An Experimental Study of the Stability of City Gas and PropaneTurbulent Non-Premixed Flames under Diluting Conditions

The stability behavior of jet non-premixed flame developing in a coflowing stream is studied experimentally, using city gas and propane as fuel gases. Effects of oxidant and fuel stream velocities and oxidant stream dilution have been studied. Two types of stability limits are observed. Blow-off of the rim-stabilized flame is the first stability limit. The second is the break-off or extinction of the turbulent portion of the flame at the transition point from laminar to turbulent flow. Oxidant and fuel streams are in environmental temperature. In dilution experiments, oxidant primary stream is oxygen as diluted with nitrogen or carbon dioxide. In the other experiments, oxidant is environmental air.