Examination of the Flame Blowout Characteristics of a Jet Diffusion Flames Burner in Co- and Cross-Flowing Air

The blowout limit of a jet diffusion flame was shown experimentally to improve significantly through the introduction of an auxiliary fuel in the surrounding air. A small experimental burner was devised so that the auxiliary fuel could be introduced and controlled independently of the main jet fuel, through a number of small pilot jets uniformly distributed around the main central fuel jet. This burner arrangement eliminated the likelihood of a flame flashing back into the surrounding atmosphere and some fuel escaping combustion. The burner was tested with methane as the fuel both for the main jet and the auxiliary side jets. Tests were made for both co-flow and cross-flow air streams of uniform velocity. It is shown that the arrangement adopted for auxiliary fuel introduction produced improvements in the flame blowout limits of the burner under both types of surrounding flow conditions. For the conditions considered, the blowout limits were of higher values in cross flow than for the corresponding co-flowing air streams.