الفهرس 
CHAPTER 1 INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The field of wind energy has made significant progress, yet there is always room for improving efficiency and the energy extracted from horizontal axis wind turbines HAWTs. This study aims to investigate the effect of adding flaps, to the turbine blades, on the performance of a HAWT at different numbers of blades, different blade angles, and flap angles and position. Therefore, an experimental setup includes a model of wind turbine was constructed. The performance of the model is examined, in this research, via wind tunnel tests. The model is initially tested without flaps at various blade angles of 10o, 15o and 20o; with two, three, and six-bladed rotors. After that, it is tested with adding flaps at the leading and trailing edges of the model. For the leading-edge flaps experiments, the flaps was positioned first towards the pressure surface of the blade with flap angle of 30o, 40o and 50o. Then, it was positioned towards the suction side surface at angle of 10o, 20o and 30o in the opposite direction. Finally, the flaps were implemented at the trailing edge at angle of 40o, 50o and 60o. The results show that, for model without flaps, the best blade angle is 15o that gives the best performance for two-, three-, and six-blades. Also, the use of trailing edge flaps gives the best performance. An improvement of 55.6 % in the maximum power coefficient, is achieved when three-bladed rotor was utilized, compared with that of the reference case (without any flaps). Moreover, the flap angle of 50o is the best angle for the trailing edge flap in the current investigation. In the other hand, adding flaps at the leading-edge near the pressure side, gives the worst performance even less than the reference case. However, adding flaps at the leading-edge near the suction side, gives a slight improvement in the performance of about 10% compared to the reference case, and the best flap angle was 10o.