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 and would be applicable within area with low wind regimes providing power for small household usage. However it is recommended that the design should be optimized to improve the coefficient of power.

Key  words: Coefficient  of  power, tip  speed  ratio,  angle  of  attack,  wind  tunnel,  wind speed,  tapered  type, rotor blade