Acoustic characteristics and performance analysis of a solid-state thermoacoustic oscillator

Thermoacoustic instability in solids paves the way for the development of solid-state thermoacoustic (SSTA) engines with superior reliability. Acoustic characteristics with respect to the performance of SSTA oscillators are investigated, where growth ratio is taken as a performance metric. Numerical analyses show that the acoustic characteristics not only determine the temperature gradient direction for strengthening the oscillation, but also affect the maximum growth ratio. A high growth ratio is obtained at a low angular frequency and an acoustic field around 1/8 wavelength from the strain antinode. To realize appropriate acoustic characteristics, the angular frequencies and acoustic fields under different boundary conditions are studied, based on which the method to adjust the acoustic characteristics is discussed. This work aims to reveal the relationship between the acoustic characteristics and the performance of SSTA oscillators, and to provide new insights on adjusting the acoustic characteristics for improving SSTA oscillators.