Design Optimization of a Multi-Megawatt Wind Turbine Blade with the NPU-MWA Airfoil Family

Abstract

A new airfoil family, called NPU-MWA (Northwestern Polytechnical University Multi-megawatt Wind-turbine A-series) airfoils, was designed to improve both aerodynamic and structural performance, with the outboard airfoils being designed at high design lift coefficient and high Reynolds number, and the inboard airfoils being designed as flat-back airfoils. This article aims to design a multi-megawatt wind turbine blade in order to demonstrate the advantages of the NPU-MWA airfoils in improving wind energy capturing and structural weight reduction. The distributions of chord length and twist angle for a 5 MW wind turbine blade are optimized by a Kriging surrogate model-based optimizer, with aerodynamic performance being evaluated by blade element-momentum theory. The Reynolds-averaged Navier-Stokes equations solver was used to validate the improvement in aerodynamic performance. Results show that compared with an existing NREL (National Renewable Energy Laboratory) 5 MW blade, the maximum power coefficient of the optimized NPU 5 MW blade is larger, and the chord lengths at all span-wise sections are dramatically smaller, resulting in a significant structural weight reduction (9%). It is shown that the NPU-MWA airfoils feature excellent aerodynamic and structural performance for the design of multi-megawatt wind turbine blades.Energies 2019, 12, 3330 2 of 24 designed by National Aeronautical Research Institute of Sweden [10]. The Northwestern Polytechnical University (NPU) of China has developed a family of NPU-WA (Northwestern Polytechnical University Wind-turbine A-series) airfoils for megawatt wind turbines, featuring a high lift-to-drag ratio at a high Reynolds number and a high lift coefficient [11][12][13][14]. The Chinese Academy of Sciences (CAS) has designed a family of CAS airfoils for medium Reynolds numbers [15]. The Chongqing University of China and Technical University of Denmark have developed the CQU-DTU-series airfoils, taking into account of the aerodynamic performance and low noise requirements [16]. Compared with the conventional aeronautic airfoils, the dedicated airfoils for wind turbine blades have a higher lift-to-drag ratio, which means that the aerodynamic force of the blades has a larger component in the tangential direction of the wind wheel and lower component in the axial direction (thrust), resulting in smaller thrust with the same tangential component of aerodynamic force, thus the total aerodynamic load is reduced.With the continuous development of wind turbine technology, the wind turbine generator system tends to become larger and larger. The blade diameter of wind turbines has increased from about 20 m in the 1980s to nearly 200 m, or even more now. Meanwhile, the capacity has also been increased, from 20 kW~60 kW to 5 MW~10 MW [17][18][19]. In recent years, the technology for applying the wind turbine-dedicated airfoil family to megawatt wind turbines (1.0 MW, 3.0 MW) has gradually matured. More and more attention has been paid to the development of new airfoil families dedicated t...

RETRACTED: Techno-economic analysis and modelling of the feasibility of wind energy in Kuwait

“…It means that at most, only 59.3% of the kinetic energy from wind can be utilized to spin the turbine and generate electricity. The difference in efficiency is due primarily to the nature of wind turbines, not the inefficiency of the generator [14][15][16][17]. To achieve 100% efficiency, wind turbines should convert 100% of the wind; however, doing so would necessitate solid disc blades, which would prevent the rotor from turning because of their great weight, and no kinetic energy would be converted [18].…”

Aerodynamic design of wind turbine blade with second derivative of thickness distribution as constraint

“…Some well-known software for wind turbine blade design and analysis, such as GH Bladed [10] and PRPPID [11] , are based on this method. An in-house Reynolds-Averaged Navier-Stokes solver for blade, called ROTNS [12] , is used to validate aerodynamic performance of the optimized blade.…”

Techno-Economic Analysis and Modelling of the Feasibility of Wind Energy in Kuwait

“…It describes the efficiency with which kinetic energy is converted into mechanical energy. The difference in efficiency is due primarily to the nature of wind turbines, not the inefficiency of the generator [15][16][17][18]. To achieve 100% efficiency, wind turbines should convert 100% of the wind; however, doing so would necessitate solid disc blades, which would prevent the rotor from turning because of their great weight, and no kinetic energy would be converted.…”