Axial flow fan blade, axial flow fan and air conditioner

Abstract

The invention provides an axial flow fan blade, an axial flow fan and an air conditioner, the axial flow fan blade comprises a hub and a plurality of blades located on the outer ring wall face of the hub, the blade mounting angle of each blade is beta, the forward bending angle is theta, the blade lattice consistency of the axial flow fan blade is tau, beta =-10.667 r < 3 > + 24r < 2 >-25.733 r + 32.4, theta = 2.999 r < 3 > + 31.93 r < 2 >-13.567 r, tau =-0.7529 r < 3 > + 2.0348 r < 2 >-1.6831 r + 1.2, r is the percentage blade height of each blade, r belongs to [0, 1], and the thickness of the blade lattice of each blade is [0, 1]. The units of beta and theta are both degrees, and tau is dimensionless. According to the axial flow fan blade, under the high static pressure working condition, flowing of air in all element levels of the fan blade is greatly improved, the forward bending angle is controlled, secondary flow and radial pressure distribution in the blade height direction are improved, blade airflow separation is reduced, the impact loss of the front edge of the fan blade is reduced, and the wake form of the tail edge of the blade is improved; the pneumatic performance of the fan blade is improved, and noise is reduced.

Description

Technical Field

[0001] This invention belongs to the field of air conditioning design technology, specifically relating to an axial flow fan blade, an axial flow fan, and an air conditioner. Background Technology

[0002] Axial flow fans are characterized by large flow rates, low static pressure, and compact structure, and are widely used in industries such as animal husbandry, fire protection, and automobiles. However, as users and manufacturers increasingly prioritize quality, noise issues have become more prominent. Reducing fan speed is an effective way to reduce noise; however, under high static pressure conditions, reducing the speed may lead to excessively low blade specific speed, severe airflow separation, and a sharp decline in fan performance. Summary of the Invention

[0003] Therefore, the present invention provides an axial flow fan blade, an axial flow fan and an air conditioner, which can overcome the shortcomings of related technologies where axial flow fans reduce fan speed to lower noise levels, resulting in severe airflow separation of the fan blades and a sharp decline in fan performance under high static pressure conditions.

[0004] To address the aforementioned problems, this invention provides an axial flow fan blade, comprising a hub and a plurality of blades disposed on the outer annular wall of the hub. Each blade has an installation angle of β and a forward bend angle of θ. The blade cascade density of the axial flow fan blade is τ, where β = -10.667r. 3 + 24r 2 - 25.733r + 32.4, θ = 2.999r 3 + 31.93r 2 -13.567r, τ= -0.7529r 3 + 2.0348r 2 - 1.6831r + 1.2, where r is the percentage leaf height of each leaf, r∈[0,1], β and θ are in °, and τ is dimensionless.

[0005] In some embodiments, the relative thickness of each elementary-level blade is... , ∈[0.88%,7.7%].

[0006] In some implementations... =c max / b, where b is the leaf chord length, c max The diameter is the maximum inscribed circle of the blade shape, and the maximum thickness of the blade shape is located at 0.2 to 0.3 times the chord length, starting from the leading edge of the blade shape.

[0007] In some embodiments, the relative camber of each elementary-level airfoil of each blade is... , ∈[2.9%,8.8%].

[0008] In some implementations... =f max / b, where f max The maximum curvature of the blade is defined as the maximum curvature of the blade, which is located at 0.45 to 0.55 times the chord length, starting from the leading edge of the blade.

[0009] In some embodiments, the outer diameter of the hub is R1, the outer diameter of the fan blade is R2, and the ratio of R1 to R2 is between 0.25 and 0.3.

[0010] In some embodiments, the trailing edge of each blade has a plurality of serrated grooves spaced apart along its stacking line.

[0011] In some implementations, the number of blades is odd.

[0012] The present invention also provides an axial flow fan, including the axial flow fan blades described above.

[0013] The present invention also provides an air conditioner including the axial flow fan described above.

[0014] The axial flow fan blade, axial flow fan, and air conditioner provided by this invention have the following beneficial effects:

[0015] By optimizing the blade installation angle β, blade cascade consistency τ, and forward bend angle θ of each blade, the airflow at each basic level of the axial flow fan under high static pressure conditions is greatly improved. The blade sweep structure feature, namely the aforementioned forward bend angle control, improves the secondary flow and radial pressure distribution along the blade height, reduces airflow separation, reduces blade leading edge impact loss, improves the blade trailing edge wake morphology, improves the aerodynamic performance of the fan, and reduces noise. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. The drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0017] Figure 1 This is a three-dimensional structural schematic diagram of the axial flow fan blade according to an embodiment of the present invention;

[0018] Figure 2 yes Figure 1 The figure shows the axial projection of a blade, with the cross-sectional positions at different blade heights.

[0019] Figure 3 Figure 2 The basic unit level (airfoil) at each leaf height is formed by cutting the blade with a cross-section at different leaf heights.

[0020] Figure 4 yes Figure 1 A schematic diagram of the overlapping line parameters of the blades in the diagram;

[0021] Figure 5 yes Figure 1 The illustration shows the leaf shape and cascade parameters of the blades.

[0022] Figure 6 This is a three-dimensional structural diagram of the axial flow fan blade in the existing technology (i.e., the original solution);

[0023] Figure 7 This is a comparison of the air volume-static pressure curves between the technical solution of this invention (new solution) and the existing technology (original solution);

[0024] Figure 8 This is a comparison of the air volume-static pressure efficiency curves of the technical solution of this invention (new solution) and the existing technology (original solution);

[0025] Figure 9 This is a simulation diagram of airflow on the blade surface of the technical solution of this invention;

[0026] Figure 10 This is a simulation diagram of airflow on the blade surface in existing technology;

[0027] Figure 11 This is a simulation diagram of the streamline of the wind turbine blades in the technical solution of this invention;

[0028] Figure 12 This is a simulation diagram of the streamline of a wind turbine blade in existing technology;

[0029] Figure 13 This is a simulation diagram of the static pressure distribution of the wind turbine blades according to the technical solution of this invention;

[0030] Figure 14 This is a simulation diagram of static pressure distribution on wind turbine blades in existing technology.

[0031] The attached figures are labeled as follows:

[0032] 1. Hub; 2. Blade; 21. Serrated groove; m. Accumulation line; o. Leading edge of blade; p. Trailing edge of blade. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0035] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90° or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0036] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0037] See also Figures 1 to 14 As shown, according to an embodiment of the present invention, an axial flow fan blade is provided, including a hub 1 and a plurality of blades 2 on the outer annular wall of the hub 1. Specifically, each blade 2 is evenly spaced around the rotation axis of the hub 1, such as... Figure 2 , 3As shown, the cross-section of blade 2 at a certain blade height along the radial direction of the blade (i.e., the radial direction of the hub 1) is called the elementary stage. 0% blade height and 100% blade height are located at the blade root and blade tip, respectively. See [reference needed]. Figure 2 As shown, the blade 2 of the present invention is formed by the elementary levels at 0%, 25%, 50%, 75%, and 100% along the stacking line (e.g., ...). Figure 4 (As shown in the figure) the superposition generation, see details. Figure 4 As shown, the line connecting the midpoints of the airfoil centerlines (the airfoil centerline is the line connecting the centers of the inscribed circles of the airfoil) of each elementary level is taken as the accumulation line. The forward bending angle θ is defined as the angle between a point on the accumulation line and the line connecting the center of rotation and the line connecting the root of the accumulation line and the center of rotation.

[0038] Element-level airfoil and cascade parameters as follows Figure 5 As shown, the blade installation angle β is defined as the acute angle between the blade chord line b (the blade chord line b is the line connecting the intersection of the blade centerline and the leading and trailing edges of the blade) and the cascade line, with the maximum camber f being the maximum camber. max Defined as the distance between the highest point of the blade centerline and the blade chord line, with maximum thickness c. max Defined as the diameter of the largest inscribed circle of the airfoil, the cascade pitch t is the circumferential distance between corresponding points of adjacent airfoils, the cascade consistency τ = b / t, β = -10.667r 3 + 24r 2 -25.733r +32.4, θ = 2.999r 3 + 31.93r 2 -13.567r, τ = -0.7529r 3 + 2.0348r 2 - 1.6831r + 1.2, where r is the percentage leaf height of each of the aforementioned leaves 2, r∈[0,1], β and θ are in °, τ is dimensionless, and the aforementioned r=1 means r=100%, and r=0 means r=0%.

[0039] In this technical solution, by optimizing the design of the blade installation angle β, blade cascade consistency τ, and forward bend angle θ of each blade 2, the airflow in each basic unit of the axial flow fan blade is greatly improved under high static pressure conditions. The blade sweep structure feature, namely the aforementioned forward bend angle control, improves the secondary flow and radial pressure distribution along the blade height direction, reduces airflow separation, reduces blade leading edge impact loss, improves the blade trailing edge wake morphology, improves the aerodynamic performance of the fan blade, and reduces noise.

[0040] In some embodiments, the relative thickness of each elementary-level blade of each blade 2 is , ∈[0.88%, 7.7%], =c max / b, where b is the chord length of the leaf shape.

[0041] In this technical solution, the relative thickness of blade 2 is limited, so that the relative thickness of blade 2 is larger at the blade root and smaller at the blade tip. This prevents the blade from being too weak and having low anti-stall capability due to too small a relative thickness, and from being too weak and having low aerodynamic efficiency due to too large a relative thickness. It balances the blade's aerodynamic performance with airflow stability and the blade's high strength.

[0042] The maximum thickness of the blade (i.e., the diameter of the maximum inscribed circle of the blade) is located at 0.2 to 0.3 times the chord length, starting from the leading edge o of the blade.

[0043] In this technical solution, the position of the maximum thickness of the blade is optimized to prevent the maximum thickness position from being too far forward, which would reduce the efficiency of the blade, or too far backward, which would increase noise.

[0044] In some embodiments, the relative camber of each elementary-level airfoil of each blade 2 is... , ∈[2.9%, 8.8%], specifically, =f max / b, where f max The maximum curvature of the blade is defined as the maximum curvature of the blade, which is located at 0.45 to 0.55 times the chord length, starting from the leading edge o of the blade.

[0045] In this technical solution, the relative curvature of each elementary stage blade of each blade 2 is limited, and the position of the maximum curvature is limited, so that the maximum curvature position of the blade 2 is set in the center, which prevents the airflow velocity at the blade tip from being too high and the curvature from being too large, which can easily cause flow separation and increase noise. The velocity at the blade root is low, and the use of a larger curvature can improve the work capacity in the low-speed region, so that the efficiency and anti-stall performance of the blade are at a better level.

[0046] In some embodiments, the outer diameter of the hub 1 is R1, the outer diameter of the fan blade 2 is R2, and R1 / R2 is between 0.25 and 0.3. In a specific embodiment, R1 = 250 mm and R2 = 898 mm.

[0047] In this technical solution, the hub ratio is optimized and limited to prevent the blade strength from decreasing due to a smaller hub ratio, and the air volume from decreasing due to a larger hub ratio.

[0048] It is understandable that the front end of blade 2 along the direction of rotation is called the leading edge o, and the rear end along the direction of rotation is called the trailing edge p.

[0049] In some embodiments, the trailing edge b of each blade 2 has a plurality of serrated grooves 21 spaced apart along its stacking line m. The serrated grooves 21 on the trailing edge b can disrupt the vortex generated at the trailing edge and further reduce the noise of the blade operation.

[0050] Considering that the number of pole pairs of a motor is generally even, in order to avoid resonance, in some embodiments, the number of blades 2 is determined to be odd. The optimal number of blades in this invention is 5.

[0051] Table 1: Performance parameters of wind turbine blades in existing technologies

[0052]

[0053] Table 2: Wind turbine performance parameters in the technical solution of this invention

[0054]

[0055] For comparison, please refer to Tables 1 and 2. Figure 7 , Figure 8 As shown, it can be clearly seen that the fan blade of the present invention has higher static pressure efficiency and static pressure than the fan blades in the prior art under the same air volume conditions, and the air volume is greater than that of the fan blades in the prior art under the same static pressure conditions.

[0056] See comparison Figure 9 and Figure 10 As shown, it can be clearly seen that the airflow on the surface of the wind turbine blades in the present invention flows circumferentially around the rotation axis of the hub 1, with a small radial component, while the airflow on the surface of the wind turbine blades in the prior art has a larger radial outward flow component.

[0057] See comparison Figure 11 and Figure 12 As shown, it can be clearly seen that the wind turbine blades of the present invention significantly reduce the impact loss at the leading edge of the wind turbine blades and improve the trailing edge morphology of the blades.

[0058] See comparison Figure 13 and Figure 14 As shown, it can be clearly understood that the pressure gradient in the negative pressure region at the front edge of the blade suction face of the technical solution of the present invention is reduced, thereby reducing the driving force of the airflow moving radially and thus suppressing the occurrence of blade tip leakage.

[0059] In summary, this invention significantly improves airflow at each basic level of the wind turbine blade under high static pressure conditions by optimizing blade installation angle, cascade density, and forward bend angle. The blade sweep structure controls and improves secondary flow and radial pressure distribution along the blade height, reduces leading-edge impact loss, improves the trailing-edge wake morphology, enhances the aerodynamic performance of the wind turbine blade, and reduces noise.

[0060] According to an embodiment of the present invention, an axial flow fan is also provided, including the axial flow fan blades described above.

[0061] An embodiment of the present invention also provides an air conditioner including the axial flow fan described above.

[0062] It will be readily understood by those skilled in the art that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. An axial flow fan blade, characterized in that, The axial flow fan includes a hub (1) and multiple blades (2) on the outer ring wall of the hub (1). Each blade (2) has a blade mounting angle of β and a forward bending angle of θ. The blade density of the axial flow fan is τ, and β = -10.667r. 3 + 24r 2 - 25.733r + 32.4, θ = 2.999r 3 + 31.93r 2 -13.567r, τ = -0.7529r 3 + 2.0348r 2 - 1.6831r + 1.2, where r is the percentage leaf height of each of the aforementioned leaves (2), r∈[0,1], β and θ are in °, and τ is dimensionless.

2. The axial flow fan blade according to claim 1, characterized in that, The relative thickness of each elementary-level blade of each blade (2) is as follows: , ∈[0.88%,7.7%].

3. The axial flow fan blade according to claim 2, characterized in that, =c max / b, where b is the leaf chord length, c max The diameter is the maximum inscribed circle of the blade shape, and the maximum thickness of the blade shape is located at 0.2 to 0.3 times the chord length starting from the leading edge (o) of the blade shape.

4. The axial flow fan blade according to claim 3, characterized in that, The relative curvature of each elementary level blade (2) is as follows: , ∈[2.9%,8.8%].

5. The axial flow fan blade according to claim 4, characterized in that, =f max / b, where f max The maximum curvature of the blade is defined as the maximum curvature of the blade located at 0.45 to 0.55 times the chord length, starting from the leading edge (o) of the blade.

6. The axial flow fan blade according to any one of claims 1 to 5, characterized in that, The outer diameter of the hub (1) is R1, and the outer diameter of the fan blade (2) is R2, with R1 / R2 being between 0.25 and 0.

3.

7. The axial flow fan blade according to any one of claims 1 to 5, characterized in that, Each blade (2) has a plurality of serrated grooves (21) spaced along its stacking line (m) at the trailing edge (p).

8. The axial flow fan blade according to any one of claims 1 to 5, characterized in that, The number of blades (2) is odd.

9. An axial flow fan, characterized in that, Includes the axial flow fan blades according to any one of claims 1 to 8.

10. An air conditioner, characterized in that, Including the axial flow fan as described in claim 9.

Images