Rotor type, rotor blade and tilting rotorcraft

Abstract

The invention discloses a rotor wing type, a rotor wing blade and a tilt rotor aircraft, and particularly relates to the technical field of aircrafts, the ratio of the maximum thickness t of the rotor wing type to the chord length c of the wing type is t / c = 11.15%, and the position of the maximum thickness xt / c = 34.9%; the ratio of the maximum camber f of the wing type of the rotor to the chord length c of the wing type is f / c = 2.48%, and the position of the maximum camber b is xf / c = 22.7%; the wing section, located at the position 0.34 R-0. 9R away from the center of the propeller hub, of the propeller blade body is a rotor wing section, the wing section, located at the position R away from the center of the propeller hub, of the propeller blade body is an OA209 wing section, the rotor wing section is connected with the OA209 wing section through a transition wing section, and the OA209 wing section is connected with the sweepback section. According to the invention, more efficient aerodynamic performance and smoother mode conversion can be realized, and the overall flight performance is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft, and in particular to a rotor airfoil, a rotor blade and a tiltrotor aircraft. Background Art

[0002] Driven by the rapid development of aviation technology and diversified needs, tilt-rotor aircraft, as a new type of aircraft that combines the advantages of helicopter vertical take-off and landing with the high-speed flight of fixed-wing aircraft, has received widespread attention in recent years. When the tilt-rotor aircraft switches between helicopter mode and fixed-wing mode, the blades must withstand complex and changeable mechanical environments and airflow conditions, including but not limited to the huge centrifugal force generated by high-speed rotation, the sharp angle change during the mode conversion process, and the aerodynamic performance requirements at different flight speeds. These special conditions require the blades to not only have high strength and high durability, but also to be optimized in aerodynamic performance to ensure flight safety, improve energy efficiency and extend service life. Summary of the invention

[0003] The purpose of the present invention is to provide a rotor airfoil, a rotor blade and a tiltrotor aircraft to solve the problems existing in the above-mentioned prior art, to achieve more efficient aerodynamic performance and smoother mode conversion, and to improve the overall flight performance.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a rotor airfoil, comprising a leading edge, a trailing edge, and an upper camber and a lower camber located between the leading edge and the trailing edge, wherein the ratio of the maximum thickness t of the rotor airfoil to the chord length c of the airfoil is t / c=11.15%, and the position of the maximum thickness is x t / c=34.9%;The ratio of the maximum curvature f of the rotor airfoil to the chord length c of the airfoil is f / c=2.48%, and the position of the maximum curvature b is x f / c=22.7%;wherein, the upper arc is composed of the upper arc coordinate value pair x / c, y u / c, the lower arc is defined by the lower arc coordinate value pair x / c, y l / c, the upper arc coordinate value pair x / c, y u / c and the lower arc coordinate value pair x / c, y l / c are defined as follows:

[0006]

[0007]

[0008] Where x is the distance from the leading edge to the trailing edge along the chord line, and y is uis the distance between the upper arc and the chord, y l is the distance between the lower arc and the chord, and the coordinate value of the upper arc is x / c, y u / c and the lower arc coordinate value pair x / c, y l The maximum error of each of / c is equal to ±3%.

[0009] The present invention also provides a rotor blade, comprising a blade body, wherein the blade body comprises a first airfoil section, a second airfoil section, a transition airfoil section and a swept section, the maximum distance between the end of the second airfoil section and the center of the hub is R, the first airfoil section is at a distance of 0.34R-0.9R from the center of the hub, the first airfoil section is the rotor airfoil, the second airfoil section is at a distance of R from the center of the hub, the second airfoil section is an OA209 airfoil, the first airfoil section is connected to the second airfoil section through the transition airfoil, the transition airfoil is at a distance of 0.9RR from the center of the hub, and the second airfoil section is connected to the swept section.

[0010] Preferably, the blade body adopts a linear negative torsion design with a negative torsion angle of 35°, the torsion angle at the first position where the distance between the blade body and the center of the hub is 0R is 24.5°, the torsion angle at the second position where the distance between the blade body and the center of the hub is 0.34R is 12.6°; the torsion angle at the third position where the distance between the blade body and the center of the hub is 0.7R is 0°; the torsion angle at the fourth position where the distance between the blade body and the center of the hub is R is -10.5°.

[0011] Preferably, the blade body includes a skin and a beam, a trailing edge strip, a leading edge counterweight and a filling material arranged in the skin, the beam is arranged along the direction from the root to the tip of the blade body, the beam is arranged at the leading edge of the blade body, the leading edge counterweight is arranged in the beam, the leading edge counterweight is close to the leading edge side of the blade body, the trailing edge strip is fixedly installed at the trailing edge of the blade body, and the filling material can be evenly filled inside the skin.

[0012] Preferably, the blade root of the blade body is provided with two connection holes connected to the hub, and the two connection holes are provided with blade root bushings.

[0013] Preferably, the beam includes two root beams and a C-shaped beam, the root beam is sleeved outside the blade root bushing, the two root beams are fixedly connected to the C-shaped beam, and the outer wall of the C-shaped beam is tightly fitted with the inner wall of the skin at the leading edge of the blade body.

[0014] Preferably, the filling material includes a first filling material, a second filling material, a third filling material and a fourth filling material. The first filling material is filled between the C-shaped beam and the trailing edge strip, the gap between the root beam and the root bushing is filled with the second filling material, the gap between the two root beams and the gap between the root beam and the leading edge of the blade body are filled with the third filling material, and the gap between the two root beams and the inner side surface of the root end of the blade body is filled with the fourth filling material.

[0015] Preferably, the skin is paved with medium-temperature cured epoxy glass cloth prepreg, epoxy carbon cloth prepreg and epoxy unidirectional carbon cloth prepreg, and the beam is paved with medium-temperature cured epoxy glass coarse sand prepreg tape.

[0016] Preferably, the material of the leading edge counterweight is a tungsten-based high-density alloy, and the trailing edge strip is paved with epoxy glass coarse sand prepreg tape.

[0017] The present invention also provides a tiltrotor aircraft, comprising the rotor blades.

[0018] Compared with the prior art, the present invention has achieved the following technical effects:

[0019] The present invention provides a rotor airfoil, a rotor blade and a tiltrotor aircraft. The rotor airfoil improves lift characteristics and increases the lift-to-drag ratio of the airfoil. According to the different airflow velocities and pressure distributions at different parts of the rotor blade during rotation, the rotor blade combines the characteristics of the rotor airfoil and the OA209 airfoil, and the middle part is connected by a transition airfoil to form a mixed airfoil splicing structure to meet complex aerodynamic requirements and improve the efficiency and flight performance of the rotor. Compared with the existing straight blade, the swept section of the rotor blade can improve the working performance of the forward blade at a large Mach number and delay the appearance time of increased aerodynamic resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 Schematic diagram of parameters of the rotor airfoil of Example 1;

[0022] Figure 2 is a comparison diagram of the geometrical shapes of the rotor airfoil of Example 1 and the reference airfoil;

[0023] Figure 3is the polar curve of the rotor airfoil of Example 1 and the reference airfoil (Ma=0.5);

[0024] Figure 4 is an exploded view of the rotor blade of Example 2;

[0025] Figure 5 Schematic diagram of the spanwise twist distribution of the rotor blades of Example 2;

[0026] Figure 6 Schematic diagram of the rotor blade cross-section distribution of Example 2;

[0027] Figure 7 Schematic diagram of the cross section of rotor blade Z0 of Example 2;

[0028] Figure 8 is a schematic cross-sectional view of rotor blade Z64 of Example 2;

[0029] Fig. 9 is a schematic cross-sectional view of rotor blade Z100 of Example 2;

[0030] Fig.10 is a schematic cross-sectional view of rotor blade Z180 of Example 2;

[0031] Fig.11 is a schematic cross-sectional view of rotor blade Z250 of Example 2;

[0032] Fig.12 It is a cross-sectional schematic diagram of rotor blade Z380 of Example 2;

[0033] Fig.13 is a schematic cross-sectional view of rotor blade Z440 of Example 2;

[0034] Fig.14 This is a schematic cross-sectional view of rotor blade Z620 of Example 2.

[0035] In the figure: 1-upper wing skin; 2-blade root bushing; 3-second filling material; 4-third filling material; 5-first filling material; 6-C-shaped beam; 7-lower wing skin; 8-fourth filling material; 9-leading edge counterweight; 10-trailing edge strip; 11-root beam. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] The purpose of the present invention is to provide a rotor airfoil, a rotor blade and a tiltrotor aircraft to solve the problems existing in the above-mentioned prior art, to achieve more efficient aerodynamic performance and smoother mode conversion, and to improve the overall flight performance.

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Example 1

[0040] This embodiment provides a rotor airfoil, such as Figure 1-3 As shown, including the leading edge, the trailing edge, and the upper camber and the lower camber located between the leading edge and the trailing edge, the ratio of the maximum thickness t of the rotor airfoil to the chord length c of the airfoil is t / c=11.15%, and the position of the maximum thickness is x t / c=34.9%; the ratio of the maximum curvature f of the rotor airfoil to the chord length c of the airfoil is f / c=2.48%, and the position of the maximum curvature b is x f / c=22.7%; where the upper arc is the upper arc coordinate value pair x / c, y u / c, the lower arc is defined by the lower arc coordinate value pair x / c, y l / c, the upper arc coordinate value pair x / c, y u / c and the lower arc coordinate value pair x / c, y l / c are defined as follows:

[0041] x / c <![CDATA[y u / c]]> x / c <![CDATA[y l / c]]> 0 0 0 0 0.03141 0.03554 0.04128 -0.01908 0.07571 0.05645 0.08911 -0.02337 0.12315 0.06887 0.13708 -0.02567 0.17176 0.07545 0.18507 -0.02773 0.22074 0.07855 0.23305 -0.02975 0.26981 0.07981 0.28105 -0.03152 0.31890 0.08000 0.32906 -0.03280 0.36797 0.07936 0.37709 -0.03350 0.41703 0.07787 0.42511 -0.03363 0.46605 0.07536 0.47314 -0.03334 0.51500 0.07174 0.52117 -0.03277 0.56384 0.06695 0.56919 -0.03199 0.61256 0.06102 0.61722 -0.03096 0.66114 0.05399 0.66522 -0.02954 0.70956 0.04592 0.71320 -0.02751 0.75781 0.03697 0.76115 -0.02466 0.80595 0.02738 0.80903 -0.02085 0.85407 0.01769 0.85684 -0.01625 0.90234 0.00884 0.90460 -0.01118 0.95099 0.00231 0.95234 -0.00586 1 0 1 0

[0042] Where x is the distance from the leading edge to the trailing edge along the chord line, and y is the distance from the leading edge to the trailing edge along the chord line. u is the distance of the upper arc perpendicular to the chord, y l is the distance between the lower arc and the chord, and the coordinate value of the upper arc is x / c, y u / c and the lower arc coordinate value pair x / c, y l / c, the maximum error of each is equal to ±3%. The rotor airfoil of the present embodiment is an optimized airfoil obtained based on the OA212 airfoil by combining the airfoil aerodynamic numerical simulation method, the Kriging model and the airfoil aerodynamic shape optimization method constructed by the genetic algorithm. The Mach number Ma=0.5, and the lift coefficient is ensured not to decrease, so that the rotor airfoil of the present embodiment is compared with the reference airfoil at the angle of attack of 3.58° and 10°, respectively, and the drag coefficient is reduced by 12.5% ​​and 0.84% ​​respectively; when the drag coefficient is the same, the rotor airfoil of the present embodiment can produce a larger lift coefficient.

[0043] Example 2

[0044] This embodiment provides a rotor blade, such as Figure 4-14 As shown, it includes a blade body, the blade body includes a first airfoil section, a second airfoil section, a transition airfoil section and a swept section, the maximum distance R between the end of the second airfoil section and the center of the hub, the first airfoil section is at a distance of 0.34R-0.9R from the center of the hub, the first airfoil section is the rotor airfoil of Example 1, the second airfoil section is at a distance of R from the center of the hub, the second airfoil section is an OA209 airfoil, the first airfoil section is connected to the second airfoil section through a transition airfoil, the transition airfoil is at a distance of 0.9RR from the center of the hub, and the second airfoil section is connected to the swept section. The maximum distance R between the end of the second airfoil section of the rotor blade of this embodiment and the center of the hub is 0.9m, and the actual length from the first airfoil section to the second airfoil section is 0.694m.

[0045] It is further preferred in the implementation manner of the present embodiment that the blade body adopts a linear negative torsion design, the negative torsion angle is 35°, the torsion angle at the first position where the distance between the blade body and the center of the hub is 0R is 24.5°, the torsion angle at the second position where the distance between the blade body and the center of the hub is 0.34R is 12.6°; the torsion angle at the third position where the distance between the blade body and the center of the hub is 0.7R is 0°; the torsion angle at the fourth position where the distance between the blade body and the center of the hub is R is -10.5°, and there is a linear transition between the first position and the second position, a linear transition between the second position and the third position, and a linear transition between the third position and the fourth position.

[0046] It is further preferred in the implementation of this embodiment that the blade body includes a skin and a beam, a trailing edge strip 10, a leading edge counterweight 9 and a filling material arranged in the skin, the beam is arranged along the direction from the root to the tip of the blade body, the beam is arranged at the leading edge of the blade body, a leading edge counterweight 9 is arranged in the beam, the leading edge counterweight 9 is close to the leading edge side of the blade body, the trailing edge strip 10 is fixedly installed at the trailing edge of the blade body, and the trailing edge strip 10 is tightly fitted with the inner side wall of the skin at the trailing edge of the blade body, and the filling material can be evenly filled inside the skin. The skin includes an upper wing skin 1 and a lower wing skin 7, the upper wing skin 1 and the lower wing skin 7 are closed to form the outer shape of the blade body, and the filling material inside the skin supports the skin. The skin itself constitutes a torsion-resistant box-shaped part, providing torsional stiffness of the blade section. The upper wing skin 1 and the lower wing skin 7 are laid at the root of the blade to strengthen the root, and the thickness decreases in the span direction, and 3 layers are laid at the tip of the blade. The inner side uses unidirectional carbon cloth prepreg 0° and carbon cloth prepreg ±45° ply, and the outer surface has a layer of glass cloth prepreg 0° ply to protect the carbon cloth skin and obtain a high outer surface roughness. The leading edge counterweight 9 is used to adjust the chord-wise center of gravity of the blade. The trailing edge strip 10 is used to adjust the profile swing stiffness.

[0047] In the implementation of this embodiment, it is further preferred that the blade root of the blade body is provided with two connection holes connected to the hub, and the two connection holes are provided with blade root bushings. The blade root bushing 2 is used to connect the blade pin on the hub, and the blade root bushing 2 is made of stainless steel, and its outer surface is the surface to be glued.

[0048] It is further preferred in the implementation of this embodiment that the beam includes two root beams 11 and a C-shaped beam 6, the root beam 11 is sleeved outside the blade root bushing 2, the two root beams 11 are fixedly connected to the C-shaped beam 6, and the outer wall of the C-shaped beam 6 is tightly fitted with the inner wall of the skin of the leading edge of the blade body. The root beam 11 is the wrapped part of the beam at the blade root, which is used to fix the blade root bushing 2 and transmit part of the centrifugal force; the C-shaped beam 6 can withstand large rotational centrifugal force, flapping bending moment and swing bending moment, so that the blade body can withstand a large rotation speed. Furthermore, the root beam 11 and the C-shaped beam 6 are integrally formed.

[0049] It is further preferred in the implementation of this embodiment that the filling material includes a first filling material 5, a second filling material 3, a third filling material 4 and a fourth filling material 8, the first filling material 5 is filled between the C-shaped beam 6 and the trailing edge strip 10, the gap between the root beam 11 and the blade root bushing 2 is filled with the second filling material 3, the gap between the two root beams 11 and the gap between the root beam 11 and the leading edge of the blade body is filled with the third filling material 4, and the gap between the two root beams 11 and the inner side surface of the root end of the blade body is filled with the fourth filling material 8. The first filling material 5 is PMI foam, which is close to the inner side of the C-shaped beam 6 and the upper wing skin 1 and the lower wing skin 7, supporting the skin and providing partial torsional stiffness to the section. The second filling material 3 is used to fill the gap between the root beam 11 and the blade root bushing 2, so that the parts at the root of the blade are connected more tightly and the direction of the beam is maintained. The fourth filling material 8 is formed by curing a chopped fiber mixture and wraps the two root beams 11 at the end of the blade root. The blade body adopts a modular design, that is, the blade body is decomposed into multiple parts that are easy to disassemble and replace. Each part is replaceable, which reduces maintenance costs and time and improves the operability and efficiency of maintenance.

[0050] In the implementation of this embodiment, it is further preferred that the skin is laid by medium temperature cured epoxy glass cloth prepreg, epoxy carbon cloth prepreg and epoxy unidirectional carbon cloth prepreg, and the beam is laid by medium temperature cured epoxy glass coarse sand prepreg. The C-shaped beam 6 provides 75% to 80% of the flapping stiffness and 30% to 40% of the swing stiffness of the blade body, making full use of the excellent longitudinal tensile strength and fatigue strength of the composite material, and can meet the load-bearing design requirements of the centrifugal force load and the flapping load of the blade body.

[0051] It is further preferred in the implementation manner of this embodiment that the material of the leading edge counterweight 9 is a tungsten-based high-density alloy, and the trailing edge strip 10 is paved with epoxy glass coarse sand prepreg tape.

[0052] Example 3

[0053] This embodiment provides a tiltrotor aircraft, including the rotor blades of Embodiment 2.

[0054] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A rotor airfoil, characterized in that: The rotor airfoil includes a leading edge, a trailing edge, and an upper camber and a lower camber located between the leading edge and the trailing edge. The ratio of the maximum thickness t of the rotor airfoil to the chord length c of the airfoil is t / c=11.15%. The position of the maximum thickness is x t / c=34.9%;The ratio of the maximum curvature f of the rotor airfoil to the chord length c of the airfoil is f / c=2.48%, and the position of the maximum curvature b is x f / c=22.7%;wherein, the upper arc is composed of the upper arc coordinate value pair x / c, y u / c, the lower arc is defined by the lower arc coordinate value pair x / c, y l / c, the upper arc coordinate value pair x / c, y u / c and the lower arc coordinate value pair x / c, y l / c are defined as follows: Where x is the distance from the leading edge to the trailing edge along the chord line, and y is u is the distance between the upper arc and the chord, y l is the distance between the lower arc and the chord, and the coordinate value of the upper arc is x / c, y u / c and the lower arc coordinate value pair x / c, y l The maximum error of each of / c is equal to ±3%.

2. A rotor blade, characterized in that: The invention comprises a blade body, wherein the blade body comprises a first airfoil section, a second airfoil section, a transition airfoil section and a swept section, wherein the maximum distance between the end of the second airfoil section and the center of the hub is R, the first airfoil section is at a distance of 0.34R-0.9R from the center of the hub, the first airfoil section is the rotor airfoil according to claim 1, the second airfoil section is at a distance of R from the center of the hub, the second airfoil section is an OA209 airfoil, the first airfoil section is connected to the second airfoil section through the transition airfoil, the transition airfoil is at a distance of 0.9RR from the center of the hub, and the second airfoil section is connected to the swept section.

3. The rotor blade according to claim 2, characterized in that: The blade body adopts a linear negative torsion design with a negative torsion angle of 35°. The torsion angle at the first position where the distance between the blade body and the center of the hub is 0R is 24.5°; the torsion angle at the second position where the distance between the blade body and the center of the hub is 0.34R is 12.6°; the torsion angle at the third position where the distance between the blade body and the center of the hub is 0.7R is 0°; the torsion angle at the fourth position where the distance between the blade body and the center of the hub is R is -10.5°.

4. The rotor blade according to claim 2, characterized in that: The blade body includes a skin and a beam, a trailing edge strip, a leading edge counterweight and a filling material arranged in the skin. The beam is arranged along the direction from the root to the tip of the blade body. The beam is arranged at the leading edge of the blade body. The leading edge counterweight is arranged in the beam. The leading edge counterweight is close to the leading edge side of the blade body. The trailing edge strip is fixedly installed at the trailing edge of the blade body. The filling material can be evenly filled inside the skin.

5. The rotor blade according to claim 4, characterized in that: The blade root of the blade body is provided with two connection holes connected to the hub, and the two connection holes are provided with blade root bushings.

6. The rotor blade according to claim 5, characterized in that: The beam includes two root beams and a C-shaped beam. The root beam is sleeved outside the blade root bushing. The two root beams are fixedly connected to the C-shaped beam. The outer wall of the C-shaped beam fits tightly with the inner wall of the skin at the leading edge of the blade body.

7. The rotor blade according to claim 6, characterized in that: The filling material includes a first filling material, a second filling material, a third filling material and a fourth filling material. The first filling material is filled between the C-shaped beam and the trailing edge strip, the gap between the root beam and the root bushing is filled with the second filling material, the gap between the two root beams and the gap between the root beam and the leading edge of the blade body are filled with the third filling material, and the gap between the two root beams and the inner side surface of the root end of the blade body is filled with the fourth filling material.

8. The rotor blade according to claim 4, characterized in that: The skin is formed by laying medium-temperature cured epoxy glass cloth prepreg, epoxy carbon cloth prepreg and epoxy unidirectional carbon cloth prepreg, and the beam is formed by laying medium-temperature cured epoxy glass coarse sand prepreg tape.

9. The rotor blade according to claim 4, characterized in that: The material of the leading edge counterweight is a tungsten-based high-density alloy, and the trailing edge strip is paved with epoxy glass coarse sand prepreg tape.

10. A tiltrotor aircraft, characterized in that: The invention comprises the rotor blade according to any one of claims 2 to 9.

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