Design and experimental evaluation of a travelling wave thermoacoustic engine

In a thermoacoustic engine, acoustic impedance plays a key role to improve the system performance. A matching stub is a component which can be applied to adjust the acoustic impedance. In this study, the effect of locations and lengths of the stub was investigated. The travelling wave engine was designed in looped-tube configuration operating at the frequency about 65 Hz. Air was applied as a working medium, operating at atmospheric pressure. The simulations and experiments were carried out to validate the function of the stub. With a variation of the stub length and its position along the looped-tube, the acoustic impedance can be fine-tuned to obtain the travelling wave phasing in the thermoacoustic core and maximum generated acoustic power.