A review of active control of combustion instabilities

Abstract

This paper presents an overview of active control of combustion instabilities. First, the paper will use a simple model to present the rationale that motivated the development of active control systems (ACS) for unstable combustors. Next, the design and performance of earlier ACS will be discussed to identify control system components and control approaches that offer the most promise for practical applications. The bulk of the paper will discuss active control research at Georgia Tech, conducted by the author and colleagues. It will describe the architecture of the developed ACS, adaptive and nonadaptive active control approaches, and the performance of critical ACS components. Emphasis will be placed upon the performance of the observer that determines the state of the unstable combustor in real time and the fuel injector actuator that can modulate the injection rate of a fuel stream over a wide frequency range (e.g., 0–2000 Hz). This will be followed by descriptions of the performance of this ACS under different modes of operation when applied to different combustors. These results will show that the developed ACS can rapidly damp combustion instabilities whose characteristics vary with time and are not known a priori. The paper will close with a discussion of needed research and development efforts.