Axial flow fan and air conditioner having same

Abstract

An axial flow fan and an air conditioner having the axial flow fan. The fan comprises a hub (1) and a blade (2), wherein the blade (2) is arranged on the hub (1); the blade (2) comprises a blade root (21) close to the hub (1) in the radial direction and an outer edge (22) away from the hub (1); the blade (2) is provided with a bending structure (25) between the blade root (21) and the outer edge (22); and the angle between the blade chord at the blade root (21) and the plane of rotation of the axial flow fan is greater than the angle between the blade chord at the outer edge (22) and the plane of rotation of the axial flow fan.

Description

Axial flow fan and air conditioner having the same

[0001] This application claims priority to the Chinese patent application filed on December 29, 2023, with application number CN202311861840.2. The full text of the above-mentioned Chinese patent application is incorporated into this application by reference. Technical Field

[0002] The present invention relates to the field of axial flow fans, and in particular provides an axial flow fan and an air conditioner having the axial flow fan. Background Art

[0003] Currently, both residential and commercial air conditioner outdoor units on the market use axial-flow fans as their power source, generating high-speed gas flow to transport energy to the heat exchanger. When using these devices, users experience significant noise due to fan vibration, vortices generated by the blades, and disturbances in the airflow, impacting the user experience. Currently, air conditioner outdoor units are evolving towards higher efficiency and quieter operation, but current solutions are unable to ensure both sufficient airflow to transport energy to the heat exchanger and smoother airflow between the fan blades within a limited space, thereby improving fan efficiency and reducing fluid noise.

[0004] At present, in order to improve the efficiency of the axial flow fan of the air conditioner outdoor unit and reduce the noise, some local processing methods of the axial flow fan blades are mostly adopted in the market, such as serrated trailing edge, blade tip winglet, and outer edge flange, and there are few technical solutions that are innovative as a whole.

[0005] Accordingly, the art requires a new axial flow fan and an air conditioner having the same to solve the above problems.

[0006] Summary of the Invention

[0007] The present invention aims to solve the above technical problem, that is, to solve the problem that the existing axial flow fan cannot ensure that the noise can be reduced while providing sufficient air volume.

[0008] In a first aspect, the present invention provides an axial flow fan, characterized in that the axial flow fan comprises: a hub; blades, the blades being arranged on the hub, the blades comprising a blade root portion close to the hub in the radial direction and an outer edge away from the hub, the blades being provided with a bending structure between the blade root portion and the outer edge; wherein an angle between a blade chord at the blade root portion and a rotation plane of the axial flow fan is greater than an angle between a blade chord at the outer edge and the rotation plane of the axial flow fan.

[0009] In the optional technical solution of the above-mentioned axial flow fan, the bending structure includes a first end close to the blade root in the radial direction of the blade, and a second end away from the blade root in the radial direction of the blade, and the first end and the second end are spaced apart by a distance L1 in the radial direction.

[0010] In an optional technical solution of the above-mentioned axial flow fan, the distance between the blade root and the first end is recorded as L2, and the distance between the second end and the outer edge is recorded as L3, wherein L1<|L3-L2|.

[0011] When the above technical solution is adopted, it helps to optimize the load distribution of the blades in specific areas, reduce stress concentration, and extend the service life. The bending structure can act as an interference element for the airflow, changing the flow characteristics in specific areas. This can be the control of flow phenomena such as vortex formation, separation, and reattachment, thereby improving the aerodynamic performance of the blades. The local bending structure will interfere with the sound pattern generated when the fluid flows through the blades, especially in areas where the blade speed is faster, which can significantly reduce the noise emitted. At the same time, this design can also reduce the resistance of the airflow on the blade surface, thereby improving the efficiency of the fan. In addition, this design helps to reduce the use of materials because the width of the bending structure is smaller, which may help to reduce manufacturing costs, and also help to reduce the weight of the fan, making the device lighter.

[0012] In the optional technical solution of the above axial flow fan, L2>L3.

[0013] In an optional technical solution of the above-mentioned axial flow fan, the bending structure extends from the leading edge of the blade to the trailing edge of the blade.

[0014] In the optional technical solution of the above-mentioned axial flow fan, the bending structure separates the blades into a first blade and a second blade, the first blade is closer to the hub than the second blade, and the bending structure bends from the first blade to the side of the negative pressure surface of the first blade.

[0015] In an optional technical solution of the above-mentioned axial flow fan, the bending structure bends from the second blade toward a side of the positive pressure surface of the second blade.

[0016] In an optional technical solution of the above-mentioned axial flow fan, each of the blades is provided with the bending structure.

[0017] In an optional technical solution of the above-mentioned axial flow fan, the number of the bending structure on each of the blades is one.

[0018] In another aspect, the present invention further provides an air conditioner, comprising the axial flow fan described in any one of the above embodiments.

[0019] The axial flow fan of the present invention includes a hub and blades, wherein the blades are arranged on the hub, and the blades include a blade root portion close to the hub in the radial direction and an outer edge away from the hub. The blades are provided with a bending structure between the blade root portion and the outer edge, wherein the angle between the blade chord at the blade root portion and the rotation plane of the axial flow fan is greater than the angle between the blade chord at the outer edge and the rotation plane of the axial flow fan.

[0020] In an axial fan, the relative motion between the blades and the fluid (such as air) generates power, pushing the fluid forward. The angle between the blade chord at the root and the axial fan's rotating plane is greater than the angle between the blade chord at the outer edge and the axial fan's rotating plane. This means that the blades at the root are more inclined and can interact with the fluid more effectively, accelerating the airflow and thus increasing the air volume. The noise mainly comes from the airflow vibration and vortex generation when the axial fan is working. When the angle between the blade chord at the root and the axial fan's rotating plane is greater than the angle between the blade chord at the outer edge and the axial fan's rotating plane, and a bending structure is designed between the blade root and the outer edge, the airflow at the blade root can be accelerated, while the airflow at the outer edge is relatively slow. This distribution can reduce the unevenness of the flow velocity at the blade tip, reduce the intensity of the blade tip vortex, avoid violent fluctuations and vibrations in the airflow, and thus effectively reduce noise. In general, the design of this bending structure improves the fan's airflow dynamic performance by optimizing the installation angle of the blade, thereby achieving the goal of reducing noise while providing sufficient air volume.

[0021] The presence of the tip vortex is the main cause of the broadband noise caused by the rotation of blade 2, and the tip vortex is mainly caused by the pressure difference on both sides of the blade. Since the installation angle of the traditional fan is consistent throughout the blade, the low-pressure area on the suction surface of the parent fan is larger at the same installation angle, resulting in a large pressure difference on both sides of the blade, which further leads to a larger intensity and shape of the tip vortex, resulting in greater noise. The axial flow fan of the present invention can significantly reduce noise. Compared with the wood fan, at the same air volume, except for the air volume <2500m3 / h, the noise of the axial flow fan of the present invention is increased compared with the parent fan, and the noise at other speeds is significantly reduced, with a maximum difference of more than 2dB, which just covers the working range of the air conditioner. At the same speed, within the working range of the air conditioner outdoor unit, the axial flow air volume of the present invention is significantly improved compared with the parent fan. At the same air volume, the power of the axial flow fan of the present invention is not increased compared with the parent fan, and is basically the same as the parent fan. Compared with the parent fan, the pressure resistance of the axial flow fan of the present invention is greatly improved at small air volumes, and the pressure resistance is also partially improved at large air volumes. It can be seen that the pressure resistance of the axial flow fan of the present invention is improved within the working air volume range. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0023] FIG1 is a front view of an axial flow fan of the present invention;

[0024] FIG2 is a perspective view of the axial flow fan of the present invention;

[0025] FIG3 is a schematic structural diagram of the installation angle at the blade root of the axial flow fan of the present invention;

[0026] FIG4 is a schematic structural diagram of the installation angle at the outer edge of the axial flow fan of the present invention;

[0027] FIG5 is a comparison diagram of the suction surface pressure of the axial flow fan of the present invention and the parent fan;

[0028] FIG6 is a comparison diagram of the vortex distribution of the axial flow fan of the present invention and the parent fan;

[0029] FIG7 is a noise comparison diagram of the axial flow fan of the present invention and the parent fan under the same air volume;

[0030] FIG8 is a comparison diagram of the air volume of the axial flow fan of the present invention and the parent fan at the same speed;

[0031] FIG9 is a power comparison diagram of the axial flow fan of the present invention and the parent fan under the same air volume;

[0032] FIG10 is an analysis of the measured performance curves of the axial flow fan of the present invention and the parent fan.

[0033] Explanation of the reference numerals: 1-hub; 2-blade; 21-blade root; 22-outer edge; 23-leading edge; 24-trailing edge; 25-bending structure; 251-first end; 252-second end; 26-first blade; 261-negative pressure surface; 27-second blade; 271-positive pressure surface. DETAILED DESCRIPTION

[0034] Preferred embodiments of the present invention are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely intended to illustrate the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. Those skilled in the art may adjust these embodiments as needed to suit specific applications.

[0035] It should be noted that, in the description of this invention, unless otherwise expressly specified or limited, the terms "connected" and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can be directly connected or indirectly connected through an intermediary. Those skilled in the art will understand the specific meanings of these terms in this invention based on the specific circumstances. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0036] As shown in Figures 1 to 4, in order to solve the problem that the axial flow fan cannot ensure that the noise can be reduced while providing sufficient air volume. The present invention provides an axial flow fan, which includes a hub 1 and blades 2, and the blades 2 are arranged on the hub 1, wherein the present invention does not limit the number of blades 2. Optionally, the number of blades 2 is three, and the three blades 2 are evenly spaced and distributed on the circumference of the hub 1. Of course, the blades 2 can also be other numbers, and the specific number can be selected according to the specific application scenario. The blades 2 include a blade root 21 close to the hub 1 in the radial direction and an outer edge 22 away from the hub 1. The blades 2 are provided with a bending structure 25 between the blade root 21 and the outer edge 22, wherein the angle between the blade chord at the blade root 21 and the rotation plane of the axial flow fan is greater than the angle between the blade chord at the outer edge 22 and the rotation plane of the axial flow fan. For ease of explanation, the angle between the blade chord at the blade root 21 and the axial fan's rotation plane is referred to as a first installation angle α1, and the angle between the blade chord at the outer edge 22 and the axial fan's rotation plane is referred to as a second installation angle α2. It will be understood that the axial fan's rotation plane is a plane perpendicular to the axis of the hub 1.

[0037] In an axial flow fan, the relative motion between the blade 2 and the fluid (such as air) generates power, pushing the fluid forward. In the technical solution of the present invention, the first installation angle α1 at the blade root is larger than the second installation angle α2 at the outer edge 22, which means that the blade 2 at the blade root 21 is more inclined, and can more effectively interact with the fluid, accelerate the airflow, and thus increase the air volume; while the noise mainly comes from the airflow vibration and vortex generation when the axial flow fan is working. When the first installation angle α1 is greater than the second installation angle α2, a bending structure 25 is designed between the blade root 21 and the outer edge 22, which can accelerate the airflow at the blade root, while the airflow at the outer edge 22 is relatively slow. This distribution can reduce the unevenness of the flow velocity at the tip of the blade 2, reduce the intensity of the blade tip vortex, avoid violent fluctuations and vibrations of the air flow, and thus effectively reduce noise. In general, the design of this bending structure 25 improves the airflow dynamic performance of the fan by optimizing the installation angle of the blade 2, thereby achieving the purpose of reducing noise while providing sufficient air volume.

[0038] As shown in Figures 5 and 6, (a) in Figure 5 is the axial flow fan of the present invention, (b) is the parent fan, and (c) in Figure 6 is the axial flow fan of the present invention, and (d) is the parent fan. The existence of tip vortex is the main cause of broadband noise caused by blade rotation, and the tip vortex is mainly caused by the pressure difference on both sides of the blade. Since the installation angle of the entire blade of the traditional fan is consistent, the low-pressure area of ​​the suction surface of the parent fan at the same installation angle is larger, resulting in a large pressure difference on both sides of the blade, further resulting in greater intensity and shape of the tip vortex, resulting in greater noise. The axial flow fan of the present invention can significantly reduce noise. The suction surface pressure comparison diagram is shown in Figure 1, and the vortex distribution comparison diagram is shown in Figure 2.

[0039] As shown in FIG7 , under the same air volume, when the air removal volume is less than 2500 m3 / h, the noise of the axial flow fan of the present invention is slightly higher than that of the parent fan, while the noise at other speeds is significantly reduced, with the maximum difference being more than 2 dB, which just covers the working range of the air conditioner.

[0040] As shown in FIG8 , at the same rotation speed, within the operating range of the air conditioner outdoor unit, the axial flow air volume of the present invention is significantly improved compared to that of the parent fan.

[0041] As shown in FIG9 , under the same air volume, the power of the axial flow fan of the present invention is not increased compared with the parent fan, and is basically the same as that of the parent fan.

[0042] As shown in Figure 10, Figure 10 is the speed PQ curve corresponding to the same working air volume. Compared with the parent fan, the pressure resistance of the axial flow fan of the present invention at small and medium air volumes is greatly improved, and the pressure resistance is also partially improved at large air volumes. It can be seen that the pressure resistance of the axial flow fan of the present invention is improved within the working air volume range.

[0043] In summary, the axial flow fan of the present invention has significant improvements in reducing noise, increasing air volume, and improving pressure resistance.

[0044] As a possible embodiment, the bent structure 25 includes a first end 251 radially proximal to the blade root 21 of the blade 2, and a second end 252 radially distal to the blade root 21 of the blade 2. A radial spacing L1 is provided between the first end 251 and the second end 252. The first end 251 and the second end 252 described above may also be referred to as the radial ends of the bent structure 25 of the blade 2. Optionally, the entire width of the bent structure 25 is equal. The first end 251 and the second end 252 of the bent structure may both be arc-shaped.

[0045] Since there is a radial distance between the first end 251 and the second end 252, that is, the bending structure 25 has a certain width in the radial direction, this bending structure 25 allows the airflow to have a certain width in the radial direction of the bending structure 25, so that the airflow will not be too concentrated, thereby increasing the overall air volume.

[0046] As a possible implementation, the distance between the blade root 21 and the first end 251 is recorded as L2, and the distance between the second end 252 and the outer edge 22 is recorded as L3, wherein L1<|L3-L2|.

[0047] When L1<|L3-L2|, this means that the effect of the bending structure 25 on the blade 2 is local. This helps to optimize the load distribution of the blade 2 in a specific area, reduce stress concentration, and extend the service life. The bending structure 25 can act as an interference element of the airflow, changing the flow characteristics in a specific area. This can be the control of flow phenomena such as vortex formation, separation and reattachment, thereby improving the aerodynamic performance of the blade 2. The local bending structure 25 will interfere with the sound pattern generated when the fluid flows through the blade 2, especially in areas where the speed of the blade 2 is faster, which can significantly reduce the noise emitted. At the same time, this design can also reduce the resistance of the airflow on the surface of the blade 2, thereby improving the efficiency of the fan. In addition, this design helps to reduce the use of materials because the width of the bending structure 25 is small, which can help to reduce manufacturing costs, and also help to reduce the weight of the fan, making the device lighter.

[0048] Optionally, the bending structure 25 is provided in the radial middle of the blade 2. Since the airflow velocity in the middle of the blade 2 is usually higher than that in the edge portion, the noise problem may be more serious, and therefore, this design can effectively control the noise.

[0049] As a possible embodiment, L2>L3 in the present invention. As an alternative embodiment, L2<L3 can also be designed. In the design of an axial flow fan, the position and size of the bending structure 25 on the blade 2 can be reasonably controlled by adjusting the distances between L1, L2, and L3 according to the specific application scenario.

[0050] As a possible embodiment, the bending structure 25 extends from the leading edge 23 of the blade 2 to the trailing edge 24 of the blade 2. It is understood that the leading edge 23 of the blade 2 refers to the portion of the blade 2 that the airflow first contacts, and the trailing edge 24 of the blade 2 refers to the portion of the blade 2 that the airflow last leaves. The leading edge 23 and the trailing edge 24 of the blade 2 are relative to the two sides of the blade 2 in the circumferential direction.

[0051] The curved structure 25 extending from the leading edge 23 to the trailing edge 24 of blade 2 effectively controls airflow across the entire blade 2, helping to reduce vortex formation and, in turn, improve fan efficiency and reduce noise. Furthermore, the curved structure 25 extends along the entire length of blade 2, improving overall performance, including increasing aerodynamic efficiency, reducing aerodynamic noise, and delaying stall. Furthermore, this arrangement helps mitigate stress and vibration caused by centrifugal and aerodynamic forces during operation, thereby enhancing the stability and durability of the device.

[0052] As a possible embodiment, the bending structure 25 separates the blade 2 into a first blade 26 and a second blade 27. The first blade 26 is closer to the hub 1 than the second blade 27. The bending structure 25 bends from the first blade 26 toward the negative pressure surface 261 of the first blade 26. In other words, the portion from the root 21 of the blade 2 to the first end 251 of the bending structure 25 constitutes the first blade 26, and the portion from the second end 252 of the bending structure 25 to the outer edge 22 of the blade 2 constitutes the second blade 27.

[0053] Among them, the negative pressure surface 261 and the positive pressure surface 271 of the blade 2 are relative to the two sides in the thickness direction of the blade 2. The negative pressure surface 261 of the blade 2 is specifically the side that generates lower pressure when the airflow flows through the blade 2, and the positive pressure surface 271 of the blade 2 is specifically the side that generates higher pressure when the airflow flows through the blade 2.

[0054] As a possible implementation, the bending structure 25 bends from the second blade 27 toward one side of the positive pressure surface 271 of the second blade 27 .

[0055] This arrangement allows the bending structure 25 to bend toward the different pressure surfaces of the first blade 26 and the second blade 27, respectively. This improves the structural strength of blade 2, reduces vibration, and enhances the stability of the device. This design also allows airflow to flow more effectively along blade 2, making better use of the positive and negative pressure surfaces of blade 2, reducing energy loss and thus improving the performance of the entire device. In other words, this design helps optimize the flow of air over blade 2, improve the aerodynamic efficiency of blade 2, reduce noise, and enhance the stability and performance of the device.

[0056] As a possible embodiment, each blade 2 is provided with a bent structure 25. The presence of the bent structure 25 on each blade 2 can enhance the rigidity and vibration resistance of the blade 2, reduce vibration during operation, and thus improve the stability of the device. This also facilitates manufacturing and reduces production costs.

[0057] As a possible implementation, the number of the bending structure 25 on each blade 2 is one.

[0058] This arrangement reduces design and manufacturing complexity, lowers manufacturing costs, allows for better control of the manufacturing process, and improves manufacturing precision and consistency, all of which are crucial for device performance and stability. Furthermore, a single stepped structure on each blade 2 is sufficient to alter the airflow path, improving the blade's aerodynamic efficiency, reducing noise, and enhancing device stability and performance. It also reduces mechanical stress on the blade, increasing its reliability and service life.

[0059] As a possible embodiment, the trailing edge 24 of the blade 2 of the present invention is provided with a wavy structure. This effectively changes the airflow path, making the airflow on the blade 2 smoother, further reducing the generation of vortices and turbulence, thereby improving the aerodynamic efficiency of the entire device and helping to reduce the noise caused by the vortices and turbulence generated by the airflow on the blade 2.

[0060] In another aspect, the present invention further provides an air conditioner comprising the axial flow fan described in any of the aforementioned embodiments. Specifically, the axial flow fan can be mounted on an outdoor unit of the air conditioner. The air conditioner having the axial flow fan can improve the fan's airflow dynamics, thereby achieving the goal of providing sufficient air volume while reducing noise.

[0061] It should be noted that the above-mentioned embodiments are only used to illustrate the principles of the present invention and are not intended to limit the scope of protection of the present invention. Without departing from the principles of the present invention, those skilled in the art can adjust the above-mentioned structure so that the present invention can be applied to more specific application scenarios.

[0062] For example, as an alternative embodiment, although the present invention is introduced as having a bending structure 25 on each blade 2, this is not intended to limit the scope of protection of the present invention. For example, a bending structure 25 can be provided on every other blade 2, etc. These adjustments do not deviate from the principles of the present invention and are within the scope of protection of the present invention.

[0063] For example, as an alternative embodiment, although the present invention is introduced as having one bending structure 25 on each blade 2, this is not intended to limit the scope of protection of the present invention. For example, the number of bending structures 25 on each blade 2 can be designed to be other numbers according to the specific application scenario, such as two or three, etc. These adjustments do not deviate from the principles of the present invention and are within the scope of protection of the present invention.

[0064] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. An axial flow fan, characterized in that, The axial flow fan includes: a hub; blades, which are arranged on the hub. The blades include a blade root portion close to the hub in the radial direction and an outer edge far from the hub. A bending structure is provided between the blade root portion and the outer edge of the blade; wherein, the included angle between the chord line at the blade root portion and the rotation plane of the axial flow fan is greater than the included angle between the chord line at the outer edge and the rotation plane of the axial flow fan.

2. The axial flow fan according to claim 1, wherein the bending structure includes a first end close to the blade root portion in the radial direction of the blade, and also includes a second end far from the blade root portion in the radial direction of the blade. A distance L1 is left between the first end and the second end in the radial direction.

3. The axial flow fan according to claim 2, wherein the distance between the blade root portion and the first end is denoted as L2, and the distance between the second end and the outer edge is denoted as L3. Among them, L1 < |L3 - L2|.

4. The axial flow fan according to claim 3, characterized in that L2 > L3.

5. The axial flow fan according to claim 1, wherein the bending structure extends from the leading edge of the blade to the trailing edge of the blade.

6. The axial flow fan according to claim 5, wherein the bending structure divides the blade into a first blade and a second blade. The first blade is closer to the hub than the second blade. The bending structure bends from the first blade to the side of the negative pressure surface of the first blade.

7. The axial flow fan according to claim 6, wherein the bending structure bends from the second blade to the side of the positive pressure surface of the second blade.

8. The axial flow fan according to claim 1, wherein each of the blades is provided with the bending structure.

9. The axial flow fan according to claim 8, wherein the number of the bending structures on each of the blades is one.

10. An air conditioner, characterized in that, The air conditioner includes the axial flow fan according to any one of claims 1 to 9.

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