Analysis of performances of a shrouded horizontal axis tidal turbine

Tidal current power generation is attracting more and more attention these days for its cleanness, predictability and reliability. A brimmed diffuser from Wind-lens technology is employed in this study. Experiments were carried out in the calculating water channel (CWC) for the bare turbine and the shrouded turbine, results of which proved that the diffuser was effective to improve the performance of the tidal turbine. The computational fluid dynamics (CFD) method and the blade element momentum (BEM) theory were used to evaluate the performance of the bare turbine and the shrouded turbine. For the tip speed ratio (TSR) around 3.0, calculation results from CFD and BEM fit experimental results well for the bare turbine. For the shrouded turbine, CFD results failed in capturing the experimental results but BEM results succeeded for the TSR greater than 3.0. In consideration of the actual running of turbines and calculation time cost, BEM is a satisfactory method for evaluating the performance of a turbine.