Experimental and numerical studies on methane/air combustion in a micro swiss-roll combustor

To understand effects of an air groove on working characteristics of micro Swiss-roll combustors, combustion of premixed CH4/air is conducted in 2 micro Swiss-roll combustors, one with an air groove and the other without. Experimental results show that stable combustion of premixed CH4/air in 2 combustors can be achieved and the flame is kept in combustor's center. An air groove can extend flammable limit of the combustor and make it work at a larger excess air coefficient and a lower methane flow rate. Furthermore, it increases the radial surface temperature gradient on outer wall of the combustor. Additionally, the combustor with an air groove is numerically simulated. Numerical results indicate that hot combustion products play a strong role in heating incoming mixtures. On one hand, it makes premixed flame surface inclined across inlet channel; on the other hand, it makes flame position vary with flow velocity, excess air coefficient and heat loss to the environment.