Flame propagation and burning rates of methane-air in a closed combustion vessel

Abstract

The propagation and burning rates of methane-air mixtures were investigated at initial atmospheric pressure with temperature range of 298-302K and equivalence ratio range of 0.8 to 1.3. Experiments were performed in a cylindrical constant volume combustion chamber where the mixture is ignited by centrally located electrodes. The images of spherically expanding flame were observed and recorded using schlieren photography technique with high speed camera system. Analysis of the flame area yield flame radii and further burning rates in term of outwardly flame speed propagation can be calculated. Results shows that smooth spherical flames were observed throughout the flame propagation for all equivalence ratios. The fastest flame propagation was recorded at equivalence ratio 1.0 and 1.2. In addition, flame speed of each equivalence ratio exhibits small fluctuation probably arising from acoustic disturbance. This disturbance becomes more apparent at higher equivalence ratio.