A Study on Performance of New Tidal Energy Converter for Tidal Current Extraction Using Computational Fluid Dynamics

摘要

Renewal energy technologies are increasingly popular to ensure future energy sustainability and to balance environmental issues. The growing interest in exploring tidal energy has compelling reasons such as security and diversity of supply, intermittent but predictable and limited social and environmental impacts. The energy available in tidal currents or other artificial water channels is being considered as viable source of renewable power. Hydrokinetic conversion systems, albeit mostly at its early stage of development, may appear suitable in harnessing energy from such renewable resources. A concept of tidal energy converter (TEC) which is based on shape of the conventional water wheels, is introduced in this study. Basically, this turbine has several special features that are potentially more advantageous than the conventional tidal turbines, such as propeller type tidal turbines. The research aims to study the possibility of twelve-blade turbine in extracting the hydrokinetic energy of tidal current and converting it into electricity, and evaluate the performance of the turbine at different given arrangements of blades (single and double rows) using Computational Fluid Dynamics (CFD). In all cases of tip-speed ratio (TSR), the twelve-blade double-row type obtains higher power efficiency, especially about 20% power coefficient at TSR = 0.75, in comparison with 13% power coefficient of the single-row one. Furthermore, by changing the arrangement of rotating blades, the torque's absorption from the rotor shaft of twelve-blade double-row turbine is more uniform due to the less interrupted and fluctuated generation of force for a period of time (one revolution of the rotor).