Design and Fabrication and Testing of a Low Speed Wind Turbine Generator Using Tapered Type Rotor Blade Made from Fibre Reinforced Plastic

Abstract

This study fabricated a three bladed wind turbine of 0.6 m rotor diameter. The blade was divided into ten sections and shape derived from the blade element and momentum theory with two linearization points at 70% and 90%.. Other design values chosen were; clark Y as the airfoil type, 2.5 as tip speed ratio, 1.1 as lift drag ratio, design angle of attack of 8o. The rotor blades were fabricated using two layers of fibre reinforced plastic and 2% hardenning on resin. The power coefficient of the turbine was tested in the wind tunnel by subjecting it to wind speeds ranging from 4 m/s to 10 m/s in the wind tunnel testing. The wind tunnel used for the study was the Effel type with an exit of 1.05 mX1.05 m and wind speed adjustable between 2 m/s to 22.5 m/s. An induction motor was used to provide the load in the experiment and the synchronized frequency controlled by an inverter. A direct connection generator was employed to the turbine rotors to determine the electricity generation capacity. The maximum coefficient of power for the blade was found to be 0.26 at 10 m/s and 651 rpm. A variable resistance was used to determine the electric power production at different rotational speed. A speed of 10 m/s gave the highest power of 29.69 W at 891 rpm, 8 m/s gave the highest power as 15.43 W at 688 rpm, 6 m/s gave the highest power as 6.38 W at 552 rpm while 4 m/s gave the highest power as 1.74 W at 302 rpm. The Wind generator was then used to charge a 54 AH, 12 V battery producing the highest electrical power of 32.03 W. The turbine is capapble of producing power for small wind regimes with small household usage however it is recommended that the design should be optimized to improve the coefficient of power.