A multi-stage internal fin high-efficiency heat exchange element

Abstract

The present invention provides a multi-stage internal fin high-efficiency heat exchange element, belonging to the technical field of heat exchange elements. The multi-stage internal fin high-efficiency heat exchange element includes an outer tube and a plurality of fin units. The fin units are evenly distributed circumferentially on the inner wall of the outer tube. The fin unit includes: a first fin, the root of the first fin is connected to the inner wall of the outer tube and extends from the outer tube wall towards the center of the outer tube; a second fin, distributed on both sides of the first fin, and two adjacent second fins form a rectangular opening. By setting the first fin and the second fin, the heat exchange area can be increased, thereby improving the heat exchange efficiency. By forming a rectangular opening between two adjacent second fins and making the rectangular opening and the flow channel form a wavy fluid channel, the fluid can swing more greatly, thereby increasing the thermal contact area between the fluid and the first fin and the second fin, and significantly improving the heat exchange efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat exchange elements, and particularly relates to a multi-stage internal fin high-efficiency heat exchange element. Background Art

[0002] In the field of heat exchange, the heat exchange efficiency of traditional smooth tubes is difficult to meet the growing industrial demands. The heat transfer between the fluid on the inner and outer walls of the smooth tube and the tube wall mainly relies on convective heat transfer, and the heat transfer coefficient is relatively low. To improve the heat transfer efficiency, internal fin tubes emerged. By machining fin structures on the inner surface of the tube, the internal fin tubes greatly increase the heat exchange area. Compared with smooth tubes, the internal fin tubes can make the fluid inside the tube form a stronger disturbance, thinning the boundary layer, thereby significantly increasing the heat transfer coefficient of the fluid inside the tube and enhancing the overall heat exchange performance. This structural improvement has been widely applied in heat exchangers in many industries such as chemical engineering, energy, and refrigeration, effectively improving the energy utilization efficiency and reducing the equipment volume and cost.

[0003] In the Chinese patent with the publication number CN105444602A, a new type of internal fin tube for boilers is disclosed. The internal fin tube includes a cylindrical hollow outer tube, and an aluminum insert is embedded in the outer tube. The insert consists of two semi-cylindrical shell comb-like structures. Small fins are also provided on the surface of the comb teeth. The small fins on the comb teeth are unequal-height fins in the radial direction of the outer tube. The comb teeth of the two semi-cylindrical shell comb-like structures are arranged staggeredly, and the two ends of the two semi-cylindrical shell comb-like structures are connected to each other. From the inlet to the outlet direction, the comb teeth gradually become longer or remain unchanged after gradually becoming longer to a certain length in the radial direction of the outer tube.

[0004] However, for the internal fin tube in the above technical solution, the contact area between the fins inside the tube and the flowing medium is small, and the heat exchange area is small, which in turn leads to a relatively low thermal conductivity coefficient and a low heat exchange efficiency, unable to meet the heat exchange requirements of high-temperature fluids. Summary of the Invention

[0005] The purpose of the present invention is to provide a multi-stage internal fin high-efficiency heat exchange element, aiming to solve the problem that the heat exchange efficiency of the new type of internal fin tube for boilers in the existing technology cannot meet the heat exchange requirements of high-temperature fluids and needs to further improve the heat exchange efficiency.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A multi-stage internal fin high-efficiency heat exchange element, comprising: an outer tube and a plurality of fin units. The fin units are evenly distributed in a circumferential direction on the inner wall of the outer tube. The fin unit includes:

[0007] A first fin, the root of the first fin is connected to the inner tube wall of the outer tube and extends from the outer tube wall towards the tube center of the outer tube;

[0008] A plurality of second fins are distributed on both sides of the first fin. Two adjacent second fins form a rectangular opening, and there is a spacing between the second fins on the opposite sides, constituting a flow channel communicating with the rectangular opening. The length of the second fin gradually increases from the tube center towards the tube wall. The second fins are arranged staggeredly along the direction from the outer tube center to the outer tube inner wall, so that the flow channel and the rectangular opening form a wavy fluid channel.

[0009] A further technical solution of the present invention is that the fin unit is arranged on the inner wall of the outer tube in a spiral shape.

[0010] A further technical solution of the present invention is that the outer tube includes a plurality of splicing tubes. The splicing tubes are combined into a complete outer tube through a clamping structure. The fin unit is arranged on the splicing tubes, and the splicing tubes extend along the extension direction of the fin unit.

[0011] A further technical solution of the present invention is that the clamping structure includes a clamping groove located on one side of the splicing tube and a clamping block located on the other side. The clamping grooves and clamping blocks on two adjacent splicing tubes cooperate with each other. Limiting grooves are also arranged on both sides of the clamping block, and limiting blocks adapted to the limiting grooves are arranged at the opening of the clamping groove.

[0012] A further technical solution of the present invention is that a sealing member is arranged between the clamping groove and the clamping block to improve the sealing effect at the joint.

[0013] A further technical solution of the present invention is that a flow disturbing member is arranged on the outer tube. The flow disturbing member includes a diffusion part and a converging part. A flow channel penetrating through the converging part and extending into the fluid channel is arranged on the diffusion part. High-temperature fluid can be guided along the outer surface of the diffusion part and the flow channel, and the high-temperature fluid is guided into the fluid channel. The diameter of one end of the converging part is close to the diameter of the outer tube and can cover the fluid channel. The other end is provided with a through hole, and low-temperature fluid converges towards the middle of the outer tube under the guidance of the converging part.

[0014] A further technical solution of the present invention is that a plurality of installation grooves are arranged on the flow disturbing member, and the fin unit is inserted into the installation grooves for installing the flow disturbing member.

[0015] A further technical solution of the present invention is that the fin root thickness of both the first fin and the second fin is greater than the fin tip thickness.

[0016] A further technical solution of the present invention is that fillets are arranged at the fin tips of the first fin and the second fin.

[0017] A further technical solution of the present invention is that the second fins on the adjacent side are parallel to each other.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. By setting the first fin and the second fin, the heat exchange area can be increased, thereby improving the heat exchange efficiency. By forming a rectangular opening between two adjacent second fins, and making the rectangular opening and the flow channel form a wavy fluid channel, the fluid can swing more significantly, thereby increasing the thermal contact area between the fluid and the first fin and the second fin, and significantly improving the heat exchange efficiency.

[0020] 2. By spirally arranging the fin unit on the inner wall of the outer tube, the fluid can contact more heat exchange surfaces during the flow process, and the fluid is prompted to flow in a spiral shape along the fluid channel. Compared with axial flow, this flow mode effectively prolongs the residence time of the fluid on the fin unit, thereby providing more time for heat exchange.

[0021] 3. By setting up seals, the sealing effect of the joints can be improved, effectively preventing fluid leakage.

[0022] 4. The flow of part of the high-temperature fluid and the low-temperature fluid can be effectively guided by the spoiler, realizing the displacement of the fluid position. At the same time, the spoiler can also perform flow disturbance treatment on the fluid, significantly improving the heat exchange efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 It is a structural schematic diagram of the first embodiment of the present invention;

[0025] Figure 2 It is a structural schematic diagram of the second embodiment of the present invention;

[0026] Figure 3 It is a schematic diagram of the installation structure of the spoiler in a specific embodiment of the present invention;

[0027] Figure 4 It is a structural schematic diagram of a spoiler in a specific embodiment of the present invention;

[0028] Figure 5 In the specific embodiment of the present invention Figure 2 A schematic diagram of the enlarged structure at point A in the middle.

[0029] In the figure: 1. Heat exchange tube body; 11. Outer tube; 111. Splicing tube; 12. Fin unit; 121. First fin; 122. Second fin; 123. Rectangular opening; 124. Fluid channel; 125. Flow channel; 2. Clamping structure; 21. Card slot; 211. Limit block; 22. Card block; 221. Limit groove; 23. Seal; 3. Flow disturbing member; 31. Diffusion part; 32. Converging part; 33. Flow channel; 34. Through hole; 35. Installation groove. Detailed implementation manners

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] Please refer to Figures 1 - 5 , the present invention provides the following technical solutions: A multi-stage internal fin high-efficiency heat exchange element includes a heat exchange tube body 1, and a smooth tube is sleeved on the outer surface of the heat exchange tube body 1.

[0032] Please refer to Figure 1 , in Embodiment 1, the heat exchange tube body 1 is composed of a cylindrical outer tube 11 and 16 fin units 12 arranged circumferentially and uniformly along the axis of the outer tube 11. The fin units 12 extend along the length direction of the outer tube 11. Both the fin units 12 and the outer tube 11 are made of silicon-aluminum alloy material and are manufactured by an integral molding process. The fin units 12 are arranged on the inner tube wall of the outer tube 11. The cross section of the fin units 12 extends from the inner wall of the outer tube 11 towards the tube center direction, which can increase the heat exchange area and thus significantly improve the heat exchange efficiency;

[0033] The fin unit 12 is composed of an integrally formed first fin 121 and a plurality of second fins 122. The root of the tooth of the first fin 121 is connected to the inner tube wall of the outer tube 11, and the tooth tip extends towards the tube center direction of the outer tube 11. On each first fin 121, a plurality of second fins 122 are provided. These second fins 122 are evenly distributed on both sides of the first fin 121. The second fins 122 on the adjacent side are parallel to each other and jointly form a rectangular opening 123. Between two adjacent first fins 121, there is a certain distance between the second fins 122 on the opposite side, thus forming a flow channel 125 communicating with the rectangular opening 123;

[0034] It should be noted that since the center of the outer tube 11 is relatively far from the water flow, the temperature is relatively high. The inner wall of the outer tube 11 is in close contact with the water flow and has a lower temperature. To avoid the melting of the second fin 122 caused by high temperature, the length of the second fin 122 is adjusted during manufacturing. From the center of the tube to the tube wall, the length of the second fin 122 gradually increases. This not only ensures the effective heat dissipation area of the fin but also greatly reduces the risk of the fin melting due to high temperature. Especially in the central region of the outer tube 11, the length of the second fin 122 is designed to be relatively short to adapt to the higher temperature environment;

[0035] The second fins 122 on the opposite sides are arranged staggeredly along the direction from the center of the outer tube 11 to the inner wall of the outer tube 11. This design makes the rectangular openings 123 on the opposite sides also show a staggered distribution. Such a layout not only increases the distance between the fin tops of two adjacent second fins 122, effectively reducing the resistance encountered by the fluid during flow, but also combines the flow channel 125 with the rectangular opening 123 to form a wavy fluid channel 124. In such a fluid channel 124, the flowing fluid can swing more significantly, thereby increasing the thermal contact area between the fluid and the first fin 121 and the second fin 122 and significantly improving the heat exchange efficiency;

[0036] Round corners are provided at the fin tops of the first fin 121 and the second fin 122. This design aims to reduce the stress concentration phenomenon and thus improve the overall structural strength. In addition, the thickness of the fin root is designed to be greater than that of the fin top because the fin root, as the key connection part between the fin and the outer tube 11, needs to bear greater stress and pressure. Therefore, the thicker fin root can provide more stable mechanical support and enhance the structural strength, ensuring that the fin is not easily detached or damaged during long-term use. The fin tip part is far from the base tube and bears relatively small stress and pressure. Therefore, we can appropriately reduce the thickness of the fin tip part to improve the heat transfer performance, and such a design will not have a significant impact on the overall mechanical strength.

[0037] Please refer to Figure 2, in the second embodiment, different from the first embodiment, the fin units 12 are arranged in a spiral shape on the inner wall of the outer tube 11 and are evenly arranged circumferentially along the axis of the outer tube 11 to ensure that the spacing between adjacent fin units 12 remains consistent. This design of the spiral-distributed fin units greatly increases the heat exchange area. Compared with the fin units 12 arranged along the axis of the outer tube 11 in the first embodiment, the fluid can contact more heat exchange surfaces during the flow process. In addition, the spiral arrangement of the fin units 12 also makes the fluid channels 124 form a spiral distribution along the axis direction of the outer tube 11, prompting the fluid to flow spirally along the fluid channels 124. Compared with the axial flow, this flow mode effectively extends the residence time of the fluid on the fin units 12, thus providing more ample time for heat exchange.

[0038] Please continue to participate Figure 2 , in the third embodiment, the outer tube 11 is evenly divided into a plurality of spliced tubes 111 along the circumferential direction, and these spliced tubes 111 are connected to each other through the clamping structure 2, so as to be able to form a complete shape of the outer tube 11. One to four fin units 12 are installed on each spliced tube 111. To simplify the production process, the spliced tubes 111 extend along the extension direction of the fin units 12. Specifically, if the fin units 12 extend along the horizontal axis, the spliced tubes 111 can also extend along the horizontal axis parallel to the fin units 12. If the fin units 12 extend in a spiral manner, the spliced tubes 111 can extend along the spiral direction with the same pitch as the fin units 12. Such a design not only ensures the integrity of the fin units 12 after splicing, but also greatly improves the convenience of producing the spliced tubes 111 and the fin units 12.

[0039] Please continue to participate Figure 2 and Figure 5 , the clamping structure 2 is composed of a clamping groove 21 arranged on one side of the spliced tube 111 and a clamping block 22 arranged on the other side. The clamping grooves 21 and the clamping blocks 22 on two adjacent spliced tubes 111 are mutually matched. By clamping the clamping block 22 into the clamping groove 21, a plurality of spliced tubes 111 can be assembled. However, during the splicing process, when the number of spliced tubes 111 is large, if there is no firm fixation between adjacent spliced tubes 111, the clamping block 22 may slip out of the clamping groove 21. To solve this problem, limiting grooves 221 are designed on both sides of the clamping block 22, and limiting blocks 211 are arranged at the opening of the clamping groove 21. The mutual cooperation between the limiting grooves 221 and the limiting blocks 211 effectively limits the freedom degree of the clamping block 22 in the clamping groove 21, enabling the clamping block 22 to only slide along the inside of the clamping groove 21, thus avoiding the problem of difficult splicing caused by the accidental sliding out of the clamping block 22 from the clamping groove 21 during the assembly process;

[0040] Inside the card slot 21, a seal 23 is installed. Its main function is to ensure a good sealing effect at the joint of the splicing pipe 111, thus effectively preventing fluid leakage. The seal 23 used here is a vermiculite pad. This material has unique properties: in a high-temperature environment, the vermiculite pad can expand. This expansion property not only enhances the fit between the seal 23 and the splicing pipe 111 but also further improves the sealing effect, ensuring that even under high-temperature conditions, the fluid will not leak from the joint.

[0041] Please continue to participate Figure 3 and Figure 4 , since the temperature at the central part of the outer pipe 11 is relatively high while the temperature at its inner wall is relatively low, it is difficult for the central high temperature to be effectively transferred to the surface of the fin unit 12, thereby reducing the heat exchange efficiency. To solve this problem, a turbulator 3 is provided at the central position of the outer pipe 11;

[0042] The turbulator 3 is composed of a diffusion part 31 and a converging part 32. These two parts can be integrally formed by the sand casting process. On the diffusion part 31, a flow channel 33 passing through the converging part 32 is designed. The outlet of the flow channel 33 extends into the fluid channel 124. The diffusion part 31 is designed in a conical shell shape and is installed at the axial center position of the outer pipe 11, with its conical tip facing the direction of fluid flow. Such a layout enables the fluid to smoothly guide the high-temperature fluid into the fluid channel 124 along the outer surface of the diffusion part 31 and the guidance of the flow channel 33. Relatively, the converging part 32 is designed in a conical shell shape matching the diffusion part 31, with its conical tip facing the direction of fluid flow. The diameter of the end of the converging part 32 away from the conical tip is close to the diameter of the outer pipe 11. This design enables the converging part 32 to effectively cover the fluid channel 124. A through hole 34 is provided at the conical tip of the converging part 32, which is precisely located at the axial center position of the outer pipe 11. The low-temperature fluid converges towards the middle of the outer pipe 11 under the guidance of the inner surface of the converging part 32 and finally discharges through the through hole 34. Through this setting, the flow of part of the high-temperature fluid and the low-temperature fluid is effectively guided, realizing the replacement of the fluid position. At the same time, the turbulator 3 can also perform turbulator treatment on the fluid, significantly improving the heat exchange efficiency;

[0043] A plurality of mounting grooves 35 are provided on the turbulator 3. These mounting grooves 35 enable the turbulator 3 to be installed inside the outer pipe 11. During the installation process, simply insert the corresponding fin unit 12 into the mounting grooves 35, and then push the turbulator 3 to the predetermined position to complete the entire installation process. This installation method is not only simple and fast but also ensures the stability and reliability of the turbulator 3 inside the outer pipe 11.

Claims

1. A multi-stage inner fin high-efficiency heat exchange element, comprising: An outer tube (11) and a plurality of fin units (12), wherein the fin units (12) are evenly distributed circumferentially on the inner wall of the outer tube (11), and characterized in that the fin units (12) comprise: a first fin (121), wherein a tooth root of the first fin (121) is connected to an inner tube wall of the outer tube (11), and extends from the tube wall of the outer tube (11) toward the tube center of the outer tube (11); A plurality of second fins (122) are distributed on both sides of the first fin (121); two adjacent second fins (122) form a rectangular opening (123); a spacing is provided between the second fins (122) on opposite sides, forming a flow channel (125) connected to the rectangular opening (123); the length of the second fins (122) gradually increases from the center of the tube toward the tube wall; the second fins (122) are staggered in a direction from the center of the outer tube (11) toward the inner wall of the outer tube (11), so that the flow channel (125) and the rectangular opening (123) form a wavy fluid channel (124); The fin unit (12) is arranged in a spiral shape on the inner wall of the outer tube (11); The outer tube (11) is provided with a flow spoiler (3), the flow spoiler (3) comprising a diffuser (31) and a convergent portion (32), the diffuser (31) being provided with a flow channel (33) penetrating the convergent portion (32) and extending to the inside of the fluid channel (124), the high-temperature fluid being able to flow into the fluid channel (124) along the outer surface of the diffuser (31) and the guidance of the flow channel (33), the high-temperature fluid being able to flow along the outer surface of the diffuser (31) and the guidance of the flow channel (33), the diameter of one end of the convergent portion (32) being similar to the diameter of the outer tube (11) and being able to cover the fluid channel (124), the other end being provided with a through hole (34), the low-temperature fluid being able to converge toward the middle of the outer tube (11) under the guidance of the convergent portion (32); The spoiler (3) is provided with a plurality of mounting grooves (35), and the fin units (12) are inserted into the mounting grooves (35) for mounting the spoiler (3).

2. A multi-stage inner fin high-efficiency heat exchange element according to claim 1, characterized in that: The outer tube (11) comprises a plurality of spliced ​​tubes (111), the spliced ​​tubes (111) being combined into a complete outer tube (11) through a clamping structure (2), the fin unit (12) being arranged on the spliced ​​tubes (111), and the spliced ​​tubes (111) extending along an extension direction of the fin unit (12).

3. A multi-stage inner fin high-efficiency heat exchange element according to claim 2, characterized in that: The clamping structure (2) comprises a clamping slot (21) located on one side of the splicing tube (111) and a clamping block (22) located on the other side; the clamping slots (21) and the clamping blocks (22) on two adjacent splicing tubes (111) cooperate with each other; limiting slots (221) are further provided on both sides of the clamping block (22); and a limiting block (211) adapted to the limiting slot (221) is provided at the opening of the clamping slot (21).

4. The multi-stage inner fin high-efficiency heat exchange element according to claim 3, characterized in that: A sealing member (23) is provided between the clamping groove (21) and the clamping block (22) to improve the sealing effect at the joint.

5. The multi-stage inner fin high-efficiency heat exchange element according to claim 1, characterized in that: The wing root thickness of the first fin (121) and the second fin (122) are both greater than the wing top thickness.

6. The multi-stage inner fin high-efficiency heat exchange element according to claim 1, characterized in that: Rounded corners are provided at the tops of the first fin (121) and the second fin (122).

7. The multi-stage inner fin high-efficiency heat exchange element according to claim 1, characterized in that: The second fins (122) on adjacent sides are parallel to each other.

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