A high-efficiency corrosion-resistant finned heat exchanger

Abstract

This utility model discloses a high-efficiency corrosion-resistant fin and heat exchanger, relating to the field of heat exchanger technology. The fin and heat exchanger exhibit a 20-30% increase in heat transfer coefficient, a 10-15% reduction in pressure drop, a 70% decrease in corrosion rate, a 3-5 times extension in service life, a 50% extension in maintenance cycle, and an overall energy efficiency ratio improvement of over 18%. The fin includes an asymmetrical sinusoidal wave shape, with the windward side tilt angle α being smaller than the leeward side tilt angle β. Turbulence holes are formed in the crest region of the fin, arranged in rows along the corrugation direction. Guide grooves are formed in the trough region of the fin. Turbulence protrusions are provided on the windward side of the fin, and turbulence slots are provided on the leeward side of the fin.

Description

Technical Field

[0001] This utility model relates to the field of heat exchanger technology, specifically to a high-efficiency corrosion-resistant fin and heat exchanger. Background Technology

[0002] Heat exchanger fins, as core components for enhancing heat transfer, are widely used in air conditioning, chemical, shipbuilding, and energy industries. However, traditional fins face severe challenges in corrosive media (such as those containing chloride ions and acidic gases) and high-humidity environments, mainly manifested in the following ways:

[0003] The contradiction between heat transfer and flow resistance is prominent: Although conventional symmetrical corrugated fins (such as straight and sawtooth types) can disturb the fluid, the symmetrical tilt design leads to insufficient flow field separation, thickening of the boundary layer, and increased thermal resistance. That is, the symmetrical structure is difficult to balance fluid resistance and eddy current intensity, and the boundary layer retention results in a low heat transfer coefficient. Experiments show that when the Reynolds number Re=2000, the heat transfer coefficient of symmetrical fins is less than 80 W / (m²·K), and the pressure drop loss is as high as 15% or more.

[0004] High risk of corrosion failure: Dead zones of liquid accumulation are easily formed in the trough area. Condensate or corrosive media tend to accumulate in the trough, inducing pitting corrosion, crevice corrosion and under-deposit corrosion, especially in media containing Cl⁻ (such as seawater cooling and chemical exhaust gas), the pitting rate is >0.5 mm / year.

[0005] Insufficient drainage and anti-clogging capabilities: Traditional flow guiding structures (such as flat-bottomed troughs and circular drainage holes) rely on gravity for drainage, but capillary force and surface tension are not utilized in synergy, resulting in a droplet residence time of >60 s, which aggravates electrochemical corrosion and reduces the effective heat exchange area;

[0006] Structural reliability defects: Microcracks are prone to occur at the edges of stamped fins (stress concentration factor Kt > 3.5), which become sources of corrosion fatigue under vibration conditions; Existing turbulence structures (such as stamped protrusions) generate local high stress due to abrupt shape changes, leading to plastic deformation of the substrate and a lifespan of less than 5 years.

[0007] Therefore, there is an urgent need to develop a finned structure that integrates high-efficiency heat transfer, active corrosion protection, and long-term reliability to overcome existing technological bottlenecks. Based on this, the applicant proposes a high-efficiency corrosion-resistant finned heat exchanger. Utility Model Content

[0008] The technical problem to be solved by this utility model is to overcome the defects of the existing technology and provide a high-efficiency corrosion-resistant fin and heat exchanger, which improves the heat transfer coefficient of the fin and heat exchanger by 20-30%, reduces the pressure drop by 10-15%, reduces the corrosion rate by 70%, extends the service life by 3-5 times, extends the maintenance cycle by 50%, and improves the overall energy efficiency ratio by more than 18%.

[0009] To solve the above-mentioned technical problems, the technical solution of this utility model is: a high-efficiency corrosion-resistant fin, comprising a fin, wherein the fin is in an asymmetrical sinusoidal wave shape, the angle α of the windward side of the fin is smaller than the angle β of the leeward side of the fin, the crest region of the fin is provided with turbulence holes, the turbulence holes are arranged in rows along the corrugation direction, the trough region of the fin is provided with guide grooves, the windward side of the fin is provided with turbulence protrusions, and the leeward side of the fin is provided with turbulence slots.

[0010] Furthermore, the windward tilt angle α of the fin is 18°-25°, and the leeward tilt angle β of the fin is 35°-45°.

[0011] Furthermore, the turbulence hole has an elliptical structure with a major axis length of 0.3 mm and an angle of 30° between the major axis of the turbulence hole and the corrugated ridge line.

[0012] Furthermore, the guide groove is arranged along the vertical direction of the corrugations, the guide groove has a V-shaped structure, and the guide groove extends through the entire length of the fin.

[0013] Furthermore, the fins are stamped using super austenitic stainless steel as the base material, the surface of the base material is nickel-plated, and a hydrophobic coating is applied to the surface of the fins.

[0014] Furthermore, the edges of the fins are provided with flanges.

[0015] Furthermore, the turbulence protrusion has a semi-ellipsoidal structure, the height of the turbulence protrusion is 1mm, the distance between two adjacent turbulence protrusions is 5mm, and the major axis of the turbulence protrusion forms a 30° angle of attack with the corrugation direction.

[0016] Furthermore, the turbulence slit is an inclined micro-slit with a width of 0.2 mm and a length of 2 mm. The direction of the turbulence slit is at a 60° angle to the direction of the corrugation. Each corrugation unit has 8 turbulence slits arranged alternately.

[0017] This solution also provides a high-efficiency corrosion-resistant heat exchanger, comprising the high-efficiency corrosion-resistant fins described in any one of the above embodiments, including heat exchange tubes and support plates. Two support plates are provided, and multiple fins are arranged between the two support plates. The heat exchange tubes pass through the fins and are fixed to the fins by expansion tubes. A top plate and a bottom plate are also fixed between the two support plates. The top plate and the bottom plate are located on the upper and lower sides of the fins, respectively, and multiple drainage holes are provided on both the bottom plate and the top plate. The bottom plate is inclined relative to the top plate, and the angle γ between the bottom plate and the horizontal direction is 3°.

[0018] Furthermore, the heat exchange tube is a U-shaped tube, and the other end of the heat exchange tube is connected by a connecting bend.

[0019] By adopting the above technical solution, this utility model has the following beneficial effects:

[0020] 1. The fins are in an asymmetrical sinusoidal wave shape with a small tilt angle on the windward side, which reduces fluid resistance and pressure drop by 7–12%, while the large tilt angle on the leeward side promotes the generation of strong vortices, enhances turbulent mixing, and increases the heat transfer coefficient by 15–25%.

[0021] 2. Elliptical turbulence holes disturb the boundary layer and generate directional microjets, breaking the thermal boundary layer; turbulence protrusions are set on the windward side to generate longitudinal vortices, guiding the core high-temperature fluid to the wall surface, improving the wall heat transfer efficiency by 18%.

[0022] 3. A turbulence slit is set on the leeward side to induce transverse micro-jet flow, enhance the transverse mixing of fluid, and reduce the temperature gradient; the V-shaped guide groove runs through the trough, and uses gravity and capillary action to collect condensate and direct it to both ends of the fins, eliminating more than 90% of local liquid accumulation and eradicating the root cause of pitting corrosion and under-deposit corrosion.

[0023] 4. The hydrophobic coating reduces droplet adhesion, promotes rolling and removal, and shortens the liquid film coverage time by 50%;

[0024] 5. The fins use super austenitic stainless steel as the base material, which is resistant to chloride stress corrosion. At the same time, the surface is nickel-plated to block electrochemical corrosion of the base material, and the thermal conductivity is maintained at >15 W / (m·K). The smooth flanged edges of the fins improve rigidity and reduce the installation damage rate by 40%.

[0025] 6. The 3° inclination design of the heat exchanger base plate ensures that condensate can be quickly discharged from the drain hole. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the high-efficiency corrosion-resistant fin of this utility model;

[0027] Figure 2 This is a front view of the high-efficiency corrosion-resistant fin of this utility model;

[0028] Figure 3 for Figure 2 Enlarged view of part A in the image;

[0029] Figure 4 This is a schematic diagram showing the tilt angles of the windward and leeward sides of the high-efficiency corrosion-resistant fins of this utility model.

[0030] Figure 5 This is a schematic diagram of the structure of the high-efficiency corrosion-resistant heat exchanger of this utility model;

[0031] Figure 6 This is a front view of the high-efficiency corrosion-resistant heat exchanger of this utility model.

[0032] Reference numerals: 1. Fin; 2. Support plate; 3. Heat exchange tube; 4. Top plate; 5. Bottom plate; 6. Connecting bend;

[0033] 7. Drainage hole; 11. Windward side; 12. Leeward side; 13. Turbation hole; 14. Guide channel; 15. Turbation protrusion;

[0034] 16. Turbulence slit; 17. Flanged edge; 18. Heat exchange hole. Detailed Implementation

[0035] To make the contents of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0036] In this embodiment, a high-efficiency corrosion-resistant fin is provided, including a fin 1. The fin 1 has an asymmetrical sinusoidal wave shape. The angle α of the windward side 11 of the fin 1 is smaller than the angle β of the leeward side 12 of the fin 1. A turbulence hole 13 is provided in the crest region of the fin 1. The turbulence hole 13 is arranged in a row along the corrugation direction. A flow guide groove 14 is provided in the trough region of the fin 1. A turbulence structure is also provided on the fin 1.

[0037] In this embodiment, the inclination angle α of the windward side 11 of fin 1 is 18°-25°, and the inclination angle β of the leeward side 12 of fin 1 is 35°-45°. The smaller inclination angle α of the windward side 11 of fin 1 makes the windward side 11 of fin 1 relatively gentle, which can reduce fluid resistance. The relatively larger inclination angle β of the leeward side 12 of fin 1 makes the leeward side 12 of fin 1 relatively steep, which can promote the generation of strong vortices, enhance turbulent mixing, and improve the heat transfer coefficient.

[0038] In this embodiment, the turbulence hole 13 has an elliptical structure with a major axis length of 0.3 mm. The angle between the major axis of the turbulence hole 13 and the corrugated ridge line is 30°. The design of the turbulence hole 13 can disturb the boundary layer, generate jets and wakes, enhance fluid mixing and turbulence. The edge of the elliptical hole is smoother and the stress concentration is smaller. The angle between the major axis of the turbulence hole 13 and the corrugated ridge line is 30°, which can utilize the small jets generated when the fluid flows through the hole, in conjunction with the asymmetric corrugations, to guide the fluid to flow along the desired path. The length of the major axis of the turbulence hole 13 is 0.3 mm, and the small holes are not easily blocked by large particles, which helps gas penetration and reduces local dead zones.

[0039] In this embodiment, the guide channel 14 is arranged along the vertical direction of the corrugations. The guide channel 14 has a V-shaped structure and runs through the entire length of the fin 1. By setting the guide channel 14, gravity, capillary action and surface tension can be used to collect and guide the condensate or corrosive droplets formed on the corrugated surface into the guide channel 14 and quickly discharge them along the guide channel 14 to both ends of the fin 1. This can prevent local liquid accumulation from causing pitting corrosion, crevice corrosion and under-deposit corrosion.

[0040] In this embodiment, fin 1 is stamped using super austenitic stainless steel as the base material. Super austenitic stainless steel has extremely high resistance to chloride pitting corrosion, crevice corrosion and stress corrosion cracking. The surface of the base material is nickel-plated, which can improve the corrosion resistance while ensuring the thermal conductivity of fin 1. At the same time, a hydrophobic coating is applied to the surface of fin 1, which greatly reduces the adhesion of liquid, especially water-based solutions, to the surface of fin 1, promotes droplet coalescence, rolling and sliding, significantly accelerates the drainage speed, and reduces the liquid film coverage time, thereby reducing the electrochemical corrosion rate and slowing down the concentration of corrosive media.

[0041] In this embodiment, the edge of the fin 1 is designed with a smooth flange 17, which can increase the rigidity of the fin 1 and reduce installation damage.

[0042] In this embodiment, the turbulence structure includes turbulence protrusions 15 disposed on the windward side 11 of the fin 1 and turbulence slots 16 disposed on the leeward side 12 of the fin 1.

[0043] Specifically, the turbulence protrusion 15 is a semi-ellipsoidal structure with a height of 1 mm and a spacing of 5 mm between two adjacent turbulence protrusions 15. The long axis of the turbulence protrusion 15 forms a 30° angle of attack with the corrugation direction. By setting the turbulence protrusion 15, longitudinal vortices can be generated, sweeping the high-temperature core fluid toward the wall surface, which can increase the contact area between the high-temperature fluid and the wall surface, thereby improving the heat transfer efficiency. At the same time, the low-temperature wall surface fluid is drawn into the core area, which can promote the mixing between fluids, further enhance the heat transfer effect, and also enhance the near-wall turbulent kinetic energy, destroy the thermal boundary layer, and increase the efficiency of heat transfer.

[0044] In this embodiment, the turbulence slit 16 is an inclined microslit with a width of 0.2 mm and a length of 2 mm. The direction of the turbulence slit 16 is at a 60° angle to the direction of the corrugation. Each corrugation unit is provided with 168 turbulence slits. By setting the turbulence slit 16, high-speed fluid passes through the microslit to form a microjet, thereby inducing a local high turbulence zone and enhancing lateral mixing.

[0045] In this embodiment, heat exchange holes 18 are provided on the fin 1.

[0046] This solution also provides a heat exchanger, which includes the aforementioned high-efficiency corrosion-resistant fins, as well as heat exchange tubes 3 and support plates 2. There are two support plates 2, and multiple fins 1 are arranged between the two support plates 2. The support plates 2 have through holes corresponding to the heat exchange holes 18 on the fins 1 through which the heat exchange tubes 3 pass. The heat exchange tubes 3 pass through the heat exchange holes 18 and are fixed to the fins 1 by expansion tubes. The heat exchange tubes 3 are U-shaped tubes, and the other end of the heat exchange tubes 3 is connected by connecting bends 6.

[0047] In this embodiment, a top plate 4 and a bottom plate 5 are fixedly provided between the two support plates 2. The top plate 4 and the bottom plate 5 are located on the upper and lower sides of the fin 1, respectively. Both the bottom plate 5 and the top plate 4 are provided with multiple drainage holes 7. At the same time, the bottom plate 5 is inclined relative to the top plate 4, and the angle γ between the bottom plate 5 and the horizontal direction is 3° to ensure that the condensate can flow out smoothly.

[0048] The present solution provides a high-efficiency corrosion-resistant fin and a heat exchanger including the fin 1. The fin 1 is an asymmetrical sinusoidal wave shape, with a small inclination angle on the windward side 11 to reduce fluid resistance and pressure drop by 7-12%, and a large inclination angle on the leeward side 12 to promote the generation of strong vortices, enhance turbulent mixing, and increase the heat transfer coefficient by 15-25%. Elliptical turbulence holes 13 disturb the boundary layer and generate directional microjets, breaking the thermal boundary layer. Turbulence protrusions 15 are provided on the windward side 11 to generate longitudinal vortices, guiding the core high-temperature fluid to the wall surface, improving the wall surface heat transfer efficiency by 18%. The wind face 12 is equipped with a turbulence slit 16 to induce transverse micro-jet flow, enhance transverse fluid mixing, and reduce temperature gradient; the V-shaped guide groove 14 runs through the trough, using gravity and capillary action to collect condensate and direct it to both ends of the fin 1, eliminating more than 90% of local liquid accumulation and eradicating the root causes of pitting and under-deposit corrosion; the hydrophobic coating reduces droplet adhesion, promotes rolling and removal, and shortens the liquid film coverage time by 50%; the fin 1 uses super austenitic stainless steel as the base material, which is resistant to chloride stress corrosion, and at the same time, the surface is nickel-plated to block electrochemical corrosion of the base material, and the thermal conductivity is maintained at >15. W / (m·K); the smooth edge of fin 1 with flange 17 improves rigidity and reduces installation damage rate by 40%; the 53° tilt design of the base plate ensures that condensate is quickly discharged from the drain hole 7; in summary, in this solution, the heat transfer coefficient of fin 1 and heat exchanger is increased by 20-30%, the pressure drop is reduced by 10-15%, the corrosion rate is reduced by 70%, the service life is extended by 3-5 times, the maintenance cycle is extended by 50%, and the overall energy efficiency ratio is improved by more than 18%.

[0049] The specific embodiments described above further illustrate the technical problems, technical solutions, and beneficial effects of this utility model. It should be understood that the above descriptions are merely specific embodiments of this utility model and are not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A high-efficiency corrosion-resistant fin comprising a fin (1), characterized in that: The fin (1) is in an asymmetrical sinusoidal wave shape. The angle α of the windward side (11) of the fin (1) is smaller than the angle β of the leeward side (12) of the fin (1). The crest region of the fin (1) is provided with turbulence holes (13), which are arranged in rows along the corrugation direction. The trough region of the fin (1) is provided with flow guide grooves (14). The windward side (11) of the fin (1) is provided with turbulence protrusions (15), and the leeward side (12) of the fin (1) is provided with turbulence slots (16).

2. The high-efficiency corrosion-resistant fin according to claim 1, characterized in that: The windward side (11) of the fin (1) has an inclination angle α of 18°-25°, and the leeward side (12) of the fin (1) has an inclination angle β of 35°-45°.

3. The high-efficiency corrosion-resistant fin according to claim 1, characterized in that: The turbulence hole (13) is an elliptical structure with a major axis length of 0.3 mm and an angle of 30° between the major axis of the turbulence hole (13) and the corrugated ridge line.

4. The high-efficiency corrosion-resistant fin according to claim 1, characterized in that: The guide groove (14) is arranged in the vertical direction of the corrugation. The guide groove (14) has a V-shaped structure and extends through the entire length of the fin (1).

5. The high-efficiency corrosion-resistant fin according to claim 1, characterized in that: The fin (1) is made of super austenitic stainless steel as the base material and is stamped. The surface of the base material is nickel plated and a hydrophobic coating is applied to the surface of the fin (1).

6. The high-efficiency corrosion-resistant fin according to claim 1, characterized in that: The edge of the fin (1) is provided with a flange (17).

7. The high-efficiency corrosion-resistant fin according to claim 1, characterized in that: The turbulence protrusion (15) is a semi-ellipsoidal structure with a height of 1 mm and a spacing of 5 mm between two adjacent turbulence protrusions (15). The major axis of the turbulence protrusion (15) forms a 30° angle of attack with the corrugation direction.

8. The high-efficiency corrosion-resistant fin according to claim 1, characterized in that: The turbulence slit (16) is an inclined micro-slit with a width of 0.2 mm and a length of 2 mm. The direction of the turbulence slit (16) is at a 60° angle to the direction of the corrugation. Each corrugation unit has 8 turbulence slits (16) interspersed.

9. A high-efficiency corrosion-resistant heat exchanger, comprising the high-efficiency corrosion-resistant fins as described in any one of claims 1-8, characterized in that: The device includes a heat exchange tube (3) and a support plate (2). There are two support plates (2), and multiple fins (1) are arranged between the two support plates (2). The heat exchange tube (3) passes through the fins (1) and is fixed to the fins (1) by an expansion tube. A top plate (4) and a bottom plate (5) are also fixed between the two support plates (2). The top plate (4) and the bottom plate (5) are located on the upper and lower sides of the fins (1), respectively. Multiple drainage holes (7) are opened on both the bottom plate (5) and the top plate (4). The bottom plate (5) is inclined relative to the top plate (4), and the angle γ between the bottom plate (5) and the horizontal direction is 3°.

10. The high efficiency corrosion resistant heat exchanger of claim 9, wherein: The heat exchange tube (3) is a U-shaped tube, and the other end of the heat exchange tube (3) is connected by a connecting bend (6).

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