Tube-fin fin, heat exchanger, air conditioner

Abstract

The present invention provides a tube-fin fin, a heat exchanger, and an air conditioner. Among them, a tube-fin fin includes a fin body, one side of the fin body has a plurality of spherical protrusions, and the top of the spherical protrusion has a first groove, and the first groove extends from one side of the fin body toward the other side of the fin body. According to the tube-fin fin, heat exchanger, and air conditioner of the present invention, while forming longitudinal vortices in the air flow fluid to improve the heat transfer coefficient, the disturbance of the air flow flowing through the vicinity of the top of the spherical protrusion is increased, the thickness of the flow boundary layer of the air flow fluid is reduced, and the heat exchange performance of the heat exchanger is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat exchanger manufacturing, and particularly relates to a tube-fin fin, a heat exchanger, and an air conditioner. Background Art

[0002] Reducing the thermal resistance and pressure drop loss on the air side is a necessary way to improve the comprehensive performance of a heat exchanger, and the structural form of the fin is the main factor affecting the thermal resistance and pressure drop loss on the air side. Existing fin structures include forms such as window openings, slits, corrugations, and longitudinal vortex generators added to the fins. The purpose is to reduce the thermal resistance and pressure drop loss on the air side of the heat exchanger and improve the comprehensive performance of the heat exchanger. For example, in order to enhance the heat transfer efficiency between the air flow and the fin in the prior art, a spherical protrusion (abbreviated as a ball protrusion) protruding towards one side of the fin is disclosed on the windward side of the fin in the prior art. The surface of this ball protrusion is relatively smooth. When the air flow passes near it, the vortices in the flow field will be sucked away by the concave pit on the back of the ball protrusion, which can prevent the formation of larger vortices and reduce the air flow resistance. However, the inventor found through experiments and simulation studies that: the relatively smooth surface of the protruding side of the ball protrusion is prone to form a relatively thick laminar sublayer (laminar boundary layer), resulting in poor disturbance of the air flow by it. This structure is not conducive to improving the heat transfer efficiency on the protruding side. Based on this, the present invention is proposed to improve the heat transfer performance of the heat exchanger. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to provide a tube-fin fin, a heat exchanger, and an air conditioner, which can improve the disturbance of the air flow passing through the vicinity of the top of the ball protrusion while forming longitudinal vortices in the air flow fluid to increase the heat transfer coefficient, reduce the thickness of the flow boundary layer of the air flow fluid, and improve the heat transfer performance of the heat exchanger.

[0004] To solve the above problems, the present invention provides a tube-fin fin, including a fin body. One side of the fin body has a plurality of ball protrusions, and the top of the ball protrusion has a first groove, which extends from one side of the fin body towards the other side of the fin body.

[0005] Preferably, the first groove has a first axis of symmetry and a second axis of symmetry, and the first axis of symmetry is perpendicular to the second axis of symmetry.

[0006] Preferably, the first groove is rectangular, the length of the rectangle is L, the width of the rectangle is W, and the depth of the first groove is H. L = 1.7W, and / or, L = 1.7H.

[0007] Preferably, the plurality of ball protrusions are composed of N ball protrusion combination units, and the N ball protrusion combination units are evenly distributed on one side of the fin body.

[0008] Preferably, the spherical protrusion combination unit includes at least a first row of spherical protrusions, a second row of spherical protrusions, and a third row of spherical protrusions. The first row of spherical protrusions, the second row of spherical protrusions, and the third row of spherical protrusions are arranged parallel to and spaced from each other. The center distance between any two adjacent spherical protrusions in the second row of spherical protrusions is d2, and the center distance between any two adjacent spherical protrusions in the first row of spherical protrusions and the center distance between any two adjacent spherical protrusions in the third row of spherical protrusions are both d3, where 1 < d3 / d2 < 2.

[0009] Preferably, the center distance between the first row of spherical protrusions and the second row of spherical protrusions, and between the second row of spherical protrusions and the third row of spherical protrusions is d1. The fin body further includes tube holes, and the center distance between the spherical protrusions and the tube holes is p. Define the dimension in the direction parallel to the indicating direction of d1 of the spherical protrusion combination unit as the width m, where p / 4 < d1 < (p + m) / 4.

[0010] Preferably, a first flow guiding structure is provided on the circumferential side of the tube hole. The first flow guiding structure includes a first arc flow channel, a second arc flow channel, and a third arc flow channel that are sequentially connected end to end. The first arc flow channel and the second arc flow channel are externally tangent at the connection, and the second arc flow channel and the third arc flow channel are externally tangent at the connection.

[0011] Preferably, the arc radius of the first arc flow channel is R1, the arc radius of the second arc flow channel is R2, and the arc radius of the third arc flow channel is R3, where R1 = R3 and 3 ≥ R1 / R2 ≥ 2.5.

[0012] Preferably, a second flow guiding structure is further provided on the circumferential side of the tube hole. The structure of the second flow guiding structure is the same as that of the first flow guiding structure. Define any axis passing through the center of the tube hole and parallel to the air flow direction as the third symmetry axis. The second flow guiding structure is symmetric with the first flow guiding structure about the third symmetry axis, and the first arc flow channel in the first flow guiding structure is connected to the first arc flow channel in the second flow guiding structure, the third arc flow channel in the first flow guiding structure is connected to the third arc flow channel in the second flow guiding structure, and the first flow guiding structure and the second flow guiding structure form an envelope for the tube hole.

[0013] Preferably, the length direction of the first groove, the arrangement direction of the first row of spherical protrusions, and the air flow direction are parallel to each other.

[0014] Preferably, a plurality of tube holes are arranged at intervals in the air flow direction, a plurality of the first flow guiding structures are arranged continuously along the air flow direction, and a plurality of the second flow guiding structures are arranged continuously along the air flow direction.

[0015] The present invention also provides a heat exchanger, including the above-mentioned tube-fin fins.

[0016] The present invention also provides an air conditioner, which includes the heat exchanger described above.

[0017] For the fin-and-tube fin, heat exchanger, and air conditioner provided by the present invention, since the first groove is provided at the top of the ball protrusion, when the air flow passes through the top area of the ball protrusion, the structure of the first groove can disturb the air flow, thereby facilitating the reduction of the thickness of the flow boundary layer of the air flow fluid and improving the heat transfer performance of the heat exchanger. At the same time, the setting of the ball protrusion can form a longitudinal vortex in the air flow fluid (i.e., a vortex with the air flow direction as the rotation axis and flowing along the air flow direction), so that the heat transfer coefficient can be increased, that is, the heat transfer performance of the fin-and-tube fin is improved, and at the same time, the phenomenon of large resistance caused by the lateral direction of the air flow is prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic structural diagram of the fin-and-tube fin according to an embodiment of the present invention;

[0019] Figure 2 is Figure 1 a partial cross-sectional structural diagram of the ball protrusion in ;

[0020] Figure 3 is Figure 1 a partial enlarged view of A in ;

[0021] Figure 4 is the Nu-Re change relationship curve between the windowed fin in the prior art and the fin-and-tube fin in the invention;

[0022] Figure 5 is the f-Re change relationship curve between the windowed fin in the prior art and the fin-and-tube fin in the invention;

[0023] Figure 6 is the simulation result of the air flow velocity contour of the windowed fin in the prior art;

[0024] Figure 7 is the simulation result of the air flow velocity contour of the fin-and-tube fin in the invention;

[0025] Figure 8 is the simulation result of the air flow streamline of the fin-and-tube fin in the invention.

[0026] The reference numerals are represented as:

[0027] 1. fin body; 11. ball protrusion; 12. first groove; 13. ball protrusion combination unit; 14. tube hole; 15. first flow guiding structure; 151. first arc flow channel; 152. second arc flow channel; 153. third arc flow channel; 16. second flow guiding structure; 17. second groove. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] Referring to Figures 1 to 8 As shown, according to an embodiment of the present invention, a fin for a tube-fin heat exchanger is provided, including a fin body 1. One side of the fin body 1 has a plurality of spherical protrusions 11. The top of the spherical protrusion 11 has a first groove 12, and the first groove 12 extends from one side of the fin body 1 toward the other side of the fin body 1. In this technical solution, since the first groove 12 is provided at the top of the spherical protrusion 11, when the air flow passes through the top area of the spherical protrusion 11, the structure of the first groove 12 can disturb the air flow, which is beneficial to reducing the thickness of the flow boundary layer of the air flow fluid and improving the heat transfer performance of the heat exchanger. At the same time, the setting of the spherical protrusion 11 can form a longitudinal vortex in the air flow fluid (that is, a vortex with the air flow direction as the rotation axis and flowing along the air flow direction), so that the heat transfer coefficient, that is, the heat transfer performance of the fin for a tube-fin heat exchanger, can be improved, and at the same time, the phenomenon of large resistance caused by the transverse direction of the air flow can be prevented. Further, a second groove 17 is provided on the side of the spherical protrusion 11 opposite to the first groove 12, and the second groove 17 extends from the other side of the fin body 1 toward one side of the fin body 1. At this time, the setting of the second groove 17 can disturb the air flow on the other side of the fin body 1, which is beneficial to reducing the thickness of the flow boundary layer of the air flow fluid on the other side and improving the comprehensive heat transfer performance of the heat exchanger.

[0029] Preferably, the first groove 12 has a first symmetry axis and a second symmetry axis, and the first symmetry axis is perpendicular to the second symmetry axis, that is, the first groove 12 is preferably a groove structure with a regular shape, such as a circle, a square, a rectangle, an ellipse, etc. On the one hand, it is convenient for the processing and manufacturing of the first groove 12, and on the other hand, it is beneficial to organize and guide the flow direction of the heat exchange air flow. As a specific implementation manner, for example, the first groove 12 is a rectangle, the length of the rectangle is L, the width of the rectangle is W, and the depth of the first groove 12 is H, where L = 1.7W, and / or L = 1.7H. At this time, the length direction of the rectangle is parallel to the flow direction of the air flow (that is, the incoming flow direction), so as to guide the air flow. More specifically, the two wide sides of the first groove 12 are respectively located on the incoming flow side and the outgoing flow side of the air flow. The air flow flows into the first groove 12 from the incoming flow side and flows out of the first groove 12 from the outgoing flow side. During the process of flowing in and out of the first groove 12, the air flow will form a longitudinal vortex around the aforementioned first symmetry axis (the axis parallel to the long side), thereby realizing the function of disturbing the air flow, reducing the thickness of the flow boundary layer of the air flow fluid, and improving the heat transfer performance of the heat exchanger. More preferably, the wide side of the rectangle is arc-shaped, so that the rectangle is improved to the shape of a racetrack.

[0030] The heat transfer performance of the finned fins is directly related to the layout form of the plurality of the ball protrusions 11 on the fin body 1. Preferably, the plurality of the ball protrusions 11 are composed of N ball protrusion combination units 13, and the N (N is an integer not less than 2) ball protrusion combination units 13 are evenly distributed on one side of the fin body 1. That is, the present invention attempts to limit the arrangement form of the respective ball protrusions 11 on the fin body 1 and perform periodic arrangement on the fin body 1 in the form of N ball protrusion combination units 13.

[0031] Specifically, the ball protrusion combination unit 13 at least includes a first row of ball protrusions, a second row of ball protrusions, and a third row of ball protrusions. It can be understood that each of the first row of ball protrusions, the second row of ball protrusions, and the third row of ball protrusions is provided with a plurality of ball protrusions 11. As Figure 1 shown, a dotted line frame encloses a ball protrusion combination unit 13 in the figure, and in Figure 1 the shown fin body, there are a total of 4 ball protrusion combination units 13 thereon. The first row of ball protrusions, the second row of ball protrusions, and the third row of ball protrusions are arranged in parallel at intervals. The center distance between any two adjacent ball protrusions 11 in the second row of ball protrusions is d2, and the center distance between any two adjacent ball protrusions 11 in the first row of ball protrusions and the center distance between any two adjacent ball protrusions 11 in the third row of ball protrusions are both d3, and 1 < d3 / d2 < 2. In this technical solution, by limiting the correlation between d2 and d3, the respective ball protrusions in the first row of ball protrusions and the respective ball protrusions in the second row of ball protrusions are staggered, and the respective ball protrusions in the third row of ball protrusions and the respective ball protrusions in the second row of ball protrusions are also staggered, ensuring that the row of ball protrusions (d3) close to the tube hole is sparser than the ball protrusions in the middle row (d2), so as to reduce the resistance at the position close to the tube hole.

[0032] Preferably, the center distance between the first row of ball protrusions and the second row of ball protrusions and between the second row of ball protrusions and the third row of ball protrusions is d1. The fin body 1 further includes tube holes 14, and the center distance between two adjacent tube holes 14 is p. Define the dimension in the direction parallel to the indication direction of the ball protrusion combination unit 13 and d3 as the width m, and p / 4 < d1 < (p + m) / 4. In this way, it can be ensured that d1 is wide enough to reduce the flow resistance, and at the same time, it is limited that it will not be too wide, thereby preventing the phenomenon that the ball protrusions close to the tube holes 14 are difficult to process.

[0033] Preferably, a first flow guiding structure 15 is provided on the circumferential side of the hole of the pipe hole 14. The first flow guiding structure 15 includes a first arc-shaped flow channel 151, a second arc-shaped flow channel 152, and a third arc-shaped flow channel 153 that are connected end to end in sequence. The first arc-shaped flow channel 151 and the second arc-shaped flow channel 152 are externally tangent at the connection, and the second arc-shaped flow channel 152 and the third arc-shaped flow channel 153 are externally tangent at the connection. The second arc-shaped flow channel 152 in the first flow guiding structure 15 is connected to the first arc-shaped flow channel 151 and the third arc-shaped flow channel 153 in an externally tangent manner respectively, so that the flow channel of the first flow guiding structure 15 is a smooth curve, and there is no sharp corner structure in the flow channel, which can guide the air flow to flow smoothly along the outer wall of the flow channel (that is, the side wall of the flow channel away from the pipe hole 14, as Figure 8 can be seen from the air flow streamline simulation diagram in, the wall attachment streamline density of the outer wall is much greater than that of the inner wall streamline) and greatly reduce the fluid separation phenomenon at the tail of the round pipe (that is, the round copper pipe or round aluminum pipe passing through the pipe hole 14), so as to reduce the pressure drop loss around the pipe hole. Since there is no sharp corner structure in the air flow channel, the noise of the air flow is relatively small.

[0034] Furthermore, the arc radius of the first arc-shaped flow channel 151 is R1, the arc radius of the second arc-shaped flow channel 152 is R2, and the arc radius of the third arc-shaped flow channel 153 is R3, and R1 = R3, so that the first arc-shaped flow channel 151 and the third arc-shaped flow channel 153 are symmetric about a radial axis of the through pipe hole 14, and 3≥R1 / R2≥2.5, thereby ensuring that the air flow can flow closely along the flow guiding structure.

[0035] Preferably, a second flow guiding structure 16 is further provided on the circumferential side of the hole of the tube hole 14. The structure of the second flow guiding structure 16 is the same as that of the first flow guiding structure 15. Any axis passing through the center of the hole of the tube hole 14 and parallel to the air flow direction is defined as the third symmetry axis. The second flow guiding structure 16 and the first flow guiding structure 15 are symmetrical about the third symmetry axis. The first arc-shaped flow channel 151 in the first flow guiding structure 15 is communicated with the first arc-shaped flow channel 151 in the second flow guiding structure 16. The third arc-shaped flow channel 153 in the first flow guiding structure 15 is communicated with the third arc-shaped flow channel 153 in the second flow guiding structure 16. The first flow guiding structure 15 and the second flow guiding structure 16 form an envelope for the tube hole 14. It can be understood that the second flow guiding structure 16 also includes a first arc-shaped flow channel 151, a second arc-shaped flow channel 152, and a third arc-shaped flow channel 153 that are sequentially connected end to end. A plurality of the tube holes 14 are arranged at intervals in the air flow direction. A plurality of the first flow guiding structures 15 are continuously arranged along the air flow direction. A plurality of the second flow guiding structures 16 are continuously arranged along the air flow direction. Thus, the first flow guiding structure 15 and the second flow guiding structure 16 form a structure that is symmetrical about the third symmetry axis. The first flow guiding structure 15 and the second flow guiding structure 16 may include multiple groups of the first arc-shaped flow channel 151, the second arc-shaped flow channel 152, and the third arc-shaped flow channel 153 that are periodically reproduced along the air flow direction, so as to form a undulating flow guiding structure on both sides of the tube hole 14. This structure can guide the air flow to flow smoothly along the inner wall of the structure, greatly reducing the fluid separation phenomenon at the tail of the circular tube, so as to reduce the pressure drop loss around the tube hole.

[0036] Preferably, the length direction of the first groove 12, the arrangement direction of the first row of ball protrusions, and the air flow direction are parallel to each other. In this way, the effects of the first groove 12 and the first row of ball protrusions on generating longitudinal vortices, effectively reducing the thickness of the laminar boundary layer, and improving the heat transfer coefficient and efficiency can be optimized, while the occurrence of transverse vortices is reduced as much as possible, ensuring that the air flow resistance of the transverse vortices is reduced while reducing the thickness of the laminar boundary layer and improving the heat transfer coefficient and efficiency.

[0037] In order to further verify the comprehensive heat transfer effect of the tube fin designed by the present invention, the inventor conducted a comparative experiment (including simulation) on the windowed fin in the prior art and the tube fin of the present invention:

[0038] The theoretical basis is:

[0039] The Reynolds number Re formula is:

[0040]

[0041] The Nusselt number Re formula is:

[0042]

[0043] The formula for the resistance factor f is as follows:

[0044]

[0045] In the above formulas: ρ is the density; D is the characteristic dimension; μ is the dynamic viscosity of the fluid; U is the average flow velocity at the minimum cross-section; Ac is the minimum flow area; A 0 is the total heat transfer area; λ is the thermal conductivity; ΔP is the pressure difference of the air flow at the inlet and outlet; h is the convective heat transfer coefficient. For the above physical parameters, their measurement units can all adopt the international standard units.

[0046] (1) Comparative test on the heat transfer performance of fins

[0047] This test is obtained by acquiring the Reynolds number Re and Nusselt number Nu of the test objects (the windowed fins and the tube-fin fins of the present invention), and fitting the variation relationship between Nu and Re. The results are as Figure 4 shown. It can be seen through Figure 4 that within the range of Re from 500 to 2500, the Nu corresponding to the tube-fin fins of the present invention is greater than that of the windowed fins in the prior art (on average 20% better than the existing windowed fins), indicating that the tube-fin fins of the present invention have good heat transfer performance.

[0048] (2) Airflow pressure loss test

[0049] This test is obtained by acquiring the Reynolds number Re and resistance factor f of the test objects (the windowed fins and the tube-fin fins of the present invention), and fitting the variation relationship between f and Re. The results are as Figure 5 shown. It can be seen through Figure 5 that within the range of Re from 500 to 2500, the resistance factor f corresponding to the tube-fin fins of the present invention is smaller than that of the windowed fins in the prior art, indicating that the tube-fin fins of the present invention have less resistance and smaller pressure drop loss (on average 40% smaller than the existing windowed fins).

[0050] (3) Simulation test on the comprehensive heat transfer performance of fins

[0051] Figure 6 is the simulation result of the air flow velocity contour map of the windowed fins in the prior art, Figure 7 and Figure 6 is the simulation result of the air flow velocity contour map of the tube-fin fins of the present invention. It can be seen that the present invention designs a undulating flow guiding structure around the tube holes 14, and the vortex areas ( Figure 7 the framed parts in

[0052] According to an embodiment of the present invention, there is also provided a heat exchanger, including the above-mentioned finned tubes.

[0053] According to an embodiment of the present invention, there is also provided an air conditioner, including the above-mentioned heat exchanger.

[0054] It is easily understood by those skilled in the art that, on the premise of no conflict, the above-mentioned advantageous ways can be freely combined and superimposed.

[0055] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention. The above is only the preferred implementation manner of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, several improvements and modifications can be made without departing from the technical principle of the present invention, and these improvements and modifications should also be regarded as within the protection scope of the present invention.

Claims

1. A tube-fin fin, characterized in that, it includes a fin body (1), one side of the fin body (1) has a plurality of ball protrusions (11), the top of the ball protrusions (11) has a first groove (12), and the first groove (12) extends from one side of the fin body (1) towards the other side of the fin body (1); a plurality of the ball protrusions (11) form N ball protrusion combination units (13), and the N ball protrusion combination units (13) are evenly distributed on one side of the fin body (1); the ball protrusion combination unit (13) at least includes a first row of ball protrusions, a second row of ball protrusions, and a third row of ball protrusions, the first row of ball protrusions, the second row of ball protrusions, and the third row of ball protrusions are arranged parallel to each other at intervals, the center distance between any two adjacent ball protrusions (11) in the second row of ball protrusions is d2, and the center distance between any two adjacent ball protrusions (11) in the first row of ball protrusions and the center distance between any two adjacent ball protrusions (11) in the third row of ball protrusions are both d3, 1 < d3 / d2 < 2; the first groove (12) has a first axis of symmetry and a second axis of symmetry, and the first axis of symmetry is perpendicular to the second axis of symmetry.

2. The tube-fin fin according to claim 1, characterized in that, the first groove (12) is rectangular, the length of the rectangle is L, the width of the rectangle is W, and the depth of the first groove (12) is H, L = 1.7W, and / or, L = 1.7H.

3. The tube-fin fin according to claim 1, characterized in that, the center distance between the first row of ball protrusions and the second row of ball protrusions, and between the second row of ball protrusions and the third row of ball protrusions is d1, and the fin body (1) also includes tube holes (14). The center distance between two adjacent tube holes (14) in the direction parallel to the indicated direction of d1 is p. Define the size of the ball protrusion combination unit (13) in the direction parallel to the indicated direction of d3 as the width m, p / 4 < d1 < (p + m) / 4.

4. The tube-fin fin according to claim 3, characterized in that, a first flow guiding structure (15) is provided on the circumferential side of the tube hole (14). The first flow guiding structure (15) includes a first arc flow channel (151), a second arc flow channel (152), and a third arc flow channel (153) connected end to end in sequence. The first arc flow channel (151) and the second arc flow channel (152) are externally tangent at the connection, and the second arc flow channel (152) and the third arc flow channel (153) are externally tangent at the connection.

5. The tube-fin fin according to claim 4, characterized in that, the arc radius of the first arc flow channel (151) is R1, the arc radius of the second arc flow channel (152) is R2, and the arc radius of the third arc flow channel (153) is R3, R1 = R3, 3 ≥ R1 / R2 ≥ 2.

5.

6. The tube-fin fin according to claim 4, characterized in that, A second flow guiding structure (16) is further provided on the circumferential side of the hole of the pipe hole (14). The structure of the second flow guiding structure (16) is the same as that of the first flow guiding structure (15). Any axis passing through the center of the hole of the pipe hole (14) and parallel to the air flow direction is defined as the third symmetry axis. The second flow guiding structure (16) is symmetric with the first flow guiding structure (15) about the third symmetry axis. The first arc-shaped flow channel (151) in the first flow guiding structure (15) is communicated with the first arc-shaped flow channel (151) in the second flow guiding structure (16). The third arc-shaped flow channel (153) in the first flow guiding structure (15) is communicated with the third arc-shaped flow channel (153) in the second flow guiding structure (16). The first flow guiding structure (15) and the second flow guiding structure (16) form an envelope for the pipe hole (14).

7. The tube-fin fin according to claim 6, characterized in that, the length direction of the first groove (12), the arrangement direction of the first ball protrusion row, and the air flow direction are parallel to each other.

8. The tube-fin fin according to claim 6, characterized in that, a plurality of the pipe holes (14) are arranged at intervals in the air flow direction. A plurality of the first flow guiding structures (15) are arranged continuously along the air flow direction. A plurality of the second flow guiding structures (16) are arranged continuously along the air flow direction.

9. A heat exchanger includes a tube-fin fin, characterized in that, the tube-fin fin is the tube-fin fin according to any one of claims 1 to 8.

10. An air conditioner includes a heat exchanger, characterized in that, the heat exchanger is the heat exchanger according to claim 9.

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