A novel non-linear one-dimensional unsteady model for thermoacoustic engine and its application on a looped traveling-wave thermoacoustic engine

Abstract

A novel non-linear one-dimensional unsteady model (1DUM) for thermoacoustic engine is proposed to study on the working mechanism of thermoacoustic engines, with its focus on the unsteady onset process. Numerical simulation of a looped 3-stage traveling-wave thermoacoustic engine (TWTAE) is carried out based on this model. The complete self-excited onset process from static state to saturation is firstly realized in simulation without introducing any external disturbance. The simulation results indicate that the thermal conduction is a crucial factor to excite the oscillation in transient onset process. The onset mechanism and energy balance of thermoacoustic engine is then explained. Experimental work and calculation based on the linear thermoacoustic simulation platform, DeltaEC, are carried out to verify the model. It is shown that the calculated frequency and the proportion of the high-order harmonics by 1DUM agree well with the experiment, and 1DUM presents a reliable acoustic field distribution for the looped multi-stage TWTAE without empirical inputs like DeltaEC, which greatly simplifies the modeling process. Compared with computational fluid dynamics (CFD), 1DUM is more efficient at simulating the non-linear and unsteady onset process.