Experimental Investigation on a Fixed Oscillating Water Column with an Impulse Turbine for Wave Energy Conversion

A fixed oscillating water column (OWC)-type wave energy converter consists of an air chamber, an air turbine and a generator. The energy conversion processes are the primary conversion in an air chamber and the secondary conversion of the turbine. For the practical use, it is necessary to develop a design method which can consider the incident wave motion, the motion of the internal free surface affected in the structure such as a partly submerged wall, the fluctuation of air pressure in an air chamber, and the rotation of the air turbine. At here, the authors carried out the wave tank tests using the model OWC equipped with the impulse turbine and a generator to obtain the experimental data needed to make this design method. As the result, the efficiencies of the three cases with different speed ratio between generator and turbine, and the effects of the curtain wall depth and the wave length on the energy conversion performance were clarified.