Combustion Dynamics and Control in Liquid-Fueled Direct Injection Systems

摘要

Experiments evaluating the performance of a closed-loop combustion stabilization algorithm show that the method can reduce the magnitude of pressure oscillations in a liquid-fueled combustor by more than 50%. This paper describes the gas-turbine type combustor facility used for the experiments, associated instrumentation, unsteady combustion experiments, and the control scheme employed to suppress the natural thermo-acoustic instability. The combustor exhibits a natural instability at 140 Hz, the result of dynamic coupling between the combustor pressure field and the combustion heat release. Experiments to characterize the influence of operating parameters on the behavior of the instability are described. The control algorithm, amplitude- based pulse-width modulation, is used to modulate flow through one stream of a dual-passage fuel injector at such a phase that the instability amplitude is reduced. The paper concludes with a discussion of the control experiments, showing that the algorithm was successful in reducing the pressure oscillation.