An approach to low-temperature oscillation and high efficiency of thermoacoustic prime mover: influence of end face and reduction area of phase adjuster

The Phase Adjuster (PA) has contributed to the reduction of the onset temperature and improvement of the energy conversion efficiency of thermoacoustic systems. In this study, we investigated the performance characteristics of thin medal-shaped PAs representing the PA end faces. The results show that inserting 2 mm thick medal-shaped PAs lowered the onset temperature by 220 K. However, the insertion of thicker medal-shaped PAs maintained the onset temperature. In contrast, the energy conversion efficiency increased with the medal-shaped PA thickness. The energy conversion efficiency for 2 mm thick PAs was lower than that without PA. In addition, the thinner the medal-shaped PAs, the lower the power required for oscillation but the lower the energy conversion efficiency. These effects of the medal-shaped PA thickness indicate the necessity of different design guidelines for designing PAs for low-temperature oscillation and high efficiency in thermoacoustic systems.