Improving the Value of the Power Coefficient for Three Straight-Blades Darrieus Wind Turbine

In this study, an experimental test was carried out using a subsonic wind tunnel to study the improvement of the power coefficient of the three straight-blade Darrieus vertical axis wind turbine. A three-blade vane type vertical axis wind turbine with three movable vanes in each of the blades was fitted in the middle of the three straight-blade Darrieus (0012 Airfoil) vertical axis wind turbine, and they are installed on the same rotor shaft. For this purpose, two vertical axis wind turbine, the first one has three straight-blades Darrieus of type 0012 Airfoil and the second also has three straight-blade Darrieus but of type 0012 Airfoil with a three-blade vane type vertical axis wind turbine with three movable vanes were manufactured. Both turbines were tested using a subsonic wind tunnel at different wind speeds ranging from (4-28) m/s. The consequences showed that in the second turbine test, a power coefficient of C_p=0.39 was obtained, which is greater than the power coefficient of the first turbine (C_p =0.184) after the turbines were tested in a wind tunnel under identical conditions at a wind speed of 6 m/s. Therefore, the second wind turbine produces greater electrical power than the first wind turbine.