Axial flow fan and air conditioner with same

Abstract

The invention relates to the field of axial flow fans, in particular to an axial flow fan and an air conditioner with the axial flow fan, and aims to solve the problem that an existing axial flow fan cannot reduce noise on the basis of providing enough air volume. In order to achieve the purpose, the fan comprises a hub and blades, the blades are arranged on the hub, each blade comprises a blade root part close to the hub in the radial direction and an outer edge away from the hub, and a bent structure is arranged between the blade root part and the outer edge of each blade. The included angle between the blade chord at the blade root and the rotating plane of the axial fan is larger than the included angle between the blade chord at the outer edge and the rotating plane of the axial fan. By means of the arrangement mode, the airflow dynamic performance of the fan is improved, and therefore the purpose that noise is reduced while enough air volume is provided is achieved.

Description

Technical Field

[0001] The present invention relates to the field of axial fans, and particularly provides an axial fan and an air conditioner having the axial fan. Background Art

[0002] Currently, axial fans are used as the power source for both household air conditioner outdoor units and commercial air conditioner outdoor units in the market to generate high-speed flowing gas for energy transport to the heat exchanger. When users use these devices, relatively large noise will be generated due to the vibration of the fan, the eddy current generated by the fan blades, and the disturbance of the air flow in the flow channel, which affects the user experience. At present, air conditioner outdoor unit devices have developed towards the market demands of high efficiency and low noise. However, the current solutions cannot ensure both sufficient air volume for energy transport to the heat exchanger and smoother air flow between the fan blades in a limited space, so as to improve the operating efficiency of the fan and reduce fluid noise at the same time.

[0003] Currently, in order to improve the efficiency of the axial fan of the air conditioner outdoor unit and reduce noise in the market, local treatment methods for the axial fan blades are mostly adopted, such as using serrated trailing edges, winglets at the tip, and flanging at the outer edge. There are few innovative technical solutions for the whole.

[0004] Correspondingly, there is a need in the art for a new axial fan and an air conditioner having the axial fan to solve the above problems. Summary of the Invention

[0005] The present invention aims to solve the above technical problems, that is, to solve the problem that the existing axial fan cannot ensure reducing noise while providing sufficient air volume.

[0006] In a first aspect, the present invention provides an axial fan, characterized in that the axial fan includes: a hub; blades, the blades are arranged on the hub, the blades include a root part close to the hub in the radial direction and an outer edge far from the hub, and a bending structure is provided between the root part and the outer edge of the blade; wherein, the angle between the chord of the root part and the rotation plane of the axial fan is greater than the angle between the chord of the outer edge and the rotation plane of the axial fan.

[0007] In an alternative technical solution of the above axial fan, the bending structure includes a first end close to the root part in the radial direction of the blade, and also includes a second end far from the root part in the radial direction of the blade, and a distance L1 is left between the first end and the second end in the radial direction.

[0008] In an alternative technical solution of the above axial fan, the distance between the root part and the first end is denoted as L2, and the distance between the second end and the outer edge is denoted as L3, wherein, L1 < |L3 - L2|.

[0009] In the case of adopting the above technical solution, it helps to optimize the load distribution of the blade in a specific area, reduce stress concentration, and extend the service life. The bending structure can be used as a flow disturbance element to change 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. The local bending structure will interfere with the sound pattern generated when the fluid flows through the blade, especially in the area where the blade speed is relatively high, which can significantly reduce the emitted noise. 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 small, which may help to reduce the manufacturing cost and also help to reduce the weight of the fan, making the device more portable.

[0010] In the alternative technical solution of the above axial flow fan, L2 > L3.

[0011] In the alternative technical solution of the above axial flow fan, the bending structure extends from the leading edge of the blade to the trailing edge of the blade.

[0012] In the alternative technical solution of the above axial flow fan, the bending structure divides the blade into a first blade and a second blade. The first blade is closer to the hub relative to the second blade, and the bending structure bends from the first blade to the side of the negative pressure surface of the first blade.

[0013] In the alternative technical solution of the above axial flow fan, the bending structure bends from the second blade to the side of the positive pressure surface of the second blade.

[0014] In the alternative technical solution of the above axial flow fan, the bending structure is provided on each of the blades.

[0015] In the alternative technical solution of the above axial flow fan, the number of the bending structures on each blade is one.

[0016] On the other hand, the present invention also provides an air conditioner, which includes the axial flow fan described in any of the above embodiments.

[0017] The axial flow fan of the present invention includes a hub and blades. The blades 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. Among them, the angle between the chord line at the blade root portion and the rotation plane of the axial flow fan is greater than the angle between the chord line at the outer edge and the rotation plane of the axial flow fan.

[0018] In an axial flow fan, the relative movement between the blades and the fluid (such as air) generates power to push the fluid forward. The angle between the chord of the blade at the root and the rotation plane of the axial flow fan is greater than the angle between the chord of the blade at the outer edge and the rotation plane of the axial flow fan. This means that the blades at the root are more inclined and can interact with the fluid more effectively, accelerating the air flow and thus increasing the air volume. Noise mainly comes from the air flow vibration and vortex generation during the operation of the axial flow fan. When the angle between the chord of the blade at the root and the rotation plane of the axial flow fan is greater than the angle between the chord of the blade at the outer edge and the rotation plane of the axial flow fan, and at the same time, a bending structure is designed between the root and the outer edge, the air flow at the root can be accelerated while the air flow at the outer edge is relatively slow. This distribution can reduce the non-uniformity of the flow velocity at the blade tip, reduce the intensity of the tip vortex, and avoid the violent fluctuation and vibration of the air flow, thereby effectively reducing the noise. Generally speaking, the design of this bending structure optimizes the installation angle of the blades, improves the air flow dynamic performance of the fan, and thus achieves the purpose of reducing noise while providing sufficient air volume.

[0019] The existence of the tip vortex is the main cause of the broadband noise generated 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 entire blade of the traditional fan is the same, the low-pressure area on the suction surface of the parent fan is larger under the same installation angle, resulting in a larger pressure difference on both sides of the blade, further leading to a larger intensity and shape of the tip vortex and resulting in greater noise. However, the axial flow fan of the present invention can significantly reduce noise. Compared with the parent fan, at the same air volume, except when the air volume is <2500 m3 / h, the noise of the axial flow fan of the present invention increases compared with the parent fan, and the noise at other speeds is significantly reduced, with a maximum difference of more than 2 dB, which just covers the working range of the air conditioner. At the same speed, within the working range of the outdoor unit of the air conditioner, the axial flow air volume of the present invention is significantly increased compared with the parent fan. At the same air volume, the power of the axial flow fan of the present invention does not increase compared with the parent fan and is basically the same as that of the parent fan. Compared with the parent fan, the axial flow fan of the present invention has a great improvement in the pressure resistance at small and medium air volumes, and also has a partial improvement in the pressure resistance at large air volumes. It can be seen that the axial flow fan of the present invention has improved pressure resistance within the working air volume range. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings, in which:

[0021] Figure 1 is the front view of the axial flow fan of the present invention;

[0022] Figure 2 is the three-dimensional external view of the axial flow fan of the present invention;

[0023] Figure 3 is the structural schematic diagram of the installation angle at the root of the blade of the axial flow fan of the present invention;

[0024] Figure 4 is a schematic structural diagram of the installation angle at the outer edge of the axial flow fan of the present invention;

[0025] Figure 5 is a comparison diagram of the suction surface pressure between the axial flow fan of the present invention and the parent fan;

[0026] Figure 6 is a comparison diagram of the vortex distribution between the axial flow fan of the present invention and the parent fan;

[0027] Figure 7 is a comparison diagram of the noise at the same air volume between the axial flow fan of the present invention and the parent fan;

[0028] Figure 8 is a comparison diagram of the air volume at the same rotational speed between the axial flow fan of the present invention and the parent fan;

[0029] Figure 9 is a comparison diagram of the power at the same air volume between the axial flow fan of the present invention and the parent fan;

[0030] Figure 10 is an analysis of the measured results of the performance curves of the axial flow fan of the present invention and the parent fan.

[0031] Description of reference numerals:

[0032] 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 implementation manners

[0033] The preferred implementation manners of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these implementation manners are only used to explain the technical principle of the present invention and are not intended to limit the protection scope of the present invention. Those skilled in the art can make adjustments according to needs to adapt to specific application scenarios.

[0034] It should be noted that in the description of the present invention, unless otherwise clearly specified and defined, the terms "connected" and "linked" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0035] As Figures 1 to 4As shown, in order to solve the problem that an axial flow fan cannot ensure sufficient air volume while reducing noise, the present invention provides an axial flow fan, which includes a hub 1 and blades 2. The blades 2 are arranged on the hub 1. Among them, 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 in the circumferential direction of the hub 1. Of course, the number of blades 2 can also be other numbers, and the specific number can be selected according to the specific application scenario. Among them, the blade 2 includes a blade root 21 close to the hub 1 in the radial direction and an outer edge 22 far from the hub 1. The blade 2 is provided with a bending structure 25 between the blade root 21 and the outer edge 22. Among them, the angle between the chord line at the blade root 21 and the rotation plane of the axial flow fan is greater than the angle between the chord line at the outer edge 22 and the rotation plane of the axial flow fan. For the convenience of description, the angle between the chord line at the blade root 21 and the rotation plane of the axial flow fan is denoted as the first installation angle α1 below, and the angle between the chord line at the outer edge 22 and the rotation plane of the axial flow fan is denoted as the second installation angle α2. It can be understood that the rotation plane of the axial flow fan is a plane perpendicular to the axis of the hub 1.

[0036] In an axial flow fan, the relative movement between the blade 2 and the fluid (such as air) generates power to push 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 interact with the fluid more effectively, accelerating the air flow and thus increasing the air volume; while the noise mainly comes from the air flow vibration and vortex generation during the operation of the axial flow fan. When the first installation angle α1 is greater than the second installation angle α2 and a bending structure 25 is designed between the blade root 21 and the outer edge 22 at the same time, the air flow at the blade root can be accelerated, while the air flow at the outer edge 22 is relatively slow. This distribution can reduce the non-uniformity of the flow velocity at the tip of the blade 2, reduce the intensity of the tip vortex, and avoid the violent fluctuation and vibration of the air flow, thereby effectively reducing the noise. Generally speaking, the design of this bending structure 25 optimizes the installation angle of the blade 2, improves the air flow dynamic performance of the fan, and thus achieves the purpose of reducing noise while providing sufficient air volume.

[0037] As Figure 5 and Figure 6 shown, Figure 5 Figure (a) is the axial flow fan of the present invention, and (b) is the mother fan. Figure 6Figure (c) shows the axial flow fan of the present invention, and figure (d) shows the parent fan. The existence of tip vortices is the main cause of blade rotation broadband noise, and tip vortices are 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 the same, the low-pressure area on the suction surface of the parent fan is larger under the same installation angle, resulting in a large pressure difference on both sides of the blade, further leading to a larger tip vortex intensity and shape, and resulting in greater noise. However, the axial flow fan of the present invention can significantly reduce noise. The pressure comparison diagram of the suction surface is as shown in Figure 1 , and the vortex distribution comparison diagram is as shown in Figure 2 .

[0038] As shown in Figure 7 , at the same air volume, except when the air volume is <2500 m3 / h, the noise of the axial flow fan of the present invention increases compared with that of the parent fan, and the noise at other speeds is significantly reduced, with a maximum difference of more than 2 dB, which exactly covers the working range of the air conditioner.

[0039] As shown in Figure 8 , at the same speed, within the working range of the outdoor unit of the air conditioner, the axial flow air volume of the present invention is significantly improved compared with that of the parent fan.

[0040] As shown in Figure 9 , at the same air volume, the power of the axial flow fan of the present invention does not increase compared with that of the parent fan, and is basically the same as that of the parent fan.

[0041] As shown in Figure 10 , Figure 10 is the rotational speed P-Q curve corresponding to the air volume under the same working conditions. Compared with the parent fan, the axial flow fan of the present invention has a great improvement in the compressive capacity at low and medium air volumes, and also has a partial improvement in the compressive capacity at high air volumes. It can be seen that the axial flow fan of the present invention has an improvement in the compressive capacity within the working air volume range.

[0042] In summary, the axial flow fan of the present invention has significant improvements in aspects such as reducing noise, increasing air volume, and improving compressive capacity.

[0043] As a possible implementation, the bending structure 25 includes a first end 251 that is radially close to the blade root 21 of the blade 2, and also includes a second end 252 that is radially away from the blade root 21 of the blade 2. There is a spacing L1 between the first end 251 and the second end 252 in the radial direction. The above-mentioned first end 251 and second end 252 can also be referred to as the two ends of the bending structure 25 in the radial direction of the blade 2. Optionally, the overall width of the bending structure 25 is equal. The first end 251 and the second end 252 of the bending structure can both be arc-shaped.

[0044] Since there is a radial gap 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 makes the airflow have a certain width in the radial direction of the bending structure 25, so that the airflow will not be too concentrated, thereby improving the overall air volume.

[0045] As a possible implementation, the distance between the blade root 21 and the first end 251 is denoted as L2, and the distance between the second end 252 and the outer edge 22 is denoted as L3, where L1 < |L3 - L2|.

[0046] When L1 < |L3 - L2|, this means that the influence 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 be used as a flow disturbance element to change 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 the area where the blade 2 has a higher speed, which can significantly reduce the emitted noise. 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 the manufacturing cost and also help to reduce the weight of the fan, making the device more portable.

[0047] Optionally, the bending structure 25 is provided in the middle of the blade 2 in the radial direction. Since the airflow speed in the middle of the blade 2 is usually higher than that in the edge part, the noise problem may be more serious. Therefore, this design can effectively control the noise.

[0048] As a possible implementation, L2 > L3 in the present invention. As an alternative implementation, it can also be designed as L2 < L3. In the design of the axial flow fan, according to the specific application scenario, by adjusting the distances between L1, L2, and L3, the position and size of the bending structure 25 on the blade 2 can be reasonably controlled.

[0049] As a possible implementation, the bending structure 25 extends from the leading edge 23 of the blade 2 to the trailing edge 24 of the blade 2. It can be understood that the leading edge 23 of the blade 2 refers to the part where the airflow on the blade 2 first contacts, and the trailing edge 24 of the blade 2 is the part where the airflow on the blade 2 finally leaves. The leading edge 23 and the trailing edge 24 of the blade 2 are relative to the two sides in the circumferential direction of the blade 2.

[0050] The bending structure 25 from the leading edge 23 to the trailing edge 24 of the blade 2 can better control the air flow over the entire blade 2, which helps reduce the generation of vortices, thereby improving the efficiency of the fan and reducing noise. And the entire length of the blade 2 is affected by the bending structure 25, which helps improve the overall performance of the blade 2, including improving aerodynamic efficiency, reducing aerodynamic noise, and delaying stall phenomena. In addition, this setting method also helps resist stresses and vibrations caused by centrifugal force, aerodynamic force, etc. during operation, thereby improving the stability and durability of the device.

[0051] As a possible implementation, the bending structure 25 divides the blade 2 to form 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 towards the side of the negative pressure surface 261 of the first blade 26. In other words, the part between the root 21 of the blade 2 and the first end 251 of the bending structure 25 is the first blade 26, and the part between the second end 252 of the bending structure 25 and the outer edge 22 of the blade 2 is the second blade 27.

[0052] Among them, the negative pressure surface 261 and the positive pressure surface 271 of the blade 2 are in terms of the two sides in the thickness direction of the blade 2. The negative pressure surface 261 of the blade 2 is specifically the side where the air flow generates a lower pressure when flowing over the blade 2, and the positive pressure surface 271 of the blade 2 is specifically the side where the air flow generates a higher pressure when flowing over the blade 2.

[0053] As a possible implementation, the bending structure 25 bends from the second blade 27 towards the side of the positive pressure surface 271 of the second blade 27.

[0054] The above setting method enables the bending structure 25 to bend towards different pressure surfaces of the first blade 26 and the second blade 27, which can improve the structural strength of the blade 2, reduce vibration, and enhance the stability of the device. And this design allows the air flow to flow better along the blade 2, can make better use of the positive and negative pressure surfaces of the blade 2, reduce energy loss, and thus improve the performance of the entire device. That is to say, this design helps optimize the air flow on the blade 2, improve the aerodynamic efficiency of the blade 2, reduce noise, improve the stability of the device, and improve the device performance.

[0055] As a possible implementation, each blade 2 is provided with a bending structure 25. Since each blade 2 is provided with a bending structure 25, the stiffness and vibration resistance of the blade 2 can be enhanced, the vibration of the blade 2 during operation can be reduced, and thus the stability of the device can be improved. And it is convenient for production and manufacturing, reducing production costs.

[0056] As a possible implementation, the number of bending structures 25 on each blade 2 is one.

[0057] The above-mentioned setting method can reduce the complexity of design and manufacturing, lower the manufacturing cost, better control the manufacturing process, improve the manufacturing precision and consistency, which are very important for the performance and stability of the equipment. And designing a stepped structure on each blade 2 is sufficient to change the air flow path, improve the aerodynamic efficiency of the blade 2, reduce noise, improve the stability and performance of the equipment, and can also reduce the mechanical stress of the blade 2, improving the reliability and service life of the equipment.

[0058] As a possible implementation manner, a wavy structure is provided on the trailing edge 24 of the blade 2 of the present invention. Thereby, the air flow path can be effectively changed, making the air flow smoother on the blade 2, further reducing the generation of vortices and turbulence, and then improving the aerodynamic efficiency of the entire equipment, and helping to reduce the noise caused by the vortices and turbulence generated by the air flow on the blade 2.

[0059] On the other hand, the present invention also provides an air conditioner, which includes the axial flow fan described in any of the above embodiments. Specifically, the axial flow fan can be arranged on the outdoor unit of the air conditioner. After the air conditioner has this axial flow fan, the air flow dynamic performance of the fan can be improved, so as to achieve the purpose of reducing noise while providing sufficient air volume.

[0060] It should be noted that the above embodiments are only used to illustrate the principle of the present invention and are not intended to limit the protection scope of the present invention. Without departing from the principle of the present invention, those skilled in the art can adjust the above structure so that the present invention can be applied to more specific application scenarios.

[0061] For example, as an alternative implementation manner, although the present invention is introduced with a bending structure 25 provided on each blade 2, this is not intended to limit the protection scope 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 principle of the present invention and are all within the protection scope of the present invention.

[0062] For example, as an alternative implementation manner, although the present invention is introduced with the number of bending structures 25 on each blade 2 being one, this is not intended to limit the protection scope of the present invention. For example, the number of bending structures 25 on each blade 2 can be designed as other numbers according to specific application scenarios, such as two or three, etc. These adjustments do not deviate from the principle of the present invention and are all within the protection scope of the present invention.

[0063] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope 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 further 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, wherein L1 < |L3 - L2|.

4. The axial flow fan according to claim 3, wherein 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 blade is provided with the bending structure.

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