Dynamic behavior modeling and energy conversion characteristic analysis of a thermoacoustic-piezoelectric generator with the consideration of thermal and viscous losses

Abstract

The amalgamation of thermoacoustic and piezoelectric principles represents a promising approach to bolster energy harvesting capabilities, offering a viable solution to address the increasingly pressing environmental concerns and energy shortages. This research introduces a thermoacoustic piezoelectric generator, serving as a versatile platform for the efficient interplay of thermal, acoustical, mechanical, and electrical energies. The proposed system comprises distinct components, including a hot buffer, stack, resonators, and piezoelectric transducer. At the left end of the system, a generalized impedance boundary condition is employed. Theoretical models, rooted in the wave equation and thermoacoustic theory, are meticulously developed. These models leverage the smoothed-Fourier series and the Galerkin method, presenting a generalized eigenvalue problem encompassing oscillation frequency and the corresponding coefficients of acoustic pressure. These models are rigorously validated through comparisons with existing literature. Building upon the established model, this study thoroughly investigates the influence of various geometrical and electrical parameters, such as tube length, stack position, external load, and the impact of the general impedance boundary condition, on dynamic behaviors. These dynamic behaviors encompass the onset frequency, and the distributions of acoustic pressure, volume velocity, acoustic impedance, as well as energy conversion characteristics, including captured energy and energy capture efficiency. The theoretical model and analytical framework developed in this study hold significant utility in the design and optimization of thermoacoustic piezoelectric generators. They are poised to advance the field of energy harvesting technology, fostering substantial growth across a multitude of industrial applications.