Research On Vertical Axis Variable Blade Pitch Turbine Design To Extract Power From Tidal Current

Tidal energy has advantages in being predictable and reliable .Research for accumulation of knowledge related to tidal current resources, the physical process involved in tidal current energy extraction and its consequence, are essential for the successful exploitation of this natural resource. A number of methods have been introduced in the field, Turbines prove to be the one of most efficient source to workout for the said purpose.In this paper studies based on research caries out to use vertical axis turbine for the tidal current extraction, the focus is to develop the vertical axis turbine with a simplified variable pitch mechanism. This configuration allows the rotor to always rotate in the same direction and be insensitive to tidal current direction. A conventional fixed pitch vertical axis turbine cannot usually start rotating on its own and only is able to work efficiently at very high tip speed ratios. As a result, a self-start motor will be required. Variable pitch vertical axis turbines have been proposed, which can markedly increase the power extraction efficiency at low tip speed through controlling the rotor blades pitch at all points of their rotation cycle. Tidal turbine model has been developed with two different variable blade pitch control mechanisms, (a) planar multi-bar variable-pitch structure to control the working performance of variable blade pitch, (b) cam controlled variable blade pitch mechanism. Kinematic analysis carries out to evaluate the functionality of mechanisms and its degree of freedom. Stress analysis on main frame parts has been performed to evaluate the efficiency of structure in variable environmental conditions.Virtual prototype model for both mechanisms has been developed in Pro/E software, to validate the behavior of design. Modal analysis has been performed to obtain the natural frequency and deformation shape of turbine blade. For the said purpose, Turbine blade geometry has been meshed in Altair Hypermesh environment and modal analysis performed up to five frequency levels in Ansys software. To validate the effectiveness of cam design, velocity and acceleration curves have been obtained in Msc Adams software environment.