Investigations on modified vertical axis wind turbine blades

Abstract

A windmill uses the energy form the wind to produce mechanical energy. Commonly the windmills are classified into two types based on their axis of rotation as horizontal and vertical axis wind turbines. A vertical axis wind turbine has its main rotor shaft set in transverse to the wind and the other components are fitted at the base of the turbine. This makes repairing and over hauling works easier. Vertical axis windmills does not requires a long tower structures and can be constructed at lower costs and also can be fitted at the house roof tops. In this work the blade design of the vertical axis wind turbines are modified to trap more energy from the available wind and to produce more output. For this the blades were designed in three types such as flat blade, conical and conical with air trappers. Thus the wind mill is tested by fitting the three types of blades one by one and compared for maximum efficiency. Also the number of blades also changed in the order of 2, 3 and 4 blades. Three parameters were found to be the most influencing parameters and the parameters are changed and tested to find out the optimum design. The number of blades, blade design and material of the blade were chosen are the three parameters. Finally it was found that the design with four blades, conical blade with air trappers and fitted with aluminium sheet gives the most efficiency.