A simple method to determine the frequency of engine-included thermoacoustic systems Original Research Article

Frequency determination is important for the simulation of a thermoacoustic system consisting of a thermoacoustic engine. Based on the characteristics of linear acoustics, this article proposes a simple method for frequency calculation through numeric investigation. According to the method, frequency value can be decided if it leads to an inflexion point of the amplitude of volume flow rate, which is also a local minimum, most close to the volume flow rate node boundary. Compared with experimental data, the method proves to be very reliable. Besides, a concept of virtual tube is also proposed for frequency determination of thermoacoustic systems with no apparent geometrically-closed end.