A simplified model for linear and nonlinear processes in thermoacoustic prime movers. Part II. Nonlinear oscillations

Abstract

The simplified quasi-one-dimensional model of thermoacoustic devices formulated in Part I [Watanabe et al., J. Acoust. Soc. Am. 102, 3484–3496 (1997)] is studied in the nonlinear regime. A suitable numerical method is described which is able to deal with the steep waveforms that develop in the system without inducing spurious oscillations, appreciable numerical damping, or numerical diffusion. The results are compared with some experimental ones available in the literature. Several of the observed phenomena are reproduced by the model. Quantitative agreement is also reasonable when allowance is made for likely temperature nonuniformities across the heat exchangers.

Thermoacoustic simulation with lattice gas automata

“…The asymmetry of the pressure wave profiles relative to the average pressure level is also due to the nonlinearity resulting from high amplitude thermoacoustics. 8 The onset feature of thermoacoustic oscillation shown in Fig. 2 was also demonstrated in early publications 8,9 by measurements or calculations.…”

“…8 The onset feature of thermoacoustic oscillation shown in Fig. 2 was also demonstrated in early publications 8,9 by measurements or calculations.…”

Numerical investigations of flow and energy fields near a thermoacoustic couple

“…Several works have addressed the numerical simulation of thermoacoustic devices, but most have concentrated on the regenerators ͓Worlikar and Knio ͑1996͒; Watanabe et al ͑1997͒;Yuan et al ͑1997͔͒. In addition, although nonlinearity is incorporated into their models, various simplifications to the governing equations have been made.…”

Weakly Nonlinear Propagation in Thermoacoustic Engines: A Numerical Study of Higher Harmonics Generation up to the Appearance of Shock Waves

“…The saturation of the growth of amplitude is then controlled by nonlinear phenomena which are the cause for both acoustic and thermal power dissipation. Among the many effects usually described are the acoustically enhanced thermal pumping [1,2], acoustically induced DC flows [3,4,5], complex aerodynamical effects due to geometrical singularities at interfaces between elements of different porosity or at geometric discontinuities [6], or nonlinear propagation leading to higher harmonics generation [7,8].…”