PIV measurement around vertical axis wind turbine with wing section which has cutout trailing edge

Abstract

The flow characteristics of a vertical axis wind turbine with the hybrid blade which has the wing section with cutout trailing edge for purpose to make advantages of the drag type and the lift type wind turbine have been investigated by measuring the velocity vector fields using the conditional sampling PIV. The experimental apparatus is constructed using the PIV measurement system with the conditional sampling device and a new hybrid vertical axis wind turbine model installed in a circulating water channel. Four experimental conditions as the tip velocity ratio 0.5, 1.0 1.5 and 2.0 are investigated. The flows around the turbine which influence the efficiency of the vertical axis wind turbine are defined by the measured velocity vector fields. Moreover, the alternations of the angle of attack and the relative flow speed ratio of the rotating blades in the measured velocity vector fields are calculated by analyzing the mean velocity vectors along the circumference of rotating blades. The influences of the flow over the torque generated on the blades are clarified as follows. The drag torque increases, and the advantage of the hybrid blade is effective under the conditions of the tip velocity ratio 0.5 to 1.0. And the lift torque decreases under the conditions of the tip velocity ratio 0.5, and the lift torque increases under the conditions of the tip velocity ratio 1.0.