Influence of a Bluff-Body Flame Holder on Blowout Limits of a Premixed Flame into a Stream of Air.(Dept.M)

Abstract

Flame stabilization in a stream of air is an indispensable process in most industrial combustion devices. This is performed by means of either the recirculation zone formed in the wake of a bluff - body or step, the recirculation flow in the central region of a swirling flow or a hot body. In this study an experimental investigation on the influence of a bluff-body flame holder on blow out limits of a premixed flame into a stream of air has been carried out. A premixed mixture of commercial butane-air is introduced co-axially through a stream of air inside a transparence cylindrical combustion duct. A cylindrical and spherical bluff - body flame holders have been determined. Measurements of critical equivalence ratio6 at lean and rich blowout limits have been obtained. AISO, measurements of temperature and concentrations in the resulting flames are carried out. The results show that the blowout limits are increased as flame holder size increased. Both, lean, rich and high speed blowout limits of flames are widened with increase in dimensions of flame holders. The results also demonestrated that further extended are obtained with cylindrical flame holders' rather than with the spherical one.