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Influence of Reynolds Number on Multi-Objective Aerodynamic Design of a Wind Turbine Blade.

Ge M, Fang L, Tian D - PLoS ONE (2015)

Bottom Line: To make the study more general, two kinds of multi-objective optimization are involved: one is based on the maximum power coefficient (CPopt) and the ultimate load, and the other is based on the ultimate load and the annual energy production (AEP).It is found that under the same configuration, the optimal design has a larger CPopt or AEP (CPopt//AEP) for the same ultimate load, or a smaller load for the same CPopt//AEP at higher Reynolds number.At a certain tip-speed ratio or ultimate load, the blade operating at higher Reynolds number should have a larger chord length and twist angle for the maximum Cpopt//AEP.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing, P. R. China.

ABSTRACT
At present, the radius of wind turbine rotors ranges from several meters to one hundred meters, or even more, which extends Reynolds number of the airfoil profile from the order of 105 to 107. Taking the blade for 3MW wind turbines as an example, the influence of Reynolds number on the aerodynamic design of a wind turbine blade is studied. To make the study more general, two kinds of multi-objective optimization are involved: one is based on the maximum power coefficient (CPopt) and the ultimate load, and the other is based on the ultimate load and the annual energy production (AEP). It is found that under the same configuration, the optimal design has a larger CPopt or AEP (CPopt//AEP) for the same ultimate load, or a smaller load for the same CPopt//AEP at higher Reynolds number. At a certain tip-speed ratio or ultimate load, the blade operating at higher Reynolds number should have a larger chord length and twist angle for the maximum Cpopt//AEP. If a wind turbine blade is designed by using an airfoil database with a mismatched Reynolds number from the actual one, both the load and Cpopt//AEP will be incorrectly estimated to some extent. In some cases, the assessment error attributed to Reynolds number is quite significant, which may bring unexpected risks to the earnings and safety of a wind power project.

No MeSH data available.


Related in: MedlinePlus

Distributions of (A) α and (B) Cl/Cd for designs of O, P, Q and R at the corresponding λopt.
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pone.0141848.g014: Distributions of (A) α and (B) Cl/Cd for designs of O, P, Q and R at the corresponding λopt.

Mentions: Fig 14 shows the distribution of α and Cl/Cd for O, P, Q and R at the corresponding λopt. Different from the optimization based on CPopt, both the operating α and Cl/Cd show a certain degree of deviation from the optimal conditions. Generally, at λopt, the blade element operates at an angle of attack that is a little smaller than the optimal conditions, and thereby a smaller Cl/Cd. Fig 15 shows the distribution of chord length and twist angle for the four design points. A similar trend as Fig 8 can be observed. For the smaller operating Cl of Q, the chord length of Q is about 10% larger than P. In comparison with O, R can achieve a reduction in chord length of about 9%. As shown in Fig 15B, for the larger operating angle of attack at smaller Reynolds number, the twist angle of P is about 1.0 degree smaller than Q, and the twist angle of R is about 0.8 degree smaller than O.


Influence of Reynolds Number on Multi-Objective Aerodynamic Design of a Wind Turbine Blade.

Ge M, Fang L, Tian D - PLoS ONE (2015)

Distributions of (A) α and (B) Cl/Cd for designs of O, P, Q and R at the corresponding λopt.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4631510&req=5

pone.0141848.g014: Distributions of (A) α and (B) Cl/Cd for designs of O, P, Q and R at the corresponding λopt.
Mentions: Fig 14 shows the distribution of α and Cl/Cd for O, P, Q and R at the corresponding λopt. Different from the optimization based on CPopt, both the operating α and Cl/Cd show a certain degree of deviation from the optimal conditions. Generally, at λopt, the blade element operates at an angle of attack that is a little smaller than the optimal conditions, and thereby a smaller Cl/Cd. Fig 15 shows the distribution of chord length and twist angle for the four design points. A similar trend as Fig 8 can be observed. For the smaller operating Cl of Q, the chord length of Q is about 10% larger than P. In comparison with O, R can achieve a reduction in chord length of about 9%. As shown in Fig 15B, for the larger operating angle of attack at smaller Reynolds number, the twist angle of P is about 1.0 degree smaller than Q, and the twist angle of R is about 0.8 degree smaller than O.

Bottom Line: To make the study more general, two kinds of multi-objective optimization are involved: one is based on the maximum power coefficient (CPopt) and the ultimate load, and the other is based on the ultimate load and the annual energy production (AEP).It is found that under the same configuration, the optimal design has a larger CPopt or AEP (CPopt//AEP) for the same ultimate load, or a smaller load for the same CPopt//AEP at higher Reynolds number.At a certain tip-speed ratio or ultimate load, the blade operating at higher Reynolds number should have a larger chord length and twist angle for the maximum Cpopt//AEP.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing, P. R. China.

ABSTRACT
At present, the radius of wind turbine rotors ranges from several meters to one hundred meters, or even more, which extends Reynolds number of the airfoil profile from the order of 105 to 107. Taking the blade for 3MW wind turbines as an example, the influence of Reynolds number on the aerodynamic design of a wind turbine blade is studied. To make the study more general, two kinds of multi-objective optimization are involved: one is based on the maximum power coefficient (CPopt) and the ultimate load, and the other is based on the ultimate load and the annual energy production (AEP). It is found that under the same configuration, the optimal design has a larger CPopt or AEP (CPopt//AEP) for the same ultimate load, or a smaller load for the same CPopt//AEP at higher Reynolds number. At a certain tip-speed ratio or ultimate load, the blade operating at higher Reynolds number should have a larger chord length and twist angle for the maximum Cpopt//AEP. If a wind turbine blade is designed by using an airfoil database with a mismatched Reynolds number from the actual one, both the load and Cpopt//AEP will be incorrectly estimated to some extent. In some cases, the assessment error attributed to Reynolds number is quite significant, which may bring unexpected risks to the earnings and safety of a wind power project.

No MeSH data available.


Related in: MedlinePlus