Researcher: Rodolfo Olvera-Trejo
Supervisiors: Dr Luke Myers
The aim of this project is to study the effect of adding winglets to a 1/20th scaled tidal turbine, and measure their impact on the Power and Thrust coefficients (CP and CT). In theory, an increase in the CP would be a result of the reduction of any tip losses. Previous CFD simulations and experiments carried out on wind turbines suggest that a winglet facing the suction side with a height of around 4% and a 25% radius would be optimal for this purpose.
A 1/20th scaled turbine with a torque-thrust dynamometer and an optical tachometer was fitted with 20 various winglet designs and tested in a towing tank.
The power and thrust coefficients (Cp and Ct) of the straight blades were plotted against the tip speed ratio (tsr) as a baseline.
A level of good agreement between experiments and the Blade Element Momentum (BEM) simulation was found while the winglets, which were analysed using an oil flow visualisation technique, were found to continuosly yield unexpected results.
Previous simulations and experiments on wind turbines, and simulations based on tidal turbines, suggested that placing winglets towards the suction side improved the Cpwithout compromising the Ct. It was found that facing them towards the suction side creates vortices .
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