INFLUENCE OF IMPEDANCE-TUNING ON THE THERMO-TO-ACOUSTIC CONVERSION FOR A LOW-COST CASCADE THERMOACOUSTIC ENGINE

This paper presents the effect of acoustic impedance adjustment by modifying the configuration and geometrical dimensions of system on the energy conversion efficiency in a low-cost cascade thermoacoustic engine. This device consisting of one standing-wave unit and one travelling-wave unit in series is designed to meet the energy requirements of remote and rural communities. Since the acoustic impedance in regenerator could be considered as the proportion between the acoustic power generated by thermoacoustic effect and the acoustic power dissipated by viscous and thermal-relaxation effects, high impedance is needed for the powerful system. Based on the analysis provided, a various techniques of impedance-tuning are investigated numerically and experimentally to adjust the position of the sweet spot and phase in the regenerator.