Abstract
The onset process of self-excited oscillation in a thermoacoustic engine is a nonlinear self-organization process far from equilibrium, and is of great importance for the operation of a thermoacoustic engine. From the viewpoint of thermodynamic stability analysis, the GlansdorffPrigogine stability criterion of non-equilibrium thermodynamics is used to study the onset process. The excess entropy for a single-component ideal-gas thermoacoustic system is formulated, and the procedure of introducing the GlansdorffPrigogine criterion into numerical computation is discussed. A modification of the GlansdorffPrigogine criterion is made to treat the errors deriving from the numerical computation. The computation is conducted on a standing-wave thermoacoustic engine to achieve the time evolutions of the excess entropy and the excess entropy production for different steady states corresponding to different given hot end temperatures of the stack. The modified GlansdorffPrigogine criterion is successfully used to judge the stability of steady state according to the computed time evolution of the excess entropy production, and then the onset temperature (i.e., the critical hot end temperature of the stack for the onset process) can be predicted with a resolution of 1 K.
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