Fin structure and heat exchanger

Abstract

This application discloses a fin structure and a heat exchanger. The fin structure includes a fin base, which is a corrugated fin and has tube holes for heat exchange tubes to pass through, and a plurality of protrusions disposed on the fin base and surrounding the outer periphery of the tube holes. The fin structure and heat exchanger according to this application can effectively improve the heat exchange effect of the fins and enhance the heat exchange performance of the heat exchanger.

Description

Technical Field

[0001] This application relates to the technical field of refrigeration devices, and more particularly to fin structures and heat exchangers.

Background Art

[0002] In the prior art, finned-tube heat exchangers are widely used in chemical, ventilation, heating, air conditioning, refrigeration, and other industries due to characteristics such as easy manufacturing and high applicability. Methods for maximizing heat transfer and utilizing thermal energy (enhancement of heat transfer) have always been the focus of industry research.

[0003] The fin structures of finned-tube heat exchangers mainly include straight fins, corrugated fins, and corresponding slotted (windowed) structures. In the case of conventional straight fins and corrugated fins, heat exchange is often insufficient on the leeward side of the heat exchange tubes. The corresponding slotted structure increases the contact area on the air side, while the structural irregularity disturbs the flow field, which promotes the mixing between fluids, delays the separation of the boundary layer flow, and thereby improves the overall heat exchange performance. However, the slotted structure usually reduces the flow gap and increases the flow resistance of the fins. Therefore, the fins are easily blocked by frost under wet conditions, shortening the life of the fins and at the same time reducing the effective heat exchange area, which affects the actual heat exchange effect of the fins. Considering resistance, heat transfer performance, and processability comprehensively, corrugated fins are a more suitable shape for industrial applications. However, due to the further improvement of the requirements regarding heat dissipation of heat exchangers, it is difficult for conventional corrugated fins to meet the performance requirements of high-efficiency heat exchangers.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Embodiments of this application provide a fin structure and a heat exchanger that improve the heat exchange effect of fins and enhance the heat exchange performance of the heat exchanger.

Means for Solving the Problem

[0005] To achieve the above object, the present application provides a fin base which is a corrugated fin and has a tube hole through which a heat exchange tube penetrates, and a plurality of convex portions disposed on the fin base and surrounding the outer periphery of the tube hole. A fin structure is provided.

[0006] Furthermore, the fin base includes a plurality of first plates and a plurality of second plates. The second plates are connected between two first plates, and the length L1 of the corresponding section of the first plate is larger than the length L2 of the corresponding section of the second plate.

[0007] Furthermore, there are two second plates between two first plates, and the two second plates are arranged adjacent to each other.

[0008] Also, the ratio h1 / S of the corrugation height h1 of the fin base to the fin pitch S is 0.58 to 0.62, and L1 / L2 is 1.5 to 1.7.

[0009] Also, the plurality of convex portions include an annular convex portion convexly disposed on the first plate and a lateral convex portion convexly disposed on the second plate.

[0010] Also, the annular convex portion is an annular convex structure, a plurality of annular convex portions are arranged, and the plurality of annular convex portions are symmetrically distributed on the outer periphery of the tube hole.

[0011] Also, the lateral convex portion is a boss, a plurality of lateral convex portions are arranged, and the plurality of lateral convex portions are symmetrically distributed on the outer periphery of the tube hole.

[0012] Also, the ratio h3 / S of the raised height h3 of the annular convex portion to the fin pitch S is 0.35 to 0.4.

[0013] Also, the ratio h2 / S of the raised height h2 of the lateral convex portion to the fin pitch S is 0.35 to 0.4.

[0014] Furthermore, the fin base is provided with an annular groove, the tube hole is located within the annular groove, the annular groove and the tube hole are arranged concentrically, the outer periphery of the annular groove is connected to the first plate and the second plate, and all the convex portions are located outside the annular groove.

[0015] Furthermore, there are two second plates between the two first plates, the two second plates are arranged adjacent to each other, a wave trough line where the two second plates intersect is formed, two arc surfaces symmetrical to the tube hole are formed at the joint between the annular groove and the two first plates, and four plane surfaces symmetrical to the tube hole are formed at the joint between the annular groove and the two second plates.

[0016] Furthermore, the bottom of the annular groove is in contact with the wave trough line in the vertical inflow direction, and the included angle θ between the generatrix of the arc surface and the central axis of the heat exchange tube is 45°.

[0017] Also, the ratio d1 / D of the diameter d1 of the bottom of the annular groove to the outer diameter D of the heat exchange tube is 1.6 - 1.7.

[0018] Also, the two first plates are arranged symmetrically with respect to the tube hole, and the two second plates are arranged symmetrically with respect to the tube hole.

[0019] Also, the ratio D1 / D of the inner diameter D1 of the tube hole to the outer diameter D of the heat exchange tube is 1.025 - 1.035.

[0020] According to another aspect of the present application, a heat exchanger including the above fin structure is provided.

[0021] In this application, the structure of the corrugated fin is improved by arranging a plurality of convex portions on the outer periphery of the tube holes. The convex portions play a role in strengthening the turbulence of the air flow near the tube holes (installed heat exchanger), thereby increasing the flow velocity in the local area, enhancing the mixing of the cold and warm fluids, increasing the effective heat exchange area of the fin, and thereby improving the heat exchange performance of the heat exchanger. The fin structure according to this application is less likely to be frosted on the fin surface under wet conditions compared to the fin with a window, thereby effectively reducing the occurrence of flow path blockage. Compared with the ordinary corrugated fin, the fin structure according to this application effectively increases the heat exchange area, thereby further improving the heat exchange effect.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0023] This application will be described in more detail below in combination with the accompanying drawings and specific embodiments, which are not intended to limit this application.

[0024] Referring to FIGS. 1 to 4, according to an embodiment of the present application, a fin structure is provided. The fin structure includes a fin base 10 and a plurality of convex portions 30 and. The fin base 10 is provided with a tube hole 20 through which a heat exchange tube penetrates, and the fin base 10 is a corrugated fin. The convex portions are arranged on the fin base 10, and the plurality of convex portions 30 surround the outer periphery of the tube hole 20.

[0025] In the present application, by arranging a plurality of convex portions 30 on the outer periphery of the tube hole, the structure of the corrugated fin is improved. The convex portion 30 serves to strengthen the turbulence of the air flow near the tube hole (installed heat exchanger), thereby increasing the flow velocity in a local area, enhancing the mixing of the cold and warm fluids, increasing the effective heat exchange area of the fins, and thereby improving the heat exchange performance of the heat exchanger. The fin structure according to the present application is less likely to be frosted on the fin surface under a wet condition compared to a fin with a window, thereby effectively reducing the occurrence of flow path blockage. Compared with a normal corrugated fin, the fin structure according to the present application effectively increases the heat exchange area, thereby further improving the heat exchange effect.

[0026] In combination with FIGS. 1 and 2, the fin base 10 includes a plurality of first plates 11 and a plurality of second plates 12. The second plates 12 are connected between two first plates 11, and the length L1 of the corresponding section of the first plate 11 is greater than the length L2 of the corresponding section of the second plate 12. That is, the surface of the fin base 10 is divided into large plates and small plates, which become the first plate and the second plate respectively, and spreads in an M shape along the air flow direction. As used herein, "a plurality" means two or more.

[0027] There are two second plates 12 between two first plates 11, and the two second plates 12 are arranged adjacent to each other. In some embodiments, the two first plates 11 are arranged symmetrically with respect to the tube hole 20, the two second plates 12 are arranged symmetrically with respect to the tube hole 20, and the trough line of the wave where the two second plates 12 intersect on it 13 is formed. Due to such a structural arrangement of the first plate 11 and the second plate 12 in this embodiment, the entire fin surface spreads in an M shape along the air flow direction.

[0028] In some embodiments, the ratio h1 / S of the waveform height h1 of the fin base 10 to the fin pitch S is 0.58 - 0.62, and L1 / L2 is 1.5 - 1.7. Based on such a relationship between the waveform height and the fin pitch, and such a relationship between the corresponding section length L1 of the first plate 11 and the corresponding section length L2 of the second plate 12, the heat exchange capacity of the fin itself is improved.

[0029] Referring to FIG. 2, the plurality of convex portions 30 include an annular convex portion 31 and a transverse convex portion 32. The annular convex portion 31 is convexly arranged on the first plate 11, and the transverse convex portion 32 is convexly arranged on the second plate 12. Both the annular convex portion 31 and the lateral convex portion 32 enhance the fluid turbulence, are arranged on different plates, thereby delaying the separation phenomenon of the boundary layer flow and improving the heat exchange performance of the fin.

[0030] The annular convex portion 31 is an annular convex structure, and a plurality of annular convex portions 31 are arranged. The plurality of annular convex portions 31 are symmetrically distributed on the outer periphery of the tube hole 20. In this embodiment, the plurality of annular convex portions 31 are four annular convex segment symmetrically arranged on the first plate 11.

[0031] The transverse convex portion 32 is a boss, and a plurality of transverse convex portions 32 are arranged. The plurality of transverse convex portions 32 are symmetrically distributed around the outer periphery of the tube hole 20. The plurality of transverse convex portions 32 are four segments of square bosses symmetrically arranged on the second plate 12. The transverse convex portion 32 has the shape of a rectangular block. Due to the arrangement of the transverse convex portion 32 and the annular convex portion 31, the turbulence of the air flow near the heat exchange tube is enhanced, so the flow velocity in the local area is improved, the mixing of the warm and cold fluids is promoted, and the thickness of the boundary layer is reduced, whereby the wake region behind the tube is significantly reduced, and the effective heat exchange area of the fin is increased.

[0032] In order to consider the balanced relationship between the air flow and the height of the annular convex portion 31, the ratio h3 / S of the raised height h3 of the annular convex portion 31 to the fin pitch S is 0.35 to 0.4.

[0033] In order to consider the balanced relationship between the air flow and the height of the transverse convex portion 32, the ratio h2 / S of the raised height h2 of the transverse convex portion 32 to the fin pitch S is 0.35 to 0.4.

[0034] In some embodiments, the fin base 10 is provided with an annular groove 40. The tube hole 20 is located within the annular groove 40. The annular groove 40 and the tube hole 20 are arranged concentrically. The outer periphery of the annular groove 40 is connected to the first plate 11 and the second plate 12, and the convex portions 30 are all located outside the annular groove 40. The structural arrangement of the annular groove 40 is convenient for the punching and forming of the peripheral transverse convex portions 32 and the annular convex portion 31, and improves the practicality of the process. Due to the structure of the annular groove 40, the processing difficulty is simplified, the processing cost of the fin structure is reduced, and a very high industrial value is achieved.

[0035] There are two second plates 12 between the two first plates 11. The two second plates 12 are arranged adjacent to each other, and the trough lines of the waves where the two second plates 12 intersect above 13 are formed. An arc surface 41 is formed at the joint of the annular groove 40 and each first plate 11. Two flat surfaces 42is formed. The two arc surfaces formed at the joint between the annular groove 40 and the two first plates 11 are symmetric with respect to the tube hole 20. The four flat surfaces 42 formed at the joint between the annular groove 40 and the two second plates 12 are symmetric with respect to the tube hole 20. The bottom of the annular groove 40 43 is a circular surface and is in contact with the trough line of the wave in the vertical inflow direction. 13 The included angle θ between the generatrix of the arc surface 41 and the central axis of the heat exchange tube is 45°.

[0036] The ratio d1 / D of the diameter d1 of the bottom of the annular groove 40 to the outer diameter D of the heat exchange tube is 1.6 - 1.7. The ratio D1 / D of the inner diameter D1 of the tube hole 20 to the outer diameter D of the heat exchange tube is 1.025 - 1.035.

[0037] This application also provides an embodiment of a heat exchanger, and the heat exchanger includes the fin structure of the above embodiment.

[0038] This embodiment is verified by ANSYS fluid simulation. During the simulation, the inflow air flow rates are 2 m / s, 3 m / s, 4 m / s, 5 m / s, and 6 m / s respectively, the air inflow temperature is 35°C, the tube wall temperature is 50.62°C, and the heat exchange amount Q, Nusselt number Nu, and thermal resistance R, as well as the change situation of the flow field characteristics, in the flow paths before and after the transverse convex part 32 and the annular convex part 31 are arranged in the same flow are compared. Here, the heat exchange amount Q, Nusselt number Nu, and thermal resistance R are defined as follows.

Number

Number

Number

Number

Number

Number

[0039] The heat exchange quantity Q, Nusselt number Nu, and thermal resistance R can all be calculated by extracting simulation data. The larger the heat exchange quantity Q and Nusselt number Nu, or the smaller the thermal resistance R, the better the heat exchange performance.

[0040] Figure 5 shows the change situation of the heat exchange quantity Q with the inflow air velocity. The greater the inflow air velocity, the more improved the increase in the heat exchange quantity. At 6 m / s, the increase in the heat exchange quantity is the largest compared to the original fin, which is 4.37%. The new fin in Figure 5 refers to the fin structure according to this application, and the original fin refers to the fin structure of the prior art.

[0041] Figure 6 shows the change in the Nusselt number Nu with the inlet air velocity. As the inlet air velocity increases, the Nusselt number gradually increases. At 2 m / s, the increase in the Nusselt number is the largest compared to the original fin, which is 11.16%. The new fin in Figure 6 refers to the fin structure according to this application, and the original fin refers to the fin structure of the prior art.

[0042] Figure 7 shows the change in the thermal resistance R with the inlet air velocity. As the inlet air velocity increases, the thermal resistance gradually decreases. At 2 m / s, the decrease in the thermal resistance is the largest compared to the original fin, which is 14.52%. The new fin in Figure 7 refers to the fin structure according to this application, and the original fin refers to the fin structure of the prior art.

[0043] This application also provides a comparison of the flow field characteristics in the flow path before and after the arrangement of the lateral convex portion 32 and the annular convex portion 31 when the inlet air velocity is 2 m / s, 4 m / s, and 6 m / s, as shown in Figures 8 to 10. Figure 8 is a diagram showing the comparison of the flow field characteristics in the flow path when the inlet air velocity is 2 m / s, Figure 9 is a diagram showing the comparison of the flow field characteristics in the flow path when the inlet air velocity is 4 m / s, and Figure 10 is a diagram showing the comparison of the flow field characteristics in the flow path when the inlet air velocity is 6 m / s.

[0044] At different inlet air velocities, the comparison between the fin structure of the prior art and the fin structure of this application shows the same difference in the flow field characteristics. This is mainly due to the arrangement of the lateral convex portion 32 and the annular convex portion 31, which strengthens the turbulence of the air flow near the heat exchange tube, increases the flow velocity in the local area, promotes the mixing of the cold fluid, reduces the thickness of the boundary layer, which greatly reduces the wake region behind the tube, increases the effective heat exchange area of the fin, and thereby reflects the improvement of the heat exchange performance of the heat exchanger.

[0045] It should be noted that the terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments of this application. When used in this specification, the singular form is intended to include the plural form unless the context clearly indicates otherwise. Also, when the terms "containing" and / or "including" are used in the description, it should be understood that they also indicate the presence of a composition, step, operation, device, component, and / or a combination thereof.

[0046] It should be noted that the terms such as "first", "second", etc. in the specification, claims, and the above drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. Since the data used in this way can be exchanged under appropriate circumstances, it should be understood that the embodiments of this application described in this specification can be implemented in an order other than those illustrated or described in this specification.

[0047] Of course, the above are the preferred embodiments of this application. It should be pointed out that those skilled in the art can also make some improvements and modifications without departing from the basic principles of this application, and these improvements and modifications are also regarded as within the protection scope of this application.

Claims

1. A fin structure comprising a fin base (10) and a plurality of convex portions (30), wherein the fin base (10) is a corrugated fin and has a tube hole (20) for a heat exchange tube to penetrate therethrough, the plurality of convex portions (30) are disposed on the fin base (10) and surround the outer periphery of the tube hole (20), the fin base (10) comprises a plurality of first plates (11) and a plurality of second plates (12), the second plates (12) are connected between two first plates (11), and the length L1 of the corresponding section of the first plate (11) is greater than the length L2 of the corresponding section of the second plate (12), the plurality of convex portions (30) are annular sector-shaped convex portions (31) convexly disposed on the first plate (11), the annular sector-shaped convex portions (31) are annular sector-shaped convex structures, a plurality of the annular sector-shaped convex portions (31) are arranged, and the plurality of annular sector-shaped convex portions (31) are symmetrically distributed with respect to the outer periphery of the tube hole (20), the annular sector-shaped convex portions (31), and transverse convex portions (32) convexly disposed on the second plate (12), the transverse convex portions (32) are bosses, a plurality of the transverse convex portions (32) are arranged, and the plurality of transverse convex portions (32) are symmetrically distributed with respect to the outer periphery of the tube hole (20), the transverse convex portions (32), comprising, a fin structure.

2. There are two second plates (12) between two first plates (11), and the two second plates (12) are adjacently arranged. The fin structure according to Claim 1.

3. The fin base (10) comprises an annular groove (40), the tube hole (20) is located within the annular groove (40), the annular groove (40) and the tube hole (20) are concentrically arranged, the outer periphery of the annular groove (40) is connected to the first plate (11) and the second plate (12), and all of the convex portions (30) are located outside the annular groove (40). The fin structure according to Claim 1.

4. There are two second plates (12) between two first plates (11), the two second plates (12) are adjacently arranged, and a valley line (13) of intersecting waves is formed by the two second plates (12), At the joint between the annular groove (40) and the two first plates (11), two arc surfaces (41) symmetrical with respect to the tube hole (20) are formed, and four plane surfaces (42) symmetrical with respect to the tube hole (20) are formed at the joint between the annular groove (40) and the two second plates (12). The fin structure according to claim 3.

5. The two first plates (11) are arranged symmetrically with respect to the tube hole (20), and the two second plates (12) are arranged symmetrically with respect to the tube hole (20). The fin structure according to claim 2.

6. A heat exchanger comprising the fin structure according to claim 1.

7. Comprising a plurality of the fin structures, For the heat exchanger according to claim 6, the ratio h1 / S of the corrugation height h1 of the fin base (10) to the fin pitch S is 0.58 to 0.62, and L1 / L2 is 1.5 to 1.

7.

8. For the heat exchanger according to claim 7, the ratio h3 / S of the raised height h3 of the annular sector convex part (31) to the fin pitch S is 0.35 to 0.

4.

9. For the heat exchanger according to claim 8, the ratio h2 / S of the raised height h2 of the lateral convex part (32) to the fin pitch S is 0.35 to 0.

4.

10. The heat exchanger includes a heat exchange tube passing through the tube hole (20), The fin base (10) includes an annular groove (40), The tube hole (20) is located within the annular groove (40), The annular groove (40) and the tube hole (20) are arranged concentrically, The outer periphery of the annular groove (40) is connected to the first plate (11) and the second plate (12), All the convex parts (30) are located outside the annular groove (40), The two second plates (12) are between the two first plates (11), The two second plates (12) are arranged adjacent to each other, A valley line (13) of intersecting waves is formed between the two second plates (12), At the joint between the annular groove (40) and the two first plates (11), two arc surfaces (41) symmetrical with respect to the tube hole (20) are formed, and four plane surfaces (42) symmetrical with respect to the tube hole (20) are formed at the joint between the annular groove (40) and the two second plates (12). The groove bottom (43) of the annular groove (40) is in contact with the valley line (13) in the vertical inflow direction. The heat exchanger according to claim 6, wherein the included angle θ between the generatrix of the arc surface (41) and the central axis of the heat exchange tube is 45°. **Claim 11**: The heat exchanger includes a heat exchange tube passing through the tube hole (20). The fin base (10) is provided with an annular groove (40). The tube hole (20) is located within the annular groove (40). The annular groove (40) and the tube hole (20) are arranged concentrically. The outer periphery of the annular groove (40) is connected to the first plate (11) and the second plate (12). All of the convex portions (30) are located outside the annular groove (40). The heat exchanger according to claim 6, wherein the ratio d1 / D of the diameter d1 of the groove bottom (43) of the annular groove (40) to the outer diameter D of the heat exchange tube is 1.6 to 1.

7. **Claim 12**: The heat exchanger includes a heat exchange tube passing through the tube hole (20). The heat exchanger according to claim 6, wherein the ratio D1 / D of the inner diameter D1 of the tube hole (20) to the outer diameter D of the heat exchange tube is 1.025 to 1.035.

Images