Fin structure, heat exchanger and refrigeration equipment

Abstract

The utility model discloses a fin structure, heat exchanger and refrigeration equipment, fin structure includes: fin and at least one louver of windward that is located on the fin, and the louver of windward has a plurality of obliquely arranged windward blades, the oblique angle of the windward blade in the same louver of windward gradually increases along the airflow direction, and the oblique angle of any two adjacent windward blades in the same louver of windward is different by fixed angle delta theta. The utility model discloses the louver structure of the attack angle gradual change replaces the traditional fixed attack angle design, and since the oblique angle of the blade gradually increases along the airflow direction, when the flow rate is low, the shielding effect of the upstream blade to the downstream blade is not obvious, and at the same time, the negative pressure exists behind the downstream blade, so that the flow rate between the blades is relatively fast, is favorable to heat exchange, realizes the substantial promotion of heat exchange efficiency.

Description

Technical Field

[0001] This utility model relates to the field of heat exchanger technology, and in particular to finned structures, heat exchangers, and refrigeration equipment. Background Technology

[0002] As a key heat transfer component in air conditioning systems, the performance of heat exchangers has a decisive impact on the overall energy efficiency of air conditioning. Under limited space and fixed operating conditions, the physical volume constraints of heat exchangers directly limit the heat transfer area that can be arranged in finned tubes, which has become a core bottleneck in improving heat transfer efficiency. To address this contradiction, current technological approaches mainly focus on breakthroughs in two dimensions: first, reducing the thickness of the thermal boundary layer at the gas-liquid interface through microstructure design on the fin surface; and second, enhancing turbulent disturbance of the fluid outside the tubes to improve the convective heat transfer coefficient. As the core functional carrier for enhancing heat transfer, fin structure design plays a crucial role in this process.

[0003] Existing fin systems are mainly classified into continuous types (such as flat fins and corrugated fins), discontinuous types (such as vented fins), multifunctional types (such as fins with vortex generators), and heterogeneous composite fins. Although discontinuous structures such as vented and corrugated fins can disrupt the thermal boundary layer and enhance heat transfer, the widely used louvered fins still have drawbacks due to their fixed angle of attack. The constant tilt angle of the guide vanes leads to intensified flow separation and non-uniform distribution of turbulence intensity. While generating excessive wind resistance and energy consumption, the disordered flow field organization prevents the full release of heat transfer potential.

[0004] With global energy shortages and rising energy efficiency standards, the industry is attempting breakthroughs through structural innovation (corrugated / needle / spiral configurations), intelligent manufacturing, and the application of new materials (such as graphene-based composites and nano-coating technology). However, new materials face industrialization bottlenecks such as high manufacturing costs, insufficient technological maturity, and standard compatibility. Under the existing heat exchanger architecture, achieving energy efficiency improvements still requires a return to structural optimization. Especially given the inability to overcome volume constraints, there is an urgent need to develop novel fin structures to synergistically resolve the contradiction between enhanced heat transfer and flow resistance control. Utility Model Content

[0005] To address the shortcomings of low heat exchange efficiency in existing technologies, this invention proposes a finned structure, a heat exchanger, and a refrigeration device. It employs a multi-angle continuous louver structure to improve the fluid flow field, increase the heat exchange area, and enhance heat exchange efficiency.

[0006] The technical solution adopted in this utility model is to design a fin structure, including: fins and at least one windward louver disposed on the fins, the windward louver having multiple inclined windward blades; the windward blades in the same windward louver gradually increase the inclination angle along the airflow direction.

[0007] Furthermore, the tilt angles of any two adjacent windward blades within the same windward louver differ by a fixed angle Δθ.

[0008] Furthermore, the fixed angle Δθ is 3°.

[0009] Furthermore, the number of wind-facing blades in the wind-facing louver is 5, and the tilt angles of the wind-facing blades in the same wind-facing louver are 18°, 21°, 24°, 27° and 30° respectively.

[0010] Furthermore, the fins are also provided with at least one leeward louver, which has multiple inclined leeward blades.

[0011] Furthermore, each windward louver is paired with a leeward louver to form an airflow reversal zone, and multiple airflow reversal zones are arranged at intervals between the fins.

[0012] Furthermore, the shape of the leeward louver is the same as that of the windward louver, and the opening direction of the leeward louver is opposite to that of the windward louver.

[0013] This invention also proposes a heat exchanger, comprising: a plurality of parallel fins and a plurality of heat exchange tubes passing through the fins, wherein the fins adopt the aforementioned fin structure.

[0014] This utility model also proposes a refrigeration device, including: a compressor and the aforementioned heat exchanger.

[0015] In some embodiments, the refrigeration device is an air conditioner.

[0016] Compared with the prior art, this utility model adopts a louver structure with a gradually changing angle of attack to replace the traditional fixed angle of attack design. Since the tilt angle of the blades gradually increases along the airflow direction, when the flow velocity is low, the shielding effect of the upstream blades on the downstream blades is not obvious. At the same time, there is a negative pressure behind the downstream blades, which makes the fluid flow velocity between the blades relatively fast, which is conducive to heat exchange and achieves a significant improvement in heat exchange efficiency. Attached Figure Description

[0017] The present invention will now be described in detail with reference to the embodiments and accompanying drawings, wherein:

[0018] Figure 1 A partial plan view of the fin structure of this utility model;

[0019] Figure 2 This is a partial three-dimensional schematic diagram of the fin structure of this utility model;

[0020] Figure 3 This is an overall schematic diagram of the fin structure of this utility model;

[0021] Figure 4 yes Figure 3 Schematic diagram of the cross section at point AA;

[0022] Figure 5 yes Figure 3 A partial schematic diagram at point B in the middle;

[0023] Figure 6a This is a local flow field cloud diagram of the fin structure of CF1;

[0024] Figure 6b This is a local flow field cloud diagram of the fin structure of CF2;

[0025] Figure 6c This is a local flow field cloud diagram of the fin structure of CF3;

[0026] Figure 6d This is a local flow field cloud diagram of the fin structure of CF4;

[0027] Figure 6e This is a local flow field cloud diagram of the fin structure of CF5;

[0028] Figure 7a This is a comparison chart of the j-factors of the five experimental groups;

[0029] Figure 7b This is a comparison chart of j / j0 for the angle of attack gradient experimental group;

[0030] Figure 7c This is a comparison chart of the f-factors of the five experimental groups;

[0031] Figure 7d This is a comparison chart of f / f0 for the angle of attack gradient experimental group;

[0032] Figure 7e This is a comparison chart of the overall performance of the angle of attack gradient experimental group; Attached image description:

[0034] 1. Fins; 11. Windward louvers; 111. Windward blades; 12. Leeward louvers; 121. Leeward blades; 13. Airflow reversal zone; 14. Mounting holes; 2. Heat exchange tubes. Detailed Implementation

[0035] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model 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 only used to explain this utility model and are not intended to limit this utility model.

[0036] like Figures 1 to 3As shown, the finned structure proposed in this invention is suitable for heat exchangers, especially finned tube heat exchangers. This heat exchanger includes multiple parallel-arranged fins 1 and multiple heat exchange tubes 2 penetrating each fin. The fins 1 are provided with louvers and mounting holes 14 for inserting the heat exchange tubes 2. Forced convection is generated within the equidistant flow channels formed between the fins 1, and heat exchange occurs between the surface of the fins 1 and the outer wall of the heat exchange tubes 2. Simultaneously, the refrigerant flows within the heat exchange tubes 2, transferring heat between the refrigerant and the air-side fluid through the tube wall. The finned structure of this invention, by employing louvers with a gradually changing angle of attack, effectively improves the fluid flow field within the heat exchanger, significantly enhancing heat exchange efficiency.

[0037] like Figures 2 to 4 As shown, specifically, the fin structure includes: fin 1 and at least one windward louver 12 disposed on the fin. The windward louver 12 has multiple inclined windward blades 111. The windward blades 111 in the same windward louver 12 gradually increase the inclination angle along the airflow direction. The inclination angle refers to the angle between the windward blades 111 and the fin 1, that is, the angle of attack of the blades.

[0038] For ease of understanding, within the same windward louver 12, two adjacent windward blades 111 are referred to as the upstream blade and the downstream blade, respectively. The airflow passes through the upstream blade and then the downstream blade. Since the tilt angle of the upstream blade is smaller than that of the downstream blade, when the flow velocity is low, the blocking effect of the upstream blade on the downstream blade is not obvious. At the same time, there is a negative pressure behind the downstream blade, which makes the fluid flow velocity between the blades relatively fast, which is conducive to heat exchange and achieves a significant improvement in heat exchange efficiency.

[0039] It should be understood that the slats inside the venetian blinds can be the same or different lengths. For example... Figure 1 , 2 As shown, the slats inside the venetian blinds are of uniform length, and the blinds are square in shape; as Figures 3 to 5 As shown, the slats inside the venetian blinds have a gradually changing length, and the blinds themselves are arc-shaped. In practical applications, the slat length is designed according to specific usage requirements; this invention does not impose any special limitations on this.

[0040] like Figure 4As shown, in a preferred embodiment of this invention, the tilt angles of any two adjacent windward blades 111 within the same windward louver 111 differ by a fixed angle Δθ. By designing the tilt angles of the windward blades 111 to increase in a gradient, flow field optimization is achieved. The fin structure of the louver with continuously varying angles of attack can effectively improve the flow field. In the initial stage of the incoming flow, a smaller angle of attack reduces flow resistance, weakens the shielding effect of the upstream blades on the fluid, and ensures the utilization rate of the basic heat transfer area. As the velocity gradient develops, the progressively increasing angle of attack continuously induces secondary flow, forming a local negative pressure zone on the back side of the blades using the Bernoulli effect, accelerating the mass and momentum exchange between the main fluid and the boundary layer. The gradient angle of attack layout also promotes the development of directional vortices, enabling the fluid to form an orderly acceleration-mixing-re-acceleration cycle in the airflow channel between the blades, significantly improving the turbulence intensity.

[0041] As a further optimization, the fixed angle Δθ is set to 3°, which effectively ensures that the airflow forms a smooth transition streamline along the blade surface. Moreover, this gradient value can be adapted to the characteristics of conventional stamping processes, achieving high-precision fin mass production within the material forming limit, while taking into account both structural integrity and manufacturing economy.

[0042] Through in-depth research, the inventors discovered that, since the number of louver blades needs to be determined according to the mold, and based on a comprehensive balance between mold forming process constraints and thermodynamic performance verification, this design adopts a five-stage gradient angle-of-attack louver structure. This parameter setting stems from a dual evaluation: if the number of louver stages is too small, the effective range of a single-stage structure is limited, making it difficult to fully activate the synergistic enhancement effect of the gradient flow field, resulting in heat transfer efficiency failing to approach the theoretical optimization threshold; conversely, when the number of stages is too large, limitations imposed by the fin material thickness and stamping forming limits will trigger multiple process risks—overload of mold precision leading to structural integrity deterioration, increased stress concentration at the blade roots, and microscale feature distortion causing the actual flow field to deviate from the design target. The five-stage design strikes a critical balance: it satisfies the mold manufacturability window (ensuring accurate forming of the minimum feature size) while fully releasing the heat transfer enhancement potential, achieving the optimal solution for overall performance while maintaining structural reliability.

[0043] Based on this, the preferred solution is to design the tilt angles of the windward blades within the same windward louver to be 18°, 21°, 24°, 27°, and 30°, respectively. This preferred solution can achieve lower flow resistance and higher overall heat exchange performance. The verification data will be explained in detail below.

[0044] like Figures 1 to 5 As shown, generally speaking, the fin 1 is also provided with at least one leeward louver 12. The leeward louver 12 has a plurality of inclined leeward blades 121. The leeward blades 121 use steep blade angles to force airflow separation and generate high-intensity vortices to enhance fluid mixing.

[0045] As a further optimization, each windward louver 11 is paired with a leeward louver 12 to form an airflow reversal zone 13. The pairing of the windward and leeward louvers 11 and 12 enables complementary tilt angles, and the flow field efficiently relays between the windward and leeward louvers to maintain turbulence intensity and avoid flow energy attenuation. Multiple airflow reversal zones 13 are arranged at intervals on the fins 1, each airflow reversal zone 13 forming a micro-energy conversion unit to match the flow velocity and heat exchange requirements at its location.

[0046] like Figure 4 As shown, in a preferred embodiment of this utility model, the shape of the leeward louver 12 is the same as that of the windward louver 11, and the opening direction of the leeward louver 12 is opposite to that of the windward louver 11. That is, the leeward blades 121 within the same leeward louver 12 gradually decrease their tilt angle along the airflow direction. The leeward blades 121 and the windward blades 111 correspond one-to-one, and the decrease in the tilt angle of the leeward blades 121 is consistent with the increase in the tilt angle of the windward blades 111. The advantage of this design is that during installation, there is no need to distinguish between the positive and negative directions. By simply changing the installation direction of the fins 1, the functions of the windward louver 11 and the leeward louver 12 can be interchanged, making installation convenient and simplifying the manufacturing process.

[0047] It should be understood that the windward louvers 11 and leeward louvers 12 mentioned in this article are defined by the relationship between the louvers and the airflow direction. The louvers with the opening direction facing the airflow direction are called windward louvers 11, and the louvers with the opening direction away from the airflow direction are called leeward louvers 12.

[0048] The verification results of the preferred solution proposed in this utility model are as follows:

[0049] experimental group Δθ Blade tilt angle (windward louvers + leeward louvers) CF1 +2° (22°,24°,26°,28°,30°,28°,26°,24°,22°) CF2 +3° (18°,21°,24°,27°,30°,27°,24°,21°,18°) CF3 0° (30°,30°,30°,30°,30°,30°,30°,30°,30°) CF4 -3° (30°,27°,24°,21°,18°,21°,24°,27°,30°) CF5 -2° (30°,28°,26°,24°,22°,24°,26°,28°,30°)

[0050] The table above contains five experimental groups: CF3 is the traditional scheme, CF2 is the preferred scheme of this utility model, and CF1, CF4 and CF5 are control groups. Figures 6a to 6e The diagram shows local flow field contour plots of the louvers for five experimental groups. Figures 7a to 7e The performance parameters of the five experimental groups are compared.

[0051] Where Re is the Reynolds number, which represents the state of fluid flow (laminar or turbulent) and reflects the relative importance of inertial forces and viscous forces;

[0052] j is the heat transfer factor, which represents a parameter related to flow heat transfer or two-phase flow heat transfer and is used to characterize the actual heat transfer intensity.

[0053] j / j0 represents the relative rate of change of heat transfer performance, reflecting the impact of structural optimization on heat transfer; j0 represents the heat transfer factor of the reference fin. When (j / j0) > 1, heat transfer is enhanced; when (j / j0) < 1, heat transfer is weakened.

[0054] f is the drag factor, used to quantify flow resistance;

[0055] f / f0 represents the relative rate of change of flow resistance, characterizing the influence of structure on flow resistance. f0 represents the drag factor of the reference fin; when (f / f0) > 1, the drag increases; when (f / f0) < 1, the drag decreases.

[0056] (j / j0) / (f / f0) is used to evaluate the balance between heat transfer gain and flow resistance cost, characterizing the improvement in heat transfer capacity that can be obtained per unit pump power; when ((j / j0) / (f / f0))>1, a net heat transfer gain is obtained on the basis of flow resistance improvement; when ((j / j0) / (f / f0))<1, the flow resistance cost exceeds the heat transfer gain.

[0057] Based on the above data, the following conclusions can be drawn:

[0058] The fin structure employing continuously tapered louvers with varying angles of attack sacrifices some heat transfer performance, but its structure improves the fluid flow field between the fins and reduces fluid flow resistance. This resistance is particularly pronounced at lower Reynolds numbers.

[0059] When Re = 408, the j-factors of CF1, CF2, CF4, and CF5 decreased by 3.18%, 4%, 5.65%, and 3.68% compared to CF3, respectively, but their f-factors decreased by 7.44%, 11.91%, 13.06%, and 8.08%, respectively. When Re = 1223, the j-factors of CF1, CF2, CF4, and CF5 decreased by 0.76%, 0.63%, 2.16%, and 1.42% compared to CF3, respectively, but their f-factors decreased by 4.85%, 7.64%, 9.61%, and 6.05%, respectively. This indicates that under the same pressure drop, the fin structure of the continuously tapered louvered louver with a continuously tapered angle of attack has better overall heat transfer performance.

[0060] In addition, (j / j0) / (f / f0) was introduced to measure the overall performance of four louvered fin structures with continuously varying angles of attack: CF1, CF2, CF4, and CF5. The results show that CF2(+3°) has the best overall performance within the simulation range, and its overall performance is even better at low Reynolds numbers.

[0061] The experiment used an air conditioner with a rated cooling capacity of 3.5KW for rated cooling capacity testing. The outdoor unit was equipped with different multi-angle-of-attack fin structures, and the test structures are as follows:

[0062] experimental group Test conditions Monitoring frequency (Hz) Ability (W) Power (W) Energy efficiency <![CDATA[Air volume (m 3 / h)]]> CF1 Rated refrigeration 52 3412.8 787.4 4.334 828.1 CF2 Rated refrigeration 52 3475.7 786.8 4.418 842 CF3 Rated refrigeration 52 3387 790 4.29 881.3 CF4 Rated refrigeration 52 3459.4 788.9 4.385 871.6 CF5 Rated refrigeration 52 3392 789 4.3 870

[0063] Based on the performance test results, the overall performance index for heat exchange is as follows: CF2 (cooling capacity: 3475.7W) > CF4 (cooling capacity: 3459.4W) > CF1 (cooling capacity: 3412.8W) > CF5 (cooling capacity: 3392W) > CF3 (cooling capacity: 3387W). It is evident that CF2 has a higher cooling capacity in the rated cooling capacity test.

[0064] like Figure 3 As shown, this utility model also proposes a heat exchanger, including: a plurality of parallel fins 1 and a plurality of heat exchange tubes 2 passing through the fins 1. The fins adopt the above-mentioned fin structure, which effectively improves the overall heat exchange efficiency of the heat exchanger.

[0065] The aforementioned heat exchanger can be applied in refrigeration equipment, including but not limited to air conditioners. For ease of understanding, taking an air conditioner as an example, a household air conditioner includes a compressor, an indoor heat exchanger, and an outdoor heat exchanger. The indoor and / or outdoor heat exchanger adopts the fin structure of the gradually increasing angle-of-attack louver proposed in this invention. Because the tilt angle of the blades gradually increases along the airflow direction, when the flow velocity is low, the blocking effect of the upstream blades on the downstream blades is not significant. Simultaneously, there is a negative pressure behind the downstream blades, resulting in a relatively fast fluid flow velocity between the blades. This is beneficial for optimizing the heat exchange effect, achieving a significant improvement in heat exchange efficiency, and increasing the air conditioner's energy efficiency ratio.

[0066] It should be noted that the terminology used above is for describing specific embodiments only and is not intended to limit the exemplary embodiments according to this utility model. When the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. The order of execution of actions, steps, etc., in the apparatus and methods shown in the specification and drawings can be implemented in any order unless a specific express order is specified, and as long as the output of the preceding process is not used in the subsequent process. Similar sequential terms used for ease of description do not imply that such an order must be followed.

[0067] Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0068] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. Finned structure, including: The fins and at least one windward louver disposed on the fins, the windward louver having a plurality of inclined windward blades; characterized in that the windward blades within the same windward louver gradually increase in inclination angle along the airflow direction.

2. The fin structure according to claim 1, characterized in that, The tilt angles of any two adjacent windward blades within the same windward louver differ by a fixed angle Δθ.

3. The fin structure according to claim 2, characterized in that, The fixed angle Δθ is 3°.

4. The fin structure according to claim 1, characterized in that, The number of wind-facing blades in the wind-facing louver is 5, and the tilt angles of the wind-facing blades in the same wind-facing louver are 18°, 21°, 24°, 27° and 30° respectively.

5. The fin structure according to any one of claims 1 to 4, characterized in that, The fin is also provided with at least one leeward louver, which has multiple inclined leeward blades.

6. The fin structure according to claim 5, characterized in that, Each of the windward louvers is paired with a leeward louver to form an airflow reversal zone, and the fins are arranged with multiple airflow reversal zones at intervals.

7. The fin structure according to claim 5, characterized in that, The shape of the leeward louver is the same as that of the windward louver, and the opening direction of the leeward louver is opposite to that of the windward louver.

8. Heat exchanger, including: A plurality of parallel fins and a plurality of heat exchange tubes passing through the fins, characterized in that the fins adopt the fin structure according to any one of claims 1 to 7.

9. A refrigeration device, characterized in that, include: The compressor and the heat exchanger as described in claim 8.

10. The refrigeration equipment according to claim 9, characterized in that, The refrigeration equipment is an air conditioner.

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