Low-order modelling of the light-round ignition transient in a premixed annular combustor

Abstract

This work presents a series of simulations of the light-round process in a premixed annular combustor, consisting of 18 individual swirl bluff body burners, using improvements to the previously-published stochastic low-order model SPINTHIR that mimics flame propagation with a Langevin particle model and continuous new particle generation. The improvements presented include the effect of dilatation and a stochastic component to the quenching criterion, resulting in capturing reasonably well the bending behaviour of the turbulent flame speed with turbulent intensity. The results showed that the light-round mechanism was well reproduced compared to experiments. The various versions of the model captured the trend of light-round time τLR as a function of the mixture’s laminar flame speed with different degrees of accuracy. Overall, the results here reported improve our low-order capability to model the ignition transient in complex multi-burner configurations, which can help the design process of gas turbine combustors.