| dc.description.abstract | Vertical Axis Wind Turbines (VAWT) play a key role in wind energy technologies,
where wind energy is one of the most cost-effective sources of renewable green
energy (Yokoi, 2005). VAWTs are not sensitive to the direction of the wind and do
not require any special mechanism to point out the turbine towards wind direction
like in Horizontal Axis Wind Turbines (HAWT). Different designs of VAWTs are
being used in the world and VAWTs excluding the Savonius type are taken into
consideration under this project scope, where its aerofoil blade profile is crucial for
efficiency. Generally, the VAWTs are less efficient relative to HAWTs. Also, the
VAWTs have a poor starting torque. Typical VAWTs utilise only the lift force acting
on the blades to make the turbine rotate. However, a limited number of hybrid blade
profiles are found to be invented for VAWTs, by which they can utilise both lift and
drag forces for the rotation of the turbine. In this study, a hybrid blade profile for
VAWTs is developed to make use of the combined effect of lift and drag forces with
the ultimate goal of achieving a higher efficiency in harnessing wind energy and to
overcome the problem of poor starting torque. CFD simulations were performed to
evaluate performance of existing hybrid blade profiles, and the best design out of
those profiles was further modified and evaluated to meet the objectives. Prototype
of the modified blade profile was fabricated and tested with a comprehensive testing
equipment developed and fabricated to evaluate the practical performance of the
blade profiles. | en_US |
