Response of triple flame to temporal change in concentration gradient

This research proposes a study of the methane-air triple flame characteristics related to concentration gradients. Flame behaviors of transitional change in concentration gradients have to be understood for stability control of lifted flame. For this purpose, response of triple flame is studied experimentally using temporal change of concentration gradient from steep to gentle or opposite. The flow field structures were measured by particle image velocimetry to understand the mechanism of changing concentration gradients in front of the leading edge of the flame. The results are that, the leading edge of the flame in Case B (from gentle to steep) takes longer route than Case A (from steep to gentle) from steady state before changing concentration gradient to steady state after changing concentration gradient. That is to say, there are different behavior (hysteresis) between Case A and Case B. Flow lines are extended unsymmetrical in steep condition. This is because the route of the leading edge of the flame changes so that hysteresis behavior occur.