Revisiting a Model for Combustion Instability Involving Vortex Shedding
| Autor: | Koushik Balasubramanian, R. I. Sujith, Bharat Tulsyan |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
General Chemical Engineering
Initial conditions Linear acoustic equations Combustion Linearization General Physics and Astronomy Energy Engineering and Power Technology Non-linearity Acoustic fields Damping Vortex shedding Instability Transient growth Galerkin technique Pseudospectral Normal behavior Thermoacoustic systems Acoustic pressures Smoke Limit cycle Galerkin method Sound pressure Acoustic mode Combustion instabilities Velocity fluctuations Physics Non-normality Nonlinear nature Reduced order models Thermochemistry General Chemistry Mechanics Acoustic interaction Vortex Nonlinear system Fuel Technology Classical mechanics Damped systems Unstable oscillation Combustor Combustion instability Test case High amplitudes Stability Linear equation |
| Zdroj: | Scopus-Elsevier |
| DOI: | 10.2514/6.2008-4573 |
| Popis: | We revisit a simple reduced order model (Matveev, K., and Culick, F. E. C, 2003, A Model for Combustion Instability Involving Vortex Shedding, Combust Sci. and Tech., 175, 1059) and re-examine its implications in light of the non-normal and nonlinear nature of combustion acoustic interactions. To this end, one-dimensional linear acoustic equations are used to model the acoustic field in an open-open duct. The Galerkin technique is then implemented to expand the acoustic pressure and velocity fluctuations in terms of the natural acoustic modes. The coupled thermoacoustic system is shown to be non-normal and nonlinear. This leads to complicated but interesting physics that were not examined in the earlier study. Examples showing transient growth leading to instability and bootstrapping in an initially decaying system are then presented. It is also shown that a vortex-based combustor reaches different limit cycle amplitudes for the same system parameters when subjected to different initial conditions. Further, the effect of damping on the non-normal behavior of the system is studied. A test case is presented that shows that for a lowly damped system, a slight increase in damping leads to high amplitude unstable oscillations. Finally, pseudospectral analysis is presented to study the non-normal behavior of such systems. |
| Databáze: | OpenAIRE |
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