Premixed flames in a narrow slot with a step-wise wall temperature: linear stability analysis and dynamics

Abstract

Premixed flames in a narrow slot with a prescribed wall temperature subject to a Poiseuille flow are investigated for various Lewis numbers within a constant den- sity model and using irreversible Arrhenius kinetics. A global stability analysis of steady-state solutions is carried out together with time-dependent direct numerical simulations. The unsteady results are found in good agreement with the stability results. Additionally, it is demonstrated that for some values of the flow rate a mul- tiplicity of time-periodic states can take place. The multiple time-periodic solutions arise from combinations of various unstable modes, symmetric and non-symmetric with respect to the channel midplane.