Premixed Double Concentric Jets Flame with Gas Injection in Recirculation Zone

Abstract

Air, fuel gas and fuel-air mixture injection into a recirculation zone formed behind a thick burner rim were examined. Flame stability limits, residence times in the recirculation zone and inflow ratios of injected gas were measured. Flame stability limits were widened by fuel or mixture injection. Mixture injection was most effective. The length of the recirculation zone and residence time in the recirculation zone with injection coincided with these without injection. Inflow ratios of the injection gas in the recirculation zone were about 80% irrespective of the injection rate or mixture strength of the injected gas.