Flame stabilization in a counter current heat-regenerative small-combustor

Stabilization of a methane-air premixed flame in a heat regenerative micro-combustor was investigated. A counter current combustor having two shallow channels and a combustion space was developed. The characteristic distance of the channel (channel gap) was less the ordinary quenching distance. Configurational effects of the channel gap and the thickness of the middle wall located between two channels of unburned and burned mixtures were examined concerned with the experimental flame stabilization conditions and the flame characteristics. Flashback conditions are triggered by the channel gap while the blowout conditions are strongly affected by the middle wall thickness. In particular, two distinctive modes of radiation and stirred reaction were observed. Additional numerical study was conducted for the flame in a narrow channel and it shows sensitive dependency of the flame propagation velocity on heat loss from the wall. This study shows practical effects of fundamental design parameters and helps understanding flame behaviour in a heat regenerative combustor.