Consequences of flame geometry for the acoustic response of premixed flames

Dynamics and control of premixed combustion systems based on flame transfer and describing functions

“…Theoretical models accompanied by numerical validations have been derived in parallel yielding analytical descriptions and useful dimensionless parameters controlling the flame dynamics (Fleifil et al 1996;Dowling 1999;Schuller et al 2003a;Preetham, Santosh & Lieuwen 2008;Blumenthal et al 2013;Steinbacher et al 2019). This research motivated by practical instability problems encountered in gas turbines is also driven by the need for a fundamental understanding of combustion dynamics phenomena.…”

Flame interactions in a stratified swirl burner: Flame stabilization, combustion instabilities and beating oscillations

“…It is driven by both velocity and equivalence ratio fluctuations, resulting in both flame area and heat release intensity modulations. However, for a premixed flame, as its equivalence ratio is fixed, flame area modulations, such as surface wrinkling or vortex roll-up, dominate the flame dynamics when it is exposed to velocity fluctuations [18,36,38].…”

“…38 s. According to the Rayleigh criterion[41], a positive (negative) value stands for a constructive (destructive) effect driving (damping) the thermoacoustic instabilities. The Rayleigh index map of Case P f M a is shown in Fig.4(b) where the whole flame is positive, indicating that the flame heat release perturbation in the whole region is positively coupled with P .…”

Combining analytical models and LES data to determine the transfer function from swirled premixed flames

“…For the model derivation, although alternatives exist [34] , we make use here of the convective model for laminar V-shaped flames introduced by Schuller et al in [30] and where a convective velocity perturbation propagates in the vertical direction in the laboratory reference frame. That is:…”