Abstract
To improve the performance of wind rotors by increasing an energy density of the wind, various power augmentation systems have been studied. The concentrator (nozzle) augmentation system is one of them. However, until now, the optimum design of concentrator is not revealed. The purpose of this study is to clarity the effect and to decide the optimum design of the concentrator. In conclusion, the effect of power augmentation was increased as following condition. 1. The position of the rotor is backward the outlet of concentrator. 2. The outlet diameter of the concentrator is smaller than the rotor diameter. 3. The inlet diameter is much larger than the rotor diameter.
