AIRFOIL-BASED SELF-ADJUSTABLE PIEZOELECTRIC ENERGY HARVESTER IN FLUID-FLOW APPLICATIONS FOR PERFORMANCE OPTIMIZATION

Abstract

Piezoelectric vibration energy harvesters can be utilized to harvest kinetic energy from fluid flow for remote sensing applications. Vortex formation behind a bluff body that is coupled to a beam oscillates with two frequencies in transverse and inline directions. A macro-fiber composite converts the mechanical strain in the beam to electricity that can power sensors for wireless monitoring and automation. Since the flow is random and broadband, the main challenge with the narrow frequency bandwidth of linear energy harvesting is the conversion efficiency. A passive airfoil beam design is proposed to self-align with the changing direction of flow. Computational simulations demonstrate the airfoil geometry has an optimal placement for piezoelectric patches. Additionally, its peak performance output is increased by 290% compared to a conventional beam of the same volume in modal analysis. This means that energy harvesting performance can be shown to be feasible for open-channel applications such as rivers. Also, the synchronization frequency spectrum highlights that low-velocity application is possible and presents a better alternative to turbines that suffer from electromechanical losses with miniaturization.