Multi-stage inner fin efficient heat exchange element

Abstract

The invention provides a multi-stage inner fin efficient heat exchange element, and belongs to the technical field of heat exchange elements, the multi-stage inner fin efficient heat exchange element comprises an outer tube and a plurality of fin units, the fin units are uniformly and circumferentially distributed on the inner wall of the outer tube, each fin unit comprises a first fin, the tooth root of each first fin is connected with the inner tube wall of the outer tube, and the tooth root of each first fin is connected with the inner tube wall of the outer tube; the outer tube wall extends to the outer tube core to form the outer tube; the second fins are distributed on the two sides of the first fins, and every two adjacent second fins form a rectangular opening; by arranging the first fins and the second fins, the heat exchange area can be increased, so that the heat exchange efficiency is improved, a rectangular opening is formed between every two adjacent second fins, and a wavy fluid channel is formed by the rectangular openings and the flowing channels, so that fluid can swing to a larger extent, and the heat exchange efficiency is improved. Therefore, the thermal contact area between the fluid and the first fins and the second fins is increased, and the heat exchange efficiency is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of heat exchange elements, and in particular relates to a multi-stage inner wing high-efficiency heat exchange element. Background Art

[0002] In the field of heat exchange, the heat transfer efficiency of traditional bare tubes is difficult to meet the growing industrial demand. The heat transfer between the inner and outer wall fluids and the tube wall of bare tubes mainly relies on convection heat transfer, and the heat transfer coefficient is relatively low. In order to improve the heat transfer efficiency, the inner finned tube came into being. The inner finned tube greatly increases the heat transfer area by processing the fin structure on the inner surface of the tube. Compared with bare tubes, the inner finned tube can form a stronger disturbance of the fluid in the tube and thin the boundary layer, thereby significantly improving the heat transfer coefficient of the fluid in the tube and enhancing the overall heat exchange performance. This structural improvement has been widely used in heat exchangers in many industries such as chemical industry, energy, refrigeration, etc., effectively improving energy utilization efficiency and reducing equipment size and cost.

[0003] A Chinese patent with announcement number CN105444602A discloses a new type of inner finned tube for a boiler, which includes a cylindrical hollow outer tube, in which an aluminum insert is embedded, the insert consisting of two semicircular shell comb-like structures, small fins are also arranged on the comb tooth surface, the small fins on the comb teeth are fins of unequal height in the radial direction of the outer tube, the comb teeth of the two semicircular shell comb-like structures are staggered, the two ends of the two semicircular shell comb-like structures are connected to each other, and the comb teeth gradually become longer in the radial direction of the outer tube from the inlet to the outlet, or remain unchanged after gradually becoming longer to a certain length.

[0004] However, the above technical solution has an inner finned tube, and the contact area between the fins in the tube and the flowing medium is small, and the heat exchange area is small, which leads to a low thermal conductivity and low heat exchange efficiency, and cannot 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 inner fin high-efficiency heat exchange element, aiming to solve the problem that the heat exchange efficiency of the new inner fin tube for boilers in the prior art cannot meet the heat exchange requirements of high-temperature fluids and the heat exchange efficiency needs to be further improved.

[0006] To achieve the above object, the present invention provides the following technical solution: a multi-stage inner fin high-efficiency heat exchange element, comprising: an outer tube and a plurality of fin units, wherein the fin units are evenly distributed on the inner wall of the outer tube, and the fin units include: A first fin, wherein the tooth root of the first fin is connected to the inner tube wall of the outer tube and extends from the tube wall of the outer tube to the tube center of the outer tube; 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, forming a flow channel connected to the rectangular opening. The length of the second fins gradually increases from the center of the tube to the tube wall, and the second fins are staggered in the direction from the center of the outer tube to the inner wall of the outer tube, so that the flow channel and the rectangular opening form a wavy fluid channel.

[0007] 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.

[0008] A further technical solution of the present invention is that the outer tube includes a plurality of spliced ​​tubes, the spliced ​​tubes are combined into a complete outer tube through a clamping structure, the fin unit is arranged on the spliced ​​tubes, and the spliced ​​tubes extend along the extension direction of the fin unit.

[0009] A further technical solution of the present invention is that the card connection structure includes a card slot located on one side of the splicing tube and a card block located on the other side, the card slots and card blocks on two adjacent splicing tubes cooperate with each other, and limit slots are also provided on both sides of the card block, and a limit block adapted to the limit slot is provided at the opening of the card slot.

[0010] A further technical solution of the present invention is that a sealing member is provided between the card slot and the card block to improve the sealing effect at the joint.

[0011] A further technical solution of the present invention is that a spoiler is provided on the outer tube, and the spoiler includes a diffuser and a convergent portion, and the diffuser is provided with a flow channel that penetrates the convergent portion and extends to the inside of the fluid channel, and the high-temperature fluid can be guided into the fluid channel along the outer surface of the diffuser and the guide of the flow channel, and the diameter of one end of the convergent portion is similar to that of the outer tube and can cover the fluid channel, and a through hole is provided at the other end, and the low-temperature fluid converges to the middle of the outer tube under the guidance of the convergent portion.

[0012] A further technical solution of the present invention is that a plurality of mounting grooves are provided on the spoiler, and the fin units are inserted into the mounting grooves for mounting the spoiler.

[0013] A further technical solution of the present invention is that the wing root thickness of the first fin and the second fin are both greater than the wing top thickness.

[0014] A further technical solution of the present invention is that rounded corners are arranged at the wing tops of the first fin and the second fin.

[0015] A further technical solution of the present invention is that the second fins on adjacent sides are parallel to each other.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 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.

[0017] 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.

[0018] 3. By setting up seals, the sealing effect of the joints can be improved, effectively preventing fluid leakage.

[0019] 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

[0020] 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: Figure 1 It is a structural schematic diagram of the first embodiment of the present invention; Figure 2 It is a structural schematic diagram of the second embodiment of the present invention; Figure 3 It is a schematic diagram of the installation structure of the spoiler in a specific embodiment of the present invention; Figure 4 It is a structural schematic diagram of a spoiler in a specific embodiment of the present invention; 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.

[0021] 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. clamping groove; 211. limit block; 22. clamping block; 221. limit groove; 23. sealing member; 3. spoiler; 31. diffuser; 32. gathering portion; 33. flow channel; 34. through hole; 35. mounting groove. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] See also Figure 1-Figure 5 The present invention provides the following technical solution: a multi-stage inner fin high-efficiency heat exchange element, comprising a heat exchange tube body 1, on the outer surface of which a light tube is sleeved.

[0024] See also Figure 1 In Example 1, the heat exchange tube body 1 is composed of a cylindrical outer tube 11 and 16 fin units 12 evenly arranged along the circumference of the axis of the outer tube 11. The fin unit 12 extends along the length direction of the outer tube 11. The fin unit 12 and the outer tube 11 are both made of silicon aluminum alloy and manufactured through an integrated molding process. The fin unit 12 is arranged on the inner tube wall of the outer tube 11. The cross section of the fin unit 12 extends from the inner wall of the outer tube 11 to the tube center direction, which can increase the heat exchange area and thus significantly improve the heat exchange efficiency; The fin unit 12 is composed of an integrally formed first fin 121 and a plurality of second fins 122. The tooth root of the first fin 121 is connected to the inner tube wall of the outer tube 11, and the tooth top extends toward 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 adjacent sides are parallel to each other and together form a rectangular opening 123. Between two adjacent first fins 121, a certain distance is maintained between the second fins 122 on the opposite sides, thereby forming a flow channel 125 connected to the rectangular opening 123. It is worth noting that since the center of the outer tube 11 is far from the water flow, the temperature is relatively high, while the inner wall of the outer tube 11 is in close contact with the water flow and has a lower temperature. In order to prevent the second fin 122 from melting due to 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, which not only ensures the effective heat dissipation area of ​​the fin, but also greatly reduces the risk of melting the fin due to high temperature. In particular, in the central area 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; The second fins 122 on the opposite side are staggered in the direction from the center of the outer tube 11 to the inner wall of the outer tube 11. Such a design makes the rectangular openings 123 on the opposite side also present the characteristics of staggered distribution. Such a layout not only increases the distance between the wing tops of two adjacent second fins 122, effectively reducing the obstacles encountered by the fluid during the flow process, but also makes the flow channel 125 combined 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; Fillets are provided at the top of the first fin 121 and the second fin 122. This design is intended to reduce stress concentration and thus improve the overall structural strength. In addition, the thickness of the wing root is designed to be greater than the wing top, because the wing root, as the key connecting part between the fin and the outer tube 11, needs to withstand greater stress and pressure. Therefore, thicker wing roots can provide more stable mechanical support and enhance structural strength to ensure that the fins are not prone to falling off or damage during long-term use. Since the wing tip is far away from the base tube, the stress and pressure it is subjected to are relatively small. Therefore, we can appropriately reduce the thickness of the wing tip to improve the heat transfer performance, and at the same time, such a design will not have a significant impact on the overall mechanical strength.

[0025] See also Figure 2 In the second embodiment, different from the first embodiment, the fin units 12 are arranged on the inner wall of the outer tube 11 in a spiral shape and are evenly arranged along the circumference of the axis of the outer tube 11 to ensure that the spacing between adjacent fin units 12 remains consistent. This spirally distributed fin unit design 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 setting of the fin units 12 also makes the fluid channel 124 form a spiral distribution along the axis direction of the outer tube 11, which promotes the fluid to flow in a spiral shape along the fluid channel 124. Compared with axial flow, this flow mode effectively prolongs the residence time of the fluid on the fin unit 12, thereby providing more time for heat exchange.

[0026] Please continue to participate Figure 2In the third embodiment, the outer tube 11 is evenly divided into a plurality of spliced ​​tubes 111 along the circumferential direction. These spliced ​​tubes 111 are connected to each other through the clamping structure 2, so as to be combined into a complete outer tube 11 shape. Each spliced ​​tube 111 is installed with 1 to 4 fin units 12. In order to simplify the production process, the spliced ​​tube 111 extends along the extension direction of the fin unit 12. Specifically, if the fin unit 12 extends along the horizontal axis, the spliced ​​tube 111 can also extend along the horizontal axis parallel to the fin unit 12. If the fin unit 12 extends in a spiral manner, the spliced ​​tube 111 can extend along the spiral direction with the same pitch as the fin unit 12. Such a design not only ensures the integrity of the fin unit 12 after splicing, but also greatly improves the convenience of producing the spliced ​​tube 111 and the fin unit 12.

[0027] 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 splicing tube 111 and a clamping block 22 on the other side. The clamping grooves 21 and the clamping blocks 22 on two adjacent splicing tubes 111 match each other. By clamping the clamping blocks 22 into the clamping grooves 21, multiple splicing tubes 111 can be assembled. However, during the splicing process, when the number of splicing tubes 111 is large, if there is a lack of firm fixation between adjacent splicing tubes 111, the clamping blocks 22 may slip out of the clamping grooves 21. To solve this problem, limiting grooves 221 are designed on both sides of the clamping blocks 22, and limiting blocks 211 are provided at the opening of the clamping grooves 21. The mutual cooperation between the limiting grooves 221 and the limiting blocks 211 effectively limits the freedom of the clamping blocks 22 in the clamping grooves 21, so that the clamping blocks 22 can only slide along the inside of the clamping grooves 21, thereby avoiding the problem of splicing difficulties caused by the clamping blocks 22 accidentally slipping out of the clamping grooves 21 during the assembly process; A seal 23 is installed inside the card slot 21. Its main function is to ensure that the joints of the splicing tube 111 achieve a good sealing effect, thereby effectively preventing fluid leakage. The seal 23 used here is a vermiculite pad. This material has a unique property: under high temperature conditions, the vermiculite pad can expand. This expansion characteristic can not only enhance the fit between the seal 23 and the splicing tube 111, but also further enhance the sealing effect, ensuring that even under high temperature conditions, the fluid will not leak from the joints.

[0028] Please continue to participate Figure 3 and Figure 4 Since the temperature at the center of the outer tube 11 is relatively high, while the temperature at the inner wall is relatively low, the high temperature at the center is difficult to be effectively transferred to the surface of the fin unit 12, thereby reducing the heat exchange efficiency. In order to solve this problem, a spoiler 3 is provided at the center of the outer tube 11; The spoiler 3 is composed of a diffuser 31 and a convergent portion 32, and these two parts can be integrated by a sand casting process. On the diffuser 31, a flow channel 33 is designed to penetrate the convergent portion 32, and the outlet of the flow channel 33 extends to the inside of the fluid channel 124. The diffuser 31 is designed in a conical shell shape and is installed at the axial position of the outer tube 11, and its cone tip faces the direction of fluid flow. Such a layout enables the fluid to smoothly guide the high-temperature fluid to the fluid channel 124 along the outer surface of the diffuser 31 and the guide of the flow channel 33. Relatively speaking, the convergent portion 32 is designed to be a conical shell that matches the diffuser 31, and its cone tip faces In the direction of fluid flow, the diameter of the end of the gathering portion 32 away from the cone tip is close to the diameter of the outer tube 11. This design enables the gathering portion 32 to effectively cover the fluid channel 124. A through hole 34 is provided at the cone tip of the gathering portion 32. The through hole 34 is precisely located at the axial position of the outer tube 11. Under the guidance of the inner surface of the gathering portion 32, the low-temperature fluid converges to the middle of the outer tube 11 and is finally discharged through the through hole 34. Through this arrangement, the flow of part of the high-temperature fluid and the low-temperature fluid is effectively guided, and the displacement of the fluid position is realized. At the same time, the spoiler 3 can also perform a spoiler treatment on the fluid, which significantly improves the heat exchange efficiency. The spoiler 3 is provided with a plurality of mounting grooves 35, which enable the spoiler 3 to be installed inside the outer tube 11. During the installation process, it is only necessary to insert the corresponding fin unit 12 into the mounting groove 35, and then push the spoiler 3 to a predetermined position to complete the entire installation process. This installation method is not only simple and quick, but also ensures the stability and reliability of the spoiler 3 in the outer tube 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 the 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).

2. A multi-stage inner fin high-efficiency heat exchange element according to claim 1, characterized in that: The fin unit (12) is arranged in a spiral shape on the inner wall of the outer tube (11).

3. A multi-stage inner fin high-efficiency heat exchange element according to claim 1 or 2, 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).

4. The multi-stage inner fin high-efficiency heat exchange element according to claim 3, 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).

5. The multi-stage inner fin high-efficiency heat exchange element according to claim 4, 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.

6. The multi-stage inner fin high-efficiency heat exchange element according to claim 1, characterized in that: 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), so that high-temperature fluid can be guided 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 guided into the fluid channel (124), the convergent portion (32) having a diameter at one end close to that of the outer tube (11) and being able to cover the fluid channel (124), and a through hole (34) being provided at the other end, so that the low-temperature fluid is guided toward the middle of the outer tube (11) by the convergent portion (32).

7. The multi-stage inner fin high-efficiency heat exchange element according to claim 6, characterized in that: 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).

8. 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.

9. 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).

10. 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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