Wavy fin heat exchanger with oblique cutting

Abstract

This invention relates to the field of heat dissipation technology, specifically designing a slanted, wave-shaped finned heat exchanger, comprising a flat tube and integrally formed slanted, wave-shaped fins; the flat tube has opposing windward and leeward sides, and a fin base surface connecting the windward and leeward sides; the slanted, wave-shaped fins are formed on one or both sides of the fin base surface by a slanting motion, extending along the length of the flat tube and forming a periodic wave structure. The wave structure extends at an angle to the fin base surface, forming a three-dimensional curved surface, thereby creating equally spaced airflow channels between adjacent fins. This invention combines the advantages of high heat transfer coefficient, low air-side pressure drop, good drainage, and easy integrated processing, and can be widely used in heat exchange systems in air conditioning, refrigeration, automotive, and energy and chemical industries.

Description

Technical Field

[0001] This invention relates to the field of heat dissipation technology, specifically to the design of a wave-shaped shovel-fin heat exchanger with oblique shovel cuts. Background Technology

[0002] In many fields such as energy and chemical engineering, efficient heat exchange equipment is crucial for improving energy utilization efficiency and ensuring the stable operation of processes. Traditional heat exchangers, such as shell-and-tube heat exchangers, while widely used, have drawbacks such as limited heat exchange efficiency, large size, and contact thermal resistance. With the continuous development of industrial technology, higher requirements are being placed on the heat exchange performance and compactness of heat exchangers.

[0003] The shovel-fin heat exchanger, with its unique structure, can enhance fluid turbulence, thereby improving the heat transfer effect. At the same time, since the fins are directly shoveled from the pipe wall, the fins and pipe are integrally formed, eliminating contact thermal resistance and resulting in high heat transfer efficiency. However, conventional shovel-fin heat exchangers are mostly regular straight-tooth structures, and there is still room for improvement in the degree of fluid turbulence and the renewal rate of the heat exchange interface during fluid flow.

[0004] Wave-shaped structures have potential for enhancing heat transfer. They can alter the flow path of the fluid, increase the contact area and contact time between the fluid and the heat exchange surface, and promote the development of fluid turbulence. Combining a wave-shaped structure with wave-shaped fins created by oblique cutting can further optimize the fluid's flow direction and state, thereby improving heat exchange efficiency. Summary of the Invention

[0005] To address the aforementioned shortcomings of existing technologies, this invention provides a wave-shaped shovel-fin heat exchanger with oblique shovels that combines high-efficiency heat exchange with uniform airflow, thereby further improving the overall energy efficiency.

[0006] To achieve the above-mentioned technical effects, the present invention discloses a wave-shaped shovel-fin heat exchanger with oblique shovel cutting, including a flat tube and oblique wave-shaped shovel-fin integrally formed therewith; the flat tube has a windward side and a leeward side, and a fin base surface connecting the windward side and the leeward side; the oblique wave-shaped shovel-fin is formed on the fin base surface on one or both sides by shoveling, and extends along the length direction of the flat tube to form a periodic wave structure. The wave structure extends along a direction with an oblique angle to the fin base surface to form a three-dimensional spatial curved surface, thereby forming an equally spaced airflow channel between adjacent fins.

[0007] Furthermore, both the windward and leeward sides are composed of an arc segment with a radius of curvature R and a planar segment tangent to the arc segment, with the planar segment being coplanar with the base surface of the fin on the same side.

[0008] Furthermore, the wavy profile of the oblique wave-shaped shovel-shaped fin lies within a reference plane defined by the fin's base surface. Within this plane, the intersection of the windward side and the fin's base surface is defined as the Y-axis, and the intersection of the flat tube's longitudinal section and the fin's base surface is defined as the X-axis. The wavy profile of the oblique wave-shaped fin is defined by the following functional relationship:

[0009] (1);

[0010] Where FL(x) represents the equation of the wavy fin curve; A represents the amplitude of the wavy fin curve; λ is the wavelength of the wavy fin curve; and P represents the phase of the wavy fin curve.

[0011] Furthermore, the geometry of the oblique wave-shaped shovel-shaped fin is determined as follows: First, a wave-shaped reference curve is defined on the fin base surface; then, the curve is scanned and extended along a predetermined fin profile in a plane at an angle α with the fin base surface, thereby forming a wave-shaped shovel-shaped fin structure with spatial tilting characteristics.

[0012] Furthermore, the three-dimensional spatial morphology of the oblique wave-shaped shovel-shaped fin is defined by a predetermined fin profile, which lies within a fin profile reference plane. This reference plane intersects the fin base plane at an angle θ, and the reference plane is parallel to the intersection line of the windward side and the fin base plane. The spatial trajectory of the fin profile within this reference plane is described by the following set of parametric equations:

[0013] (2);

[0014] (3);

[0015] The coordinate system is defined as follows: the X-axis is the intersection of the top surface of the fin and the extended surface of the longitudinal section of the flat tube, with the positive direction pointing from the windward side to the leeward side; the Y-axis is the intersection of the upward extended surface of the windward side and the top surface of the fin, with the intersection of the two axes being the origin; the Z-axis is the direction perpendicular to the base surface of the fin, with the positive direction pointing from the top surface of the fin to the base surface of the fin; h represents the height of the wavy fin curve; a and b are the shape parameters of the fin profile, and t is in the range of [0, h].

[0016] Furthermore, the length dimension of the fin is the same as the width dimension of the fin base surface, both being L, and L is the length of n complete wave cycles of the fin. The value of L satisfies the following relationship:

[0017] (4).

[0018] Furthermore, the thickness Ft of the oblique wave-shaped shovel-shaped fin is 0.1 mm to 1 mm.

[0019] Furthermore, the oblique wave-shaped shovel-shaped fins are symmetrically distributed on the fin base surfaces on both the upper and lower sides of the flat tube, with the center surface of the flat tube being the symmetrical surface.

[0020] Furthermore, the flat tube and the oblique wave-shaped shovel-shaped fins set on it are integrally formed.

[0021] Furthermore, in refrigeration or condensation conditions, the trough structure of the oblique wave-shaped shovel-shaped fins is used to guide the condensate to slide down and be discharged along the fin's inclined direction.

[0022] The advantages and beneficial effects of this application are as follows:

[0023] The obliquely shoveled wave-fin heat exchanger provided by this invention has the following significant technical effects:

[0024] Firstly, in terms of structural performance, this invention employs a one-piece molding and shaving process, eliminating contact thermal resistance between the oblique wave-shaped shaving fins and the flat tube. This not only significantly improves heat transfer efficiency but also enhances the overall mechanical strength and reliability of the structure. While maintaining a relatively constant material usage and total heat exchange area, this design effectively increases the effective heat exchange area and improves space utilization efficiency by introducing a spatial wave-shaped curved surface formed by oblique shaving.

[0025] Secondly, in terms of fluid and heat transfer performance, the synergistic effect of the oblique wave-shaped structure significantly enhances the heat transfer process: the wave-shaped profile causes periodic changes in the flow channel cross-section, stripping and disrupting the thermal boundary layer at the crests and inducing secondary eddies at the troughs, greatly enhancing fluid turbulence; simultaneously, the oblique layout can actively guide airflow according to the fluid flow direction, optimizing the flow field distribution, achieving a synergistic effect of enhanced heat transfer and reduced flow resistance. Experimental data show that, under typical operating conditions, compared with conventional wave-shaped shovel-fin structures, this invention improves the heat transfer j-factor by 6.19% to 7.32% and reduces the drag f-factor by 3.94% to 4.65% in the Reynolds number range of 1452 to 3000, demonstrating a significant improvement in overall performance.

[0026] Furthermore, this design exhibits excellent engineering adaptability. Under humid conditions such as refrigeration or condensation, the troughs of the wave structure can form natural flow paths. Combined with the oblique arrangement of the fins, this effectively promotes the rapid removal of condensate, preventing performance degradation caused by liquid accumulation, increased resistance, or frost formation. This enhances the heat exchanger's operational stability and energy efficiency under complex conditions.

[0027] In summary, this invention achieves a comprehensive improvement in heat exchange performance, flow performance, and environmental adaptability through synergistic innovation in structure, process, and flow field. It has the advantages of compact structure, high efficiency and energy saving, reliability and durability, and is suitable for various heat exchange applications with high requirements for energy efficiency and space. Attached Figure Description

[0028] Figure 1 It is a wave-shaped shovel-fin heat exchanger with a sloping, shovel-like design.

[0029] Figure 2 A side view of a wave-shaped shovel-fin heat exchanger with oblique shovel-shaped cuts.

[0030] Figure 3 A partially enlarged schematic diagram of a wave-shaped shovel-shaped fin with oblique shovel cutting;

[0031] Figure 4 A comparison diagram of the heat exchange performance of wave-shaped shovel-shaped fins with oblique shovels cut in the opposite flow direction and ordinary shovel-shaped fins. Detailed Implementation

[0032] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are merely preferred embodiments, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this invention.

[0033] As attached Figure 1 To be continued Figure 3 As shown, this embodiment of the invention provides a wave-shaped shovel-fin heat exchanger with oblique shavings. The heat exchanger includes a flat tube 1 and obliquely wave-shaped shovel-fins 2 integrally formed thereon. The flat tube 1 has an arc-shaped windward side 3 and a leeward side 4 arranged opposite to each other, connected as a single unit by symmetrically arranged fin base surfaces 5. Specifically, both the windward side 3 and the leeward side 4 are composed of a semi-circular arc segment with a radius of curvature R and a planar segment tangent to this segment. The planar segment and the corresponding fin base surface 5 are located in the same plane. The obliquely wave-shaped shovel-fins 2 are directly formed on the fin base surface 5 using a shovel-cutting process, and are arranged at equal intervals along the length of the flat tube 1, thereby forming a series of uniform airflow channels between adjacent fins. Because the fins 2 and the flat tube 1 are integrally formed, contact thermal resistance is eliminated, significantly improving heat transfer efficiency and structural reliability.

[0034] In some specific embodiments, the oblique wave-shaped shovel-shaped fins 2 are symmetrically distributed on the upper and lower sides of the flat tube, with the center plane of the flat tube as the plane of symmetry, or are distributed on only one side.

[0035] In some specific embodiments, the windward side 3 and the leeward side 4 of the flat tube 1 can be changed, and its extension surface can be reduced as the radius of the arc surface increases, until the arc surface is tangent to the fin base surface 5.

[0036] In some specific embodiments, the oblique wave-shaped shovel-fin 2 is formed by obliquely shoveling the material of the flat tube 1. Its arrangement direction is parallel to the axis of the flat tube 1 and it is equidistantly distributed along the length of the flat tube. This equidistant design not only facilitates the consistency of the manufacturing process, but also ensures that the airflow is evenly distributed in the flow channel, further optimizing the heat exchange and flow performance.

[0037] In some specific embodiments, the geometry of the oblique wave-shaped shovel-shaped fin 2 is determined by the following method: first, a wave-shaped reference curve is defined on the fin base surface 5; then, the curve is scanned and extended along a predetermined fin profile in a plane that forms an angle α with the fin base surface 5, thereby forming a wave-shaped shovel-shaped fin structure with spatial tilting characteristics.

[0038] Specifically, the wavy reference curve is described within a reference plane defined by the fin base surface 5. Within this plane, the intersection of the windward surface 3 and the fin base surface 5 is defined as the Y-axis, and the intersection of the longitudinal section of the flat tube 1 and the fin base surface 5 is defined as the X-axis. The equation for the wavy fin curve is as follows:

[0039] (1);

[0040] in, (x) represents the equation of the wavy fin curve; A represents the amplitude of the wavy fin curve, λ is the wavelength of the wavy fin curve, and P represents the phase of the wavy fin curve; in a preferred embodiment, A = 0.3 mm. =1, P=0.

[0041] The aforementioned wave-shaped structure offers several technical benefits: First, the periodically changing crests and troughs cause the flow channel cross-section to contract and expand regularly. At the crests, the thermal boundary layer is effectively stripped and disrupted, while at the troughs, controllable vortex flow is induced, significantly enhancing fluid turbulence and convective heat transfer. Second, compared to straight fins of the same projected size, the wave-shaped structure provides a larger effective heat transfer surface area within a limited space, improving space utilization and heat transfer capacity. Furthermore, the wave profile helps guide airflow evenly across the flow channel cross-section, reducing flow separation and localized high-speed zones. This enhances heat transfer while achieving lower flow resistance, helping to reduce the energy consumption of the supporting fan and improve the overall system energy efficiency.

[0042] Furthermore, the three-dimensional spatial shape of the oblique wave-shaped shovel-shaped fin 2 is defined by a predetermined fin profile, which lies within a fin profile reference plane. This reference plane intersects with the fin base surface 5 at an angle θ, and the reference plane is parallel to the intersection line of the windward surface 3 and the fin base surface 5. The spatial trajectory of the fin profile within this reference plane is described by the following set of parametric equations:

[0043] (2);

[0044] (3);

[0045] The coordinate system is defined as follows: the X-axis is the intersection of the top surface 6 of the fin and the extended surface of the longitudinal section of the flat tube, with the positive direction pointing from the windward side 3 to the leeward side 4; the Y-axis is the intersection of the upward extended surface of the windward side 3 and the top surface 6 of the fin, with the intersection of the two axes being the origin; the Z-axis is the direction perpendicular to the base surface 5 of the fin, with the positive direction pointing from the top surface 6 of the fin to the base surface 5 of the fin; h represents the height of the wavy fin curve; a and b are the shape parameters of the fin profile, and t ranges from [0, h]. In a preferred embodiment, the parameters are a = 0.002, b = 0.0917, and h = 5.353 mm.

[0046] The oblique shaving forming method employed in this invention, while maintaining a relatively constant amount of raw materials and total heat exchange area, significantly enhances the turbulence of the air-side fluid and the renewal frequency of the heat exchange interface through the coordinated design of the fin spatial orientation and cross-sectional shape. This achieves a substantial improvement in heat exchange performance without significantly increasing manufacturing costs. Furthermore, addressing the issue of condensation on the fin surface during refrigeration or condensation operations, the wave-shaped structure of this invention provides effective drainage: the trough structure acts as a temporary storage and guiding channel for condensate. Combined with the fin profile and tilt direction, this allows condensate to be quickly guided downwards, reducing liquid film retention and accumulation. This characteristic not only helps maintain low air resistance but also prevents a severe decrease in heat exchange efficiency due to water accumulation and frost formation, improving the heat exchanger's operational stability and energy efficiency under wet conditions.

[0047] The thickness F of the oblique wave-shaped shovel-shaped fin 2 t The thickness is between 0.1 mm and 1 mm, and in the preferred embodiment, it is set to 0.3 mm. This thickness balances structural rigidity, manufacturing feasibility, and heat transfer efficiency. Meanwhile, the length dimension of fin 2 and the width dimension of fin base surface 5 are the same and both are L, where L is the length of n complete wave cycles of the fin. The value of L satisfies the following relationship:

[0048] (4);

[0049] This constraint ensures that the fins contain n complete wave cycles along their length, which is beneficial for the full development of the periodicity of flow and heat transfer. In a preferred embodiment, n = 4.

[0050] Application examples

[0051] To verify the technical effects of this invention, unit performance tests were conducted on the inclined, shovel-fin heat exchanger of this invention. The test conditions were set as follows: the water side wall temperature was maintained at a constant 50°C, the air inlet temperature was 25°C, and the air inlet velocity was calculated and determined based on the fluid continuity equation and the Reynolds number (Re) definition. For comparison, a conventional shovel-fin heat exchanger (non-inclined design) with the same external dimensions and total heat exchange area was selected for parallel testing to objectively evaluate the performance improvement brought about by the structure of this invention.

[0052] Figure 4 The thermodynamic performance comparison of the two fin structures is presented under specific flow directions. Tests were conducted at three characteristic Reynolds numbers (Re=1452, 2312, 3000), and the j-factor characterizing heat transfer performance and the f-factor characterizing flow resistance were obtained. Specific experimental data are shown in Table 1 below:

[0053] Table 1

[0054]

[0055] Data results show that, under the action of the obliquely shoveled wave fin structure described in this invention, within the tested Re number range, its heat transfer performance (j-factor) is significantly improved by 6.19% to 7.32% compared to the comparative example, while the flow resistance (f-factor) is simultaneously reduced by 3.94% to 4.65%. This fully demonstrates that, by introducing the geometric feature of oblique shovels, this invention not only effectively enhances fluid disturbance and heat transfer but also optimizes the flow structure within the flow channel, thereby improving overall heat transfer performance while reducing flow resistance, demonstrating an excellent synergistic effect of efficiency enhancement and drag reduction. These results verify that the oblique design has a positive effect on guiding airflow, disrupting the boundary layer, and regulating the flow field distribution, significantly outperforming conventional wave fin structures without oblique design.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A wave fin heat exchanger of oblique cutting and shaving, characterized in that, It includes a flat tube (1) and an integrally formed oblique wave-shaped shovel-shaped fin (2); the flat tube (1) has a windward side (3) and a leeward side (4) with opposite sides, and a fin base surface (5) connecting the windward side (3) and the leeward side (4); the oblique wave-shaped shovel-shaped fin (2) is formed on the fin base surface (5) on one or both sides by shoveling, and it extends along the length direction of the flat tube (1) to form a periodic wave structure. The wave structure extends along a direction with an inclined angle to the fin base surface (5) to form a three-dimensional spatial curved surface, thereby forming an equally spaced airflow channel between adjacent fins.

2. The wave fin exchanger with oblique cut wave fins according to claim 1, characterized in that Both the windward side (3) and the leeward side (4) are composed of an arc segment with a radius of curvature R and a planar segment tangent to the arc segment. The planar segment is coplanar with the fin base surface (5) on the same side.

3. The wave fin exchanger with oblique cut wave fins according to claim 1, characterized in that, The wavy profile of the oblique wave-shaped shovel-shaped fin (2) lies in a reference plane defined by the fin base surface (5). In this plane, the intersection of the windward side (3) and the fin base surface (5) is defined as the Y-axis, and the intersection of the longitudinal section of the flat tube (1) and the fin base surface (5) is defined as the X-axis. The wavy profile of the oblique wave-shaped fin is defined by the following functional relationship: （1）； wherein (x) represents an equation of a slanted wavy fin curve; A represents an amplitude of the wavy fin curve, λ is a wavelength of the wavy fin curve, and P represents a phase of the wavy fin curve.

4. The wave fin exchanger of claim 3, wherein, The geometry of the oblique wave-shaped shovel fin (2) is determined by the following method: first, a wave-shaped reference curve is defined on the fin base surface (5); then, the curve is scanned and extended along a predetermined fin profile in a plane that forms an angle α with the fin base surface (5), thereby forming a wave shovel fin structure with spatial tilting characteristics.

5. The wave fin exchanger of claim 4, wherein, The three-dimensional spatial shape of the oblique wave-shaped shovel-shaped fin (2) is defined by a predetermined fin profile, which is located in a fin profile reference plane. This reference plane intersects with the fin base plane (5) at an angle of θ, and the reference plane is parallel to the intersection line of the windward surface (3) and the fin base plane (5). The spatial trajectory of the fin profile in this reference plane is described by the following set of parametric equations: （2）； （3）； The coordinate system is defined as follows: the X-axis is the line of intersection between the top surface of the fin (6) and the extended surface of the longitudinal section of the flat tube, with the positive direction being from the windward side (3) to the leeward side (4); the Y-axis is the line of intersection between the upward extended surface of the windward side (3) and the top surface of the fin (6), with the intersection of the two axes being the origin of the coordinate system; the Z-axis is the direction perpendicular to the base surface of the fin (5), with the positive direction being from the top surface of the fin (6) to the base surface of the fin (5); h represents the height of the wavy fin curve; a and b are the shape parameters of the fin profile, and t is in the range of [0, h].

6. The wave fin exchanger of claim 3, wherein, The length dimension of fin 2 is the same as the width dimension of fin base surface 5, both being L, and L is the length of n complete wave cycles of the fin. The value of L satisfies the following relationship: （4）。 7. The wave fin exchanger of claim 1, wherein, The thickness F of the oblique wave-shaped finned fin (2) is 0.1 mm to 1 mm. t is 0.1 mm to 1 mm.

8. The obliquely shoveled wave-fin heat exchanger according to claim 1, characterized in that, The oblique wave-shaped shovel-shaped fins (2) are symmetrically distributed on the base surface (5) of the fins on the upper and lower sides of the flat tube (1), and the center surface of the flat tube is the symmetrical surface.

9. The obliquely shoveled wave-fin heat exchanger according to claim 1, characterized in that: The flat tube (1) and the oblique wave-shaped shovel-shaped fins (2) disposed thereon are integrally formed.

10. The obliquely shoveled wave-fin heat exchanger according to claim 1, characterized in that, In refrigeration or condensation conditions, the trough structure of the oblique wave-shaped shovel-shaped fin (2) is used to guide the condensate to slide down and be discharged along the fin's inclined direction.

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