Thermoacoustic instability and blowout are two challenges faced while operating combustors in lean premixed conditions. Till now, the dynamics of both these phenomena are studied in very different manner. Thennoacoustic instability is seen as the loss of dynamic stability of the system and blowout is described as the loss of static stability of the system. In this paper we provide a unified framework to describe the onset of thermoacoustic instability and the transition to blowout. We observe that in turbulent combustors, the dynamic regime prior to both onset of instability and blowout are characterized by intermittent acoustic oscillations. We also observe that the acoustic time series obtained from a turbulent combustor exhibit multifractal nature. We further characterize the multifractal nature of these oscillations and observe that while at the onset of instability the multifractal width estimated from unsteady pressure measurements reduces to zero indicating a loss of multifractality, as we approach blowout, the multifractal width increases. Using this knowledge we describe how a single detection system can be used to forewarn about an impending instability and an impending blowout.
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