Abstract
In order to improve the performance of wind rotors by increasing the energy density of the wind, various power augmentation systems have been studied. One of them is the concentrator (nozzle) augmentation system. However, until now, the optimum design of the concentrator has not been clarified. The purpose of this paper is to study the effect of the various concentrators and to decide its optimum design. In conclusion, the effect of power augmentation is increased in following conditions:
1. When the position of the rotor is behind the outlet of the concentrator.
2. When the outlet diameter of the concentrator is smaller than the rotor diameter.
3. When the inlet diameter is much larger than the rotor diameter.
