone-shaped. The central axis of the first rectifying section 8 is parallel to the Z axis.

[0029] The second rectifying section 9 is arranged at the second end portion 7B of the main body section 7. The outer shape of the second rectifying section 9 becomes thinner as it moves away from the main body section 7. The outer shape of the second rectifying section 9 gradually becomes thinner toward the +Z direction side. The outer shape of the second rectifying section 9 is frustum-shaped. In the embodiment, the outer shape of the second rectifying section 9 is frustum of a cone-shaped. The central axis of the second rectifying section 9 is parallel to the Z axis.

[0030] The thickness of the first end portion 7A and the thickness of the second end portion 7B are equal. The thickness of the main body section 7 is substantially constant in the Z-axis direction. The thickness of the first end portion 7A of the main body section 7 and the thickness of the end portion on the +Z direction side of the first rectifying section 8 connected to the first end portion 7A are equal. The thickness of the second end portion 7B of the main body section 7 and the thickness of the end portion on the -Z direction side of the second rectifying section 9 connected to the second end portion 7B are equal. Note that the thickness of the flow path structure 2 refers to the dimension in the radial direction with respect to the central axis of the cylindrical portion 30.

[0031] The outer shape and dimensions of the first rectifying section 8 and the outer shape and dimensions of the second rectifying section 9 are equal. The main body section 7, the first rectifying section 8, and the second rectifying section 9 are integrally formed (single member). The central axis of the main body section 7, the central axis of the first rectifying section 8, and the central axis of the second rectifying section 9 coincide. The flow path structure 2 is arranged inside the shell 3 such that the central axis of the flow path structure 2 coincides with the central axis of the cylindrical portion 30.

[0032] The first rectifying section 8 is arranged in the first header 33. The second rectifying section 9 is arranged in the second header 34.

[0033] The inlet 51 of the first flow path 5 is provided on the surface of the first rectifying section 8. The outlet 52 of the first flow path 5 is provided on the surface of the second rectifying section 9.

[0034] The inlet 61 of the second flow path 6 is provided on the surface of the second rectifying portion 9. The outlet 62 of the second flow path 6 is provided on the surface of the first rectifying portion 8.

[0035] In the first embodiment, the inlet 51 of the first flow path 5 is provided on the side surface 82 of the first rectifying portion 8. The outlet 52 of the first flow path 5 is provided on the side surface 92 of the second rectifying portion 9.

[0036] In the first embodiment, the inlet 61 of the second flow path 6 is provided on the top surface 91 of the second rectifying portion 9. The outlet 62 of the second flow path 6 is provided on the top surface 81 of the first rectifying portion 8.

[0037] The first supply port 35 is disposed at at least a part around the first rectifying portion 8. Specifically, the first supply port 35 is connected to a part on the -Z direction side of the cylindrical portion 30 where the first header 33 is defined. The first supply port 35 supplies the first fluid Fa to the first rectifying portion 8. The first supply port 35 communicates with the side surface 82 of the first rectifying portion 8. The first supply port 35 supplies the first fluid Fa to the side surface 82 of the first rectifying portion 8. That is, the first supply port 35 supplies the first fluid Fa to the inlet 51 of the first flow path 5. The first fluid Fa is supplied to the inlet 51 via the first supply port 35. The first fluid Fa from the first supply port 35 is not supplied to the outlet 62. The first fluid Fa flows into the first flow path 5 through the inlet 51. The first fluid Fa that has flowed into the inlet 51 flows through the first flow path 5. The first fluid Fa flows through the first flow path 5 toward the outlet 52 of the first flow path 5.

[0038] The first discharge port 36 is disposed at least partially around the second rectifying section 9. Specifically, the first discharge port 36 is connected to the periphery of the second wall portion 32 that communicates with a part on the +Z direction side of the cylindrical portion 30 where the second header 34 is defined. The first discharge port 36 discharges the first fluid Fa from the second rectifying section 9. The first discharge port 36 communicates with the side surface 92 of the second rectifying section 9. The first discharge port 36 discharges the first fluid Fa from the side surface 92 of the second rectifying section 9. That is, the first discharge port 36 discharges the first fluid Fa from the outlet 52 of the first flow path 5. The first fluid Fa flowing out from the outlet 52 is discharged to the outside of the shell 3 through the first discharge port 36.

[0039] The second supply port 37 is disposed at least partially around the second rectifying section 9. Specifically, the second supply port 37 is connected to the second wall portion 32. The second supply port 37 supplies the second fluid Fb to the second rectifying section 9. The second supply port 37 communicates with the top surface 91 of the second rectifying section 9. The second supply port 37 supplies the second fluid Fb to the top surface 91 of the second rectifying section 9. That is, the second supply port 37 supplies the second fluid Fb to the inlet 61 of the second flow path 6. The second fluid Fb is supplied to the inlet 61 through the second supply port 37. The second fluid Fb from the second supply port 37 is not supplied to the outlet 52. The second fluid Fb flows into the second flow path 6 through the inlet 61. The second fluid Fb flowing into the inlet 61 flows through the second flow path 6. The second fluid Fb flows through the second flow path 6 toward the outlet 62 of the second flow path 6.

[0040] The second discharge port 38 is disposed at least partially around the first rectifying section 8. Specifically, the second discharge port 38 is connected to the first wall portion 31. The second discharge port 38 discharges the second fluid Fb from the first rectifying section 8. The second discharge port 38 communicates with the top surface 81 of the first rectifying section 8. The second discharge port 38 discharges the second fluid Fb from the top surface 81 of the first rectifying section 8. That is, the second discharge port 38 discharges the second fluid Fb from the outlet 62 of the second flow path 6. The second fluid Fb flowing out from the outlet 62 is discharged to the outside of the shell 3 through the second discharge port 38.

[0041] The first fluid Fa flowing through the first flow path 5 and the second fluid Fb flowing through the second flow path 6 exchange heat in a countercurrent manner with each other via the partition wall 4. Note that since the liquid, which is the first fluid Fa, flows through the flow path structure 2 in an upward flow, even if dissolved gas is released from the liquid during the heat exchange process, bubbles are less likely to stay in the first flow path 5, and the bubbles are easily discharged together with the first fluid Fa. Further, since the gas, which is the second fluid Fb, flows through the flow path structure 2 in a downward flow, even if condensation occurs during the heat exchange process, drain is less likely to stay in the second flow path 6, and the drain is easily discharged together with the second fluid Fb.

[0042] FIG. 2 is an enlarged perspective view of a part of the flow path structure 2 according to the first embodiment. FIG. 3 is an enlarged perspective view of a part of the flow path structure 2 according to the first embodiment. FIG. 4 is an enlarged longitudinal sectional view of a part of the flow path structure 2 according to the first embodiment. FIG. 2 shows the flow path structure 2 in a state where the first fluid Fa and the second fluid Fb are not supplied. FIG. 3 shows the flow path structure 2 in a state where the first fluid Fa is supplied. FIG. 4 corresponds to the longitudinal sectional view of FIG. 3 and shows the flow path structure 2 in a state where the first fluid Fa is supplied.

[0043] As described above, in the first embodiment, the outer surface of the main body portion 7 faces the inner surface of the cylindrical portion 30 with a gap therebetween. The first portion 5A of the first flow path 5 is provided between the inner surface 3A of the cylindrical portion 30 of the shell 3 and the main body portion 7 of the flow path structure 2 disposed at a position away from the inner surface 3A of the cylindrical portion 30. The inner surface 3A of the cylindrical portion 30 faces the first portion 5A of the first flow path 5.

[0044] As shown in FIGS. 2 and 3, the partition wall 4 of the main body portion 7 facing the inner surface 3A of the cylindrical portion 30 is a closing wall 4A. The opening ends of the first flow path 5 and the second flow path 6 are not provided in the closing wall 4A. The closing wall 4A faces the first portion 5A of the first flow path 5.

[0045] The first portion 5A of the first flow path 5 and the second portion 6A of the second flow path 6 are provided so as to be adjacent to each other with the closing wall 4A therebetween. The surface facing the -X side of the closing wall 4A faces the first portion 5A of the first flow path 5. The surface facing the +X side of the closing wall 4A faces the second portion 6A of the second flow path 6.

[0046] As described above, the heat exchanger 1 includes a flow path structure 2 having a first flow path 5 through which a first fluid Fa flows and a second flow path 6 through which a second fluid Fb flows, the first and second flow paths being separated by a partition wall 4 along a triply periodic minimal surface, and a shell 3 covering the flow path structure 2. A first portion 5A of the first flow path 5 is provided between the inner surface 3A of the cylindrical portion 30 of the shell 3 and the main body portion 7 of the flow path structure 2 disposed at a position away from the inner surface 3A of the cylindrical portion 30.

[0047] According to the first embodiment, since the main body portion 7 faces the cylindrical portion 30 with a gap therebetween, and a first portion 5A, which is a part of the first flow path 5, is defined between the inner surface 3A of the cylindrical portion 30 and the main body portion 7, the generation of a gas-liquid interface between the flow path structure 2 and the shell 3 is avoided.

[0048] Further, according to the first embodiment, the partition wall 4 of the flow path structure 2 facing the inner surface 3A of the cylindrical portion 30 of the shell 3 is a closing wall 4A. A first portion 5A, which is a part of the first flow path 5, and a second portion 6A, which is a part of the second flow path 6, are provided adjacent to each other with the closing wall 4A therebetween. Thereby, the generation of a gas-liquid interface between the flow path structure 2 and the shell 3 is avoided.

[0049] FIG. 5 is an enlarged perspective view of a part of the flow path structure 200 according to the comparative example. As shown in FIG. 5, if the partition wall 400 of the flow path structure 200 facing the shell 3 contacts the shell 3, or if the opening end 500 of the first flow path 5 is provided in the flow path structure 200 facing the inner surface 3A of the shell 3, an air pocket may occur in at least a part of the first flow path 5 defined by the inner surface 3A of the shell 3, and a gas-liquid interface LS may occur between the flow path structure 2 and the shell 3. When the first fluid Fa, which is a liquid, and the second fluid Fb exchange heat through the partition wall 400 in a state where an air pocket has occurred, a part of the partition wall 400 in contact with the air in the air pocket may be locally overheated. When a part of the partition wall 400 is locally overheated, if the first fluid Fa is water, corrosive components (e.g., chloride ions) or hardness components (e.g., calcium ions) dissolved in the first fluid Fa may be gradually concentrated, resulting in high-temperature corrosion on the partition wall 4 or scale adhesion to the partition wall 4. In addition, the flow path structure 2 may be damaged due to stress concentration caused by overheating of the partition wall 400.

[0050] According to the first embodiment, since the occurrence of a gas-liquid interface between the flow path structure 2 and the shell 3 is avoided, problems such as the occurrence of high-temperature corrosion, scale adhesion, and damage due to stress concentration are prevented.

[0051] [Second Embodiment] The second embodiment will be described. In the following description, the same reference numerals are given to the same or equivalent components as those in the above-described embodiment, and the description of those components is simplified or omitted.

[0052] FIG. 6 is a longitudinal sectional view showing the heat exchanger according to the second embodiment. In the second embodiment, the central axis of the cylindrical portion 30 is arranged along the X-axis. The first supply port 35 is connected to a part on the -X direction side of the cylindrical portion 30 where the first header 33 is defined and to the lower end portion of the cylindrical portion 30. The first discharge port 36 is connected to a part on the +X direction side of the cylindrical portion 30 where the second header 34 is defined and to the upper end portion of the cylindrical portion 30.

[0053] The first fluid Fa flowing through the first flow path 5 and the second fluid Fb flowing through the second flow path 6 exchange heat in a countercurrent manner through the partition wall 4. Note that since the liquid, which is the first fluid Fa, flows horizontally through the flow path structure 2 while accompanying an upward flow, even if dissolved gas is released from the liquid during the heat exchange process, bubbles are less likely to stay in the first flow path 5 and are easily discharged together with the first fluid Fa.

[0054] Also, when condensation of the second fluid Fb occurs during the heat exchange process, the center of the inlet 61 may be eccentrically positioned above the center of the second end portion 7B, and the center of the outlet 62 may be eccentrically positioned below the center of the first end portion 7A. By forming the first rectifying portion 8 and the second rectifying portion 9 in an eccentric cone shape and connecting the second supply port 37 and the second discharge port 38 to the respective apex surfaces 81, 91, it becomes easier to discharge the drain together with the second fluid Fb.

[0055] According to the second embodiment, similar to the first embodiment, the occurrence of a gas-liquid interface between the flow path structure 2 and the shell 3 is avoided, so problems such as the occurrence of high-temperature corrosion, the adhesion of scale, and damage due to stress concentration are prevented.

[0056] [Contribution to the Sustainable Development Goals (SDGs) led by the United Nations] The heat exchanger according to the present disclosure can contribute to the achievement of Goal 9, "Build the infrastructure for industry and innovation," of the SDGs (Sustainable Development Goals).

Explanation of Reference Numerals

[0057] 1…Heat exchanger, 2…Flow path structure, 3…Shell, 3A…Inner surface, 4…Partition wall, 4A…Blocking wall, 5…First flow path, 5A…First part, 6…Second flow path, 6A…Second part, 7…Main body part, 7A…First end part, 7B…Second end part, 8…First rectifying part, 9…Second rectifying part, 30…Cylindrical part, 31…First wall part, 32…Second wall part, 33…First header, 34…Second header, 35…First supply port, 36…First discharge port, 37…Second supply port, 38…Second discharge port, 51…Inlet, 52…Outlet, 61…Inlet, 62…Outlet, 81…Top surface, 82…Side surface, 91…Top surface, 92…Side surface, 200…Flow path structure, 400…Partition wall, 500…Open end, Fa…First fluid, Fb…Second fluid.

Claims

1. A flow path structure having a first flow path through which a first fluid flows and a second flow path through which a second fluid flows, separated by a partition along a triply periodic minimal surface, and a shell covering the flow path structure, wherein a first portion of the first flow path is provided between an inner surface of the shell and the flow path structure disposed at a position away from the inner surface of the shell, a heat exchanger.

2. The partition of the flow path structure facing the inner surface of the shell is a closing wall, and the first portion of the first flow path and the second portion of the second flow path are provided adjacent to each other with the closing wall therebetween, The heat exchanger according to claim 1.

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