A new thermoacoustic engine with its resonant frequency freely controlled by metallic-bellow unit

Thermally self-excited thermoacoustic engines are currently considered to drive regenerative refrigerators because of no moving parts in such a system. There are many factors that can affect the efficiency and miniaturization of the thermoacoustic systems. Among them, the operating frequency is most important one. To actively control the resonant frequency, we propose a new method. In our system, a unit made of a bellows attached by a metallic block is in introduced in the thermoacoustic system. Using different metallic bellows and blocks can easily control the operating frequency of the system. The design methodology is reported in the paper.