Experimental investigation and performance modeling of centimeter-scale micro-wind turbine energy harvesters

Centimeter-scale micro wind turbines have been proposed to power small devices. Design models and operating conditions for large scale wind turbines do not directly apply towards these small harvesters. We perform an experimental investigation of a swirl-type micro-wind turbine. We measure the useful power extracted from this turbine in an open circuit suction type wind tunnel facility. The optimal resistive loads for different flow speeds are determined. A model for the friction, torque drive and generated power is derived and validated. The effect of varying the direction of incident flow on the turbine performance is also determined. The results show an optimal combination between the rotor diameter and the number of rotor revolutions. The power density and efficiency of this turbine were found to be larger than previously tested turbines that have slightly larger diameters. This is true over a broad range of free stream speeds. Finally, because of its shape, the swirl configuration is effective in harvesting power for yaw angles of ±30°.