Theoretical study on a novel piezoelectric ocean wave energy harvester driven by oscillating water column

Abstract

ABSTRACT The wireless sensors offer the possibility of highly accurate salinity, temperature, or pollution detection for the ocean. Therefore, a novel self-powered piezoelectric wave energy harvester with a long service life was developed to replace the batteries in the sensors. A Pb(Zr,Ti)O3(PZT-5A) piezoelectric converter was applied to displace the traditional air turbine in this paper. The wave crest enters the chamber and compresses the entrapped air with oscillating water column (OWC). The outlet of piezoelectric patch deforms and output electric power when it is forced by the fluctuating air pressure. Based on the velocity potential and Green’s function method, theoretical analyses were conducted in the assumption of an incompressible fluid. A numerical OWC aerodynamic model was developed to verify the theoretical calculation based on the Reynolds-Averaged Navier-Stokes equations solver and Computational Fluid Dynamics (CFD) commercial software. The fluctuating air pressure was obtained in the chamber by numerical simulation. The pressure rose to 65 Pa when the ocean wave entered the air chamber with a daft of 0.3 m and a period of 1.8 s. Resultly, the piezoelectric harvester generates electric energy of J. This electric energy was used to evaluate the efficiency piezoelectric wave energy conversion system. Theoretical calculation results were consistent with that of the numerical simulation very well. This work testified their validity for the novel wave energy harvesting system.