Open-rotor blade, open-rotor, and open-rotor engine

Abstract

The application provides an open rotor blade, an open rotor and an open rotor engine, and relates to the field of aero-engines.The open rotor blade comprises a leading edge, a trailing edge, a blade tip and a blade root.The leading edge is swept back as a whole, and the axial dimension of the leading edge at the blade tip is greater than the axial dimension of the leading edge at the blade root.The trailing edge is swept back as a whole, and the axial dimension of the trailing edge at the blade tip is greater than the axial dimension of the trailing edge at the blade root.The blade root has a maximum camber angle, the camber angle at 60%±10% of the blade height is less than the maximum camber angle, and the blade tip has a minimum camber angle, and the angle range of the minimum camber angle is 1°-8°, so as to reduce shock loss.

Description

Technical Field

[0001] This invention relates to the field of aero-engines, and more particularly to open rotor blades, open rotors, and open rotor engines. Background Technology

[0002] Continuous advancements in aircraft propulsion system technology are essential for achieving energy conservation and emission reduction in the air transport industry. Improvements in aero-engine performance are achieved by increasing engine thermal efficiency and propulsive efficiency. Thermal efficiency is improved by increasing turbine inlet temperature, overall engine pressure ratio, and component efficiency; however, these three factors are already at relatively high levels, limiting further improvements. Propulsive efficiency is primarily improved by increasing the bypass ratio. However, for traditional turbofan engines, increasing the bypass ratio inevitably leads to an increase in nacelle diameter, resulting in increased weight and aerodynamic drag, thus restricting further increases in bypass ratio. Open rotor engines, with their non-enclosed casing, are not constrained by it and can achieve ultra-high bypass ratios (e.g., 30-90), significantly improving propulsive efficiency. Their fuel consumption can be reduced by 15%-20% or more compared to currently in-service advanced aero-engines. The application of open rotor engines is one of the important pathways to achieving green aviation.

[0003] The open fan is the core propulsion component of an open rotary engine, and its performance has a crucial impact on the engine's fuel consumption rate. The main thrust-generating component of an open fan is the rotor blades, which are connected to the hub and rotate around the fan shaft, pressurizing the airflow and generating axial and circumferential motion. In modern civil aircraft, under the demands of flight speed and thrust, the rotor blades typically operate under high subsonic airflow conditions. The airflow is further accelerated at the blade suction surface, reaching supersonic speeds, forming shock waves on the blade surface, causing significant energy loss and leading to a decrease in engine propulsion efficiency. Reducing shock wave losses is one of the important means to improve the aerodynamic efficiency of open fans. Summary of the Invention

[0004] The purpose of this invention is at least to provide an open rotor blade, an open rotor, and an open rotor engine to reduce shock wave losses.

[0005] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.

[0006] One embodiment of the present invention provides an open rotor blade, which includes a leading edge, a trailing edge, a blade tip, and a blade root.

[0007] The leading edge sweeps backward as a whole, and the axial dimension of the leading edge at the leaf tip is greater than the axial dimension of the leading edge at the leaf root.

[0008] The trailing edge sweeps backward as a whole, and the axial dimension of the trailing edge at the leaf tip is greater than that at the leaf root.

[0009] The leaf root has the largest leaf bend angle, the leaf bend angle at 60%±10% of the leaf height is smaller than the largest leaf bend angle, and the leaf tip has the smallest leaf bend angle, with the angle range of the smallest leaf bend angle being 1°~8°.

[0010] In some embodiments, the meridional projection of the leading edge is represented by the coordinate point (x1, r1), where x1 is the axial coordinate, r1 is the radial coordinate, and (x1, r1) satisfies x1 = f1(r1), where f1(r1) is a cubic polynomial.

[0011] In some embodiments, f1(r1) has one and only one minimum value, corresponding to the coordinate point (x... 1，min r 1，min ), (x 1，min r 1，min It is located in the middle of the projection of the leading edge onto the meridional plane.

[0012] In some embodiments, the coordinates of the leaf root on the meridional projection of the leading edge are (x... 1，hub r 1，hub The coordinates of the leaf tip on the meridional projection of the leading edge are (x... 1，tip r 1，tip ), where r 1，min r 1，hub With r 1，tip Satisfying 0.4 < (r) 1，min -r 1，hub ) / (r 1，tip -r 1，hub <0.6.

[0013] In some embodiments, the projection of the trailing edge onto the meridional plane is represented by the coordinate point (x2, r2), where x2 is the axial coordinate, r2 is the radial coordinate, and (x2, r2) satisfies x2 = f2(r2), where f2(r2) is a cubic polynomial.

[0014] In some embodiments, f2(r2) has one and only one minimum value, corresponding to the coordinate point (x... 2，min r 2，min ), (x 2，min r 2，min It is positioned closer to the leaf root than the leaf tip.

[0015] In some embodiments, the coordinates of the leaf root on the meridional projection of the trailing edge are (x... 2，hub r2，hub The coordinates of the tip of the blade on the meridional projection of the trailing edge are (x... 2，tip r 2，tip ), where r 2，min r 2，hub With r 2，tip Satisfying 0.2 < (r) 1，min -r 1，hub ) / (r 1，tip -r 1，hub <0.4.

[0016] In some embodiments, the angle of attack at the leaf root ranges from 0° to 2°, the angle of attack at 50% ± 5% of the leaf height ranges from -4° to -2°, and the angle of attack at the leaf tip ranges from -12° to -6°.

[0017] In some embodiments, at the leaf root, the bend angle at 30%~40% of the leaf chord length ranges from 20%±5% leaf bend angle, the bend angle at 50%~60% of the leaf chord length ranges from 50%±5% leaf bend angle, and the bend angle at 70%~80% of the leaf chord length ranges from 80%±5% leaf bend angle.

[0018] In some embodiments, at 50%±10% of the leaf height, the bend angle at 5%~15% of the leaf chord length ranges from 20%±5% of the leaf bend angle, the bend angle at 65%~75% of the leaf chord length ranges from 50%±5% of the leaf bend angle, and the bend angle at 85%~95% of the leaf chord length ranges from 80%±5% of the leaf bend angle.

[0019] In some embodiments, at the leaf tip, the bend angle at 5%~15% of the leaf chord length ranges from 20%±5% leaf bend angle, the bend angle at 30%~40% of the leaf chord length ranges from 50%±5% leaf bend angle, and the bend angle at 80%~90% of the leaf chord length ranges from 80%±5% leaf bend angle.

[0020] In some embodiments, the leaf has a maximum leaf thickness position in the leaf thickness distribution, which is located at 20% to 35% of the leaf chord length.

[0021] One embodiment of the present invention provides an open rotor, including a hub and rotor blades as described in the above embodiments.

[0022] One embodiment of the present invention provides an open rotor engine, including rotor blades as described in the above embodiments, or including an open rotor as described in the above embodiments.

[0023] The open rotor blades involved in this invention reduce or even eliminate shock waves on the blade surface by improving the structural shape of the blade itself, including the leading edge shape, trailing edge shape, and the distribution of blade bend angle, so that the open fan can work efficiently at the design point and the open rotor or open rotor engine can obtain higher propulsion efficiency. Attached Figure Description

[0024] The above-described features and advantages of the present invention will be better understood after reading the following detailed description of embodiments of the present disclosure in conjunction with the accompanying drawings. In the drawings, components are not necessarily drawn to scale, and components having similar related properties or features may have the same or similar reference numerals. Wherein:

[0025] Figure 1 This is a schematic diagram of rotor blades according to some embodiments;

[0026] Figure 2 This is a side view of the rotor blades according to some embodiments;

[0027] Figure 3 This is a schematic diagram of the meridional projection of the leading and trailing edges according to some embodiments;

[0028] Figure 4 It is a distribution curve of leading edge airflow angle, leading edge metal angle and angle of attack according to some embodiments;

[0029] Figure 5 It is a distribution curve diagram of leading edge metal angle, trailing edge metal angle and airfoil bend angle according to some embodiments;

[0030] Figure 6 It is a curve diagram showing the distribution of the bend angle at the leaf root, leaf middle and leaf tip, based on some embodiments;

[0031] Figure 7 This is a leaf thickness distribution curve diagram based on some embodiments;

[0032] Figure 8 This is a circumferential offset distribution curve diagram based on some embodiments;

[0033] Figure 9 This is a comparison chart of isentropic Mach number distributions based on some embodiments. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the aspects described below with reference to the accompanying drawings and specific embodiments are merely exemplary and should not be construed as limiting the scope of protection of the present invention in any way.

[0035] It should be understood that the terms “system,” “device,” “unit,” and / or “module” used herein are one method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other words can achieve the same purpose, they may be replaced by other expressions.

[0036] It is understood that the technical terms that may be used in the description of this specification, such as “center,” “longitudinal,” “lateral,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” 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 implementation method 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 limiting the scope of protection of the invention.

[0037] It should be noted that the use of terms such as "first" and "second" to define features in this document is merely for the purpose of distinguishing the corresponding features. Unless otherwise stated, these terms have no special meaning and should not be construed as limiting the scope of protection of this invention. As shown in this specification and claims, the terms "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural, unless the context clearly indicates otherwise. Generally, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, and these steps and elements do not constitute an exclusive list; the method or apparatus may also include other steps or elements.

[0038] In the description of this specification, it should also be noted that, unless otherwise expressly specified or limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, an integral connection, or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium, or a connection within two components, etc. Those skilled in the art can understand the specific meaning of the above terms in this specification according to the specific circumstances.

[0039] This specification provides an embodiment of an open rotor engine, including an open fan (also known as an open rotor). The open fan is the core propulsion component of the open rotor engine, and its performance has a crucial impact on the fuel consumption rate of the open rotor engine. The main thrust-generating component of the open fan is the rotor blades. The rotor blades are connected to the hub and rotate around the fan shaft, which can pressurize the airflow and generate axial and circumferential motion. This specification provides an embodiment of an open rotor blade, involving its shape and structural design, which can reduce the shock waves generated on the blade surface, or even eliminate the generation of shock waves on the blade surface, so that the open rotor engine can achieve higher propulsion efficiency. The shape and structural design of the open rotor blade will be described below with reference to the accompanying drawings.

[0040] Figure 1 This is a schematic diagram of rotor blades according to some embodiments; Figure 2 This is a side view of the rotor blades according to some embodiments.

[0041] This specification provides an example of an open rotor blade 100, such as... Figure 1 and Figure 2 As shown, the open rotor blade 100 includes a leading edge 110, a trailing edge 120, a blade tip 130, and a blade root 140.

[0042] The leading edge 110 and the trailing edge 120 are both swept back. The axial dimension of the leading edge at the blade tip is larger than that at the blade root, and the axial dimension of the trailing edge at the blade tip is larger than that at the blade root. In this specification, "axial" refers to the axial direction of the open rotor or engine, with the fan shaft extending along the axial direction; "radial" refers to the radial direction of the open rotor or engine, with the radius of the fan shaft extending radially; and "circumferential" refers to the direction about the axial direction. For ease of description, the shapes of the leading edge 110 and trailing edge 120 will be described below based on their projections onto the meridional plane, with the axial and radial directions jointly defining the meridional plane.

[0043] Figure 3 This is a schematic diagram of the meridional projection of the leading and trailing edges according to some embodiments.

[0044] like Figure 3 As shown, the meridional projection 31 of the leading edge 110 is represented by the coordinate point (x1, r1), where x1 is the axial coordinate with the axial airflow direction as the positive direction, and r1 is the radial coordinate with the fan axis as the origin and the direction of increasing radius as the positive direction. The coordinate point of the blade root on the meridional projection 31 of the leading edge is represented as (x1, r1). 1，hub r 1，hub The coordinates of the leaf tip on the meridional projection 31 of the leading edge are represented as (x 1，tip r 1，tip The leading edge 110 is swept back as a whole, i.e., x 1，tip >x 1，hub .

[0045] like Figure 3 As shown, the meridional projection 32 of the trailing edge 120 is represented by the coordinate point (x2, r2), where x2 is the axial coordinate with the axial airflow direction as the positive direction, and r2 is the radial coordinate with the fan axis as the origin and the direction of increasing radius as the positive direction. The coordinate point of the blade root on the meridional projection 32 of the trailing edge 120 is represented as (x2, r2). 2，hub r 2，hub The coordinates of the blade tip on the meridional projection 32 of the trailing edge 120 are represented as (x 2，tip r 2，tip The trailing edge sweeps back 120 degrees, i.e., x 2，tip >x 2，hub .

[0046] In some embodiments, the meridional projection 31(x1, r1) of the leading edge 110 satisfies x1 = f1(r1), where f1(r1) is a cubic polynomial. Furthermore, within the radial region covered by the rotor blade 100, f1(r1) has one and only one minimum value, the coordinates of which are (x1, r1). 1，min r 1，min Minimum value coordinates (x) 1，min r 1，min The midpoint of the radial direction of the meridional projection 31 of the leading edge 110. In some embodiments, by making r 1，min r 1，hub With r 1，tip Satisfying 0.4 < (r) 1，min -r 1，hub ) / (r 1，tip -r 1，hub If ) < 0.6, then the coordinates of the minimum value (x) are determined. 1，min r 1，min The specific location of the midpoint of the meridional projection 31 of the leading edge 110. In some embodiments, by making r 1，min r 1，hub With r 1，tip Satisfying 0.45 < (r) 1，min -r 1，hub ) / (r 1，tip -r 1，hub If ) < 0.55, then the coordinates of the minimum value (x) are determined. 1，min r 1，min The specific location of the center of the meridional projection 31 at the leading edge 110.

[0047] In some embodiments, the meridional projection 32(x2, r2) of the trailing edge 120 satisfies x2 = f2(r2), where f2(r2) is a cubic polynomial. Furthermore, within the radial region covered by the rotor blade 100, f2(r2) has one and only one minimum value, the coordinates of which are (x2, r2). 2，min r 2，min Minimum value coordinates (x) 2，min r 2，min The minimum coordinate point (x) is located in the lower-middle part of the radial direction of the meridional projection 32 of the trailing edge 120. 2，min r 2，min The leaf tip 130 is positioned closer to the leaf root 140 than the leaf base 140. In some embodiments, by making r 2，min r 2，hub With r 2，tip Satisfying 0.2 < (r) 1，min -r 1，hub ) / (r 1，tip -r 1，hub If ) < 0.4, then the coordinates of the minimum value (x) are determined. 2，min r 2，minThe specific location of the lower part in the meridional projection 32 of the trailing edge 120. In some embodiments, by making r 2，min r 2，hub With r 2，tip Satisfying 0.25 < (r) 1，min -r 1，hub ) / (r 1，tip -r 1，hub If ) < 0.35, then the coordinates of the minimum value (x) are determined. 2，min r 2，min The specific location of the lower part of the meridional projection 32 of the trailing edge 120.

[0048] The three-dimensional rotor blade 100 can be considered as being formed by the stacking of several two-dimensional airfoils along the blade height direction (or radial direction). Each two-dimensional airfoil can be considered as being formed by the superposition of its mid-curve along the blade thickness direction. The mid-curve configuration is determined by the leading-edge metal angle, trailing-edge metal angle, and bend distribution. Furthermore, the mid-curve configuration varies with the blade height in two-dimensional airfoils of different blade heights. The general shape of the rotor blade 100 can be determined through the following description of the mid-curve configuration. The mid-curve of the rotor blade 100 is the line connecting the centers of the inscribed circles in the airfoil cross-section.

[0049] Figure 4 It is a distribution curve of leading edge airflow angle, leading edge metal angle and angle of attack shown in some embodiments.

[0050] In some embodiments, the angle of attack distribution of the rotor blades 100 has the following characteristics: Figure 4 The angle of attack distribution curve 41 shown indicates that the angle of attack ranges from 0° to 2° at the blade root. Considering aerodynamic stability during takeoff and other operating conditions, the angle of attack gradually decreases to a negative angle of attack as the blade height increases. The angle of attack ranges from -4° to -2° at 50% ± 5% of the blade height (where blade height refers to the radial dimension of rotor blade 100), and from -12° to -6° at the blade tip. The angle of attack is defined as the difference between the metal angle and the airflow angle. When the airflow blows towards the pressure surface of rotor blade 100, the angle of attack is positive; when the airflow blows towards the suction surface of rotor blade 100, the angle of attack is negative.

[0051] For a selected design condition (e.g., a high subsonic inflow condition), based on the inflow velocity and blade rotation speed, the relative airflow angles at each blade height of the rotor blades (100°) can be obtained in the blade motion reference frame, thus obtaining the leading-edge airflow angle distribution curve 42. Since the angle of attack is the difference between the metal angle and the airflow angle, the leading-edge metal angle can be determined based on the leading-edge airflow angle and the angle of attack, thereby obtaining the leading-edge metal angle distribution curve 43.

[0052] Figure 5 It is a distribution curve of leading edge metal angle, trailing edge metal angle and airfoil bend angle according to some embodiments.

[0053] In some embodiments, the blade bend angle is iteratively designed based on the thrust requirements of the design conditions to find a suitable blade bend angle. Generally, the greater the thrust requirement, the larger the blade bend angle, but correspondingly, the blade stability and aerodynamic efficiency will decrease. The blade bend angle distribution of the rotor blade 100 has the following characteristics: Figure 5 The blade curvature distribution curve 51 shows that the maximum blade curvature angle is located at 140° from the leaf root. From 140° to 60% ± 10% of the leaf height, the blade curvature angle shows little variation. Above 60% ± 10% of the leaf height, the blade curvature angle decreases, and the angle at 60% ± 10% of the leaf height is smaller than the maximum. The minimum blade curvature angle is located at the leaf tip, ranging from 1° to 8°. The blade curvature angle indicates the degree of curvature of the blade; a larger angle indicates a more curved blade. The blade curvature angle is the difference between the leading edge metal angle and the trailing edge metal angle. The leading edge metal angle or trailing edge metal angle refers to the angle between the tangent line of the arc line at the leading or trailing edge and the chord line (the straight line connecting the leading and trailing edges), which is also the angle less than 90° between the tangent line of the arc line at the leading edge and the tangent line of the arc line at the trailing edge. Leaf bend angle reflects the degree of twisting of the leaf from the root to the tip and is usually used to describe the three-dimensional shape characteristics of the leaf.

[0054] Since the blade bend angle is the difference between the leading edge metal angle and the trailing edge metal angle, according to... Figure 5 The blade bend angle distribution curve 51 and the leading edge metal angle distribution curve 52 (or leading edge metal angle distribution curve 43) shown can be used to obtain the trailing edge metal angle distribution curve 53.

[0055] Figure 6 It is a curve diagram showing the distribution of the bend angle at the leaf root, leaf middle and leaf tip, based on some embodiments.

[0056] In some embodiments, the leading edge angle of the mid-curve is the leading edge metal angle, and the trailing edge angle of the mid-curve is the trailing edge metal angle. The distribution pattern of the bend angles on the blade profile can be represented as the angular variation pattern of the mid-curve from the leading edge to the trailing edge. The bend angle distribution on the blade profile has the following characteristics: Figure 6 The curve shown is a curve representing the distribution of bend angles. The bend angle is the angle between the tangent at a point on the middle arc and the tangent at the leading edge or trailing edge of the middle arc.

[0057] like Figure 6 The leaf root bend angle distribution curve 61 shows that at leaf root 140, the bend angle range at 30%~40% of the leaf chord length is 20%±5%, the bend angle range at 50%~60% of the leaf chord length is 50%±5%, and the bend angle range at 70%~80% of the leaf chord length is 80%±5%. For example... Figure 6The leaf bend angle distribution curve 62 shown indicates that the leaf midpoint refers to the area at 50% ± 10% of the leaf height. The bend angle range at 5%–15% of the leaf chord length is 20% ± 5%, at 65%–75% of the leaf chord length is 50% ± 5%, and at 85%–95% of the leaf chord length is 80% ± 5%. For example... Figure 6 The leaf tip bend angle distribution curve 63 shows that at leaf tip 130, the bend angle range at 5%~15% of the leaf chord length is 20%±5% of the leaf shape bend angle; the bend angle range at 30%~40% of the leaf chord length is 50%±5% of the leaf shape bend angle; and the bend angle range at 80%~90% of the leaf chord length is 80%±5% of the leaf shape bend angle. Here, the leaf chord length is the straight-line distance from the leading edge to the trailing edge of the leaf.

[0058] Based on the dimensionless distribution of the leading edge metallic angle, trailing edge metallic angle, and mid-curve angle at each leaf height, the geometric shape of the mid-curve of the leaf shape at each leaf height can be obtained. The mid-curve at each leaf height smoothly transitions radially from the leaf tip to the leaf root. Based on this, the leaf thickness distribution and circumferential stacking form of the leaf blade are determined, and then... Figure 3 The shape of the rotor blade 100 can be constructed by limiting the leading edge shape and trailing edge shape as shown (e.g., Figure 1 and Figure 2 (As shown).

[0059] In some embodiments, the blade thickness distribution of the rotor blade 100 at each blade height is determined by the blade material and strength. The blade thickness distribution of the rotor blade 100 has the following characteristics: Figure 7 The leaf thickness distribution curve 71 shown indicates that the leaf has the position of maximum leaf thickness in terms of leaf shape, which is located at 20%~35% of the leaf chord length.

[0060] The circumferential stacking form of rotor blade 100 is as follows Figure 8 As shown, the blade profiles at each blade height are stacked according to circumferential offset, which can be understood as the offset between the vertical centerlines of the blade profiles at each blade height. Below 50% ± 5% of the blade height, the circumferential offset of the stacked blade profiles is close to 0; above 50% ± 5% of the blade height, the absolute value of the circumferential offset of the stacked blade profiles increases with the increase of the blade height, and at the blade tip, the circumferential offset of the blade profile is 0.12~0.14. It should be noted that when stacking blade profiles to form a blade, at least 20 blade profile sections should be constructed to ensure that the surface shape of the blade is smooth and controllable.

[0061] Figure 9 This is a comparison chart of isentropic Mach number distributions based on some embodiments.

[0062] Verification experiments showed that the isentropic Mach number data of the rotor blade at a typical blade height (100 blade shape) compared to the original blade shape were as follows: Figure 9As shown. Under the same thrust level, the isentropic Mach number distribution on the 100 pressure surface of a rotor blade at a typical blade height has the following characteristics: Figure 9 The isentropic Mach number distribution curve shown in Figure 91 illustrates that the isentropic Mach number distribution on the pressure surface of the original blade profile at a typical blade height exhibits the following characteristics: Figure 9 The isentropic Mach number distribution curve shown is 93; the isentropic Mach number distribution on the suction surface of the rotor blade at a typical blade height of 100 has the following characteristics: Figure 9 The isentropic Mach number distribution curve shown in Figure 92 shows that the isentropic Mach number distribution on the suction surface of the original leaf shape at a typical leaf height has the following characteristics: Figure 9 The isentropic Mach number distribution curve shown is 94. The isentropic Mach number on rotor blade 100 at a typical blade height is significantly lower than that of the original blade shape. The shock wave generated on the blade surface is weakened, or even no shock wave is generated on the blade surface. The penetrating shock wave at a typical blade height of rotor blade 100 disappears, which can avoid energy loss and improve the propulsion efficiency of open fan by 2%.

[0063] The basic concepts have been described above. It is clear that the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification, especially for those skilled in the art. Furthermore, unless expressly stated in the claims, the order of elements and sequences, the use of numbers and letters, or other names in this specification are not intended to limit the order of the processes and methods described herein. Although various examples of currently considered useful embodiments of the invention have been discussed in the foregoing disclosure, it should be understood that such details are for illustrative purposes only, and the appended claims are not limited to the disclosed embodiments. Rather, the claims are intended to cover all modifications and equivalent combinations that conform to the substance and scope of the embodiments described herein.

Claims

1. An open rotor blade, characterized in that, The open rotor blade includes a leading edge, a trailing edge, a blade tip, and a blade root; The leading edge is swept back entirely, and the axial dimension of the leading edge at the leaf tip is larger than the axial dimension of the leading edge at the leaf root; wherein, The meridional plane projection of the leading edge is represented by (x1, r1) coordinate points, wherein x1 is an axial coordinate, r1 is a radial coordinate, (x1, r1) satisfies x1=f1(r1), f1(r1) is a cubic polynomial, f1(r1) has only one minimum value, and the corresponding coordinate point is (x 1，min , r 1，min ), (x 1，min , r 1，min ) is located in the middle of the meridional plane projection of the leading edge, the coordinate point of the root of the blade on the meridional plane projection of the leading edge is (x 1，hub , r 1，hub ), the coordinate point of the blade tip on the meridional plane projection of the leading edge is (x 1，tip , r 1，tip ), wherein r 1，min , r 1，hub and r 1，tip satisfy 0.4<(r 1，min -r 1，hub ) / (r 1，tip -r 1，hub )<0.6; the trailing edge is overall swept back, the axial dimension of the trailing edge at the blade tip is greater than the axial dimension of the trailing edge at the root of the blade; wherein, The projection of the trailing edge onto the meridional plane is represented by the coordinate point (x2, r2), where x2 is the axial coordinate and r2 is the radial coordinate. (x2, r2) satisfies x2 = f2(r2), where f2(r2) is a cubic polynomial, and f2(r2) has one and only one minimum value, corresponding to the coordinate point (x2, r2). 2，min r 2，min ), (x 2，min r 2，min The leaf root is positioned closer to the leaf tip than to the leaf tip. The coordinates of the leaf root on the meridional projection of the trailing edge are (x...). 2，hub r 2，hub The coordinates of the blade tip on the meridional projection of the trailing edge are (x... 2，tip r 2，tip ), where r 2，min r 2，hub With r 2，tip Satisfying 0.2 < (r) 1，min -r 1，hub ) / (r 1，tip -r 1，hub <0.4; The leaf root has the maximum leaf shape bend angle, the leaf shape bend angle at 60%±10% of the leaf height is smaller than the maximum leaf shape bend angle, the leaf tip has the minimum leaf shape bend angle, and the angle range of the minimum leaf shape bend angle is 1°~8°.

2. The open rotor blade according to claim 1, characterized in that, The angle of attack at the leaf root ranges from 0° to 2°, the angle of attack at 50% ± 5% of the leaf height ranges from -4° to -2°, and the angle of attack at the leaf tip ranges from -12° to -6°.

3. The open rotor blade according to claim 1, characterized in that, On the leaf root, the bend angle range at 30%~40% of the leaf chord length is 20%±5% leaf bend angle, the bend angle range at 50%~60% of the leaf chord length is 50%±5% leaf bend angle, and the bend angle range at 70%~80% of the leaf chord length is 80%±5% leaf bend angle.

4. The open rotor blade according to claim 1, characterized in that, At 50%±10% of leaf height, the bend angle range at 5%~15% of leaf chord length is 20%±5% of leaf bend angle; at 65%~75% of leaf chord length, the bend angle range is 50%±5% of leaf bend angle; and at 85%~95% of leaf chord length, the bend angle range is 80%±5% of leaf bend angle.

5. The open rotor blade according to claim 1, characterized in that, At the leaf tip, the bend angle range at 5%~15% of the leaf chord length is 20%±5% leaf bend angle, the bend angle range at 30%~40% of the leaf chord length is 50%±5% leaf bend angle, and the bend angle range at 80%~90% of the leaf chord length is 80%±5% leaf bend angle.

6. The open rotor blade according to claim 1, characterized in that, The leaf has a maximum leaf thickness position, which is located at 20%~35% of the leaf chord length.

7. An open rotor, including a hub, characterized in that, It also includes rotor blades as described in any one of claims 1 to 6.

8. An open rotary engine, characterized in that, It includes rotor blades as described in any one of claims 1 to 6, or includes an open rotor as described in claim 7.

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