Double-blade opposite axial flow fan blade and air supply device using same

Abstract

The utility model relates to the technical field of fan blades, and discloses a double-blade opposite axial flow fan blade and an air supply device using the same, the double-blade opposite axial flow fan blade comprises a hub and a plurality of blade groups annularly and uniformly distributed on the peripheral surface of the hub, each blade group comprises a front bent blade and a rear bent blade, and the front bent blades and the rear bent blades are respectively and obliquely arranged relative to the axis of the hub. By means of the front bent blades and the rear bent blades which are alternately arranged, the centripetal force of the front bent blades and the centrifugal force of the rear bent blades can be integrated by means of the opposite bending directions of the front bent blades and the rear bent blades; therefore, the problems of noise and energy loss caused by airflow path extension due to centripetal airflow gathering caused by unidirectional forward bending inertia force and centrifugal airflow dispersion caused by unidirectional backward bending are solved.

Description

Technical Field

[0001] This utility model relates to the field of wind turbine blade technology, and in particular to a double-bladed relative axial flow wind turbine blade and an air supply device using the same. Background Technology

[0002] As a core component of household electric fans and industrial large fans, the design and function of the fan blades are crucial to the overall performance of the equipment.

[0003] Most current wind turbine blades use blades that curve forward or backward. The centripetal airflow caused by the inertial force of the blades that curve forward and the centrifugal airflow caused by the blades that curve backward will lead to a longer airflow path, which will increase noise and cause energy loss. Utility Model Content

[0004] To address the aforementioned shortcomings, the purpose of this invention is to propose a double-bladed relative axial flow fan blade and air delivery device. This solves the problem that most current fan blades use blades that are bent forward or backward. The centripetal airflow caused by the inertial force of the blades that are bent forward and the centrifugal airflow caused by the blades that are bent backward lead to an extended airflow path, which increases noise and causes energy loss.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A dual-blade axial flow fan blade includes a hub and a plurality of blade groups evenly distributed in an annular shape on the outer circumferential surface of the hub;

[0007] The blade assembly includes a forward-curved blade and a backward-curved blade. The forward-curved blade and the backward-curved blade are respectively inclined relative to the axis of the hub. The forward-curved blade and the backward-curved blade each include a blade root and a blade tip. The blade root is connected to the hub. The blade tip is located at the end of the forward-curved blade / the backward-curved blade that extends radially from the hub and extends smoothly from the blade root to the blade tip.

[0008] The same forward-curved blade has a leading edge and a trailing edge between its root and tip. The leading edge of the forward-curved blade is located in front of its trailing edge along the blade's rotation direction. The leading edge and trailing edge of the forward-curved blade are curved into an arc shape in the blade's rotation direction. The same backward-curved blade has a leading edge and a trailing edge between its root and tip. The leading edge of the backward-curved blade is located in front of its trailing edge along the blade's rotation direction. The leading edge and trailing edge of the backward-curved blade are curved into an arc shape, and the curvature direction of the leading edge and trailing edge of the backward-curved blade is opposite to that of the forward-curved blade in the same blade group. The plane formed by the tip of the backward-curved blade and the tip of the forward-curved blade in the same blade group intersects with the blade's rotation plane. Several forward-curved blades and backward-curved blades are alternately arranged on the outer circumferential surface of the hub.

[0009] Preferably, in the same blade group, the forward-curved blade and the backward-curved blade form an airflow channel, and the orthographic projection of the airflow channel onto the blade rotation plane is approximately elliptical.

[0010] Preferably, the projection of the intersection of the leading edge of the forward-curving blade and the outer periphery of the hub onto the blade's rotation plane is a0, and the projection of the outer edge point with the largest rotation radius of the forward-curving blade onto the blade's rotation plane is a. e ;

[0011] The projection of the intersection of the trailing edge of the backward-curved blade and the outer periphery of the hub onto the blade's rotation plane is b0, and the projection of the outer edge point with the largest rotation radius of the forward-curved blade onto the blade's rotation plane is b. e ;

[0012] Define a1, a2, ..., a n The projection line of the leading edge of the forward-curved blade onto the plane of blade rotation is from a0 to a. e The points that divide the space into equal parts, and a1, a2, ..., a n Arranged sequentially starting from the side closest to a0, where n is a natural number greater than 0;

[0013] Define b1, b2, ..., b n The projection line of the trailing edge of the backward-curved blade onto the plane of blade rotation is from b0 to b. e The points that divide the triangle into equal parts, and b1, b2, ..., b n Arranged sequentially starting from the side closest to b0, where n is a natural number greater than 0;

[0014] If a n Located at b n If the direction of rotation is forward, then define a. n and b n The spacing is the length ab of the line connecting them. n If a n Located at b n If the direction of rotation is backward, then define a. n and b n The spacing is the negative of the length of the line connecting them, -ab. n ;

[0015] In the same blade group, a1 and b1, a2 and b2, ..., a n and b n The distance between the two points first increases and then decreases.

[0016] Preferably, the projection of the intersection of the trailing edge of the forward-curving blade and the outer periphery of the hub onto the blade's rotation plane is c0, and the projection of the outer edge point with the largest rotation radius of the forward-curving blade onto the blade's rotation plane is a. e ;

[0017] The projection of the intersection of the leading edge of the backward-curved blade and the outer periphery of the hub onto the blade's rotation plane is d0, and the projection of the outer edge point of the forward-curved blade with the largest rotation radius onto the blade's rotation plane is b. e ;

[0018] Define c1, c2, ..., c n The projection line of the leading edge of the forward-curved blade onto the plane of blade rotation is from c0 to a. e The points that divide the triangle into equal parts, and c1, c2, ..., c n Arranged sequentially starting from the side closest to c0, where n is a natural number greater than 0;

[0019] Define d1, d2, ..., d n The projection line of the trailing edge of the backward-curved blade onto the plane of blade rotation is from d0 to b. e The points that divide the y-axis equally, and d1, d2, ..., d2. n Arranged sequentially starting from the side closest to d0, where n is a natural number greater than 0;

[0020] If c n Located at d n If the direction of rotation is forward, then c is defined. n and d n The spacing is the length cd of the line connecting them. n If c n Located at d n If the direction of rotation is backward, then c is defined. n and d n The spacing is the negative of the length of the line connecting them, -cd n ;

[0021] In the same blade group, c1 and d1, c2 and d2, ..., c n and d n The distance between the two points first increases and then decreases.

[0022] Preferably, the projection of the intersection of the trailing edge of the forward-curving blade and the outer periphery of the hub onto the blade's rotation plane is c0, and the projection of the outer edge point with the largest rotation radius of the forward-curving blade onto the blade's rotation plane is a. e ;

[0023] The projection of the intersection of the leading edge of the backward-curved blade and the outer periphery of the hub onto the blade's rotation plane is d0, and the projection of the outer edge point of the forward-curved blade with the largest rotation radius onto the blade's rotation plane is b. e ;

[0024] Define c1, c2, ..., c m c m+1 ... c nThe projection line of the leading edge of the forward-curved blade onto the plane of blade rotation is from c0 to a. e The points that divide the triangle, and c1, c2, ..., c m c m+1 ... c n Arrange them sequentially starting from the side closest to c0, where m is a natural number greater than 0, n is a natural number greater than m, and m≥2 / 3n;

[0025] Define d1, d2, ..., d m d m+1 、……、d n The projection line of the trailing edge of the backward-curved blade onto the plane of blade rotation is from d0 to b. e The points that divide the y-axis equally, and d1, d2, ..., d2. m d m+1 ... d n Arrange them sequentially starting from the side closest to d0, where m is a natural number greater than 0, n is a natural number greater than m, and m≥2 / 3n;

[0026] If c n Located at d n If the direction of rotation is forward, then c is defined. n and d n The spacing is the length cd of the line connecting them. n If c n Located at d n If the direction of rotation is backward, then c is defined. n and d n The spacing is the negative of the length of the line connecting them, -cd n ;

[0027] In the same blade group, c1 and d1, c2 and d2, ..., c m and d m The spacing first increases and then decreases, c m and d m c m+1 and d m+1 ... c n and d n The spacing gradually increases.

[0028] Preferably, the forward-curved blade has a first region with a rotation radius less than R1 and greater than the wheel housing radius R0, and the backward-curved blade has a second region with a rotation radius less than R2 and greater than the wheel housing radius R0. The projection L1 of the chord length of the blade in the first region and the second region onto the blade rotation plane gradually increases from the inside to the outside along the rotation radius.

[0029] Preferably, the forward-curving blade has a third region with a rotation radius greater than R3 and smaller than the rotation radius R5 of the outer edge of the forward-curving blade, and the backward-curving blade has a fourth region with a rotation radius greater than R4 and smaller than the rotation radius R6 of the outer edge of the backward-curving blade. The projection L2 of the blade chord length on the wind turbine's rotation plane in the third and fourth regions gradually decreases from the inside to the outside along the rotation radius.

[0030] Preferably, the forward-curved blade is provided with a fifth region having a rotation radius greater than or equal to R1 and less than or equal to R3, and the backward-curved blade is provided with a sixth region having a rotation radius greater than or equal to R2 and less than or equal to R4. The projection L3 of the chord length of the blade in the wind turbine rotation plane remains unchanged in the fifth region and the sixth region.

[0031] Preferably, the projection of the midpoint of the line connecting the forward-curved blade and the hub onto the blade's rotation plane is A, the projection of the hub's axis onto the blade's rotation plane is O, and the projection of the outer edge point of the forward-curved blade with the largest rotation radius onto the blade's rotation plane is a. e The line connecting A and O and O and a e The lines connecting them form an included angle φ;

[0032] The projection of the midpoint of the line connecting the backward-curved blade and the hub onto the blade's rotation plane is B; the projection of the hub's axis onto the blade's rotation plane is O; and the projection of the outer edge point of the backward-curved blade with its largest rotation radius onto the blade's rotation plane is b. e The line connecting B and O and O and b e The lines connecting them form an included angle φ';

[0033] O、a e The connection between O and b e The lines connecting them form an included angle β;

[0034] The included angles φ and φ' range from 10° to 30°, and the included angle β ranges from 5° to 15°.

[0035] An air supply device includes a housing, a rotary driver, and the aforementioned dual-blade opposing axial flow fan blades. The rotary driver is mounted on the housing, and the dual-blade opposing axial flow fan blades are rotatably mounted on the rotary output end of the rotary driver. The rotary driver is used to drive the dual-blade opposing axial flow fan blades to rotate.

[0036] The technical solution provided by this utility model can include the following beneficial effects:

[0037] By alternating forward-curving and backward-curving blades, and by using the relatively opposite bending directions of the forward-curving and backward-curving blades, the centripetal force of the forward-curving blades and the centrifugal force of the backward-curving blades can be combined. This improves the noise and energy loss caused by the centripetal airflow convergence caused by the inertial force of unidirectional forward curvature and the centrifugal airflow divergence caused by unidirectional backward curvature, which leads to the extension of the airflow path.

[0038] The spacing between the forward-curving blades and the backward-curving blades in the middle section of the blades is appropriately increased to enhance the counter-impact effect. The spacing gradually decreases on the outer part of the blades away from the hub to solve the problem of noise caused by excessive counter-impact due to excessive rotational linear velocity on the outer side of the blades.

[0039] In the same blade group, the overall projected profile formed by the leading edge of the forward-curved blade and the trailing edge of the backward-curved blade is an elliptical structure. The overall area of ​​the middle section of the blade group is increased to ensure the overall air volume, while the overall area of ​​the outer edge of the blade group is appropriately reduced to reduce the noise of the outer edge of the blade rotation.

[0040] In the same blade group, the overall projected profile formed by the trailing edge of the forward-curved blade and the leading edge of the backward-curved blade is an elliptical structure, which can further increase the counter-shock effect and avoid excessive counter-shock and noise at the outer edge of the rotating blade.

[0041] At the outer edge of the rotating blade, the distance between the forward-curving blade and the backward-curving blade is relatively large compared to the hub, which weakens the counter-shock effect. Increasing the distance between the forward-curving blade and the backward-curving blade again increases the counter-shock effect.

[0042] The first and second regions of the fan blades near the hub have smaller radii of rotation. The chord length gradually increases from the inside to the outside along the radii of rotation to increase the area of ​​the fan blades, ensuring airflow and increasing the counter-current effect.

[0043] The middle section of the fan blades has a fifth and a sixth zone, which smoothly transitions and ensures the overall air volume and counter-current effect.

[0044] If the included angles φ, φ', and β are too small, the wake streamline of the backward-curved blades will impact the inflow of the forward-curved blades; if the angles are too large, they will not have a counteracting effect. Attached Figure Description

[0045] Figure 1 This is a three-dimensional structural diagram of one embodiment of the present invention.

[0046] Figure 2 This is a projection view of an embodiment of the present invention on the plane of the fan blade rotation.

[0047] Figure 3 This is a schematic diagram of the structure of one embodiment of the present invention.

[0048] Figure 4This is a partially enlarged schematic diagram of one embodiment of the present invention.

[0049] Figure 5 This is a three-dimensional structural diagram of another embodiment of the present invention.

[0050] Among them: hub 1, first area 101, second area 102, third area 103, fourth area 104, fifth area 105, sixth area 106, blade root 11, blade tip 12, leading edge 13, trailing edge 14, forward-curving blade 2, and backward-curving blade 3. Detailed Implementation

[0051] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0052] In the description of this utility model, it should be understood that the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They 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 this utility model. Furthermore, features defined with "first" and "second" may explicitly or implicitly include one or more of these features, used to distinguish and describe features, without any order or emphasis.

[0053] In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0054] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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 mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0055] The embodiments of this utility model are described below with reference to the accompanying drawings.

[0056] A dual-blade axial flow fan blade includes a hub 1 and a plurality of blade groups evenly distributed in an annular shape on the outer circumferential surface of the hub 1.

[0057] The blade assembly includes a forward-curved blade 2 and a backward-curved blade 3. The forward-curved blade 2 and the backward-curved blade 3 are respectively inclined relative to the axis of the hub 1. The forward-curved blade 2 and the backward-curved blade 3 each include a blade root 11 and a blade tip 12. The blade root 11 is connected to the hub 1. The blade tip 12 is located at the end of the forward-curved blade 2 / the backward-curved blade 3 that extends radially from the hub 1, and extends smoothly from the blade root 11 to the blade tip 12.

[0058] A leading edge 13 and a trailing edge 14 are provided between the blade root 11 and the blade tip 12 of the same forward-curved blade 2. The leading edge 13 of the forward-curved blade 2 is located in front of its trailing edge 14 along the blade rotation direction. The leading edge 13 and the trailing edge 14 of the forward-curved blade 2 are curved into an arc shape in the blade rotation direction. A leading edge 13 and a trailing edge 14 are provided between the blade root 11 and the blade tip 12 of the same backward-curved blade 3. The leading edge 13 of the backward-curved blade 3 is located in front of its trailing edge 14 along the blade rotation direction. The leading edge 13 and the trailing edge 14 of the backward-curved blade 3 are curved into an arc shape, and the bending direction of the leading edge 13 and the trailing edge 14 of the backward-curved blade 3 is opposite to the bending direction of the forward-curved blade 2 in the same blade group. The plane formed by the blade tip 12 of the backward-curved blade 3 and the blade tip 12 of the forward-curved blade 2 in the same blade group intersects with the blade rotation plane. A plurality of forward-curved blades 2 and backward-curved blades 3 are alternately arranged on the outer peripheral surface of the hub 1.

[0059] like Figure 1 , Figure 3 and Figure 5 As shown ( Figure 1 (The middle arrow indicates the rotation direction of the two blades relative to the axial flow fan blades). By alternately setting the forward-curved blades 2 and the backward-curved blades 3, and by using the relatively opposite bending directions of the forward-curved blades 2 and the backward-curved blades 3, the centripetal force of the forward-curved blades 2 and the centrifugal force of the backward-curved blades 3 can be combined. This improves the noise and energy loss caused by the centripetal airflow convergence caused by the inertial force of the unidirectional forward curvature and the centrifugal airflow divergence caused by the unidirectional backward curvature, which leads to the extension of the airflow path.

[0060] Preferably, in the same blade group, the forward-curved blade 2 and the backward-curved blade 3 form an airflow channel, and the orthographic projection of the airflow channel onto the blade rotation plane is approximately elliptical.

[0061] like Figure 2 As shown, the part filled with diagonal lines is the orthographic projection of the airflow channel onto the plane of blade rotation. The arrows in the figure indicate the rotation direction of the two blades relative to the axial flow blades. The spacing between the forward-curved blade 2 and the backward-curved blade 3 is appropriately increased in the middle section of the blades to increase the counter-impact effect. The spacing gradually decreases in the outer part of the blades away from the hub 1 to solve the problem of noise caused by excessive counter-impact due to excessive rotational linear velocity on the outer side of the blades.

[0062] Preferably, the projection of the intersection point of the leading edge 13 of the forward-curved blade 2 and the outer periphery of the hub 1 onto the wind turbine rotation plane is a0, and the projection of the outer edge point with the largest rotation radius of the forward-curved blade 2 onto the wind turbine rotation plane is a. e ;

[0063] The projection of the intersection point of the trailing edge 14 of the rear-curved blade 3 and the outer periphery of the hub 1 onto the wind turbine rotation plane is b0, and the projection of the outer edge point of the front-curved blade 2 with the largest rotation radius onto the wind turbine rotation plane is b. e ;

[0064] Define a1, a2, ..., a n The projection line of the leading edge 13 of the forward-curved blade 2 onto the blade rotation plane is from a0 to a e The points that divide the space into equal parts, and a1, a2, ..., a n Arranged sequentially starting from the side closest to a0, where n is a natural number greater than 0;

[0065] Define b1, b2, ..., b n The projection line of the trailing edge 14 of the backward-curved blade 3 onto the blade rotation plane is from b0 to b e The points that divide the triangle into equal parts, and b1, b2, ..., b n Arranged sequentially starting from the side closest to b0, where n is a natural number greater than 0;

[0066] If a n Located at b n If the direction of rotation is forward, then define a. n and b n The spacing is the length ab of the line connecting them. n If a n Located at b n If the direction of rotation is backward, then define a. n and b n The spacing is the negative of the length of the line connecting them, -ab. n ;

[0067] In the same blade group, a1 and b1, a2 and b2, ..., a n and b n The distance between the two points first increases and then decreases.

[0068] In the same blade group, the overall projected profile formed by the leading edge 13 of the forward-curved blade 2 and the trailing edge 14 of the backward-curved blade 3 is an elliptical structure. The overall area of ​​the middle section of the blade group is increased to ensure the overall air volume, while the overall area of ​​the outer edge of the blade group is appropriately reduced to reduce the noise of the outer edge of the blade rotation.

[0069] Preferably, the projection of the intersection point of the trailing edge 14 of the forward-curved blade 2 and the outer periphery of the hub 1 onto the blade rotation plane is c0, and the projection of the outer edge point with the largest rotation radius of the forward-curved blade 2 onto the blade rotation plane is a. e ;

[0070] The projection of the intersection point of the leading edge 13 of the backward-curved blade 3 and the outer periphery of the hub 1 onto the blade rotation plane is d0, and the projection of the outer edge point of the forward-curved blade 2 with the largest rotation radius onto the blade rotation plane is b. e ;

[0071] Define c1, c2, ..., c n The projection line of the leading edge 13 of the forward-curved blade 2 onto the blade rotation plane is from c0 to a. e The points that divide the triangle into equal parts, and c1, c2, ..., c n Arranged sequentially starting from the side closest to c0, where n is a natural number greater than 0;

[0072] Define d1, d2, ..., d n The projection line of the trailing edge 14 of the backward-curved blade 3 onto the blade rotation plane is from d0 to b. e The points that divide the y-axis equally, and d1, d2, ..., d2. n Arranged sequentially starting from the side closest to d0, where n is a natural number greater than 0;

[0073] If c n Located at d n If the direction of rotation is forward, then c is defined. n and d n The spacing is the length cd of the line connecting them. n If c n Located at d n If the direction of rotation is backward, then c is defined. n and d n The spacing is the negative of the length of the line connecting them, -cd n ;

[0074] In the same blade group, c1 and d1, c2 and d2, ..., c n and d n The distance between the two points first increases and then decreases.

[0075] In the same blade group, the overall projected profile formed by the trailing edge 14 of the forward-curved blade 2 and the leading edge 13 of the backward-curved blade 3 is an elliptical structure, which can further increase the counter-shock effect and avoid excessive counter-shock and noise at the outer edge of the rotating blade.

[0076] Preferably, the projection of the intersection point of the trailing edge 14 of the forward-curved blade 2 and the outer periphery of the hub 1 onto the blade rotation plane is c0, and the projection of the outer edge point with the largest rotation radius of the forward-curved blade 2 onto the blade rotation plane is a. e ;

[0077] The projection of the intersection point of the leading edge 13 of the backward-curved blade 3 and the outer periphery of the hub 1 onto the blade rotation plane is d0, and the projection of the outer edge point of the forward-curved blade 2 with the largest rotation radius onto the blade rotation plane is b. e ;

[0078] Define c1, c2, ..., c m c m+1 ... c n The projection line of the leading edge 13 of the forward-curved blade 2 onto the blade rotation plane is from c0 to a. e The points that divide the triangle, and c1, c2, ..., c m c m+1 ... c n Arrange them sequentially starting from the side closest to c0, where m is a natural number greater than 0, n is a natural number greater than m, and m≥2 / 3n;

[0079] Define d1, d2, ..., d m d m+1 ... d n The projection line of the trailing edge 14 of the backward-curved blade 3 onto the blade rotation plane is from d0 to b. e The points that divide the y-axis equally, and d1, d2, ..., d2. m d m+1 ... d n Arrange them sequentially starting from the side closest to d0, where m is a natural number greater than 0, n is a natural number greater than m, and m≥2 / 3n;

[0080] If c n Located at d n If the direction of rotation is forward, then c is defined. n and d n The spacing is the length cd of the line connecting them. n If c n Located at d n If the direction of rotation is backward, then c is defined. n and d n The spacing is the negative of the length of the line connecting them, -cd n ;

[0081] In the same blade group, c1 and d1, c2 and d2, ..., c m and d m The spacing first increases and then decreases, c m and d m cm+1 and d m+1 ... c n and d n The spacing gradually increases.

[0082] At the outer edge of the rotating blade, the distance between the forward-curving blade 2 and the backward-curving blade 3 is relatively large compared to the hub 1, which weakens the counter-shock effect. To further increase the distance between the forward-curving blade 2 and the backward-curving blade 3, the counter-shock effect is enhanced.

[0083] Preferably, the forward-curved blade 2 is provided with a first region 101 with a rotation radius less than R1 and greater than the wheel housing radius R0, and the backward-curved blade 3 is provided with a second region 102 with a rotation radius less than R2 and greater than the wheel housing radius R0. The projection L1 of the chord length of the blades in the first region 101 and the second region 102 onto the blade rotation plane gradually increases from the inside to the outside along the rotation radius.

[0084] like Figure 4 As shown (the arrow in the figure indicates the rotation direction of the two blades relative to the axial flow fan blades), the rotation radius of the fan blades in the first region 101 and the second region 102 near the hub 1 is small. The chord length gradually increases from the inside to the outside along the rotation radius to increase the area of ​​the fan blades, ensuring the air volume and increasing the counter-current effect.

[0085] Preferably, the forward-curving blade 2 is provided with a third region 103 having a rotation radius greater than R3 and smaller than the rotation radius R5 of the outer edge of the forward-curving blade 2, and the backward-curving blade 3 is provided with a fourth region 104 having a rotation radius greater than R4 and smaller than the rotation radius R6 of the outer edge of the backward-curving blade 3, wherein... The projection L2 of the blade chord length on the blade rotation plane in the third region (103) and the fourth region (104) gradually decreases from the inside to the outside along the rotation radius.

[0086] The rotation radius of the fan blades in the third region 103 and the fourth region 104, which are far away from the hub 1, is relatively large. The chord length gradually decreases from the inside to the outside along the rotation radius to reduce the area of ​​the fan blades, thereby reducing the counter-impact effect and noise.

[0087] Preferably, the forward-curved blade 2 is provided with a fifth region 105 with a rotation radius greater than or equal to R1 and less than or equal to R3, and the backward-curved blade 3 is provided with a sixth region 106 with a rotation radius greater than or equal to R2 and less than or equal to R4. The projection L3 of the chord length of the blade in the wind turbine rotation plane remains unchanged in the fifth region 105 and the sixth region 106.

[0088] The middle section of the fan blade has a fifth zone 105 and a sixth zone 106, which smoothly transition and ensure the overall air volume and counter-current effect.

[0089] Preferably, the projection of the midpoint of the connecting line between the forward-curved blade 2 and the hub 1 onto the wind turbine's rotation plane is A, the projection of the axis of the hub 1 onto the wind turbine's rotation plane is O, and the projection of the outer edge point of the forward-curved blade 2 with the largest rotation radius onto the wind turbine's rotation plane is a. e The line connecting A and O and O and a e The lines connecting them form an included angle φ;

[0090] The projection of the midpoint of the line connecting the backward-curved blade 3 and the hub 1 onto the wind turbine's rotation plane is B; the projection of the axis of the hub 1 onto the wind turbine's rotation plane is O; and the projection of the outer edge point of the backward-curved blade 3 with its largest rotation radius onto the wind turbine's rotation plane is b. e The line connecting B and O and O and b e The lines connecting them form an included angle φ';

[0091] O、a e The connection between O and b e The lines connecting them form an included angle β;

[0092] The included angles φ and φ' range from 10° to 30°, and the included angle β ranges from 5° to 15°.

[0093] If the included angles φ, φ', and β are too small, the wake streamline of the backward-curved blade 3 will impact the inflow of the forward-curved blade 2; if the angles are too large, they will not have a counteracting effect.

[0094] In one embodiment, the rotation radius of the outer edge of the forward-curved blade 2 is the same as the rotation radius of the outer edge of the backward-curved blade 3.

[0095] In another embodiment, the rotation radius of the outer edge of the forward-curved blade 2 is different from the rotation radius of the outer edge of the backward-curved blade 3.

[0096] Preferably, the blade tips 12 of the forward-curved blade 2 and the backward-curved blade 3 are arc-shaped.

[0097] In a specific embodiment, the blade tips 12 of both the forward-curved blade 2 and the backward-curved blade 3 are provided with arc-shaped chamfers to avoid the overlapping projections of the blade tips 12 on the wind turbine rotation plane, thereby avoiding energy loss and noise, while also taking into account aesthetics and safety.

[0098] An air supply device includes a housing, a rotary driver, and the aforementioned dual-blade opposing axial flow fan blades. The rotary driver is mounted on the housing, and the dual-blade opposing axial flow fan blades are rotatably mounted on the rotary output end of the rotary driver. The rotary driver is used to drive the dual-blade opposing axial flow fan blades to rotate.

[0099] Other configurations and operations according to the embodiments of this utility model are known to those skilled in the art and will not be described in detail here.

[0100] In this specification, the terms "embodiment," "example," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0101] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A double-bladed relative axial flow fan blade, characterized in that: It includes a hub and a plurality of blade groups evenly distributed in an annular shape on the outer circumferential surface of the hub; The blade assembly includes a forward-curved blade and a backward-curved blade. The forward-curved blade and the backward-curved blade are respectively inclined relative to the axis of the hub. The forward-curved blade and the backward-curved blade each include a blade root and a blade tip. The blade root is connected to the hub. The blade tip is located at the end of the forward-curved blade / the backward-curved blade that extends radially from the hub and extends smoothly from the blade root to the blade tip. The same forward-curved blade has a leading edge and a trailing edge between its root and tip. The leading edge of the forward-curved blade is located in front of its trailing edge along the blade's rotation direction. The leading edge and trailing edge of the forward-curved blade are curved into an arc shape in the blade's rotation direction. The same backward-curved blade has a leading edge and a trailing edge between its root and tip. The leading edge of the backward-curved blade is located in front of its trailing edge along the blade's rotation direction. The leading edge and trailing edge of the backward-curved blade are curved into an arc shape, and the curvature direction of the leading edge and trailing edge of the backward-curved blade is opposite to that of the forward-curved blade in the same blade group. The plane formed by the tip of the backward-curved blade and the tip of the forward-curved blade in the same blade group intersects with the blade's rotation plane. Several forward-curved blades and backward-curved blades are alternately arranged on the outer circumferential surface of the hub.

2. The double-bladed relative axial flow fan blade according to claim 1, characterized in that: In the same blade group, the forward-curved blade and the backward-curved blade form an airflow channel, and the orthographic projection of the airflow channel onto the blade rotation plane is approximately elliptical.

3. A double-bladed relative axial flow fan blade according to claim 2, characterized in that: The projection of the intersection of the leading edge of the forward-curved blade and the outer periphery of the hub onto the blade's rotation plane is a0, and the projection of the outer edge point with the largest rotation radius of the forward-curved blade onto the blade's rotation plane is a. e ; The projection of the intersection of the trailing edge of the backward-curved blade and the outer periphery of the hub onto the blade's rotation plane is b0, and the projection of the outer edge point with the largest rotation radius of the forward-curved blade onto the blade's rotation plane is b. e ; Define a1, a2, ..., a n The projection line of the leading edge of the forward-curved blade onto the plane of blade rotation is from a0 to a. e The points that divide the space into equal parts, and a1, a2, ..., a n Arranged sequentially starting from the side closest to a0, where n is a natural number greater than 0; Define b1, b2, ..., b n The projection line of the trailing edge of the backward-curved blade onto the plane of blade rotation is from b0 to b. e The points that divide the triangle into equal parts, and b1, b2, ..., b n Arranged sequentially starting from the side closest to b0, where n is a natural number greater than 0; If a n Located at b n If the direction of rotation is forward, then define a. n and b n The spacing is the length ab of the line connecting them. n If a n Located at b n If the direction of rotation is backward, then define a. n and b n The spacing is the negative of the length of the line connecting them, -ab. n ; In the same blade group, a1 and b1, a2 and b2, ..., a n and b n The distance between the two points first increases and then decreases.

4. A double-bladed relative axial flow fan blade according to claim 2, characterized in that: The projection of the intersection of the trailing edge of the forward-curved blade and the outer periphery of the hub onto the blade's rotation plane is c0, and the projection of the outer edge point with the largest rotation radius of the forward-curved blade onto the blade's rotation plane is a. e ; The projection of the intersection of the leading edge of the backward-curved blade and the outer periphery of the hub onto the blade's rotation plane is d0, and the projection of the outer edge point of the forward-curved blade with the largest rotation radius onto the blade's rotation plane is b. e ; Define c1, c2, ..., c n The projection line of the leading edge of the forward-curved blade onto the plane of blade rotation is from c0 to a. e The points that divide the triangle into equal parts, and c1, c2, ..., c n Arranged sequentially starting from the side closest to c0, where n is a natural number greater than 0; Define d1, d2, ..., d n The projection line of the trailing edge of the backward-curved blade onto the plane of blade rotation is from d0 to b. e The points that divide the y-axis equally, and d1, d2, ..., d2. n Arranged sequentially starting from the side closest to d0, where n is a natural number greater than 0; If c n Located at d n If the direction of rotation is forward, then c is defined. n and d n The spacing is the length cd of the line connecting them. n If c n Located at d n If the direction of rotation is backward, then c is defined. n and d n The spacing is the negative of the length of the line connecting them, -cd n ; In the same blade group, c1 and d1, c2 and d2, ..., c n and d n The distance between the two points first increases and then decreases.

5. A double-bladed relative axial flow fan blade according to claim 2, characterized in that: The projection of the intersection of the trailing edge of the forward-curved blade and the outer periphery of the hub onto the blade's rotation plane is c0, and the projection of the outer edge point with the largest rotation radius of the forward-curved blade onto the blade's rotation plane is a. e ; The projection of the intersection of the leading edge of the backward-curved blade and the outer periphery of the hub onto the blade's rotation plane is d0, and the projection of the outer edge point of the forward-curved blade with the largest rotation radius onto the blade's rotation plane is b. e ; Define c1, c2, ..., c m c m+1 ... c n The projection line of the leading edge of the forward-curved blade onto the plane of blade rotation is from c0 to a. e The points that divide the triangle, and c1, c2, ..., c m c m+1 ... c n Arrange them sequentially starting from the side closest to c0, where m is a natural number greater than 0, n is a natural number greater than m, and m≥2 / 3n; Define d1, d2, ..., d m d m+1 ... d n The projection line of the trailing edge of the backward-curved blade onto the plane of blade rotation is from d0 to b. e The points that divide the y-axis equally, and d1, d2, ..., d2. m d m+1 ... d n Arrange them sequentially starting from the side closest to d0, where m is a natural number greater than 0, n is a natural number greater than m, and m≥2 / 3n; If c n Located at d n If the direction of rotation is forward, then c is defined. n and d n The spacing is the length cd of the line connecting them. n If c n Located at d n If the direction of rotation is backward, then c is defined. n and d n The spacing is the negative of the length of the line connecting them, -cd n ; In the same blade group, c1 and d1, c2 and d2, ..., c m and d m The spacing first increases and then decreases, c m and d m c m+1 and d m+1 ... c n and d n The spacing gradually increases.

6. A double-bladed relative axial flow fan blade according to claim 1, characterized in that: The forward-curved blade has a first region with a rotation radius less than R1 and greater than the wheel housing radius R0, and the backward-curved blade has a second region with a rotation radius less than R2 and greater than the wheel housing radius R0. The projection L1 of the blade chord length on the wind turbine rotation plane in the first region and the second region gradually increases from the inside to the outside along the rotation radius.

7. A double-bladed relative axial flow fan blade according to claim 6, characterized in that: The forward-curved blade has a third region with a rotation radius greater than R3 and smaller than the rotation radius R5 of the outer edge of the forward-curved blade, and the backward-curved blade has a fourth region with a rotation radius greater than R4 and smaller than the rotation radius R6 of the outer edge of the backward-curved blade. The projection L2 of the blade chord length on the wind turbine's rotation plane in the third and fourth regions gradually decreases from the inside to the outside along the rotation radius.

8. A double-bladed relative axial flow fan blade according to claim 7, characterized in that: The forward-curved blade has a fifth region with a rotation radius greater than or equal to R1 and less than or equal to R3, and the backward-curved blade has a sixth region with a rotation radius greater than or equal to R2 and less than or equal to R4. The projection L3 of the chord length of the blade in the wind turbine rotation plane remains unchanged in the fifth region and the sixth region.

9. A double-bladed relative axial flow fan blade according to claim 1, characterized in that: The projection of the midpoint of the line connecting the forward-curved blade and the hub onto the plane of blade rotation is A; the projection of the hub's axis onto the plane of blade rotation is O; and the projection of the outer edge point of the forward-curved blade with the largest radius of rotation onto the plane of blade rotation is a. e The line connecting A and O and O and a e The lines connecting them form an included angle φ; The projection of the midpoint of the line connecting the backward-curved blade and the hub onto the blade's rotation plane is B; the projection of the hub's axis onto the blade's rotation plane is O; and the projection of the outer edge point of the backward-curved blade with its largest rotation radius onto the blade's rotation plane is b. e The line connecting B and O and O and b e The lines connecting them form an included angle φ'; O、a e The connection between O and b e The lines connecting them form an included angle β; The included angles φ and φ' range from 10° to 30°, and the included angle β ranges from 5° to 15°.

10. An air supply device, characterized in that: The device includes a housing, a rotary actuator, and a double-bladed relative axial flow fan blade as described in any one of claims 1-9. The rotary actuator is mounted on the housing, and the double-bladed relative axial flow fan blade is rotatably mounted on the rotary output end of the rotary actuator. The rotary actuator is used to drive the double-bladed relative axial flow fan blade to rotate.

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