Effects of Gravity on Plane-Symmetric Rod-Stabilized Flame Stabilization

Resumo

The current research is focused on the study of methane-air flame stabilization under the flow geometry variation for normal and upside-down (reverse) flame orientation. The experimental studies of plane-symmetrical rod-stabilized flames under the normal and reverse-oriented gravity conditions were carried out. The results of numerical simulation are presented. The blow-off is shown to be the function of stabilization-body position. We consider both V-shaped and M-shaped plane-symmetrical open flames for different Reynolds numbers, fuel-air ratio and flame orientation relative to the gravity direction. Blow-off limits appear to be independent on the gravity for the lean methane-air mixtures while the quenching processes are different for the normal and reverse-oriented gravity conditions. Blow-off is also accompanied by the chemiluminescence intensity decrease under reverse-oriented gravity conditions, which is exhibited in localized plume extinction and gradual quenching. While under the normal gravity, it appears via stepwise vortex separation from the lateral plume parts. Under such conditions chemiluminescence intensity remains almost constant. The blow-off time scale under the normal gravity conditions is bigger as compared to reversed-oriented ones by several times.