Wave energy conversion: Design and shape optimization

Modified Wells turbines allow an efficient use of the power contained in the ocean and sea waves. The present study introduces the performance of an axial turbine which called Wells turbine. This turbine is used in oscillating water column (OWC) wave energy conversion devices. This type of axial turbine is investigated through numerical analysis and optimization. Unsteady 3D Reynolds-averaged Navier-Stokes equations were solved with k-ω SST turbulence closer model. A comparative study of optimized and conventional blades with steady and unsteady flows has been presented. For shape optimization, blade profile-thickness and sweep modifications along with and without grooved-casing, (GC) designs are considered. The results concluded that the reference blade with GC performs better in terms of torque coefficient and efficiency if the flow is attached. The unsteady flow gives a stream-wise circulation near the blade suction surface. The groove changes the tip vortex and helps to suppress the flow separation. In addition, the effect of blade sweep, profile variation and groove depth on the hysteresis behavior of the Wells turbine has been investigated in this work.