Efficiency enhancement of a unidirectional impulse turbine for dual-chamber OWC wave energy converters

Abstract

To address the efficiency limitations of conventional bidirectional turbines in oscillating water column (OWC) wave energy conversion systems, this study proposes a novel dual-chamber OWC configuration coupled with unidirectional impulse turbines. A steady-state Computational Fluid Dynamics (CFD) model based on viscous fluid theory was established and validated against experimental data. Using this model, a comprehensive parametric optimization was performed on rotor blade number, guide vane number, and blade installation angles to enhance aerodynamic performance. The optimized unidirectional turbine achieved a 59.89 % increase in average efficiency and a 67.97 % improvement in peak efficiency compared to a reference bidirectional turbine. Furthermore, the total number of rotor blades and guide vanes was reduced by 26.67 % and 42.31 %, respectively, significantly lowering material requirements and manufacturing costs. Flow field analyses revealed improved pressure distribution, reduced separation zones, and enhanced wake uniformity. This study demonstrates the potential of integrating unidirectional turbines into dual-chamber OWC systems to improve energy conversion performance and reduce structural complexity. The findings provide valuable design insights for wave energy converters. Future work will extend to transient simulations and experimental validation under oscillatory flow conditions.