Impeller assembly and wind turbine
By introducing flap blades into the impeller assembly, the problems of low wind energy utilization and vibration noise have been solved, achieving more efficient wind energy conversion and reducing operating costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GD MIDEA AIR CONDITIONING EQUIP CO LTD
- Filing Date
- 2025-01-24
- Publication Date
- 2026-07-24
Smart Images
Figure CN122447255A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of airflow generation technology, and more particularly to impeller assemblies and wind turbines. Background Technology
[0002] With the continuous development of the wind power industry, the large-scale utilization of wind power has effectively alleviated the power shortage problem. However, wind turbines face various complex environmental factors in actual operation, such as turbulence, wind speed, and wind direction. These factors affect wind energy utilization and have a significant impact on the performance of wind turbines. Therefore, wind turbine design is a key factor in the development of the wind power industry. As the core component of a wind turbine, the design and performance of the rotor assembly are central to wind turbine research and development; however, current rotor assemblies have relatively low wind energy utilization rates. Summary of the Invention
[0003] The present invention aims to at least solve one of the technical problems existing in the related art. To this end, the present invention proposes an impeller assembly that occupies little space and is lightweight, and that this impeller assembly can reduce aerodynamic interference, vibration and noise, and improve wind energy utilization.
[0004] The present invention also proposes a wind turbine.
[0005] An impeller assembly according to a first aspect of the present invention includes: Wheel hub; Multiple sets of blades are distributed on the outer periphery of the hub. Each set of blades includes a main wing blade and a flap blade. The main wing blade is connected to the hub. The flap blade is located on the side where the pressure surface of the main wing blade is located. The flap blade is connected to the main wing blade, and there is a gap between the main wing blade and the flap blade. The flap blade is located at the trailing edge of the main wing blade.
[0006] According to the impeller assembly of this application embodiment, each set of blades includes a main wing blade and a flap blade. A gap exists between the main wing blade and the flap blade, allowing the flap blade to avoid airflow interference from the main wing blade and prevent vibration and noise. The flap blade is located at the trailing edge of the main wing blade, that is, downstream of the main wing blade along the airflow direction. The flap blade can increase the lift of the airflow at the trailing edge of the main wing blade, thereby improving the efficiency of the impeller assembly. Furthermore, since the flap blade is located on the pressure surface of the main wing blade, the flap blade can further utilize the space on the windward side of the main wing blade, improving the space utilization rate of the impeller assembly and increasing the lift of the impeller assembly without significantly increasing the space and weight occupied by the impeller assembly.
[0007] According to one embodiment of the present invention, the flap blade is positioned corresponding to the tip position of the main wing blade.
[0008] According to one embodiment of the present invention, the ratio of the blade height of the flap blade to the blade height of the main wing blade is 1 / 4 to 1 / 2.
[0009] According to one embodiment of the present invention, the ratio of the blade height of the flap blade to the blade height of the main wing blade is 1 / 3.
[0010] According to one embodiment of the present invention, the gap is 2mm-6mm.
[0011] According to an embodiment of the present invention, for the same blade height, the relationship between the first chord length of the main wing blade and the second chord length of the flap blade satisfies: 1 / 4 × first chord length ≤ second chord length ≤ first chord length.
[0012] According to one embodiment of the present invention, the main airfoil blade and the flap blade overlap circumferentially along the hub, and the relationship between the width L1 of the overlapping portion and the second chord length of the flap blade satisfies: 0.25 × second chord length ≤ L1 ≤ 0.5 × second chord length.
[0013] According to one embodiment of the present invention, the main wing blade and the flap blade overlap circumferentially along the hub, and the ratio I of the width L1 of the overlapping portion and the second chord length of the flap blade satisfies the following: the ratio I gradually decreases from the blade root to the blade tip.
[0014] According to one embodiment of the present invention, the inclination angle of the first chord length of the main wing blade is greater than the inclination angle of the second chord length of the flap blade.
[0015] According to one embodiment of the present invention, the main wing blade and the flap blade are connected by a bridging structure.
[0016] According to one embodiment of the present invention, the leading edge of the main airfoil extends in a straight line and is swept back, with a sweep angle of 20°±5°. And / or, The leading edge of the flap blade is curved backward from the leaf root to 55%-65% of the leaf height, and then curved forward from 55%-65% of the leaf height to the leaf tip. And / or, From the leaf root to the leaf tip, the chord length of the blade gradually decreases.
[0017] According to one embodiment of the present invention, the impeller assembly further includes: A collector is arranged around the blade, and there is a gap between the tip of the main wing blade and the collector, and a gap between the tip of the flap blade and the collector.
[0018] A wind turbine according to a second aspect of the present invention includes: Organism; The aforementioned impeller assembly is installed on the machine body.
[0019] The wind turbine according to an embodiment of the present invention includes the above-described impeller assembly, and therefore has the technical effects of the above-described impeller assembly, which will not be repeated here.
[0020] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 This is an isometric schematic diagram of the impeller assembly of the present invention, wherein the impeller assembly does not include a collector.
[0023] Figure 2 This is one of the airfoil planar schematic diagrams of the impeller assembly of the present invention.
[0024] Figure 3 This is the second schematic diagram of the airfoil plan of the impeller assembly of the present invention.
[0025] Figure 4 This is one of the structural schematic diagrams of the impeller assembly including the collector according to the present invention.
[0026] Figure 5 This is a second schematic diagram of the impeller assembly including the collector according to the present invention.
[0027] Figure 6 This is the third schematic diagram of the impeller assembly including the collector of the present invention.
[0028] Figure 7 This is a three-dimensional view of the back of the impeller assembly of the present invention.
[0029] Figure 8 This is a schematic diagram of the structure of a prototype impeller in the prior art.
[0030] Figure label: 1. Main airfoil blade; 101. Pressure surface; 2. Flap blade; 3. Hub; 4. First bridging structure; 5. Collector; 6. Second bridging structure; 1a. Leading edge of main airfoil blade; 1b. Trailing edge of main airfoil blade; 1c. Tip of main airfoil blade; 2a. Leading edge of flap blade; 2b. Trailing edge of flap blade; 2c. Tip of flap blade; 10a. Inclination angle of the first cascade chord length; 10c. First cascade chord length; 20a. Inclination angle of the second cascade chord length; 20c. Second cascade chord length. Detailed Implementation
[0031] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.
[0032] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and 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. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0033] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" 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. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.
[0034] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0035] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," 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. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0036] Please see Figures 1 to 3 According to an embodiment of this application, the impeller assembly includes a hub 3 and multiple sets of blades (refer to main blade 1 and flap blade 2). The multiple sets of blades are distributed on the outer periphery of the hub 3. Each set of blades includes a main blade 1 and a flap blade 2. The main blade 1 is connected to the hub 3. The flap blade 2 is located on the side where the pressure surface 101 of the main blade 1 is located. The flap blade 2 is connected to the main blade 1, and there is a gap L2 between the main blade 1 and the flap blade 2. The flap blade 2 is located at the trailing edge of the main blade.
[0037] According to the impeller assembly of the present application embodiment, each set of blades includes a main airfoil blade 1 and a flap blade 2. A gap exists between the main airfoil blade 1 and the flap blade 2, allowing the flap blade 2 to avoid airflow interference from the main airfoil blade 1, preventing vibration and noise. The flap blade 2 is located at the trailing edge 1a of the main airfoil blade, that is, downstream of the main airfoil blade 1 along the airflow direction. The flap blade 2 can increase the lift of the airflow at the trailing edge 1b of the main airfoil blade, thereby improving the efficiency of the impeller assembly. Furthermore, since the flap blade 2 is located on the pressure surface 101 of the main airfoil blade 1, the flap blade 2 can further utilize the space of the pressure surface 101 of the main airfoil blade 1, improving the space utilization rate of the impeller assembly and increasing the lift of the impeller assembly without significantly increasing the space and weight occupied by the impeller assembly.
[0038] The embodiments of this application can use three sets of blades. Of course, the blades are not limited to three sets; they can also be two sets, four sets, or five sets, etc., which will not be listed here.
[0039] According to an embodiment of this application, the flap blade 2 is positioned at the tip 1c of the main blade. In this case, the flap blade 2 can better compensate for the low airflow utilization rate of the main blade 1 at the blade tip. The flap blade 2 can also reduce blade wear and damage. When the impeller assembly with the flap blade 2 is applied to a wind turbine, the service life of the wind turbine can be extended, the power generation and stability of the wind turbine can be improved, and the operating and maintenance costs can be reduced.
[0040] Here, "blade tip" refers to the area relative to the blade root, and there are no strict requirements regarding the blade height at the blade tip position. Of course, the flap blade 2 can also be positioned at the blade root or the middle of the blade to enhance the lift of the airflow at the corresponding locations.
[0041] According to embodiments of this application, the ratio of the blade height of the flap blade 2 to the blade height of the main blade 1 is 1 / 4 to 1 / 2. In this case, the size of the flap blade 2 will not be too large, thus avoiding a significant increase in the weight of the impeller assembly. Moreover, this size of flap blade 2 can maximize the lift in areas with weaker winds, thereby improving the working efficiency of the impeller assembly. For example, the ratio of the blade height of the flap blade 2 to the blade height of the main blade 1 is 1 / 3.
[0042] According to embodiments of this application, the gap between the main wing blade 1 and the flap blade 2 is 2mm-6mm to form a tandem arrangement of the blades, thereby increasing the lift of the impeller assembly and improving the wind energy conversion rate. Combined with... Figure 2 The gap here refers to the minimum distance L2 between the main wing blade 1 and the flap blade 2. In this case, the tandem arrangement of the main wing blade 1 and the flap blade 2 is significantly different from other tandem arrangements of winglets, and can ensure that the airflow passes through the main wing blade 1 and the flap blade 2 in sequence.
[0043] According to the embodiments of this application, in order to ensure structural stability and smooth airflow, the length of the first cascade chord line 10c (i.e., the first cascade chord length) of the main wing blade 1 gradually decreases from the blade root to the blade tip. Similarly, the length of the second cascade chord line 20c (i.e., the second cascade chord length) of the flap blade 2 can also gradually decrease from the blade root to the blade tip. Based on this, to balance good aerodynamic performance, structural strength, and low weight, the size of the flap blade 2 should not be too large. In the embodiments of this application, the relationship between the first cascade chord length of the main wing blade 1 and the second cascade chord length of the flap blade 2 at the same blade height satisfies: 1 / 4 × first cascade chord length ≤ second cascade chord length ≤ first cascade chord length.
[0044] To enhance aerodynamic performance away from the blade root, the ratio of the second cascade chord length to the first cascade chord length can be gradually increased along the direction from the blade root to the blade tip. Specifically, at the position where the first cascade chord length of the main airfoil 1 decreases sharply, the ratio of the second cascade chord length to the first cascade chord length of the flap blade 2 can reach 1 / 2, and even at the blade tip position, the second cascade chord length of the flap blade 2 can be equal to the first cascade chord length of the main airfoil 1.
[0045] According to an embodiment of this application, the main wing blade 1 and the flap blade 2 overlap along the circumferential portion of the hub 3, in combination. Figure 3The relationship between the width L1 of the overlapping portion and the chord length of the second blade cascade of the flap blade 2 satisfies: 0.25 × second blade cascade chord length ≤ L1 ≤ 0.5 × second blade cascade chord length. If the flap blade 2 and the main blade 1 are completely offset, the airflow exiting from the main blade 1 may form vortices or airflow separation at the trailing edge of the main blade. This application, by having at least partial overlap between the main blade 1 and the flap blade 2, can reduce mutual interference between blades, thereby improving wind energy capture efficiency. Furthermore, by dispersing the impact of wind force on the wind turbine as a whole, it helps reduce the vibration and swaying of the wind turbine under strong wind conditions. Further, this arrangement can also improve the fatigue resistance of the wind turbine and extend its service life. It also helps to improve the lift-to-drag ratio of the blades, enabling the wind turbine to generate greater torque and power at the same wind speed. When L1 is less than 0.25 × the second cascade chord length, the flap blade 2 has limited ability to adjust the airflow at the trailing edge 1b of the main wing blade. Therefore, L1 is chosen to be greater than or equal to 0.25 × the second cascade chord length. However, when L1 is greater than 0.5 × the second cascade chord length, the flap blade 2 causes unnecessary interference to the airflow at the leading edge of the main wing blade 1. Therefore, L1 is limited to ≤ 0.5 × the second cascade chord length. Of course, the possibility that L1 and the second cascade chord length conform to other functional relationships cannot be ruled out. Furthermore, the overlapping portion of the flap blade 2 ensures its installation strength on the main wing blade 1.
[0046] According to an embodiment of this application, the main airfoil blade 1 and the flap blade 2 partially overlap along the circumferential direction of the hub 3, and the ratio I of the width L1 of the overlapping portion and the second chord length of the flap blade 2 satisfies the following condition: the ratio I gradually decreases from the blade root to the blade tip. Since the size of the main airfoil blade 1 gradually decreases from the blade root to the blade tip, the less overlap there is between the flap blade 2 and the main airfoil blade 1 towards the blade tip, the more beneficial it is to increase the lift of the blade at the blade tip position.
[0047] According to an embodiment of this application, the angle between the blade chord line (i.e., at least one of the first blade chord line 10c and the second blade chord line 20c) and the vertical plane of the wind turbine axis is defined as the tilt angle. From the blade root to the blade tip, the tilt angle 10a of the first blade chord line generally shows a decreasing trend, decreasing from 30°~33° to 3°~5°, in order to reduce flow loss, increase lift coefficient, adapt to pressure gradient changes and improve structural strength.
[0048] According to an embodiment of this application, the tilt angle 10a of the first chord line of the main wing blade 1 is greater than the tilt angle 20a of the second chord line of the flap blade 2. This allows the flap blade 2 to more smoothly accelerate the airflow of the main wing blade 1, preventing excessive vibration and noise from the main wing blade 1. For example, the tilt angle 10a of the first chord line is 3° to 4° smaller than the tilt angle 20a of the second chord line.
[0049] According to an embodiment of this application, the main wing blade 1 and the flap blade 2 are connected by a bridging structure (see reference). Figure 4 The first bridging structure 4 and the second bridging structure 6 are shown in the diagram. These bridging structures enhance the structural strength of each set of blades. To prevent interference with airflow, the flap blades 2 can be connected to the main wing blades 1 at both ends. Alternatively, the possibility of connecting the flap blades 2 to the main wing blades 1 at other locations cannot be ruled out.
[0050] Of course, in addition to using a bridging structure to connect the main wing blade 1 and the flap blade 2, the main wing blade 1 and the flap blade 2 can also be an integrated design, including the case where the main wing blade 1 and the flap blade 2 are integrally formed, or the case where the main wing blade 1 and the flap blade 2 are integrally connected.
[0051] According to embodiments of this application, the impeller assembly is designed with low Reynolds number and high lift-to-drag ratio airfoils, and the cascade chord length and installation angle of each airfoil section are adapted to achieve the maximum wind energy utilization coefficient. It is worth noting that the blade shapes differ between wind turbines and fans. Fans, which need to propel airflow, use drag-type blades, while wind turbines, which need to allow airflow to pass smoothly, use lift-type blades.
[0052] According to an embodiment of this application, the leading edge 1a of the main wing blade extends in a straight line and is swept back with a sweep angle of 20°±5°. This swept-back blade reduces lateral flow at the blade leading edge, thereby reducing the pressure gradient at the blade leading edge and decreasing the generation and distortion of lateral vortices. Furthermore, the swept-back blade helps improve the aerodynamic efficiency of the blade, enabling the fan or compressor to operate more efficiently. Moreover, the swept-back blade can also reduce the tangential stress of the blade, which helps extend the blade's service life and reduce the frequency of maintenance and replacement.
[0053] Combination Figure 1 The leading edge 2a of the flap blade is curved, and the trailing edge 2bh of the flap blade is offset from the main blade 1. From the root of the flap blade to 55%-65% of the blade height, the leading edge 2a of the flap blade curves backward, and from 55%-65% of the blade height to the tip 2c of the flap blade, the leading edge 2a of the flap blade curves forward. Specifically, 60% of the blade height can be used as a dividing point: from the root to 60% of the blade height, the flap blade 2 curves backward, forming a backward-curving arc; from 60% of the blade height to the tip, the flap blade 2 curves forward. Here, "blade height" refers to the radial distance from the blade root to different radius sections of the blade.
[0054] According to an embodiment of this application, the chord length of the blade gradually decreases from the blade root to the blade tip. The blade here clearly includes the main airfoil blade 1 and the flap blade 2. That is, from the blade root to the blade tip, the length of the first chord length line 10c of the main airfoil blade 1 gradually decreases; and from the blade root to the blade tip, the length of the second chord length line 20c of the flap blade 2 gradually decreases.
[0055] Using the blade root chord length as a reference, to ensure smooth airflow, the chord length of the main wing blade tip 1c is reduced from the reference chord length to about half of it. Similarly, from the blade root to the blade tip, the blade chord length of the flap blade 2 can also be reduced from the reference chord length to about half of it.
[0056] According to the embodiments of this application, please refer to Figures 4 to 6 The impeller assembly also includes a collector 5, which is annularly mounted on the blades. There is a gap between the tip 1c of the main blade and the collector 5, and a gap between the tip 2c of the flap blade and the collector 5. Tests have shown that the flap blade 2, combined with the collector 5, provides a better acceleration effect. This is mainly because the first chord length of the blade tip 1c of the main blade is relatively short, making it unable to effectively utilize the tip airflow accelerated by the collector 5. The connection between the main blade 1 and the flap blade 2 increases the contact area with the collector 5, allowing the airflow accelerated by the collector 5 to act on the blade surface, significantly improving the wind turbine's wind energy utilization rate.
[0057] Specifically, the tip 1c of the main blade (i.e., the blade tip), especially the leading edge suction surface, is highly sensitive to the incoming flow. In this embodiment, the structure of the main blade 1 combined with the flap blade 2 broadens the adaptability of the blade tip to different incoming flows. The first chord length of the blade tip of the main blade 1 is relatively short, which cannot effectively utilize the blade tip airflow. However, the structure of the main blade 1 combined with the flap blade 2 increases the contact area between the blade and the collector 5, allowing the airflow accelerated by the collector 5 to act on the blade surface, significantly improving the wind energy utilization rate of the wind turbine.
[0058] The impeller assembly in this application embodiment, since each set of blades includes a main airfoil blade 1 and a flap blade 2, can therefore be called a tandem impeller. Based on experimental testing and analysis: the tandem impeller of this application embodiment... Figure 8 Compared to the prototype impeller, the wind energy utilization rate was increased by 10.5%, achieving the expected results.
[0059] Specifically, the experimental conditions were controlled as follows: incoming air velocity 6.5 m / s; both impellers were matched with the same collector for testing and verification; five anemometers were placed at fixed positions at the inlet, and air velocity (m / s) was collected at 1 min, 2 min, and 3 min, as follows:
[0061] Table 1. Test wind speed of prototype impeller
[0063] Table 2 Test wind speeds of tandem impellers The average wind speeds corresponding to the two impellers can be obtained from Tables 1 and 2, as shown in the following table:
[0064] Table 3 Comparison of key parameters between prototype impeller and tandem impeller Calculations using the wind energy utilization formula show that the tandem rotor improves wind energy utilization by 10.5% compared to the prototype rotor.
[0065] According to an embodiment of this application, a wind turbine is also provided; please refer to [link to relevant documentation]. Figure 7 It includes the body and the aforementioned impeller assembly, wherein the impeller assembly is mounted on the body.
[0066] According to the wind turbine of the present application embodiment, the main wing blade 1 and the flap blade 2 can generate lift one after the other under wind power. Compared with the single-blade impeller assembly, the impeller assembly of the wind turbine of the present application embodiment is easier to maintain the balance of the wind turbine in the working state.
[0067] It's worth noting that the energy conversion efficiency of a wind turbine depends on wind force and speed. To maximize wind speed, wind turbines use lift-type impellers. The design purpose of a lift-type impeller is to minimize air resistance, thus only using it to propel airflow; its driving force is minimal. Fans, on the other hand, need to propel airflow, so they use drag-type impellers. In other words, the impeller assemblies of wind turbines and fans are selected differently. Therefore, a wind turbine impeller assembly cannot be used as a fan impeller assembly.
[0068] Finally, it should be noted that the above embodiments are only for illustrating the present invention and not for limiting the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention and should be covered within the scope of the claims of the present invention.
Claims
1. An impeller assembly, characterized in that, include: Wheel hub; Multiple sets of blades are distributed on the outer periphery of the hub. Each set of blades includes a main wing blade and a flap blade. The main wing blade is connected to the hub. The flap blade is located on the side where the pressure surface of the main wing blade is located. The flap blade is connected to the main wing blade, and there is a gap between the main wing blade and the flap blade. The flap blade is located at the trailing edge of the main wing blade.
2. The impeller assembly according to claim 1, characterized in that, The flap blades are positioned at the tips of the main wing blades.
3. The impeller assembly according to claim 1, characterized in that, The ratio of the blade height of the flap blade to the blade height of the main wing blade is 1 / 4 to 1 / 2.
4. The impeller assembly according to claim 3, characterized in that, The ratio of the blade height of the flap blade to the blade height of the main wing blade is 1 / 3.
5. The impeller assembly according to claim 1, characterized in that, The gap is 2mm-6mm.
6. The impeller assembly according to claim 1, characterized in that, For the same blade height, the relationship between the first chord length of the main wing blade and the second chord length of the flap blade satisfies: 1 / 4 × first chord length ≤ second chord length ≤ first chord length.
7. The impeller assembly according to claim 1, characterized in that, The main wing blade and the flap blade overlap along the circumferential portion of the hub, and the relationship between the width L1 of the overlapping portion and the second chord length of the flap blade satisfies: 0.25 × second chord length ≤ L1 ≤ 0.5 × second chord length.
8. The impeller assembly according to claim 1, characterized in that, The main wing blade and the flap blade overlap circumferentially along the hub, and the ratio I of the width L1 of the overlapping portion and the second chord length of the flap blade satisfies the following: the ratio I gradually decreases from the blade root to the blade tip.
9. The impeller assembly according to any one of claims 1 to 8, characterized in that, The inclination angle of the first chord line of the main wing blade is greater than the inclination angle of the second chord line of the flap blade.
10. The impeller assembly according to any one of claims 1 to 8, characterized in that, The main wing blade and the flap blade are connected by a bridging structure.
11. The impeller assembly according to any one of claims 1 to 8, characterized in that, The leading edge of the main airfoil extends in a straight line and sweeps back at a sweep angle of 20°±5°. And / or, The leading edge of the flap blade is curved backward from the leaf root to 55%-65% of the leaf height, and then curved forward from 55%-65% of the leaf height to the leaf tip. And / or, From the leaf root to the leaf tip, the chord length of the blade gradually decreases.
12. The impeller assembly according to any one of claims 1 to 8, characterized in that, The impeller assembly also includes: A collector is arranged around the blade, and there is a gap between the tip of the main wing blade and the collector, and a gap between the tip of the flap blade and the collector.
13. A wind turbine, characterized in that, include: Organism; The impeller assembly according to any one of claims 1 to 12 is mounted on the machine body.