Open rotor, blade, engine and design method

Abstract

According to the open type rotor blade, the bending angle of 60% + / -5% of the total bending angle of the blade profile of the blade profile section of the blade tip is arranged at the position of 0%-30% of the chord length of the blade profile, and the bending angle of 60% + / -5% of the total bending angle of the blade profile section of the blade root is arranged at the position of 70%-100% of the chord length of the blade profile. The open type rotor blade has good propelling capacity. The invention further provides an open rotor, an open rotor engine and an open rotor blade design method.

Description

Technical Field

[0001] The present invention relates to the field of blades, in particular to the field of open rotor blades. Background Art

[0002] The progress of aircraft power systems is a necessary guarantee for further improving fuel efficiency and reducing emissions. The performance of an engine is determined by thermal propulsion efficiency, which can be achieved by improving propulsion efficiency and thermal efficiency. Propulsion efficiency is mainly achieved by increasing the bypass ratio, but for engines with traditional configurations, the increase in bypass ratio means an increase in the nacelle diameter, its aerodynamic resistance and weight also continue to increase, and the engine installation loss increases. When the increase in installation loss offsets the fuel saving benefits of improved propulsion efficiency, a critical point is reached.

[0003] The technical approach to improving thermal efficiency is mainly to increase the engine's total boost ratio, turbine pre-temperature, and component efficiency. However, with the development of aero-engine technology, these three factors are already at a relatively high level, and improving engine thermal efficiency poses a huge challenge to both aerodynamic design technology and material technology.

[0004] In order to solve the efficiency and emission problems, the governments and aviation industries of European and American aviation powers have jointly launched a "green aviation" revolution, launching new concepts and exploring new technologies, improving the configuration of gas turbine engines, introducing open rotors, gear transmission technology and other new configuration technologies, and improving fuel consumption. Open rotor engines are not restricted by the nacelle installation effect, so they can achieve a large bypass ratio (30-90), greatly improve propulsion efficiency, and significantly reduce fuel consumption, which is expected to exceed 20%. Summary of the invention

[0005] An object of the present invention is to provide an open rotor blade having a higher propulsion efficiency.

[0006] In order to achieve the above purpose, an open rotor blade has a blade tip section with a bending angle of 60%±5% of the total blade profile bending angle set at 0% to 30% of the blade profile chord length, and a blade root section with a bending angle of 60%±5% of the total blade profile bending angle set at 70% to 100% of the blade profile chord length.

[0007] In one or more embodiments, the camber line distribution of each cross-sectional airfoil of the blade transitions smoothly from the tip to the root of the blade.

[0008] In one or more embodiments, the center of gravity of the blade profile section at the tip of the blade is arranged to be further offset from the origin of the stacking line than the center of gravity of the blade profile section at the root of the blade. The stacking line is a line formed by the centers of gravity of each blade profile section along the blade height direction.

[0009] Another object of the present invention is to provide an open rotor, comprising a wheel disk and the above-mentioned open rotor blades.

[0010] Another object of the present invention is to provide an open rotor engine comprising the above-mentioned open rotor.

[0011] Another object of the present invention is to provide a method for designing an open rotor blade, which is used to produce the above-mentioned open rotor blade, and the method includes the following steps: obtaining different cross-sections of the blade in the radial direction; the blade profile of each cross-section adopts a different mid-arc line distribution, so that the mid-arc line distribution of the blade profile of each cross-section smoothly transitions from the tip to the root of the blade; the thickness distribution of the blade is designed using a polynomial curve; the stacking line of the blade is designed using a spline curve; and the blade profiles of each cross-section are combined into a complete blade.

[0012] In one or more embodiments, a bend angle of 60%±5% of the total bend angle of the blade tip section is designed at 0% to 30% of the chord length of the blade.

[0013] In one or more embodiments, a bend angle of 60%±5% of the total bend angle of the blade profile at the root section of the blade is designed at 70% to 100% of the chord length of the blade profile.

[0014] In one or more embodiments, the airfoil profiles of various cross sections are combined into a complete blade using a gravity stacking method.

[0015] In one or more embodiments, the thickness distribution of the blade is designed using a quartic polynomial curve.

[0016] In one or more embodiments, the stacking line of the blade is designed using a C-type third-order spline curve. In the stacking line design, the deviation of the blade root relative to the origin is made smaller than the deviation of the blade tip relative to the origin.

[0017] The above-mentioned open rotor blade constructs cross-sectional blade profiles of different blade heights by superimposing thickness distribution of the mid-arc line, and combines the blade profiles into complete blades by gravity stacking. The bending angle of 60%±5% of the total bending angle of the blade tip section is set at 0% to 30% of the blade chord length, and the bending angle of 60%±5% of the total bending angle of the blade root section is set at 70% to 100% of the blade chord length. This can target the respective characteristics of the blade tip and the blade root, so that the blade as a whole can obtain a higher propulsion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0019] Figure 1 It is a schematic diagram of the blade bending angle;

[0020] Figure 2 It is the distribution diagram of relative bending angle and relative chord length of the arc line in the blade tip section;

[0021] Figure 3 It is a schematic diagram of the blade tip cross section;

[0022] Figure 4 It is the distribution diagram of relative bending angle and relative chord length of arc line in blade root section;

[0023] Figure 5 It is a schematic diagram of the blade root cross section;

[0024] Figure 6 It is the distribution diagram of relative bending angle and relative chord length of the median arc of different cross sections;

[0025] Figure 7 is the blade thickness distribution curve;

[0026] Figure 8 It is a schematic diagram of the blade stacking line;

[0027] Fig. 9 It is a schematic diagram of the appearance of an open rotor blade. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with specific embodiments and drawings. More details are elaborated in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in a variety of other ways different from the description herein. Those skilled in the art can make similar generalizations and deductions based on actual application situations without violating the connotation of the present invention. Therefore, the protection scope of the present invention should not be limited by the content of this specific embodiment.

[0029] It should be noted that these and other subsequent drawings are only examples and are not drawn to scale, and should not be used to limit the actual scope of protection required by the present invention.

[0030] Reference for blade section parameters on the blade Figure 1 The two-dimensional airfoil profile shown in the figure is understood, point A is the leading edge, point B is the trailing edge, and the line connecting the two points is the blade chord line, as shown in b, and its length is the blade chord length, which represents the projection of the blade on the chord line. The mid-arc line refers to the curve formed by connecting the centers of the inscribed circles in the blade profile that are tangent to the blade basin and blade back curves at the same time, as shown in d. The maximum thickness of the blade is the diameter of the largest inscribed circle in the blade profile, as shown in C max As shown in , the maximum thickness position is the projection distance from the center of the maximum inscribed circle to the leading edge point A on the blade chord line b, as shown in e, and the maximum deflection position is the projection distance from the point where the distance between the mid-arc line and the chord line is the largest to the leading edge point A on the blade chord line b, as shown in a.

[0031] The leading edge angle χ1 and the trailing edge angle χ2 of the blade profile refer to the angles between the tangent of the mid-arc line d at the leading edge and the trailing edge and the chord line. The total bending angle θ of the blade profile indicates the degree of curvature of the blade profile, which is the sum of the leading edge angle χ1 and the trailing edge angle χ2. The larger the total bending angle θ of the blade profile, the more curved the blade profile.

[0032] Figure 2 , Figure 4 and Figure 6 The relative chord length represents the ratio of the chord position of the blade to the chord length of the blade profile starting from the leading edge point A, and the relative bend angle represents the ratio of the tangent line of each point on the median camber line d to the bend angle θ of the blade profile.

[0033] The stacking line is used to determine the specific position of the blade profile of each blade height section in the three-dimensional blade, and is usually a smooth curve formed by the center of gravity of each section along the radial direction (blade height direction).

[0034] An open rotor refers to an engine without a casing to contain the fan blades. The open rotor blades disclosed in the present invention have a bending angle of 60%±5% of the total bending angle θ of the blade tip section set at 0% to 30% of the blade chord length, and a bending angle of 60%±5% of the total bending angle θ of the blade root section set at 70% to 100% of the blade chord length.

[0035] like Figure 2 and Figure 3 As shown, according to the relative distribution of the relative bending angle of the mid-arc line of the blade section at the tip of the blade and the relative chord length, the bending angle of 60%±5% of the total bending angle θ of the blade is set at 0% to 30% of the chord length of the blade. Since the working capacity of the blade tip is strong, this design can achieve rapid acceleration of the airflow in the leading edge area of ​​the blade tip, thereby maximizing the workability of the blade.

[0036] Continue to refer to Figure 4 and Figure 5 As shown in the figure, the relative distribution of the relative bending angle of the mid-arc line of the blade section at the root of the blade and the relative chord length indicates that the bending angle of 60%±5% of the total bending angle of the blade appears at 70% to 100% of the chord length of the blade. Since the working capacity of the blade root is relatively weak, this design can achieve a more uniform distribution of the added power at the blade root along the chord direction, thereby minimizing the loss at the blade root while achieving a certain degree of added power.

[0037] Figure 6 The relative bending angle and relative chord length distribution diagram of the median arc line on the four blade sections of the blade are shown, wherein the solid line represents the median arc line closest to the blade tip, the dotted line represents the median arc line near the blade tip, the short dashed line represents the median arc line near the blade root, and the long dashed line represents the median arc line closest to the blade root. It can be seen that the bending angle of 60%±5% of the total blade bending angle θ is set toward the trailing edge as the blade height decreases.

[0038] Figure 7 The distribution curve of the overall thickness of the blade is shown, where the abscissa represents the relative chord length and the ordinate represents the relative thickness. Figure 8 The distribution of blade stacking lines is shown, where the abscissa represents the circumferential offset and the ordinate represents the relative blade height.

[0039] Preferably, the center of gravity on the blade profile cross section at the blade tip is arranged to be further offset from the origin of the stacking line than the center of gravity on the blade profile cross section at the blade root, so as to obtain higher propulsion efficiency.

[0040] Fig. 9 The overall external view of the open rotor blade disclosed in the present invention is shown. The mid-arc lines of the blade profiles of each cross section of the blade can achieve optimal aerodynamic performance at each blade height through the above-mentioned customized design, so that the blade as a whole has a higher propulsion efficiency.

[0041] In combination with the above introduction to the open rotor blades, we can also understand an open rotor with the blades and an open rotor engine with the above open rotor.

[0042] The present disclosure also introduces a method for designing the above-mentioned open rotor blades, comprising the following steps: firstly obtaining different sections of the blade in the radial direction, such as sections at the blade tip, the blade root, and multiple sections of the blade body; then making the blade profile of each section adopt different mid-arc distributions, such as designing the angle of 60%±5% of the total angle of the blade profile of the blade tip section at 0% to 30% of the blade profile chord length, and designing the angle of 60%±5% of the total angle of the blade profile of the blade root section at 70% to 100% of the blade profile chord length. Make the mid-arc distribution of the blade profile of each section generally smoothly transition from the blade tip to the root.

[0043] The thickness distribution of the blade is designed using a polynomial curve, the stacking line of the blade is designed using a spline curve, and finally the blade shapes of each section are combined into a complete blade.

[0044] In some embodiments, the thickness distribution of the blade is designed using a quartic polynomial curve, and the stacking line of the blade is designed using a C-type third-order spline curve, so that the deviation of the blade root relative to the origin is smaller than the deviation of the blade tip relative to the origin. The origin represents a point with a relative blade height of 0 and a circumferential offset of 0, such as Figure 8 As shown by the point (0,0) in the middle. For example, the deviation degree of the blade root from the origin is made as small as possible within the optional range, and the deviation degree of the blade tip from the origin is made as large as possible within the optional range, so that the deviation degree of the blade root from the origin is smaller than the deviation degree of the blade tip from the origin. The centroid stacking method is used to combine the blade profiles of each section into a complete blade.

[0045] The present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or multiple times in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0046] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0047] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. An open rotor blade, characterized in that: An angle of 60%±5% of the total blade curvature of the blade section at the tip of the blade is set at 0% to 30% of the blade chord length, and an angle of 60%±5% of the total blade curvature of the blade section at the root of the blade is set at 70% to 100% of the blade chord length.

2. The open rotor blade according to claim 1, characterized in that: The mid-arc distribution of each cross-section blade profile of the blade smoothly transitions from the blade tip to the root.

3. The open rotor blade according to claim 1, characterized in that: The center of gravity on the blade profile section at the blade tip is arranged to be further offset from the origin of the stacking line than the center of gravity on the blade profile section at the blade root. The stacking line is a line formed by the centers of gravity of each blade profile section along the blade height direction.

4. An open rotor, including a wheel disc, characterized in that: It also comprises the open rotor blade according to any one of claims 1-3.

5. An open rotor engine, characterized in that: Comprising the open rotor as claimed in claim 4.

6. An open rotor blade design method, characterized in that: For producing the open rotor blade according to any one of claims 1 to 3, the method comprises the following steps: Obtain different cross sections of the blade in the radial direction; The blade profiles of each section adopt different mid-arc distributions, so that the mid-arc distributions of the blade profiles of each section have a smooth transition from the blade tip to the root; The thickness distribution of the blade is designed using a polynomial curve; The stacking line of the blades is designed by a spline curve; Combine the blade profiles of each section into a complete blade.

7. The method for designing an open rotor blade according to claim 6, characterized in that: The bending angle of 60%±5% of the total bending angle of the blade tip section is designed at 0% to 30% of the blade chord length.

8. The open rotor blade design method according to claim 6, characterized in that: The bending angle of 60%±5% of the total bending angle of the blade root section is designed to be at 70% to 100% of the blade chord length.

9. The method for designing an open rotor blade according to claim 6, wherein: The blade profiles of each section are combined into a complete blade using the gravity stacking method.

10. The method for designing an open rotor blade according to claim 6, wherein: The thickness distribution of the blade is designed by adopting a fourth-order polynomial curve.

11. The method for designing an open rotor blade according to claim 6, wherein: The stacking line of the blade is designed by a C-type third-order spline curve. In the stacking line design, the deviation degree of the blade root relative to the origin is made smaller than the deviation degree of the blade tip relative to the origin.

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