Nonlinear Oscillations of a Premixed Flame Stabilized on a Flat Burner

This work presents a combined experimental and theoretical investigation of oscillations in a premixed flame stabilized on a flat porous burner. The theoretical study is based on a reduced flame evolution model, formulated as a system of two nonlinear equations for the flame surface coordinate and its temperature. This approach enables extensive parametric studies of flame diffusion-thermal instability over a wide parameter range. Numerical simulations of the 2D model reveal various dynamic regimes, including periodic oscillations, beating modes, and multi-harmonic oscillations. These regimes are shown to arise from stability loss and the subsequent nonlinear interaction of multiple spatial perturbation modes. The existence of such complex dynamics has been experimentally confirmed for rich methane-air flame stabilized on a flat porous burner. The obtained experimental data – including instability development patterns – provide a valuable insights for validating detailed chemical reaction mechanisms of premixed gas combustion.