The characteristics of methane/oxygen premixed flame dynamics in a meso-scale reactor under fuel rich condition

Abstract

The high surface-to-volume ratio of a micro combustor causes the flame motion to vary from that of a large-scale combustor. The effects of the length and height of the combustor on the flame behaviors are studied to revel the flame pattern. Five flame regimes are observed, namely diffusion flame, steady flame, partly RERI flame, fully RERI flame and flame flashback and extinction. The equivalence ratio range of each flame regime in several combustors is measured. The flame position of the steady flame and the corresponding wall temperature as well as the frequency and propagating distance of the RERI flame are investigated. The results show that the change of combustor length has a significant effect on the extinction area and the increase and decrease of the height of the combustor channel lead to a shift towards fuel rich side and fuel lean side respectively. Longer combustor broadens the low equivalence ratio limit of the steady flame. Higher combustor channel increases the effect of inlet Reynolds Number on the high equivalence limit of steady flame. Combustor length has little effects on the RERI flame, whereas higher channel height of combustor increases the propagating distance of the RERI flame but decreases the frequency.