An experimental study of methane-oxygen-carbon dioxide premixed flame dynamics in non-adiabatic cylinderical meso-scale reactors with the backward facing step

In the present study, we experimentally evaluated the effects of geometrical parameters, Reynolds number, dilution percent, and equivalence ratio on methane-oxygen-carbon dioxide flame dynamics in non-adiabatic cylindrical meso-scale reactors with the backward facing step. Five flame regimes of blow-out, marginal, stationary (asymmetric and spinning), RERI, and flashback were observed during the tests. The results showed that adding carbon dioxide to methane-oxygen mixture could extend RERI flame regimes in the meso-scale reactors. Moreover, it was shown that the presence of RERI flame regime could lead to more uniform temperature distribution on the outer surface of the lengthy meso-scale reactors as compared to the stationary flame regimes. Also, it was demonstrated that increasing the average flow speed in the meso-scale reactors decreased the average frequency of RERI flame regimes.