Heat exchange fin structure, heat exchange tube and heat exchanger

Abstract

The application provides a heat exchange fin structure, a heat exchange pipe and a heat exchanger, relates to the technical field of heat exchange devices, and solves the technical problem of low condensation heat transfer efficiency of the existing heat exchange fin. The heat exchange fin structure comprises a main fin and a multiple-step secondary fin structure formed on the side surface of the main fin. The multiple-step secondary fin structure can increase the surface tension of the condensate film while piercing the condensate film, and accelerate the flow of the condensate to the fin root direction of the heat exchange fin. The application thins the thickness of the condensate film through the design of the multiple-step secondary fin structure on the side surface of the main fin. The multiple-step design realizes multiple adjustment and change of the curvature radius, increases the surface tension of the condensate film, promotes the rapid removal of the condensate film, and improves the condensation heat transfer efficiency of the heat exchange pipe and the heat exchanger by arranging the heat exchange fin structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat exchange devices, in particular to a heat exchange fin structure, a heat exchange tube and a heat exchanger. BACKGROUND

[0002] In the air conditioning and refrigeration industry, horizontal condensers have been rapidly developed due to their compact structure and wide applicability. High efficiency, energy saving and replacement of new refrigerants are still the main research directions. With the development of refrigeration technology and the needs of the times, the demand for high efficiency and energy saving in the field of refrigeration and air conditioning is becoming higher and higher, which also puts higher and higher requirements on the heat exchange performance of high-efficiency condensing heat exchange tubes used in condensers. Because the heat exchange tube is an important heat exchange and pressure-bearing unit, the improvement of the efficiency of the heat exchanger depends more on the performance of the heat exchange tube used. Therefore, developing more efficient and economical heat exchange tubes has become one of the focuses of research by major air conditioning manufacturers.

[0003] There are mainly three methods to improve the condensing heat exchange quantity Q: one is to increase the heat transfer area A, but the increase of the area will increase the cost; the second is to increase the heat transfer temperature difference, which is related to the working condition of heat exchange; the third is to improve the condensing heat transfer coefficient k. It has been proved in practice that improving the heat transfer coefficient k is the best way to save materials and energy. At present, double-sided reinforced high-efficiency heat exchange tubes are used in the shell-and-tube condensers of commercial air conditioning units to improve the heat transfer coefficient k. The improvement of k value mainly starts from improving the inner heat transfer coefficient hi and the outer heat transfer coefficient ho.

[0004] In the condenser heat exchange process, the phase change of the refrigerant on the outside of the condensing tube occurs for heat exchange, and the condensing liquid film formed on the surface of the heat exchange tube covers the condensing liquid film. The heat transfer resistance hinders the direct contact of the condensing liquid film with the vapor and the tube wall. The thicker the liquid film, the greater the heat resistance, and the worse the condensing heat transfer effect. The heat resistance distribution mainly exists outside the heat exchange tube. According to the weak side reinforcement principle, it is particularly important to strengthen the outside of the tube to maximize the reduction of the heat resistance outside the tube and improve the heat exchange performance.

[0005] The applicant finds that the prior art at least has the following technical problems:

[0006] The liquid film formed by the condensing liquid on the outside of the heat exchange tube is still the main heat resistance affecting the condensing heat transfer, especially the thickness of the liquid film in the condenser tube bundle. Although the prior art has tried to thin the liquid film through the design of the heat exchange fin, the effect is still not significant in actual application, and the condensing heat transfer efficiency is low. SUMMARY

[0007] The present application aims to provide a heat exchange fin structure, a heat exchange tube and a heat exchanger, which at least solve the technical problem of low condensing heat transfer efficiency of the heat exchange fin in the prior art. The preferred technical solutions in the many technical solutions provided by the present application can produce many technical effects, which are described in detail below.

[0008] To achieve the above object, the present application provides the following technical solutions.

[0009] The heat exchange fin structure provided by the present application comprises a main fin and a plurality of stepped sub-fin structures formed on the side surface of the main fin.

[0010] Optionally, the side surface of the main fin extends outward to form at least two layers of sub-fins distributed along the height direction of the main fin, thereby forming a plurality of stepped sub-fin structures.

[0011] Optionally, the overhang of the sub-fin in the lower layer is greater than that of the sub-fin in the upper layer along the height direction of the main fin.

[0012] Optionally, all the sub-fins are curved toward the fin root of the heat exchange fin.

[0013] Optionally, each layer of the sub-fins comprises at least two fins.

[0014] Optionally, a groove is formed between each pair of adjacent sub-fins.

[0015] Optionally, the cross-sectional shape of the groove is an inverted trapezoid, an inverted triangle or a rectangle.

[0016] Optionally, the main fin comprises a fin top and a fin root, and the fin top has an intermittent sawtooth-shaped tip.

[0017] Optionally, the sub-fins are formed on one side of the main fin or on both sides of the main fin.

[0018] The heat exchange pipe provided by the present application comprises a pipe base body and the heat exchange fin structure described above.

[0019] Optionally, the heat exchange fin structure is spirally arranged on the outer side of the pipe base body.

[0020] Optionally, the inner side of the pipe base body is provided with an inner rib.

[0021] Optionally, the heat exchange pipe is a condensing pipe.

[0022] The heat exchanger provided by the present application comprises the heat exchange pipe described above.

[0023] This invention provides a heat exchange fin structure and a heat exchange tube and heat exchanger having the same. The heat exchange fin structure includes a main fin and multiple stepped secondary fin structures formed on the side of the main fin. The multiple stepped secondary fin structures reduce the thickness of the condensate film in multiple ways. The multiple stepped arrangement realizes multiple adjustments and changes in the radius of curvature, increases the surface tension of the condensate film, and promotes the rapid drainage of the condensate film. The heat exchange fin structure improves the condensation heat transfer efficiency of the heat exchange tube and heat exchanger. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a three-dimensional structural schematic diagram of the first type of condenser heat exchanger provided in a specific embodiment of the present invention. The diagram is an unfolded view after being cut along the axial direction of the heat exchanger.

[0026] Figure 2 yes Figure 1 A circumferential view;

[0027] Figure 3 yes Figure 1 Axial view;

[0028] Figure 4 yes Figure 1 Top view of the heat exchanger tube structure;

[0029] Figure 5 This is a three-dimensional structural schematic diagram of the second type of condenser heat exchanger provided in a specific embodiment of the present invention. The diagram is an unfolded view after being cut along the axial direction of the heat exchanger tube.

[0030] Figure 6 yes Figure 5 Circumferential view;

[0031] Figure 7 yes Figure 5 Axial view;

[0032] Figure 8 yes Figure 5 Top view of the heat exchanger tube structure;

[0033] Figure 9 This is a schematic diagram of the main fins spirally distributed on the tube base.

[0034] In the diagram: 1. Tube base; 2. Inner rib; 3. Main wing; 4. Channel; 5. First layer of secondary wings; 6. Second layer of secondary wings; 7. Third layer of secondary wings; 8. Stepped shape; 9. Wing tip; 10. Groove. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0036] like Figures 1-9 As shown, the present invention provides a heat exchange fin structure, including a main fin 3 and a multi-step stepped secondary fin structure formed on the side of the main fin 3. The multi-step stepped secondary fin structure can increase the surface tension of the condensate film while piercing the condensate film, and accelerate the flow of condensate towards the root of the heat exchange fin.

[0037] The multi-step secondary fin structure relies on gravity to reduce the thickness of the condensate film in multiple stages. As the secondary fin structure pierces the liquid film, the multiple steps allow for multiple adjustments and changes in the radius of curvature, increasing the surface tension of the condensate film. Moreover, each step provides a pulling force towards the fin root under the action of pressure difference. The superposition of multiple pulling forces promotes the rapid discharge of the condensate film, preventing the condensate from stagnating and bridging between the main fins 3. This ensures that the refrigerant and heat exchange tubes have sufficient contact and heat exchange, thereby improving the condensation heat transfer efficiency of the heat exchange tubes and heat exchanger after the installation of this heat exchange fin structure.

[0038] As an optional implementation, the side of the main wing 3 extends and protrudes away from the main wing 3 to form at least two layers of secondary wings distributed along the height direction of the main wing 3, so as to form a multi-step secondary wing structure.

[0039] At least two layers of secondary fins extend from the side of the main fin 3 away from it, forming protrusions distributed along the height of the main fin 3. These secondary fins can pierce the liquid film, increasing the contact between the refrigerant and the heat exchange tube wall. Furthermore, the arrangement of at least two stepped layers 8 allows for multiple liquid film separation and thinning under gravity due to the height difference. Additionally, the difference in the radius of curvature of the secondary fins increases the pressure difference between the top and root of the main fin 3, and each layer of secondary fins generates a downward pulling force. Their combined effect further promotes the rapid flow of the condensate film towards the root. Moreover, this heat exchange fin structure also increases the heat exchange surface area and improves heat exchange performance.

[0040] In two embodiments of the present invention, the multi-step stepped secondary wing structure includes a first layer of secondary wings 5, a second layer of secondary wings 6, and a third layer of secondary wings 7.

[0041] As an optional embodiment, as shown in Figure 2 and Figure 6 the length of the auxiliary fins in the lower layer is greater than that of the auxiliary fins in the upper layer along the height direction of the main fins 3. The above structure causes the radius of curvature Rc of the heat exchange fins to change, and the driving force (the pressure difference of the condensed liquid) for the condensed liquid film to flow to the fin root increases. When the condensed liquid flows from the fin top 9 to the fin root, it is stretched and thinned by the auxiliary fins, and the flow is accelerated. Thus, the flow of the condensed liquid can be further promoted.

[0042] As an optional embodiment, all the auxiliary fins are curved towards the fin root of the heat exchange fins. The curved structure causes the radius of curvature of the cross section of the auxiliary fins to also differ, and promotes the flow of the liquid film to the fin root; and the downward curved direction can avoid "catching" the liquid, so that the fluid constituting the liquid film is quickly discharged, and the heat exchange fins are as exposed as possible to improve the heat exchange performance.

[0043] As an optional embodiment, each layer of auxiliary fins includes at least two fins. The provision of at least two fins increases the heat exchange area and can further stretch and thin the liquid film.

[0044] As an optional embodiment, a groove 10 is formed between each adjacent two auxiliary fins, and the groove 10 is a sunken groove.

[0045] On the one hand, the provision of the groove 10 can further increase the heat exchange area; on the other hand, since the flow direction of the refrigerant outside the horizontal heat exchange tube is along the vertical cross section of the heat exchange tube, for any main fin 3 in the flow direction, the flow is approximately along the height direction of the main fin 3, and the groove 10 can disturb the refrigerant flowing therethrough to improve the heat exchange efficiency.

[0046] As an optional embodiment, the cross-sectional shape of the groove 10 is an inverted trapezoid, an inverted triangle or a rectangle. The use of the above cross-sectional shape facilitates the action on the refrigerant, forms fluctuations by blocking the refrigerant, and further improves the heat exchange effect.

[0047] As an optional embodiment, the main fin 3 includes a fin top 9 and a fin root, and the fin top 9 has an intermittent sawtooth-shaped tip. The sawtooth-shaped tip can first pierce and thin the liquid film, and the intermittent arrangement can form multiple tips close to "independent" for the fin top 9, effectively strengthening the thinning of the liquid film.

[0048] As an optional embodiment, the auxiliary fins are formed on one side of the main fin 3 or on opposite sides of the main fin 3. Figures 1-4 and Figures 5-8 Two embodiments are respectively given, in which the auxiliary fins are formed on both sides of the main fin 3 and the auxiliary fins are formed on one side of the main fin 3.

[0049] Example 1:

[0050] AsFigures 1-4 As shown, the heat exchange tube of the present application comprises a tube base body 1 and spiral main fins 3 integrally formed on the outer side of the tube base body 1, the integral spiral main fins 3 comprise fin top 9, base body, root and side wall, and the channel 4 is formed between the side walls of the adjacent two main fins 3. The top of the main fin 3 is formed into sharp serrated intermittent fin by extrusion, and the first layer of "crescent" auxiliary fin structure extending to both sides of the fin is formed at the bottom of the serrated intermittent fin at the top of the main fin 3, the auxiliary fin bends towards the groove of the main fin 3 and extends to both sides of the main fin 3 by h6. The serrated fin forms a certain angle α with the axial direction of the main fin 3; the main fin 3 is in a stepped shape 8, and the second layer of auxiliary fin 6 structure is formed at the step, the auxiliary fin bends towards the groove of the main fin 3 and extends to both sides of the main fin 3 by h5; the inverted trapezoidal groove 10 is formed on both sides of the main fin 3, and the shape of the groove 10 can also be rectangular, inverted triangular, etc., and the third layer of auxiliary fin 7 structure is formed at the bottom of the inverted trapezoidal groove 10. The extension of the first layer of auxiliary fin 5 and the second layer of auxiliary fin to the fin side wall is less than the extension h4 of the third layer of auxiliary fin 7 to the fin side wall; the inner rib 2 is arranged on the inner side of the tube.

[0051] The spiral main fin 3 is provided with 19-60 per inch along the axial direction of the heat exchange tube, the root of the main fin 3 is connected with the tube body integrally, and the height h0 of the main fin 3 is 0.1-2.0 mm.

[0052] The fin top 9 of the spiral main fin 3 has an intermittent serrated knurl structure, which forms an included angle α with the axial direction of the fin, the included angle α is 0-90°, the knurl depth h9 is 0.05-1.0 mm, and the thickness h8 of the main fin 3 is 0.05-0.6 mm;

[0053] The root of the knurl structure of the fin top 9 forms the first layer of auxiliary fin 5, which has a certain height h3 of 0.05-1.95 mm from the heat exchange tube base body 1, and the first layer of auxiliary fin 5 protrudes and extends to the fin side surface by h6 of 0.01-1.0 mm;

[0054] The side surface of the main fin 3 forms a stepped structure 8, the step thickness h7 is 0.01-0.55 mm, and the second layer of auxiliary fin 6 is formed at the step, the second layer of auxiliary fin 6 protrudes and extends to the fin side surface by h5 of 0.01-1.0 mm;

[0055] The side surface of the main fin 3 forms an inverted trapezoidal groove 10 structure, the inverted trapezoidal angle β is 0-160°, and the bottom width h10 of the inverted trapezoidal groove is 0.01-0.6 mm;

[0056] The bottom of the groove 10 on the side surface of the main fin 3 forms the third layer of auxiliary fin 7 towards the fin side surface, which has a certain height h1 of 0.05-1.95 mm from the heat exchange tube base body 1, and the third layer of auxiliary fin 7 protrudes and extends to the fin side surface by h4 of 0.01-1.0 mm;

[0057] The inner rib 2 in the tube body is in a thread shape, the cross section of the thread-shaped inner rib 2 is trapezoidal, and the tooth top angle of the inner rib 2 is 10-110°.

[0058] The angle between the inner thread rib 2 and the axis of the pipe body ranges from 1 to 75°, the number of inner ribs 2 is from 10 to 120, and the height of inner rib 2 is from 0.1 to 0.7 mm.

[0059] In this embodiment, the secondary wings are arranged on both sides of the main wing 3, which increases the heat exchange area and enhances heat exchange.

[0060] Example 2:

[0061] like Figures 5-8 As shown, the heat exchange tube includes a tube base 1 and a spiral main fin 3 integrally formed with the outer side of the tube base 1. The integral spiral main fin 3 includes a fin tip 9, a base, a root, and a sidewall. A channel 4 is formed between the sidewalls of the two main fins 3. The top of the main fin 3 is formed into sharp, serrated, discontinuous fins by extrusion. At the bottom of the discontinuous serrated fins at the top of the main fin 3, a first layer of secondary fins 5 is formed, extending towards one side of the fin, with a "crescent-shaped" structure. This secondary fin bends towards the groove of the main fin 3 and extends h6 towards one side of the main fin 3. The serrated fins are at a certain angle α to the axial direction of the main fin 3. The main fin 3 is stepped 8, and a second layer of secondary fins 6 is formed at the step. This secondary fin bends towards the groove of the main fin 3 and extends h5 towards one side of the main fin 3. An inverted trapezoidal groove 10 is formed on one side of the main fin 3 (the side with the secondary fins). The cross-section of the groove 10 can also be rectangular or inverted triangular, etc. A third layer of secondary fins 7 is formed at the bottom of the inverted trapezoidal groove 10. The extension of the first-layer secondary wing 5 and the second secondary wing to the wing sidewall is less than the extension of the third-layer secondary wing 7 to the wing sidewall h4; an inner rib 2 is provided on the inner side of the tube.

[0062] The spiral main wing 3 has 19 to 60 winglets per inch along the axial direction. The root of the main wing 3 is connected to the tube body as one piece. The height of the main wing 3 is h0 = 0.1 to 2.0 mm.

[0063] The intermittent serrated knurled structure of the tip 9 of the spiral main wing 3 forms an angle α with the wing axis, the angle α being 0 to 90°, the knurling depth h9 being 0.05 to 1.0 mm, and the thickness of the main wing 3 being h8 being 0.05 to 0.6 mm.

[0064] The first layer of secondary fins 5 is formed at the root of the knurled structure at the fin tip 9, and is at a certain height h3 = 0.05~1.95mm with the heat exchange tube base 11. The first layer of raised secondary fins extends to the side of the fin by h6 = 0.01~1.0mm.

[0065] The main wing 3 forms a stepped structure 8 on its side, with a step thickness h7 = 0.01~0.55mm. A second layer of secondary wings 6 is formed at the step, and the second layer of secondary wings 6 protrudes and extends towards the side of the wing by h5 = 0.01~1.0mm.

[0066] The main fin 3 side forms an inverted trapezoidal groove 10 structure, the inverted trapezoidal angle β=0~160°, the inverted trapezoidal bottom width h10=0.01~0.6mm;

[0067] The main fin 3 side groove 10 bottom to the fin side forms a third layer of auxiliary fin 7, and the heat exchange pipe base 1 is a certain height h1=0.05~1.95mm, and the third layer of auxiliary fin 7 extends to the fin side protrusion h4=0.01~1.0mm;

[0068] The inner rib 2 in the pipe body is screw thread, the cross section of the screw thread inner rib 2 is trapezoidal, and the tooth top angle of the inner rib 2 ranges from 10 to 110 degrees.

[0069] The angle between the screw thread inner rib 2 and the axis of the pipe body ranges from 1 to 75 degrees, the number of the inner rib 2 is 10~120, and the height of the inner rib 2 is 0.1~0.7mm.

[0070] In this embodiment, the auxiliary fin is located on one side of the main fin 3, which can reduce the fin spacing and prevent condensate from being retained during condensation process, thereby enhancing heat exchange.

[0071] The application also provides a heat exchange pipe, which comprises a pipe base 1 and a heat exchange fin structure according to any one of the above.

[0072] As an optional embodiment, as shown in Figure 9 The heat exchange fin structure is spirally arranged on the outer side of the pipe base 1 (the dotted line in the figure shows the spiral arrangement state of the main fin). The main fin 3 is spirally distributed by extrusion molding, so that it is formed by spirally advancing with the cutter extrusion.

[0073] As an optional embodiment, the inner side of the pipe base 1 is provided with an inner rib 2, which can increase the heat transfer area of the heat exchange pipe, and also can increase the turbulence of the fluid in the heat exchange pipe, thereby increasing the heat exchange efficiency of the heat exchange pipe.

[0074] As an optional embodiment, the heat exchange pipe is a condensing pipe.

[0075] The application also provides a heat exchanger comprising any one of the above heat exchange pipes.

[0076] The outer side of the heat exchange pipe of the present application is a spiral ladder-shaped fin structure, the top of the main fin 3 is rolled to form a notch, an independent sawtooth-shaped sharp top end structure is formed at the top 9 of the fin, and a first layer of auxiliary fin 5 is formed on both sides of the main fin 3, which is pressed to the two sides of the fin. The auxiliary fin is a "crescent moon" sharp protrusion curved towards the fin root. A second layer of auxiliary fin 6 structure is formed on the ladder-shaped steps of one side of the fin, and the second layer of auxiliary fin 6 is also a "crescent moon" sharp protrusion curved towards the fin root. This structure causes the difference in curvature radius between the top 9 of the fin and the fin root, increases the pressure difference between the top and the root of the condensate fin, and promotes the thinning of the liquid film and the flow of the condensate to the fin root. The auxiliary fin extending outward from the side wall of the main fin not only increases the heat transfer area outside the pipe, but also changes the curvature radius of the condensate film, fully utilizes the effect of surface tension, and speeds up the downward flow of the condensate film; moreover, the sharp end of the auxiliary fin can pierce the condensate film, enhance the contact between the heat exchange fin and the refrigerant vapor, further promote heat transfer, and improve the heat exchange effect of the heat exchanger.

[0077] The inverted trapezoidal groove 10 formed on the side wall of the fin can increase the heat exchange area and guide the flow, and the capillary siphon principle of the groove 10 can quickly guide the condensate at the top of the fin to the bottom of the fin root and quickly drain along the flow channel, further thinning the thickness of the condensate, reducing the bridging of the condensate between the fins, and allowing more fin area to participate in heat exchange, thereby improving the condensation heat transfer coefficient.

[0078] The third layer of auxiliary fin 7 structure is arranged at the bottom of the inverted trapezoidal groove 10 formed on the side wall of the main fin 3, which increases the heat transfer area, and when the condensate flows from the top 9 of the fin to the fin root, it will be stretched and thinned when passing through the auxiliary fin, speeding up the flow. The condensate can be enhanced, and the turning of the condensate flowing through it is further enhanced. From a mechanism point of view, the curvature radius of the fin top 9 and the sharp end of the auxiliary fin is the smallest, while the curvature radius of the auxiliary fin and the fin root 3 is larger. From the fin top 9 to the auxiliary fin, and from the auxiliary fin to the fin root, there will be two sections of condensate pressure difference, which utilizes the effect of surface tension to promote the flow of condensate, thereby improving the condensation heat transfer coefficient.

[0079] Through the arrangement of the multiple ladder-shaped 8 auxiliary fins, the condensate can be thinned on the fin side wall and quickly drained along the flow channel, ensuring that the liquid film at the sharp top 9 of the fin is thinnest and avoiding local accumulation of the condensate, thereby enhancing heat exchange; further reducing the adverse effects of the condensate film on condensation heat transfer, and further improving the heat exchange efficiency of the condensation pipe.

[0080] The inner rib 2 structure in the heat transfer pipe also has a screw shape, which increases the heat transfer area of the heat transfer pipe and enhances the turbulent flow of the fluid in the heat transfer pipe, thereby increasing the heat transfer efficiency of the pipe.

[0081] In the description of the application, it should be noted that, unless otherwise specified, the meaning of "a plurality of" is two or more; the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the purpose of facilitating the description of the application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application. In addition, the terms "first", "second", "third" and the like are only for the purpose of description and cannot be understood as indicating or implying relative importance.

[0082] In the description of the application, it should also be noted that, unless otherwise specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0083] The above is only a specific embodiment of the application, but the protection scope of the application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the application, which should be covered within the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A heat exchange fin structure, characterized by, The main fin and the multiple stepped sub-fin structures formed on the side of the main fin can break the condensate film and increase the surface tension of the condensate film, thus accelerating the flow of the condensate to the root of the heat exchange fin; The side of the main fin extends outward to form at least two layers of sub-fins along the height direction of the main fin, thus forming the multiple stepped sub-fin structures; The overhang of the sub-fin in the lower layer is greater than that of the sub-fin in the upper layer along the height direction of the main fin; all the sub-fins are curved toward the root of the heat exchange fin; The main fin includes a fin top and a fin root, and the fin top has intermittent serrated tips; the intermittent serrated tips can form independent multiple tips on the fin top.

2. The heat exchange fin structure according to claim 1, wherein Each layer of the sub-fin includes at least two fins.

3. The heat exchange fin structure according to claim 2, wherein A groove is formed between each two adjacent sub-fins.

4. The heat exchange fin structure according to claim 3, wherein The cross-sectional shape of the groove is inverted trapezoidal, inverted triangular or rectangular.

5. The heat exchange fin structure according to claim 1, wherein The sub-fins are formed on one side of the main fin or on both sides of the main fin.

6. A heat exchange tube, characterized by, The heat exchange fin structure as claimed in any one of claims 1-5 is formed on the outer side of the tube base.

7. The heat exchange tube according to claim 6, wherein The heat exchange fin structure is spirally arranged on the outer side of the tube base.

8. The heat exchange tube of claim 6, wherein The inner side of the tube base is provided with an inner rib.

9. The heat exchange tube of claim 6, wherein The heat exchange tube is a condenser tube.

10. A heat exchanger, characterized by The heat exchange tube as claimed in any one of claims 6-9. The heat exchange tube as claimed in any one of claims 6-9.

Images