Dynamics of premixed hydrogen/air flames in mesoscale channels

Direct numerical simulation with detailed chemistry and transport is used to study the stabilization and dynamics of lean (φ=0.5φ=0.5) premixed hydrogen/air atmospheric pressure flames in mesoscale planar channels. Channel heights of h=2h=2, 4, and 7 mm, and inflow velocities in the range 0.3⩽UIN⩽1100 cm/s0.3⩽UIN⩽1100 cm/s are investigated. Six different burning modes are identified: mild combustion, ignition/extinction, closed steady symmetric flames, open steady symmetric flames, oscillating and, finally, asymmetric flames. Chaotic behavior of cellular flame structures is observed for certain values of UINUIN. Stability maps delineating the regions of the different flame types are finally constructed.