Active control of thermoacoustic instability in combustion systems

Active control has been pursued vigorously to combat thermoacoustic instabilities in combustion processes. Despite the success reported in experimental investigations, a systematic procedure by which active control can be designed and implemented is currently not available. In this paper, we discuss the active control of a premixed combustor. The model structure in the presence of a loudspeaker and a microphone is derived starting from first principles. We demonstrate that this model captures the effects of several coupled modes, the locations of the actuator-sensor pair, and an appropriate control design. A compensator is shown to provide the necessary phase characteristic leading to stabilization when a single mode is dominant