Influence of inner diameter and position of phase adjuster on the performance of the thermo-acoustic Stirling engine

A thermo-acoustic Stirling engine can convert thermal energy into useful acoustic power without moving parts, which can be used as driving power for the refrigerators and the generators. However, the low efficiency of the thermo-acoustic engine limits its commercial application. In this paper, to promote the performance of the thermo-acoustic engine, a phase adjuster (PA) is introduced by narrowing the cross-sectional area on the basis of the previous studies. The influences of the position and inner diameter of PA on the resonant frequency, pressure amplitude, acoustic power, sound direct current (DC) and efficiency are studied systematically. It is found that the maximal pressure amplitude, acoustic power and efficiency with optimal PA could be increased by 3%, 4.5% and 10% respectively compared to those without PA. In addition, the effect of PA on DC flow is also discussed in detail. Results show that the sound DC decreases with the farther position and smaller inner diameter of PA. Therefore, the suitable inner diameter and position can improve the efficiency of the engine, which needs to be weighed when designing or optimizing PA.