Model Testing of a Series of Counter-Rotating Type Horizontal-Axis Tidal Turbines With 500 mm Diameter

Tidal current energy shows great attractive as it stores an enormous amount of predictable sustainable resource that can be extracted and used for the purpose of commercial power generation. The horizontal-axis tidal turbine (HATT) has been proposed as the most effective one among many tidal current energy extraction devices. It is well known that the similarities between horizontal-axis wind turbines (HAWTs) and tidal turbines suggest that much can be transferred from the design and operation of wind turbines. In the present work, a series of model counter-rotating type HATTs were designed according to the experience of a counter-rotating type HAWT, and a test rig was constructed. Experimental tests of the hydrodynamic performance in terms of power coefficient were carried out in a circulating water tunnel. Three model turbines consisting of different front and rear blades were analyzed. Experimental results of power coefficient for a range of tip speed ratios (TSRs) and setting angle matches between the front and rear blades for various conditions are presented. Such results provide valuable data for validating the hydrodynamic design and numerical simulations of counter-rotating type HATTs.