The effect of intrinsic instability on the surface topography of spherical 2-acetylfuran flame

Abstract

The intrinsic instability of 2-acetylfuran (2-AF) expanding flame has been investigated at initial temperatures of 453–493 K, pressures of 1–3 bar, and equivalence ratios of 0.8–1.4. The linear stability theory was used to analyze the influence of the initial temperatures, initial pressures, and equivalence ratios on the 2-AF flame intrinsic instability. Moreover, an image processing technique was applied to obtain the experimental cell-wavenumber from the topography of 2-AF cellular flame to quantitatively analyze the local cell proliferation. The topography of the 2-AF expanding flame shows that the initial pressures and equivalence ratios are the two influential factors to its intrinsic instability. More specifically, the higher the initial pressures, as well as the equivalence ratios, the earlier the time of the flame becomes unstable. Furthermore, according to the comparison between the local experimental and theoretical wavenumbers, it is found that the average local experimental wavenumber falls within the unstable zone predicted by the linear stability theory. Last but not least, the cell-wavenumber distribution in the different regions on the 2-AF expanding flame surface indicates that the initial crack has a weaker shaping effect on the flame surface than the formation of small spontaneous cells.