Axial flow fan blade and fan having the same

Abstract

The present invention provides an axial flow fan blade and a fan having the same. The axial flow fan blade includes a hub and a blade. The blade has a leading edge and a trailing edge arranged oppositely along the direction of rotation. A reference variable cylinder S is provided. The cylinder S is arranged concentrically with the hub. The midpoint of the cross section of the intersection of the cylinder S and the blade is a, the line connecting the midpoint of the blade root and the center of the hub is L2, the line connecting point a and the center of the hub is L3, and the angle between L2 and L3 is the net bending angle A1 of the blade. The maximum radius of the blade is R, the radius of the cylinder S is r, the ratio of r / R is between 0.4 and 0.95, and as the ratio of r / R gradually increases, the angle value of A1 also gradually increases, and the angle value of A1 is between 5° and 43°. The technical solution provided by the present application can solve the problem of low air supply efficiency of blades in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of axial flow fan blades, and in particular to an axial flow fan blade and a fan having the same. Background Art

[0002] At present, during the operation of existing axial flow blades, the mainstream velocity in the boundary layer is low, and the centrifugal force of the blade is greater than the radial pressure gradient. This causes the low-energy fluid in the boundary layer to migrate radially outward and accumulate near the blade tip, thereby increasing the blade tip loss and blade tip stall, affecting the air supply efficiency. Summary of the Invention

[0003] The present invention provides an axial flow fan blade and a fan having the same, so as to solve the problem of low air supply efficiency of the blades in the prior art.

[0004] According to one aspect of the present invention, an axial flow fan blade is provided, which includes a hub and blades, wherein the blades have leading edges and trailing edges relatively arranged along the direction of rotation, and a reference variable cylinder S is provided, and the cylinder S is concentrically arranged with the hub; the midpoint of the cross section cut by the intersection of the cylinder S and the blade is a, the line connecting the midpoint of the blade root and the center of the hub is L2, the line connecting point a and the center of the hub is L3, and the angle between L2 and L3 is the net bending angle A1 of the blade; wherein the maximum radius of the blade is R, the radius of the cylinder S is r, the ratio of r / R is between 0.4 and 0.95, and when the ratio of r / R gradually increases, the angle value of A1 also gradually increases, and the angle value of A1 is between 5° and 43°.

[0005] Furthermore, the intersection point of the cylinder S and the leading edge of the blade is C, the line connecting C and the center of the hub is L4, the tangent of the leading edge of the blade at point C is L5, and the angle between L5 and L4 is the leading edge guide bending angle A2. When the ratio of r / R gradually increases, the angle value of A2 also gradually increases, and the angle value of A2 is between 29° and 59°.

[0006] Furthermore, the intersection point of the cylinder S and the trailing edge of the blade is D, the line connecting D and the center of the hub is L6, the tangent of the trailing edge of the blade at point D is L7, and the angle between L7 and L6 is the trailing edge guide bending angle A3. When the ratio of r / R gradually increases, the angle value of A3 also gradually increases, and the angle value of A3 is between 31° and 42°.

[0007] Furthermore, the angle between the chord length of the cross section obtained by the intersection of the cylinder S and the blade and the rotation plane of the blade is the blade installation angle Q, wherein when the ratio of r / R gradually increases, the angle value of Q gradually decreases, and the angle value of Q is between 32.5° and 28°.

[0008] Furthermore, the chord length of the cross section formed by the intersection of the cylinder S and the blade is b, wherein when the ratio r / R gradually increases, the ratio b / R also gradually increases, and the ratio b / R is between 0.5 and 1.5.

[0009] Furthermore, an included angle α is set between the leading edge of the blade and the blade top, and the angle value of α is between 40° and 50°.

[0010] Furthermore, the maximum diameter of the blade is d1, the diameter of the hub is d2, and the ratio of d2 / d1 is between 0.25 and 0.35.

[0011] Furthermore, the axial flow fan blade includes a plurality of blades, and the number of the plurality of blades is an odd number.

[0012] According to another aspect of the present invention, a fan is provided, comprising the axial flow blades provided above.

[0013] By applying the technical solution of the present invention, when designing the blade, a reference variable cylinder S is provided, and the cylinder S is concentrically arranged with the hub, wherein the midpoint of the cross section of the intersection of the cylinder S and the blade is a, the line connecting the midpoint of the root of the blade and the center of the hub is L2, the line connecting point a and the center of the hub is L3, and the angle between L2 and L3 is the net bending angle A1 of the blade. When the ratio of r / R is between 0.4 and 0.95, the angle value of A1 is correspondingly between 5° and 43°. With such a setting, the degree of bending of the blade tip can be limited, and the centrifugal force of the fluid in the blade boundary layer can be reduced by this limitation, which can effectively suppress the blade tip stall, thereby reducing the energy loss at the blade tip and improving the blade air supply efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0015] Figure 1 A schematic structural diagram of an axial flow fan blade according to an embodiment of the present invention is shown;

[0016] Figure 2 The cross section obtained by intersecting a blade and a cylinder S in an axial flow fan blade provided in an embodiment of the present invention is shown;

[0017] Figure 3 Shown Figure 1 Schematic diagram of the structure of the middle blade;

[0018] Figure 4 shows another structural schematic diagram of an axial flow fan blade provided according to an embodiment of the present invention;

[0019] Figure 5 A left side view of an axial flow fan blade provided according to an embodiment of the present invention is shown.

[0020] The above drawings include the following reference numerals:

[0021] 10. Hub; 20. Blade; 21. Leading edge; 22. Trailing edge; 23. Blade tip; 24. Blade root; 25. Suction side; 26. Pressure side. DETAILED DESCRIPTION

[0022] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] like Figures 1 to 5 As shown, the present application provides an axial flow fan blade, which includes a hub 10 and a blade 20, and the blade 20 has a leading edge 21 and a trailing edge 22 that are relatively arranged along the rotation direction. When designing the size of the axial flow fan blade, it is necessary to introduce a reference variable cylinder S, wherein the cylinder S is concentrically arranged with the hub 10, and the center of the hub 10 is O. The cylinder S is used to intersect with the blade 20 to obtain the corresponding parameter value. Specifically, the midpoint of the cross-section where the cylinder S intersects the blade 20 is a, the line connecting the midpoint of the blade tip 23 and a is L1, the line connecting the midpoint of the blade root 24 and the center of the hub 10 is L2, and the line connecting point a and the center of the hub 10 is the line connecting the intersection of L1 and the cylinder S and the center of the hub 10, which is L3. The angle between L2 and L3 is the net bending angle A1 of the blade, where the maximum radius of the blade 20 is R, the radius of the cylinder S is r, and when the ratio of r / R is between 0.4 and 0.95, the angle value of A1 is correspondingly set between 5° and 43°.

[0024] With the axial flow fan blade provided by the present application, when designing the blade 20, a reference variable cylinder S is provided, and the cylinder S is concentrically arranged with the hub 10, wherein the midpoint of the cross section of the intersection of the cylinder S and the blade 20 is a, the line connecting the midpoint of the blade root 24 and the center of the hub 10 is L2, the line connecting point a and the center of the hub 10 is L3, and the angle between L2 and L3 is the net bending angle A1 of the blade. When the ratio of r / R is between 0.4 and 0.95, the angle value of A1 is correspondingly between 5° and 43°. With such a setting, the degree of bending of the blade tip 23 can be limited, and the centrifugal force of the fluid in the blade boundary layer can be reduced through this limitation, which can effectively suppress the blade tip stall, thereby reducing the energy loss at the blade tip and improving the blade air supply efficiency.

[0025] Specifically, in this embodiment, when the values ​​of r / R are 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9 and 0.95, the corresponding values ​​of the net bending angle A1 of the blade are 5°, 9°, 13°, 15°, 18°, 22°, 25°, 28°, 32°, 35°, 39° and 43°.

[0026] Furthermore, the intersection point of the cylinder S and the leading edge 21 of the blade is set to C, the line connecting C and the center O of the hub 10 is L4, the tangent line of the leading edge 21 of the blade at point C is L5, and the angle between L5 and L4 is the leading edge guide curvature angle A2, wherein the angle value of A2 is set between 29° and 59°. By limiting the angle A2, the degree of curvature of the blade leading edge can be limited. The above design can increase the leading edge curvature angle, gradually increasing the curvature of the leading edge from the blade root 24 to the blade tip 23. This setting can eliminate the backflow problem existing at the impeller leading edge 21, absorb the low-energy fluid in the end wall area into the high-energy mainstream of the blade, reduce the accumulation of low-energy fluid at the end, and thus reduce flow loss and flow blockage. Furthermore, the above-described design reduces the impact of the casing and hub endwalls on the gas flow within the flow channel, suppresses the accumulation of low-energy fluid, and accelerates the decay rate of the blade 20 wake. The secondary flow characteristic, in which the low-energy fluid near the suction surface 25 of the blade endwall is carried downstream by the mainstream, significantly improves the internal flow state within the blade 20, thereby suppressing the shedding of vortices on the blade 20 surface, reducing the broadband noise of the blade 20, and improving the sound quality. Furthermore, experimental simulations have shown that increasing the sweep of the blade leading edge 21 significantly increases the static pressure values ​​on the suction surface 25 and pressure surface 26 at the blade leading edge 21, improving the distribution of the pressure gradient on the blade surface, thereby increasing the effective work area on the blade surface and improving blade performance.

[0027] In this embodiment, when the values ​​of r / R are 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9 and 0.95, the corresponding values ​​of the leading edge guide bending angle A2 are 29°, 29°, 30°, 32°, 35°, 38°, 42°, 46°, 50°, 53°, 56° and 59°.

[0028] Specifically, the intersection point of the cylinder S and the trailing edge 22 of the blade is set to D, the line connecting D and the center of the hub 10 is L6, the tangent line of the trailing edge 22 of the blade at point D is set to L7, the angle between L7 and L6 is the trailing edge guide bending angle A3, and the angle value of A3 is set between 31° and 42°. The above design can limit the degree of sweep of the trailing edge 22 of the blade, so that the sweep angle of the trailing edge 22 of the blade gradually increases from the blade root 24 to the blade tip 23. When the turbulent boundary of the blade surface passes through the trailing edge of the blade, local pulsating forces are generated, and the Karman vortex street at the trailing edge of the blade also generates local pulsating forces with narrower frequency characteristics. Due to the existence of these pulsating forces, vortex shedding occurs on the blade, thereby generating blade noise. By improving and limiting the trailing edge guide bending angle A3 in this application, vortex detachment at the trailing edge 22 of the blade can be effectively suppressed, thereby reducing blade noise.

[0029] In this embodiment, when the values ​​of r / R are 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9 and 0.95, the corresponding values ​​of the trailing edge guide bending angle A3 are 31°, 31°, 31°, 32°, 33°, 35°, 36°, 37°, 39°, 40°, 41° and 42°.

[0030] like Figure 2 As shown, the angle between the chord length of the cross section formed by the intersection of the cylinder S and the blade 20 and the rotation plane of the blade 20 is the blade installation angle Q, where the angle value of Q is set between 32.5° and 28°. This design can define the blade installation angle Q at different cross-sectional locations of the blade 20, such that the installation angle gradually decreases from the blade root 24 to the blade tip 23.

[0031] If the blade installation angle is too large, the space for air fluid to flow through the impeller will be reduced, the inlet resistance will be increased, and the flow of fluid will be hindered. In addition, a large installation angle will increase the load on the blade, thereby affecting the pressure distribution on the blade surface, increasing pressure pulsation, and causing the load noise of the blade to increase. If the blade installation angle is too small, the lift of the blade will decrease, and the blade's ability to work axially on the air fluid will be weakened, the airflow energy loss will increase, and the efficiency of the fan will be reduced. Through the design of this application, the blade installation angle can be set reasonably, so that the air fluid at the impeller inlet can smoothly enter the impeller area, thereby improving the efficiency of the entire machine.

[0032] In this embodiment, when the values ​​of r / R are 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, and 0.95, the corresponding values ​​of the blade installation angle Q are 32.45°, 32.42°, 32.33°, 32.25°, 32.08°, 31.94°, 31.68°, 31.25°, 30.59°, 29.92°, 29.84°, and 28.17°. In this embodiment, the blade installation angle at the blade root 24 is set larger to effectively ensure blade strength and prevent excessive blade load. The blade installation angle at the blade tip 23 is gradually reduced to effectively reduce the overall blade load, thereby reducing the pressure on the motor.

[0033] Among them, the chord length of the cross section obtained by the intersection of the cylinder S and the blade 20 is set to b, which is the line connecting the two end points of the cross section. When the ratio of r / R gradually increases, the ratio of b / R also gradually increases, and the ratio of b / R is set between 0.5 and 1.5. Since the main source of noise generated by the fan is the airflow pulsation force acting on the blade, the airflow pulsation force will cause vortices on the blade surface and the separation of the vortices, thereby generating noise. Through the above design, the chord length of the blade in different cross sections can be limited, so that the chord length of the blade gradually increases from the blade root 24 to the blade top 23. Such a design can effectively suppress and reduce the formation and separation of the blade surface vortex, thereby achieving the purpose of noise reduction. In addition, this technical solution can reduce the pressure gradient between the blade root 24 and the blade top 23, thereby achieving the purpose of reducing the low power consumption area of ​​the blade.

[0034] In this embodiment, when the values ​​of r / R are 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9 and 0.95, the corresponding values ​​of b / R are 0.548, 0.685, 0.755, 0.867, 0.899, 0.972, 1.054, 1.142, 1.204, 1.288, 1.386 and 1.472.

[0035] Specifically, an angle α is set between the leading edge 21 of the blade and the blade tip 23, with the angle α being set between 40° and 50°. This design effectively reduces the generation of tip vortices and leading edge separation vortices, thereby achieving the purpose of reducing aerodynamic noise. Specifically, the tangent line of the leading edge 21 of the blade at the intersection of the leading edge and the blade tip is L8, and the tangent line of the blade tip 23 at the intersection of the leading edge and the blade tip is L9. The angle between L8 and L9 is set to α.

[0036] like Figure 4 As shown, the maximum diameter of blade 20 is set to d1, the diameter of hub 10 is set to d2, and the ratio d2 / d1 is set between 0.25 and 0.35. This technical solution limits the size of hub 10. A larger ratio reduces fan efficiency and overall aerodynamic performance. Conversely, a smaller ratio can cause airflow separation at the blade root 24, and even cause the fan to stall. By limiting this ratio, it can be controlled within a reasonable range, ensuring fan efficiency and preventing airflow separation.

[0037] Specifically, the axial flow fan blade includes a plurality of blades 20, and the number of blades 20 is set to an odd number. In the present embodiment, the number of blades 20 is 3, and of course an odd number of blades such as 5, 7, or 9 can also be adjusted to be selected. A smaller number of blades will reduce the overall working area of ​​the fan blade, thereby affecting the air volume of the fan blade; a larger number of blades will increase the area ratio of the blade at the cross-flow surface, reduce the fluid flow area, and increase the overall load of the fan blade, thereby increasing the cost of the motor. Therefore, a reasonable number of blades should be selected according to the actual working conditions used. The axial flow fan blade is set to an odd number of blades to avoid the fan blade having a symmetrical structure and reduce the possibility of fatigue fracture and vibration of the fan blade during operation.

[0038] The comparison of operating parameters of the axial flow fan blades provided by this application and the fan blades of the prior art is shown in the following table:

[0039] plan Outlet wind speed (m / s) Air supply distance (m) <![CDATA[Air volume (m 3 / min)]]> Energy efficiency Noise (dB) Existing technology fan blade 5.3 8.8 15.18 1.03 46.3 This application fan blade 5.8 11 17.21 1.26 44.3

[0040] It can be seen from the above table that at the same speed, the performance and efficiency of the fan blades designed in this application are improved compared with the existing technology, and the wind gathering effect is significantly improved. In addition, the noise peak of the fan blades during operation is significantly reduced.

[0041] The technical solution provided in this application can improve the problem of air divergence caused by traditional fan blades, enhance the wind gathering effect of axial fan blades, increase the air volume of blades, and increase the wind speed and air supply distance of axial and circumferential air supply outlets. In addition, the fan blades of this application can also improve energy efficiency and reduce motor costs.

[0042] Yet another embodiment of the present application provides a fan, which includes the axial flow blades provided in the above embodiment.

[0043] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0044] Unless otherwise specifically stated, the relative arrangement of the parts and steps, the numerical expressions and the numerical values ​​set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values ​​should be interpreted as being merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0045] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0046] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0047] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0048] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. An axial flow fan blade, characterized in that: The axial flow fan blade comprises a hub (10) and a blade (20), wherein the blade (20) has a leading edge (21) and a trailing edge (22) arranged opposite to each other in the direction of rotation, and is provided with a reference variable cylinder S, wherein the cylinder S is arranged concentrically with the hub (10); The midpoint of the cross section of the cylinder S intersecting the blade (20) is a, the line connecting the midpoint of the blade root (24) and the center of the hub (10) is L2, the line connecting point a and the center of the hub (10) is L3, and the angle between L2 and L3 is the net bending angle A1 of the blade; The maximum radius of the blade (20) is R, the radius of the cylinder S is r, and the ratio of r / R is between 0.4 and 0.

95. When the ratio of r / R gradually increases, the angle value of A1 also gradually increases, and the angle value of A1 is between 5° and 43°.

2. The axial flow fan blade according to claim 1, characterized in that: The intersection point of the cylinder S and the leading edge (21) of the blade is C, the line connecting C and the center of the hub (10) is L4, the tangent of the leading edge (21) of the blade at point C is L5, and the angle between L5 and L4 is the leading edge guide bending angle A2, wherein when the ratio r / R gradually increases, the angle value of A2 also gradually increases, and the angle value of A2 is between 29° and 59°.

3. The axial flow fan blade according to claim 1, characterized in that: The intersection point of the cylinder S and the trailing edge (22) of the blade is D, the line connecting D and the center of the hub (10) is L6, the tangent line of the trailing edge (22) of the blade at point D is L7, and the angle between L7 and L6 is the trailing edge guide bending angle A3, wherein, when the ratio r / R gradually increases, the angle value of A3 also gradually increases, and the angle value of A3 is between 31° and 42°.

4. The axial flow fan blade according to claim 1, characterized in that: The angle between the chord length of the cross section obtained by the intersection of the cylinder S and the blade (20) and the rotation plane of the blade (20) is the blade installation angle Q, wherein when the ratio r / R gradually increases, the angle value of Q gradually decreases, and the angle value of Q is between 32.5° and 28°.

5. The axial flow fan blade according to claim 1, characterized in that: The chord length of the cross section formed by the intersection of the cylinder S and the blade (20) is b, wherein when the ratio r / R gradually increases, the ratio b / R also gradually increases, and the ratio b / R is between 0.5 and 1.

5.

6. The axial flow fan blade according to claim 1, characterized in that: An included angle α is provided between the leading edge (21) of the blade and the blade tip (23) of the blade, and the angle value of α is between 40° and 50°.

7. The axial flow fan blade according to claim 1, characterized in that: The maximum diameter of the blade (20) is d1, and the diameter of the hub (10) is d2, wherein the ratio d2 / d1 is between 0.25 and 0.

35.

8. The axial flow fan blade according to any one of claims 1 to 7, characterized in that: The axial flow fan blade comprises a plurality of blades (20), and the number of the plurality of blades (20) is an odd number.

9. A fan, characterized in that: The fan comprises the axial flow fan blade according to any one of claims 1 to 8.

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