Multistage Wind Turbine Capability to The Rotor Axial Distance Changes

The multistage wind turbine is one of the Horizontal Axis Wind Turbine developments with the use of two rotors placed on one shaft. This type is developed to maximize energy conversion in a wind turbine by using residual energy from the first rotor. Experimental tests have been conducted to determine the multistage wind turbine capability at axial distance ratios of 0.10, 0.14, and 0.18 in some different wind speeds using wind tunnel. Multistage wind turbine showed a better performance than the single rotor wind turbine in the same tip speed ratio conditions. The maximum multistage wind turbine's performance achieved in a ratio of 0.18 on a tip speed ratio of 1.4 with the coefficient of power reaching 0.27. The placement of the two rotors affects the amount of wind speed decrease. The amount of wind speed that hits the second rotor determines the additional torque that can be generated in the second rotor to rotate. Different wind speeds will produce a different aerodynamic effect on the multistage wind turbine. The ratio of 0.18 has the largest torque increase up to 37% in the second rotor from the computational result. Increased torque causes an increase in the multistage wind turbine's performance.