In this paper, the dynamic instabilities of a Trapped Vortex Combustor (TVC) were studied experimentally. In particular, the recurrences in the pseudo-phase space of pressure and radiant energy uctuations were analyzed with a view to quantifying the recurrence plots and study the nonlinear behavior of the thermoacoustic instabilities. The present results reveal clearly three different regimes: combustion noise regime characterized by chaotic low-amplitude aperiodic oscillations, a transition regime towards instabilities comprised of intermittent high-amplitude periodic bursts that emerge among low-amplitude aperiodic oscillations, and the combustion instability regime formed by high-amplitude periodic oscillations. A quantification of the recurrence plots was performed by computing the recurrence rate index. The results show that the recurrence rate index fluctuated during the transition and dropped to a minimum in the proximity of instabilities. Therefore, the quantification of recurrence plots proved to be an useful method in order to define precursors that predict in advance combustion instabilities. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

Chaotic analysis of the thermoacoustic instabilities of a trapped vortex combustor

Troiani, G.
2018

Abstract

In this paper, the dynamic instabilities of a Trapped Vortex Combustor (TVC) were studied experimentally. In particular, the recurrences in the pseudo-phase space of pressure and radiant energy uctuations were analyzed with a view to quantifying the recurrence plots and study the nonlinear behavior of the thermoacoustic instabilities. The present results reveal clearly three different regimes: combustion noise regime characterized by chaotic low-amplitude aperiodic oscillations, a transition regime towards instabilities comprised of intermittent high-amplitude periodic bursts that emerge among low-amplitude aperiodic oscillations, and the combustion instability regime formed by high-amplitude periodic oscillations. A quantification of the recurrence plots was performed by computing the recurrence rate index. The results show that the recurrence rate index fluctuated during the transition and dropped to a minimum in the proximity of instabilities. Therefore, the quantification of recurrence plots proved to be an useful method in order to define precursors that predict in advance combustion instabilities. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
9781624105609
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.12079/4250
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