Numerical simulation of flow dynamics in the periodic regime in an idealized thermoacoustic engine

L. Ma¹ - C. Weisman¹ - D. Baltean-Carlès¹ - I. Delbende¹ - L. Bauwens²

¹ Sorbonne Universités, UPMC Univ Paris 06, UFR919, 75005, Paris, LIMSI-CNRS, UPR 3251, rue John von Neumann, 91405 Orsay Cedex, France
² University of Calgary, Calgary Alberta T2N 1N4, Canada

Abstract
Flow dynamics in the stack and heat exchangers of a standing wave thermoacoustic engine is studied using two-dimensional direct numerical simulations. The numerical approach is based on asymptotic coupling in the low Mach number limit of a nonlinear dynamic model in the active cell with linear acoustics in the resonator. Computed results of the initial amplification and of the periodic regime eventually reached are shown. For the former, results show the existence of a critical temperature for which the system becomes unstable so that the engine starts, which is strongly dependent upon the load. Analysis of the results in the periodic regime shows the importance of vortex dynamics and the role of vortex shedding at sharp heat exchanger corners. Tables 1, Figs 4, Refs 7.