Axial-flow fan blade and air outlet device

Abstract

The utility model provides an axial-flow fan blade and an air outlet device, the axial-flow fan blade comprises a hub and a plurality of blades, the suction surface of each blade is provided with an airflow disturbance area, a first smooth area and a second smooth area, and the first smooth area is separated from the airflow disturbance area through a first arc line; the first smooth area and the airflow disturbance area are separated through a first arc line, the second smooth area and the airflow disturbance area are separated through a second arc line, the first arc line, the second arc line and the outer edge share the same circle center, the radius of the outer edge is R, the radius of the first arc line is larger than or equal to 0.4 R, and the radius of the second arc line is smaller than or equal to 0.8 R; the blade further comprises a protruding structure, the protruding structure is located in the airflow disturbance area and covers the airflow disturbance area, the protruding structure comprises a plurality of protrusions, and the protrusions protrude outwards from the suction face. According to the axial flow fan blade, under the condition that the original appearance of the fan blade is not changed, the protrusions are additionally arranged on the fan blade to change the area with the large turbulence energy, then the rotation noise of the fan blade is changed, and meanwhile the input power of a driving motor is effectively improved under the condition that the air volume is guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of fan technology, specifically to an axial flow fan blade and an air outlet device. Background Technology

[0002] Axial flow fans are widely used due to their simple structure, ease of installation, and large air volume. Currently, air conditioners used in homes, office buildings, and large shopping malls employ axial flow fans in their outdoor units to rapidly exchange heat in the heat exchanger. However, as consumer demands for product quality increase, axial flow impellers have been found to have noise and airflow issues. When the airflow from the axial flow fan is low, the heat exchange performance of the outdoor unit's heat exchanger deteriorates, leading to a decrease in overall air conditioner performance. Therefore, the airflow and noise levels of the axial flow fans in an air conditioner have a significant impact on its overall performance.

[0003] An axial flow fan blade with a concave structure has been developed. The blade has a recess that curves from the pressure surface to the suction surface. By constraining the area of ​​the recess, the location of the lowest point of the cross-section, and the degree of concavity, the axial flow fan blade can achieve greater work capacity without changing its rotational speed and overall dimensions, thereby reducing fan operating noise and improving sound quality. However, the pressure surface of the fan blade typically has a relatively low airflow velocity, high pressure, and relatively stable airflow, making it less susceptible to the influence of microstructures. Therefore, in practice, the effect of adding a recess to the pressure surface of the blade to improve noise is not significant.

[0004] There is also an axial flow impeller and axial flow fans and air conditioners incorporating this impeller. The axial flow impeller has a concave notch in the middle region of its trailing edge, and convex arc-shaped portions at both ends of the concave notch. The combination of the concave notch and the convex arc-shaped portions alters the pressure distribution of the blades, reducing boundary layer separation and thus reducing eddies generated at the trailing edge, thereby lowering noise. At the same rotational speed, the airflow remains essentially constant, reducing the noise and weight of the axial flow impeller and lowering the drive power of the motor. However, this structure requires significant modifications to the impeller structure, which affects the airflow and consequently the heat exchanger's heat exchange efficiency. Utility Model Content

[0005] The primary objective of this invention is to provide an axial flow fan blade that, without altering the original shape of the blade, changes the area with higher turbulent kinetic energy by adding protrusions to the blade, thereby reducing the rotational noise of the blade. Simultaneously, it effectively improves the input power of the drive motor while maintaining airflow.

[0006] The second objective of this invention is to provide an air outlet device having the aforementioned axial flow fan blades.

[0007] To achieve the aforementioned first objective, this utility model provides an axial flow fan blade, including a hub and multiple blades. Each blade is arranged circumferentially along the hub. Each blade includes a leading edge, an outer edge, a trailing edge, and an inner edge arranged sequentially along its circumference. The inner edge is connected to the hub. The two sides of the blade are a suction surface and a pressure surface, respectively. The suction surface has an airflow disturbance region, a first smooth region, and a second smooth region. Along the radial direction of the blade, from the inner edge to the outer edge, the first smooth region, the airflow disturbance region, and the second smooth region are arranged sequentially. The first smooth region is separated from the airflow disturbance region by a first arc-shaped line, and the second smooth region is separated from the airflow disturbance region by a second arc-shaped line. The first arc-shaped line, the second arc-shaped line, and the outer edge share a common center. The radius of the outer edge is R. The radius of the first arc-shaped line is greater than or equal to 0.4R, and the radius of the second arc-shaped line is less than or equal to 0.8R. The blade also includes a protruding structure located in and covering the airflow disturbance region. The protruding structure includes multiple protrusions that protrude outward from the suction surface.

[0008] As can be seen from the above scheme, when the axial flow fan is in operation, under the action of centrifugal force, some airflow will flow towards the outer edge of the blade along the radial direction. The airflow along the radial direction of the blade will inevitably interfere with the airflow flowing along the axial direction, thus generating greater disturbance in the airflow disturbance area of ​​the blade's suction surface. This increases the motor power, reduces the effective work done by the blade, and also reduces the airflow. Due to the interference of radial airflow, aerodynamic noise will also be generated on the blade surface, affecting the user's comfort.

[0009] This utility model's axial flow fan blade optimizes the blade's shape and structure. Without altering the original blade shape, it incorporates raised structures in areas of high turbulent kinetic energy to modify these areas, thereby reducing rotational noise. Simultaneously, it effectively improves the input power of the drive motor while maintaining airflow. Furthermore, the added raised structures increase the blade's strength and rigidity, reducing mechanical vibration and further lowering noise.

[0010] Furthermore, the airflow velocity is higher and the pressure is lower on the suction side. Adding a raised structure to the suction side can more effectively influence the airflow characteristics, reduce separation, and improve airflow adhesion, thereby increasing efficiency. On the pressure side of the fan blade, the airflow velocity is relatively lower and the pressure is higher, resulting in a more stable airflow that is less susceptible to the influence of microstructures. The effect of a raised structure on the pressure side is not significant on the suction side. Therefore, the axial flow fan blade of this invention uses a raised structure on the suction side to alter the airflow characteristics, achieving a more significant effect.

[0011] Meanwhile, if the entire suction surface of the blade is covered with raised structures, it will not only increase the complexity of the manufacturing process and thus increase manufacturing costs, but also make the surface cleaning more difficult, especially in humid or dusty environments, where dirt can easily accumulate on the raised structures, affecting the performance of the blades. Excessive raised structures can also lead to uneven airflow distribution and increased local airflow disturbance, potentially causing more eddies and separation, thus reducing the overall efficiency of the blades. This invention addresses this by arranging raised structures in areas of significant airflow disturbance—areas with greater turbulence and a greater impact on the blades. Compared to covering the entire surface with raised structures, this effectively reduces the number of processes required while achieving the same effect as covering the entire surface with raised structures, thus saving costs.

[0012] A preferred embodiment is that the radius of the first arc is greater than or equal to 0.45R; and / or the radius of the second arc is less than or equal to 0.75R.

[0013] A preferred embodiment is that the protrusions on at least one blade are arranged in an array, and the rows of protrusions on the same blade are arranged along an arc line, with each arc line sharing the same center with the first arc line.

[0014] A further option is that the interval L between two adjacent rows of protrusions is in the range of 0.002R to 0.02R; and / or the interval M between two adjacent columns of protrusions is in the range of 0.01R to 0.02R.

[0015] It is evident that the size and arrangement of the protrusions are important parameters affecting the flow field. This invention restricts the relevant parameters and arrangement of the protrusions, enabling the fan blades to operate at their highest efficiency while simultaneously reducing drag.

[0016] A further proposed approach is to set the ratio of L to M within the range of 0.1 to 0.8.

[0017] Therefore, changing the ratio of L to M can alter the arrangement of the protrusions on the suction surface of the fan blades, thereby changing the flow field characteristics. When the outdoor unit's fan blade speed is high, the centrifugal force formula F = mω 2As can be seen from the graph, when the fan blade rotates at a higher speed, the centrifugal force is greater, resulting in greater radial disturbance and axial disturbance of the blade. This reduces the useful work done by the blade and consequently affects the output airflow. By changing the ratio of L to M to between 0.1 and 0.5, the radial arrangement of the protrusions becomes denser. The protrusions indirectly form an uneven surface, which weakens the radial airflow disturbance as it passes over the protrusions on the blade surface, thus achieving drag reduction and noise reduction. Furthermore, when the fan blade rotates at a lower speed, the centrifugal force generated by the blade is also smaller, and the radial airflow disturbance on the axial airflow is also smaller. Changing the ratio of L to M to between 0.6 and 0.8 reduces the number of protrusions, effectively reducing the weight of the blade. The gradient difference between the radial airflow and the protrusions reduces the energy of the disturbance, thereby reducing the useless work done by the blade and improving the fan efficiency.

[0018] A preferred embodiment is that the airflow disturbance region is enclosed by a first arc line, a second arc line, a leading edge, and a trailing edge.

[0019] A preferred embodiment is that the outer surface of the protrusion is a convex arc surface.

[0020] This demonstrates that convex surfaces can better guide airflow.

[0021] A further design is to have a spherical protrusion with a radius R2 ranging from 0.005R to 0.02R.

[0022] A further option is to make the height h of the protrusion range from 0.5R2 to R2.

[0023] To achieve the second objective mentioned above, this utility model provides an air outlet device, including the aforementioned axial flow fan blade.

[0024] Therefore, the air outlet device can be an outdoor unit of an air conditioner. When this axial fan blade is applied to an outdoor unit of an air conditioner, it can improve the efficiency of the axial fan. While ensuring the air volume remains unchanged, it can effectively reduce the input power of the drive motor, reduce the power of the entire air conditioner to a certain extent, improve the energy efficiency of the air conditioner, effectively improve the aerodynamic characteristics of the axial fan blade of the outdoor unit of the air conditioner, effectively reduce the aerodynamic noise of the fan blade, and improve the comfort of users when using the air conditioner. Attached Figure Description

[0025] Figure 1 This is a front view of an embodiment of the axial flow fan blade of this utility model.

[0026] Figure 2 This is a front view of the blade in an embodiment of the axial flow fan blade of this utility model.

[0027] Figure 3 yes Figure 2A magnified view of a portion of point A in the middle.

[0028] Figure 4 This is a left view of an embodiment of the axial flow fan blade of this utility model.

[0029] Figure 5 This is a left view of the blade in an embodiment of the axial flow fan blade of this utility model.

[0030] Figure 6 This is the numerical simulation result of the axial flow fan blade embodiment of this utility model on a two-dimensional airfoil with different spacing ratios.

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0032] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are in no way intended to limit the present invention or its application or use. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present invention thorough and complete, and to fully express the scope of the present invention to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, the composition of materials, numerical expressions, and values ​​set forth in these embodiments should be interpreted as merely exemplary and not as limiting.

[0033] The terms "first," "second," and similar words used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as "including" or "comprising" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0034] In this invention, when a specific device is described as being located between a first device and a second device, an intermediary device may or may not exist between the specific device and the first or second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other devices without an intermediary device, or it may not be directly connected to the other devices but may have an intermediary device.

[0035] All terms used in this invention (including technical or scientific terms) have the same meaning as understood by one of ordinary skill in the art, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0036] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0037] The air outlet device in this embodiment is an air conditioner, which includes an indoor unit and an outdoor unit connected to each other. The outdoor unit includes an outdoor heat exchanger and an axial fan blade, with the axial fan blade positioned close to the outdoor heat exchanger.

[0038] See Figures 1 to 5 The axial flow fan blade includes a hub 1 and three blades 2. Each blade 2 is arranged around the circumference of the hub 1. Each blade 2 includes a leading edge 21, an outer edge 22, a trailing edge 23 and an inner edge 24 arranged sequentially around the circumference of the blade 2. The inner edge 24 is connected to the hub 1. The two sides of the blade 2 are a suction surface 25 and a pressure surface 26, respectively.

[0039] The suction surface 25 has an airflow disturbance region 31, a first smooth region 32, and a second smooth region 33. Along the radial direction of the blade 2, from the inner edge 24 to the outer edge 22, the first smooth region 32, the airflow disturbance region 31, and the second smooth region 33 are arranged sequentially. The blade 2 also includes a protrusion structure 5, which is located in the airflow disturbance region 31 and covers the entire airflow disturbance region 31.

[0040] The first smooth region 32 is separated from the airflow disturbance region 31 by the first arc line 41, and the second smooth region 33 is separated from the airflow disturbance region 31 by the second arc line 42. The airflow disturbance region 31 is enclosed by the first arc line 41, the second arc line 42, the leading edge 21 and the trailing edge 23.

[0041] The first arc line 41, the second arc line 42, and the outer edge 22 share a common center. The radius of the outer edge 22 is R. The radius of the first arc line 41 is greater than or equal to 0.4R, and the radius of the second arc line 42 is less than or equal to 0.8R. Preferably, the radius of the first arc line 41 is greater than or equal to 0.45R, and the radius of the second arc line 42 is less than or equal to 0.75R. Neither the first smooth region 32 nor the second smooth region 33 has any protrusions. The first arc line 41 and the second arc line 42 are both virtual lines. The first arc line 41 has its center at the center of the outer edge 22, and its radius is the minimum distance between the protrusion structure 5 and the center of the outer edge 22. The second arc line 42 has its center at the center of the outer edge 22, and its radius is the maximum distance between the protrusion structure 5 and the center of the outer edge 22.

[0042] The protruding structure 5 includes multiple protrusions 51, which protrude outward from the suction surface 25. The outer surface of the protrusion 51 is a convex arc surface. Preferably, the protrusion 51 is spherical, with a radius R2 in the range of 0.005R to 0.02R and a height h in the range of 0.5R2 to R2. Optionally, in other embodiments, the protrusion 51 may also be semi-ellipsoidal or have a streamlined surface, etc.

[0043] The protrusions 51 on each blade 2 are arranged in an array, and each row of protrusions 51 on the same blade 2 is arranged along an arc line, with each arc line sharing the same center with the first arc line 41. The interval L between two adjacent rows of protrusions 51 is in the range of 0.002R to 0.02R, and the interval M between two adjacent columns of protrusions 51 is in the range of 0.01R to 0.02R. The size and arrangement of the protrusions 51 are important parameters affecting the flow field. This invention restricts the relevant parameters and arrangement of the protrusions 51, enabling the fan blade to operate at its highest efficiency while simultaneously reducing drag.

[0044] Preferably, the ratio of L to M (i.e., the spacing ratio) is in the range of 0.1 to 0.8. By changing the ratio of L to M, the arrangement of the protrusions 51 on the suction surface 25 of the fan blades can be changed, thereby altering the flow field characteristics. When the fan blade speed of the outdoor unit is high, the centrifugal force is calculated using the formula F = mω. 2As can be seen from r, when the blade speed is high, the centrifugal force is large, resulting in greater radial disturbance and axial disturbance of the blade. This reduces the useful work done by the blade and thus affects the output airflow. By changing the ratio of L to M to between 0.1 and 0.5, the radial arrangement of protrusions 51 becomes denser. The protrusions 51 also indirectly form an uneven surface, which weakens the radial airflow disturbance after it passes over the protrusions 51 on the blade 2 surface, thereby achieving drag reduction and noise reduction. Furthermore, when the blade speed is low, the centrifugal force generated by the blade is also small, and the radial airflow disturbance on the axial airflow is also smaller. Changing the ratio of L to M to between 0.6 and 0.8 reduces the number of protrusions 51, effectively reducing the weight of the blade. The gradient difference between the radial airflow and the protrusions 51 reduces the energy of the disturbance, thereby reducing the useless work done by the blade and improving the efficiency of the fan.

[0045] Figure 6 Numerical simulation results are shown on a two-dimensional airfoil with different spacing ratios. As can be seen from the figure, the arrangement of protrusions 51 in the spacing ratio range of 0.1 to 0.8 has a good drag reduction effect.

[0046] As can be seen above, when an axial fan is in operation, under the action of centrifugal force, some airflow will flow along the radial direction of the blade towards the outer edge of the blade. The radial airflow along the blade will inevitably interfere with the axial airflow, thus generating significant disturbance in the airflow disturbance area on the suction surface of the blade. This increases the motor power, reduces the effective work done by the blade, and also reduces the airflow. Due to the interference of radial airflow, aerodynamic noise will also be generated on the blade surface, affecting user comfort.

[0047] This utility model's axial flow fan blade optimizes the blade's shape and structure. Without altering the original blade shape, it incorporates raised structures in areas of high turbulent kinetic energy to modify these areas, thereby reducing rotational noise. Simultaneously, it effectively improves the input power of the drive motor while maintaining airflow. Furthermore, the added raised structures increase the blade's strength and rigidity, reducing mechanical vibration and further lowering noise.

[0048] Furthermore, the airflow velocity is higher and the pressure is lower on the suction side. Adding a raised structure to the suction side can more effectively influence the airflow characteristics, reduce separation, and improve airflow adhesion, thereby increasing efficiency. On the pressure side of the fan blade, the airflow velocity is relatively lower and the pressure is higher, resulting in a more stable airflow that is less susceptible to the influence of microstructures. The effect of a raised structure on the pressure side is not significant on the suction side. Therefore, the axial flow fan blade of this invention uses a raised structure on the suction side to alter the airflow characteristics, achieving a more significant effect.

[0049] Meanwhile, if the entire suction surface of the blade is covered with raised structures, it will not only increase the complexity of the manufacturing process and thus increase manufacturing costs, but also make the surface cleaning more difficult, especially in humid or dusty environments, where dirt can easily accumulate on the raised structures, affecting the performance of the blades. Excessive raised structures can also lead to uneven airflow distribution and increased local airflow disturbance, potentially causing more eddies and separation, thus reducing the overall efficiency of the blades. This invention addresses this by arranging raised structures in areas of significant airflow disturbance—areas with greater turbulence and a greater impact on the blades. Compared to covering the entire surface with raised structures, this effectively reduces the number of processes required while achieving the same effect as covering the entire surface with raised structures, thus saving costs.

[0050] When applied to an outdoor air conditioning unit, this axial fan blade can improve the efficiency of the axial fan. While ensuring the air volume remains constant, it effectively reduces the input power of the drive motor, thereby reducing the overall power of the air conditioner and improving its energy efficiency. It can also effectively improve the aerodynamic characteristics of the axial fan blade in the outdoor air conditioning unit, effectively reduce the aerodynamic noise of the fan blade, and improve the user's comfort during air conditioning use.

[0051] Furthermore, the number of blades can be three or more, with each blade arranged circumferentially along the hub. The shape, size, and number of blades can all be changed as needed. The shape, size, and arrangement of the protrusions on each blade can also be changed as needed. Alternatively, the protrusions on at least one blade can be arranged in an array. The above modifications can also achieve the purpose of this utility model.

[0052] Finally, it should be emphasized that the above are only preferred embodiments of the present utility model and are not intended to limit the present utility model. For those skilled in the art, the present utility model can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., 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. An axial flow fan blade, comprising a hub and a plurality of blades, wherein each blade is arranged circumferentially along the hub, and each blade includes a leading edge, an outer edge, a trailing edge and an inner edge arranged sequentially along the circumferential direction of the blade, wherein the inner edge is connected to the hub, and the two sides of the blade are a suction surface and a pressure surface, respectively. Its features are: The suction surface has an airflow disturbance region, a first smooth region, and a second smooth region. Along the radial direction of the blade, from the inner edge to the outer edge, the first smooth region, the airflow disturbance region, and the second smooth region are arranged sequentially. The first smooth region is separated from the airflow disturbance region by a first arc line, and the second smooth region is separated from the airflow disturbance region by a second arc line. The first arc line, the second arc line, and the outer edge share the same center. The radius of the outer edge is R. The radius of the first arc line is greater than or equal to 0.4R, and the radius of the second arc line is less than or equal to 0.8R. The blade also includes a protruding structure located in the airflow disturbance area and covering the airflow disturbance area. The protruding structure includes multiple protrusions that protrude outward from the suction surface.

2. The axial flow fan blade according to claim 1, characterized in that: The radius of the first arc is greater than or equal to 0.45R; and / or The radius of the second arc is less than or equal to 0.75R.

3. The axial flow fan blade according to claim 1, characterized in that: At least one of the protrusions on the blade is arranged in an array; The rows of protrusions on the same blade are arranged along an arc line, and each arc line shares the same center with the first arc line.

4. The axial flow fan blade according to claim 3, characterized in that: The spacing L between two adjacent rows of protrusions is in the range of 0.002R to 0.02R; and / or The interval M between two adjacent columns of protrusions is in the range of 0.01R to 0.02R.

5. The axial flow fan blade according to claim 4, characterized in that: The ratio of L to M is in the range of 0.1 to 0.

8.

6. The axial flow fan blade according to any one of claims 1 to 5, characterized in that: The airflow disturbance region is enclosed by the first arc line, the second arc line, the leading edge, and the trailing edge.

7. The axial flow fan blade according to any one of claims 1 to 5, characterized in that: The outer surface of the protrusion is a convex arc surface.

8. The axial flow fan blade according to claim 7, characterized in that: The protrusion is spherical, and the radius R2 of the protrusion is in the range of 0.005R to 0.02R.

9. The axial flow fan blade according to claim 8, characterized in that: The height h of the protrusion is in the range of 0.5R2 to R2.

10. An air outlet device, characterized in that, Including the axial flow fan blades as described in any one of claims 1 to 9.

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