Flame blowout: Transition to an absorbing phase

Abstract

The turbulent flame inside a gas turbine engine is susceptible to local extinction leading to global extinguishment or blowout at fuel lean conditions. Flame blowout is traditionally viewed as a loss of static stability of the combustor. However, flames often exhibit rich dynamics as blowout is approached suggesting that a more comprehensive description of the dynamics of flame blowout, which could lead to reduced order models, is necessary. A turbulent flame can be considered as a collection of a large number of flamelets. The population dynamics of these flamelets could be used to model the overall flame behavior as a contact process. In this context, flame blowout can be viewed as the population of flamelets approaching zero, in other words, extinction of flamelets. In this paper, we employ a cellular automata based model to study the emergent dynamics of the population of such flamelets. We show that the model is able to qualitatively capture interesting dynamics that a turbulent flame inside a combustor exhibits close to flame blowout. Furthermore, we show that flame blowout is similar to a threshold-like transition to an absorbing phase.