Experimental study on hydrodynamic behavior and energy conversion of multiple oscillating-water-column chamber in regular waves

Abstract

An oscillating water column (OWC) device is a promising wave energy converter that uses ocean wave energy resources. The OWC chamber absorbs the energy of ocean waves and significantly affects energy conversion performance. In this study, the hydrodynamic performance of a multiple OWC chamber was investigated experimentally, emphasizing its hydrodynamic behavior and energy conversion characteristics. A series of regular wave tests were conducted for single-, triple-, and asymmetric triple OWC chambers in a two-dimensional wave tank. The same orifice ratio was applied to the single and triple chambers to induce an equivalent turbine-chamber interaction owing to the pressure drop. It was found that the triple OWC chamber contributes to an increase in the converted pneumatic power compared to the single OWC chamber due to reducing the sloshing motion of the internal fluid. Moreover, the temporal fluctuation of the overall output power was reduced because of the water column motion of each triple OWC chamber with a phase difference. The rear chamber of the asymmetric triple chamber traps the wave energy and contributes to not only increasing the output power but also the variability. Therefore, it can be observed that multiple OWC chambers improve energy conversion performance by increasing the mean power output and reducing temporal fluctuation.