TY - JFULL AU - M. Raciti Castelli and S. De Betta and E. Benini PY - 2012/4/ TI - Numerical Analysis of the Performance of a Shrouded Vertical-Axis Water Turbine based on the NACA 0025 Blade Profile T2 - International Journal of Aerospace and Mechanical Engineering SP - 697 EP - 705 VL - 6 SN - 1307-6892 UR - https://publications.waset.org/pdf/716 PU - World Academy of Science, Engineering and Technology NX - Open Science Index 63, 2012 N2 - This paper presents a numerical analysis of the performance of a five-bladed Darrieus vertical-axis water turbine, based on the NACA 0025 blade profile, for both bare and shrouded configurations. A complete campaign of 2-D simulations, performed for several values of tip speed ratio and based on RANS unsteady calculations, has been performed to obtain the rotor torque and power curves. Also the effect of a NACA-shaped central hydrofoil has been investigated, with the aim of evaluating the impact of a solid blockage on the performance of the shrouded rotor configuration. The beneficial effect of the shroud on rotor overall performances has clearly been evidenced, while the adoption of the central hydrofoil has proved to be detrimental, being the resulting flow slow down (due to the presence of the obstacle) much higher with respect to the flow acceleration (due to the solid blockage effect). ER -