Ph.D. Proposal Presentation by Cliff Johnson
Thursday, December 21, 2000

(Dr. Ben Zinn, advisor)

"Adaptive Control of Combustion Instabilities Using Real-Time Modes Observation"


Combustion instabilities are a significant problem in combustion systems, particularly in Low NOx Gas Turbine combustors.  These instabilities result in large-scale pressure oscillations in the combustor, leading to degraded combustor performance, shortened lifetime, and catastrophic combustor failure.

The objective of this research is to develop a practical adaptive active control system that, coupled with an appropriate actuator, is capable of controlling the combustor pressure oscillations without a priori knowledge of the combustor design, operating conditions or instability characteristics.  The adaptive controller utilizes an observer that determines the frequencies, phases and amplitudes of the dominant modes of the oscillations in real time.  The proposed research includes development and testing of the adaptive controller on several combustors and on an unstable acoustic feedback system in order to analyze its performance.  The research also includes investigations of combustor controllability and combustor stability margin, which are critical issues for practical implementation of an active control system on an industrial combustor.  The results of this research will be directly applicable to a variety of combustors and can be implemented on full-scale industrial combustion systems.