Time-resolved thermometric investigation of flame quenching between parallel flat plates

Abstract

Understanding the quenching of flames by cold surfaces requires an accurate characterization of heat transfer. This study presents time resolved thermometry of flame quenching events, in a geometry that mimics a flame arrester located between two large tanks. The specificity of this arrangement was that the laminar flame in the quenching section could reach a relatively high apparent velocity, around 13 m/s. One-dimensional high-speed (10 kHz) filtered Rayleigh scattering (FRS) was implemented along with dynamic pressure measurements. Thermometry by FRS was used to measure the spatial and temporal evolution of the temperature in the flame front as well as in the burnt gases, as the flame propagated in the quenching section. Quenching was assessed by the analysis of pressure measurements. The flame propagated in a methane-air mixture of 0.8 equivalence ratio, initially quiescent at atmospheric pressure and room temperature. Three distances between the quenching elements, namely the two parallel flat aluminum plates, were investigated. The results showed that systematic quenching was obtained when the flame temperature decreased below 1600 K. In addition, the evolution of the integral of the temperature profile across the flame front could be used to predict quenching events. Based on heat transfer analysis, explanations for these results are proposed.