Slosh-induced piezoelectric energy harvesting in a liquid tank

Abstract

When a tank containing a liquid is excited externally, the free surface of the liquid becomes violently distorted, generating a large amount of wave energy. We suggest a novel model for harvesting wave energy produced by such sloshing. A deformable energy harvester with an attached piezoelectric patch is mounted vertically in the middle of a liquid tank. By varying the excitation amplitude and frequency of the tank, the level of water, and the thickness of the harvester, the dynamics of the harvester are investigated in terms of tip deflection and phase difference. The excitation frequency corresponding to sloshing resonance is critical for producing large tip deflections. Near resonance, the motions of the tank and the harvester are not necessarily synchronized, and there are large variations in the phase difference. The performance of the energy harvester is evaluated by measuring the open-circuit voltage, short-circuit current, and output power with an electrical load. The model has exceptional power generation performance and would be suitable for supplying power to small electrical devices. Moreover, the harvester is effective in suppressing the peak hydrodynamic pressure exerted on the tank wall, which suggests dual functions of our model as an energy harvester and as a baffle.