Influence of burner surface temperature inhomogeneities on oscillation characteristics of premixed flames

Thermo-diffusively oscillating burner-stabilized flames provide sensitive targets for the validation and improvement of detailed chemical reaction mechanisms. Because these flames are typically modeled using a one-dimensional (1D) assumption due to their computational efficiency, the validity of this assumption under realistic experimental conditions remains unclear. In this work, premixed oscillating methane–air flames are simulated using two-dimensional (2D) numerical models. The role of spatial inhomogeneities of burner surface temperatures is investigated. Both synthetic and experimentally motivated temperature profiles are imposed at the burner surface. The results show that the dominant oscillation frequency is primarily determined by the maximum burner surface temperature. In contrast, the oscillation amplitude exhibits a strong dependence on the spatial temperature profile. Nearly one-dimensional bulk oscillations at the center evolve into wave-like, phase-shifted flame fronts along the radial direction. Thus, 1D simulations can reliably predict oscillation frequencies if the maximum burner temperature is known, while multi-dimensional simulations are required to capture spatial variations in the oscillation amplitude and boundary effects at the edge.
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Novelty and significance statement: This study bridges the gap between one-dimensional flame simulations and experiments on oscillating burner-stabilized flat flames by explicitly accounting for spatial inhomogeneities in inlet temperature fields. The novelty lies in incorporating measured and synthetic temperature distributions to quantitatively assess their influence on unsteady flame dynamics. Significantly, this approach unlocks transient operating regimes, such as thermo-diffusive oscillations, as a robust source of validation data. By utilizing oscillation frequencies and amplitudes alongside standard stable flame properties, this work facilitates a more rigorous validation of chemical kinetics models. Ultimately, incorporating these dynamic targets improves the predictive capability of 1D simulations and supports the development of highly accurate reaction mechanisms for complex fuel mixtures.