Accession Number:

ADA458815

Title:

Passive Control of Limit Cycle Oscillations in a Thermoacoustic System using Asymmetry

Descriptive Note:

Corporate Author:

CALIFORNIA UNIV SANTA BARBARA DEPT OF MECHANICAL AND ENVIRONMENTAL ENGINEERING

Report Date:

2006-09-05

Pagination or Media Count:

15.0

Abstract:

In this paper, we investigate oscillations of a dynamical system containing passive dynamics driven by a positive feedback and how spatial characteristics i.e. symmetry affect the amplitude and stability of its nominal limit cycling response. The physical motivation of this problem is thermoacoustic dynamics in a gas turbine combustor. The spatial domain is periodic passive annular acoustics which are driven by heat released from a combustion process, and with sufficient driving through this nonlinear feedback a limit cycle is produced which is exhibited by a traveling acoustic wave around this annulus. We show that this response can be controlled passively by spatial perturbation in the symmetry of acoustic parameters. We find the critical parameter values that affect this oscillation, study the bifurcation properties, and subsequently use harmonic balance and temporal averaging to characterize periodic solutions and their stability. In all of these cases, we carry a parameter associated with the spatial symmetry of the acoustics and investigate how this symmetry affects the system response. The contribution of this paper is a unique analysis of a particular physical phenomena, as well as illustrating the equivalence of different nonlinear analysis tools for this analysis.

Subject Categories:

  • Acoustics
  • Thermodynamics
  • Jet and Gas Turbine Engines

Distribution Statement:

APPROVED FOR PUBLIC RELEASE