Experimental study of methane/air combustion in a Swiss-roll miniature combustor

To understand the operation features of a miniature Swiss-roll combustor, a methane/air premixed combustion experiment has been performed with the combustion limit of the combustor being obtained. The influence of a heat recirculation on the combustion limit of the combustor has also been studied. The test results show that when the methane flow rate is between 0.8 and 2.7 mg/s, the miniature combustor thus designed can fulfill a stable methane/air combustion and guarantee that the flame is located at the combustor center. With the heat recirculation being enforced, the oxygen enrichment limit of the combustor will be decreased from 0.7 (without heat recirculation) to 0.5. However, the combustion limit is not symmetrical to ER (stoichiometric equivalence ratio)=1. The fuel enrichment limit is small while the oxygen enrichment limit is large. At the same time, the authors have also conducted a numerical simulation of the miniature combustor. The simulation results show that the flow return zone at the combustor center enables the combustor to secure a stable operation in a relatively large range of combustion limit.