Laboratory investigation into fractal characteristics of methane explosion flame

This article presents the results of an experimental study which aims to examine flame propagation pattern occurring during methane explosion under different gas concentrations. Five methane-to-air volume concentration ratios are tested, namely 8, 9.5, 9.7, 10, and 11%. Flame images are captured with high-speed camera and examined with fractal analysis of triple-prismatic surface area. The experimental results suggest that the closer the methane concentration is to the optimal equivalence ratio, the greater the maximum fractal dimension of the explosion. It is shown that the maximum fractal dimension occurs at a methane concentration of 9.5% when the methane concentration moves closer to the optimal equivalence ratio and the explosion is most intense. The fractal dimension and its rate of change serve directly as indicators of the explosion intensity, the gradient of intensity, and the propagation pattern of the entire flame. These results shed light on the dynamic characteristics of flame propagation occurring in methane explosion.