Heat exchange tube and heat exchanger

Abstract

This invention provides a heat exchange tube and a heat exchanger. The heat exchange tube includes a tube body, an outer fin structure, and an inner rib structure. The heat exchange tube and heat exchanger provided by this invention have an outer fin structure on the outer wall of the tube body. This outer fin structure disturbs the fluid flowing through the outer wall of the tube body, causing the fluid to drip off the outer fin structure. This avoids the problem of fluid accumulating on the lower side of the tube body due to gravity within the channels defined by the outer fin structure, and also avoids fluid bridging between adjacent outer fin structures that could submerge the heat exchange area, thereby improving the external heat exchange efficiency of the heat exchange tube. Furthermore, an inner rib structure is provided on the inner wall of the tube body, forming a first spiral flow channel and a second spiral flow channel. This secondary disturbance increases the fluid ripple at the inner wall of the tube body. The outer fin structure and the inner rib structure enhance heat exchange in the heat exchange tube, thereby effectively improving the heat exchange efficiency of the heat exchange tube.

Description

Technical Field

[0001] This invention relates to the field of heat exchange structure technology, and in particular to a heat exchange tube and a heat exchanger. Background Technology

[0002] In the refrigeration and air conditioning industry, horizontal condensers have experienced rapid development due to their compact structure and wide applicability. High efficiency, energy saving, and the replacement of old refrigerants remain the main research directions. As one of the four major components of a chiller unit, the heat exchange performance of the horizontal condenser significantly affects the unit's energy efficiency. High-efficiency heat exchange tubes are key heat exchange and pressure-bearing components in the condenser; their heat exchange performance greatly influences the heat exchanger's performance, and consequently, the unit's performance.

[0003] In actual operation, the high-efficiency heat exchanger tubes operate with single-phase flow heat transfer inside (the medium inside the tube is generally water), while the outside is a two-phase flow heat transfer process (the refrigerant outside the tube is R134a, R1233zd(E), etc.). High-efficiency heat exchanger tubes are generally divided into external and internal structures (due to the use of copper with high thermal conductivity, the tube wall thermal resistance is very small, accounting for about 3%), and a comprehensive study is conducted using thermal resistance analysis methods. During use, it was found that the main thermal resistance changes depending on whether it is outside or inside the tube. For example, inside the tube, when the Reynolds number decreases, the heat transfer on the inner side deteriorates, and the main thermal resistance shifts from the outer side to the inner side, thus reducing the overall heat transfer coefficient of the heat exchanger tube. Outside the tube, as the heat flux density increases, the condensation heat transfer coefficient shows a decreasing trend. This is mainly because at high heat flux densities, the condensate volume increases, leading to a thicker liquid film.

[0004] To address this issue, current methods mainly involve modifying the internal structure of the heat exchanger tubes to enhance heat transfer, such as creating grooves on the inner wall or adding various fins. However, the problem of low heat exchange efficiency still exists. Summary of the Invention

[0005] In order to solve the technical problem of low heat exchange efficiency in the existing heat exchange tube structure, a heat exchange tube and heat exchanger are provided in which an outer fin structure is provided on the outer wall of the heat exchange tube and an inner rib structure is provided on the inner wall of the heat exchange tube to improve the heat exchange efficiency.

[0006] A heat exchange tube, comprising:

[0007] tube body;

[0008] An outer wing structure is disposed on the outer wall of the tube body, and the outer wing structure forms at least one outflow channel on the outer wall of the tube body;

[0009] An inner rib structure is provided on the inner wall of the tube body, and the inner rib structure forms a first inner spiral flow channel on the inner wall of the tube body. The inner rib structure has flow grooves, and all the flow grooves are interconnected to form a second inner spiral flow channel on the inner wall of the tube body.

[0010] The outer wing structure includes multiple outer wing protrusions, all of which are distributed on the outer wall of the tube along multiple straight lines parallel to the central axis of the tube. An outer flow channel is formed between all the outer wing protrusions on two adjacent straight lines.

[0011] There is a first gap between two adjacent outer wing protrusions on the same straight line. The outer wing protrusions on two adjacent straight lines are staggered. All the first gaps are connected to form an outer spiral flow channel, and the outer spiral flow channel constitutes another outer flow channel.

[0012] The outer wing protrusion has a flow guiding surface, which forms part of the side surface of the outer spiral flow channel.

[0013] The plane containing the flow guide surface forms an angle with the central axis of the tube body, and the angle of the angle is equal to the angle of the helix of the outer spiral flow channel.

[0014] Along the direction away from the tube body, the cross-sectional area of ​​the outer wing protrusion gradually decreases.

[0015] The cross-section of the outer wing protrusion is triangular, quadrilateral, or rectangular.

[0016] The outer wing protrusion includes a first outer wing protrusion and a second outer wing protrusion. The height of the first outer wing protrusion is greater than the height of the second outer wing protrusion, and the first outer wing protrusion and the second outer wing protrusion are staggered.

[0017] The height h1 of the first outer wing protrusion has a value range of 0.1mm≤h1≤2.0mm; the height h2 of the second outer wing protrusion has a value range of 0.1mm≤h2≤1.8mm; where h1≠h2.

[0018] The inner rib structure includes multiple inner rib protrusions, all of which are arranged on the inner wall of the tube in a spiral manner, and all the inner ribs on the same spiral line together form a first inner spiral flow channel.

[0019] There is a gap between two adjacent inner rib protrusions on the same spiral line, and the gap forms the flow groove.

[0020] The bottom surface of the second inner spiral channel is recessed to form a groove structure.

[0021] The depth h3 of the groove structure has a numerical range of 0.01mm ≤ h3 ≤ 0.35mm.

[0022] The spiral angle α of the first inner spiral channel is in the range of 20°≤α≤75°; and / or, the spiral angle β of the second inner spiral channel is in the range of 85°<β≤90°, and β≠α.

[0023] The height h4 of the inner rib structure has a numerical range of 0.1mm ≤ h4 ≤ 0.85mm.

[0024] The pitch w1 of the second inner spiral channel has a value range of 0.35mm≤w1≤2.5mm; the pitch w2 of the outer spiral channel has a value range of 0.35≤w2≤2.5mm; the relationship between the pitch w2 of the outer spiral channel and the pitch w1 of the second inner spiral channel is: w2=(1 / 4~2)w1.

[0025] The cross-section of the trench structure is an inverted trapezoid, triangle, or rectangle.

[0026] A heat exchanger comprising the heat exchange tubes described above.

[0027] The heat exchange tube and heat exchanger provided by this invention have an outer fin structure on the outer wall of the tube body. The outer fin structure disturbs the fluid flowing through the outer wall of the tube body, causing the fluid to drip off the outer fin structure. This avoids the problem of fluid accumulating on the lower side of the tube body due to gravity in the channels defined by the outer fin structure. It also avoids fluid bridging between adjacent outer fin structures, which would flood the heat exchange area, thereby improving the heat exchange efficiency outside the tube. Furthermore, an inner rib structure is provided on the inner wall of the tube body, forming a first spiral flow channel and a second spiral flow channel. This secondary disturbance of the fluid flowing through the inside of the tube body increases the fluctuation of the fluid at the inner wall of the tube body, thereby thinning the flow boundary layer, disrupting the temperature boundary layer, and enhancing the heat exchange inside the tube. At the same time, the heat exchange tube is enhanced by the outer fin structure and the inner rib structure, thereby effectively improving the heat exchange efficiency of the heat exchange tube. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the heat exchange tube provided in an embodiment of the present invention;

[0029] Figure 2 A cross-sectional view of a heat exchange tube provided in an embodiment of the present invention;

[0030] Figure 3 This is another cross-sectional view of the heat exchange tube provided in an embodiment of the present invention;

[0031] Figure 4 This is another cross-sectional view of the heat exchange tube provided in an embodiment of the present invention;

[0032] Figure 5 A schematic diagram of the inner cross-section of the heat exchange tube provided in an embodiment of the present invention;

[0033] Figure 6 A comparison curve of heat transfer coefficients for heat exchange tubes with different outer fin heights provided in an embodiment of the present invention;

[0034] Figure 7 A comparison curve of the heat transfer coefficients of the heat exchange tube with the heat exchange tube of the prior art provided in the embodiments of the present invention.

[0035] Figure 8 A comparison curve of heat transfer coefficients at different helical angles in the first inner helical flow channel of the heat exchange tube provided in an embodiment of the present invention;

[0036] Figure 9 A comparison curve of heat transfer coefficients at different heights of the inner rib protrusions of the heat exchange tube provided in an embodiment of the present invention.

[0037] In the picture:

[0038] 1. Tube body; 2. Outer wing structure; 3. Inner rib structure; 11. First inner spiral flow channel; 12. Second inner spiral flow channel; 21. First outer wing protrusion; 22. Second outer wing protrusion; 31. Inner rib protrusion; 32. Groove structure. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0040] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0041] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate for the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0042] It should be noted that in the description of this invention, terms such as "upper," "lower," "left," "right," "inner," and "outer," indicating directional or positional relationships, are based on the directional or positional relationships shown in the accompanying drawings. These are merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0043] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection, an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0044] In existing technologies, to improve the heat exchange efficiency of heat exchange tubes, modifications are typically made to either the inner or outer wall of the tube. For the inner wall, a common approach is the use of two-dimensional internal ribs. These ribs increase the heat exchange area and enhance turbulence, disrupting the flow boundary layer. However, the effect of a single threaded internal rib structure on primary flow turbulence within the tube is limited, especially at low flow velocities. Current technologies often adjust the structural parameters of the threaded internal ribs to enhance turbulence and promote heat transfer, but the enhancement effect is ultimately limited. For the outer wall, the condensation heat transfer coefficient decreases with increasing heat flux density. This is primarily because under film condensation conditions, the condensed liquid adheres to the surface of the heat exchange tube and flows along the channels between the fins and along the sides of the fins. The condensate covers the outer surface of the heat exchange tube, forming a liquid film that becomes the main thermal resistance. This thermal resistance hinders direct contact between the condensate film and the steam and the tube wall; the thicker the liquid film, the greater the thermal resistance and the worse the condensation heat transfer effect. In other words, under the condition of film condensation outside the tube, the condensed liquid adheres to the surface of the heat exchange tube and flows along the channels between the fins and on both sides of the fins. The condensate covers the outer surface of the heat exchange tube, forming a liquid film, which becomes the main thermal resistance. This heat transfer resistance hinders the direct contact between the condensate film and the steam and the tube wall. The thicker the liquid film, the greater the thermal resistance and the worse the condensation heat transfer effect. Therefore, to further improve the condensation heat transfer coefficient, it is necessary to further thin the condensate film and promote the rapid drainage of the condensate. To this end, this application provides the following... Figures 1 to 9 The heat exchange tube shown includes: a tube body 1; an outer fin structure 2, which is disposed on the outer wall of the tube body 1 and forms an outer flow channel on the outer wall of the tube body 1; and an inner rib structure 3, which is disposed on the inner wall of the tube body 1 and forms a first inner spiral flow channel 11 on the inner wall of the tube body 1. The inner rib structure 3 has flow grooves formed on it, and all the flow grooves are interconnected to form a second inner spiral flow channel 12 on the inner wall of the tube body 1. On the outer wall of the tube body 1, there is an outer fin structure 2. The outer fin structure 2 disturbs the fluid flowing through the outer wall of the tube body, causing the fluid to drip off the outer fin structure 2. This avoids the problem of the fluid accumulating on the lower side of the tube body 1 due to gravity in the channel defined by the outer fin structure 2. It also avoids the fluid bridging phenomenon between adjacent outer fin structures 2, which would flood the heat exchange area, thereby improving the heat exchange efficiency outside the tube. In addition, an inner rib structure 3 is set on the inner wall of the tube body 1, forming a first spiral flow channel and a second spiral flow channel. This secondary turbulence of the fluid flowing through the inside of the tube body 1 increases the fluctuation of the fluid at the inner wall surface of the tube body 1, thereby thinning the flow boundary layer, destroying the temperature boundary layer, and enhancing the heat exchange inside the tube. At the same time, the outer fin structure 2 and the inner rib structure 3 enhance the heat exchange of the heat exchange tube, thereby effectively improving the heat exchange efficiency of the heat exchange tube.

[0045] Specifically, the outer fin structure 2 includes multiple outer fin protrusions. All the outer fin protrusions are distributed on the outer wall of the tube body 1 along multiple straight lines parallel to the central axis of the tube body 1, and an outer flow channel is formed between all the outer fin protrusions on two adjacent straight lines. The use of the outer fin protrusions allows the heat exchange tube of this application to have two more surfaces compared to the heat exchange tubes of the prior art. The difference in the curvature radius of the condensate is greater than that of the original structure, thus increasing the surface tension gradient, thinning the liquid film, and reducing thermal resistance. Furthermore, the condensate is easily disturbed during the flow process and drips from the side of the outer fin protrusions. It cannot accumulate on the lower side of the heat exchange tube along the direction of gravity in the channel between the two outer fin protrusions. Moreover, the straight flow channel formed by all the outer fin protrusions on two adjacent straight lines allows the fluid adhering to the outer wall of the tube body 1 to flow in a straight line along the straight flow channel when the fluid flows through the outside of the tube body 1, thereby ensuring smooth fluid flow and further preventing the formation of condensate between the outer fin protrusions, reducing the thickness of the condensate film, thereby reducing thermal resistance and improving the heat exchange efficiency outside the heat exchange tube.

[0046] The outer fin protrusion is integrally formed with the tube body 1, that is, the outer fin protrusion is formed by extruding the outer wall of the tube body 1, which reduces the thermal resistance between the outer fin protrusion and the tube body 1 and improves the heat exchange efficiency outside the heat exchange tube.

[0047] Furthermore, there is a first gap between two adjacent outer fin protrusions on the same straight line. The outer fin protrusions on two adjacent straight lines are staggered, and all the first gaps are connected to form an outer spiral flow channel, which constitutes another outer flow channel. When the fluid flows through the first gap, it will undergo a certain spiral flow, further increasing the turbulence of the fluid, ensuring that the condensate drips reliably from the surface of the outer fin protrusion, reducing the condensate film thickness, thereby reducing thermal resistance and improving the heat exchange efficiency outside the heat exchange tube.

[0048] The outer fin protrusion has a flow-guiding surface, which forms part of the side surface of the outer spiral flow channel. The flow-guiding surface guides the fluid, allowing it to flow reliably along the outer spiral flow channel. This further increases fluid turbulence, ensuring reliable dripping of condensate from the surface of the outer fin protrusion, reducing the condensate film thickness, thereby lowering thermal resistance and improving the heat exchange efficiency outside the heat exchange tube. Preferably, the plane containing the flow-guiding surface forms an angle with the central axis of the tube body 1, and this angle is equal to the helix angle of the outer spiral flow channel. That is, by utilizing the angle between the plane containing the flow-guiding surface and the central axis of the tube body 1, and the staggered arrangement of the outer fin protrusions on adjacent straight lines, all the outer fin protrusions can reliably form an outer spiral flow channel, improving the heat exchange efficiency outside the heat exchange tube.

[0049] Optionally, the cross-section of the outer fin protrusion is triangular, quadrilateral, or rectangular. Taking a quadrilateral as an example, the quadrilateral has a first edge and a second edge opposite to each other, and a third edge between the first edge and the second edge. The first edge forms part of the sidewall of the outer spiral flow channel on one side of the outer fin protrusion, and the second edge forms part of the sidewall of the outer spiral flow channel on the other side of the outer fin protrusion. When the fluid flows through the outer fin protrusion, it is diverted by the third edge, forming two parts of the flow. One part of the flow will flow along the first edge, and the other part will flow along the second edge, thereby ensuring that the fluid flowing through the outer fin protrusion can flow smoothly along the outer spiral flow channel, further increasing the turbulence of the fluid, ensuring reliable dripping of condensate from the surface of the outer fin protrusion, reducing the thickness of the condensate film, thereby reducing thermal resistance and improving the heat exchange efficiency outside the heat exchange tube.

[0050] Furthermore, along the direction away from the tube body 1, the cross-sectional area of ​​the outer fin protrusion gradually decreases. This increases the turbulence effect of the outer fin protrusion on the fluid flowing through the outer wall of the tube body 1. At the same time, as the cross-sectional area of ​​the outer fin protrusion changes, the turbulence-breaking effect of the outer fin protrusion increases, disrupting the fluid boundary layer and further improving the heat exchange efficiency outside the heat exchange tube.

[0051] After decades of development, complex condensation surfaces (commonly known as three-dimensional fins) have been developed and widely used. Three-dimensional fins not only increase the heat transfer area but also utilize the surface tension of the liquid refrigerant to thin the liquid film and promote condensate flow. However, in ordinary three-dimensional fins, when the refrigerant condensate condenses at the fin tip, the pressure difference between the liquid phases on both sides of the fin is relatively small, resulting in the condensate not thinning rapidly and significantly on the fin, thus failing to improve the performance of the heat exchange tube. Furthermore, in existing heat exchange tubes, after condensation occurs between two fins, the condensate flows downwards along the channel between the two fins under gravity, but accumulates at the bottom of the heat exchange tube under capillary force and stagnates circumferentially, affecting efficient heat exchange. Therefore, as an alternative implementation, the outer fin protrusions include a first outer fin protrusion 21 and a second outer fin protrusion 22. The height of the first outer fin protrusion 21 is greater than the height of the second outer fin protrusion 22, and the first outer fin protrusion 21 and the second outer fin protrusion 22 are staggered. By utilizing the first outer fin protrusion 21 and the second outer fin protrusion 22 with different heights, the disturbance of the condensate during the flow process can be further increased, and the surface tension of the liquid film can be changed, causing it to drip in a scattered manner and preventing it from forming a liquid film column at the bottom of the heat exchange tube. This reduces the possibility of bridging, thereby ensuring the heat exchange area outside the heat exchange tube and improving the heat exchange capacity outside the heat exchange tube.

[0052] Optionally, the height h1 of the first outer fin protrusion 21 is in the range of 0.1mm ≤ h1 ≤ 2.0mm. When the height h1 of the first outer fin protrusion 21 is < 0.1mm, the first outer fin protrusion 21 has little effect on the turbulence of the fluid and cannot change the surface tension of the liquid film. At this time, the heat exchange efficiency outside the heat exchange tube is low. When the height h1 of the first outer fin protrusion 21 is > 2.0mm, the height of the first outer fin protrusion 21 is too large, which is inconvenient to process. At the same time, the resistance to the fluid is too strong, which will affect the heat exchange efficiency outside the heat exchange tube. Therefore, only when the height h1 of the first outer fin protrusion 21 is within the range of 0.1mm ≤ h1 ≤ 2.0mm can the smooth flow of the fluid outside the heat exchange tube be guaranteed while ensuring the heat exchange efficiency outside the heat exchange tube.

[0053] Similarly, the height h2 of the second outer fin protrusion 22 is in the range of 0.1mm ≤ h2 ≤ 1.8mm. When the height h2 of the second outer fin protrusion 22 is < 0.1mm, the second outer fin protrusion 22 has little effect on the turbulence of the fluid and cannot change the surface tension of the liquid film. At this time, the heat exchange efficiency outside the heat exchange tube is low. However, when the height h2 of the second outer fin protrusion 22 is > 1.8mm, the height of the second outer fin protrusion 22 is too large, which is inconvenient to process. At the same time, the resistance to the fluid is too strong, which will affect the heat exchange efficiency outside the heat exchange tube. Therefore, only when the height h2 of the second outer fin protrusion 22 is within the range of 0.1mm ≤ h2 ≤ 1.8mm can the smooth flow of the fluid outside the heat exchange tube be guaranteed while ensuring the heat exchange efficiency outside the heat exchange tube. Meanwhile, in order to increase the disturbance of the condensate during the flow process, change the surface tension of the liquid film, and make it drip in a scattered manner so that it does not condense into a liquid film column at the bottom of the heat exchange tube, thereby reducing the possibility of bridging, it is necessary to make h1≠h2. This ensures that different height external fin protrusions are formed on the outer wall of the heat exchange tube, thus ensuring the heat exchange efficiency outside the tube.

[0054] Taking a heat exchange tube with an inner diameter of 19.05 mm and a thickness of 0.711 mm as an example, an outer fin protrusion is machined on the outside of the heat exchange tube, making the height of the outer fin protrusion 0.95 mm. Then, the outer fin protrusion is knurled to different degrees to form the first outer fin protrusion 21 and the second outer fin protrusion 22. The specific parts are shown in the table below:

[0055]

[0056] like Figure 6 As shown in the figure, the curve containing the triangle represents the flow velocity and heat transfer coefficient inside heat exchanger tube A; the curve containing the dot represents the flow velocity and heat transfer coefficient inside heat exchanger tube B. It can be seen from the figure that the smaller the height of the second outer fin protrusion 22, the higher the heat transfer efficiency of the heat exchanger tube.

[0057] To improve the heat exchange efficiency of the heat exchange tube, it is necessary to simultaneously enhance the internal heat exchange efficiency of the heat exchange tube. Therefore, the inner rib structure 3 includes multiple inner rib protrusions 31. All the inner rib protrusions 31 are arranged on the inner wall of the tube body 1 in at least one spiral line, and all the inner ribs on the same spiral line together form a first inner spiral flow channel 11. When the fluid flows inside the tube body 1, it flows along the first inner spiral flow channel 11 defined by the inner rib protrusions 31. At this time, the inner rib protrusions 31 turbulent the fluid, forming a turbulent primary flow, thinning the flow boundary layer, and disrupting the temperature boundary layer, thereby improving the heat exchange efficiency inside the heat exchange tube.

[0058] There is a gap between two adjacent inner rib protrusions 31 on the same helix, and the gap constitutes the flow channel. When the fluid flows through the inner rib protrusions 31, it is diverted by the inner rib protrusions 31. Part of the fluid flows along the first inner helical channel 11, while the other part flows within the gap between the channels and along the second inner helical channel 12 under the limitation of the gap. Since there is an intersection between the first inner helical channel 11 and the second inner helical channel 12, the fluid flowing in the first inner helical channel 11 and the fluid flowing in the second inner helical channel 12 will collide and merge, further increasing the turbulence of the fluid in the pipe, further thinning the flow boundary layer, destroying the temperature boundary layer, and enhancing the heat transfer efficiency in the pipe. Among them, the inner rib structure 3 is squeezed along the helical angle of the second inner helical channel 12, thereby dividing the inner rib structure 3 into multiple inner rib protrusions 31, so that the gap is formed between two adjacent inner rib protrusions 31.

[0059] Furthermore, a groove structure 32 is formed by recessing the bottom surface of the second inner spiral flow channel 12. That is, the bottom surface of the second inner spiral flow channel 12 continues to be squeezed outward, thereby further turbulenting the fluid flowing inside the second inner spiral flow channel 12, further increasing the fluctuation of the fluid inside the heat exchange tube on the inner wall surface, and further enhancing the heat exchange efficiency inside the heat exchange tube.

[0060] Preferably, the depth h3 of the groove structure 32 is in the range of 0.01mm ≤ h3 ≤ 0.35mm. When the depth h3 of the groove structure 32 is less than 0.01mm, the depth of the groove structure 32 is too small, resulting in insufficient turbulence of the fluid and an inability to increase the fluctuation of the fluid on the inner wall surface of the heat exchange tube. Conversely, when the depth h3 of the groove structure 32 is greater than 0.35mm, since the groove structure 32 is squeezed outward from the bottom surface of the second spiral flow channel, the depth of the groove structure 32 is too large while the wall thickness of the heat exchange tube is too small, reducing the structural strength of the heat exchange tube and failing to guarantee its structural reliability. Only when the depth h3 of the groove structure 32 is within the range of 0.01mm ≤ h3 ≤ 0.35mm can the groove structure 32 further turbulent the fluid flowing in the second inner spiral flow channel 12, further increasing the fluctuation of the fluid on the inner wall surface of the heat exchange tube and further enhancing the heat exchange efficiency inside the heat exchange tube.

[0061] Preferably, the spiral angle α of the first inner spiral channel 11 is in the range of 20°≤α≤75°. When the fluid flows through the first inner spiral channel 11, it will spiral along the spiral angle of the first inner spiral channel 11, such as... Figure 8 As shown, when the helix angle α is less than 20°, the resistance of the first inner spiral flow channel 11 to the fluid flow along the axial direction is too large, affecting the reliable flow of the fluid in the heat exchange tube. Conversely, when the helix angle α is greater than 75°, the resistance of the first inner spiral flow channel 11 to the fluid flow along the axial direction is too small, reducing the turbulence effect of the first inner spiral flow channel 11 and decreasing the heat exchange efficiency in the heat exchange tube. Only when the helix angle α of the first inner spiral flow channel 11 is within the range of 20°≤α≤75° can the first inner spiral flow channel 11 reliably turbulent the fluid while avoiding excessive resistance to the fluid flow along the axial direction, thus ensuring smooth fluid flow within the tube body 1. Figure 8 In this context, the helix angle θ represents the helix angle α of the first inner helix flow channel.

[0062] The spiral angle β of the second inner spiral flow channel 12 is in the range of 85° < β ≤ 90°. When the fluid flows through the second inner spiral flow channel 12, it will spiral along the spiral angle of the second inner spiral flow channel 12. When the spiral angle β is less than 85°, the resistance of the second inner spiral flow channel 12 to the flow of the fluid along the axial direction is too large, which affects the reliable flow of the fluid in the heat exchange tube. When the spiral angle β is greater than 90°, the spiral direction of the second inner spiral flow channel 12 is the same as the spiral direction of the first inner spiral flow channel 11, which cannot be achieved structurally. Only when the spiral angle β of the second inner spiral flow channel 12 is in the range of 85° < β ≤ 90° can the second inner spiral flow channel 12 reliably turbulent the fluid and ensure the reliable forming of the second inner spiral flow channel 12, thereby ensuring the smooth flow of the fluid in the tube body 1.

[0063] In order to improve the turbulence effect on the fluid flowing inside the pipe body 1, the helix angle α of the first inner spiral channel 11 should not be equal to the helix angle β of the second inner spiral channel 12. When the fluid in the first inner spiral channel 11 and the second inner spiral channel 12 collides, the resulting flow splitting is uneven and the splitting cannot completely cancel each other out, thereby achieving the purpose of reliably turbulenting the fluid.

[0064] Preferably, the height h4 of the inner rib structure 3 is in the range of 0.1mm ≤ h4 ≤ 0.85mm. For example... Figure 9 As shown, when the height h4 of the inner rib structure 3 is less than 0.1 mm, the turbulence effect of the inner rib structure 3 on the fluid is reduced, failing to ensure fluid flow along the first inner spiral channel 11, thus reducing the heat exchange efficiency within the heat exchange tube. Conversely, when the height h4 of the inner rib structure 3 is greater than 0.85 mm, the excessive protrusion of the inner rib structure 3 from the inner wall of the heat exchange tube severely affects fluid flow, resulting in excessive fluid resistance and hindering the tube's efficiency. Only when the height h4 of the inner rib structure 3 falls within the range of 0.1 mm ≤ h4 ≤ 0.85 mm can the inner rib structure 3 reliably turbulent the fluid while avoiding excessive fluid resistance, effectively improving the heat exchange efficiency within the heat exchange tube. Figure 9 In this context, H represents the height h4 of the inner rib structure 3.

[0065] The pitch w1 of the second inner spiral flow channel 12 is in the range of 0.35mm ≤ w1 ≤ 2.5mm. When the pitch w1 of the second inner spiral flow channel 12 is less than 0.35mm, the distance between adjacent inner rib protrusions 31 is too small, and the fluid cannot flow smoothly into the second inner spiral flow channel 12, that is, it cannot be turbulent by the second inner spiral flow channel 12, and the heat exchange efficiency inside the heat exchange tube cannot be improved. When the pitch w1 of the first inner spiral flow channel 11 is greater than 2.5mm, under the premise of the same heat exchange tube length, the width of the second inner spiral flow channel 12 is too large. In other words, if the pitch of the second inner spiral channel 12 through which the fluid flows axially is too small, the turbulence effect of the second inner spiral channel 12 on the fluid is reduced, and the heat exchange efficiency inside the heat exchange tube cannot be improved. Only when the pitch w1 of the second inner spiral channel 12 is in the range of 0.35mm≤w1≤2.5mm can the second inner spiral channel 12 reliably turbulent the fluid, and at the same time avoid excessive resistance to the fluid flow along the axial direction, thereby ensuring smooth fluid flow in the tube body 1 and ensuring the heat exchange efficiency of the heat exchange tube. Figure 7As shown, the curve marked with an asterisk represents the heat transfer coefficient of heat exchange tubes in the prior art, while the curve marked with a square represents the heat transfer coefficient of the heat exchange tube in this application. It is clear from the figure that the heat transfer coefficient of the heat exchange tube in this application is higher than that of the heat exchange tubes in the prior art under any flow rate conditions.

[0066] The pitch w2 of the outer spiral flow channel is in the range of 0.35mm ≤ w2 ≤ 2.5mm. When the pitch w2 is less than 0.35mm, the spacing between adjacent outer fin protrusions is too small, and the fluid cannot flow smoothly into the outer spiral flow channel, meaning it cannot be turbulent by the outer spiral flow channel, thus failing to improve the external heat exchange efficiency of the heat exchange tube. Conversely, when the pitch w2 is greater than 2.5mm, under the same heat exchange tube length, the width of the outer spiral flow channel is too large, meaning the flow... If the pitch of the outer spiral channel through which the body flows axially is too small, the turbulence effect of the outer spiral channel on the fluid will be reduced, and the heat exchange efficiency inside the heat exchange tube will not be improved. Only when the pitch w2 of the outer spiral channel is in the range of 0.35mm≤w2≤2.5mm can the outer spiral channel reliably turbulent the fluid, and at the same time avoid excessive resistance to the fluid flow along the axial direction, thereby ensuring the smooth flow of the fluid in the tube body 1 and ensuring the heat exchange efficiency of the heat exchange tube.

[0067] Preferably, the relationship between the pitch w2 of the outer spiral flow channel and the pitch w1 of the second inner spiral flow channel 12 is: w2 = (1 / 4 ~ 2)w1. That is, the pitch of the groove structure 32 is also w1, and at least part of the groove structure 32 can overlap with the outer spiral flow channel, thereby reducing the thickness of the tube body 1 between the bottom surface of the groove structure 32 and the bottom surface of the outer spiral flow channel while ensuring the structural strength of the heat exchange tube body 1, thereby further increasing the internal and external heat exchange efficiency of the heat exchange tube.

[0068] The cross-section of the groove structure 32 is an inverted trapezoid, triangle, or rectangle. The cross-section of the groove structure 32 is selected according to its width. While ensuring the structural strength of the heat exchange tube, the size of the groove structure 32 is increased as much as possible, thereby maximizing the heat transfer efficiency between the inside and outside of the heat exchange tube.

[0069] Example

[0070] The inner diameter of tube 1 is 22.23 mm, and the thickness of tube 1 is 1.09 mm. The outer surface of tube 1 is formed with knurling to create fins of varying heights, with the maximum height of the fins ranging from 0.7 mm to 1.0 mm. The inner surface of the tube is formed with multi-threaded extrusion to create inner rib protrusions 31, with a height h1 of 0.406 mm. The helix angle β of the second inner spiral flow channel 12 is 48°, and the depth h of the groove structure 32 is 0.105 mm. After testing, the heat exchange tube described above shows an improvement in heat exchange performance of approximately 12.5% ​​or more compared to the conventional internal thread heat exchange tube in the prior art, with an improvement of 7% on the outer surface.

[0071] A heat exchanger comprising the heat exchange tubes described above.

[0072] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A heat exchange tube, characterized in that: include: tube body(1); An outer wing structure (2) is disposed on the outer wall of the tube body (1), and the outer wing structure (2) forms at least one outflow channel on the outer wall of the tube body (1); An inner rib structure (3) is provided on the inner wall of the tube body (1), and the inner rib structure (3) forms a first inner spiral flow channel (11) on the inner wall of the tube body (1). A flow groove is formed on the inner rib structure (3), and all the flow grooves are interconnected to form a second inner spiral flow channel (12) on the inner wall of the tube body (1). The outer wing structure (2) includes multiple outer wing protrusions. All the outer wing protrusions are distributed on the outer wall of the tube body (1) along multiple straight lines parallel to the central axis of the tube body (1). An outer flow channel is formed between all the outer wing protrusions on two adjacent straight lines. There is a first gap between two adjacent outer wing protrusions on the same straight line. The outer wing protrusions on two adjacent straight lines are staggered. All the first gaps are connected to form an outer spiral flow channel. The outer spiral flow channel constitutes another outer flow channel. The outer wing protrusion includes a first outer wing protrusion (21) and a second outer wing protrusion (22). The height of the first outer wing protrusion (21) is greater than the height of the second outer wing protrusion (22), and the first outer wing protrusion (21) and the second outer wing protrusion (22) are staggered. The height h1 of the first outer wing protrusion (21) has a value range of 0.1mm≤h1≤2.0mm; the height h2 of the second outer wing protrusion (22) has a value range of 0.1mm≤h2≤1.8mm; where h1≠h2; The bottom surface of the second inner spiral channel (12) is recessed to form a groove structure (32). The spiral angle α of the first inner spiral channel (11) is in the range of 20°≤α≤75°; and / or, the spiral angle β of the second inner spiral channel (12) is in the range of 85°<β≤90°, and β≠α; The height h4 of the inner rib structure (3) has a numerical range of 0.1mm≤h4≤0.85mm; The pitch w1 of the second inner spiral channel (12) has a value range of 0.35mm≤w1≤2.5mm; the pitch w2 of the outer spiral channel has a value range of 0.35mm≤w2≤2.5mm; the relationship between the pitch w2 of the outer spiral channel and the pitch w1 of the second inner spiral channel (12) is: w2=(1 / 4~2)w1.

2. The heat exchange tube according to claim 1, characterized in that: The outer wing protrusion has a flow guiding surface, which forms part of the side surface of the outer spiral flow channel.

3. The heat exchange tube according to claim 2, characterized in that: The plane containing the flow guide surface has an angle with the central axis of the tube body (1), and the angle of the angle is equal to the angle of the spiral angle of the outer spiral flow channel.

4. The heat exchange tube according to any one of claims 1 to 3, characterized in that: Along the direction away from the tube body (1), the cross-sectional area of ​​the outer wing protrusion gradually decreases.

5. The heat exchange tube according to any one of claims 1 to 3, characterized in that: The cross-section of the outer wing protrusion is triangular or quadrilateral.

6. The heat exchange tube according to claim 1, characterized in that: The inner rib structure (3) includes a plurality of inner rib protrusions (31), all of which are arranged on the inner wall of the tube body (1) in a manner of at least one spiral line, and all of the inner rib protrusions (31) on the same spiral line together form a first inner spiral flow channel (11).

7. The heat exchange tube according to claim 6, characterized in that: There is a gap between two adjacent inner rib protrusions (31) on the same spiral line, and the gap forms the flow groove.

8. The heat exchange tube according to claim 1, characterized in that: The depth h3 of the groove structure (32) has a numerical range of 0.01mm≤h3≤0.35mm.

9. The heat exchange tube according to claim 1, characterized in that: The cross-section of the groove structure (32) is an inverted trapezoid, triangle or rectangle.

10. A heat exchanger, characterized in that: The heat exchange tube includes any one of claims 1 to 9.

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