Reduced-order dynamic models for control of reactive fluid-flows

Combustion instability arises due to the inter-coupling between the heat release dynamics and acoustics in continuous combustion systems, especially in those designed to run at lean premixed conditions. We derive a reduced-order model of the combustion instability by studying the three basic components, acoustics, heat release, and flow impedance, and the dominant interactions between them. We show that these models are capable of exhibiting growing pressure oscillations, in the linear range, as well as limit cycles, in the nonlinear range. The role of linear and nonlinear model-based control in suppressing the combustion instability is illustrated