Department of Mechanical Engineering

Mr. Songkai Wang

Degree Candidacy: Master of Science in Mechanical Engineering
Date: Wednesday, July 9, 2014
Time: 9:00 AM
Location: 215 EIB

Advisor: Dr. Gang Li
Committee Members: Dr. Mohammed Daqaq and Dr. Jane Zhao

Title: Theoretical and computational design analysis of a harmonica type aeroelastic energy harvester

ABSTRACT

A wind energy harvester inspired by music playing harmonicas was proposed for micro-power generation. The energy harvester utilizes flow-excited self-sustained oscillations of a piezoelectric cantilever beam mounted in a wind pipe to generate electric power. The dependence of the energy harvester's power generation performance on a set of the design parameters such as the chamber volume, aperture width and beam dimensions has been studied previously. However, the performance of the nonlinear multi-physics system with two-way fluid structure coupling also dependends on other design parameters such as the geometry of the oscillatory beam, the beam mounting configuration and the geometry of the pipe outlet. A systematic design analysis of the effects of these parameters is necessary for the optimization of the energy harvester.

In this study, theoretical and computational modeling and design analysis are performed to investigate the influence of the design parameters of beam geometry and pipe outlet structure on the performance of the wind energy harvester. It is known that the increase of the beam bending displacement induces a larger strain in the piezoelectric layer and a higher electric energy output of the wind harvester. In addition, the decrease of the threshold wind velocity and pressure will enhance the energy harvester's adaptability. The beam bending displacement and the threshold wind velocity are thus taken as the performance measures in this work. Theoretical models are developed to take into account different beam geometries. The analysis results show that the beam shape has a significant effect on the performance. 3-D finite element models are constructed for various designs. The theoratical analysis results are verified by the numerical simulations. In addition, by using the finite element model, the effect of several pipe outlet design parameters are studied. It is shown that the device performance can be improved with an optimal beam mounting position and a smooth pipe outlet wall.