LAUSR

Abstract Self-sustained oscillation in a standing wave thermoacoustic device is reproduced via computational fluid dynamics simulations, and heated flow behavior in the device is explored using the results obtained. The straight-type thermoacoustic device is composed of two resonance tubes, two heat exchangers and a stack. In these simulations, both the acoustic characteristics and the temperature field during self-sustained oscillation are considered. Therefore, to reproduce the self-sustained oscillatory flow, an acoustic signal is injected into the computational domain as a trigger pulse. From the results, oscillatory fluid motion around the engine is investigated, and characteristics, including the acoustic field or work flow, the energy dissipation, the work source and other associated aspects, are estimated. The results agree well with those of linear theory, although high energy dissipation caused by vortex generation is observed near the engine. This result verifies the computational fluid dynamics simulation results. The temperature field around the engine is also investigated. The results show occurrence of asymmetrical temperature oscillations within the heat exchangers. This behavior cannot be predicted using linear theory because the non-uniform temperature gradient in the engine unit is transferred in stream-wise by convection. Finally, a modification to conventional linear theory is suggested to reproduce this behavior.