Active Control of Combustion Instability: Theory and Practice

One of the most successful applications of control technology in fluid systems is in the context of dynamic instability in continuous combustion systems. Recent results in this area have shown unequivocally that active control is not only a feasible technology for reducing the unsteady pressure oscillations, but also that the approach can be scaled up to large-scale industrial rigs. Models of combustion instability have been derived using both physically based and system-identification based methods. Optimal, time-delay, and adaptive controllers have been designed using these models and demonstrated to lead to an order of magnitude improvement in a range of combustion rigs over empirically designed control methods. In this paper, we present a survey of the existing theory that includes modeling and control of pressure instability in combustion systems and the practical applications of active control to-date in small, medium, and large-scale combustion rigs.