A Modeling Study Focused on Improving the Aerodynamic Performance of a Small Horizontal Axis Wind Turbine

Abstract

The excessive burning of the fossil fuels has excessively changed the global temperature in the last few decades. The global warming caused due to the burning of the fossil fuels has initiated a need of increasing the use of renewal energy sources. The wind energy is one of the renewable energy sources that can mitigate the excessive global dependency on the fossil fuels. For locations with low-to-medium wind speeds (less than 7 m/s), the main problem is with the starting of the wind turbine. To start a stationary wind turbine, not only is it necessary to overcome the inertia and static friction of the turbine, but the angle of incidence of the wind relative to blade profile also needs to be favorable. Thus, at low wind speeds, the resulting low torque is not enough to start the turbine. It is, therefore, necessary to incorporate a good starting torque in the design requirements of turbines. In this paper, a modeling study is performed using the Pro/E, ADAMS and MATLAB software to improve the starting behavior of a horizontal axis wind turbine for the Cherat location in the northern areas of Pakistan. The yearly average wind speed in the northern areas of Pakistan is less than 5 m/s. The blade element momentum (BEM) theory is used to calculate the optimized wind turbine blade parameters (blade angles and chord lengths) that correspond to the maximum starting torque. Based on the optimized wind turbine blade parameters, Pro/E models were developed and imported to ADAMS software to calculate the torque. As compared to the initial wind turbine model, for the optimized wind turbine model, the starting torque increased from 22.5 N-m to 28 N-m and the coefficient of performance (COP) increased from 0.42 to 0.49 at a tip–speed ratio of 4. The starting torque of the wind turbine should exceed the resistive torques due to bearing friction, generator static, dynamic torque and the inertia of the rotor in order to start the wind turbine. The starting behavior of the horizontal axis wind turbine was successfully improved, and the optimized wind turbine model showed an increased starting torque for low-to-medium wind speed ranges.