CN103321853B - But utilize the pneumatic equipment blades made of compound damping structure to quiver method - Google Patents

Abstract

But the present invention is specially a kind of pneumatic equipment blades made of compound damping structure that utilizes to quiver method, solves large-scale flexible blade and easily flutter occurs and lack the problem of effectively preventing method.But utilize the pneumatic equipment blades made of compound damping structure to quiver method, be specially and establish co-curing restriction damping layer at blade surface, establish vector free axis method at girder outer surface; Vector free axis method is made up of individual layer damping material, selects damping viscoelastic material or damping alloy or damp composite material; By composite layer and damping material interlayer mistake, co-curing restriction damping layer arranges that co-curing is shaping, composite layer selects that glass fiber compound material or carbon fiber composite or glass and carbon fiber are mixed takes composite material, and Damping material layer selects damping viscoelastic material.But the present invention compared with prior art has general applicability, effectively quivering property, Economy, designability.

Description

But utilize the pneumatic equipment blades made of compound damping structure to quiver method

Technical field

The present invention relates to technical field of wind power generation, but being specially a kind of pneumatic equipment blades made of compound damping structure that utilizes quivers method.

Background technique

Along with environmental problem is more and more subject to people's attention, clean energy resource progressively becomes the main flow of world energy sources development.Wind energy was obtaining develop rapidly in recent years as a kind of renewable and clean energy resource, and wherein MW level wind energy conversion system has become the mainstream model of wind energy conversion system.For meeting the high-power output requirement of wind energy conversion system, pneumatic equipment blades made is towards maximization, thin-long development (single length of blade that such as certain company external produces has reached 55 meters).There is flutter in large-scale slender blade, its main flutter form has the span vibrate (edgwisevibration) and pat vibration (flapwisevibration) under the complex load effect of aerodynamic force, elastic force and inertial force.The flutter of blade not only reduces the power stage of wind wheel, the more important thing is that the alternating stress of blade flutter can make blade produce fatigue crack and even rupture; Flutter Blades and air effect produce aerodynamic noise in addition, cause noise pollution to environment, have influence on the life of the resident near wind energy turbine set and the normal activity of other animals.

For blade noise, existing solution mainly contains:

Patent (CN101619705B) discloses a kind of Blades For Horizontal Axis Wind with bionic-type blade top boss, this blade can improve the flow losses at blade tip place, thus the noise that reduction pneumatic equipment blades made and tip vortex are interfered mutually, reach the object to whole wind wheel noise reduction.

Patent (CN102003333A) discloses a kind of pneumatic equipment blades made with decrease of noise functions, and the profile line undulate of this blade tip part, transition portion and trailing edge part is also provided with toothed segment.

Patent (CN102562436A) discloses a kind of Denoiser of wind turbine rotor blade, and this Denoiser contains bristle, hair race and porous layer.This Denoiser can have good noise reduction to the blade in the distinguished and admirable situation of different direction.

Patent (EP0652367) discloses a kind of pneumatic equipment blades made with dissimilar tooth form trailing edge; Patent (EP1314885) discloses a kind of pneumatic equipment blades made with profile of tooth panel; Patent (EP1338793) discloses a kind of pneumatic equipment blades made with variable profile of tooth trailing edge.

Such scheme all changes blade tip shape, improves blade tip gas flow shape with different tooth profile, thus reaches noise reduction object.But the profile of tooth blade tip difficulty of processing in such scheme is comparatively large, and change the aerodynamic configuration of former aerofoil profile, its overall pneumatic ability is still to be tested.

For blade flutter, existing solution mainly contains:

Patent (CN102322391A) discloses a kind of guard method pneumatic equipment blades made vibration condition being carried out to forecast analysis, according to the hour of danger of computational prediction blade, and shuts down in advance dangerous blade, reaches the protection to blade.This method can carry out available protecting to blade, but but do not improve blade self and to quiver ability, improve the stability of blade.

Patent (CN2737980Y) and patent (CN102348892A) individually disclose a kind of structural damping device of wind wheel blade, this damper invests blade inwall by the mode such as bonding, in wider frequency of okperation, effectively can control blade vibration, but there is damper disengaging, increase leaf quality with the defect of complex structure etc.

In sum, but the research of quivering for large-scale blade at present mainly concentrates on Pneumatic method and extra damper method.Pneumatic method mainly utilizes the aerodynamic configuration changing blade, make it that there is good stall performance, but thus reach the object of quivering in high wind speed district, but the method can reduce the dynamics ability of blade, thus reduce the output power of wind wheel, but and poor in the effect of quivering in Zhong Di wind speed district; Extra damper method utilizes on blade, to arrange extra damper realize to blade flutter suppression, but only work at certain frequency domain or a certain flutter direction, and blade can be made to increase additional mass, and damper easily comes off in addition, causes potential safety hazard.

Summary of the invention

Easily there is flutter to solve wind energy conversion system large-scale flexible blade and lack the problem of effectively preventing method in the present invention, but providing a kind of pneumatic equipment blades made of compound damping structure that utilizes quivers method.

The present invention adopts following technological scheme to realize: but utilize the pneumatic equipment blades made of compound damping structure to quiver method, be specially and establish co-curing restriction damping layer at blade surface, establish vector free axis method at girder outer surface; Vector free axis method is by individual layer damping viscoelastic material or individual layer damping alloy or individual layer damp composite material, and be specially and adhere to girder outer surface, wherein the thickness of vector free axis method can be calculated by following formula:

Wherein for main beam structure fissipation factor, for girder thickness, for damping layer thickness, for girder Young's modulus, for damping material Young's modulus, for damping material fissipation factor;

By composite layer and damping material interlayer mistake, co-curing restriction damping layer arranges that (being specially the staggered superposition of one deck composite layer one deck Damping material layer) co-curing is shaping, and the superiors and orlop are composite layer, Damping material layer at least establishes one deck, composite layer selects that glass fiber compound material or carbon fiber composite or glass and carbon fiber are mixed takes composite material, and Damping material layer selects damping viscoelastic material; The thickness of co-curing restriction damping layer can be calculated by following various simultaneous method of iteration:

Wherein for covering co-curing restriction damping layer Structural parameter, lfor the thickness of composite layer, lfor the total thickness of co-curing restriction damping layer, nfor the Damping material layer number of plies, h _v for damping material layer thickness; βfor Damping material layer fissipation factor; gfor the shear modulus of damping material; fthe excited frequency of fluid-load (wind carries) suffered by blade; wfor the quality of co-curing restriction damping layer unit length; gfor gravity accleration; a _i be ithe area of layer composite layer; e _i be ithe Young's modulus of layer composite layer; d _i for first layer composite layer is to ithe distance of layer composite layer; i _i be ilayer composite layer for the moment of inertia of its neutral surface, neutral surface refer to structure bend vibration time both do not had pulling force do not have yet the face of pressure (neutral surface refer to structure bend vibration time both do not had pulling force there is no the face of pressure yet); k _i be ithe tensible rigidity of the composite layer of layer, (EI) _∞ for the flexural rigidity of co-curing restriction damping layer neutral surface; (EI) ₀ for each composite layer is with the summation of self neutral surface calculating flexural rigidity; (EI) _r for the flexural rigidity real part of co-curing restriction damping layer. refor getting real part, imfor getting imaginary part, for amount of transition, i, j, efor counting variable, rfor the intermediate quantity of computational algorithm.

Of the present inventionly establish co-curing restriction damping layer at blade surface, establish vector free axis method specifically to have employed the shaping processing technology of co-curing at girder outer surface, this is that forming materials those skilled in the art know.Above-mentionedly determine that the method for co-curing restriction damping layer and free damping layer thickness is founding mathematical models on the basis of great many of experiments, adopt rational calculation process, utilize suitable numerical simulation to draw, this method can describe the relation in the thickness of co-curing restriction damping layer and vector free axis method and vane design of wind turbines process between other parameters more exactly. for main beam structure fissipation factor, for covering co-curing restriction damping layer Structural parameter, this is that designing requirement determined; In above-mentioned design process, all the other each parameters are the known parameters in vane design of wind turbines process, as girder thickness, girder Young's modulus, damping material Young's modulus, damping material fissipation factor etc., it is facile to be that those skilled in the art hold in different design processes.

Beneficial effect of the present invention is as follows: utilize detailed project navigator to the addition of co-curing restriction damping layer and vector free axis method for pneumatic equipment blades made, but achieve quivering of wind energy conversion system.The present invention compared with prior art has:

1) general applicability.Because the present invention mainly carries out relevant impedance bundary to blade interior structure, blade aerodynamic profile is not modified, and blade root adopts traditional approach with linking of wind wheel hub.Therefore the present invention can be suitable for the apparatus for lower wind machine wind wheel of most circumstances.

2) but effective quivering property.The present invention adopts the co-curing damping-constraining Rotating fields of composite material+damping material+composite material to blade covering, girder adopts free damping layer structure, therefore compound damping structure blade has higher Structural parameter, effectively can suppress blade flutter in wider frequency domain, improve the aerodynamic stability of wind mill wind wheel.

3) Economy.Co-curing damping and free damping process can not significantly increase blade cost of production, but therefore the present invention has certain Economy in the better performance of quivering of acquisition simultaneously.

4) designability.Can design damping parameter according to actual needs and optimize, the blade structure fissipation factor needed for acquisition, meet design needs.

Accompanying drawing explanation

Fig. 1 is blade section structural representation;

Fig. 2 is co-curing restriction damping layer structural representation.

In figure: 1-blade, 2-vector free axis method, 3-co-curing restriction damping layer, 4 girders, 5-composite layer, 6-Damping material layer.

Embodiment

But utilize the pneumatic equipment blades made of compound damping structure to quiver method, be specially and establish co-curing restriction damping layer 3 on blade 1 surface, establish vector free axis method 2 at girder 4 outer surface; Vector free axis method 2 is by individual layer damping viscoelastic material or individual layer damping alloy or individual layer damp composite material, and be specially and adhere to girder outer surface, wherein the thickness of vector free axis method can be calculated by following formula:

Wherein for main beam structure structure fissipation factor, for girder thickness, for damping layer thickness, for girder Young's modulus, for damping material Young's modulus, for damping material fissipation factor;

By composite layer and damping material interlayer mistake, co-curing restriction damping layer 3 arranges that co-curing is shaping, and the superiors and orlop are composite layer, Damping material layer at least establishes one deck, composite layer selects that glass fiber compound material or carbon fiber composite or glass and carbon fiber are mixed takes composite material, and Damping material layer selects damping viscoelastic material; The thickness of co-curing restriction damping layer 3 can be calculated by following various simultaneous method of iteration:

Wherein for covering co-curing restriction damping layer Structural parameter, lfor composite layer thickness, lfor co-curing total structure thickness, nfor the Damping material layer number of plies, h _v for damping material layer thickness; βfor Damping material layer fissipation factor; gfor the shear modulus of damping material; _f the excited frequency of fluid-load (wind carries) suffered by blade; wfor the quality of co-curing restriction damping layer unit length; gfor gravity accleration; a _i be ithe area of layer composite layer; e _i be ithe Young's modulus of layer composite layer; d _i for first layer composite layer is to ithe distance of layer composite layer; i _i be ilayer composite layer for the moment of inertia of its neutral surface, neutral surface refer to structure bend vibration time both do not had pulling force there is no the face of pressure yet; k _i be ithe tensible rigidity of the composite layer of layer, (EI) _∞ for the flexural rigidity of co-curing restriction damping layer neutral surface; (EI) ₀ for each composite layer is with the summation of self neutral surface calculating flexural rigidity; (EI) _r for the flexural rigidity real part of co-curing restriction damping layer.

In specific implementation process, between girder 4 outer surface and vector free axis method 2, establish expansion change layer, expand change layer and select the inner rigid foam for spherical cavity structure, or select the material of the internal cellular shape structure be made up of metal or macromolecular material.

Embodiment 1

With certain 2500kW wind energy conversion system for embodiment.This wind energy conversion system is mainly used in marine wind electric field, and its design power is 2.5MW, and adopt Three-blade form, leaf covering sheet material is GRP, I-steel girder, planetary pinion speedup, double loop asynchronous motor, Air flow; Its main design parameters is as table 1.

Table 1 main design parameters

(1) aerofoil profile is selected

According to designing requirement, whole lamina selects NACA6413 aerofoil profile, and this aerofoil profile has larger ratio of lift coefficient to drag coefficient and good stall performance.

(2) damping structure

Adopt the co-curing damping-constraining Rotating fields of composite material, damping material, composite material; Steel I-beam selected by girder, and does vector free axis method process, is pasted onto on girder web plate by damping material epoxy resin.Damping material all selects epoxy resin viscoelastic material (SMRD100F50), its fissipation factor β=0.89, and the temperature that 120 DEG C can be born for a long time, meet the working condition requirement of large scale wind power machine blade.

(3) but quiver specificity analysis

At Matlab/Simulink environment, modeling is carried out to this pneumatic equipment blades made.Co-curing restriction damping layer performance parameter is: E ₁₁=42.6GPa, E ₁₂=16.5GPa, G ₁₂=5.5GPa, ν ₁₂=0.22, ρ=1950kg/m ^-3.Damping property parameter is: β=0.89, G=3.43 × 10 ⁶n/m, E=1.14 × 10 ⁶n/m, ignores the temperature effect frequently of damping material.Based on ONERA nonlinear aerodynamic model to common blade and damping vane at threshold wind velocity v ₁ =4m/s, rated wind speed v ₂ =15m/s, shutdown wind speed v ₃ =25m/s and survival wind speed v ₄ numerical simulation contrast is carried out under=45m/s tetra-kinds of wind speed.The structural damping of simulation process common blade is ignored.Table 2 is the performance comparison of common blade and damping vane under each operating mode.

Table 2 correlation data

Calculate the Structural parameter of damping vane under four kinds of wind speed by emulated data and formula (23) to be respectively η ₁=0.617, η ₂=0.579, η ₃=0.523 He η ₄=0.439.From table 2, under four kinds of wind speed, damping vane does not reduce 51.1%, 48.1%, 43.6%, 37.1% than the shimmy shift standards difference of common blade, and shimmy velocity standard difference does not reduce 51.1%, 47.9%, 43.7%, 37.1%; Wave shift standards difference and do not reduce 37.9%, 34.8%, 30.8%, 25.2%, wave velocity standard difference and do not reduce 37.9%, 35.0%, 30.8%, 25.0%.

In sum, part flutter can be converted into thermal energy consumption by rubbing in damping material and dissipate by damping vane, blade is patted to flutter, opened up and can effectively suppress to flutter and torsional flutter, but significantly improving blade self quivers ability, gives full play to the advantage of flexible blade.

Claims (2)

1. but one kind utilizes the pneumatic equipment blades made of compound damping structure to quiver method, it is characterized in that: be specially and establish co-curing restriction damping layer (3) on blade (1) surface, establish vector free axis method (2) at girder (4) outer surface; Vector free axis method (2) is individual layer damping viscoelastic material or individual layer damping alloy or individual layer damp composite material, and be specially and adhere to girder (4) outer surface, wherein the thickness of vector free axis method is calculated by following formula:

$\left\{\begin{array}{c}{\mathrm{\η}}_1=\frac{eh(3+6h+4h^2)}{1+eh(5+6h+4h^2)}\mathrm{\β}\\ h=\frac{H_2}{H_1}\\ e=\frac{E_2}{E_1}\end{array}\right.$

Wherein η ₁for main beam structure fissipation factor, H ₁for girder thickness, H ₂for damping layer thickness, E ₁for girder Young's modulus, E ₂for damping material Young's modulus, β is damping material fissipation factor;

By composite layer and damping material interlayer mistake, co-curing restriction damping layer (3) arranges that co-curing is shaping, and the superiors and orlop are composite layer, Damping material layer at least establishes one deck, composite layer selects that glass fiber compound material or carbon fiber composite or glass and carbon fiber are mixed takes composite material, and Damping material layer selects damping viscoelastic material; The composite layer of co-curing restriction damping layer (3) and the thickness of Damping material layer are calculated by following various simultaneous method of iteration:

${\mathrm{\η}}_2=\frac{\mathrm{Im}{\left(ET\right)}^{*}}{\mathrm{Re}{\left(EI\right)}^{*}}=\frac{\mathrm{Im}\left(Z^{*}\right)Y}{1+\mathrm{Re}\left(Z^{*}\right)Y}$

$\left\{\begin{array}{c}{X}_1^{*}=\frac{{\mathrm{bG}}^{*}}{H_v{K}_T{p}^2}\\ G^{*}=G(1+j\mathrm{\β})\end{array}\right.$

$\left\{\begin{array}{c}{p}^2=2\mathrm{\π}f\sqrt{\frac{W}{g{\left(EI\right)}_r}}\\ {\left(EI\right)}_r=\mathrm{Re}{\left(EI\right)}^{*}={\left(EI\right)}_0\[1+\mathrm{Re}\left(Z^{*}\right)Y\]\end{array}\right.$

$\left\{\begin{array}{c}\left(\frac{1}{K_T^2\underset{j=i}{\overset{N}{\Σ}}{K}_i}\right)(\underset{e=2}{\overset{N}{\Σ}}\[\left(\underset{m=e}{\overset{N}{\Σ}}{K}_m\right)R_e\])-\frac{1}{K_T}\{\left(\underset{j=1}{\overset{N}{\Σ}}{K}_i\right)\left(\underset{j=2}{\overset{i}{\Σ}}{R}_j\right)+\underset{j=i+1}{\overset{N}{\Σ}}\[(\underset{e=j}{\overset{N}{\Σ}}{K}_e)R_j\]\}-X_1^{*}{R}_i\\ =\frac{1}{K_T^2{H}_v}\left(\underset{j=i}{\overset{N}{\Σ}}{K}_i\right)\left(\underset{i=2}{\overset{N}{\Σ}}{K}_i{d}_i\right)-\frac{1}{K_T{H}_v}\left(\underset{j=i}{\overset{N}{\Σ}}{K}_i{d}_i\right)\\ K_T={\mathrm{\ΣK}}_i\end{array}\right.$

$Z^{*}=1-\frac{H_v}{{\left(EI\right)}_r}\underset{i=2}{\overset{N}{\Σ}}\left\{K_i{d}_i\[\underset{j=2}{\overset{i}{\Σ}}{R}_j-\frac{1}{K_T}\underset{j=2}{\overset{i}{\Σ}}\[\left(\underset{e=i}{\overset{N}{\Σ}}{K}_e\right)R_j\]\]\right\}$

$D=\frac{{\mathrm{\ΣE}}_i{A}_i{d}_i}{{\mathrm{\ΣE}}_i{A}_i}$

(EI) _∞＝ΣE _iA _i(d _i-D) ²+ΣE _iI _i

(EI) ₀＝ΣE _iI _i

$Y=\frac{{\left(EI\right)}_r}{{\left(EI\right)}_0}=\frac{{\left(EI\right)}_{\mathrm{\∞}}}{{\left(EI\right)}_0}-1$

$l=\frac{L-(N-1)H_v}{N}$

Wherein η ₂for the Structural parameter of co-curing restriction damping layer, l is the thickness of composite layer, and L is the total thickness of co-curing restriction damping layer, and N is the composite layer number of plies, H _vfor damping material layer thickness; β is Damping material layer fissipation factor; G is the shear modulus of damping material; The excited frequency that f carries for blade institute wind-engaging; W is the quality of co-curing restriction damping layer unit length; G is gravity accleration; A _iit is the area of i-th layer of composite layer; E _iit is the Young's modulus of i-th layer of composite layer; d _ifor the distance of outermost surface composite layer to the i-th layer composite layer; I _ibe the moment of inertia of i-th layer of composite layer for its neutral surface, K _iit is the tensible rigidity of the composite layer of i-th layer; (EI) _∞for the flexural rigidity of co-curing restriction damping layer neutral surface; (EI) ₀for each composite layer is with the summation of self neutral surface calculating flexural rigidity; (EI) _rfor the flexural rigidity real part of co-curing restriction damping layer.

2. but the pneumatic equipment blades made of compound damping structure that utilizes according to claim 1 quivers method, it is characterized in that: between girder (4) outer surface and vector free axis method (2), establish expansion change layer, expand change layer and select the inner rigid foam for spherical cavity structure, or select the material of the internal cellular shape structure be made up of metal or macromolecular material.