Turbine engine rotor blade with wavy trailing edge

Abstract

The invention relates to a turbine engine rotor blade (10) comprising a blade body (10), a root (4) intended to be embedded in an axial tongue-and-groove (3) fixed to a turbine disk (2), and a connection section (5) connecting the blade body (10) and the root (4), the blade profile (20) of the blade body (10) in the blade height direction being continuously variable, characterized in that the blade body comprises a continuously smooth wave-shaped trailing edge (14). The smooth wave-shaped trailing edge feature is particularly effective in the aspect of reducing resistance generated when the blade rotates. By minimizing resistance, the turbine can produce greater power, while the overall energy consumption is lower.

Description

Technical Field

[0001] The invention relates to the technical field of aviation engines, and in particular to a turbine rotor blade with a wavy trailing edge. Background Art

[0002] Existing aircraft engines use gas turbine engines to convert the internal energy of high-temperature combustion gas into kinetic energy through rotors. The rotor blades are connected to the tenon structure of the engine turbine disk through a tenon structure. Among them, in order to ensure good turbine aerodynamic performance, the blade body has a high degree of three-dimensionality, usually composed of a series of two-dimensional blades with varying shapes and bending angles stacked along the radial direction of the turbine disk. The shape of the trailing edge of the blade can generate vortices, which helps to improve the efficiency and performance of the turbine.

[0003] In recent years, inspired by the silent flight of owls, the trailing edge of blades has been designed into a sawtooth structure to reduce noise in fields such as wind power generation and aircraft engines. However, the existing sawtooth structure has simple design parameters and a small design space, which cannot meet the performance requirements of turbines. Summary of the invention

[0004] An object of the present invention is to provide a rotor blade capable of further improving the performance of a turbine.

[0005] To this end, the present invention provides a turbine engine rotor blade, comprising a blade body, a root, and a connecting section connecting the blade body and the root, wherein the root is used to be embedded in an axial groove fixed to a turbine disk, and the blade profile of the blade body along the blade height direction is continuously changed, and is characterized in that the blade body comprises a continuous and smooth wavy trailing edge.

[0006] It should be understood that the so-called "blade height direction" is the radial direction of the turbine disk. The so-called "continuously smooth" trailing edge means that the curve defining the trailing edge satisfies the mathematical definition of a "continuous smooth curve". It should be understood that its shape is different from the known "serrated" trailing edge. Sawtooth refers to a periodic non-sinusoidal wave that rises in a straight line, then drops sharply, then rises again, and then drops sharply. The trailing edge shape that conforms to the present invention is a continuous and smooth wave shape. The inventor has found through simulation experiments that this smooth and wavy trailing edge feature is particularly effective in reducing the resistance generated when the blades rotate. By minimizing resistance, the turbine can generate more power while consuming less energy overall.

[0007] According to some embodiments of the present invention, the tangential chord length TC* and the axial chord length AC* of the blade profile continuously change in equal proportion, thereby specifically achieving the feature that the trailing edge of the blade presents a continuous and smooth wave change along the blade height direction.

[0008] More specifically, according to some embodiments of the present invention, the tangential chord length TC* and the axial chord length AC* of the blade profile are defined by the following equations (a) and (b), respectively:

[0009] TC * =TC·sf (a)

[0010] AC * =AC·sf (b)

[0011] Where sf is a scaling coefficient sequence that changes continuously along the blade height, TC is the initial tangential chord length parameter, AC is the initial axial chord length parameter, and sf is obtained by superimposing the sine function and the cosine function. As a result, the tangential chord length TC* and the axial chord length AC* of the blade profile change continuously in equal proportion, achieving the characteristic of continuous smooth wave changes along the blade height of the trailing edge of the blade. Moreover, sf is not a single sine function, but is obtained by superimposing the sine function and the cosine function, so that a larger design space can be obtained to select the best parameter combination that meets the turbine design requirements.

[0012] More specifically, the sf is defined by the following formula (c):

[0013]

[0014] Among them, δ1 is the step length of the sinusoidal function from the blade root to the blade height,

[0015] δ2 is the step length of the direction cosine function from the leaf root to the leaf height,

[0016] α is the frequency scaling coefficient sequence of the sine function from the blade root to the blade height, α=[α1,α2,…,α N ],

[0017] β is the frequency scaling coefficient sequence of the direction cosine function from the blade root to the blade height, β=[β1,β2,…,β N ],

[0018] τ1 is the amplitude offset parameter of the sine function along the blade height direction,

[0019] τ2 is the amplitude offset parameter of the cosine function along the leaf height direction,

[0020] τ3 is the amplitude offset parameter for generating the scaling sequence along the leaf height direction,

[0021] A is the scaling sequence of the sine function amplitude along the leaf height direction, A=[A1,A2,…,A N ],

[0022] B is the scaling sequence of the sine function amplitude along the leaf height direction, B = [B1, B2, ..., B N ].

[0023] The present invention also proposes a design method for designing a turbine engine rotor blade as described above, characterized in that, in view of the specific design requirements of turbine performance, a CFD method is used to calculate the trailing edge design parameter combination based on formula (c). According to this method, based on turbine aerodynamic calculations, the best sine and cosine function superposition combination suitable for turbine performance design requirements can be quickly found in the design space. In fact, with the improvement of aerodynamic calculation efficiency, the present invention can generate a series of blade continuous smooth wavy trailing edge design schemes based on the sine and cosine function superposition characteristics based on a fixed algorithm, and then in view of the specific design requirements of turbine performance, a CFD method is used to quickly find the best trailing edge design parameter combination in the design space. Compared with known design methods such as "periodic sawtooth trailing edge", the design method according to the present invention has a larger design space and a degree of freedom of trailing edge feature changes, which can improve the fit to turbine performance requirements, and thereby further improve turbine performance.

[0024] Finally, the invention also relates to a turbine engine comprising a turbine disk and a plurality of turbine engine rotor blades as described above.

[0025] It should be understood that the above general description and the following detailed description are exemplary and explanatory only and cannot limit the present invention. Other features, objects and advantages of the present invention will become apparent from the specification, drawings and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present invention. For illustrative purposes, these drawings may not be drawn completely to scale.

[0027] Figure 1 It is a partial stereoscopic schematic diagram of two adjacent rotor blades assembled onto a turbine disk in the prior art.

[0028] Figure 2 1 is a schematic perspective view of a blade body of a rotor blade according to the present invention.

[0029] Figure 3 yes Figure 2 Schematic diagram of the blade profile along the AA section of the blade shown. DETAILED DESCRIPTION

[0030] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments according to the present invention. Instead, they are merely examples of devices consistent with some aspects of the present invention as detailed in the appended claims.

[0031] Figure 1 FIG. 2 shows the assembly of a rotor blade 1 and a turbine disk 2 in an aircraft engine in the prior art. Figure 1 As shown, a plurality of tenons 3 are equidistantly arranged on the circumference of the turbine disk 1. These tenons 3 generally extend along the axial direction of the rotation axis of the turbine disk 2, but may also be inclined at a certain angle to the axial direction. Each rotor blade 1 includes a blade body 10 and a root 4, and a connecting section 5 connecting them. The shape of the root 4 is complementary to the tenon 3, so the root 4 can also be called a tenon. The assembly of each rotor blade 10 is achieved by embedding and fixing the root 4 into the tenon 3. The blade body 10 includes a leading edge 12 and a trailing edge 14. For a turbine, the so-called "front" refers to the side where the airflow reaches the blade, and the "rear" refers to the opposite side, that is, the side where the airflow leaves the blade. As shown Figure 1 As shown, the trailing edge 14 in the prior art is a smooth curve without any design features. Of course, there are also trailing edges with straight line serrated features in the prior art.

[0032] Figure 2 The blade body 10 of the rotor blade 1 according to the present invention is schematically shown. In fact, those skilled in the art know that in order to better meet the aerodynamic requirements, the shape and bending angle of the cross section of the blade body 10 in the blade height direction H are constantly changing with the height, and each cross section is called a blade profile 20. It can be considered that the blade body 10 is formed by stacking a plurality of continuously changing blade profiles 20 along the blade height direction H. Figure 2 This is only a schematic diagram, and the shape and angle changes of the blade profile 20 in the blade height direction are not shown. Figure 1 The rotor blades of the prior art shown differ in that Figure 2 The trailing edge 14 of the blade 10 according to the present invention shown in FIG. 1 is in a continuous and smooth wavy shape. This smooth and wavy trailing edge feature is particularly effective in reducing the drag generated when the blade rotates. By minimizing the drag, the turbine can produce more power while consuming less energy overall.

[0033] Figure 3A schematic diagram of the blade profile 20 along the AA section is shown, and in particular, the tangential chord length TC* and the axial chord length AC* of the blade profile are shown. It should be understood that since the angle of the blade profile 20 changes with the blade height, TC* and AC* are both two-dimensional vectors on the cross section. According to a preferred embodiment of the present invention, the tangential chord length TC* and the axial chord length AC* change continuously in equal proportion, and more preferably, they are defined by the following formulas (a) and (b), respectively:

[0034] TC * =TC·sf (a)

[0035] AC * =AC·sf (b)

[0036] Where sf is a scaling coefficient sequence that changes continuously along the blade height direction, TC is an initial tangential chord length parameter, AC is an initial axial chord length parameter, and sf is obtained by superposition of a sine function and a cosine function. According to a specific embodiment, sf is defined by the following formula (c):

[0037]

[0038] Among them, δ1 is the step length of the sinusoidal function from the blade root to the blade height,

[0039] δ2 is the step length of the direction cosine function from the leaf root to the leaf height,

[0040] α is the frequency scaling coefficient sequence of the sine function from the blade root to the blade height, α=[α1,α2,…,α N ],

[0041] β is the frequency scaling coefficient sequence of the direction cosine function from the blade root to the blade height, β=[β1,β2,…,β N ],

[0042] τ1 is the amplitude offset parameter of the sine function along the blade height direction,

[0043] τ2 is the amplitude offset parameter of the cosine function along the leaf height direction,

[0044] τ3 is the amplitude offset parameter for generating the scaling sequence along the leaf height direction,

[0045] A is the scaling sequence of the sine function amplitude along the leaf height direction, A=[A1,A2,…,A N ],

[0046] B is the scaling sequence of the sine function amplitude along the leaf height direction, B = [B1, B2, ..., B N ].

[0047] As a result, the tangential chord length TC* and the axial chord length AC* of the blade profile change continuously in equal proportion, achieving the characteristic of continuous smooth wave changes along the blade height of the trailing edge of the blade. Moreover, sf is not a single sine function, but is obtained by superimposing the sine function and the cosine function, so that a larger design space can be obtained to select the best parameter combination that meets the turbine design requirements.

[0048] According to the design method of the present invention, the CFD method is used to calculate the trailing edge design parameter combination based on formula (c) for the specific design requirements of the turbine performance. According to this method, a series of blade continuous smooth wave trailing edge design schemes based on the superposition characteristics of sine and cosine functions can be generated based on a fixed algorithm, and then the CFD method is used to quickly find the best trailing edge design parameter combination in the design space for the specific design requirements of the turbine performance. The design method according to the present invention has a larger design space and the degree of freedom of the trailing edge feature change, which can improve the fit to the turbine performance requirements, and thereby further improve the turbine performance.

[0049] Unless otherwise defined, the technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art of the technical field of the present invention. The terms used in this application are only for the purpose of describing specific embodiments, but are not intended to limit the present invention. The singular forms of "a", "an" and "the" used in this application are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" that may be used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0050] Terms such as "upper", "lower", "left", "right", "front", "back", "thickness", "radial", "axial" and the like that may be used herein to indicate relative positions in space are for the purpose of convenience of description to describe the relationship of one feature relative to another feature as shown in the accompanying drawings, and are not limited to one position or one spatial orientation. It is understood that, depending on the placement of the product, the terms of relative positions in space may be intended to include different orientations in addition to the orientation shown in the drawings, and should not be understood as limiting. Words such as "include" or "comprise" and the like used herein mean that the elements or objects appearing before "include" or "comprises" include the elements or objects listed after "include" or "comprises" and their equivalents, and do not exclude other elements or objects.

[0051] It should be understood that the terms “first”, “second” and similar terms used in the present application specification do not indicate any order, quantity or importance, but are only used to distinguish different components.

[0052] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A turbine engine rotor blade (1), comprising a blade body (10), a root (4), and a connecting section (5) connecting the blade body (10) and the root (4), wherein the root (4) is used to be embedded in an axial groove (3) fixed to a turbine disk (2), and the blade profile (20) of the blade body (10) along the blade height direction is continuously changed, characterized in that: The blade airfoil comprises a continuous and smooth wavy trailing edge (14).

2. The turbine engine rotor blade (1) according to claim 1, characterized in that The tangential chord length TC* and the axial chord length AC* of the blade profile (20) vary continuously and in equal proportion.

3. The turbine engine rotor blade (1) according to claim 1, characterized in that The tangential chord length TC* and the axial chord length AC* of the blade profile (20) are defined by the following equations (a) and (b), respectively: TC * =TC·sf (a) AC * =AC·sf (b) Where sf is a scaling coefficient sequence that changes continuously along the blade height direction, TC is the initial tangential chord length parameter, AC is the initial axial chord length parameter, and sf is obtained by superimposing the sine function and the cosine function.

4. The turbine engine rotor blade (1) according to claim 3, characterized in that The sf is defined by the following formula (c): Among them, δ1 is the step length of the sinusoidal function from the blade root to the blade height, δ2 is the step length of the direction cosine function from the leaf root to the leaf height, α is the frequency scaling coefficient sequence of the sine function from the blade root to the blade height, α=[α1,α2,…,α N ], β is the frequency scaling coefficient sequence of the direction cosine function from the blade root to the blade height, β=[β1,β2,…,β N ], τ1 is the amplitude offset parameter of the sine function along the blade height direction, τ2 is the amplitude offset parameter of the cosine function along the leaf height direction, τ3 is the amplitude offset parameter for generating the scaling sequence along the leaf height direction, A is the scaling sequence of the sine function amplitude along the leaf height direction, A=[A1,A2,…,A N ], B is the scaling sequence of the sine function amplitude along the leaf height direction, B = [B1, B2, ..., B N ].

5. A method for designing a turbine engine rotor blade (1) as claimed in any one of claims 4, characterized in that: According to the specific design requirements of turbine performance, the CFD method is used to calculate the trailing edge design parameter combination based on formula (c).

6. A turbine engine comprising a turbine disk (2) and a plurality of turbine engine rotor blades (1) according to any one of claims 1 to 4.

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