INFLUENCE OF TRAILING EDGE FLAPS ON HORIZONTAL AXIS WIND TURBINE PERFORMANCE

An experimental study has been carried out to investigate the performance of a horizontal axis
wind turbine model. The test has be done without and with flaps at trailing edge of turbine rotor,
one flap placed on pressure side of rotor blade and the other on its suction side. The turbine rotor
consists of three blades with tip diameter of 260 mm. The study covers the influence of different
blade angles with and without flaps on the wind turbine performance. Test data obtained *om
horizontal axis wind turbine rotor model tested in an open wind tunnel at different tip speed ratios
and different blade angles is used as a reference to make a comparison when rotor tested with
trailing edge flaps. The turbine torque and power are evaluated by the direct measurement of
rotational speed, and wind velocity. It was found that blade angle p of 45" is the better angle
giving maximum power coefficient of 22.6 % without flaps. Then turbine model is tested with
flaps on pressure and suction sides of its rotor blade at trailmg edge for p of 45'. Also, it is noticed
that flaps on pressure and suction sides of turbine rotor blade at trailing edge can improve wind
turbine performance. Also using flap of both pressure and suction sides increases power
coefficient of turbine model. The maximum improvement achieved was a 13.27 % increase in
power coefficient in case of model with pressure side flap for (L/CF = 0.75), and a 10.62 % in case
of model with suction side flap for (L/CF = 0.5). Flaps of pressure and suction sides achieved an
improvement of 19.47 % in turbine model power coefficient for pressure side flap with (L/CF =
0.75), and suction side flap with &/CF = 0.5).