CFD-Based Optimization of an Axial Impulse Turbine for a Twin-Turbine Topology of an OWC Wave Energy Converter

Oscillating water column (OWC) devices have been among the most extensively studied wave energy converters over the past decade. This paper focuses on a specific OWC configuration that employs twin unidirectional axial turbines, which alternate their operation to generate energy based on the oscillating motion of the water’s free surface. Despite numerous studies, these turbines have never undergone a comprehensive optimization process. This study presents an optimization process applied to a previously documented turbine geometry to determine an optimal design based on a five-parameter selection. The optimization was conducted using a genetic aggregation method aimed at maximizing efficiency in direct flow mode. A computational fluid dynamics (CFD) model, validated against experimental data, was used to construct the response surface for the optimization. The results demonstrated a 28% increase in efficiency at low flow coefficients compared to the original design. The optimized geometry significantly reduced energy losses, with reductions of approximately 66.2% and 22.3% at flow coefficients of Ø = 0.25 and Ø = 0.50, respectively. Furthermore, an unsteady performance evaluation revealed a 12% increase in the turbine’s peak efficiency and a 2% improvement in blocking efficiency compared to the initial design.