| With the deterioration of global energy crisis and environmental pollution, it hasbecome a general tend to develop and utilize new and renewable energies. Windenergy plays an important role in the development of new energies, with theadvantages such as accessible, on pollution, renewable，and so on. Wind power has apromising prospect and has been developed quickly in the world. Its development isalso significant to adjust energy structure, decrease environmental pollution, and solveenergy crisis.Blade is a critical component of wind turbine. Its airfoil and structure directlydecide the performance of wind turbine. Blade design is a complex multi-objectiveoptimization process. The well-designed blade not only has better aerodynamicperformance and higher energy conversion efficiency, but also can advance the wholeperformance of the wind turbine. Therefore, the thesis is founded by Jilin ProvinceDepartment of Science and Technology Development Plans "Study on the SystemDynamics Simulation for MW Wind Turbine (201205095)", to study a2MW windturbine’s aerodynamic structure and performance. The main research contents are asfollows1. The Blade Element Momentum theory is chosen to calculate wind turbineblade’s parameters. The designed parameters are optimized with Particle SwarmOptimization (PSO). The optimized blade gets a good starting performance. Chords’length and twist angles are more reasonable. And annual generation capacity isincreased by5.97%. Coordinates of each airfoil section are converted intothree-dimensional. Then the three-dimensional model of wind turbine blade is set up,which is laid foundation for aerodynamic analysis of the blade.2. Aerodynamic performance of airfoil has decisive influence on the overallperformance of wind turbine. The typical airfoil NACA4415, which is one of theairfoils chosen by the optimized blade, is numerically simulated. Through simulationof NACA4415, aerodynamic performance under the rated wind speed is obtained. Further more, factors affecting airfoil’s aerodynamic performance such as Reynoldsnumber, relative curvature and relative thickness are studied.3. ANSYS Fluent is used to numerically simulate the three-dimensional flowfield around blade，among which periodic boundary is set up. The contours of staticpressure of blade’s windward and leeward side and the air velocity and turbulentkinetic energy at section r/R=0.2、0.5、0.7are acquired. The cause for pressuredifference at blade’s windward and leeward is analyzed. By analyzing the results ofthe numerical simulation, the distributions of pressure, air velocity and turbulenceintensity along the blade are obtained. The results show that the air velocity andturbulent kinetic energy increase with r/R advancing. When air flow through the blade,there is no obvious separation and whirlpool, which mean there is a relatively stableflow. Turbulent kinetic energy around the airfoil increases from root to tip, and thatmay easily cause stall at the tip. The results show that the optimized blades have abetter aerodynamic characteristic.4. The aerodynamic and dynamics characteristics of whole wind turbine modelare studied. Firstly, the aerodynamic characteristics are calculated with CFX, and thecalculated results are loaded onto the solid turbine, then fluid-structure interaction iscompleted. Vibration frequencies，vibration types and magnitude of displacements aremainly analyzed. The interaction mechanism of blade deformation and loaddistribution are also studied. The static characteristic of wind turbine without stress isalso analyzed. The calculated results show that the design of the wind turbine is notlikely to occur resonance in the fluid-structure interaction. It comes to a conclusionthat the blade of wind turbine is well and reasonable desidned in this thesis. |
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