Novel helicopter blade structure with winglet

Abstract

The invention belongs to the technical field of pneumatic design of helicopter rotors, and relates to a novel helicopter blade structure with winglets. According to the rotor blade adopting the novel winglet, the aerodynamic noise of a rotor can be reduced, a good noise reduction effect is achieved, and the aerodynamic performance of the rotor can be improved. Each paddle is composed of a main body section and a winglet section, the main body section adopts a symmetrical airfoil profile and a rectangular appearance, the radius of the main body section is R, the chord length of the main body section is C, C is 0.1 R-0. 125R, linear pneumatic negative torsion design is adopted, and the torsion rate T is-8 degrees / R-10 degrees / R; the winglet section comprises two winglets which are arranged on the outermost side of the main body section in tandem; and the chord direction of the root of the winglet is consistent with the chord direction of the section of the outermost side of the main body section.

Description

Technical Field

[0001] This invention belongs to the field of helicopter rotor aerodynamic design technology, and relates to a novel helicopter rotor blade structure with winglets. Background Technology

[0002] As the lifting, propulsion, and control surfaces of a helicopter, the rotor's performance directly determines the helicopter's flight performance, making it a core and critical component. The aerodynamic performance parameters of the rotor mainly include noise level, hovering performance, and forward flight efficiency, with the aerodynamic shape of the rotor blades directly determining its aerodynamic performance. Typically, the aerodynamic layout parameters of the rotor, such as tip shape, chord distribution, airfoil configuration, and torsional distribution, are optimized and combined to create a blade shape scheme that meets aerodynamic performance requirements. In addition, research has shown that adding winglets to the blade tips can improve the rotor's aerodynamic performance, especially its noise characteristics. The mechanism involves the winglet generating a secondary vortex that interferes with the tip vortex generated by the main rotor, thus dissipating the tip vortex before it causes blade-vortex interference, thereby reducing the blade-vortex interference noise that significantly affects the user.

[0003] While winglet design can reduce rotor noise, it often results in other performance losses, such as hovering efficiency. Summary of the Invention

[0004] Purpose of the invention: To provide a novel helicopter rotor blade structure with winglets, which can not only reduce rotor aerodynamic noise and achieve better noise reduction effect, but also improve rotor aerodynamic performance.

[0005] The technical solution is as follows: A novel helicopter rotor blade structure with winglets, wherein the rotor blade is composed of a main body section and a winglet section, wherein the main body section adopts a symmetrical airfoil with a rectangular shape and a radius of R, and the chord length of the main body section is C, where C is 0.1R to 0.125R, and adopts a linear aerodynamic negative torsion design with a torsion rate T of -8° / R to -10° / R; The winglet section consists of two winglets, arranged one in front of the other on the outermost side of the main body section; the chord direction at the root of the winglet is consistent with the chord direction of the outermost section of the main body section. Preferably, the chord length C is 0.11R and the torsion ratio T is -8.5° / R.

[0006] The distance from the center of the leading edge circle to the leading edge point is V3, the radius is V1, and the azimuth is V2. V1 is 0 to 0.025°, V2 is 0 to 2°, and V3 is 0.01 to 0.035°. The azimuth angle V2 is the angle between the line connecting the leading edge of the forewinglet and the center of the leading edge circle and the chord.

[0007] Preferably, V1 is 0.0225°C, V2 is 1 / 3, and V3 is 0.0295°C. The distance V4 between the axis of the rear winglet and the axis of the fore winglet is 0.3 to 0.6C; the distance V5 in the thickness direction is -0.03 to 0.03C. The negative sign indicates that the rear winglet is above the fore winglet. The axis is a quarter-chord line.

[0008] Preferably, V4 is set at 0.4°C and V5 at 0.015°C. The blade winglets adopt the same symmetrical airfoil as the main blade section, with no twist design.

[0009] The blade winglet 1 has a chord length C1 of 0.2–0.3C and a span L1 of 0.4–0.6C; the winglet 2 has a chord length C2 of 0.3–0.4C and a span L2 of 0.5–0.7C.

[0010] Preferably, C1 is 0.3C, L1 is 0.6C, C2 is 0.4C, and L2 is 0.7C; The blade winglets are designed with an up-and-down reversible shape to reduce interference between the winglets and increase the dissipation of vortices at the blade tip.

[0011] The forewinglet is anhedral, and the rearwinglet is anhedral. The anhedral angle is θ1, which is 10° to 30°; the anhedral angle is θ2, which is 10° to 30°.

[0012] The forewinglet is dihedral, and the rear winglet is anhedral, with θ1 ranging from 10° to 30°; the dihedral angle is θ2, which also ranges from 10° to 30°.

[0013] Preferably, θ1 is 10° and θ2 is 20°; The blade winglets adopt a parabolic swept-back design to reduce the adverse effects of shock waves on the rotor aerodynamic flow field and noise.

[0014] In summary, the beneficial effects of the present invention are as follows: The aerodynamic shape of the propeller provided by this invention consists of a main body section and winglet sections. The winglet sections adopt a double-winglet combination design, which can improve the aerodynamic performance of the rotor while reducing rotor aerodynamic noise. High-precision numerical simulation results, such as… Figure 4 and Figure 5 As can be seen, compared with the original rotor without winglets, the rotor with winglets provided by the present invention has improved aerodynamic performance and significantly reduced rotor aerodynamic noise in the mid-to-high frequency band where propeller-vortex interference noise is concentrated. Attached Figure Description

[0015] Figure 1This is a schematic diagram of the cross-sectional position parameters of the airfoil tip of the propeller implementing the present invention; Figure 2 This is a schematic diagram of the blade shape for implementing the present invention; Figure 3 This is a partial isovorbital diagram of the rotor tip winglet implementing the present invention; Figure 4 This is a comparison of the aerodynamic performance of the winglet rotor implementing the present invention with that of the original rotor; Figure 5 This is a comparison of the noise sound pressure level of the winglet rotor implementing the present invention with that of the original rotor. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0017] A novel helicopter rotor blade structure with winglets. The blade consists of a main body section and winglets. The main body section adopts a symmetrical airfoil with a rectangular shape and a radius of R. The chord length of the blade section is C, which is 0.1R to 0.125R. It employs a linear aerodynamic negative torsion design with a torsion rate T of -8° / R to -10° / R. Preferably, the chord length C is 0.11R and the torsion rate T is -8.5° / R. The winglets consist of two winglets, and the chord direction of the winglets is consistent with the chord direction of the blade tip section. The position of the winglet 1 near the leading edge of the blade is determined by the leading edge circular parameters of the airfoil, including the circular radius V1, azimuth angle V2, and distance from the center of the circle to the leading edge point V3. V1 is 0 to 0.025C, and V2 is 0 to 2... V3 is 0.01 to 0.035°C. Figure 1 A schematic diagram of the airfoil section position parameters is provided. Preferably, V1 is 0.0225C, and V2 is 1 / 3. V3 takes 0.0295C.

[0018] The axial distance of the blade winglet 2 relative to the chordal axis of the winglet 1 is V4, where V4 is 0.3–0.6C; the thickness distance is V5, where V5 is -0.03–0.03C. The negative sign indicates that the winglet 2 is above the winglet 1. Preferably, V4 is 0.4C and V5 is 0.015C. The blade winglet adopts the same symmetrical airfoil as the main blade section, without torsion. The chord length C1 of the winglet 1 is 0.2–0.3C, and the span L1 is 0.4–0.6C; the chord length C2 of the winglet 2 is 0.3–0.4C, and the span L2 is 0.5–0.7C. Preferably, C1 is 0.3C, L1 is 0.6C, C2 is 0.4C, and L2 is 0.7C. The blade winglets employ an anhedral design to reduce interference between winglets and increase dissipation of vortices at the blade tip. Winglet 1 has an anhedral angle θ1, ranging from 10° to 30°; winglet 2 has a dihedral angle θ2, also ranging from 10° to 30°. Preferably, θ1 is 10° and θ2 is 20°.

[0019] The blade winglets adopt a parabolic swept-back design to reduce the adverse effects of shock waves on the rotor aerodynamic flow field and noise.

[0020] Example Figure 2 A top view and a cross-sectional view of the aerodynamic shape of the blades in a preferred embodiment are provided.

[0021] Figure 3 The present invention provides a partial isovordination diagram of the rotor tip winglets. It can be seen that the front and rear winglets each generate a secondary vortex, which interferes with and mixes with the tip vortex generated by the main body section.

[0022] Figure 4 A comparison of the aerodynamic performance of the rotor with the winglet of the present invention and the original rotor is given. It can be seen that the aerodynamic performance of the rotor is improved after adding the winglet.

[0023] Figure 5 A comparison of the noise sound pressure level of the rotor with the winglet of the present invention and the original rotor is given. It can be seen that the noise value of the rotor is reduced after adding the winglet.

[0024] Obviously, the embodiments described in the specific implementation details of this application are merely for the purpose of more clearly explaining the technical solutions in the specification, and are only a part of the embodiments of this application, and are not intended to limit this application. All other embodiments obtained by those skilled in the art based on the embodiments in the specific implementation details without creative effort should fall within the protection scope of this application.

Claims

1. A novel helicopter rotor blade structure with winglets, characterized in that: The blade consists of a main body section and winglet sections. The main body section adopts a symmetrical airfoil with a rectangular shape and a radius of R. The chord length of the main body section is C, which is 0.1R to 0.125R. It adopts a linear aerodynamic negative torsion design with a torsion rate T of -8° / R to -10° / R. The winglet section includes two winglets, one in front of the other on the outermost side of the main body section; the chord direction at the root of the winglet is consistent with the chord direction of the outermost section of the main body section.

2. The novel helicopter rotor blade structure with winglets according to claim 1, characterized in that: The chord length C is taken as 0.11R, and the torsion ratio T is taken as -8.5° / R.

3. The novel helicopter rotor blade structure with winglets according to claim 2, characterized in that: The position of the leading winglet near the leading edge of the blade is determined by the leading edge circularity parameter of the airfoil; The distance from the center of the leading edge circle to the leading edge point is V3, the radius is V1, and the azimuth is V2. V1 is 0 to 0.025°, V2 is 0 to 2°, and V3 is 0.01 to 0.035°. The azimuth angle V2 is the angle between the line connecting the leading edge of the forewinglet and the center of the leading edge circle and the chord.

4. The novel helicopter rotor blade structure with winglets according to claim 3, characterized in that: The distance V4 between the axis of the rear winglet and the axis of the fore winglet is 0.3 to 0.6C; the distance V5 in the thickness direction is -0.03 to 0.03C. The negative sign indicates that the rear winglet is above the fore winglet. The axis is a quarter-chord line.

5. A novel helicopter rotor blade structure with winglets according to claim 4, characterized in that: The blade winglets adopt the same symmetrical airfoil as the main blade section, with no twist design.

6. A novel helicopter rotor blade structure with winglets according to claim 5, characterized in that: The chord length of the forewinglet is C1, which is 0.2–0.3C, and the span is L1, which is 0.4–0.6C; the chord length of the aft winglet is C2, which is 0.3–0.4C, and the span is L2, which is 0.5–0.7C.

7. A novel helicopter rotor blade structure with winglets according to claim 6, characterized in that: The blade winglets are designed with an up-and-down reversible shape.

8. A novel helicopter rotor blade structure with winglets according to claim 7, characterized in that: The forewinglet is anhedral, and the rearwinglet is anhedral. The anhedral angle is θ1, which is 10° to 30°; the anhedral angle is θ2, which is 10° to 30°.

9. A novel helicopter rotor blade structure with winglets according to claim 7, characterized in that: The forewinglet is dihedral, and the rear winglet is anhedral, with θ1 ranging from 10° to 30°; the dihedral angle is θ2, which also ranges from 10° to 30°.

10. A novel helicopter rotor blade structure with winglets according to claim 7, characterized in that: The blade winglets are designed with a parabolic sweepback.

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