Abstract
Darrieus turbine with straight blades has an advantage over a horizontal-axis turbine in the simplicity and in independency to a current direction. In order to improve the selfstarting performance of Darrieus turbine, the pitch angles of the blades are varied and tested in a low-speed wind tunnel. First, the pitch angles of the blades are varied coarsely to evaluate the possibility of the improvement. The generated torque on the turbine is measured by the torque meter in a tip-speed ratio from 03 to 1.2. Then, based on the obtained results, the pitch angles of the blades are again varied but in a range from -15 to 15 degrees. As a result, it is found out that the pitch angle of -10 degrees gives the largest torque below 0.8 in a tip-speed ratio. Once the turbine reaches 1 in a tip-speed ratio, then the blades with a pitch angle of 4 and 6 degrees are advantageous to accelerate the turbine.