Abstract
Open-center ducted tidal turbines are a possible solution for tidal energy harnessing, particularly for low-velocity sea applications. These turbines are based on hubless rotor technology to reduce drag and a duct for flow acceleration and pressure stabilization. In this study, based on the computational fluid dynamics method, the effect of blade number and blade area ratio on the hydrodynamic performance are investigated systematically. Simulations were performed using Reynolds-averaged Navier–Stokes. The configurations were investigated under the same conditions with an inflow velocity of 1 m/s and a range of tip speed ratios from 1.0 to 2.5. Results indicate that maximum overall performance is produced by using the ten-blade reduced chord configuration with an average increase in power coefficient by 2.5% at all tip speed ratios compared to the baseline configuration. In contrast, the 10-blade fixed-chord design improved only at higher tip speed ratios. By decreasing blade area ratio, poor performance was observed with six-blade configurations, particularly at low tip speed ratios. These findings are fundamental for enhancing the efficiency of open-center ducted tidal turbines and optimizing efficient renewable energy devices under various operating conditions.