Traveling Wave Thermoacoustic-Piezoelectric Energy Harvester: Theory and Experiment

Abstract

This thesis presents a theoretical and experimental investigation of a piezoelec- tric energy harvester coupled to a traveling wave thermoacoustic engine (TWTAE). By simplifying the engine using a lumped-parameter model, the performance pa- rameters such as pressure oscillation frequency and amplitude, regenerator hot end temperature, and piezoelectric output voltage are predicted. Also, an axisymmetric finite element model of the piezoelectric energy harvester is developed, resulting in a two-part reduced-order model of the electromechanical impedance of the harvester. The predictions of the finite element model are compared with those of ANSYS finite element analysis and validated experimentally. The two-part model is utilized in a numerical analysis of the TWTAE using DeltaEC (Design Environment for Low- Amplitude ThermoAcoustic Energy Conversion). Results from pressure transducers and the piezoelectric disc attached to a physical realization of the TWTAE are com- pared with theoretical predictions of the lumped-parameter models and DeltaEC analysis. The developed theoretical techniques and experimental validation provide invaluable tools for effective design of the thermoacoustic-piezoelectric harvester.