Nonlinear modeling of thermoacoustic systems

Thermoacoustic systems convert energy from heat to acoustic power and vice versa. These systems have commercial interest due to the high potential efficiency and low number of moving parts. To numerically predict the performance of a thermoacoustic device inherent nonlinearities in the system, such as thermoacoustic streaming and generation of harmonics need to be taken into account. We present a nonlinear frequency domain method with which these nonlinearities in thermoacoustic systems are modeled in a computationally efficient manner. Using this method, the nonlinear periodic steady state of a thermoacoustic engine can directly be computed, without computing the long initial transient of the system. In this publication, the developed method is applied to compute the periodic steady state of an experimental standing wave engine. The results obtained match well with experimental data. PACS no. 43.35.Ud,43.25.Ts,43.25.Gf