BEM Prediction of Wind Turbine Operation and Performance

Abstract

For continuous operation and production of energy from wind plants, blades, gearbox, shaft components undergo millions of revolution during the lift time and experience wear and tear due to unsteady aerodynamic forces. During this process the blades need to withstand forces which vary with prevailing wind speed and turbulence at site. In this work boundary element momentum method based numerical computations were performed for horizontal axis 2.1MW pitch controlled, upwind turbine of blade radius 37m. Reduction in blade relative velocity up to 3% is possible at 1800 azimuth position due to the tower effect was observed. A change of less than 1% in blade angle of attack was found for yaw and wind shear effects. The blade angle of attack has been validated using experiment and theoretical results from Gallant, Morote, and Elgammi study. Results showed better agreement near outboard section of blade than inboard region for above rated wind speeds. Data analysis was also conducted for variable speed active pitch regulated 2.1MW wind turbine of rotor diameter 95m and hub height of 80m at a site located in India. The results showed that maximum thrust and power coefficient was found to be 0.951 and 0.447 at wind speeds ~6 m/s and 9 m/s which agreed well with manufacturer’s data and computations.

Keywords: Wind turbine, Thrust, BEM, Torque, Power, Wind Speed, Angle of attack