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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

Results of the second kind of mismatched design based on the ultimate Mxy-r and CPopt.(A) Pareto frontiers of the mismatched design and the practical operating assessment, (B) excursion of the practical operating CPopt and Mxy-r from the mismatched design values
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pone.0141848.g018: Results of the second kind of mismatched design based on the ultimate Mxy-r and CPopt.(A) Pareto frontiers of the mismatched design and the practical operating assessment, (B) excursion of the practical operating CPopt and Mxy-r from the mismatched design values

Mentions: To study the second kind of mismatched design, a wind turbine rotor practically running at Re = 6×106 is designed using the airfoil database at Re = 3×106. Fig 18 shows results of the second mismatched design based on the ultimate Mxy-r and CPopt. Similarly, on one hand, due to the Reynolds number effect on airfoil, the performance of the airfoils with the correct Reynolds number is better than the airfoil database used, while on the other hand, due to the mismatched airfoil database, the design deviates from the optimal shape. As a result, the practical operating assessment results deviate from the design values. However, unlike the first kind of mismatched design, the practical assessment results cannot be enveloped by the design frontier, as shown in Fig 18A. Change rates of the ultimate Mxy-r and CPopt for each design point are also given in Fig 18B. As is shown, in comparison with the design value, the actual operating CPopt changes very slightly. However, in some cases, load of the practical operating assessment is significantly larger than the design value. The load is underestimated by about 4% in maximum. Fig 19 shows results of the second kind of mismatched design based on the ultimate Mxy-r and AEP. For the design ID<30, the Reynolds number effect is still rather little, the estimation error of Mxy-r is less than 2%, and AEP is underestimated by less than 0.5%. But for the design ID>35, AEP can be underestimated by up to 5.2%, while the ultimate Mxy-r can be underestimated by about 6.5% in maximum.


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

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

Results of the second kind of mismatched design based on the ultimate Mxy-r and CPopt.(A) Pareto frontiers of the mismatched design and the practical operating assessment, (B) excursion of the practical operating CPopt and Mxy-r from the mismatched design values
© Copyright Policy
Related In: Results  -  Collection

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

pone.0141848.g018: Results of the second kind of mismatched design based on the ultimate Mxy-r and CPopt.(A) Pareto frontiers of the mismatched design and the practical operating assessment, (B) excursion of the practical operating CPopt and Mxy-r from the mismatched design values
Mentions: To study the second kind of mismatched design, a wind turbine rotor practically running at Re = 6×106 is designed using the airfoil database at Re = 3×106. Fig 18 shows results of the second mismatched design based on the ultimate Mxy-r and CPopt. Similarly, on one hand, due to the Reynolds number effect on airfoil, the performance of the airfoils with the correct Reynolds number is better than the airfoil database used, while on the other hand, due to the mismatched airfoil database, the design deviates from the optimal shape. As a result, the practical operating assessment results deviate from the design values. However, unlike the first kind of mismatched design, the practical assessment results cannot be enveloped by the design frontier, as shown in Fig 18A. Change rates of the ultimate Mxy-r and CPopt for each design point are also given in Fig 18B. As is shown, in comparison with the design value, the actual operating CPopt changes very slightly. However, in some cases, load of the practical operating assessment is significantly larger than the design value. The load is underestimated by about 4% in maximum. Fig 19 shows results of the second kind of mismatched design based on the ultimate Mxy-r and AEP. For the design ID<30, the Reynolds number effect is still rather little, the estimation error of Mxy-r is less than 2%, and AEP is underestimated by less than 0.5%. But for the design ID>35, AEP can be underestimated by up to 5.2%, while the ultimate Mxy-r can be underestimated by about 6.5% in maximum.

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