Turbine blade non-uniform wing cutter design method

Abstract

The invention provides a turbine blade non-uniform wing cutter design method, and relates to the technical field of turbine machinery broadband vibration noise control, and the method comprises the following steps: arranging 2-4 layers of blade wing cutters in the direction from the blade root to the blade tip of a turbine blade, and limiting the position, thickness and layer number of the blade wing cutters; and constructing a nonlinear change amplitude value of the blade winged knife by adopting a Bezier curve. The blade winged knives are continuously distributed on the front edge and the suction surface of the turbine blade, disturbance of the blade winged knives to flow on the surface of the turbine blade is reduced, the turbulence intensity of the surface of the blade is restrained, and therefore effective restraining of random pressure pulsation induced by turbulence on the surface of the turbine blade is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of wide-band vibration and noise control of turbomachinery, and in particular to a method for designing non-uniform blades of turbine blades. Background Art

[0002] As the core component of the rotary propulsion system, turbomachinery is widely used in surface ships, nuclear-powered submarines, aircraft and other equipment. In the cruising state, the turbine blades work in a three-dimensional, non-uniform, complex unsteady turbulent flow field, and are subjected to the random pulsating pressure induced by turbulence, which in turn produces random structural vibrations in a wide band and radiates broadband noise. There is currently a lack of effective control measures for the broadband vibration noise radiated by turbomachinery, which not only affects the ecological environment, but also directly affects the acoustic stealth performance of military equipment such as submarines. Therefore, it is of great significance to carry out turbulence control in the blade channel to suppress the broadband vibration noise of turbomachinery in response to the random pulsating pressure on the blade surface induced by turbulence.

[0003] Various unsteady secondary vortices in the blade channel induce random turbulent flow. Among them, the secondary flow in the end area caused by the complex pressure gradient inside the turbine is the main reason for the increase in turbulence intensity, which in turn induces broadband random pressure pulsations on the blade surface.

[0004] The existing technology has a relatively mature understanding of the formation and development mechanism of secondary flow in the turbine end area, and a series of control methods have begun to emerge. Among them, the blade wing design, as a passive control method, has the advantages of simplicity, low cost, and reliability. It is currently used to optimize the aerodynamic performance of turbomachinery. The blade wing mainly includes two types: end wall blade wing and blade blade wing. The end wall blade wing inhibits the secondary flow in the end area by blocking the lateral flow near the end wall and combing the flow field. The blade blade wing inhibits the formation and development of the secondary flow in the end area by setting the blade wing on the blade surface, thereby reducing the secondary flow loss.

[0005] However, the existing blade blade design method does not take into account the suppression of turbulent flow on the blade surface, and still has some shortcomings. For example, the arrangement of the blade blade on the end wall will cause the flow to stagnate at the leading edge of the blade blade, resulting in the emergence of a new end-zone vortex system structure; for example, the blade blades on the blades are generally arranged in isolation on the leading edge, pressure surface or suction surface of the blade, which cannot fully and effectively suppress the turbulent flow induced by the development of the secondary flow in the end zone on the blade surface, and the inappropriate and abrupt blade blade design is likely to increase the disturbance to the fluid, thereby inducing an increase in the turbulence intensity on the blade surface (especially the suction surface).

[0006] In view of this, how to provide a blade wing design method that can partially or completely solve the above-mentioned technical problems is an issue that technical personnel in this field urgently need to solve. Summary of the invention

[0007] The purpose of the present invention is to provide a method for designing a non-uniform wing blade of a turbine blade to solve the problems existing in the prior art.

[0008] To achieve the above object, the present invention provides a method for designing a non-uniform blade blade of a turbine blade, wherein the blade blade blade is arranged on the turbine blade, comprising the following steps:

[0009] 2-4 layers of blade blades are arranged from the root of the turbine blade to the tip of the blade. The height of the center of the blade blade from the root is N·h f ; where N is the number of blade blade layers from the root to the tip of the turbine blade, h f is the blade wing position reference, h f The selection range is [h fmin ,h fmax ],h fmin =min{5%h 叶 , 20mm}, h fmax =min{10%h 叶 , 40mm}, h 叶 is the height of the turbine blades.

[0010] Furthermore, the thickness of the blade blade is 2 / 3h f .

[0011] Furthermore, the nonlinear variation amplitude of the blade blade is constructed using the Bézier curve, and the expression is as follows: f (x) = A m α(x), where A f (x) is the design amplitude of the blade blade at different axial positions on the turbine blade surface; the turbine blade surface has a pressure surface and a suction surface, and a blade channel is formed between adjacent turbine blades. x is the normalized axial position in the blade channel, and the value range is [-1,1]. When x=-1 and x=1, it is located at the trailing edge of the turbine blade; when x=0, it is located at the leading edge of the turbine blade; when -1<x<0, it is located on the pressure surface; when 0<x<1, it is located on the suction surface; A m The blade blade amplitude design benchmark is in the range of 3% to 7%C x , C x is the axial chord length of the turbine blade; α(x) is the blade wing design amplitude control coefficient that varies non-uniformly with the normalized axial position.

[0012] Furthermore, the Bézier curve is used to construct α(x), which is expressed as follows: Where z is the path parameter of the Bézier curve, ranging from 0 to 1, P i are the curve control points.

[0013] Furthermore, the blade blades of the first layer are located near the blade roots of the turbine blades, and the blade blades of the second layer and above are arranged above the blade blades of the first layer;

[0014] The normalized axial position range of the first layer of blade blades distributed on the surface of the turbine blade is x = [-0.2, 1]. The non-uniform change curve of the blade blade amplitude is determined according to the Bézier curve in the range of x = [-0.2, 1]. The curve control points are as follows: P1 (x = -0.2, y = 0), P2 (x = -0.1, y = 3), P3 (x = 0, y = 1), P4 (x = 0.1, y = 0.5), P5 (x = 0.2, y = 1.1), P6 (x = 0.5, y = 1.1), P7 (x = 0.8, y = 1.1), P8 (x = 0.9, y = 1.1), P9 (x = 1, y = 0);

[0015] The normalized axial position range of the blade blades of the second layer and above on the turbine blade surface is x = [-0.2, 0.2]. The non-uniform change curve of the blade blade amplitude is determined according to the Bézier curve within the range of x = [-0.2, 0.2]. The curve control points are as follows: P 10 (x=-0.2,y=0), P 11 (x=-0.1,y=2.1), P 12 (x=0,y=2.1),P 13 (x=0.1, y=0), P 14 (x=0.2, y=0);

[0016] Among them, y is the blade wing design amplitude control coefficient corresponding to the curve control point that varies non-uniformly with the normalized axial position.

[0017] The present invention discloses the following technical effects:

[0018] 1. The present invention realizes the parametric design of non-uniform blade blades on the surface of turbine blades, adopts the Bézier curve to control the non-uniform change process of blade blade amplitudes at different blade heights, and determines the position of blade blades at each layer according to the turbine blade configuration; the blade blades are continuously distributed on the leading edge and suction surface of the turbine blade, which suppresses the turbulence intensity on the blade surface, thereby avoiding the increase of turbulence intensity.

[0019] 2. The present invention optimizes the formation of secondary flow in the end area of ​​the blade blade and its development on the surface of the turbine blade, thereby significantly reducing the random excitation of turbulence in a large area of ​​the turbine blade surface. The multi-layer blade blades at the leading edge of the turbine blade weaken the radial pressure gradient at the leading edge, suppress the intensity of the horseshoe vortex formation, and thus suppress the intensity of the end area secondary flow in the blade channel; the first layer of blade blades extends to the suction surface, effectively blocking the development process of various vortex structures such as horseshoe vortices, channel vortices, and wall vortices on the suction surface on the turbine blade surface, significantly reducing the impact of the end area secondary flow on the blade surface, and effectively suppressing the turbulence intensity on the turbine blade surface, thereby achieving effective suppression of turbulence-induced random pressure pulsations on the turbine blade surface.

[0020] 3. This method has the advantages of few design parameters, strong universality, and small flow field disturbance. After reasonable design, it can effectively improve the formation and development of the secondary flow in the end area in the blade channel and on the blade surface, reduce the turbulence intensity, and thus significantly reduce the random turbulence excitation on the blade surface, and has little effect on the aerodynamic performance of the turbine blade itself. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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.

[0022] Figure 1 A schematic diagram of the spanwise shape of the blade blade design;

[0023] Figure 2 Design the amplitude control coefficient control points and curve diagram for the blade wing;

[0024] Figure 3 It is the configuration diagram of two layers of non-uniform blades;

[0025] Figure 4 It is a top view of the blade wing configuration;

[0026] Figure 5 This is a comparison diagram of the spanwise distribution of turbulent kinetic energy at the turbine blade passage outlet;

[0027] Figure 6 The power spectrum distribution comparison diagram of the random pulsating pressure induced by turbulence on the suction surface of the turbine blade;

[0028] Figure 7 This is a comparison of the PSD spectra of broadband random pressure pulsation at a point on the suction surface of the turbine blade;

[0029] Among them, 1. turbine blades; 101. pressure surface; 102. suction surface; 2. first layer blade wing blades; 3. second layer and above blade wing blades; 4. end wall. DETAILED DESCRIPTION

[0030] 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.

[0031] 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.

[0032] Example

[0033] An embodiment of the present invention provides a method for designing a non-uniform blade blade of a turbine blade, wherein the blade blade blade is arranged on a turbine blade 1, and the blade roots of a plurality of turbine blades 1 are arranged on an end wall 4, comprising the following steps:

[0034] 2-4 layers of blade blades are arranged from the root of turbine blade 1 to the tip of the blade, and the height of the center of the blade blade from the root is N·h f ; where N is the number of blade blade layers from the root to the tip of turbine blade 1, h f is the blade wing position reference, h f The selection range is [h fmin ,h fmax ],h fmin =min{5%h 叶 , 20mm}, h fmax =min{10%h 叶 , 40mm}, h 叶 is the height of the turbine blade 1.

[0035] like Figure 1 As shown, in this embodiment, the thickness of the blade blade is 2 / 3h f The blade blade is generally a symmetrical wave crest structure, so the upper and lower thicknesses of the blade blade are both 1 / 3h f .

[0036] In this embodiment, the nonlinear variation amplitude of the blade blade is constructed using the Bézier curve, and the expression is as follows: f (x) = A m α(x), where A f(x) is the design amplitude of the blade blade at different axial positions on the surface of the turbine blade 1; the surface of the turbine blade 1 has a pressure surface 101 and a suction surface 102, and a blade channel is formed between adjacent turbine blades 1. x is the normalized axial position in the blade channel, and the value range is [-1,1]. When x=-1 and x=1, it is located at the trailing edge of the turbine blade 1, when x=0, it is located at the leading edge of the turbine blade 1, when -1<x<0, it is located on the pressure surface 101, and when 0<x<1, it is located on the suction surface 102; A m The blade blade amplitude design benchmark is in the range of 3% to 7%C x , C x is the axial chord length of turbine blade 1; α(x) is the blade wing design amplitude control coefficient that varies non-uniformly with the normalized axial position.

[0037] In this embodiment, the Bézier curve is used to construct α(x), and its expression is as follows: Where z is the path parameter of the Bézier curve, ranging from 0 to 1, P i are the curve control points.

[0038] In this embodiment, the first layer of blade blades 2 are located near the blade root of the turbine blade 1, and the second layer and above of blade blades 3 are arranged above the first layer of blade blades 2;

[0039] like Figure 2 As shown, the normalized axial position range of the first layer of blade blades 2 distributed on the surface of the turbine blade 1 is x=[-0.2,1], and the non-uniform change curve of the blade blade amplitude is determined according to the Bézier curve in the range of x=[-0.2,1], and the curve control points are as follows: P1 (x=-0.2, y=0), P2 (x=-0.1, y=3), P3 (x=0, y=1), P4 (x=0.1, y=0.5), P5 (x=0.2, y=1.1), P6 (x=0.5, y=1.1), P7 (x=0.8, y=1.1), P8 (x=0.9, y=1.1), P9 (x=1, y=0);

[0040] The normalized axial position range of the blade blades 3 of the second layer and above distributed on the surface of the turbine blade 1 is x=[-0.2, 0.2]. The non-uniform variation curve of the blade blade amplitude is determined according to the Bézier curve within the range of x=[-0.2, 0.2]. The curve control points are as follows: P 10 (x=-0.2,y=0), P 11 (x=-0.1,y=2.1), P 12 (x=0,y=2.1),P 13 (x=0.1, y=0), P 14(x=0.2, y=0);

[0041] Among them, y is the blade wing design amplitude control coefficient corresponding to the curve control point that varies non-uniformly with the normalized axial position.

[0042] Experimental example

[0043] The above embodiment is applied to design the blade blade of turbine blade 1. The turbine blade 1 selects the annular blade of high-pressure turbine rotor blade as the design object, and the control effect of the blade blade blade configuration designed in this example on the turbulence intensity on the surface of turbine blade 1 and its induced broadband random pressure pulsation is studied through numerical simulation.

[0044] The height of turbine blade 1 is h 叶 =55mm, the axial chord length of turbine blade 1 is C x =54mm. Therefore, the blade blade position reference h is selected f =7.5%h 叶 The blade blade thickness is Select blade blade amplitude design benchmark A m =4%C x .

[0045] The blade blades are set in two layers. The amplitude control coefficient determined by the Bézier curve determines the change of the blade blade amplitude of each layer with the normalized axial position, and the non-uniform blade blade is obtained as follows: Figure 3 As shown, and a top view of a single turbine blade 1 is shown Figure 4 shown.

[0046] Numerical simulation calculations were carried out for the initial blade configuration and the blade blade configuration designed in this embodiment, respectively, to compare the turbulent kinetic energy distribution at the outlet section of the turbine blade 1 channel, to verify the effectiveness of the blade blade design disclosed in this embodiment on the control of turbulent flow in the turbine blade 1 channel, and the circumferential distribution comparison of the turbulent kinetic energy at the outlet section of the turbine blade 1 channel was calculated as follows: Figure 5 shown.

[0047] Depend on Figure 5 It can be seen that when the blade blade configuration designed in this embodiment is adopted, at 20% to 60% h 叶 Within this range, the turbulent kinetic energy in the turbine blade 1 channel is effectively reduced, especially at 30% h 叶 Nearby, the turbulent kinetic energy can be reduced by up to about 50%; however, the blade blade, as a raised structure on the surface of the turbine blade 1, increases the slight disturbance to the fluid, resulting in a decrease in the turbulent kinetic energy at 20% h. 叶 The turbulent kinetic energy increases slightly in the following range. In summary, the blade wing designed in this embodiment effectively suppresses the turbulence intensity in a larger area of ​​the passage of the turbine blade 1 .

[0048] The time domain signal of the fluctuating pressure on the surface of turbine blade 1 is extracted, and the power spectrum density (Φ pp , PSD) spectrum. Based on the extracted power spectrum density of the pulsating pressure on the surface of turbine blade 1, the power spectrum distribution in a wide frequency range is obtained by integral calculation. The expression is as follows: PS = ∫PSD df, where PS is the power spectrum of turbulent excitation in the integral frequency range. The power spectrum distribution of random pulsating pressure on the surface of turbine blade 1 in the frequency range of 0 to 4 kHz is calculated. Figure 6 As shown. The PSD logarithmic spectrum of the random pressure pulsation at a point on the suction surface 102 of the turbine blade 1 is extracted. Figure 7 The results show that the random pulsating pressure induced by turbulence on the surface of the turbine blade 1 is effectively suppressed in a large area under the action of the blade blade configuration designed in this embodiment, and the turbulent random excitation is significantly reduced in a wide frequency range.

[0049] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0050] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for designing a non-uniform blade blade of a turbine blade, wherein the blade blade blade is arranged on a turbine blade (1), characterized in that: The following steps are involved: 2-4 layers of blade blades are arranged from the blade root to the blade tip of the turbine blade (1), and the height of the center position of the blade blade from the blade root is N·h f ; where N is the number of blade blade layers from the blade root to the blade tip of the turbine blade (1), h f is the blade wing position reference, h f The selection range is [h fmin ,h fmax ],h fmin =min{5%h 叶 ,20mm},h fmax =min{10%h 叶 ,40mm},h 叶 is the height of the turbine blade (1).

2. A method for designing a non-uniform blade of a turbine blade according to claim 1, characterized in that: The thickness of the blade blade is 2 / 3h f .

3. A method for designing a non-uniform blade of a turbine blade according to claim 2, characterized in that: The non - linear varying amplitude of the blade wing knife is constructed by using Bézier curve, and the expression is as follows: A f (x)=A m ·α(x), where A f (x) is the designed amplitude at different axial positions on the surface of the blade wing knife of the turbine blade (1); the surface of the turbine blade (1) has a pressure surface (101) and a suction surface (102), and a blade passage is formed between adjacent turbine blades (1). x is the normalized axial position in the blade passage, and its value range is [- 1,1]. When x = - 1 and x = 1, it is located at the trailing edge of the turbine blade (1). When x = 0, it is located at the leading edge of the turbine blade (1). When - 1 < x < 0, it is located on the pressure surface (101). When 0 < x < 1, it is located on the suction surface (102); A m is the amplitude design reference of the blade wing knife, and its value range is 3% - 7%C x , C x is the axial chord length of the turbine blade (1); α(x) is the design amplitude control coefficient of the blade wing knife that varies non - uniformly with the normalized axial position.

4. A method for designing a non-uniform blade of a turbine blade according to claim 3, characterized in that: The Bézier curve is used to construct α(x), and its expression is as follows: Where z is the path parameter of the Bézier curve, ranging from 0 to 1, P i are the curve control points.

5. A method for designing a non-uniform blade of a turbine blade according to claim 4, characterized in that: The first layer of blade blades (2) are located near the blade roots of the turbine blades (1), and the second layer and above of blade blade blades (3) are arranged above the first layer of blade blades (2); The normalized axial position range of the first layer of blade blades (2) distributed on the surface of the turbine blade (1) is x=[-0.2, 1], and the non-uniform change curve of the blade blade amplitude is determined according to the Bézier curve within the range of x=[-0.2, 1]. The curve control points are as follows: P1 (x=-0.2, y=0), P2 (x=-0.1, y=3), P3 (x=0, y=1), P4 (x=0.1, y=0.5), P5 (x=0.2, y=1.1), P6 (x=0.5, y=1.1), P7 (x=0.8, y=1.1), P8 (x=0.9, y=1.1), P9 (x=1, y=0); The normalized axial position range of the blade blades (3) of the second layer and above distributed on the surface of the turbine blade (1) is x = [-0.2, 0.2]. The non-uniform variation curve of the blade blade amplitude is determined according to the Bézier curve within the range of x = [-0.2, 0.2]. The curve control points are as follows: P 10 (x=-0.2,y=0), P 11 (x=-0.1,y=2.1), P 12 (x=0,y=2.1),P 13 (x=0.1, y=0), P 14 (x=0.2, y=0); Among them, y is the blade wing design amplitude control coefficient corresponding to the curve control point that varies non-uniformly with the normalized axial position.

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