Feasibility Study of a Hybrid Solid Liquid Vibration Energy Harvester: Numerical Simulation & Analysis

Abstract

In this paper, we have introduced and studied the feasibility of a hybrid solid liquid vibration energy harvester. The energy harvester consists of a ferrofluid partially filled in a tank and a piezoelectric beam fixed at one of the tank walls. The tank is assumed to be placed in a nonuniform magnetic field created by placing two powerful magnets symmetrically external to the tank walls. This magnetic field was then implemented by a Magnetic field function modeling the magnetic field produced by the two magnets. We used piezoelectric beam configurations and oscillation loads to study and characterize this 2D multiscale, multiphysics, and multiphase fluid structure interaction. The tank is subjected to an external oscillatory motion, which sloshes the ferrofluid and oscillates the beam utilizing two modes, one due to the beams inertia and the second due to the impact of the ferrofluid on the beam. The parameters varied in piezo materials, ferrofluid fill height, piezoelectric beam length, and oscillation frequency. The natural frequency modes for the piezoelectric beam are very important since the beam harvests the highest power in those modes. We have observed that when the fluid motion vibrates the beam, in some instances, the voltage output from piezoelectric material peaks to a high value, which is indicative of material nearing resonance frequencies at the fluid loading realized in those instances. However, in other cases, the voltage output varies with the loading, and hence, the response of the piezoelectric beam is broadband, very similar to the sloshing, which is inherently broadband.