Effect of tip speed ratio of rear stage impeller on the performance of contra-rotating wind turbine

Based on the experimental research and numerical calculation of the Contra-Rotating Wind Turbine (CRWT) by using the technique of the aero-engine and propeller, the effect of the tip speed ratio of the rear stage on the performance of the contra-rotating wind turbine is studied by using numerical simulation method in this paper. The computational results show that there is an optimal tip speed ratio on the rear stage of the contra-rotating wind turbine under medium wind speed in order to achieve the highest output power. Below the optimal value, boundary layer separation of the rotor blade is serious, output power is lower, and output torque is larger; above the optimal value, the opposite situation occurs. Through analyzing the computational results, the optimal value of tip speed ratio of rear stage impeller is 1.667.