Computational Analysis of a Wells Turbine for Wave Power Generation

Sea waves are an important renewable energy source, which, if appropriately exploited, can make a significant contribution to the electrical supply of areas surrounded by the sea.A number of technologies have already been proposed, studied and in some cases tested under real conditions.One of these technologies is the combination of an Oscillating Water Column (OWC) and a Wells turbine.The main purpose of this research is the design and analysis of a Wells turbine based OWC system and the development of an experimental facility in order to study this type of turbines under various simulated wave conditions.The paper presents the design procedure and the computational analysis of a Wells turbine for various air inlet flow velocities and rotor speeds.Flow field characteristics at steady and unsteady conditions are analysed using Computational Fluid Dynamics (CFD) and related to the rotor performance.The performance of the turbine was found to reach an efficiency of 60% at 4000 rpm before stall.The computational results are compared with corresponding test data from an experimental configuration which was built in order to investigate the turbine behaviour under oscillating inlet flow conditions.The computational and experimental results both demonstrate similar trends and their analysis facilitates the in depth understanding of the turbine operation.