Fan blades and axial flow fans

Abstract

This invention provides a fan blade and an axial flow fan. The fan blade is divided into sections S0 to S14 along its chord length from the blade root to the blade tip. Within the range of sections S8 to S14, the installation angle of the blade ranges from 27.0° to α to 33.0°, and the pitch chord ratio β ranges from 1.30 to β to 1.40. The fan blade and axial flow fan provided by this invention utilize sections S8 to S14 as the blade's high-efficiency working region. By reasonably limiting the pitch chord ratio β and installation angle of this high-efficiency working region, the wind resistance of the fan blade is effectively reduced, the blade's efficiency is improved, a higher airflow is ensured under low Reynolds number flow, air velocity loss is reduced, noise is lowered, and the formation of vortices at the blade tip trailing edge is reduced, further improving aerodynamic noise and enhancing user comfort.

Description

Technical Field

[0001] This invention relates to the field of air handling equipment technology, and in particular to a fan blade and an axial flow fan. Background Technology

[0002] Air conditioning products commonly use axial fan blades to drive airflow for efficient heat exchange. However, existing axial fan blades often suffer from low efficiency and high noise levels due to airflow noise vortices within the blade channel, obstructions during air intake, and stalling during air exhaust. Closed-circuit fans, for example, use closed-circuit guide rings in conjunction with axial fan blades to reduce leakage at the blade tips and suppress backflow between low and high pressure areas, effectively improving fan efficiency and reducing noise. However, large-size axial fans present a challenge in balancing high efficiency with high operating intensity. Current technologies typically increase blade thickness to enhance the operating intensity of large-size axial fans, but this makes them unsuitable for the demands of the consumer market. Furthermore, excessive blade thickness can lead to excessive airflow resistance and further reduce fan efficiency. Summary of the Invention

[0003] To address the technical problems of high power consumption and high noise in axial flow fans caused by unreasonable blade design in existing technologies, a fan blade and axial flow fan with a reasonably designed blade pitch chord ratio β and installation angle α are provided to improve the efficiency of axial flow fans, reduce fan noise, and reduce airflow resistance.

[0004] A wind turbine blade, which is divided into sections S0 to S14 along the chord length direction from the blade root to the blade tip, and within the range of sections S8 to S14, the installation angle of the blade is in the range of 27.0°≤α≤33.0°, and the pitch chord ratio β of the blade is in the range of 1.30≤β≤1.40.

[0005] Within the range of S0 to S14 of the blade, the numerical range of the blade's pitch chord ratio β is 1.16≤β≤1.37, and from the S14 section of the blade to the S10 section of the blade, the blade's pitch chord ratio β gradually increases, and from the S10 section of the blade to the S0 section of the blade, the blade's pitch chord ratio β gradually decreases.

[0006] The numerical range of the pitch chord ratio β of the blade within the S10 section of the blade is 1.37≤β≤1.40.

[0007] Within the range of section S11 to section S14 of the blade, the angle of the mounting angle is 27.5°≤α≤32.9°, and the angle of the mounting angle α gradually increases from section S14 to section S11 of the blade.

[0008] Within the range of the blade's S0 to S14 sections, the blade's installation angle α ranges from 27.5° ≤ α ≤ 33.7°. Furthermore, in the sections from S14 to S9, from S7 to S3, and from S1 to S0, the installation angle α gradually increases, while in the sections from S9 to S7 and from S3 to S1, the installation angle α gradually decreases.

[0009] In the S3 section of the blade, the installation angle α is 33.3°≤α≤33.7°.

[0010] The thickness θ of the blade is in the range of 2.4mm≤θ≤9.1mm, and the thickness of the blade gradually increases from the S14 section to the S0 section.

[0011] Within the range of section S14 to section S10 of the blade, the thickness t of the blade has a numerical range of 2.4 mm ≤ θ ≤ 4.0 mm; and / or, within the range of section S3 to section S0 of the blade, the thickness t of the blade has a numerical range of 7.0 mm ≤ θ ≤ 9.1 mm.

[0012] The blade has a twisted surface, and the blade has the greatest curvature at section S7.

[0013] The installation angle α satisfies the following formula:

[0014] α = 258.37x 6 -1363.8x 5 +1900.3x 4 -1067.7x 3 +246.5x 2 -18.106x + 33.193,

[0015] Where 0 < x < 0.71;

[0016] α = -23.8x² + 26.1x + 26.437, where 0.71 ≤ x < 1;

[0017] Where x is the ratio of the position of the blade at the cross-section to the distance from the cross-section to the root of the blade.

[0018] The pitch chord ratio β of the blade satisfies the following formula:

[0019] β = 0.0366x² + 0.2793x + 1.1555, where 0 < x < 0.71;

[0020] β = -0.28x + 1.57, where 0.71 ≤ x < 1;

[0021] Where x is the ratio of the position of the blade at the cross-section to the distance from the cross-section to the root of the blade.

[0022] The thickness θ of the blade satisfies the following formula:

[0023] θ = 8.74x² - 14.5x + 9.1, where 0 < x < 0.71;

[0024] θ = -4.2x² + 3.98x + 2.7, where 0.71 ≤ x < 1;

[0025] Where x is the ratio of the position of the blade at the cross-section to the distance from the cross-section to the root of the blade.

[0026] An axial flow fan includes the aforementioned fan blades.

[0027] The fan blades and axial flow fans provided by this invention have S8 to S14 sections as the high-efficiency working area of ​​the blades. By reasonably limiting the pitch chord ratio β and installation angle of this high-efficiency working area, the wind resistance of the fan blades is effectively reduced and the working efficiency of the blades is improved. In particular, when the pitch chord ratio β is in the range of 1.30≤β≤1.40, it can ensure a high air volume under low Reynolds number flow, reduce air velocity problems and reduce noise. When the installation angle is in the range of 27.0°≤α≤33.0°, it can reduce the formation of airflow vortices at the blade tip trailing edge, further improving the aerodynamic noise of the fan blades. Thus, it achieves the purpose of providing strong air volume, high-efficiency output air volume, improving product noise characteristics, reducing energy consumption, and effectively improving user comfort. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of a wind turbine blade provided in an embodiment of the present invention;

[0029] Figure 2 This is another structural schematic diagram of a wind turbine blade provided in an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the S0 to S14 sections of the wind turbine blades provided in an embodiment of the present invention;

[0031] Figure 4 A schematic diagram of the pitch, chord length, and installation angle of a wind turbine blade provided in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the structure of an axial flow fan blade provided in an embodiment of the present invention;

[0033] In the picture:

[0034] 1. Blade; 11. Blade root; 12. Blade tip; 2. Guide ring. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention 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 for illustrative purposes only and are not intended to limit the invention.

[0036] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0037] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate for the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0038] It should be noted that in the description of this invention, terms such as "upper," "lower," "left," "right," "inner," and "outer," indicating directional or positional relationships, are based on the directional or positional relationships shown in the accompanying drawings. These are merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0039] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection, an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0040] In axial flow fans, numerous airflow noise vortices within the blade channel, along with airflow obstruction during intake and stall during exhaust, result in low efficiency and high noise levels in existing axial flow fan blades. Current technologies employ closed guide rings in conjunction with axial flow fan blades to reduce tip leakage and suppress backflow between low and high pressure zones, effectively improving fan efficiency but also reducing overall fan efficiency. However, the performance of large-size axial flow fans is primarily influenced by the aerodynamic layout within the blade channel, aiming to achieve low intake resistance, high work capacity, and minimal exhaust stall. Therefore, this application designs the blade pitch chord ratio β based on aerodynamic theory for the three-dimensional blade structure, setting different pitch chord ratio β blade profiles for different efficiency ranges in the radial direction. This achieves a rational aerodynamic layout of the blade channel, resulting in a superior duct structure within a limited size range. Specifically, for example... Figures 1 to 4 The wind turbine blade shown is divided into sections S0 to S14 along the chord length direction of the blade 1, from the blade root 11 to the blade tip 12. Figure 3 As shown in the figure, the left edge of blade 1 is the blade tip 12, which is section S14, and the right edge is the blade root 11, which is section S0. Sections S0 to S14 are cut at equal intervals according to the chord length of blade 1. Specifically, within the range from the hub diameter to the outer diameter of the blade tip, several cylindrical sections are evenly distributed at equal intervals. The sections formed by the intersection of the cylindrical surfaces and the blade constitute sections S0 to S14 in this application. Within the range of sections S8 to S14 of blade 1, the installation angle of blade 1 is in the range of 27.0°≤α≤33.0°, and the pitch-chord ratio β of blade 1 is in the range of 1.30≤β≤1.40, where β=S / C, S refers to the pitch of blade 1, and C refers to the chord length of the corresponding section of blade 1.

[0041] Among them, the S8 to S14 sections of blade 1 are the high-efficiency working area of ​​blade 1. By reasonably limiting the pitch chord ratio β and the installation angle of this high-efficiency working area, the wind resistance of the fan blade is effectively reduced and the working efficiency of blade 1 is improved. When the pitch chord ratio β is in the range of 1.30≤β≤1.40, it can ensure a high air volume under low Reynolds number flow, reduce air velocity problems and reduce noise. When the installation angle is in the range of 27.0°≤α≤33.0°, it can reduce the formation of airflow drop vortices at the trailing edge of blade tip 12, further improve the aerodynamic noise of the fan blade, thereby achieving the purpose of providing strong air volume, high-efficiency output air volume, improving product noise characteristics, reducing energy consumption and improving user comfort.

[0042] To further define the overall shape of the blade 1, the pitch chord ratio β of the blade 1 is in the range of S0 to S14, with a value range of 1.16≤β≤1.37. Furthermore, the pitch chord ratio β of the blade 1 gradually increases from the S14 section to the S10 section, and gradually decreases from the S10 section to the S0 section. The area from section S0 to section S3 constitutes the root 11 of blade 1. The airflow velocity in this area is low, which is an inefficient work area. Therefore, the pitch chord ratio β in this area is reduced, and the installation angle is increased to ensure stable airflow. As the blade root 11 moves away from the blade 1, the work capacity of blade 1 gradually increases, and the airflow velocity increases, reaching its maximum capacity at section S10. Therefore, the pitch chord ratio β at S10 is set to the maximum, thereby increasing the relative airflow and the work capacity of blade 1 by utilizing the large pitch chord ratio β. Preferably, the value range of the pitch chord ratio β of blade 1 at section S10 is 1.37≤β≤1.40, and the pitch chord ratio β of section S10 is greater than any pitch chord ratio β of sections S0 to S9 and any pitch chord ratio β of sections S11 to S14, thereby maximizing the work capacity of blade 1, increasing the airflow of the axial fan where the fan blade is located, and reducing the energy consumption and noise of the axial fan where the fan blade is located.

[0043] Within the range of section S11 to section S14 of blade 1, the installation angle ranges from 27.5° ≤ α ≤ 32.9°, and the installation angle α gradually increases from section S14 to section S11 of blade 1. Since sections S11 to S14 constitute the blade tip 12 of blade 1, when the installation angle ranges from 27.5° ≤ α ≤ 32.9°, the formation of airflow vortices at the trailing edge of the blade tip 12 can be effectively reduced, thus improving the aerodynamic noise of the blade.

[0044] To further improve the working efficiency of the blade, within the range of section S0 to section S14 of blade 1, the installation angle α of blade 1 ranges from 27.5° ≤ α ≤ 33.7°. Furthermore, within sections S14 to S9, S7 to S3, and S1 to S0, the installation angle α of blade 1 gradually increases, while within sections S9 to S7 and S3 to S1, it gradually decreases. At this point, the surface of blade 1 exhibits a twisted shape, with a forward-sloping sweep from the leading edge of blade tip 12 to the leading edge of blade root 11. Preferably, within section S3 of blade 1, the installation angle α is 33.3° ≤ α ≤ 33.7°. That is, at the connection point between the blade root 11 and the main working part of the blade 1 at the S3 section of the blade 1, the installation angle α at this point is set to the maximum value. This can ensure the reliability of the connection between the blade root 11 and the hub in the blade 1, as well as ensure the working effect of the blade 1, change the formation of vortices in the airflow, and improve the aerodynamic noise of the blade 1.

[0045] When the installation angle α is too large, the airflow inside the axial fan will stall and there will be backflow vortex, which will reduce the overall efficiency of the axial fan. When the installation angle α is too small, the air intake resistance is too large, the work capacity at low speed is not strong, which makes it difficult to increase the air volume of the axial fan and causes loud noise at high speed.

[0046] Since blade 1 is a large-sized blade, a certain thickness is required at the connection point between blade 1 and hub to ensure reliable installation of blade 1. At the same time, the thickness at the blade tip 12 needs to be smaller to ensure low resistance and high strength axial flow fan during blade 1 rotation. Taking a blade diameter range of 550mm to 650mm as an example, the thickness t of blade 1 ranges from 2.4mm≤θ≤9.1mm, and the thickness of blade 1 gradually increases from section S14 to section S0.

[0047] Specifically, within the range from section S14 to section S10 of blade 1, the thickness t of blade 1 is in the range of 2.4mm≤θ≤4.0mm. At this time, the thickness of the blade tip section 12 of blade 1 is relatively small, which effectively reduces the wind resistance and aerodynamic noise of blade 1.

[0048] The root 11 is the stress concentration point of the blade 1. Within the range from the S3 section to the S0 section of the blade 1, the thickness t of the blade 1 is in the range of 7.0mm≤θ≤9.1mm. By increasing the thickness, the blade can be guaranteed to have high-speed operation capability and obtain a stronger air volume.

[0049] The installation angle α satisfies the following formula:

[0050] α = 258.37x 6 -1363.8x 5 +1900.3x 4 -1067.7x 3 +246.5x 2 -18.106x + 33.193,

[0051] Where 0 < x < 0.71;

[0052] α = -23.8x² + 26.1x + 26.437, where 0.71 ≤ x < 1;

[0053] Where x is the ratio of the position of the cross section on blade 1 to the distance from the cross section to the root of blade 1.

[0054] The pitch chord ratio β of blade 1 satisfies the following formula:

[0055] β = 0.0366x² + 0.2793x + 1.1555, where 0 < x < 0.71;

[0056] β = -0.28x + 1.57, where 0.71 ≤ x < 1;

[0057] Where x is the ratio of the position of the blade at the cross-section to the distance from the cross-section to the root of the blade.

[0058] The thickness θ of the blade 1 satisfies the following formula:

[0059] θ = 8.74x² - 14.5x + 9.1, where 0 < x < 0.71;

[0060] θ = -4.2x² + 3.98x + 2.7, where 0.71 ≤ x < 1;

[0061] Where x is the ratio of the position of the blade at the cross-section to the distance from the cross-section to the root of the blade.

[0062] Among them, x at the leaf root of leaf 1 is 0, and x at the leaf tip of leaf 1 is 1.

[0063] Taking a blade diameter of 600mm as an example, the specific parameters of blade 1 are shown in the table below:

[0064]

[0065]

[0066] The surface of the blade 1 is twisted, and the S7 section of the blade 1 is the intersection of the high-speed airflow region and the low-speed airflow region. Therefore, the curvature of the blade 1 is the largest at the S7 section of the blade 1, which fully ensures the balanced distribution of airflow in the blade 1 channel.

[0067] The following data is obtained by comparing the axial flow fan blade of this application with the axial flow fan blades in the prior art:

[0068]

[0069]

[0070] Existing technology - high-speed operation This application - high-speed operation 2100rpm 3000rpm

[0071] As can be seen from the above data results, the axial flow fan of this application has relatively lower noise at any air volume compared with the axial flow fan of the prior art, thus achieving the purpose of reducing noise compared with the prior art; and under the premise of achieving any same air volume, the power of this application is less than that of the prior art, effectively reducing the energy consumption of the axial flow fan.

[0072] like Figure 5 As shown, an axial flow fan includes the aforementioned fan blades.

[0073] In one implementation, the axial flow fan has four fan blades, and the four fan blades are evenly distributed.

[0074] The axial flow fan is also equipped with a guide ring 2, which further reduces blade tip leakage and improves fan efficiency.

[0075] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A wind turbine blade, characterized in that: Along the chord length direction of the blade (1), from the root (11) to the tip (12), the blade (1) is divided into sections S0 to S14. Within the range of sections S8 to S14 of the blade (1), the installation angle of the blade (1) is 27.0°≤α≤33.0°. Within the range of sections S0 to S14 of the blade (1), the pitch-chord ratio β of the blade (1) is 1.16≤β≤1.

40. From section S14 to section S10 of the blade (1), the pitch-chord ratio β of the blade (1) gradually increases. From section S10 to section S0 of the blade (1), the pitch-chord ratio β of the blade (1) gradually decreases.

2. The wind turbine blade according to claim 1, characterized in that: The numerical range of the pitch chord ratio β of the blade (1) within the S10 section of the blade (1) is 1.37≤β≤1.

40.

3. The wind turbine blade according to claim 1, characterized in that: Within the range of section S11 to section S14 of the blade (1), the angle range of the mounting angle is 27.5°≤α≤32.9°, and the angle α of the mounting angle gradually increases from section S14 to section S11 of the blade (1).

4. The wind turbine blade according to claim 1 or 3, characterized in that: Within the range of section S0 to section S14 of the blade (1), the installation angle α of the blade (1) ranges from 27.5° to α to 33.7°. In the range of section S14 to section S9 of the blade (1), section S7 to section S3 of the blade (1), and section S1 to section S0 of the blade (1), the installation angle α of the blade (1) gradually increases. In the range of section S9 to section S7 of the blade (1), and section S3 to section S1 of the blade (1), the installation angle α of the blade (1) gradually decreases.

5. The wind turbine blade according to claim 4, characterized in that: In the S3 section of the blade (1), the angle of the mounting angle α is 33.3°≤α≤33.7°.

6. The wind turbine blade according to claim 1, characterized in that: The thickness t of the blade (1) ranges from 2.4 mm ≤ θ ≤ 9.1 mm, and the thickness of the blade (1) gradually increases from the S14 section to the S0 section.

7. The wind turbine blade according to claim 6, characterized in that: Within the range of section S14 to section S10 of the blade (1), the thickness t of the blade (1) is in the range of 2.4 mm ≤ θ ≤ 4.0 mm; and / or, within the range of section S3 to section S0 of the blade (1), the thickness t of the blade (1) is in the range of 7.0 mm ≤ θ ≤ 9.1 mm.

8. The wind turbine blade according to claim 1, characterized in that: The surface of the blade (1) is twisted, and the curvature of the blade (1) is greatest at the S7 section of the blade (1).

9. The wind turbine blade according to claim 1, characterized in that: The installation angle α satisfies the following formula: α=258.37x 6 -1363.8x 5 +1900.3x 4 -1067.7x 3 +246.5x 2 -18.106x+33.193, where 0<x<0.71; α = -23.8x 2 +26.1x+26.437, where 0.71≤x<1; Where x is the ratio of the position of the cross section on the blade (1) to the distance from the cross section to the root of the blade (1).

10. The wind turbine blade according to claim 1, characterized in that: The pitch chord ratio β of the blade (1) satisfies the following formula: β=0.0366x 2 +0.2793x+1.1555, where 0<x<0.71; β = -0.28x + 1.57, where 0.71 ≤ x < 1; Where x is the ratio of the position of the cross section on the blade (1) to the distance from the cross section to the root of the blade (1).

11. The wind turbine blade according to claim 7, characterized in that: The thickness θ of the blade (1) satisfies the following formula: θ = 8.74x² - 14.5x + 9.1, where 0 < x < 0.71; θ = -4.2x² + 3.98x + 2.7, where 0.71 ≤ x < 1; Where x is the ratio of the position of the cross section on the blade (1) to the distance from the cross section to the root of the blade (1).

12. An axial flow fan, characterized in that: Includes the wind turbine blades according to any one of claims 1 to 11.

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