An integrated numerical model for the chamber-turbine system of an oscillating water column wave energy converter

Abstract

Oscillating Water Column (OWC) has been the most successful technology in the coastal application of wave energy conversion. In the primary energy-conversion stage, the air chamber converts the wave power to the pneumatic power. Subsequently, the self-rectifying turbine converts the pneumatic power into the electricity in the secondary stage. In traditional studies, these two energy conversion stages were studied separately with some simplifying assumptions or damping substitutions. In this study, an integrated numerical model was established firstly to recruit both the air chamber and the self-rectifying turbine and associate multiple energy-conversion stages together. This integrated model was comprehensively verified and validated by experimental waveflume tests for two operating modes of an impulse turbine under regular and irregular wave conditions. The air compressibility in the model was also validated by previous results. The flow fields, vortex structures, and the pressure distributions of the chamber-turbine system for a typical validating case were illustrated to reveal the physical phenomenon and mechanism in the complicated interactions between two energy-conversion stages. The reasonably good agreements of the operating parameters between the numerical predictions and experimental results demonstrated a great potential of the integrated model in the application of numerical studies on the full-scale OWC prototype in the future.