Caractérisation des écoulements redressés dans les moteurs thermoacoustiques à ondes progressives

Nonlinear phenomena in thermoacoustic devices are the cause of appearance of secondary flow called acoustic streaming and superimposed to the primary oscillating flow. The knowledge of control parameters as the second order time average pressure and velocity would lead to a better understanding of nonlinear phenomena responsible for a part of the system energetic efficiency decrease. In this paper, a method to investigate DC flow in thermoacoustic devices is developed and applied to an annular thermoacoustic prime-mover. The second order time average gradient and velocity is presented. A modelisation of the thermoacoustic engine is developed and the theoretical acoustic pressure is compared with experimental data. The relative error between theory and experiment is less then 10%. Mots clefs : acoustique non-lineaire ; thermoacoustique ; ecoulement redresse