Numerical Analysis of Wells Turbine for Wave Power Conversion

Article history: Received 26.04.2012. Received in revised form 17.07.2012. Accepted 17.07.2012. Sea wave energy is one of the high potential renewable energy sources. The Wells turbine as the main part of Oscillating Water Column energy plant is analyzed in this paper. The Wells turbine uses air flow produced by the pressure change inside the oscillating water column. Efficient energy transformation is achieved with the use of self-rectifying Wells air turbine. Since the tangential force of the rotor acts only in one direction, even though airflow is oscillating, turbine rotates always in the same direction. Series of numerical simulations are performed using software package FLUENT for a wide span of the non-dimensional flow rate coefficient and employing three different turbulent models. Structured numerical mesh and the application of axisymmetric periodical boundary conditions raised the accuracy of the numerical model while reducing computational load three times compared to the model with the fully meshed domain. Finally, the operation of the OWC plant consisting of the air chamber and the turbine was simulated for maritime conditions in the Adriatic sea giving satisfactory energy output by taking into consideration a compact dimension of the whole plant.