An experimental study on the stability of jet diffusion flame

The stability behavior of jet diffusion flame developing in a coflowing high temperature air stream was studied experimentally, using city gas and hydrogen as fuel gases. The primary variables studied were temperature and velocity of the air stream. Two distinct types of stability limits were observed. The first is the blow-off of the rim-stabilized flame, which is familiar and has been studied by a number of investigators. The second is the break-off or extinction of the turbulent portion of the flame at the transition point from laminar to turbulent flow. The second limit is quite unfamiliar and is interesting in relation to the structure of turbulent diffusion flames. The important implications of the experimental findings concerning the stability and the structure of turbulent diffusion flames is discussed.