CN114658595A - Wind turbine blade with leading edge extension power increasing device and design method thereof - Google Patents

Wind turbine blade with leading edge extension power increasing device and design method thereof Download PDF

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CN114658595A
CN114658595A CN202210284371.1A CN202210284371A CN114658595A CN 114658595 A CN114658595 A CN 114658595A CN 202210284371 A CN202210284371 A CN 202210284371A CN 114658595 A CN114658595 A CN 114658595A
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airfoil
increasing device
extension
original
blade
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虞小兵
张林伟
蔡安民
陈浩
彭阁
李林川
林伟荣
李力森
李媛
金强
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Huaneng Hubei New Energy Co ltd
Huaneng Clean Energy Research Institute
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Huaneng Clean Energy Research Institute
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D1/00—Wind motors with rotation axis substantially parallel to the air flow entering the rotor 
    • F03D1/06—Rotors
    • F03D1/0608—Rotors characterised by their aerodynamic shape
    • F03D1/0633—Rotors characterised by their aerodynamic shape of the blades
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G06F30/28—Design optimisation, verification or simulation using fluid dynamics, e.g. using Navier-Stokes equations or computational fluid dynamics [CFD]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2240/00—Components
    • F05B2240/20—Rotors
    • F05B2240/30—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
    • F05B2240/302—Segmented or sectional blades
    • G—PHYSICS
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    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2113/00—Details relating to the application field
    • G06F2113/06—Wind turbines or wind farms
    • G—PHYSICS
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    • G06F—ELECTRIC DIGITAL DATA PROCESSING
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    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/72—Wind turbines with rotation axis in wind direction

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Abstract

The invention belongs to the field of wind power generation, and relates to a wind turbine blade with a front edge extension power increasing device, which comprises an original blade airfoil, wherein the front edge of the original blade airfoil is additionally provided with the extension power increasing device, and the shape of the contact surface of the extension power increasing device and the front edge of the original blade airfoil is the same as the shape of the front edge of the original blade airfoil; the extension power increasing device is in a downward turning posture; the extension power increasing device and the original blade airfoil form a new airfoil shape, the lift coefficient of the new airfoil shape is larger than that of the original blade airfoil, and the resistance coefficient is smaller than that of the original blade airfoil. The relative thickness of the wing profile is reduced to improve the aerodynamic performance of the wing profile, increase the lift coefficient of the wing profile and reduce the drag coefficient; simultaneously, the chord length of the wing profile is increased, the stress area is increased, and the blade output is improved.

Description

Wind turbine blade with leading edge extension power increasing device and design method thereof
Technical Field
The invention belongs to the field of wind power generation, and relates to a wind turbine blade with a front edge extension power increasing device and a design method thereof.
Background
The wind turbine blade is used as a main part of a wind turbine generator system for capturing wind energy, and the quality of the pneumatic performance directly determines the wind energy conversion efficiency. When the blades are designed, the aerodynamic shape and aerodynamic performance of the blades are designed in priority, such as standard or corrected airfoil shape, chord length, torsion angle and pre-bending, when the aerodynamic performance reaches the optimal design, the structural design of the blades is started, and the structural shape of the blades is optimally designed through iterative optimization in order to meet the requirements of structural safety, noise control, trailing edge shedding vortex control and the like of the blades during the operation of a unit. The end result is to sacrifice part of the aerodynamic performance of the blade, while having to choose a medium thickness profile in the middle of the blade and a large thickness profile in the root. The direct effect of selecting large and medium thickness airfoils is an increase in the aerodynamic angle of attack where the flow is subject to separation.
At present, there are many methods for inhibiting airflow separation and further achieving work gain, and most of the common methods include a vortex generator for delaying or inhibiting stall occurrence, a gurney flap and a spoiler for improving trailing edge shedding vortex and increasing lift-drag ratio, and the like, improve the aerodynamic performance of an airfoil profile and a blade by adhering or mounting corresponding work gain accessories on the surface of the blade, and improve the capability of the blade for capturing wind energy. Therefore, aerodynamic optimal design and power increasing devices for the airfoil and the blade are always one of research hotspots in the aerodynamic category of the wind turbine generator.
In the above modes, the shape of the wing profile and the attack angle of the airflow flowing through the wing profile are not changed, the effect of inhibiting the airflow separation is realized by adopting the pneumatic accessories, and the power increasing effect is not obvious.
Disclosure of Invention
The invention aims to provide a wind turbine blade with a leading edge extension power increasing device and a design method thereof, and solves the problems that the pneumatic accessories are adopted to inhibit airflow separation, and the power increasing effect is not obvious.
The invention is realized by the following technical scheme:
a wind turbine blade with a front edge extension power increasing device comprises an original blade airfoil, wherein the front edge of the original blade airfoil is additionally provided with the extension power increasing device, and the shape of the contact surface of the extension power increasing device and the front edge of the original blade airfoil is the same as the shape of the front edge of the original blade airfoil;
the extension power increasing device is in a downward turning posture;
the extension power increasing device and the original blade airfoil form a new airfoil shape, the lift coefficient of the new airfoil shape is larger than that of the original blade airfoil, and the resistance coefficient is smaller than that of the original blade airfoil.
Further, the down-turning angle is theta, and theta is 0-15 degrees.
Furthermore, the distance between the most front edge of the extension power increasing device and the most front edge of the original blade airfoil is the extension length, and is marked as L, wherein L is (10-30%). c; c is the chord length of the original blade airfoil;
the formula of the relative thickness of the new airfoil after extension is as follows: ty ═ D/(L + c); d is the longest distance in the thickness direction of the wing of the original blade;
D＝Th*c，Ththe relative thickness of the original blade airfoil.
Further, the extension power increasing device is bonded or riveted on the wing-shaped front edge of the original blade;
the material of the extension power increasing device is the same as the original blade wing profile material, and the extension power increasing device is a prefabricated part.
Further, the extending work-increasing device is internally provided with a web.
The invention also discloses a design method of the wind turbine blade with the leading edge extension power increasing device, which comprises the following steps:
s1, selecting a blade mould as an original blade airfoil profile, and calculating the V-shaped profile of each section of the blade to be optimizedin～VrateWithin the wind speed, each wind speed ViAngle of attack alpha corresponding to each lower section positionnThe wind speed interval takes 1-2 m/s; vinIndicating cut-in wind speed, VrateRepresenting the wind speed corresponding to rated power;
s2, connecting the attack angle alpha of each sectionnForming a data set, and then calculating the standard deviation delta of the data set;
s3, selecting an airfoil angle of attack alpha under each wind speedn>Delta, simultaneously, taking the corresponding airfoil with the airfoil relative thickness range of 35-75% as the airfoil of the original blade;
s4, designing the aerodynamic shape of the extension power increasing device by a cubic Bezier curve method, and designing the extension length L of the foremost edge of the extension power increasing device and the foremost edge of the original blade airfoil, the downward turning angle theta of the extension power increasing device and the relative thickness Ty of the extended airfoil;
s5, adding an extension power increasing device on the wing-shaped front edge of the original blade, comparing the aerodynamic performance before and after the extension power increasing device is installed, and determining the optimal extension length L, downward turning angle theta and relative thickness T by iteratively optimizing the aerodynamic appearance of the extension power increasing devicey。
Further, the principle of iterative optimization satisfies the following conditions:
the lift coefficient of the new airfoil profile is greater than that of the original airfoil profile;
the resistance coefficient of the new airfoil profile is smaller than that of the original airfoil profile;
the aerodynamic attack angle of the new airfoil profile at each wind speed is not greater than that of the original airfoil profile at each wind speed;
the stalling attack angle range of the new airfoil profile is smaller than that of the original airfoil profile;
after the new wing section aerodynamic parameters replace the original wing section aerodynamic parameters, the calculated load of each section of the blade and the load of all key sections of the whole machine do not exceed the safety design requirement.
Further, in S4, the pneumatic profile of the extension power increasing device is a symmetric structure or an asymmetric structure, and the expression is:
B(t)＝P0(1-t)3+3P1t(1-t)2+3P2t2(1-t)+P3t3,t∈[0,1]；
in the formula P0、P1、P2、P3The four points define a cubic Bezier curve in a plane or a three-dimensional space; curve starting from P0Trend P1And from P2Comes to P3；P0And P1The distance between them determines the curve in turn to move towards P3Front, run towards P2The length of the curve in the direction.
Further, the lift coefficient C of the extended airfoillIncrease, coefficient of resistance CdAnd decreasing, wherein the lift-drag ratio is increased by the calculation formula:
Ct＝Cl sinφ-Cd cosφ
in the formula, phi is an inflow angle, phi is alpha + beta, alpha is a new airfoil attack angle, and beta is a new airfoil twist angle; clTo extend the lift coefficient after aerodynamic contouring, CdThe drag coefficient after extending the aerodynamic profile.
Further, increasing the chord length of the airfoil section of the blade is caused by M ^ c;
Figure BDA0003559460490000031
wherein M represents the torque at the cross-sectional position, ρ, B, v, a, a', w, cx,CtAnd r respectively represents air density, number of blades, wind speed, axial induction factor, tangential induction factor, rotation speed, chord length, tangential force coefficient and section position radius.
Compared with the prior art, the invention has the following beneficial technical effects:
the invention discloses a wind turbine blade with a leading edge extension power increasing device, which optimizes the profile of an airfoil profile, particularly a large and medium thickness airfoil profile, and improves the aerodynamic performance of the airfoil profile by installing an extension device at the leading edge of the airfoil profile. The principle is that after the extension device is installed, firstly, the chord length of the airfoil section is increased, and further, the stressed area of airflow flowing through the airfoil section is increased; and secondly, after the extension device is installed, the relative thickness of the wing profile is changed, and when airflow flows through the relatively thinner wing profile, the aerodynamic attack angle is reduced, so that the possibility of airflow separation is fundamentally weakened. The pneumatic power-increasing and resistance-reducing effects of the blades are realized by prolonging the chord length of the airfoil and reducing the relative thickness of the airfoil. The leading edge extension power increasing device is provided with a downward turning angle, the outer surface of the power increasing device is designed according to a cubic Bezier curve, and the inner surface of the power increasing device is consistent with the shape of the leading edge of the original airfoil. After the method is implemented, the maximum Cp of the blade and the annual generating capacity of the unit are increased, and the effect is good.
Drawings
FIG. 1 is a schematic cross-sectional view of an airfoil aerodynamic profile after installation of an extension power augmentation device;
FIG. 2 is a schematic perspective view of the aerodynamic profile of the airfoil with the extension power augmentation device installed;
FIG. 3 is a comparison of lift coefficients before and after installation of the extension power augmentation device;
FIG. 4 is a comparison of the drag coefficients before and after installation of the extension power augmentation device;
FIG. 5 is a comparison of blade Cp after installation of an extended work function augmentation device at the leading edge;
wherein, 1 is the extension increases merit device, 2 is former blade airfoil, 3 is the contact surface, 4 is the web, 5 is the girder.
Detailed Description
As shown in FIG. 1 and FIG. 2, the invention discloses a wind turbine blade with a leading edge extension power increasing device, comprising an original blade airfoil 2, wherein the leading edge of the original blade airfoil 2 is additionally provided with an extension power increasing device 1, and the shape of a contact surface 3 between the extension power increasing device 1 and the leading edge of the original blade airfoil 2 is the same as the shape of the leading edge of the original blade airfoil;
the extending power increasing device 1 is turned downwards, and a downward turning angle theta is 0-15 degrees;
the distance between the most front edge of the extension power increasing device 1 and the most front edge of the original blade airfoil 2 is the extension length, and is marked as L (10-30%); c is the chord length of the original blade airfoil 2;
the extension power increasing device 1 and the original blade airfoil 2 form a new airfoil shape, the lift coefficient of the new airfoil shape is larger than that of the original blade airfoil 2, and the drag coefficient is smaller than that of the original blade airfoil 2.
The blade airfoil comprises a suction surface and a pressure surface, and the longest distance between the connection starting point of the suction surface and the connection starting point of the pressure surface along the thickness direction of the airfoil is recorded as D;
D＝Th*c，Ththe relative thickness of the original blade airfoil 2, and c the chord length of the original blade airfoil 2.
Specifically, the extension work increasing device 1 is bonded or riveted on the front edge of the original blade airfoil 2.
Specifically, the material of the extension power increasing device 1 is the same as that of the original blade airfoil 2, and the extension power increasing device 1 is a prefabricated member.
Preferably, the structure of the extension work-increasing device 1 comprises a web plate 4 and a main beam 5, and the structural design of the web plate 4 and the main beam 5 needs to meet the requirement of structural safety; the shape of the extension work increasing device 1, including the values of the down-turned angle, the length and the curvature radius, must meet the structural safety requirements of each section of the blade.
The wind turbine captures wind energy through the wind wheel, the blades are used as main components of the wind wheel, and the quality of the pneumatic performance of the blades directly influences the wind energy capturing capacity of the wind turbine. The aerodynamic performance of the blade is determined by parameters such as airfoil distribution, airfoil aerodynamic performance, twist angle, chord length and pre-bending. In the design process of the blade, the root part of the blade is always provided with a large and medium thickness wing profile to ensure the structural safety of the blade, and the aerodynamic performance of the wing profile is lost, so that the power generation is lost. In addition, the large and medium thickness wing profiles are selected, so that the wing profiles are easy to generate air flow separation, stall and stall induced vibration.
The design method of the large and medium thickness airfoil leading edge extension power increasing device specifically comprises the following steps:
step 1: calculating the airfoil shape of each section of the blade to be optimized at V by adopting GH Bladed softwarein～VrateWithin the wind speed, each wind speed ViAngle of attack alpha corresponding to each lower section positionnThe wind speed interval takes 1-2 m/s; vinIndicating cut-in wind speed, VrateRepresenting the wind speed corresponding to the rated power;
step 2: angle of attack alpha of each cross sectionnForming a data set and then calculating the mean of the data set
Figure BDA0003559460490000051
And the standard deviation δ;
and step 3: selecting the wing attack angle alpha under each wind speedn>Delta, and the relative thickness range of the airfoil is within 35-75 percent of the corresponding airfoil;
and 4, step 4: the pneumatic appearance of the extended work increasing device 1 to be installed is designed by a cubic Bezier curve method, which can be symmetrical or asymmetrical, and the formula of the Bezier curve method follows:
B(t)＝P0(1-t)3+3P1t(1-t)2+3P2t2(1-t)+P3t3,t∈[0,1]
wherein the four points P0, P1, P2 and P3 define a cubic Bezier curve in a plane or in a three-dimensional space. The curve starts from P0 to P1 and goes from P2 to P3. The spacing between P0 and P1 determines the length of the curve that runs in the direction of P2 before turning to P3.
When designing the aerodynamic configuration of the extended power increasing device 1, the extension length L, the down-turning angle θ and the relative thickness T of the extended airfoil profile are determinedy，Ty＝D/(L+c)；
And 5: calculating and comparing the pneumatic performance before and after the installation of the extension power increasing device 1 through professional meshing software and CFD calculation software;
the aerodynamic shape of the extension power increasing device 1 is iteratively optimized, and the optimal extension length L, the optimal downward-turning angle theta and the optimal relative thickness T are determinedy；
The principle of determining whether it is optimal needs to be satisfied:
1) the lift coefficient of the new airfoil profile is greater than that of the original airfoil profile;
2) the resistance coefficient of the new airfoil profile is smaller than that of the original airfoil profile;
3) the aerodynamic attack angle of the new airfoil profile at each wind speed is not greater than that of the original airfoil profile at each wind speed;
4) the stalling attack angle range of the new airfoil profile is smaller than that of the original airfoil profile;
5) after the new wing section aerodynamic parameters replace the original wing section aerodynamic parameters, the calculated load of each section of the blade and the load of all key sections of the whole machine do not exceed the safety design requirement.
In the design process of the extension power increasing device 1, the structural appearance of the extension power increasing device is reasonably designed, so that the aerodynamic performance of the blade can be better improved, and the capability of capturing wind energy is improved. The power increasing effect of the leading edge extension power increasing device 1 is mainly reflected in that:
1) coefficient of lift ClIncrease of coefficient of resistance CdDecreasing, increasing the lift-drag ratio;
Ct＝Cl sinφ-Cd cosφ
in the formula, phi is an inflow angle, phi is alpha + beta, alpha is a new airfoil attack angle, and beta is a new airfoil twist angle.
2) Increasing the chord length of the airfoil section of the blade, due to M ^ c
Figure BDA0003559460490000071
Wherein M represents the torque at the cross-sectional position, ρ, B, v, a, a', w, cx,CtAnd r represents air density, number of blades, wind speed, axial direction, respectivelyInduction factor, tangential induction factor, rotation speed, chord length, tangential force coefficient and section position radius. The formula also illustrates that increasing chord length increases the rotor torque.
Taking a certain 40% airfoil as an example, the aerodynamic performance before and after the installation of the leading edge extension work increasing device 1 is subjected to CFD calculation analysis. The specific parameters are as follows: θ is 9 °; l is 280 mm; d is 400 mm; and c is 1000 mm.
The wing profiles are subjected to meshing and fluid simulation calculation through professional meshing software, so that lift coefficients and drag coefficients of the front and the rear parts of the installation extension device when the attack angle is from 0 to 32 degrees and the step length is 2 degrees are obtained, and the results are shown in table 1.
TABLE 1 comparison of lift drag coefficients of front and rear wing sections of installed extension power increasing device
Figure BDA0003559460490000072
Figure BDA0003559460490000081
The corresponding lift coefficient is compared with that of the original airfoil profile to form a new airfoil profile, as shown in fig. 3 and 4, the corresponding lift coefficient is larger than that of the original airfoil profile, and the resistance coefficient is smaller than that of the original airfoil profile.
The method is characterized in that a power increasing device of an extension section is installed at a 3-8 m section position of a blade of a certain 1.5MW unit through calculation of special simulation software GH Bladed of a wind turbine load, and comparison of power factors Cp of the blade before and after installation is shown in figure 5.
After the extension work-increasing device 1 is installed at the position 3-8 m of the section of the blade, the blade Cp is lifted to 0.488 from 0.483, and the lifting proportion is 1.03%. The influence on the annual power generation capacity of the wind power plant under different annual average wind speeds is shown in table 2. The Weibull wind frequency distribution k value was calculated to be 2.
TABLE 2 generated energy increasing quantity before and after installing the extension power increasing device
Annual average wind speed [ m/s ]] Annual power generation capacity increasing amount-]
4 0.92％
4.5 0.85％
5 0.78％
5.5 0.71％
6 0.64％
6.5 0.57％
7 0.51％
After the extending power increasing device 1 is installed on the front edge, the aerodynamic performance of the blade is improved well, and the annual generated energy is increased by 0.51% -0.92% when the annual average wind speed is 4-7 m/s.
The invention provides a large and medium thickness wing section leading edge extension power increasing device and method for a wind turbine, which realize the pneumatic power increasing and resistance reducing effects of blades by prolonging the chord length of the wing section and reducing the relative thickness of the wing section. The leading edge extension power increasing device 1 is provided with a downward turning angle, the outer surface of the power increasing device is designed according to a cubic Bezier curve, and the inner surface of the power increasing device is consistent with the shape of the leading edge of the original airfoil. After the method is implemented, the maximum Cp of the blade and the annual generating capacity of the unit are increased, and the effect is good.
According to the invention, the extension power increasing device 1 is arranged at the front edge of the wing profile, so that the relative thickness of the wing profile is reduced, the aerodynamic performance of the wing profile is improved, the lift coefficient of the wing profile is increased, and the drag coefficient is reduced; and secondly, the power increasing device 1 is extended, the chord length of the wing profile is increased, the stress area is increased, and the blade output is improved.

Claims (10)

1. A wind turbine blade with a front edge extension power increasing device is characterized by comprising an original blade airfoil (2), wherein the front edge of the original blade airfoil (2) is provided with the extension power increasing device (1), and the shape of a contact surface (3) of the extension power increasing device (1) and the front edge of the original blade airfoil (2) is the same as the shape of the front edge of the original blade airfoil;
the extension power increasing device (1) is in a downward turning posture;
the extension power increasing device (1) and the original blade airfoil (2) form a new airfoil shape, the lift coefficient of the new airfoil shape is larger than that of the original blade airfoil (2), and the drag coefficient is smaller than that of the original blade airfoil (2).
2. The wind turbine blade with the leading edge extension power increasing device as claimed in claim 1, wherein the down-turning angle is θ, and θ is 0-15 °.
3. The wind turbine blade with the leading edge extension power increasing device according to claim 1, wherein the distance between the most leading edge of the extension power increasing device (1) and the most leading edge of the original blade airfoil (2) is the extension length, which is marked as L (10% -30%); c is the chord length of the original blade airfoil (2);
the formula of the relative thickness of the new airfoil after extension is as follows: ty ═ D/(L + c); d is the longest distance in the thickness direction of the original blade airfoil (2);
D＝Th*c，This the relative thickness of the original blade airfoil (2).
4. Wind turbine blade with leading edge extension work increasing device according to claim 1, characterized in that the extension work increasing device (1) is bonded or riveted to the leading edge of the original blade airfoil (2);
the material of the extension work increasing device (1) is the same as that of the original blade airfoil (2), and the extension work increasing device (1) is a prefabricated part.
5. A wind turbine blade with a leading edge extension power increase device according to claim 1, characterised in that the extension power increase device (1) is internally provided with a web (4).
6. The method for designing a wind turbine blade with a leading edge extension power increasing device as claimed in any one of claims 1 to 5, comprising the steps of:
s1, selecting a blade mould as an original blade airfoil (2), and calculating the V-shaped section airfoil of the blade to be optimizedin～VrateWithin the wind speed, each wind speed ViAngle of attack alpha corresponding to each lower section positionnThe wind speed interval takes 1-2 m/s; vinIndicating cut-in wind speed, VrateRepresenting the wind speed corresponding to the rated power;
s2, connecting the attack angle alpha of each sectionnForming a data set, and then calculating the standard deviation delta of the data set;
s3, selecting an airfoil angle of attack alpha under each wind speedn>Delta, simultaneously, taking the corresponding airfoil with the relative thickness range of the airfoil within 35-75 percent as the original blade airfoil (2);
s4, designing the aerodynamic shape of the extension work increasing device (1) by a cubic Bezier curve method, and designing the extension length L of the most front edge of the extension work increasing device (1) and the most front edge of the original blade airfoil (2), the downward turning angle theta of the extension work increasing device (1) and the relative thickness Ty of the airfoil after extension;
s5, adding the extension power increasing device (1) at the front edge of the original blade airfoil (2), comparing the pneumatic performance before and after the extension power increasing device (1) is installed, and determining the optimal extension length L, downward turning angle theta and relative thickness T by iteratively optimizing the pneumatic appearance of the extension power increasing device (1)y。
7. The method for designing a wind turbine blade with a leading edge extension power increasing device as claimed in claim 6, wherein the principle of iterative optimization satisfies the following conditions:
the lift coefficient of the new airfoil profile is greater than that of the original airfoil profile;
the resistance coefficient of the new airfoil profile is smaller than that of the original airfoil profile;
the aerodynamic attack angle of the new airfoil profile at each wind speed is not greater than that of the original airfoil profile at each wind speed;
the stalling attack angle range of the new airfoil profile is smaller than that of the original airfoil profile;
after the new wing section aerodynamic parameters replace the original wing section aerodynamic parameters, the calculated load of each section of the blade and the load of all key sections of the whole machine do not exceed the safety design requirement.
8. The method for designing a wind turbine blade with a leading edge extended work increasing device according to claim 6, wherein in S4, the aerodynamic profile of the extended work increasing device (1) is a symmetric structure or an asymmetric structure, and the expression is as follows:
B(t)＝P0(1-t)3+3P1t(1-t)2+3P2t2(1-t)+P3t3,t∈[0,1]；
in the formula P0、P1、P2、P3The four points define a cubic Bezier curve in a plane or a three-dimensional space; curve starting from P0Trend P1And from P2Comes to P3；P0And P1The distance between them determines the curve in turn to move towards P3Front, run towards P2The length of the curve in the direction.
9. The method of claim 6, wherein the lift coefficient C of the extended airfoil profile is greater than the lift coefficient C of the extended airfoil profilelIncrease of coefficient of resistance CdAnd decreasing, wherein the lift-drag ratio is increased by the calculation formula:
Ct＝Cl sinφ-Cd cosφ
in the formula, phi is an inflow angle, phi is alpha + beta, alpha is a new airfoil attack angle, and beta is a new airfoil twist angle; clTo extend the lift coefficient after aerodynamic contouring, CdThe drag coefficient after extending the aerodynamic profile.
10. The method for designing a wind turbine blade with a leading edge extension power increasing device as claimed in claim 6, wherein when the chord length of the airfoil section of the blade is increased, M ℃.;
Figure FDA0003559460480000031
wherein M represents the torque at the cross-sectional position, ρ, B, v, a, a', w, cx,CtAnd r respectively represents air density, number of blades, wind speed, axial induction factor, tangential induction factor, rotation speed, chord length, tangential force coefficient and section position radius.
CN202210284371.1A 2022-03-22 2022-03-22 Wind turbine blade with leading edge extension power increasing device and design method thereof Pending CN114658595A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115649417A (en) * 2022-12-14 2023-01-31 中国空气动力研究与发展中心空天技术研究所 High subsonic speed self-balancing high stealth airfoil profile

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115649417A (en) * 2022-12-14 2023-01-31 中国空气动力研究与发展中心空天技术研究所 High subsonic speed self-balancing high stealth airfoil profile

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